Misplaced Pages

#480519

51-402: The Wolford Mountain recreation area offers lake and stream fishing, boat rentals, boat ramps, picnic areas, and 48 campsites. The reservoir is stocked with trout and kokanee salmon . The tailwater section of Muddy Creek below the dam offers rainbow and brown trout fishing on publicly accessible lands. The Colorado River District revealed in early 2015 that there are some structural problems with

102-406: A chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinctions . Local extinctions mark a change in the ecology of an area. It has sometimes been followed by a replacement of the species taken from other locations, such as with wolf reintroduction . Glaciation is one factor that leads to local extinction. This was the case during

153-574: A drying pond or an entire ocean, it can be said to be extirpated or locally extinct in that pond or ocean. A particular total world population can be more or less arbitrarily divided into 'stocks' or 'subpopulations', defined by political or other geographical delimitations. For example, the Cetacean Specialist Group of the International Union for Conservation of Nature (IUCN) has assessed the conservation status of

204-487: A female or for longevity on the spawning grounds. Sockeye salmon with longer and more difficult migration routes produce fewer eggs on the spawning grounds. High water temperatures also increase the energy expenditure of sockeye salmon as they migrate upriver. Aggressive behavior displayed by dominant males is predominantly directed towards intruding dominant males. Sometimes sockeye salmon males behave aggressively towards subordinate males. These encounters are short, with

255-700: A habitat. Stranding is when salmon swim into dry land or shallow water during their migration for spawning and die from suffocation. In fact, studies show that the sockeye salmon with the largest bodies are most susceptible to stranding mortality.   Reproduction is marked by depletion in energy stores. Fat, protein, and somatic energy stores decrease from the final moments in marine migration through freshwater entry, spawning, and death. Sockeye salmon do not feed during reproduction. Feeding ends once they enter into freshwater, which can be several months before spawning. Embryos are maintained with only endogenous food supplies for about 3–8 months. Reproduction in

306-728: A landlocked variety termed black kokanee, or " kunimasu " in Japanese, was deemed to be extinct after 1940, when a hydroelectric project made its native lake in northern Akita Prefecture more acidic. The species seems to have been saved by transferring eggs to Saiko Lake , 500 kilometers to the south, however. This fish has been treated as a subspecies of sockeye Oncorhynchus nerka kawamurae , or even an independent species Oncorhynchus kawamurae . Sockeye salmon use patterns of limnetic feeding behavior, which encompasses vertical movement, schooling , diel feeding chronology , and zooplankton prey selectivity. They can change their position in

357-628: A region as the ecosystem matures and reaches a climax community . A local extinction can be useful for research: in the case of the bay checkerspot butterfly , scientists, including Paul R. Ehrlich , chose not to intervene as a population disappeared from an area in order to study the process. Many crocodilian species have experienced localized extinction, particularly the saltwater crocodile ( Crocodylus porosus ), which has been extirpated from Vietnam, Thailand, Java, and many other areas. Major environmental events, such as volcanic eruptions, may lead to large numbers of local extinctions, such as with

408-410: A species has an intrinsic extinction-ability (incidence function). Some species exploit or require transient or disturbed habitats, such as vernal pools, a human gut, or burnt woodland after forest fires , and are characterised by highly fluctuating population numbers and shifting distributional patterns. Many natural ecosystems cycle through a standard succession , pioneer species disappear from

459-631: A species that have been reintroduced into parts of their historical range. This has happened with red wolves ( Canis rufus ) in the United States in the late 1980s and also grey wolves in Yellowstone National Park in the mid-1990s. There have been talks of reintroducing wolves in Scotland, Japan, and Mexico. When the local population of a certain species disappears from a certain geographical delimitation, whether fish in

510-841: A spot on their tail or back. Sockeye salmon range as far south as the Columbia River in the eastern Pacific (although individuals have been spotted as far south as the 10 Mile River on the Mendocino Coast of California ) and in northern Hokkaidō Island in Japan in the western Pacific. They range as far north as the Bathurst Inlet in the Canadian Arctic in the east and the Anadyr River in Siberia in

