Eleven expeditions were undertaken to the Saint Peter and Saint Paul Archipelago to study the reproductive biology of Grapsus grapsus, providing additional information on limb mutilation and carapace colour. MATURE software was used to estimate morphological maturity, while gonadal analyses were conducted to estimate physiological maturity. The puberty moult took place at larger size in males (51.4 mm of carapace length) than in females (33.8 mm), while physiological maturity occurred at a similar size in males (38.4 mm) and in females (33.4 mm). Above 50 mm, the proportion of red males increased in the population, indicating that functional maturity is also related to colour pattern. Small habitat and high local population density contributed to the high rate of cannibalism. The low diversity of food items, absence of predators of large crabs and high geographic isolation are the determinants of unique behavioural and biological characteristics observed in the G. grapsus population.

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Ocean plankton comprise organisms from viruses to fish larvae that are fundamental to ecosystem functioning and the provision of marine services such as fisheries and CO2 sequestration. The latter services are partly governed by variations in plankton community composition and the expression of traits such as body size at community-level. While community assembly has been thoroughly studied for the smaller end of the plankton size spectrum, the larger end comprises ectotherms that are often studied at the species, or group-level, rather than as communities. The body size of marine ectotherms decreases with temperature, but controls on community-level traits remain elusive, hindering the predictability of marine services provision. Here, we leverage Tara Oceans datasets to determine how zooplankton community composition and size structure varies with latitude, temperature and productivity-related covariates in the global surface ocean. Zooplankton abundance and median size decreased towards warmer and less productive environments, as a result of changes in copepod composition. However, some clades displayed the opposite relationships, which may be ascribed to alternative feeding strategies. Given that climate models predict increasingly warmed and stratified oceans, our findings suggest that zooplankton communities will shift towards smaller organisms which might weaken their contribution to the biological carbon pump.

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Ichthyoplankton is an essential component of pelagic ecosystems, and environmental factors play an important role in determining its distribution. We have investigated simultaneous latitudinal and cross-shelf gradients in ichthyoplankton abundance to test the hypothesis that the large-scale distribution of fish larvae in the South Brazil Shelf is associated with water mass composition. Vertical plankton tows were collected between 21°27′ and 34°51′S at 107 stations, in austral late spring and early summer seasons. Samples were taken with a conical-cylindrical plankton net from the depth of chlorophyll maxima to the surface in deep stations, or from 10 m from the bottom to the surface in shallow waters. Salinity and temperature were obtained with a CTD/rosette system, which provided seawater for chlorophyll-a and nutrient concentrations. The influence of water mass on larval fish species was studied using Indicator Species Analysis, whereas environmental effects on the distribution of larval fish species were analyzed by Distance-based Redundancy Analysis. Larval fish species were associated with specific water masses: in the north, Sardinella brasiliensis was found in Shelf Water; whereas in the south, Engraulis anchoita inhabited the Plata Plume Water. At the slope, Tropical Water was characterized by the bristlemouth Cyclothone acclinidens. The concurrent analysis showed the importance of both cross-shelf and latitudinal gradients on the large-scale distribution of larval fish species. Our findings reveal that ichthyoplankton composition and large-scale spatial distribution are determined by water mass composition in both latitudinal and cross-shelf gradients.

The reproductive biology of Scyllarides deceptor was studied along the southern Brazilian coast (278S 488W) from December 2002 to December 2003. Samples were collected monthly at Xavier Island, where animals were caught and marked. Fecundity and egg size were estimated from ovigerous females caught also in two adjacent islands, Arvoredo and Aranhas. A total of 98 females was recorded at Xavier Island during the sampling period, 24 of these were recaptured and presented time-at-liberty ranging from 14 to 297 days. Ovigerous females were observed during spring and summer, with the moulting period lasting from late winter to spring. Size at sexual maturity was assessed from 66 females caught during the breeding season and estimated in 85.33 mm of carapace length (CL). Mean fecundity of S. deceptor was estimated in 191,262 eggs (+17,811, SE) for females, on average, 94.74 mm long (+1.86 mm SE) (CL). Fecundity was significantly related to CL (R 2 ¼ 0.90) Mean egg size was 0.67 mm (+0.005 mm SE) and did not correlate significantly to CL (P ¼ 0.78). The rocky bottom of Xavier Island was favourable for reproduction, presenting shelter and foraging grounds for the ovigerous females. For management purposes, our results suggest the closure of the S. deceptor fishery from November to January and the capture-size of females to be restricted to animals larger than 90 mm (CL).

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