Natural history of the species, including: habitat requirements, interactions wi
ID: 221041 • Letter: N
Question
Natural history of the species, including: habitat requirements, interactions with other species, behavior, reproduction, etc.) 7. Is this species population in decline? If so, what are the threats to this species? 8. Are there any conservation efforts being made for this species? 9. Was this species used by Native Americans? 10. Include a list of sources (bibliography) at the end of your report. Sources: Must include at least four different high-quality sources in your bibliography. Number each source in your bibliography. Whenever you use information from that source, include the source number after the information (footnote style see example below). You may use MLA orAPA (whichever type of citation you are most familiar with). When using websites, you must include the title of the website, not just the URL! Example: Question 4. Where is this species found (species range)? Herb Robert is native to the British Isles, Europe, Africa and parts of Asia (1) Sources (Bibliography) common British species. Unwin Hyman Ltd, London.Explanation / Answer
Introduction:
The chum salmon (Oncorhynchus keta) is a species of anadromous fish in the salmon family. It is a Pacific salmon, and may also be known as dog salmon or keta salmon, and is often marketed under the name silverbrite salmon. The name chum salmon comes from the Chinook Jargon term tzum, meaning "spotted" or "marked", while keta in the scientific name comes from the Evenki language of Eastern Siberia via Russian.
Weight:
8-15 pounds (3.6 to 6.8 kg) on average, but can weight up to 45 pounds (20 kg)
Length:
up to 3.6 feet (1.1 m)
Appearance:
Metallic greenish-blue in the ocean;
Spawning males have enormous canine-like fangs and striking body color marked by a reddish line and jagged black line.
Diet:
While in rivers, they eat insects and marine invertebrates while in rivers; as adults in the ocean, they eat "copepods", fishes, "mollusks", squid, and "tunicates".
Behavior:
Migrate from a marine environment into the freshwater streams and rivers of their birth; they spawn only once and then die;
they form schools, unlike most other species that rear in fresh water
Lifespan:
Chum live for an average of 3 to 4 years, and chum in Alaska mature at the age of 4 years.
Sizes:
Adult chum usually weigh from 4.4 to 10.0 kg (9.7 to 22.0 lb) with an average length of 60 cm (24 in). The record for chum is 19 kg (42 lb) and 112 cm (44 in) and was caught at Edie Pass in British Columbia.
Distribution:
Chum salmon are the most abundant wild salmon species in Washington State. The current distribution of chum salmon spans most of western Washington, including Puget Sound, the coast, and several lower Columbia River streams. The chum stocks of these three regions represent genetically distinct population groupings and are managed separately.
Along with sockeye and pink salmon, chum salmon have traditionally been considered a commercial fishing species. In the nineteen-nineties, chum salmon have been the most valuable of Washington produced salmon to state and tribal commercial fishers, in terms of total state-wide annual value. In recent years, however, there has been growing sport fishing interest in chum salmon, both in marine and freshwater fisheries. As sport fishing opportunities have been restricted for other species, the abundant chum salmon runs have been "discovered" by many salmon anglers, and new fishing locations and techniques are helping to make chum salmon an important sport fish.
Habitat factors:
Stream Habitat
Low stream flow can impede summer-run spawners, and high flows can disrupt the spawning of fall and winter chum.
Summer chum spawner distributions can be limited to sub-optimal stream reaches near tidal areas by the low flows that typically occur in late summer months. These low flows also force fish to spawn in the center of the stream channel, which can increase egg and alevin mortalities during subsequent winter floods. Fall and winter chum spawners are seldom limited by low flows, but frequently are affected by high flows, which disrupt upstream migration and can interfere with spawning activities.
Floods during the incubation period reduce the intergravel survival of eggs and alevins and can significantly affect future production.
All chum stocks can be negatively impacted by high flows (displacement of spawners and streambed scour) during the fall and winter incubation period. The erosion and downstream movement of spawning gravels is a major cause of egg and alevin losses, and severe flooding can cause mortalities as high as 90 percent.
Land use practices and natural events that introduce substantial amounts of silt to spawning streams affect chum intergravel survivals by reducing the permeability of the gravel, interfering with the delivery of water and oxygen to incubating eggs and alevins. Channelization and bank armoring reduces the amount, quality, and diversity of chum salmon spawning areas by narrowing and deepening the stream channel. Chum salmon rarely occur in streams above lakes or reservoirs because upstream migrating adults are often reluctant to pass through fishways and downstream migrant fry have difficulties successfully negotiating their way through still water impoundments.
