Spawn is the eggs and sperm released or deposited into water by aquatic animals . As a verb, to spawn refers to the process of freely releasing eggs and sperm into a body of water (fresh or marine); the physical act is known as spawning . The vast majority of aquatic and amphibious animals reproduce through spawning. These include the following groups:
193-570: The River Irwell ( / ˈ ɜːr w ɛ l / UR -wel ) is a tributary of the River Mersey in north-west England. It rises at Irwell Springs on Deerplay Moor, approximately 1 + 1 ⁄ 2 miles (2.5 kilometres) north of Bacup and flows southwards for 39 mi (63 km) to meet the Mersey near Irlam Locks. The Irwell marks the boundary between Manchester and Salford , and its lower reaches have been canalised and now form part of
386-598: A cantilevered footway providing an alternative crossing to a ferry. In 1905 the now demolished Widnes-Runcorn Transporter Bridge opened and took cars and passengers via a cable car. The Silver Jubilee Bridge , completed in 1961, is immediately adjacent. East of Warrington, the M6 motorway crosses the river and the Manchester Ship Canal on the Thelwall Viaduct . When the viaduct opened in 1963, it
579-677: A tidal bore from Hale as far upstream as Warrington. On 7 December 2022, the Liverpool City Region mayor announced cooperation between the City Region and K-water of South Korea , who built and operates the Sihwa Lake Tidal Power Station , in order to construct a similar operation on the River Mersey. The river gave its name to Merseybeat , developed by bands from Liverpool, notably
772-427: A River Conservancy Committee; they appointed a river inspector, and had to power to take action against anyone polluting the river. The Rivers Pollution Prevention Act 1876 ( 39 & 40 Vict. c. 75) was designed to solve the problems of river pollution, but it was largely ineffective. It did, however, lay the groundwork for the more draconian legislation which followed, and in 1891 the Mersey and Irwell Joint Committee
965-586: A border between the ancient kingdoms of Mercia and Northumbria . For centuries it has formed part of the boundary between the historic counties of Lancashire and Cheshire . The Mersey starts at the confluence of the River Tame and River Goyt in Stockport . It flows westwards through south Manchester , then into the Manchester Ship Canal near Irlam Locks, becoming a part of
1158-552: A boundary' and ēa , 'a river'. The Mersey was possibly the 'border river' between Mercia and Northumbria . Its Welsh name is Afon Merswy . Prior to Anglo-Saxon conquest of the region, the river was almost certainly known by a Celtic name - recorded by Ptolemy as "Seteia" (as the Southern border of the Brittonic " Setantii " tribe). "Seteia" and "Setantii" both lack clear Celtic roots, leading some to suggest that this
1351-464: A breeding site. The females choose large males that are successfully defending prime breeding sites which the females find attractive. For example, sculpin males defend "caves" underneath rocks which are suitable for the incubation of embryos. Another way males get to mate with several females is through the use of leks. Leks are places where many fish come together, and the males display to each other. Based on these displays, each female then selects
1544-480: A classification of the spawning behaviours of fish by Balon (1975, 1984) into reproductive guilds . This classification is based on how the eggs are fertilized (internal or external spawners), where the eggs are deposited ( pelagic or benthic spawners), and whether and how the parents look after the eggs after spawning (bearers, guarders and nonguarders). Nonguarders do not protect their eggs and offspring after spawning Open substrate spawners scatter their eggs in
1737-772: A few days and replace the dominant male. This is found amongst coral reef fishes such as groupers , parrotfishes and wrasses . It is less common for a male to switch to a female ( protandry ). As an example, most wrasses are protogynous hermaphrodites within a haremic mating system. Hermaphroditism allows for complex mating systems. Wrasses exhibit three different mating systems: polygynous, lek-like , and promiscuous mating systems. Group spawning and pair spawning occur within mating systems. The type of spawning that occurs depends on male body size. Labroids typically exhibit broadcast spawning, releasing high amounts of planktonic eggs, which are broadcast by tidal currents; adult wrasses have no interaction with offspring. Wrasse of
1930-840: A forage fish of the smelt family found in the Atlantic and Arctic oceans. In summer, they graze on dense swarms of plankton at the edge of the ice shelf. Larger capelin also eat krill and other crustaceans . The capelin move inshore in large schools to spawn and migrate in spring and summer to feed in plankton rich areas between Iceland , Greenland , and Jan Mayen . The migration is affected by ocean currents . Around Iceland maturing capelin make large northward feeding migrations in spring and summer. The return migration takes place in September to November. The spawning migration starts north of Iceland in December or January. The diagram on
2123-472: A green route to and from the centre of Manchester. The 28 hectare flood basin will protect surrounding properties by holding up to 650 million litres of water during flood conditions. The scheme, utilises an 'offline' storage basin, created in a meander of the Irwell on the site of the old Manchester Racecourse , that will work in tandem with the existing flood storage area at Littleton Road. The embankment around
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#17327730469422316-616: A mile-long landscaped walkway in Manchester city centre and developers announced plans to develop three bricked-up railway arches on the side of the river, opposite Manchester Cathedral, into a wine bar and restaurant. In 1988 Manchester's first water bus made its maiden voyage from the New Bailey Landing Stage, then known as the Mark Addy Quay, on a five-mile (8 km) inaugural round trip to Salford Quays By
2509-400: A pair of gonads , which release sperm in response to hormones in the female's bloodstream indicating egg release. This ensures that, when the female is ready to spawn, she has a mate immediately available. A single anglerfish female can "mate" with many males in this manner. Polygynandry occurs when multiple males mate indiscriminately with multiple females. This mutual promiscuity is
2702-503: A particular subgroup of the family Labridae , Labrini, do not exhibit broadcast spawning. Less commonly hermaphrodites can be synchronous , meaning they simultaneously possess both ovaries and testicles and can function as either sex at any one time. Black hamlets "take turns releasing sperm and eggs during spawning. Because such egg trading is advantageous to both individuals, hamlets are typically monogamous for short periods of time–an unusual situation in fishes." The sex of many fishes
2895-632: A point of access: the Manchester Bolton & Bury Canal from 1809, and the Manchester and Salford Junction Canal from 1839. The previous year, the short Hulme Locks Branch Canal had also connected the Irwell to the Bridgewater Canal at Castlefield. All are now non-navigable, although the first is under restoration. As the 19th century progressed, the increasing need for large freight carriers led to Liverpool 's dominance as
3088-411: A pollution incident affected approximately 2 + 1 ⁄ 2 miles (4 kilometres) of the river between Rawtenstall and Ramsbottom , causing the death of more than 36,000 fish. The large number of fish killed did however serve to illustrate how much the river had improved from the lifeless, "melancholy stream" of the 1950s. In 2005 a £1M project to make the river "the cleanest it has been for decades"
3281-639: A port. Manchester became increasingly reliant on its Merseyside neighbour for its imports and exports, but the handling charges and dues charged by the Mersey Docks and Harbour Board made goods from Manchester uncompetitive. A solution was to build the Manchester Ship Canal. In 1887 the Bridgewater Navigation Company was purchased by the Manchester Ship Canal Company with a cheque for £1,710,000, which
3474-512: A quarry it owned in Scotland for construction of the quays. Birkenhead grew quickly in the 19th century following the introduction of steamships , the earliest being the wooden paddle steamer Elizabeth in 1815. Docks were developed along with a shipbuilding industry , flour milling and soap manufacture on the river's Cheshire bank. Seaforth Dock , a freeport on the Liverpool side of
3667-488: A relatively small number of embryos and retain them for a few weeks to 16 months or longer. The shorter times spans are characteristic of species that eventually deposit their embryos in the environment, surrounded by a horny capsule; whereas the longer periods are characteristic of sharks that retain the embryos until they are ready to emerge as actively swimming young." However, some fish do not fit these categories. The livebearing largespring gambusia ( Gambusia geiseri )
3860-489: A retired chemical engineer claimed that the pleasure boat was "leaving clouds of methane in its wake as it disturbed sediment on the river bed". However, in 1991 a feature article appeared in the magazine Lancashire Life extolling the virtues of the cruise, and stating that the Irwell "once thought a liability is in fact a major asset to urban regeneration ... now the twin cities compete to befriend her, to dress her in finery and proudly introduce her back into society. And
4053-519: A river than a flood of liquid manure, in which all life dies, whether animal or vegetable, and which resembles nothing in nature, except, perhaps, the stream thrown out in eruption by some mud-volcano. In the Victorian era passenger boat trips were popular but cut-short by the foul smells from the river. In 1862 the Corporation of Salford promoted an Act of Parliament enabling them to establish
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#17327730469424246-666: A run-down area of Salford and to create up to 8,000 new jobs. In May 1995 a new 30-mile (48 km) long multimillion-pound arts trail, to be known as the Irwell Sculpture Trail , was reported in the Manchester Evening News and in June 1997 work began on the £10 million Lower Irwell Valley Flood Defence Scheme in Lower Kersal. In July 2000 there was a setback for the clean-up programme when
4439-635: A scheme for improving a section of the river between Littleton Road and Adelphi Weir in Salford for boating purposes was included in Greater Manchester Policy Committee's capital programme for 1981/82. County Councillors at a recent committee meeting had criticised the condition of the river, with the councillor for the Metropolitan Borough of Oldham calling it "quite revolting and horrible". A spokesperson for
