BIOMASS VARIATIONS OF ESTUARINE MACROBENTHOS PRESERVED IN ETHANOL ANDFORMALIN

Three preservative treatments were compared for their effects on bioma ss of macrobenthic species collected at Biloxi Bay, Mississippi. We te sted the hypothesis that biomass did not differ among treatments once specimens. were fixed in 10% formalin. Two commonly used analyses, wet -weight biomass and dry-weight biomass, were tested, Wet-weight variat ions among treatments were compared over time. Dry-weight calculations were not possible on individuals over time because specimens could be dried only once, so ratios of dry weight to wet weight were calculate d on specimens at the conclusion of each treatment, Specimens were fix ed in 10% formalin for 2 wk, then transferred to either 1% formalin or 70% ethanol, or left in 10% formalin. Wet-weight biomass of the three treatments was determined weekly four times, and then specimens were dried for 72 h at 60 degrees C for dry-weight determinations. Biomass of most taxa lived in formalin and preserved in ethanol or formalin di d not vary significantly in wet weight over time. Minor variations amo ng the treatments occurred in dry-weight biomass. Whereas previous inv estigators found that ethanol affected biomass when specimens were not formalin-fixed, our results supported the premise that three commonly used preservative treatments did not differ in their effects on bioma ss of estuarine macrobenthos. Therefore, ive propose that estuarine ma crobenthos be fixed in formalin, then transferred to ethanol for bioma ss procedures in order to avoid exposure of laboratory personnel to ca rcinogenic formalin.