561-753: A subordinate male will move quickly into the redd and release their sperm. Nearby dominant males from other redds will also do this. Male social status is positively correlated to length and dorsal hump size. Larger females tend to spawn in shallower water, which is preferred over deeper water. There is a dramatic sexual dimorphism at maturity. Males go through numerous morphological changes at maturation including, an increase in body depth, hump height, and snout length. Snout size also increases in females, but hump height and adipose fin length do not increase. This could mean that longer snout sizes are sexually selected, but hump height and adipose fin length are not. Females develop large gonads that are about 25% of

SECTION 10

#1732788020481

612-436: Is determined by the number of eggs she lays, her body size, and the survival of the eggs, which is due in part to the quality of the nest environment. Male spatial distribution depends on shifts in reproductive opportunities, physical traits of breeding sites, as well as the operational sex ratio (OSR) of the environment. Non-dominant males adopt a subordinate behavior, acting as a satellite to mated pairs. During spawning,

663-952: Is red-fish name in the Sinixt Interior Salish language and silver trout in the Okanagan language . They are much smaller than the anadromous variety and are rarely over 35 cm (14 in) long. In the Okanagan Lake and many others, there are two kinds of kokanee populations – one spawns in streams and the other near lake shores. Landlocked populations occur in the Yukon Territory and British Columbia in Canada , as well as, in Alaska , Washington , Oregon , California , New York , Utah , Idaho , Montana , Nevada , Colorado , New Mexico , and Wyoming in

714-514: Is sometimes called red or blueback salmon, due to its color. Sockeye are blue tinged with silver in color while living in the ocean. When they return to spawning grounds, their bodies become red and their heads turn green. Sockeye can be anywhere from 60 to 84 cm (2 ft 0 in – 2 ft 9 in) in length and weigh from 2.3 to 7 kg (5–15 lb). Two distinguishing features are their long, serrated gill rakers that range from 30 to 40 in number, and their lack of

765-456: Is the usual color of females. Even small changes in wavelength , saturation , and brightness can affect preference. Some traits that lead to reproductive success, such as body size and sexual dimorphism can affect one's survival. This leads to opposing pressures of natural selection and sexual selection . Larger males are favored, unless the risk of predation is very high. Sockeye salmon that die prematurely from predation are typically

816-576: Is under review by Fisheries and Oceans Canada as part of its Wild Salmon Policy strategy to standardize monitoring of wild salmon status. Salmon runs of particular note are the Skeena and Nass river runs, and the most famous is the Fraser River sockeye run. The Fraser River salmon run has experienced declines in productivity since the 1990s, mirroring a similar decline in the 1960s. The return abundance (population) of Fraser River sockeye in 2009

867-467: Is when species emphasize their differences in diet and habitat to avoid competition. Interspecific competition can affect the growth rates of the salmon if their access to resources is limited. The total registered fisheries harvest of the sockeye in 2010 was some 170,000 tonnes , of which 115,000 tonnes were from the United States and the rest was equally divided between Canada and Russia. This corresponds to some 65 million fish in all, and to some 19% of

918-421: The 1980 Mount St. Helens eruption , which led to a fern spike extinction. Heat waves can lead to local extinction. In New Zealand, during the summer of 2017–2018, sea surface temperatures around parts of South Island exceeded 23 °C (73 °F), which was well above normal. Air temperatures were also high, exceeding 30 °C (86 °F). These high temperatures, coupled with small wave height, led to

969-732: The Black Sea stock of harbour porpoise ( Phocoena phocoena ) that touches six countries, and COSEWIC , which only assesses the conservation status of wildlife in Canada, even assesses Canadian species that occur in the United States or other countries. While the IUCN mostly only assesses the global conservation status of species or subspecies, in some older cases it also assessed the risks to certain stocks and populations, in some cases these populations may be genetically distinct. In all, 119 stocks or subpopulations across 69 species had been assessed by

1020-658: The Greek ὄγκος (onkos) meaning "barb", and ῥύγχος (rhynchos) meaning "snout". Nerka is the Russian name for the anadromous form. The name "sockeye" is an anglicization of suk-kegh (sθə́qəy̓), its name in Halkomelem , the language of the indigenous people along the lower reaches of the Fraser River (one of British Columbia 's many native Coast Salish languages ). Suk-kegh means "red fish". The sockeye salmon

