Talk:Oncorhynchus

Removal of section that editorializes and based on false premise

I've removed the section below from the article as it editorializes/generalizes about the effect of climate change on salmon. The article is about BOTH pacific salmon and trout, not just salmon. The opening sentences are completely unsupportable by sources. No Oncorhynchus species are assessed as endangered or imperiled in the Committee on the Status of Endangered Wildlife in Canada summary listings. Additionally, no Oncorhynchus species is listed as imperiled in British Columbia see Conservation status of British Columbia salmonids. Only two Oncorhynchus species, both trouts, are listed as of Special Concern in BC. All other Oncorhynchus as listed as apparently secure or demonstrably widespread, abundant, and secure. In the US only two salmon ESU are considered endangered, and one steelhead DPS is considered endangered, not the entire genus as this section implied --see Steelhead and salmon distinct population segments. The only source that is accessible online, is very speculative about the effects of Climate Change. The section as written does not characterize the content as speculation, it does so as fact. Such editorializing is best left to climate change articles. --Mike Cline (talk) 22:01, 7 December 2013 (UTC)

The following text was removed

Influence of climate change

According to the Committee on the Status of Endangered Wildlife in Canada, Pacific Salmon are collectively considered an endangered species; meaning the various species are facing “imminent extirpation or extinction.” Only 55.63% of total population levels of Pacific salmon in 2006 are remaining today and there has been no change in extinction risk since 2005. Only 3% of the total population in 2006 is still viable, or able to reproduce, in 2012 meaning a very likely risk of extinction in the near future. Because Pacific salmon (Oncorhynchus sp.) are important economic and cultural resources, their viability (or ability to survive) in response to future climatic change is of great concern. Global warming and climate change will soon cause warmer temperatures resulting in more precipitation falling as rain than as snow thus diminishing snowpacks and altering with the timing of stream flows. As more rain than snow occurs, there will be an increase in river flows, as there will be more water released from previously ice and/or snowpacks. This increase in temperature will also cause water temperature to rise overall. Not all of these anticipated effects are necessarily detrimental to the habitat of pacific salmon but they do have severe implications on the salmon population. However, as global temperature increases there will be a higher frequency of severe floods which will result in increased egg mortality since salmon eggs are laid in the gravel at the bottom of streams/lakes/oceans and disturbance of the stream bed will kill the salmon eggs. This flooding will also greatly disrupt the cycles for fall and winter spawning because Pacific salmon spend 2–3 years feeding in the North Pacific and then migrate to their home lake-stream system where they spawn and die. If the flooding changes the levels of the streams and lakes, then this will change migration patterns for salmon. Climate change will also cause winter snow to retreat sooner in the spring, possibly harming salmon whose life cycles and migration are timed with this snow retreat and linked to nearshore plankton blooms since now the retreat will be sooner but the plankton bloom will be around the same time. If this is the case, then salmon migrating back with the snow retreat will have limited food resources due to the divergence between the retreat and plankton bloom. Salmon return to their lake-stream nurseries in great numbers, in densities around 5,000 to 30,000 salmon per km2 and if snow retreats sooner in the spring the migration patterns of these densities of salmon could be changed and less salmon would be able to return to their nurseries to spawn. During the summer, summer flows will be lower and decrease the stream/lake/ocean system into smaller and less diverse areas. Computer modeling indicates, “with near 100% likelihood” that snowmelt timed earlier in the year will drop summer stream flows in basins with significant snowmelt by the year 2050. This will threaten the existence of cold-water fish, especially Pacific salmon. With increased global temperature, the issue of possibly decreased growth rates arises because warmer water temperature may affect the food supply required to support the increased metabolic demands of captive-raised salmon. A decrease in size at maturity has been shown in stocks over the past 42 years, coinciding with an increase in sea surface temperature in the ocean. If growth rates decrease, it could cause excess pre-spawning mortality because upstream migrations are arduous and smaller salmon have less energy stores to make the migration. Decreased growth rates due to higher global temperature means smaller salmon with less energy stores that have decreased ability to survive and less likely to reproduce therefore endangering the Pacific salmon population. Recommended water temperature for Pacific salmon are about 7-16 degrees Celsius and the upper lethal temperatures are between 25-26 degrees Celsius. With rising global temperatures due to climate change, the upper lethal temperature level for Pacific salmon are quickly approaching. If this level is reached and salmon go extinct, human and indigenous animal food resources will be lost and the economy built around salmon fishing destroyed.

--Mike Cline (talk) 21:51, 7 December 2013 (UTC)

Influences of overfishing

The following is regarding the section titled “Influence of overfishing”:

This information is a bit out dated and could use some updating. I have found an article on pacific salmon published in 2008 that goes into detail about the incline of pacific salmon since the end of the 1980s. It could be very beneficial to the article to add these recent findings and studies, so your information is up to date and correctly informs the reader.

In the same article, they not only go into detail about the incline in population, but they also talk about the ongoing consequences that the original dramatic decline in the population have had on the present population. These consequences include different reproductive strategies, age of maturation, and average size of the salmon. Adding some of these details to the article would provide more evidence for the claim that “reduction of productivity in pacific salmon is, in part, seeded in the overfishing and has caused a reduction in population sizes throughout pacific salmon species”.

Another beneficial addition to this article could be to look at the reduction in body size from a positive viewpoint. One in particular that comes to mind is the benefit a smaller salmon could have in a body of water effected by global warming. Smaller salmon like to be in warmer water, so with the water temperature increasing, smaller body size could be a positive change for the population.

Hard, J., Gross, M., Hilborn, R., Kope, R., Law, R., Reynolds, J., & Heino, M. (2008). Evolutionary consequences of fishing and their implications for salmon. Evolutionary Applications, 1(2). Retrieved September 30, 2014, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3352430/

--Krouskop.9 (talk) 21:52, 30 September 2014 (UTC)