BIOLOGY OF THE MYSID MESOPODOPSIS-SLABBERI (VAN-BENEDEN, 1861) (CRUSTACEA, MYSIDACEA) IN A COASTAL LAGOON OF THE EBRO DELTA (NW MEDITERRANEAN)

Aspects of the population and reproductive biology of the mysid Mesopo dopsis slabberi were studied in the western Mediterranean (Encanyissad a coastal lagoon, Ebre delta, Spain). Misids were sampling at monthly intervals from August 1993 to June 1995. In December 1994 and February 1995 any individuals were found. The relationship between carapace le ngth (Lc) and total length (Lt) was isometric: logLt=1.0612logLc+0.941 1 (n=178, r=0.9411). The size of mature males and females was at a max imum in the winter, and a minimum in the summer. The longevity of indi viduals changed throughout the year; those with the longest life expec tancy were members of the overwintering generation. Brooding females w ere recorded throughout the year, except in December 1993 and April 19 94; they were most numerous in spring and autumn. The number of embryo s or larvae (N) carried by females was related to the size of the fema les (range: 1-22, mean value: 4.8): logN=1.8705logLc-0.0985 (n=361, r= 0.4097, P<0.01). The size of the eggs (maximum diameter, Le) was relat ed to the size of the females (range: 0.35-0.6 mm in total length): lo gLc=0.3404logLc-0.4820 (n=277, r=0.5420, P<0.01).