1071-980: The Kamchatka Peninsula of the Russian Far East , especially on the Ozernaya River of the Kurile Lake , which accounts for nearly 90% of all Asian sockeye salmon production, and is recognized as the largest spawning ground outside of Alaska. Illegal fishing in Kamchatka is subject to environmental concern. Sockeye is almost never farmed. A facility in Langley, BC harvested its first salmon in March 2013, and continues to harvest farmed salmon from its inland facility. United States sockeye salmon populations are currently listed under

SECTION 20

#1732788020481

1122-610: The Pleistocene glaciation event in North America. During this period, most of the native North American species of earthworm were killed in places covered by glaciation. This left them open for colonization by European earthworms brought over in soil from Europe. Species naturally become extirpated from islands over time. The number of species an island can support is limited by its geographical size. Because many islands were relatively recently formed due to climate change at

1173-700: The United States . Nantahala Lake is the only place in North Carolina where kokanee salmon are found. The fish, which is native to western North America, was stocked in Nantahala Lake in the mid-1960s by the NC Wildlife Resources Commission in an attempt to establish the species as a forage fish for other predator fishes in the lake. This stock has remained and become a favorite target for anglers. In Japan,

1224-428: The fry typically rear in lakes before migrating to the ocean. Males partake in competitive and sneaking tactics, formation of hierarchies , and non-hierarchical groupings around females who are ready to mate. Reproductive success varies more in males than females. The greater variability in male reproduction is associated with the greater average size and exaggerated shape of males. Reproductive success in females

1275-421: The ocean , over distances of up to 1,600 km (1,000 mi). Their diet consists primarily of zooplankton . Sockeye salmon are semelparous , dying after they spawn . Some populations, referred to as kokanee , do not migrate to the ocean and live their entire lives in fresh water. The sockeye salmon is the third-most common Pacific salmon species, after pink and chum salmon . Oncorhynchus comes from

1326-485: The Chilko River and Weaver Creek did not show any differences in force-frequency response of the heart or cardiac pumping capacity when reared in common garden temperatures at 5 °C and 14 °C. Therefore, the physiology underlying these differences in thermal tolerance has yet to be determined. Extirpated Local extinction , also extirpation , is the termination of a species (or other taxon ) in

1377-424: The Fraser River and its tributaries in 2010. In total, approximately 11,591,000 Fraser sockeye were caught by Canadian fishers and 1,974,000 Fraser sockeye were caught by American fishers. The final projected escapement (fish which were not caught) was 15,852,990 fish. Recent unpredictable fluctuations in runs are speculated to be due to changing water temperatures. There is high variation in thermal tolerance among

1428-413: The Fraser River, marine environmental conditions, aquaculture, predators, diseases, water temperature and other factors that may have affected the ability of sockeye salmon to reach traditional spawning grounds or reach the ocean." During the commission, hundreds of thousands of documents and scientific research papers were reviewed. Twelve technical reports were published using that information, looking at

1479-1192: The US Endangered Species Act by the National Marine Fisheries Service as an endangered species in the Snake River and as a threatened species in Lake Ozette , Washington. The Snake River sockeye salmon was listed as endangered in November 1991, after the Shoshone - Bannock Tribe at Fort Hall Indian Reservation petitioned the National Marine Fisheries Service. Sockeye is an exception to 2010's forecast resurgence of Oregonian fish stocks. Spring Chinook , summer steelhead , and Coho are forecast to increase by up to 100% over 2008 populations. The sockeye population peaked at over 200,000 in 2008 and were forecast to decline to just over 100,000 in 2010. As an early indication of

1530-603: The ability to bury eggs deeper and provide more protection. Females vary their breeding rate depending on the size of the courting male, mating more quickly with larger males. This increases the likelihood that larger males will displace attending, smaller males. Male sockeye salmon social status and greater reproductivity are directly associated with larger body size and more extreme body shapes; Larger bodies provide males with advantages when it comes to intrasexual competition and being selected for by females during reproduction. Males preferentially spawn with females who are red, which

