Plastics in scene: A review of the effect of plastics in aquatic crustaceans.

Plastic pollution in aquatic environments is present in all compartments from surface water to benthic sediment, becoming a topic of emerging concern due to the internalization, retention time, and its effects on aquatic biota. Crustacea with nearly 70,000 species, broad distribution and different roles in the trophic webs is a significant target of the increasing plastic pollution. At least 98 publications in the last 10 years report the impact of plastics in crustaceans, all suggesting that this taxon is at high risk for ecosystem disadvantage by plastic contamination loads. This review compiles the current knowledge on physiological effects (endpoints) by plastic contamination analyzed in crustaceans in the last 10 years, highlighting their use as model species for ecotoxicological tests, sentinels species and bioindicators. Plastic contamination analyzed in this review includes macroplastic, microplastic, and nanoplastic, in a wide variety of types. The studies were focused on 38 marine species with an economic interest in fisheries and aquaculture; 14 freshwater with a higher frequency in standard test species and 4 estuarial and 3 mangrove species with ecological interest. The publications reviewed were divided into studies describing plastic presence in crustaceans without reporting toxic effects and those with analysis of plastic toxicity. Publications describing the plastic presence in the organisms show that the ingestion in individual effects and food-web transfer in ecological effects were the most frequent endpoints. The publications that analyzed plastic toxicity through survival, nutrition-metabolism-assimilation, and reproduction in individual effects, and bioaccumulation in ecological effects were the most frequent endpoints. This review gathers the available information on the use of crustaceans as model species in environmental impact for toxicity screening and hazard assessment. Besides, identifying knowledge gaps will let us propose some future directions in research and the effects on target fisheries species which involves a possible effect on human health.

Comparative reproductive effort and fecundity in the spider crabs, Leurocyclus tuberculosus and Libinia spinosa (Majoidea, Brachyura).

A comparative analysis of reproductive effort, fecundity, and egg weight was conducted in two species of spider crabs, Leurocyclus tuberculosus and Libinia spinosa, during one-year period. Ovigerous females were collected from Patagonia-Argentina (42°56'S, 64°21'W) and were measured (CW = carapace width). Each egg brood was weighed, dried and the number of eggs (F = fecundity) counted. Scatterplots of relative fecundity (RF = F/CW) were submitted to regression analyses. Mean F and RF was calculated for each season to assess seasonal variation of reproductive intensity. Mean F was 35,000 eggs in L. tuberculosus and 30,000 eggs in L. spinosa, with these values being intermediate in comparison with other Majoidea. The RF was approximately 18% higher in L. tuberculosus that presented an average dry weight egg 45% less than L. spinosa. Although in both species F showed a positive correlation with CW, less than the 20% of the variation in the number of eggs could be explained by female's size, suggesting there are other factors that influence F. The proportion of body energy devoted to reproduction (reproductive effort), exhibited significant differences between species. In Leurocyclus tuberculosus reproductive activity is significantly different along the 12-month suggesting that the conditions for 'optimal' egg production change throughout the year. In Libinia spinosa mean fecundity did not reveal significant differences over seasons. These results are central in studies of life-history theory and in the development of life history models, as it is directly related to energy allocation and partitioning.

Differential toxicity of copper, zinc, and lead during the embryonic development of Chasmagnathus granulatus (Brachyura, Varunidae).

Ovigerous females of the estuarine crab Chasmagnathus granulatus were exposed to copper (0.01 and 1 mg/L), zinc (0.05, 1, and 10 mg/L), or lead (0.01 and 1 mg/L) during early, late, or whole embryonic development. None of the assayed heavy metals produced a significant mortality of females, neither a decrease in the number of hatched larvae nor a decrease in the egg incubation time, but several morphological abnormalities were detected in hatched larvae. The abnormalities were classified in three categories: eye, body pigmentary, and body morphological abnormalities. Those larvae with eye and body pigmentary abnormalities, particularly those involving retinal pigments and chromatophores, showed the highest incidence by exposure to the assayed metals. In addition, embryos were more susceptible to copper and zinc during the late period of development, whereas the effect of lead was greater during the early period of embryogenesis. Some teratogenic effects observed in C. granulatus embryos exposed to heavy metals, particularly the hypertrophy and hypopigmentation of eyes observed in the laboratory at a lead concentration as low as that reported for the natural environment, could be considered as sensitive biomarkers for this kind of pollutant.