Document Detail

Biotic interactions in temporal trends (1992-2010) of organochlorine contaminants in the aquatic food web of Lake Laberge, Yukon Territory.
MedLine Citation:
PMID:  23178892     Owner:  NLM     Status:  Publisher    
Declines in 6 organochlorine (OC) contaminant groups; chlordane (CHL), DDT, HCH, toxaphene (CHB), PCB and chlorinated benzenes (CBz) were measured in biota of a sub-Arctic lake (Lake Laberge, YT) following the closure of a commercial fishery in 1991. This study examined morphological (length, weight, age), biochemical (lipid content, δ(13)C, δ(15)N), population and OC data for 9 fishes and zooplankton between 1993 and 2003 (2010 for lake trout) to investigate causes for the OC declines. Growth dilution was a major factor influencing the decrease of OCs in lake trout, round whitefish and possibly zooplankton most notably in the early 2000s. A decline in lipids of most fish species also contributed to OC declines, although no such change was evident for zooplankton. It is suspected that increases in fish populations or climate variations over the 1990s, may have contributed towards a shift in plankton community composition. From 1991 to 1999, CPUE increased for 7 of the fish species and declined for 2 others. Concurrently, the zooplankton community shifted from an abundance of C. scutifer in 1993 to dominance by D. pribilofensis in 2001. Nitrogen and carbon stable isotope data suggested that food web interactions for most fish species have not changed over time. Although concentrations of OCs have declined in many fishes, the "rate" of OC transfer (using slopes of log OC vs. nitrogen isotope ratios) through the food web was greater in 2001 than in 1993. Overall, the declines in OC concentrations in the fish from Lake Laberge occurred concurrently with changes in their growth, lipid, and abundance, suggesting that ecosystem responses to the closure of the fishery were in part responsible for the lower contaminants in these fishes. As a result of this study, the Yukon government rescinded the health advisory for limiting the consumption of fish from Lake Laberge.
M J Ryan; G A Stern; K A Kidd; M V Croft; S Gewurtz; M Diamond; L Kinnear; P Roach
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-11-22
Journal Detail:
Title:  The Science of the total environment     Volume:  443C     ISSN:  1879-1026     ISO Abbreviation:  Sci. Total Environ.     Publication Date:  2012 Nov 
Date Detail:
Created Date:  2012-11-26     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0330500     Medline TA:  Sci Total Environ     Country:  -    
Other Details:
Languages:  ENG     Pagination:  80-92     Citation Subset:  -    
Copyright Information:
Copyright © 2012 Elsevier B.V. All rights reserved.
Fisheries & Oceans Canada, Freshwater Institute, 501 University Crescent, Winnipeg, Manitoba, Canada R3T 2N6; University of Manitoba, Dept. of Soil Science, Winnipeg, Manitoba, Canada R3T 2N2.
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