Secondary production of Capitella sp. (Polychaeta: Capitellidae) inhabiting different organically enriched environments
D. Martín and A. Grémare

Three populations of Capitella sp. submitted to three different environmental conditions were monitored during one year in Alfacs Bay (Ebro Delta, NW Mediterranean) to estimate their respective contributions to the secondary production. Yearly secondary production of Capitella sp. at the three sites under study were 0.83 gDW. m-2. y-1 for the disturbed sand site, 3.74 gDW. m-2. y-1 for the typical silt site, and 36.9 gDW. m-2. y-1 for the disturbed silt site. The corresponding P/B ratios were of 4.09 y-1, 3.66 y-1 and 5.71 y-1, respectively. At the two silty sites, Capitella sp. presents: (1) a marked seasonal variability, and (2) high production rates and P/B ratios, which are two characteristics of opportunists. At the disturbed sand site its seasonal pattern is much more stable, and its production much lower (although P/B ratios are still high). The "within site" seasonal differences found between the three populations probably did not result from temporal changes in food quantity nor quality. Nevertheless, differences in protein concentrations may contribute to explain differences in maximal densities and biomasses observed among sites. Our results confirm that Capitella sp. shows a great plasticity relative to environment.

Contents of this volume Sci. Mar. 61(2) : 99-109 Back PDF
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