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What's depleting Salmon Populations? Horton, Jennifer. "What's depleting salmon populations?." 18 November 2008. HowStuffWorks.com. <http://adventure.howstuffworks.com/outdoor-­‐
activities/fishing/fish-­‐conservation/fish-­‐populations/salmon-­‐population.htm> 25 January 2010. The rivers and streams of the Pacific Northwest used to be so full of wild salmon that fishermen liked to say they could cross the waterways on the fish's backs. If salmon were the only means of crossing the rivers, those fishermen would be out of luck today. In California, Washington, Oregon and Idaho, salmon are extinct in nearly 40 percent of the rivers they were known to inhabit -­‐-­‐ at least 106 major stocks gone forever [source: Northwest Power & Conservation Bill Schaefer/Stringer/Getty Images Sights like this one are becoming rare as fewer salmon make it back to their birthing Council]. grounds to spawn. Around the world, the story is much fell 80 percent from 1970 to 2000. In the United the same: Global Atlantic salmon catches Kingdom, one-­‐third of the salmon population is endangered according to the World Wildlife Federation (WWF), and in California and Oregon, the Pacific Fishery Management Council recently announced the strictest salmon fishing quotas in the region's history due to the animal's rapid decline [source: Young, Environment News Service] The downward spiral of the salmon population is troubling for several reasons. This fish is far more than just a tasty source of omega-­‐3s. Salmon are what's known as a keystone species -­‐
-­‐ like the engine in your car, their physical presence compared to the whole is rather small, but their importance to its functioning is vital. Not only are the fish a main source of sustenance for a variety of predators (more than 137 species), but their decomposing carcasses are a significant source of nutrients and fertilizer for trees [source: Hunt]. When the salmon go, the surrounding ecosystem likely won't be far behind. Unfortunately, there isn't an easy solution for reversing the decline in salmon populations -­‐-­‐ everything from overfishing to El Nino and climate change have been linked to salmon depletion. The fish's complicated life cycle -­‐-­‐ salmon begin life in a stream, migrate to sea for their adult life and finally return to their birthplace in order to reproduce -­‐-­‐ makes it even harder to pinpoint the primary factors leading to each population's fall. The Four H’s But researchers do know enough about the leading causes of salmon decline to label them with a nifty slogan. Keep reading to find out what the four Hs -­‐-­‐ harvest, hatchery, habitat and hydropower -­‐-­‐ are all about. Harvest and Hatchery What's depleting Salmon Populations? Horton, Jennifer. "What's depleting salmon populations?." 18 November 2008. HowStuffWorks.com. <http://adventure.howstuffworks.com/outdoor-­‐
activities/fishing/fish-­‐conservation/fish-­‐populations/salmon-­‐population.htm> 25 January 2010. While a variety of factors impacts salmon populations, four tend to stand out. Although there are only six species of salmon -­‐ five Pacific and one Atlantic -­‐ each individual stock, or population, is genetically unique and faces challenges specific to its region, making it difficult to label any one of the four Hs more important. Two of the H factors are somewhat interrelated. The first one, harvests, refers to the commercial, recreational and tribal fishing of salmon -­‐-­‐ either out at sea or as they migrate back upstream. Until Robb Kendrick/Aurora/Getty Images recently, many governments have failed to put Catches like this one may not be possible in the future if appropriate limits on the number of salmon that overfishing continues. can be reasonably caught each year. For example, in Canada, when around 8 million salmon returned from the ocean to spawn in 1917, the government still allowed a catch of more than 7.3 million fish [source: Hume]. Overfishing has led to record low levels of the salmon almost everywhere they're caught. An exception is in Alaska, where well-­‐developed management plans give sustainability a high priority. The severe salmon depletions prompted by overfishing have led to a subsequent increase in fish hatcheries, the next big H, to replenish the stocks. Initially created to enhance salmon numbers, these fish nurseries artificially raise young salmon until they're self-­‐supporting and then release them into the ocean. Similar facilities now exist solely for food production and are referred to as fish farms. Farmed vs. Wild You might think eating farmed salmon helps the wild ones, but wild-­‐caught Alaskan salmon or Marine Certified Species (MCS) salmon is actually a better bet. By looking for the MCS label, you're ensuring the fish you eat comes from a sustainable source. Eating farmed fish simply encourages the harmful practices many fish farms engage in, which endanger the wild populations in the first place. If you do choose farmed fish, look for those that are farmed in open sea conditions and avoid using wild-­‐caught fish as feed . Ironically, the hatcheries and farms that popped up to alleviate pressure on wild salmon populations are now endangering them. Research shows that situating fish farms near wild salmon populations can cause declines of more than 50 percent in the wild fish [source: Owen]. Both hatcheries and farms may introduce weaker genes into the wild population's gene pool through interbreeding, thus lowering salmons' chances for survival. In addition, the artificial structures are more conducive to parasites and disease, which then infect wild populations. Competition is also a factor. Both harvest and hatchery problems can easily be fixed. With proper management and controls, populations can and do improve. Better quality fish cages, for instance, can prevent What's depleting Salmon Populations? Horton, Jennifer. "What's depleting salmon populations?." 18 November 2008. HowStuffWorks.com. <http://adventure.howstuffworks.com/outdoor-­‐