1581-538: The body mass. Females are responsible for parental care. They select, prepare, and defend a nest site until they die or are displaced. Males do not participate in parental care at all, and they move between females after egg deposition. Sexual selection favors large males and females. Males choose females based on their readiness to spawn and their size in order to maximize their breeding opportunities. Larger bodies allow females to reproduce larger and more numerous eggs, better nest choice and ability to defend it, and

Wolford Mountain Reservoir - Misplaced Pages Continue

1632-643: The dam's worsening condition. Sockeye salmon The sockeye salmon ( Oncorhynchus nerka ), also called red salmon , kokanee salmon , blueback salmon , or simply sockeye , is an anadromous species of salmon found in the Northern Pacific Ocean and rivers discharging into it. This species is a Pacific salmon that is primarily red in hue during spawning. They can grow up to 84 cm (2 ft 9 in) in length and weigh 2.3 to 7 kg (5–15 lb). Juveniles remain in freshwater until they are ready to migrate to

1683-400: The dam, specifically settling and movement of the earthen dam structure. The Ritschard Dam, as it is called, is 122 feet in height and 1,910 feet wide. The dam has also moved horizontally. In 2016 Colorado River District officials and consulted experts determined that the dam is safe and does not require extensive rehabilitation. In late 2020, a comprehensive dam safety evaluation prepared by

1734-417: The different sockeye salmon populations that migrate up the Fraser River. The Chilko River sockeye salmon population is able to maintain cardiorespiratory function at higher temperatures, which may make them more resilient to the effects of rising river temperatures. In one study examining possible physiological mechanisms underlying these population differences in thermal tolerance, juvenile sockeye salmon from

1785-753: The end of the Pleistocene when the sea level rose, and these islands most likely had the same complement of species as found on the mainland, counting the species which still survive at present on a statistically large enough amount of islands will give the parameters with which certain groups of species such as plants or birds will become less biodiverse on a given island over a given period of time, depending on its size. The same calculations can also be applied to determine when species will disappear from nature parks ('islands' in many senses), mountain tops and mesas (see sky islands ), forest remnants or other such distributional patches. This research also demonstrates that certain species are more prone to extinction than others,

1836-423: The firm HDR Engineering for Colorado's Division of Water Resources indicated that the dam's risk of internal erosion from cracking had increased since the 2016 evaluation. The earlier report found a one in one billion chance of the dam failing in any given year, but the 2020 evaluation put the risk of a dam failure at 1.5 in 10,000. The Colorado River Water Conservation District has engaged HDR Engineering to deal with

1887-706: The harvest of all Pacific salmon species by weight. Commercial fishermen in Alaska net this species using seines and gillnets for fresh or frozen fillet sales and canning . The annual catch can reach 30 million fish in Bristol Bay , Alaska , which is the site of the world's largest sockeye harvest. Sockeye salmon have long been important in the diet and culture of the Coast Salish people of British Columbia. The largest spawning grounds in Asia are located on

1938-467: The headwaters of the sockeye salmon by preventing industrial development in roadless areas . Record numbers of a once-waning population of sockeye salmon have been returning to the Northwest's Columbia Basin (as of June 2012), with thousands more crossing the river's dams in a single day than the total numbers seen in some previous years. The conservation status of sockeye populations in Canada

1989-533: The intruding male leaving after one or two aggressive interactions. Spawning females direct their aggression primarily towards intruding females or other spawning females that are close by. However, they may also direct aggression towards intruding or subordinate males. Aggressive interactions between females only last one or two charges and/or chases. The intruder retreats and the spawning female settles back in her redd . These acts of aggression are important in terms of reproductive success, because they determine

2040-415: The juvenile stage. Sockeye salmon exhibit many different life histories with the majority being anadromous where the juvenile salmon migrate from freshwater lakes and streams to the ocean before returning as adults to their natal freshwater to spawn . Similar to most Pacific salmon , sockeye salmon are semelparous , meaning they die after spawning once. Some sockeye, called kokanee, do not migrate to

2091-404: The larger ones in a population. This shows natural selection against large bodies. Populations with higher levels of predation tend to evolve smaller body size. Without the threat of predation, salmon that breed early in the season live longer than those that breed late in the season. Other ecological factors like stranding effect select for smaller body size in sockeye salmon when present in

