Annual variation in reproductive success and biomass of the major macrozoobenthic species living in a tidal flat area of the Wadden Sea
Beukema, J. (1982). Annual variation in reproductive success and biomass of the major macrozoobenthic species living in a tidal flat area of the Wadden Sea. Neth. J. Sea Res. 16: 37-45
In: Netherlands Journal of Sea Research. Netherlands Institute for Sea Research (NIOZ): Groningen; Den Burg. ISSN 0077-7579; e-ISSN 1873-1406, meer
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| Abstract |
Annual variation in recruitment and biomass was studied during 13 years for the 5 species contributing most to total zoobenthic biomass in a tidal flat area in the westernmost part of the Wadden Sea. In all of these species annual biomass values tended to be more stable than numbers of recruits. In Cerastoderma edule and Mytilus edulis recruitment variability was high, and was passed on almost completely to biomass, probably as a consequence of rapid juvenile growth and a high mortality, also in the adult stage, leaving few year-classes in the population. In Arenicola marina and in Mya arenaria biomass values varied much less than recruit numbers. Both species showed a low adult mortality rate with many year-classes present in the population, holding many old and heavy specimens that dominated biomass. Macoma balthica took an intermediate position in these respects. Recruitment was relatively stable in Arenicola and was probably controlled by the high numbers of adults. Recruitment variability was fairly low too in Macoma, but in this species juvenile mortality appeared to be directly related to their own density. Succesful and poor years for recruitment were roughly the same for the 4 bivalve species. Particularly heavy spatfall was found during the summer following the severe 1978-1979 winter. Such synchronized recruitment does not fully add to variability in annual biomass values as the time needed for the recruited cohorts to reach maximum biomass values differs greatly between most of the high-biomass species. |
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