Publication Abstract

Application of a biomass size spectrummodel to demersal fish data from the Scotian shelf

D.E. Duplisea

The distribution ofbiomass density over organism body size follows an orderly pattern in aquatic ecosystems.A recent theoretical model of such aquatic biomass size spectra predicts an overallprimary slope across all trophic groupings in an ecosystem, attributable to physiologicalcauses, and a set of secondary slopes of the biomass size spectrum, thought to be relatedto predator-prey interactions. Inter-annual variability in demersal fish biomass sizespectra from 1970-1991 on the Scotian Shelf was assessed using fits of secondary slopesderived from this model. The model was able to pick out 1976 as an anomalous year, whensquid abundance on the Scotian Shelf was very high. Similarly, it was shown that thefitted slope of the curve was stable after 1980, a fact that may reflect fisheriesmanagement practices implemented in the late 1970s. How the fitted slopes to dome shapedbiomass size spectra reflect the food resources available on the Scotian Shelf isdiscussed.

Reference:

D.E. Duplisea and S.R. Kerr, 1995. Application of a biomass size spectrum model todemersal fish data from the Scotian shelf. Journal of Theoretic Biology, 177: 263-269.