Scientists search for clues in salmon deaths

You might see it as a high stakes and incredibly complicated game of Clue. But instead of Colonel Mustard or Miss Scarlet with the lead pipe, scientists are looking at a dozen or so different culprits. They want to know why young salmon are dying in such high numbers when they venture into the marine waters of the Salish Sea. All researchers know for sure is that there has been what amounts to a murder—or many murders. For Puget Sound's Chinook, coho and steelhead, marine survival has declined by a factor of ten since the 1970s. 

New articles in Salish Sea Currents: following toxics through the food web

Watch for several new articles in Salish Sea Currents in the coming weeks. On Monday, senior writer Christopher Dunagan takes an in-depth look at new theories on the transport of PCBs through the Puget Sound foodweb. Conventional wisdom points to contaminants in the seafloor sediment, but new studies may show a radically different source. If the studies bear out, they will have big implications for Puget Sound's endangered Southern Resident Killer Whales, which are among the most contaminated marine mammals in the world. 

Comments: Formerly treated as conspecific with M. nigra (Linnaeus, 1758) [Black Scoter] of Eurasia, but separated on the basis of courtship calls (Sangster 2009) and color, form, and feathering of the bill in adult males and most adult females (Collinson et al. 2006) (AOU 2010).

Economic Uses

Comments: In recent decades, annual harvest in eastern North America averaged 22,500 (58% in eastern Canada) (Kehoe 1994).

Global Protection: Unknown whether any occurrences are appropriately protected and managed

Comments: No data available.

Biological Research Needs: More information is needed on basic biology (Kehoe 1994).

Conservation Actions

Conservation Actions

Conservation Actions Underway
No targeted conservation actions are known for this species, although it receives monitoring in parts of its range and occurs in some protected areas.

Conservation Actions Proposed
Improve monitoring surveys in order to obtain reliable baseline data and monitor future trends. Assess the significance of various threats. Tighten controls on marine pollution. Increase the area of suitable habitat that receives protection.

Degree of Threat: Low

Comments: Hydroelectric projects in Quebec and Labrador have had localized impacts on breeding habitat, but effects on the continental population probably have been small; urbanization and industrialization of many coastal bays and estuaries have degraded some winter habitat; chemical contamination and heavy metal accumulation of winter food supplies possibly may be affecting reproductive success of some populations (Kehoe 1994). Vulnerable to overharvest through hunting (Kehoe 1994).

Threats

Major Threats

Global Short Term Trend: Decline of 10-30%

Comments: For the period 1984-1994, estimated to be "declining in NW North America; possibly stable in Russia" (Goudie et al. 1994). However, available population data are generally inadequate for reliable determination of population trend (Kehoe 1994).

Global Long Term Trend: Relatively stable to decline of 50%

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