activities/fishing/fish-­‐conservation/fish-­‐populations/salmon-­‐population.htm> 25 January 2010. physical contact between the fish, and stricter controls on harvest quotas can help deter overfishing. The next two Hs, also man-­‐made, have to do with where salmon live. Habitat and Hydropower The health of salmon populations depends a lot on the health of their living environment. The fact that salmon live in a variety of habitats throughout their lives makes them especially vulnerable to the next H -­‐ habitat degradation. Even small disturbances can make a big difference, since spawning is highly sensitive to things like increased sedimentation. Logging, agricultural practices, trash dumping and oil spills all contribute to poor water quality. Joel Sartore/National Geographic/Getty Images Another factor that can disrupt habitat is the final Without modifications, hydropower dams block salmon H, hydropower dams. The Clearwater coho from accessing vital habitats. salmon, once abundant in the Snake River Basin of Oregon, Washington and Idaho, became extinct in the early 1960s largely due to the construction of a dam that blocked the fish's passage to and from its birthing grounds [source: Northwest Power & Conservation Council]. Besides potentially blocking access to salmons' habitats, dams may cause changes to water flows and temperatures that can devastate local populations. Dams aren't necessarily a death knell for The Fifth H salmon, however. Researchers tracking th
Professor David Montgomery claims the 5 H salmon on the dam-­‐laden Columbia River should be History – that of salmon-­‐human concluded it wasn't the dams impeding their interactions, especially in Britain & in the NE US. survival but challenges they face at sea including predation, ocean warming and The Sixth H! -­‐ Heat alterations to their prey distribution [source: Global Warming Strikes Again Owen]. The study showed that with proper Increasing evidence shows that climate change modifications to assist the salmon in their may affect salmon migration patterns. Warmer migration, dams and salmon can coexist. ocean temperatures cause the fish to migrate further north, creating a longer distance for them to travel than in cooler years. In addition to a delayed return to their spawning grounds, many of the fish experience reduced body size since more energy is required to cover the longer distance. Higher water temperatures may also cause increased stress and pre-­‐spawning mortality for some species like sockeye salmon [source: Levy]. The four Hs -­‐-­‐ harvests, hatcheries, habitat and hydropower -­‐-­‐ aren't problematic in and of themselves. It's only when salmon are mismanaged that things start to go downhill. While some populations have dropped so low they will take years to restore, if at all, others can be saved from following the path of the Clearwater coho. Please answer all questions in complete, quality and correct sentences on a separate sheet of paper. (schmied©2010) What's depleting Salmon Populations? Horton, Jennifer. "What's depleting salmon populations?." 18 November 2008. HowStuffWorks.com. <http://adventure.howstuffworks.com/outdoor-­‐
activities/fishing/fish-­‐conservation/fish-­‐populations/salmon-­‐population.htm> 25 January 2010. Purpose: I understand the life cycle of the Pacific salmon & know how humans can impact the health of salmon populations. 1. Wild Pacific Salmon in the lower 48 states are in real trouble! Tell the percentage of rivers that salmon are now extinct in AND tell how many major salmon stocks are gone forever. 2. Globally Atlantic salmon, which can migrate more than once, are also in serious trouble. Explain how much the Atlantic Salmon catches went fell between 1970 and 2000 AND tell what the World Wildlife Federation says about the United Kingdom’s Atlantic Salmon population. 3. The article says that Salmon are a keystone species. Explain what is meant by Keystone species. 4. Explain why it is difficult for scientists to pinpoint the causes of the salmon’s decline. 5. Tell what the four H’s of salmon decline are. 6. Describe why the salmon harvest is causing the salmon decline. Use data in your explanation. 7. Tell 2 reasons why salmon hatcheries and fish farms are causing the wild salmon stocks to decline. What's depleting Salmon Populations? Horton, Jennifer. "What's depleting salmon populations?." 18 November 2008. HowStuffWorks.com. <http://adventure.howstuffworks.com/outdoor-­‐
activities/fishing/fish-­‐conservation/fish-­‐populations/salmon-­‐population.htm> 25 January 2010. 8. Tell at least 4 ways a salmon’s habitat is being degraded. 9. Describe when AND why the Clearwater Coho went extinct? 10. Tell two other reasons dams may devastate salmon populations. 11. There have been a lot of research reports done pointing at least one of the 4 H’s as the cause of the salmon’s demise. However one recent research report identified 2 other reasons not connected to the 4H’s for the Columbia River salmon’s decline. Tell both. 12. Challenge / EC: People are starting to call Heat the 6th H. Please explain 3 reasons why rising ocean temperatures contribute to the salmon’s decline. 13. Challenge / EC Explain why David Montgomery, in his book King of Fish: The Thousand year Run of Salmon, claims that the historical interactions between humans and salmon should be considered the 5th H. Think about this and tell me why you think this is so.