Growth and survival of pacific coho salmon smolts exposed as juveniles to pesticides within urban streams in western Washington, USA.

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Growth and survival of pacific coho salmon smolts exposed as juveniles to pesticides within urban streams in western Washington, USA.

Environ Toxicol Chem. 2014 Jul;33(7):1596-606

Authors: King KA, Grue CE, Grassley JM, Fisk RJ, Conquest LL

Abstract
Pesticides are frequently detected in urban streams, with concentrations often exceeding those reported in surface waters within agricultural areas. The authors studied growth, survival, and return rates of coho salmon (Oncorhynchus kisutch) smolts exposed to a pesticide mixture (“cocktail”) representative of the pesticides most frequently reported within urban streams in western Washington State, USA, in fall through early spring. Exposure concentrations were selected to represent a reasonable worst-case scenario based on field monitoring data. Smolts were continuously exposed to pulses of the cocktail either from fertilization through swim-up (2007-2008) or from fertilization through smoltification (2007-2008 and 2008-2009), coded wire tagged, and released in 2008 and 2009. Pre-release endpoints (growth, survival, sex ratio, brain acetylcholinesterase activity, and gonado- and hepatosomatic indices) were not affected. However, the number of returning adults exposed to the cocktail to swim-up (0.90%, n = 42) was more than double that of unexposed controls (0.38%, n = 26) in 2008, whereas in 2009, fish exposed through smoltification returned in lower numbers (0.15%, n = 18) than controls (0.37%, n = 30). Variability in return rates among treatments between years was comparable to that observed in previous whole life cycle studies with Pacific salmon and other contaminants. Results suggest that exposure to pesticides in urban streams does not directly impair early life stages of coho salmon, and that additional studies incorporating releases of larger numbers of smolts across several years are necessary to adequately quantify effects on return rates.

PMID: 24687230 [PubMed – indexed for MEDLINE]

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Pesticides in urban streams and early life stages of Pacific coho salmon.

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Pesticides in urban streams and early life stages of Pacific coho salmon.

Environ Toxicol Chem. 2013 Apr;32(4):920-31

Authors: King KA, Grue CE, Grassley JM, Fisk RJ

Abstract
Pesticides are frequently detected in urban streams and are believed to be primarily the result of homeowner use. Although concentrations in most cases are low (<1 µg/L), there is concern that pesticide inputs threaten efforts to restore and enhance salmon habitat. The authors exposed early life stages of coho salmon (Oncorhynchus kisutch) to a pesticide mixture (“cocktail”) representative of those pesticides most frequently reported in urban streams in western Washington State, USA. Life stages were continuously exposed to pulses of the cocktail simulating those in urban streams in fall and winter when coho salmon eggs and sac fry are present. Nominal concentrations of eight herbicides, two insecticides, a fungicide, and a breakdown product were the maximum detected. Fertilization, hatching success, survival, deformities, and growth of fry were not significantly affected. A reduction in fertilization success (19-25%) was not reproducible even when gametes were exposed to 100 times the maximum concentrations detected. Based on the end points examined in the present study, the results suggest that direct exposure to the pesticides most frequently detected in urban streams in western Washington does not impair early life stages of coho salmon and is not a major factor governing the recovery of salmon populations. The extent to which pesticide exposure would affect smoltification, outmigration, and ocean survival needs to be determined.

PMID: 23297254 [PubMed – indexed for MEDLINE]

via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/pubmed/23297254?dopt=Abstract

Pesticides in urban streams and early life stages of pacific coho salmon.

Written by

Pesticides in urban streams and early life stages of pacific coho salmon.

Environ Toxicol Chem. 2013 Jan 7;

Authors: King KA, Grue CE, Grassley JM, Fisk RJ

Abstract
Pesticides are frequently detected in urban streams and are believed to be primarily the result of homeowner use. Although concentrations in most cases are low (<1 µg/L), there is concern that pesticide inputs threaten efforts to restore and enhance salmon habitat. The authors exposed early life stages of coho salmon (Oncorhynchus kisutch) to a pesticide mixture (“cocktail”) representative of those pesticides most frequently reported in urban streams in western Washington State, USA. Life stages were continuously exposed to pulses of the cocktail simulating those in urban streams in fall and winter when coho salmon eggs and sac fry are present. Nominal concentrations of eight herbicides, two insecticides, a fungicide, and a breakdown product were the maximum detected. Fertilization, hatching success, survival, deformities, and growth of fry were not significantly affected. A reduction in fertilization success (19-25%) was not reproducible even when gametes were exposed to 100 times the maximum concentrations detected. Based on the end points examined in the present study, the results suggest that direct exposure to the pesticides most frequently detected in urban streams in western Washington does not impair early life stages of coho salmon and is not a major factor governing the recovery of salmon populations. The extent to which pesticide exposure would affect smoltification, outmigration, and ocean survival needs to be determined. Environ. Toxicol. Chem. © 2013 SETAC.

PMID: 23297254 [PubMed – as supplied by publisher]

via pubmed: school of aquatic an… http://www.ncbi.nlm.nih.gov/PubMed/23297254?dopt=Abstract