Weight^length relationships of some of the most abundant bivalve species from the Algarve coast (southern Portugal) captured during several exploratory ¢shing surveys carried out during 2000 on a soft bottom in the subtidal zone down to 25 m depth are reported. For this study a total of 7429 individuals were sampled, belonging to 25 bivalve species in nine families. The most represented families were Mactridae and Veneridae with six species, immediately followed by the families Cardiidae (¢ve species) and Donacidae (three species). The results revealed that most species presented isometric (11 species) or positive allometric relationships (11 species), while only a small minority of species displayed negative growth (three species). 39.75 AE13.43 (5.74^60.46) W0.00005L 3.097 0.964** 0.071 (2.955^3.239) isometric Family Cardiidae Acanthocardia aculeata 210 37.26 AE16.86 (11.30^95.97)

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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.