4632-480: A series of sandstone and shales . The lower sections of the river run through a landscape where the bedrock is of Permian and Triassic age, though alluvial and river terrace deposits often obscure the rock strata. The glaciers of the Pleistocene epoch radically re-shaped the landscape and then retreated, leaving behind deposits of sand, pebbles and boulder clay that formed the fluvioglacial ridges of
4825-400: A significant temperature change, often in spring. Males chase females, prompting them to release their eggs by bumping and nudging them. As the female goldfish spawns her eggs, the male goldfish stays close behind fertilizing them. Their eggs are adhesive and attach to aquatic vegetation. The eggs hatch within 48 to 72 hours. Within a week or so, the fry begins to assume its final shape, although
5018-605: A species is all-male or all-female. Unisexuality occurs in some fish species, and can take complex forms. Squalius alburnoides , a minnow found in several river basins in Portugal and Spain, appears to be an all-male species. The existence of this species illustrates the potential complexity of mating systems in fish. The species originated as a hybrid between two species, and is diploid , but not hermaphroditic. It can have triploid and tetraploid forms, including all-female forms that reproduce mainly through hybridogenesis . It
5211-423: A species is either male or female, and remains that way throughout their lives. Most fish are gonochorists, but hermaphroditism is known to occur in 14 families of teleost fishes. Usually hermaphrodites are sequential , meaning they can switch sex, usually from female to male ( protogyny ). This can happen if a dominant male is removed from a group of females. The largest female in the harem can switch sex over
5404-438: A substrate and guard them until the eggs hatch. After hatching, the female picks up the fry and keeps them in her mouth. When the fry can fend for themselves, they are released. Some eartheaters are larvophile mouthbrooders. The beginning of the evolutionary process of livebearing starts with facultative (optional) internal bearing. The process occurs in several species of oviparous (egg-laying) killifishes which spawn in
5597-496: A tourist attraction offering cruises that provide an overview of the river and surrounding areas. Water quality in the Mersey was severely affected by industrialisation, and in 1985, the Mersey Basin Campaign was established to improve water quality and encourage waterside regeneration. In 2009 it was announced that the river is "cleaner than at any time since the industrial revolution" and is "now considered one of
5790-437: A year may pass before they develop a mature goldfish colour; until then they are a metallic brown like their wild ancestors. In their first weeks of life, the fry grow quickly—an adaptation born of the high risk of getting devoured by the adult goldfish. Carp typically spawn in the spring and summer, depending on the climate and conditions. Oxygen levels of the water, availability of food, size of each fish, age, number of times
5983-558: A young boy from a particularly sewage-laden section of the river. After this he became ill, and died of tuberculosis in 1890 aged 51. He had rescued more than 50 people from the river during his lifetime. In 1939, the Mersey and Irwell Joint Committee was superseded by the Lancashire Rivers Board, but wartime conditions brought about further deterioration of the river. In 1951, the Rivers (Prevention of Pollution) Act
River Irwell - Misplaced Pages Continue
6176-579: A £70 million redevelopment scheme for Pomona Docks in Salford, to include a marina, homes, offices and other commercial developments. In 1990, the newly formed Mersey and Irwell Packet Company launched regular tourist trips along the river from a landing stage opposite the Granada Studios Tour entrance in Quay Street, taking in the stretch from Castlefield to Salford Quays. This was not universally welcomed as, by September of that year,
6369-508: Is also designated as a Local Nature Reserve (LNR). The second site is Ashclough, which is a site of geological interest. These two SSSIs are among the 21 found in Greater Manchester . In Salford the river flows through Clifton Country Park and Kersal Dale Country Park, both of which have been designated as LNRs. Grey herons , cormorants , mute swans , kingfishers and many species of geese and ducks are regularly sighted on
6562-438: Is also true of cartilaginous fishes (such as sharks , rays and skates ). Spawn consists of the reproductive cells ( gametes ) of many aquatic animals, some of which will become fertilized and produce offspring. The process of spawning typically involves females releasing ova (unfertilized eggs) into the water, often in large quantities, while males simultaneously or sequentially release spermatozoa ( milt ) to fertilize
6755-444: Is an "investment by parents in offspring that increases the offspring's chances of surviving (and hence reproducing). In fish, parental care can take a variety of forms including guarding, nest building, fanning, splashing, removal of dead eggs, retrieval of straying fry, external egg carrying, egg burying, moving eggs or young, ectodermal feeding, oral brooding, internal gestation, brood-pouch egg carrying, etc." Territorial behaviour
6948-441: Is an external method of reproduction where the female releases many unfertilised eggs into the water. At the same time, a male or many males release a lot of sperm into the water which fertilises some of these eggs. The eggs contain a drop of nutrient oil to sustain the embryo as it develops inside the egg case. The oil also provides buoyancy, so the eggs float and drift with the current. The strategy for survival of broadcast spawning
7141-615: Is called coral because it turns bright red when cooked. Roe (reproductive organs) are usually eaten either raw or briefly cooked. "The reproductive behaviour of fishes is remarkably diversified: they may be oviparous (lay eggs), ovoviviparous (retain the eggs in the body until they hatch), or viviparous (have a direct tissue connection with the developing embryos and give birth to live young). All cartilaginous fishes—the elasmobranches (e.g., sharks, rays, and skates)—employ internal fertilization and usually lay large, heavy-shelled eggs or give birth to live young. The most characteristic features of
7334-587: Is constricted, this material is then deposited and can contribute to a reduction in channel capacity. The origins of the name "Irwell" are uncertain but many accept the Anglo-Saxon origin, ere-well , meaning "hoar or white spring". The first part of the name may also be the Brittonic *ar , an ancient river-name element that implies horizontal motion, "flowing", "rising" or else "springing up". Flint scrapers , knives and other materials associated with
7527-408: Is difficult for fish to find partners, or when both sexes look after the young. Many tropical cichlids , which rear their young together in locations where they must fiercely defend against competitors and predators are monogamous. "In some pipefishes and seahorses , development of eggs takes a long time before the female can place them in the brood pouch of a male, where they are fertilized. While
7720-610: Is dominated by large and aggressive males. Cuckoldry is a variant of polyandry, and can occur with sneak spawners (sometimes called streak spawners ). A sneak spawner is a male that rushes in to join the spawning rush of a spawning pair. A spawning rush occurs when a fish makes a burst of speed, usually on a near vertical incline, releasing gametes at the apex, followed by a rapid return to the lake or sea floor or fish aggregation. Sneaking males do not take part in courtship. In salmon and trout, for example, jack males are common. These are small silvery males that migrate upstream along with
7913-489: Is generally necessary for guarders, and the embryos are almost always guarded by males (apart from cichlids). There is a need to be territorial because looking after embryos usually includes defending the site where they are being looked after. It also often means there is competition for the best egg-laying sites. Elaborate courtship behaviour is usual among guarders. Guarding males keep the embryos safe from predators, keep oxygen levels high by fanning water currents, and keep
River Irwell - Misplaced Pages Continue
8106-534: Is no doubt the pollution is clearing. It will be a long job, but we are sure there is a future for angling in the river. The report went on to state that the society "intends to carry out stocking operations soon". In 1972 the newspaper reported that "tiddlers" (small fish) had been seen swimming in the "notorious inky Irwell" near Peel Park, Salford . The Deputy chief water quality officer for Salford, Mr. Eric Harper, said: Ten years ago, any fish getting as far down as Salford would have been killed almost immediately by
8299-450: Is not fixed, but can change with physical and social changes to the environment where the fish lives. Particularly among fishes, hermaphroditism can pay off in situations where one sex is more likely to survive and reproduce, perhaps because it is larger. Anemone fishes are sequential hermaphrodites which are born as males, and become females only when they are mature. Anemone fishes live together monogamously in an anemone , protected by
8492-760: Is now part of the Merseyrail network. Two road tunnels pass under the estuary from Liverpool. By road, the Queensway Tunnel opened in 1934 connecting the city to Birkenhead, and the Kingsway Tunnel , opened in 1971, connects with Wallasey . Further upstream, the Runcorn Railway Bridge over the river at Runcorn Gap was built in the 1860s for the London and North Western Railway on the mainline between London and Liverpool. It had
8685-517: Is often associated with r-strategists . However, most fish and other spawning animals are iteroparous. When the internal ovaries or egg masses of fish and certain marine animals are ripe for spawning they are called roe . Roe from certain species, such as shrimp , scallop , crab and sea urchins , are sought as human delicacies in many parts of the world. Caviar is a name for the processed, salted roe of non-fertilized sturgeon . The term soft roe or white roe denotes fish milt . Lobster roe
8878-494: Is often necessary to construct fish ladders and other bypass systems so salmon can navigate their way past hydroelectric dams or other obstructions such as weirs on their way to spawning grounds. Coastal fish often use mangroves and estuaries as spawning grounds, while reef fish can find adjacent seagrass meadows that make good spawning grounds. Short-finned eels can travel anything up to three or four thousand kilometres to their spawning ground in deep water somewhere in
