Biotransport of Organic Pollutants to an Inland Alaska Lake by Migrating Sockeye Salmon (<i>Oncorhynchus nerka</i>)

Abstract

Persistent organic pollutants such as polychlorinated biphenyls (PCBs) and the pesticide DDT, known to harm wildlife, have been shown to reach pristine Subarctic and Arctic areas by global atmospheric transport. Another transport route for pollutant entry into these ecosystems is provided by migrating salmon. Pollutant transport was studied in a population of sockeye salmon (Oncorhynchus nerka) in the Copper River, Alaska during their 410 km spawning migration. Pollutants accumulated by the salmon during their ocean life stage were not eliminated during migration, but were transported to the spawning lakes and accumulated in the freshwater food web there. The influence of the biotransported pollutants was investigated by comparing pollutant levels and compositions in atmospheric deposition as well as in two different populations of arctic grayling (Thymallus arcticus). One grayling population was in the salmon spawning lake and the other in a nearby lake not hosting anadromous fish, but receiving pollutants only via atmospheric deposition. The grayling in the salmon spawning lake were found to have concentrations of organic pollutants more than two times higher than those of the grayling in the salmon-free lake, and the pollutant composition resembled that found in salmon. Thus, in the studied Alaska river system, biotransport was found to have a far greater influence than atmospheric input on the PCB and DDT levels in lake biota.

Energy content of Pacific salmon as prey of northern and southern resident killer whales

“…The lower lipid contents of the Chinook salmon from Puget Sound and Columbia River fall run fish sampled for this study (mostly lower river stocks) are likely due to the short distances they migrate upstream to spawn. Some of the variation in lipid content among Chinook salmon populations may also be associated with their advancing maturation state, as lipid content declines dramatically as fish move into freshwater and become sexually mature (Shearer et al 1994, Ewald et al 1998, Hendry & Berg 1999. For example, the difference in lipid content between immature (9.9%) and mature in-river-caught fish (6.1%) from Puget Sound suggests that the mature fish had started to metabolize their fat reserves for reproduction when sampled.…”

A Model Approach for Estimating Colony Size, Trends, and Habitat Associations of Burrow-Nesting Seabirds

“…• Reintroduction of pollutants leached, resuspended, or concentrated into biota from contaminated sediments • Biological transport of pollutants (e.g., Ewald et al 1998) Surface runoff or stormwater is the primary conveyance for many toxic contaminants of concern in Puget Sound, and the ultimate source for the bulk of these toxics has been attributed to everyday activities of people in developed residential areas, rather than industrial or municipal discharges (EnviroVision et al 2008). Pollution from runoff is the sum of contamination from many diffuse, "non-point," sources.…”

Effects of Climate Change on Arctic Marine Mammal Health

“…Biotransport.-Biotransport, transport by migratory animals rather than passive transport via air or water, is receiving increasing attention (Ewald et al 1998, Wania 1998. Deposition of contaminants by biotransport occurs through excretion (urine, feces, shedding/molting, etc.…”