The biology and population dynamics of Talitrus saltator (Montagu, 1808), a talitrid amphipod of the supralittoral zones of sandy beaches, was studied from December 2001 to December 2003 at Korba beach, Tunisia. Ovigerous females and the emergence of new cohorts were observed during the warmer months, with recruitment taking place from February-March to November. The population thus showed a seasonal pattern of reproduction, with stronger breeding during summer. The sex ratio was slightly in favour of females. Mean brood size was 11 and fecundity appeared to be positively correlated with female size. Life span was estimated at 6 to 9 months depending on the time of birth, with cohorts born at the beginning of the reproductive period tending to have shorter lives than those born later in the season. The present two-year study was consistent with previous preliminary results obtained at Zouara (Tunisia) , confirming Talitrus saltator as a semiannual species, with iteroparous females and a bivoltine life cycle. Growth production (P) was estimated at 0.41 g m −2 y −1 AFDW (ash free dry weight) (9.62 kJ m −2 y −1 ). Elimination production (E) (summation of losses) was estimated at 0.37 g m −2 y −1 AFDW (8.9 kJ m −2 y −1 ). The average annual biomass (B) was estimated at 0.073 g m −2 , resulting in a P/B ratio of 5.6 and an E/B ratio of 5.07.

The assemblages of peracarid crustaceans associated with the red alga Corallina elongata were studied from November 2006 to November 2007 in Rafraf, Tunisia (Mediterranean Sea). Monthly sampling yielded a total of 3593 individuals comprising 22 different species. The peracarids showed significant differences in mean density. Amphipoda were dominant in both numbers of individuals and species diversity. The amphipods Elasmopus pocillimanus, Caprella grandimana, and Stenothoe monoculoides were the dominant species and exhibited seasonal differences in density. The complex structure of C. elongata can provide a permanent refuge for peracarid Crustacea, and species such as the caprellid Caprella grandimana, in particular, seem to be are well adapted to this habitat. RÉSUMÉLes assemblages de Crustacés péracarides associés à l'algue rouge Corallina elongata ont été étudiés de Novembre 2006 à Novembre 2007 à Rafraf, Tunisie (Mer Méditerranée). Les échantillons mensuels contenaient un total de 3593 individus comprenant 22 différentes espèces. Les péracarides montrent des différences significatives dans leur densité moyenne. Les Amphipodes sont dominants à la fois en nombre et en diversité d'espèces. Les amphipodes Elasmopus pocillimanus, Caprella grandimana et Stenothoe monoculoides ont été les espèces dominantes et ont montré des différences saisonnières en densité. La structure complexe de C. elongata peut fournir un refuge permanent pour les Crustacés péracarides, et en particulier, les espèces telles que le caprellidé Caprella grandimana semblent bien adaptées à cet habitat. 1 )