Wg. Sprules et Jd. Stockwell, SIZE-BASED BIOMASS AND PRODUCTION MODELS IN THE ST-LAWRENCE GREAT-LAKES, ICES journal of marine science, 52(3-4), 1995, pp. 705-710
Recent theoretical advances indicate that the size distribution of nor
malized biomass in aquatic food webs can be modelled by a primary line
ar scaling and a series of repeated quadratic curves corresponding to
component trophic groups. These secondary parabolas all have the same
curvature and are shifted fixed distances from one another. Hence the
parabolic normalized biomass distribution for any trophic group can be
predicted from a given trophic group. We use mean annual zooplankton
data from Lakes Ontario and Erie to predict fish biomass spectra, and
then convert fish biomass to annual production using established body
size-dependent production relationships. For Lake Ontario we estimate
fish production to be 19.2 +/- 5.0 fresh g m(-2) yr(-1), which compare
s favourably with independent growth model estimates. Lake Erie total
fish production is estimated to be 22.1 +/- 5.2 g m(-2) yr(-1), of whi
ch combined annual sports and commercial harvest constitute 4-6%. Thes
e size-based production techniques are less costly and time-consuming
than traditional species-based approaches. (C) 1995 International Coun
cil for the Exploration of the Sea