Cumacean density, biomass and productivity in the sandy bottoms of the Blanes Bay (Western Mediterranean)

Abstract

During a study on seasonal dynamics and community structure of the sublittoral soft-bottom macroinfauna carried on from 1992 to 1997 in Blanes Bay, ten cumacean species were collected. Density and biomass of Bodotria pulchella, Iphinoe douniae, Pseudocuma longicorne and Pseudocuma simile (the most frequent species) were calculated based on fortnightly samples, from March to September 1992 . Bodotria pulchella showed the highest mean density (47.7 ind. m–2), while its mean biomass (AFDW) was 1.24 mg m–2. Iphinoe douniae showed 35.3 ind. m-2 on average, but its mean biomass was higher than in B. pulchella (2.01 mg m–2) due to its large size. The density and biomass trends varied independently among the four species. However, the corresponding trends for the whole population throughout the five years of study showed higher mean values of abundance and biomass during late spring / early summer. According to an empirical model, the secondary production for the four species ranged between 2.75 and 12.93 mg m–2 yr–1, while the corresponding P/B ratio ranged between 7.1 and 10.8. Although high, these values do not differ from those previously reported for other suprabenthic crustacean populations.