WEIGHT-TO-WEIGHT CONVERSION FACTORS FOR MARINE BENTHIC MACROINVERTEBRATES

The measurement of macroinvertebrate biomass involves time-consuming p rocedures and the destruction of specimens. However, from simple wet w eight (WW) measurements, conversion factors provide rapid estimates of ash-free dry weight (AFDW) that facilitate large-scale comparisons of secondary production and energy flow. From a compilation of published and unpublished data, we have calculated general conversion factors f or 28 taxonomic groups of benthic marine macroinvertebrates, as well a s for several species of commercial importance. Despite methodological and regional differences among studies, narrow confidence limits surr ounded mean values for converting from WW to AFDW for polychaetes (16% ), prosobranch gastropods (7.5%), bivalves (5.8%), amphipods (16%), an d decapods (16.5%).