9071-509: Is rare to find true parthenogenesis in fishes, where females produce female offspring with no input from males. All-female species include the Texas silverside , Menidia clarkhubbsi as well as the Amazon molly . Parthenogenesis has been recently observed in hammerhead sharks and blacktip sharks . It is also known to occur in crayfish and amphibians. This section is patterned after
9264-557: Is situated about 1 mile upstream from the Runcorn Gap where the river is considerably wider. From the Runcorn Gap, the river widens into a large estuary , which is 3 miles (4.8 km) wide at its widest point near Ellesmere Port . The course of the river then heads north, with Liverpool to the east and the Wirral Peninsula to the west. The Manchester Ship Canal enters the river at Eastham Locks . The eastern part of
9457-503: Is the egg yolk, as in externally spawned eggs. This situation, also referred to as ovoviviparity , is characteristic of marine rock fishes and the Lake Baikal sculpins . This strategy allows these fish to have fecundities approaching those of pelagic fish with external fertilization, but it also enables them to protect the young during their most vulnerable stage of development. By contrast, sharks and rays using this strategy produce
9650-529: Is tidal from Howley Weir in Warrington. The canal let river traffic reach Warrington during low tides. During high spring tides, water levels often top the Howley Weir. Before construction of the ship canal, work to improve navigation on the Mersey included Woolston New Cut, bypassing a meander, and Howley Lock for craft to avoid the weir; the new cut and lock are still evident. The island formed between
9843-585: Is to be made to the North West Development Agency in October 2008 to support pre-project implementation work, including design and technical feasibility work. Rowing has existed along the river in Manchester and Salford since 1823. A regatta was inaugurated on 12 September 1842 on a straight course from Throstle's Nest Weir to Regent Road Bridge. Racing continued in Manchester with events such as Agecroft Regatta and Warburton Regatta. At
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#173277304694210036-476: Is to disperse the fertilised eggs, preferably away from the coast into the relative safety of the open ocean. There the larvae develop as they consume their fat stores, and eventually hatch from the egg capsule into miniature versions of their parents. To survive, they must then become miniature predators themselves, feeding on plankton. Fish eventually encounter others of their own kind ( conspecifics ), where they form aggregations and learn to school. Internally,
10229-698: Is to reinvent the central Manchester conurbation as the major waterfront destination in Northern England." A number of key stakeholders are involved in the development of this regeneration vision. These include Manchester, Salford and Trafford councils, Manchester Ship Canal Company, Environment Agency, Mersey Basin Campaign, local businesses, landowners, community groups and the wider Manchester, Salford and Trafford communities. In 2007 Manchester City Council , Salford City Council and Trafford Metropolitan Borough Council prepared planning guidance to support
10422-570: Is used for recreational activities, such as pleasure cruising, rowing, racing, swimming and fishing. From its source to the confluence with the River Mersey the Irwell is about 39 miles (63 km) long. Rising on the moors above Cliviger near the sources of the Lancashire River Calder and the Yorkshire River Calder , it flows south through Bacup , Rawtenstall , Ramsbottom and Bury before merging with
10615-573: The Manchester Evening News in 1971 stated that Bury Angling Society had signed an agreement with Bury Corporation giving them fishing rights along four miles (six kilometres) of the river between Summerseat and Radcliffe. The secretary of the society was quoted as saying: Extensive tests have been carried out on fish we put in the river and we are satisfied that the water will support fish life. Roach and perch have already been caught and we have had no reports of any ill-effects. There
10808-572: The Celtic tribe, the Brigantes , who farmed the uplands and lower reaches of the river in the late Iron Age . In AD 79 the Roman Empire conquered these tribes, building forts at the confluences of the Irwell and the rivers Irk and Medlock and naming the town Mamucium . They also built a ford with rectangular stone blocks at Cornbrook, which is thought to be the first man-made structure to span
11001-618: The Coral Sea . Forage fish often make great migrations between their spawning, feeding and nursery grounds. Schools of a particular stock usually travel in a triangle between these grounds. For example, one stock of herrings have their spawning ground in southern Norway , their feeding ground in Iceland , and their nursery ground in northern Norway. Wide triangular journeys such as these may be important because forage fish, when feeding, cannot distinguish their own offspring. Capelin are
11194-623: The Manchester Guardian has so rightly called that "melancholy stream"... I have had my differences with the British Field Sports Society, but I have nothing but admiration for the excellent series of reports on river pollution which have been prepared for that Society... and ventured to suggest that they should make a similar survey of the Rivers Irwell and Roach. These two rivers were covered by
11387-625: The Manchester Ship Canal just south of Irlam Locks. At this point the Ship Canal is the canalised section of the River Irwell . The old course of the Mersey has been obliterated by the canal past Hollins Green to Rixton although the old river bed can be seen outside Irlam and at Warburton . At Rixton the River Bollin enters the canal from the south and the Mersey leaves the canal to the north, meandering through Woolston , where
11580-457: The Manchester Ship Canal . In the 17th and 18th centuries, the Irwell's lower reaches were a trading route that became part of the Mersey and Irwell Navigation . In the 19th century, the river's course downstream of Manchester was permanently altered by the construction of the Manchester Ship Canal which opened in 1896. The canal turned Manchester and Salford into a major inland seaport and led to
11773-633: The River Roch near Radcliffe . Turning west, it joins the River Croal near Farnworth before turning southeast through Kearsley , Clifton and the Agecroft area of Pendlebury . It then meanders around Lower Kersal and Lower Broughton . It bisects Salford and Manchester, joining the rivers Irk and Medlock , and then turns west toward Irlam, as part of the Manchester Ship Canal. Its course ends just beyond Irlam Locks, where it empties into
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#173277304694211966-672: The Silver Jubilee Bridge , crosses between Runcorn and Widnes, adjacent to the Runcorn Railway Bridge which opened in 1868. A second road bridge, the Mersey Gateway , opened in October 2017, carrying a six-lane road connecting Runcorn's Central Expressway with Speke Road and Queensway in Widnes. The Mersey Ferry operates between Pier Head in Liverpool and Woodside in Birkenhead and Seacombe , and has become
12159-735: The University of Salford Boat Club since 2004. The boat house, which the sport's governing body, British Rowing , has nominated as the North West Centre of Excellence, also hosts the Two Cities Boat Race, which has been held on the river since 1972. River Mersey The River Mersey ( / ˈ m ɜːr z i / ) is a major river in North West England . Its name derives from Old English and means "boundary river", possibly referring to its having been
12352-513: The Wirral Peninsula to the west, and empties into Liverpool Bay . In total the river flows 69 miles (111 km). Part of the Mersey Railway , a rail tunnel between Birkenhead and Liverpool opened in 1886. Two road tunnels pass under the estuary from Liverpool: the Queensway Tunnel opened in 1934 connecting the city to Birkenhead, and the Kingsway Tunnel , opened in 1971, to Wallasey . A road bridge, completed in 1961 and later named
12545-484: The Woodside ferry terminal in Birkenhead. On the Liverpool side, Liverpool Docks stretch for over 7.5 miles (12.1 km), the largest enclosed interconnected dock system in the world. American author Herman Melville described Liverpool Docks as being comparable to the pyramids in the vast scale of their construction. The docks were built out into the river bed. The Mersey Docks and Harbour Board used granite from
12738-570: The bluegill sunfish in fresh water. Sneaker males that become too large to hide effectively become satellite males . With bluegill sunfish, satellite males mimic the behaviour and colouration of the females. They hover over a nest containing a pair of courting sunfish, and gradually descend to reach the pair just as they spawn. Males may need to be 6 or 7 years old to function capably as parental males, but may be able to function as sneaker or satellite males when they are as young as 2 or 3 years old. The smaller satellite and sneaker males may get mauled by
12931-731: The neolithic period were discovered on Kersal Moor in the late 19th century and early 20th century. There have been isolated finds of artefacts characteristic of this period along the Irwell valley, and a possible hunting site was excavated at Prestwich Golf Course in 1982, which produced a quantity of Late Neolithic and Early Bronze Age flints. Neolithic tools have also been found in the River Roch near Bury and in Radcliffe, and Bronze Age burial sites have been found in Bury and Shuttleworth . The first recorded human settlements were those of
13124-662: The sardine run occurs when millions of sardines migrate from their spawning grounds south of the southern tip of Africa northward along the Eastern Cape coastline. Chinook salmon make the longest freshwater migration of any salmon, over 3,000 kilometres (1,900 mi) up the Yukon River to spawning grounds upstream of Whitehorse , Yukon. Some green sea turtles swim more than 2,600 kilometres (1,600 mi) to reach their spawning grounds. Goldfish , like all cyprinids , are egg-layers. They usually start breeding after
13317-578: The "bleak character" of the Irwell Valley with "many constructions by the river that are decaying and rotting" and said "the main problems are caused by an excess of ammonia and a high organic content from sewage effluents which discharge into the water upstream." The report recommended that "even more support should be given to the NWWA in their pollution control of the River Irwell." Throughout
13510-456: The 1980s, sightings of fish as far downstream as Manchester city centre were reported in local newspapers. In February 1981 the Manchester Evening News reported that "ten jacksharps [sticklebacks], about two inches long" had been spotted by a site manager working on the Mark Addy public house , which was then being built on the disused New Bailey Landing Stage, below New Bailey Street, on the border of Manchester and Salford. Plans for developing
