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Gastric evacuation rate, index of fullness, and daily ration of Lake Michigan slimy sculpin (Cottus cognatus) and deepwater sculpin (Myoxocephalus thompsonii)

Journal of Great Lakes Research

By:
,
DOI: 10.1016/j.jglr.2013.03.007

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Abstract

Accurate estimates of fish consumption are required to understand trophic interactions and facilitate ecosystem-based fishery management. Despite their importance within the food-web, no method currently exists to estimate daily consumption for Great Lakes slimy (Cottus cognatus) and deepwater sculpin (Myoxocephalus thompsonii). We conducted experiments to estimate gastric evacuation (GEVAC) and collected field data from Lake Michigan to estimate index of fullness [(g prey/g fish weight)100%) to determine daily ration for water temperatures ranging 2–5 °C, coinciding with the winter and early spring season. Exponential GEVAC rates equaled 0.0115/h for slimy sculpin and 0.0147/h for deepwater sculpin, and did not vary between 2.7 °C and 5.1 °C for either species or between prey types (Mysis relicta and fish eggs) for slimy sculpin. Index of fullness varied with fish size, and averaged 1.93% and 1.85% for slimy and deepwater sculpins, respectively. Maximum index of fullness was generally higher (except for the smallest sizes) for both species in 2009–2010 than in 1976 despite reductions in a primary prey, Diporeia spp. Predictive daily ration equations were derived as a function of fish dry weight. Estimates of daily consumption ranged from 0.2 to 0.8% of their body weight, which was within the low range of estimates from other species at comparably low water temperatures. These results provide a tool to estimate the consumptive demand of sculpins which will improve our understanding of benthic offshore food webs and aid in management and restoration of these native species in the Great Lakes.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Gastric evacuation rate, index of fullness, and daily ration of Lake Michigan slimy sculpin (Cottus cognatus) and deepwater sculpin (Myoxocephalus thompsonii)
Series title:
Journal of Great Lakes Research
DOI:
10.1016/j.jglr.2013.03.007
Volume
39
Issue:
2
Year Published:
2013
Language:
English
Publisher:
Elsevier
Contributing office(s):
Great Lakes Science Center
Description:
p. 9
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
327
Last page:
335
Other Geospatial:
Lake Michigan
Additional Online Files(Y/N):
N