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Harvested populations of the sea urchin (Paracentrotus lividus) from the northwestern (Carreço) and southwestern (Aljezur) coasts of Portugal were surveyed to describe the species reproductive cycle and assess possible relationships with geographical location and seawater temperature. Individuals were sampled monthly to analyze gonad histology, mean gonadal index (GI), and gonadosomatic index (GSI) during 2 consecutive years (November 2010–November 2012). Both populations presented an annual reproductive cycle, with synchronous gonad maturation and gamete release between sexes. Gonad maturation occurred throughout autumn–winter, followed by a single but prolonged spawning season during spring–summer. The duration of the spawning season displayed a latitudinal gradient likely related to the north–south increasing trend in seawater temperature, with the northwestern population (Carreço) exhibiting a shorter spawning period compared to the southwestern population (Aljezur). The timing and duration of the spawning season was compared with several populations throughout the distributional range of P. lividus in the Atlantic Ocean and Mediterranean Sea. In the population from Carreço, the size at first sexual maturity (test diameter = 35.9 mm) was considerably smaller than the minimum conservation reference size (MCRS) of 50 mm test diameter legally established for P. lividus. This study confirms that sustainable exploitation depends on harvesters’ awareness of and compliance with the MCRS and provides useful information for the eventual establishment of a closed season in the harvesting of P. lividus.

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The present study provides updated information on amphipod assemblages of the southern Portuguese coast, the most south-western part of continental Europe. The inXuence of depth and sediment type on the spatial distribution of shallow soft-bottom amphipods was tested by means of univariate and multivariate methods. Samples were collected down to 40 m depth within areas ranging from very Wne sand to gravel. The ratio between density and diversity was found to increase with depth and from coarser to Wner sediments. Both physical variables tested were found to play a major role in structuring amphipod assemblages. However, some dominance of depth was evident as samples were mainly separated according to this variable. Moreover, while only 15 taxa were common to all depth levels, 35 were collected from all sediment types. Both depth and sediment type may override the potential eVects of geographical location, as samples from diVerent areas along the southern Portuguese coast were biologically related. A peculiar habitat was sampled in this study: a maerl bed, which was conWrmed to be a hotspot of density. Nevertheless, this habitat did not harbor a distinct amphipod assemblage but some taxa such as Caprella spp., Lembos websteri, lysianassids and Gammarella fucicola were preferentially collected there. The biogeographical analysis pointed out the occurrence of 8% of Mediterranean endemic species, conWrming the inXuence of the Mediterranean Sea beyond the Strait of Gibraltar, and the AtlanticMediterranean feature of the amphipod fauna of this geographically relevant area. The present results support the need to interpret the spatial distribution patterns of marine species in relation to the combined eVect of depth and sediment characteristics.

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