13703-404: The 20-mile (32-kilometre) route from Warrington to Manchester, allowing access to boats of up to 51 tonnes. The waterway, which became known as the Mersey & Irwell Navigation, played a central role in the cotton industry of the 18th century that spearheaded the Industrial Revolution. When Francis Egerton, 3rd Duke of Bridgewater built the Bridgewater Canal , the task of crossing the Irwell
13896-450: The 20th century, with a slow improvement in water quality leading to fresh populations of roach , bream and chub , and sightings of brown trout have become increasingly common. Problems with water quality in some of the former Manchester Docks basins became apparent with the redevelopment of Salford Quays . Years of runoff from sewers and roads had accumulated in the slow running waters of this area and decomposition of organic matter
14089-656: The Beatles . In 1965 it was the subject of the top-ten hit single " Ferry Cross the Mersey " by Gerry and the Pacemakers , and a musical film of the same name . The Liverpool poets published an anthology of their work, The Mersey Sound , in 1967. The river's stretch through Manchester is the main theme in the Stone Roses song "Mersey Paradise", included on the B-side of the 12" version of their 1989 hit " She Bangs
14282-465: The Bridgewater Canal for some years and in 1807 the Irwell and Mersey Navigation Company began to compete with daily services between Runcorn and Manchester . In 1816 they began to use packet steamers. However, in 1830 the Liverpool and Manchester Railway opened; packet boat services went into decline, and ceased to operate completely in the 1860s. In Manchester two other canals used the Irwell as
14475-551: The Drums ", and on their 1992 compilation album Turns into Stone . The Tall ships' fleet has visited the Mersey on four occasions, first in 1984, then in 1992, 2008 and 2012. The traditional song " Leaving of Liverpool " mentions the river in its opening line. The Mersey is considered sacred by British Hindus , and worshipped in a similar way to the River Ganges . Festival of Immersion ceremonies are held annually on
14668-586: The Industrial Revolution factories, mills and terraced hovels grew up along the river banks. Joseph Corbett, the Borough Engineer of Salford, wrote in his 1907 book The River Irwell of his father Edward's experiences around 1819, of seeing "large shoals of fish, chiefly gudgeon but also other fish, rising to the flies" from a vantage point on New Bailey bridge, (now Albert Bridge ) in Manchester. Local industry dumped toxic chemicals into
14861-408: The Industrial Revolution, and it had transformed Manchester into England's third largest port, despite being 40 miles (65 kilometres) inland. As the canal was built, it became clear that Brindley's famous aqueduct would have to be demolished, as it allowed insufficient headroom for the freighters that the canal would carry. Fortunately, in 1896 the councillors of Eccles paid to have the aqueduct moved to
15054-509: The Irwell to burst its banks further downstream in the centre of Manchester. On 2 February 2018 the Environment Agency announced the completion of A£10 million extension to the flood defence scheme which will protect almost 2,000 homes and businesses and has created more than 5 hectares of high quality urban wetland habitat. The new development also provides a new footpath around the site which links to existing footpaths to provide
15247-661: The Irwell, in his book First Impressions: The English People , describing it as: The hapless river—a pretty enough stream a few miles higher up, with trees overhanging its banks, and fringes of green sedge set thick along its edges—loses caste as it gets among the mills and the printworks. There are myriads of dirty things given it to wash, and whole waggon-loads of poisons from dye-houses and bleachyards thrown into it to carry away; steam-boilers discharge into it their seething contents, and drains and sewers their fetid impurities; till at length it rolls on—here between tall dingy walls, there under precipices of red sandstone—considerably less
15440-424: The Irwell, in the vein of Robert Thom 's innovations in hydraulics, in order to provide a more regular supply of water power to mills at a lower cost than steam power. The plan was led by Thomas Ashworth (younger brother of Henry Ashworth ) and Peter Ewart . The proposal was to build 15 reservoirs that would contain 241.3 million cubic feet of water and generate at least 6,600 horsepower . The Irwell Reservoirs Bill
15633-459: The Liverpool banks to New Brighton on the Wirral, forces water to flow faster creating a deep channel along the section of river. For 200 years an admiral was appointed as a conservator to ensure the river remained navigable. Mary Kendrick was the first woman to the post and she had spent years studying a Mersey barrage in the 1980s. Taylor's Bank is a large sandbank extending out to sea on
15826-597: The Mersey Narrows and North Wirral Foreshore, are also Ramsar sites . Capt. William Gill of the Isle of Man Steam Packet Company , charted a safe, navigable channel (the Victoria Channel) through the treacherous uncharted waters of the estuary in 1836. Since the construction of the Manchester Ship Canal, large commercial vessels do not usually navigate the estuary beyond Garston on the north bank, or
16019-480: The Mersey near Flixton . Until the early 19th century the Irwell was well-stocked with fish and other wildlife, with people living near Manchester Cathedral using its water for drinking and other domestic purposes. But during the Industrial Revolution, increasing levels of pollution caused by waste products discharged into the river by local industries proved fatal to wildlife, with fish stocks disappearing completely by about 1850. This situation abated somewhat during
16212-476: The Mersey's tributaries, the River Goyt and the River Bollin . Atlantic grey seals from Liverpool Bay occasionally venture into the estuary along with bottlenose dolphin and harbour porpoise . Otter tracks have been observed near Fiddlers Ferry. Other fish in the estuary include cod , whiting , dab , plaice and flounder . Spiny dogfish , mackerel and tope feed on shrimp and whitebait in
16405-433: The NWWA said that, although the river had a reputation for being polluted, it was getting much better but still had not reached a state where they would be satisfied. She added that tests were being carried out to show the improved cleanliness of the Irwell and that 600 trout had recently been put in the river at Summerseat , near Bury. The proposals were welcomed by both Salford University and Agecroft Rowing Club, with
16598-562: The River Irwell Flood Defence Scheme, the defences help to protect some 3,000 properties in Kersal and Lower Broughton against a 1 in 75 year flood. Concerns have been raised that a 1 in a 100-year flood would breach these defences and cause some £55 million damage to property. The defences proved successful on 22 January 2008, when the worst flooding to hit the region in thirty years caused
16791-437: The River Mersey until the advent of safe passage via bridges and tunnels. Many of these deaths were of people who earned their living on the river, either as mariners or dock workers. The majority of mariners to die worked on the Mersey flat boats and drowned due to the weather conditions or poor craft maintenance, although many ordinary civilians perished too. Another ferry existed at Runcorn Gap and by today's safety standards
16984-655: The Tame and Goyt, in central Stockport , Greater Manchester . However, older definitions, and many older maps, place its start a few miles up the Goyt at Compstall ; for example the 1911 Encyclopædia Britannica states "It is formed by the junction of the Goyt and the Etherow a short distance below Marple in Cheshire on the first-named stream." The 1784 John Stockdale map shows the River Mersey extending to Mottram , and forming
17177-421: The abdomen. Male sharks and rays can pass sperm along a duct into a seminal vesicle , where they store it for a while before it is expelled, while teleosts usually employ separate sperm ducts. Externally, many marine animals, even when spawning, show little sexual dimorphism (difference in body shape or size) or little difference in colouration . Where species are dimorphic, such as sharks or guppies ,
17370-465: The amount of oxygen in the water, which results in less aquatic life and fish. The treatment plant, which was built in the 1930s and last updated in the 1970s, treats waste water from a population of half a million, from Bolton , Prestwich , Whitefield and Clifton . There was another pollution incident in March 2008 when twenty miles of the river turned orange. Iron oxide from old mine workings near
17563-472: The anemone stings. The males do not have to compete with other males, and female anemone fish are typically larger. When a female dies a juvenile (male) anemone fish moves in, and "the resident male then turns into a female and reproductive advantages of the large female–small male combination continue". In other fishes sex changes are reversible. For example, if some gobies are grouped by sex (male or female), some will switch sex. Unisexuality occurs when
17756-399: The appalling conditions were reported in the local and national press consistently for over 40 years. In the early 19th century steam operated ferries were introduced. The Mersey Ferry , managed and operated by Merseytravel , operates between Pier Head in Liverpool and Woodside in Birkenhead and Seacombe . It has become a tourist attraction offering cruises that provide an overview of
17949-420: The approach most commonly used by spawning animals, and is perhaps the "original fish mating system." Common examples are forage fish , such as herrings , which form huge mating shoals in shallow water. The water becomes milky with sperm and the bottom is draped with millions of fertilized eggs. Alternate male strategies which allow small males to engage in cuckoldry can develop in species where spawning
18142-448: The area free from dead embryos and debris. They protect the embryos until they hatch, and often look after the larval stages as well. The time spent guarding can range from a few days to several months. Some guarders build nests ( nest spawners ) and some do not ( substrate spawners ), though the difference between the two groups can be small. Substrate spawners clean off a suitable area of surface suitable for egg laying, and look after
18335-432: The area, but they do not actively build a nest. Bearers are fish that carry their embryos (and sometimes their young) around with them, either externally or internally. Mouth brooders - carry eggs or larvae in their mouth. Mouth brooders can be ovophiles or larvophiles. Ovophile or egg-loving mouth-brooders lay their eggs in a pit, which are sucked up into the mouth of the female. The small number of large eggs hatch in
