Dm. Mason et al., A SPATIALLY EXPLICIT BIOENERGETICS MEASURE OF HABITAT QUALITY FOR ADULT SALMONINES - COMPARISON BETWEEN LAKES MICHIGAN AND ONTARIO, Canadian journal of fisheries and aquatic sciences, 52(7), 1995, pp. 1572-1583
We used spatially explicit modeling to compare habitat quality for chi
nook salmon, Oncorhynchus tshawytscha, and lake trout, Salvelinus nama
ycush, in Lakes Michigan and Ontario. This grid-based approach predict
s a predator's physiological growth response, growth rate potential, f
rom measured physical and biological environmental conditions and is a
species-specific measure of habitat quality. Underwater acoustics was
used to map prey spatial distributions, abundances, and sizes. A fora
ging model defined predator consumption rates from prey data. A bioene
rgetics model calculated growth rate potential based on consumption ra
tes and prevailing thermal conditions. We compared habitat quality bet
ween lakes using both the mean growth rate potential and the volume (o
r proportion) of water capable of supporting positive growth rates. Me
an growth rate potential for both chinook salmon and lake trout was si
milar between the lakes despite known differences in the prey species
composition and abundance. However, Lake Michigan provided a greater v
olume of water capable of supporting growth for both chinook salmon (2
6%) and lake trout (21%) compared with that for Lake Ontario (19% for
both species). Our measure of habitat quality based on species-specifi
c physiological requirements should provide a tool to compare ecosyste
ms and quantify ecosystem change.