Wolford Mountain Reservoir - Misplaced Pages Continue

2142-586: The local extinction of bull kelp ( Durvillaea spp.) from Pile Bay . Lagoa Santa, a lake located in Lagoa Santa, Brazil , has lost almost 70% of the local fish species over the last 150 years. These include Acestrorhynchus lacustris , Astyanax fasciatus , and Characidium zebra . This could be caused by the introduction of non-native species, like Talapia rendalli , into the lagoon, changes in water level and organic pollution. Local extinctions can be reversed, in some cases artificially. Wolves are

2193-600: The low returns, the Government of Canada launched a formal inquiry into the decline, the Commission of Inquiry into the Decline of Sockeye Salmon in the Fraser River. The Commission has been tasked with investigating all the factors which may affect Fraser River sockeye salmon throughout their life cycle. According to the terms of reference, the subjects of investigation are "the impact of environmental changes along

2244-476: The ocean and live their entire lives in freshwater lakes. The majority of sockeye spawn in rivers near lakes and juveniles will spend one to two years in the lake before migrating to the ocean, although some populations will migrate to saltwater in their first year. Adult sockeye will spend two to three years in the ocean before returning to freshwater. Females will spawn in 3–5 redds over a period of several days. The eggs usually hatch within six to nine weeks and

2295-448: The possible impacts of diseases and parasites, hatchery diseases, contaminants, marine ecology, salmon farms, fisheries, predators, climate change and government management on the productivity of Fraser River sockeye runs. While the commission was holding public hearings, in the late summer of 2010, the largest run of sockeye since 1913 returned to the Fraser River system. Final counts show that approximately 30 million salmon returned to

2346-421: The quality of the nest site the female obtains and access to males. Competition for food or space while the salmon are in their lake residence period can exist. This happens when there is a more populous class of young sockeye or when there are multiple classes present. It can also happen when resources are in short supply. Interspecific competition can also occur and can lead to interactive segregation, which

2397-416: The sockeye salmon has to be accomplished with the energy stores brought to the spawning grounds. How the salmon use their energy during migration and spawning affects how successful they will be reproductively; energy used for migration cannot also be used for courtship . If they waste too much energy, they might not be able to spawn. Males must also make the decision whether to invest energy in fighting for

2448-711: The unexpectedly high sockeye run in 2010, on July 2, 2010, the United States Army Corps of Engineers reported over 300,000 sockeye had passed over Bonneville Dam on the Columbia River. Lower temperatures in 2008 North Pacific waters brought in fatter plankton, which, along with greater outflows of Columbia River water, fed the resurgent populations. Proposed legislative efforts, such as the Northern Rockies Ecosystem Protection Act , are attempting to protect

2499-685: The water column, timing and length of feeding, school formation, and choice of prey to minimize the likelihood of predation. This also ensures they still get at least the minimum amount of food necessary to survive. All of these behaviors contribute to the survivability, and therefore fitness of the salmon. Depending on location and threat of predation, the levels of aggressive feeding behavior can vary. Sockeye salmon, unlike other species of Pacific salmon, feed extensively on zooplankton during both freshwater and saltwater life stages. They also tend to feed on small aquatic organisms such as shrimp . Insects and occasionally snails are part of their diets at

2550-428: The west. The farthest inland sockeye salmon travel is to Redfish Lake , Idaho, over 1,400 km (900 mi) by river from the ocean and 2,000 m (6,500 ft) in elevation. In the United States, populations of sockeye salmon have been extirpated from Idaho and Oregon . Some sockeye salmon populations are completely landlocked. Sockeye that live and reproduce in lakes are commonly called kokanee , which

2601-441: Was estimated at a very low 1,370,000, 13% of the pre-season forecast of 10,488,000. That represented a decline from the recent (1993) historical cycle peak of 23,631,000 and the return abundance was the lowest in over 50 years. The reasons for this (former) decline remain speculative. According to a consortium of scientists assembled to review the problem, the decline highlights the uncertainty in forecasting salmon returns. After

SECTION 50

#1732788020481
#480519