18528-457: The basin features an inlet to allow the controlled spill of water into the basin when river levels are high. Water will then be stored in the basin during a flood and released back into the river once the water level has dropped. The flood embankments have also been planted with 10 hectares of wildflower habitat, to attract pollinating species such as moths, butterflies and bees. A large urban regeneration project, The Salford Quays Development Plan,
18721-480: The bleak waterway in the heart of Manchester". By 1984 two local men felt the waters were clean enough for them to brave a ten-mile (16 km) charity fund-raising swim from Clifton to Manchester, although they were warned by a spokesman for the North West Water Authority that the cocktail of effluent and occasional untreated sewage meant that the Irwell was still "a class 4 river – top of
18914-612: The border with Manchester. Flooding had been a problem for hundreds of years, and, in 1946, the decision was made to straighten and widen the river to increase its capacity. Work started in 1951 but it was not until September 1970 that water first flowed through the Anaconda Cut. The total cost of the project was £2m. In a question to the House of Commons in 1950 the Member of Parliament for Rossendale, Mr. Anthony Greenwood, highlighted
19107-482: The bottom of the catchment consisting of relatively flat land, which lies between 20 and 150 metres (66 and 492 ft) AOD. The watercourses are characterised by steep narrow valleys, which contributes to high rates of run-off, as does the underlying solid geology. This comprises Lower Coal Measures overlying Millstone Grit , both of which are classified as minor aquifers which will only hold relatively small amounts of water. The surface deposits comprise thick peat in
19300-633: The boundary between Cheshire and Derbyshire . In the west of Stockport it flows at the base of a cliff below the road called Brinksway before reaching flat country. An early Ordnance Survey map indicates the spring at Red Hole on the border of Cheshire and Yorkshire at the head of one of the Etherow's longest headwaters, as being the Source of the River Mersey . From Central Stockport the river flows through or past Heaton Mersey , Didsbury , Northenden , Chorlton-cum-Hardy , Stretford , Sale , Ashton on Mersey , Urmston and Flixton , where it flows into
19493-477: The brooding but cannot handle all the eggs the female produce, such as with some pipefish . The males in some deep sea anglerfishes are much smaller than the females. When they find a female they bite into her skin, releasing an enzyme that digests the skin of their mouth and her body and fusing the pair down to the blood-vessel level. The male then slowly atrophies , losing first his digestive organs, then his brain, heart, and eyes, ending as nothing more than
19686-429: The canal and maintaining its water levels. After 4 miles (6.4 km) it exits the canal, flowing towards Warrington where it widens. It then narrows as it passes between Runcorn and Widnes . The river widens into a large estuary , which is 3 miles (4.8 km) across at its widest point near Ellesmere Port . The course of the river then turns northwards as the estuary narrows between Liverpool and Birkenhead on
19879-475: The cleanest in the UK". The Mersey Valley Countryside Warden Service manages local nature reserves such as Chorlton Ees and Sale Water Park . The river gave its name to Merseybeat , developed by bands from Liverpool, notably the Beatles . In 1965 it was the subject of the top-ten hit single " Ferry Cross the Mersey " by Gerry and the Pacemakers . The name "Mersey" is derived from the Anglo-Saxon mǣres , 'of
20072-404: The decline of the terminal docks at Salford, which closed in 1982. The lower reaches of the Irwell have flooded many times in its history, the most well documented being the floods of 1866, 1946, 1954, 1980, 2007, 2015 and 2020. In December 1816 rapidly thawing snow caused the river to flood, sweeping away a considerable amount of property including building materials and livestock. Locals reported
20265-411: The delivery of a project for the restoration of the river and creation of a new urban park, to be called Irwell City Park . The intention is to develop eight kilometres (five miles) of riverside between The Meadows and Peel Park in the north, through Salford and Manchester city centres, Ordsall and Pomona Dock areas, around to Salford Quays and Trafford Wharfside. The three authorities formally adopted
20458-526: The development of Trafford Park , which became the largest industrial estate in Europe. Further changes were made in the 20th and 21st centuries to prevent flooding in Manchester and Salford, including the construction of the Anaconda Cut in 1970 and the River Irwell Flood Defence Scheme in 2014. The river became severely polluted by industrial waste during the Industrial Revolution , but in
20651-501: The draft Planning Guidance in March 2008. The Guidance sets out the guidelines that the councils will use as a material consideration in determining applications for planning permission and other matters in the Irwell City Park area. It also establishes a set of principles to ensure the provision of a continuous riverside cycle/walkway, and the high quality design of new public open spaces and other infrastructure. An application
20844-476: The eggs. The fungi ( mushrooms ), are also said to "spawn" when they release a white, ‘fibrous’ matter, forming the matrix from-which they grow. There are many variations in the way spawning occurs, depending on sexual differences in anatomy, how the sexes relate to each other, where and how the spawn is released and whether or how the spawn is subsequently guarded. Marine animals, and particularly bony fish , commonly reproduce by broadcast spawning . This
21037-536: The end of the 1980s ambitious plans had been announced to turn Manchester into a top international tourist centre "mainly based on the derelict areas around the waterways of Manchester, Salford and Trafford – the Irwell, the Irk, the ship canal and the Bridgewater Canal ...bringing £500m of investment and 13,000 new jobs over the next 10 years". The Manchester Ship Canal Company also announced
21230-479: The end of the first day, the river had risen 14 feet (4.3 metres) above normal at Peel Park, street lamps could not be lit and mills were brought to a stop. In all, £1 million of property was damaged, 450 hectares of land was flooded, 700 people had to be rescued from wrecked homes, but only one man died by drowning. The height of the flood was marked by an obelisk erected in Peel Park. The construction of
21423-507: The environment. They usually spawn in shoals without complex courtship rituals, and males outnumber females. Broadcast spawners : release their gametes (sperm and eggs) into open water for external fertilisation. There is no subsequent parental care. About 75% of coral species are broadcasters, the majority of which are hermatypic, or reef-building corals. Brood hiders hide their eggs but do not give parental care after they have hidden them. Brood hiders are mostly benthic spawners that bury
21616-434: The estuary is much affected by silting, and part of it is marked on modern maps as dry land rather than tidal. The wetlands are of importance to wildlife, and are listed as a Ramsar site . Most of the conurbation on both sides of the estuary is known as Merseyside . The estuary narrows between Liverpool and Birkenhead , where it is constricted to a width of 0.7 miles (1.1 km), between Albert Dock in Liverpool and
21809-399: The estuary where it meets Liverpool Bay, opened in 1971. The dock deals with around 500,000 containers, over 1.2 million tonnes of oil, over 2.5 million tonnes of grain and animal feed, 452,000 tonnes of wood per year. About 25% of all container traffic between the UK and USA passes through the port making it one of the most successful in the world and known as the "Atlantic Gateway". Liverpool
22002-587: The estuary. For ducks, the estuary is important to common shelducks and Eurasian teal . Waders include redshank , black-tailed godwit , dunlin , pintail and turnstone . The section of the estuary between Runcorn Railway Bridge and Bromborough , including Hale Duck Decoy and Mount Manisty , is designated as a Site of Special Scientific Interest, the SSSI citation describing it as an "internationally important site for wildfowl". There are further SSSIs at New Ferry and Mersey Narrows. The Mersey Estuary, and
22195-490: The event has not returned. During the 1990s the festival was the largest event if its kind in Europe. In the 2010s the event attracted tens of thousands of people and included music stages and other waterside attractions alongside regattas, visiting vessels, and tall ships on the river. Notable musical artists who have performed at the event include Katie Melua , Shola Ama and Russell Watson . Captain David Hawker
22388-403: The existing Silver Jubilee Bridge will also be tolled. Water quality in the Mersey was severely affected by industrialisation, and in 1985, the Mersey Basin Campaign was established to improve water quality and encourage waterside regeneration. In 2002, oxygen levels that could support fish along the entire length were recorded for the first time since industry began on the Mersey. In 2009 it
22581-532: The fertilized eggs. For example, among salmon and trout the female digs a nest with her tail in gravel. These nests are called redds . The female then lays her eggs while the male fertilizes them, while both fish defend the redd if necessary from other members of the same species. Then the female buries the nest, and the nest site is abandoned. In North America, some minnows build nests out of piles of stones rather than dig holes. The minnow males have tubercles on their head and body which they use to help them defend
22774-497: The height of the river to have been almost as great as a more serious flood of 1768. A local public house, the Black Boy , suffered extensive damage as the water caused the rear wall to collapse, a local brewery was flooded with the loss of all its stock, and a Mersey Flat came free of its moorings, hitting Regent Bridge. In 1866, the "year of the great Flood", rain fell for three continuous days commencing on Tuesday 13 November. By
22967-561: The highest in England. Two Sites of Special Scientific Interest (SSSIs) are located close to the banks of the Irwell, near to its confluence with the River Croal at Moses Gate Country Park near Bolton . The first is at Nob End , an 88 800 m site which has been designated because of its biological interest, based on the predominance of flora typical of limestone grassland including some nationally rare herbs and orchids . Nob End
