Spatio-temporal variation in Coregonid larvae growth and density in Thunder Bay Lake Huron in 2017

Session: 29. - Preliminary Results from the 2017 CSMI Intensive Field Year on Lake Huron

David Wells, CIGLR, [email protected]
Ed Rutherford, NOAA Great Lakes Environmental Research Laboratory, [email protected]
Joann Cavaletto, NOAA GLERL, [email protected]
Henry Vanderploeg, NOAA GLERL, [email protected]
Paul Glyshaw, University of Michigan CIGLR, [email protected]
Doran Mason, NOAA Great Lakes Environmental Research Lab, [email protected]
Steve Pothoven, NOAA-GLERL, [email protected]
Angelika Kurthen, CIGLR, [email protected]
Stephen Lenart, US Fish and Wildlife Service, [email protected]
Chris Olds, US Fish and Wildlife Service, [email protected]

Abstract

Restoration and conservation of sustainable native coregonid populations is a top priority of fisheries managers throughout the Great Lakes but may be affected by environmental conditions and prey densities that vary among nursery areas. In Lake Huron, the spring phytoplankton bloom has largely disappeared and the composition, distributions and densities of the zooplankton community have markedly changed. During CSMI 2017, we sampled environmental conditions, fish larvae and zooplankton along a nearshore (10m) to offshore (82m) transect in Thunder Bay. We sampled fish larvae using a neuston and Multiple Opening/Closing Net and Environmental Sensing System (MOCNESS), zooplankton using lift nets and a laser optical plankton counter, and chlorophyll and temperature using CTD and fluoroprobe. In May and June, results indicate that most coregonid larvae were collected in nearshore areas with low chlorophyll a and zooplankton biomass. Daily growth rate of coregonid larvae was 0.35 mm/d. Densities of larvae sampled in 2015-2017 by USFWS were 3-fold higher in 2015 and 2017 when water temperatures were higher compared to lower densities and temperature in 2016. Densities of larvae were correlated with juvenile catches in July. Identification of environmental conditions that affect larval growth and survival may help identify recruitment bottlenecks to coregonid restoration.

1. Keyword
Lake Huron

2. Keyword
fish

3. Keyword
zooplankton

4. Additional Keyword
Larval Fish

5. Additional Keyword
Food Web Dynamics