. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. // 46 AGEiyr) 5 10 15 SOMATIC WEIGHT (g) 025 050 075 10 LIFESPAN Figure 8. Reproductive effort. 100 X Pr/(PB + P,). as a function of age. somatic weight and lifespan in the scallop Placn/'cilcn niuxcl/unicm •- - • Sunnyside (10 m); O---O Sunnyside (31 ml: •---• St. An- drews! 10 m); D---DSI. Andrews (31 m); A---A New Jersey. production in P. magellanicus is probably controlled pri- marih h\ local environmental factors, especially food supply, which determines the nutrient reserve and hence the capability to initiate gamete d
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. // 46 AGEiyr) 5 10 15 SOMATIC WEIGHT (g) 025 050 075 10 LIFESPAN Figure 8. Reproductive effort. 100 X Pr/(PB + P,). as a function of age. somatic weight and lifespan in the scallop Placn/'cilcn niuxcl/unicm •- - • Sunnyside (10 m); O---O Sunnyside (31 ml: •---• St. An- drews! 10 m); D---DSI. Andrews (31 m); A---A New Jersey. production in P. magellanicus is probably controlled pri- marih h\ local environmental factors, especially food supply, which determines the nutrient reserve and hence the capability to initiate gamete development (Newell cl ul. 1982). Comparisons of shell growth rates from our own study and others show that differences in shell height at any given age in scallops from Newfoundland. New Bruns- wick, and Georges Bank are small (Fig. 9). and that there is as much variation between depths at several sites in eastern Newfoundland (MacDonald and Thompson. 1985a) as there is between populations at different lati- tudes. We have some evidence for an increase in asymp- totic height in PlacopctU'ii magellanicus at higher lati- tudes, which is consistent with studies on some bivalve species, hut not others (see Introduction). However, there is a clear differentiation in longevity, which is greater in northern than in southern populations. Care must be taken when comparing shell growth rates from ditlerent populations, especially when the von Ber- talanlh function is used. It is not appropriate to base comparisons on the parameter K when the asymptotic heights or lengths differ considerably between popula- tions because K is inversely related to H / (Ralph and Maxwell. 1977; Haukioja and Makala. 1979). Further- more. K is a growth coefficient and should not he re- garded as a growth rate />X^}. Main ot the literature values for von Bertalanlly parameters are of limited \alue for comparative purposes, since confidence limits are often not provided. but several statistical packa
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