23160-415: The host. The same female may use a number of mussels, and she deposits only one or two yellow, oval eggs into each. Early developmental stages are protected from predation within the body of the mussel. After 3 to 4 weeks larvae swim away from the host to continue life on their own. Guarders protect their eggs and offspring after spawning by practicing parental care (also called brood care ). Parental care
23353-606: The lamentable condition of the Irwell and one of its main tributaries, the River Roch: Today I am afraid that fish in most of those rivers are virtually extinct. Anybody who stands today in the City of Manchester outside the Exchange Station and looks down at the noisome black water which flows beneath him would find it difficult to believe that any fish, or any other living creature, could ever have lived in what
23546-461: The largest industrial estate in Europe, and brought employment to the area for the next eighty years. By the 1960s however, the UK had begun to lose its position as an industrial world power. By the mid-20th century, the UK cotton industry had gone into decline because of low-cost competition from Asian manufacturers. The decline of heavy industry in the area, the increasing size of freight-carrying ships, and competition from road transport, brought about
23739-512: The locks into the ship canal at Eastham . Deep-water channels are maintained to both. Until the early 20th century, commercial traffic bound for further upstream carried cargo in large flat-bottomed sailing barges known as Mersey Flats to Howley Wharf in Warrington and (via the Sankey Canal ) to St Helens . Motor barges delivered to riverside factories at Warrington until at least the 1970s, but nowadays only pleasure craft and yachts use
23932-552: The lower Irwell Valley. Ashclough, a 5.08-hectare (12.6-acre) site which comprises the steep banks of the river between Prestolee and Little Lever , has been designated an SSSI because of its geological interest, primarily because it is the best site in the area displaying the Ashclough marine band and its associated strata. Ashclough is a site of national importance for interpreting the coal measures palaeogeography of Great Britain. The River Irwell catchment area extends from
24125-593: The main river and adjacent salt marshes. The average amount of Hg in the Mersey was found to be 2 mg/kg with the highest amounts of 5 mg/kg occurring below the surface at concentrations harmful to sediment dwelling biota. The vertical rise and fall in Hg pollution observed at four Mersey salt marshes indicated a decline in metal pollution since the 1980s. Salmon have returned to the river and have been seen jumping at Woolston and Howley Weirs between September and November. Salmon parr and smolt have been caught in
24318-470: The male is pregnant, the female starts a new batch of eggs, which are ready at about the same time that the male gives birth to the young from the previous mating. This close timing of development promotes monogamy, especially if the likelihood of encountering another potential mate is low." Polygyny occurs when one male gets exclusive mating rights with multiple females. In polygyny, a large conspicuous male usually defends females from other males or defends
24511-533: The male they want to be their mate. For example, among the cichlid Cyrtocara eucinostomus in Lake Malawi , up to 50,000 large and colourful males display together on a lek four kilometres long. The females, which are mouth brooders, choose which male they want to fertilize their eggs. Polyandry occurs when one female gets exclusive mating rights with multiple males. This happens among fish like clownfish that change their sex. It can also happen when males do
24704-498: The males often have penis-like intromittent organs in the form of a modified fin. A species is semelparous if its individuals spawn only once in their lifetime, and iteroparous if its individuals spawn more than once. The term semelparity comes from the Latin semel , once, and pario , to beget, while iteroparity comes from itero , to repeat, and pario , to beget. Semelparity is sometimes called "big bang" reproduction, since
24897-406: The middle of the range of similarly industrial-urban river-estuaries. The distribution of individual PAH compounds suggests that the Mersey has contaminants mainly derived from combustion sources such as vehicle exhaust as well as coal burning. The distribution of the toxic heavy metal Mercury (Hg) has been assessed by measuring 203 sediments taken from shallow cores (0.4 – 1.6 m) extracted from both
25090-503: The moors above Bacup to the Manchester Ship Canal. The climate of the catchment area is wetter than the UK average, with rainfall of 1,456 millimetres (57.3 in) per annum compared to 1,231 millimetres (48.5 in) per annum, and the rivers quickly respond to rainfall. The topography varies considerably, with the upper reaches dominated by the Pennine moors at an altitude of between 350 and 450 metres (1,150 and 1,480 ft) AOD and
25283-437: The more powerful parental males, but they spawn when they are younger and they do not put energy into parental care. Hermaphroditism occurs when a given individual in a species possesses both male and female reproductive organs, or can alternate between possessing first one, and then the other. Hermaphroditism is common in invertebrates but rare in vertebrates. It can be contrasted with gonochorism , where each individual in
25476-581: The more primitive bony fishes is the assemblage of polyandrous (many males) breeding aggregations in open water and the absence of parental care..." There are two main reproduction methods in fish. The first method is by laying eggs and the second by live-bearing (producing their young alive). Monogamy occurs when one male mates with one female exclusively. This is also called pair spawning . Most fish are not monogamous, and when they are, they often alternate with non-monogamous behaviours. Monogamy can occur when feeding and breeding grounds are small, when it
25669-482: The most encouraging feature of the appalling situation) are hailed with delight as being the purest water which the rivers hold." The full importance of that statement will be realised when I remind hon. Members of the frequency with which residents in Bacup, Ramsbottom, Manchester and Salford are subjected to flooding from the waters of the Irwell. In 1951, it was announced that flood defence works were to be carried out on
25862-434: The mother's mouth, and the fry remain there for a period of time. Fertilization often occurs with the help of egg-spots, which are colorful spots on the anal fin of the male. When the female sees these spots, she tries to pick up the egg-spots, but instead gets sperm that fertilizes the eggs in her mouth. Many cichlids and some labyrinth fish are ovophile mouthbrooders. Larvophile or larvae-loving mouth-brooders lay their eggs on
26055-399: The nest site. Bitterlings have a remarkable reproduction strategy where parents transfer responsibility for the care of their young to mussels . The female extends her ovipositor into the mantle cavity of the mussel and deposits her eggs between the gill filaments. The male then ejects his sperm into the mussel's inhalant water current and fertilization takes place within the gills of
26248-526: The next 120 years and specially designed barges with a shallow draft , known as " Mersey flats ", were used on both waterways. Over the years both trade and rivalry continued to grow with each company offering reduced freight charges or special rates and concessions to gain business from the other. The most important cargo carried was raw cotton from Liverpool to Manchester but timber, dyewoods, pig iron , lead, copper, nails, tar, sand, grain and flour were also carried. Passenger services had been operating on
26441-415: The normal way on the substrate, but in the process accidentally fertilize eggs that the female retains and does not spawn. These eggs are spawned later, usually without allowing much time for embryonic development. The next step in the evolution of livebearing is obligate (by necessity) internal bearing, where the female retains all the embryos. "The only source of nutrition for these embryos, however,
26634-448: The north side of the channel entrance to the river on which many ships have come to grief over the years. Historically the lowest bridging point on the Mersey was at Warrington where there has been a bridge since medieval times. The first ferry across the estuary was introduced in medieval times by monks from Birkenhead Priory . They transported travellers or accommodated them at the priory in bad weather. Countless people died on
26827-526: The number of fish in the river and "massively improve the environment locally so walkers, canoeists and anglers will all reap the benefits." The company said that this was to be the biggest scheme that they had undertaken in the region, and the project manager was quoted as saying: Reducing the amount of phosphate in the water is the main driver behind the scheme. New legislation states that the amount of phosphate in waste water should be one milligram per litre because it causes water to clog with algae and reduces
27020-408: The original river channel became Warrington Dock (Walton Lock) in the ship canal. In the 1960s, the former river channel was filled. The area is now Wilderspool Causeway Park. At the western end of the canalised section in Warrington is the old entrance to the former Runcorn to Latchford Canal . This waterway was abandoned with the construction of the ship canal. It was constructed because the Mersey
27213-582: The pollution chart". During 1985 the Croal–Irwell Valley local plan was launched, listing 187 proposals for the improvement of the valley and in 1986 the Mersey Basin Campaign was announced. The campaign was to cover a large area, from Rossendale in the north to Crewe in the south, and it was promised that £67m would be made available in the first three years for water- and land-based projects. In September 1987 plans were revealed for
27406-433: The pollution in the water. Although the river there is now a great deal better than it has been for 100 years, fish will probably not be able to live long. These had probably got into the main river from small streams flowing into the Irwell. But I think it is real progress. Mr Harper went on to say that the Irwell had been well stocked with fish along its whole length 100 years ago but refused to guess when it would reach
27599-429: The public are cordially invited back onto her waters." During 1994, construction work began on a new £1.3M footbridge to link Manchester and Salford, to be known as Trinity Bridge . The box-girder and steel cable construction was designed by Spanish architect Santiago Calatrava to represent a ship in full sail as the centrepiece of the £50M Chapel Wharf Regeneration Scheme, which was expected to breathe new life into