Estuarine and Marine Habitat
Newly emerged chum fry migrate directly to salt water, and early marine survival is dependent on healthy estuaries providing good quality water, abundant food resources, and refuges from predators.
Juvenile chum salmon spend the first part of their marine lives in estuarine and near shore areas adjacent to their natal streams. These young chum salmon obtain their critical early growth by feeding in tidal sloughs and creeks and other intertidal areas. Most of the estuaries in Washington have been altered in some way by changes like channelization, dredging, diking, filling of wetlands and tidal areas, and degraded water quality. This extensive alteration and/or loss of estuarine habitat has been caused by factors such as urbanization, agriculture, forest land management, and industrial and water resource development. It has been estimated that 39% of the coastal wetlands and 70% of the Puget Sound emergent wetlands have been lost. These modifications tend to reduce the overall amount of habitat, and degrade the general productivity of estuaries (and lower food production), which limits overall utility of these areas for chum rearing. This can result in reduced growth rates, which can affect how fast the juvenile chum salmon grow to a size that reduces their vulnerability to predators.
Most chum salmon enter the open ocean during the summer and fall of their first year. They migrate northward to the Gulf of Alaska where they spend from 1 to 4 years feeding and growing. The North Pacific habitat is primarily influenced by natural climate processes that cause long term changes ocean temperatures and currents, which in turn can affect the production of food organisms utilized by chum and other salmon.
Biological Interactions
Predation
Predation effects on chum salmon are primarily caused by various fish species and birds during the juvenile life stage, and large fish species and marine mammals during the adult life history stage.
A variety of predator species feed on chum salmon throughout their life cycle. Juvenile chum are preyed upon by fish (including other salmonids) and birds in both the freshwater and marine environments. This type of predation does not normally threaten the success of chum populations unless they are subjected to unusual aggregations of predators. The release of hatchery fish of a variety of species is a common reason for large predator aggregations, and in some situations, this practice has been shown to negatively impact the survivals of chum salmon juveniles. Adult chum are subject to predation in marine areas by sharks, lampreys, and marine mammals, and in freshwater by bears, marine mammals, and large predatory birds.
Competition
Competition for food resources with other fish species in the near shore environment and open ocean can reduce chum survival and abundance.
Competition between chum salmon and other salmonids for spawning locations, and with a variety of species for food resources has been shown to impact chum survival rates. Temporal and spacial overlapping of spawning chum with other salmon spawners can result in reduced survivals caused by egg loss from redd superimposition. Competition for food with other fish species in the marine environment influences juvenile chum growth rates and survivals. In particular, the abundance of pink salmon sharing common marine areas with chum has been demonstrated to have a direct impact on chum survival and abundance.
Yes. The species is in decline. The influence of environmental change on fish population productivity is a central problem in fisheries science. For sockeye salmon, multi-stock analyses have indicated widespread declines in productivity over the past two decades for stocks ranging from Washington (WA) to Southeast Alaska [1]. These observed declines in productivity likely originate from a common oceanographic driver because sockeye salmon stocks throughout the southern part of their North American range show similar magnitude and directional changes in productivity [1]. Across broad spatial scales, productivity of sockeye, pink (O. gorbuscha), and chum salmon (O. keta) tend to be influenced similarly by changes in ocean conditions (e.g., sea surface temperature), suggesting that productivity of pink and chum salmon stocks in WA and British Columbia (BC) may have also declined over the past two decades [2]. However, productivity series between sockeye and chum salmon and sockeye and pink salmon tend to only be weakly to moderately correlated [3], possibly due to differences in life history strategies among species [4].
1. Peterman R, Dorner B. A widespread decrease in productivity of sockeye salmon (Oncorhynchus nerka) populations in western North America. Can J Fish Aquat Sci. 2012;69: 1255–1260. doi: http://doi.org/10.1139/f2012-063.
2. Mueter FJ, Peterman RM, Pyper BJ. Opposite effects of ocean temperature on survival rates of 120 stocks of Pacific salmon (Oncorhynchus spp.) in northern and southern areas. Can J Fish Aquat Sci. [Plus the corrigendum printed in Can. J. Fish. Aquat. Sci. 60: 757]; 2002;59: 456–463. doi: http://doi.org/10.1139/f02-020.
3. Pyper BJ, Mueter FJ, Peterman RM. Across-species comparisons of spatial scales of environmental effects on survival rates of Northeast Pacific salmon. Trans Am Fish Soc. 2005;134: 86–104. doi: http://doi.org/10.1577/T04-034.1.
4. Quinn TP. The behavior and ecology of Pacific salmon & trout. American Fisheries Society, Bethesda Maryland. University of Washington Press, Seattle; 2005.
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