Biomass of deepwater demersal forage fishes in Lake Huron, 1994–2007: Implications for offshore predators

Abstract

We estimated the biomass of deepwater demersal forage fishes (those species common in the diets of lake trout and Chinook salmon) in Lake Huron during the period 1994–2007. The estimated total lake-wide biomass of deepwater demersal fishes in 2007 was reduced by 87 percent of that observed in 1994. Alewife biomass remained near the record low observed in 2004. Biomass of young-of-the-year rainbow smelt was at a record high in 2005, but little recruitment appears to have occurred in 2006 or 2007. Record-high estimates of young-of-the-year bloater biomass were observed in 2005 and 2007, and an increase in the biomass of adult bloater in 2007 suggests that some recruitment may be occurring. The biomass of other potential deepwater demersal forage fish species (sculpins, ninespine stickleback, trout-perch and round goby) has also declined since 1994 and remained low in 2007. The forage fish community in 2007 was dominated by small (< 120 mm) bloater and rainbow smelt. These results suggest that lake trout and Chinook salmon in Lake Huron may face nutritional stress in the immediate future.

Keywords:

• fish community
• alewife
• rainbow smelt
• bloater
• Great Lakes foodwebs

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Erratum

Acknowledgements

We thank the crew of the R/V Grayling and the scientists who contributed to development of the Lake Huron trawl data series. T. Desorcie, T. O'Brien, J. French, and J. Schaeffer assisted in data collection. D. Bunnell and two anonymous reviewers provided many suggestions that greatly improved the quality of this report. This is contribution number 1520 of the USGS Great Lakes Science Center.

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