27792-458: The right shows the main spawning grounds and larval drift routes. Capelin on the way to feeding grounds is coloured green, capelin on the way back is blue, and the breeding grounds are red. In a paper published in 2009, researchers from Iceland recount their application of an interacting particle model to the capelin stock around Iceland, successfully predicting the spawning migration route for 2008. Referred to as "the greatest shoal on earth",
27985-528: The river Meteia meaning "reaping one" or "she that cuts down" (Breeze notes the possibility of a local deity associated with the river, but highlights that this is only a supposition based on known deities like Sulis and Aerfen ) . The Mersey is formed from three tributaries : the River Etherow , the River Goyt and the River Tame . The modern accepted start of the Mersey is at the confluence of
28178-403: The river Roch. At Bacup the headwater of the Irwell is discoloured by ochre deposits from a disused mine but work is being done to stop the ochre seepage. Fish do exist in the stretch between Rossendale and Bury and fish are to be introduced in stretches between Radcliffe and Manchester. However, it is feared that it will be many years before fish will be able to breed freely in the river. In 1980,
28371-407: The river and surrounding areas. The Mersey Railway completed its tunnel through the estuary's underlying Triassic sandstone using manual labour in 1885. Intended as a pneumatic railway , the company opted for steam trains from its opening until it was electrified in 1903. The centre of the running tunnel is between 30 feet (9.1 m) and 70 feet (21.3 m) below the river bed. The railway
28564-636: The river as fish such as perch , barbel , grayling , carp , roach , chub , trout , pike , bream and dace have been caught. Warrington Anglers Association have fishing rights on a large stretch of the River through most of Warrington. Prince Albert Angling Society also have a small stretch near Rixton. The river has also faced problems regarding the poaching of fish despite a strict 'catch and release' policy imposed on anglers for ecological reasons which applies to most UK waterways. The Mersey River Festival, rebranded in 2018 as ‘River Festival Liverpool’,
28757-498: The river between Stockport and Carrington. Liverpool Sailing Club located at Garston Coastal Park on the north bank of the estuary has a 1000 feet slipway giving access to river for water sports. The wooded suburban stretch of the river from above Howley Weir to Woolston is also used for recreational and competitive rowing, operated from the Warrington Rowing Club. Angling has become popular on some stretches of
28950-679: The river for recreational use were also coming to fruition as it was reported in 1982 that, over the May bank holiday , the first pleasure cruise on the river in the 20th century would leave from the Mark Addy as part of a three-day experiment to see whether river cruises could be a success. In 1983 over 100 canal and river boats rode the flooded river for the Greater Manchester Waterways Festival, an event aimed at demonstrating how pleasure boating could "transform
29143-439: The river from its cradle in the moors to its grave in the Manchester Ship Canal." The second quotation is one which I find still more appalling than the first. It is: "There are no fish in these rivers (apart from a very occasional tributary), no insects, no weeds, no life of any kind except sewage fungus, nothing but chemicals and any dirt which cannot be put to profitable use. Sewage effluents (and, being usually very good, they are
29336-601: The river, in which clay figures representing the Hindu Lord Ganesha , the elephant deity riding a mouse, are submerged in the river from a ferry boat. Followers throw flowers, pictures and coins into the river. From its lowest point, moving upstream, confluences and tributaries of the Mersey catchment include: Spawn (biology) As a general rule, aquatic or semiaquatic reptiles , birds , and mammals do not reproduce through spawning, but rather through copulation like their terrestrial counterparts. This
29529-459: The river, such as gas-tar, gas-lime and ammonia water, and by 1850 fish stocks had all but disappeared. In 1860 the Irwell was described as "almost proverbial for the foulness of its waters; receiving the refuse of cotton factories, coal mines, print works, bleach works, dye works, chemical works, paper works, almost every kind of industry." In 1862 the Scottish geologist Hugh Miller wrote about
29722-731: The river. For four hundred years the Pax Romana brought peace, but their withdrawal in AD 410 left the tribes at the mercy of the Saxons , who renamed the town Manigceastre. The Danes later seized, and all-but destroyed Manigceastre, and absorbed what was left of the tribes. The Danelaw ruled until AD 920 when the Norsemen were expelled by Edward the Elder . In the Middle Ages the town, which
29915-519: The river. The Manchester Ship Canal near Salford Quays is one of the top ten sites in Britain for diving ducks, providing a winter home to approximately 3,000 common pochard and 2,000 tufted ducks . From its source until shortly after its confluence with the River Croal, the river runs through a landscape formed from rocks of the late Carboniferous Coal Measures and the underlying (and therefore older) Millstone Grit , consisting mostly of
30108-567: The same state again. In 1974 all of the river authorities were merged into the Regional Water Authorities. In the 1974 annual report of the North West Water Authority (NWWA) , it was said that the river "once internationally famous, or infamous as the epitome of river pollution, is now in a much better state as compared with its condition at the time of a special survey carried out nine years ago." This
30301-401: The second half of the 20th century a number of initiatives were implemented to improve water quality, restock it with fish and create a diverse environment for wildlife. Stretches of the river flowing through Manchester and Salford have attracted large-scale investment in business and residential developments, such as Salford Quays, and other parts have become important wildlife havens. The Irwell
30494-412: The sexes of most marine animals can be determined by looking at the gonads . For example, male testes of spawning fish are smooth and white and account for up to 12% of the mass of the fish, while female ovaries are granular and orange or yellow, accounting for up to 70% of the fish's mass. Male lampreys, hagfish and salmon discharge their sperm into the body cavity where it is expelled through pores in
30687-504: The ship canal company's dredgings have formed the Woolston Eyes nature reserve, and on to Warrington . During the construction of the Manchester Ship Canal, the original course of the river through Wilderspool (which is north of Stockton Heath and Lower Walton) was diverted westward into a canalised section. Wilderspool Causeway remains the only remnant of the original eastern bank of the Mersey at this point in Warrington. Part of
30880-425: The ship canal is said to have reduced the risk of flooding, by providing a larger outlet below Regent bridge. In 1946 in Salford 5,300 properties were flooded, and 600 were flooded in 1954. To alleviate such problems two flood storage basins with a capacity of 650,000 cubic metres (850,000 cu yd) have been constructed to the west of Littleton Road, Kersal, at a cost of around £11 million. As part of
31073-415: The ship canal, a lock bypassing Howley Weir allowed navigation further upstream via a straight "cut" avoiding a meander around Woolston. The Mersey Valley Countryside Warden Service manages local nature reserves such as Chorlton Ees and Sale Water Park recreational sites and provides an educational service along the Mersey from Manchester to the Manchester Ship Canal. It is possible to canoe on parts of
31266-482: The single reproductive event of semelparous organisms is usually large and fatal to the spawners. The classic example of a semelparous animal is the Pacific salmon , which lives for many years in the ocean before swimming to the freshwater stream of its birth, spawning, and then dying. Other spawning animals which are semelparous include mayflies , squid , octopus , smelt , capelin and some amphibians. Semelparity
31459-439: The source at Irwell Springs had polluted the water since 1969 and in 1997 a Coal Authority survey identified the stretch as having the fourth worst case of minewater pollution in the country. A treatment plant was built in 1999 to remove the pollution at a cost of £1M; however, it is thought that there was a collapse in the mine after heavy rains in the spring of 2008. Although the water was stained with ochre , no damage to wildlife
31652-467: The spot it occupies today, alongside the canal. The Bridgewater Canal is now carried over the Manchester Ship Canal by the equally celebrated Barton Swing Aqueduct , which was completed in 1893 with the novel idea of "opening" by rotating 90 degrees to allow ships to pass. The construction of the Manchester Ship Canal and the Manchester Docks led to the development of Trafford Park as
31845-427: The standard, large, hook-nosed males and that spawn by sneaking into a redd (spawning nest) to release sperm simultaneously with a mated pair. This behaviour is an evolutionarily stable strategy for reproduction, because it is favoured by natural selection just like the "standard" strategy of large males. Cuckoldry occurs in many fish species, including dragonets , parrotfishes and wrasses on tropical reefs and
32038-482: The stretch of the river passing through Lower Broughton between Cromwell Bridge and Gerald Road Bridge, although local property owners and shopkeepers were outraged at being asked to bear part of the cost. Work on the 8-foot-thick (2.4 m) concrete wall did not get underway until June 1952 and was still only nearing completion when, in August 1957, nearby homes were threatened by flooding during heavy rain. A report in
32231-444: The third report; and very sorry reading it made. There are two passages in that report which I should like to read. The first says: "The banks are lined with factories, large and small, many of which take their water from the drainage of the hills forming the slopes of the river's valley, and discharge it as a polluted effluent, either into the small feeders, or the main river itself, so it may be said that no natural water normally enters
32424-480: The turn of the 20th century, rowing was very popular in the area with many local clubs such as Nemesis, Prince of Wales, Minerva, Didsbury and Agecroft all competing regularly. With the decline in the condition of the water, by the Second World War only Agecroft and Broughton rowing clubs were still active. Agecroft Rowing Club was formed in 1861, making it one of the oldest open membership rowing clubs in
