warming Global impact on salmon
By Pailin Wongchaikunakorn
Salmon's life cycle
Source : http://www.fishex.com/seafood/salmon/salmon-life-cycles.html
Notes for slide 1 The salmon life cycle occurs in a chain of connected environments: stream, estuary, and ocean. Salmon are born in gravel nests at the bottom of stream and river beds. After they hatch out of the eggs, baby salmon live of the nutrient inside the yolk sac that still hangs below its body. After the yolk sac is completely absorbed, baby salmon or "fry" will group together to begin their journey downstream to the ocean. At this stage, salmon will grow to be about two to six inches long. Because of their small size, they continue to be very vulnerable to being devoured by any number of predators. They spend about one to three years at the mouth of streams and rivers until their bodies start to adapt to saltwater before migrating to the ocean. Adult salmon spend about one to five years in the ocean varying among the species. Only about 2 salmon out of 2,500 eggs survive and make their way to the ocean. During spawning season, adult salmon have to swim back from the ocean and upstream to the exact place where their life began. Female salmon will lay her eggs under the gravels, then the male salmon will fertilize the eggs. Both salmon will die within a couple of weeks after the eggs are fertilized.
The next slide will show how global warming affects salmon and their survival...
How does global warming affect salmon?
Intelorance of warmer water Increasing spread of bacteria and viruses from warmer region - scientists have been predicting will accompany global warming: Cold-temperature barriers are giving way, allowing parasites, bacteria and other disease-spreading organisms to move toward higher latitudes.
Habitat destruction
Salmon only live in cold water environment. They can survive in the habitat with the temperature range from 53F to 60F and the upper limit is 77F for short time periods. Above or below this range, temperature salmon will not be able to survive.
The University of Oregon's Institute for a Sustainable Environment shows the study that "a panel of 11 independent scientists told the Northwest Power Planning Council that temperatures in the Northwest have already gone up nearly 2 degrees Fahrenheit since 1900, which is 50 percent more than the global average. The increase is expected to continue at a rate of about 1 degree Fahrenheit each decade. This could result in a decrease salmon population." Salmon eggs hatch quicker in warmer water, which mean premature fry will be even more unlikely to survive from predators. Warmer oceans could reduce not only salmon population, but other smaller fish that salmon feed on. Source : http://www.redorbit.com/news/science/939249/global_warming_said_cu ts_salmon_habitat/index.html
Widespread of diseases
"white spot disease" is caused by a microscopic parasite called Ichthyophonus hoferi.
"Everything is getting warmer, and that's how climate change is going to redistribute all kinds of disease. Parasites have their optimum conditions -- upper and lower limits. We'll notice where they show up but not necessarily where they disappear.", Richard M. Kocan, University of Washington
Source :http://www.latimes.com/news/science/environment/la-naichfish15-2008jun15,0,6335392,full.story
Notes for slide 4
Salmon are more susceptible to disease in water that is warmer than 68 degrees Fahrenheit. The parasite causes small white spots on fish and a subtle, unpleasant odor similar to rotten fruit on a hot day. Richard Kocan, a fish disease specialist, said that the spread of this decease had to do with the warmer temperature. Because fish are cold blooded, therefore their body adjusts to whatever temperature the water is. With a higher temperature in the water, it accelerates the growth of bacteria and parasites living in the fish's body. Source : http://www.loe.org/shows/segments.htm?programID=08-P1300025&segmentID=4