Estimating secondary production in bathyal suprabenthic peracarid crustaceans from the Catalan Sea slope (western Mediterranean; 391-1255 m)

A first estimate of secondary production in populations of deep-water suprabenthic peracarids of the Catalan Sea slope (northwestern Mediterranean) was attempted. Estimates are based both on the size-frequency Hynes-Hamilton method and on two empiric models. Our data set was based on four oceanographic cruises carried out in 1991 and 1992 between 391 and 1255 m depth, covering the four annual seasons (April 1991, December 1991, March 1992, and July 1992). Production oscillated, depending of each species, between 0.129 mg DW/m(2)/year for the Cumacea Leucon longirostris and 9.002 mg DW/m2/year for the mysid Boreomysis arctica. PIE ratios ranged between 1.56 for L. longirostris and 12.64 for the Amphipoda Rhachotropis glabra. The extreme results cited were always obtained with the Hynes-Hamilton method. Comparing the two empiric models used, Brey's (1990) equation values were always lower than the results obtained with the Morin and Bourassa (1992) model, both for production and PIE ratios. Our production values for deep-sea peracarids were always lower (4-5 orders of magnitude lower in the case of Amphipoda) than available data for marine littoral and shallow-water peracarids. However, PIE ratios obtained from our suprabenthic deep-water peracarids were within the same range as that cited for coastal and neritic species. Also, and summarising the available data, suprabenthos crustaceans showed higher PIE ratios than infauna, whereas PIE for our suprabenthic species were within the range cited for mesopelagic euphausiids. (C) 1999 Elsevier Science B.V. All rights reserved.