32617-425: The university stating that they wished to use that section for their boat race. Later that year it was reported that hundreds of trees and shrubs were to be planted along the banks of the Irwell between Broughton and Pomona Dock in a £650,000 "green finger" scheme to "bring the countryside into the heart of industrial Salford". The dossier outlining the scheme, prepared by Salford's Technical Services Officer, emphasised
32810-427: The upper estuary and the tidal river where a number of sailing clubs are based. On most high tides, seagoing yachts with masts raised can navigate as far upstream as Fiddlers Ferry – about 3.1 mi (5.0 km) downstream of Warrington – where there is a small marina accessed via a river lock. Although river craft can continue upstream to Howley Weir, there are no landing or mooring facilities. Before construction of
33003-407: The upper reaches, with glacial boulder clay and glacial sand and gravel in the lower parts. The sand and gravel are also classified as a minor aquifer, whilst the boulder clay is a non-aquifer. The higher, steeper slopes of the upper part of the catchment provide a large source of erodible material and debris which is transported downstream to the lower, flatter parts of the catchment. Where the channel
33196-499: The weir and the lock is known locally as "Monkey Island". West of Warrington the river widens, and then narrows as it passes through the Runcorn Gap between the towns of Runcorn and Widnes , in Halton . The Manchester Ship Canal passes through the gap to the south of the river. The gap is bridged by the Silver Jubilee Bridge and Runcorn Railway Bridge . Another crossing, the Mersey Gateway road bridge opened in October 2017, and
33389-492: The world. The club was originally based in the grounds of Agecroft Hall and then a short distance downstream at Littleton Road. However, the river became impossible for eight's and fours to pass due to the encroachment of weeds and river life following the clean up of the environment. The club now operates from a boat house next to the Salford Watersports Centre at Salford Quays , which it has shared with
33582-501: Was an annual event held on the river Mersey during a weekend in May or June between 1981 and 2019 to celebrate Liverpool's maritime tradition. Originally organised by the Merseyside Development Corporation , the festival was later overseen by Liverpool City Council and Culture Liverpool. The last event was planned to take place between the 8 and 10 May 2020, but was cancelled due to COVID . As of 2024,
33775-631: Was announced by United Utilities . The improvements included fitting filters on sewers in Lower Broughton to ensure litter was not washed into the river, as part of a scheme to improve overflows across Adlington , Wigan , Chorley , Rochdale and Bury. Then in October 2008 United Utilities announced that work on the Ringley Fold Wastewater Works in Stoneclough, to be completed by the end of the year, should increase
33968-509: Was announced that the river is "cleaner than at any time since the industrial revolution" and is "now considered one of the cleanest [rivers] in the UK". Persistent organic and mercury (Hg) pollution contained within sediments of the Mersey estuary have been evaluated by British Geological Survey . Mersey river sediments from outer to inner estuary (Alfred Dock to Widnes) contain a variety of common organic pollutants, including polyaromatic hydrocarbons (PAH) with concentrations which fall in
34161-406: Was at the time the largest cheque ever written, and the building of the Manchester Ship Canal began. The canal, which was made by greatly deepening and widening the eastern section of the Mersey and Irwell Navigation, opened on 1 January 1894. It reduced the shipping costs of raw cotton to the mills and the dispatching the finished cloth overseas. The canal had helped the region to become the centre of
34354-414: Was causing oxygen depletion . In 2001, a compressed air injection system was introduced. This raised the oxygen levels in the water by up to 300%, improving the water quality to such an extent that the number of invertebrate species present increased to more than 30, including freshwater shrimp. Spawning and growth rates of fish species such as roach and perch have also increased, and are now amongst
34547-401: Was formed. Local authorities were ordered to provide sewage treatment facilities, and industrial concerns were told to use the best practical means of preventing pollution. Salford was one of the first authorities in the Irwell watershed to install intercepting sewers and sewage treatment works at Mode Wheel Sewage works. In the 1830s, there was an ambitious plan to build a reservoir system on
34740-402: Was highly dangerous. Passengers had to traverse wooden planks over the mud flats to reach the ferry boats which themselves were often poorly maintained and leaking. Even the steps down to the river bank were described as "beautifully slippery". In the dark the ferry was particularly worrying as there were few or no lights and the journey was only undertaken on a "needs must" basis. Complaints about
34933-674: Was in difficulty in the river, the cry would go up "Bring Mark Addy!" and he would race to the rescue. He was awarded a number of medals including the gold and silver medals from the Humane Society for the Hundred of Salford , and the Royal Humane Society 's bronze medal. In 1878 he became the only civilian ever to be awarded the Albert Medal (first class) , His final rescue was on Whit Monday in 1889, when he saved
35126-458: Was likely a corruption of the actual name . Some, including David Parsons, have suggested the original forms "Segeia" and "Segantii" - based on the root "sego" meaning "strong" . Andrew Breeze instead suggests the original forms "Meteia" and "Metantii" - from "met" meaning "cut" or "harvest" - with the likely meaning being that the Metantii were "reapers (of men), cutters-down (of enemies)", with
35319-542: Was now known as Manceastre (later to become Manchester), grew and prospered, and trading vessels plied along the river. The hamlet of Kersal, which now forms part of the City of Salford, was gifted to the Cluniac Priory of Lenton , near Nottingham , in 1142. The most important part of the gift was the fishing rights on the River Irwell, and even in the 18th century, the salmon rights on the rivers of Lancashire were let every year for many hundreds of pounds. During
35512-401: Was one of the main obstacles he faced. The solution was to build a canal-carrying bridge across the river, the first barge aqueduct in England. The aqueduct, which opened in 1761, measured 12 metres (39 ft) high and 200 metres (656 ft) long, and became one of the wonders of the age. The Mersey and Irwell Navigation and the Bridgewater Canal competed for trade to and from Manchester for
35705-478: Was passed and this board disappeared to be replaced by the Mersey River Board, which was replaced in turn by the Mersey and Weaver River Authority in 1965. During a 1950s television documentary entitled River of Irwell, the watercourse was described as "The hardest worked river in the world". In 1946, there was serious flooding in Salford, caused by a bottleneck at a bend in the river at Strangeways, on
35898-487: Was published in 1985 and work began a few years later to redevelop the site for residential, business and leisure purposes. The Salford Quays waterside development has made living by the Irwell, and the Manchester Ship Canal into which it flows, fashionable once again. There are further plans to "turn the tide on the years of neglect and once again embrace the River Irwell as a fundamental part of Manchester and Salford's heritage and future economic and social growth. The vision
36091-642: Was reported in an article in The Manchester Evening News on 26 October of that year which stated that: During nine years of pollution control work reviewed by the North West Water Authority, the biggest improvement had been in the Bolton District, where effluent from five dilapidated sewage plants and two paper mills were now being treated at the Ringley Fold Works [but] there has been little reduction in pollution from
36284-484: Was reported. In the late 17th century, the Warrington businessman Thomas Patten had made the River Mersey navigable as far as Warrington and suggested that there would be significant commercial value in extending this along the Irwell as far as Manchester. In 1721, Parliament authorised the alteration with the Mersey and Irwell Navigation Act, and by 1736 work had been completed by creating eight canal locks along
36477-469: Was submitted to Parliament in November 1832, but it was not passed. The reasons are not entirely known, but are seemingly related to concerns from mill owners about unequal benefits obtained from the plan. One of the most famous characters associated with the river during this time was Mark Addy , who was born in a tenement on The Parsonage near Blackfriars Bridge in Manchester in 1838. Whenever anyone
36670-535: Was the Mersey River Festival's official artist from the late 1990s until the last event in 2019. The painter attended annually to capture on paper the boats, attractions, visitors, and events as they unfolded. Proposals continue for the construction of the Mersey Barrage , a tidal scheme to generate electricity and create another crossing of the river. Very high spring tides can generate
36863-522: Was the first UK port with radar assisted operations. The river empties into Liverpool Bay on the Irish Sea , after a total course of 69 miles (111 km). From 4 metres (13.1 ft) neap tide to 10 metres (32.8 ft) spring tide , the River Mersey has the second highest tidal range in Britain – second only to the River Severn . The narrows in the river estuary between Dingle Point on
37056-580: Was the longest motorway bridge in England. A second viaduct alongside opened in 1995; northbound traffic uses the old viaduct and southbound the new. A new 6-lane bridge, the " Mersey Gateway ", between Runcorn and Widnes began its construction phase in May 2014 and opened just after midnight on 14 October 2017. At the same time the Silver Jubilee Bridge was closed to undergo maintenance for approximately 6–12 months, but will remain open to pedestrians and cyclists. The new bridge uses tolls and
37249-548: Was thought to be ovoviviparous until it was shown in 2001 that the embryos received nutrients from the mother. Spawning grounds are the areas of water where aquatic animals spawn, or produce their eggs. After spawning, the spawn may or may not drift to new grounds which become their nursery grounds. Many species undertake migrations each year, and sometimes great migrations, to reach their spawning grounds. For example, lakes and river watersheds can be major spawning grounds for anadromous fish such as salmon . These days, it
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