Deepwater Demersal Fish Community Collapse in Lake Huron

Abstract

Long‐term fish community surveys were carried out in the Michigan waters of Lake Huron using bottom trawls from 1976 to 2006. Trends in abundance indices for common species (those caught in 10% or more of trawl tows) were estimated for two periods: Early (1976‐1991) and late (1994‐2006). All common species significantly decreased in abundance during the late period with the exception of the johnny darter Etheostoma nigrum and spottail shiner Notropis hudsonius, which showed no significant trends, and the round goby Neogobius melanostomus, which increased in abundance. Percentage decreases in abundance indices between 1994‐1995 and 2005‐2006 ranged from 66.4% to 99.9%, and seven species decreased in abundance by more than 90%. The mean biomass of all common species in 2006 was the lowest observed in the time series and was less than 5% of that observed in the mid‐1990s. The mean number of common species captured per trawl has also decreased since the mid‐1990s. Several factors, including recent invasion of the lake by multiple exotic species, may have contributed to these declines, but insufficient published data are currently available to determine which factors are most important. Our observations suggest that significant changes have occurred in the ecology of Lake Huron since the mid‐1990s. The extent of these changes indicates that the deepwater demersal fish community in Lake Huron is undergoing collapse.

Seasonal zooplankton dynamics in Lake Michigan: Disentangling impacts of resource limitation, ecosystem engineering, and predation during a critical ecosystem transition

“…Similar patterns appeared somewhat earlier in Lake Huron, so it is likely that many of the same forces are playing out in both systems (Barbiero et al, 2009a;Riley et al, 2008).…”

Misapplied survey data and model uncertainty result in incorrect conclusions about the role of predation on alewife population dynamics in Lake Huron: a comment on

“…The US Geological Survey (USGS) has conducted bottom trawl surveys of prey fish in Lake Huron since the 1970s (Riley et al 2008, and USGS reports and publications clearly indicate that the indices of fish abundance derived from these surveys are not absolute abundance or biomass estimates and should not be interpreted as such (e.g., Riley et al 2008Riley et al , 2014. He et al (2015), however, contend that "the swept-area indices of biomass for age-1 and older alewives are close to the actual biomass in the main basin" (p. 17) and that the catchability of yearling and older (YAO) alewives in the Lake Huron bottom trawl survey is "near to 1.0" (p. 17).…”

“…Drastic recent and ongoing changes to fish populations and food webs in the Great Lakes have been well-described (Riley et al 2008;Barbiero et al 2009;Nalepa et al 2009;Fahnenstiel et al 2010;Evans et al 2011;Gobin et al 2015), and uncertainty regarding their potential effects on fisheries has caused concern among scientists and fishery managers (e.g., Dettmers et al 2012). In particular, the relative importance of "bottom-up" (e.g., lower trophic level changes) versus "top-down" (e.g., predation) factors to fish community changes in the Great Lakes have been widely debated (e.g., Barbiero et al 2011;Eshenroder and Lantry 2012;Bunnell et al 2014).…”

“…In particular, the relative importance of "bottom-up" (e.g., lower trophic level changes) versus "top-down" (e.g., predation) factors to fish community changes in the Great Lakes have been widely debated (e.g., Barbiero et al 2011;Eshenroder and Lantry 2012;Bunnell et al 2014). In Lake Huron, recent ecosystem changes have been particularly profound, and populations of alewife (Alosa pseudoharengus), an offshore pelagic prey fish, collapsed in 2003 and have yet to recover (Riley et al 2008. He et al (2015) recently used a series of linked ecological models to assess the role of predation in the dynamics of the offshore prey fish community in Lake Huron.…”

Site fidelity of escaped rainbow trout to an experimental freshwater aquaculture facility and habitat overlap with native fish fauna

“…This is the case for Lake Huron, which is undergoing significant changes to food-web structure and fish community composition (e.g. Riley et al 2008, Dunlop et al 2010). Furthermore, telemetry, which has proven a useful tool to monitor the movements and habitat use of aquatic animals, has limitations in the case of farmed salmonids that disperse long distances from cage sites.…”