Sexual Maturity of an Endemic Insular Land Crab: Priority Information toward the Conservation of Johngarthia lagostoma.

AbstractInsular land crabs (Gecarcinidae) can transit between terrestrial and aquatic environments and inhabit vacant ecological niches that other species do not occupy in oceanic islands. During the reproductive period, these crabs migrate between residential and reproductive areas; this is a critical moment because individuals are more vulnerable to stressful conditions, especially species occupying anthropized islands. Currently, many insular crab species are considered threatened; yet few studies have evaluated the biology of this group, especially the size at which individuals reach sexual maturity. Here, we evaluate the size at the onset of morphological, physiological, and functional maturity for the insular land crab Johngarthia lagostoma in Trindade Island (Brazil) and assess the chronology of the events underlying those processes. Males and females exhibited the same order of occurrence of the different maturity processes, starting by being morphologically, physiologically, and, finally, functionally mature at similar sizes (about 56 mm carapace width). This value corresponds to at least half of the maximum size that J. lagostoma reaches in Trindade Island and is close to the average relative value registered to other Gecarcinidae species. Considering the current decline in the population of insular crabs, such estimates can be used in management programs, mainly for the definition and protection of breeding and recruitment areas. Specifically, our results can be used toward the conservation of J. lagostoma, which is currently classified as endangered in Brazil, especially in the isolated population of Trindade Island.

Genomic damage in Mugil curema (Actinopterygii: Mugilidae) reveals the effects of intense urbanization on estuaries in northeastern Brazil.

The largest metropolitan centers in northeastern region of Brazil are all located near the coast, and industrial, tourist, and agro-industrial activities are the principal causes of water contamination due to discharges of untreated sewage. Adverse environmental conditions can often be detected by analyzing the genetic material of organisms exposed to pollutants, and furnish an overview of environmental quality. We evaluated possible damage to the DNA of one of the fish resources most widely consumed and commercialized by coastal communities in northeastern Brazil, Mugil curema ("tainha"). Erythrocytes from M. curema were analyzed by the presence of micronuclei and by comet assay (single cell gel electrophoresis, SCGE). Statistical comparisons to both tests revealed considerably greater genomic damage in polluted estuaries than in the control site (p < 0.05), suggesting strong genotoxic impacts on the specimens evaluated, principally among those taken near localities with dense demographic and industrial development.

Density, abundance and extractive potential of the mangrove crab, Ucides cordatus (Linnaeus, 1763) (Brachyura, Ocypodidae): subsidies for fishery management.

Ucides cordatus is a relevant fishery resource of Brazilian mangroves and requires legal normative to sustainable use based on stock assessment and management. This study evaluated some population parameters (structure, density, abundance, fishery potential and stock) of this crab species in Brazil Southeast (São Paulo, State), discussing the use of the results to delineate fishery management strategies. Density was monthly evaluated (September 1998 to August 1999), using five sample quadrats of 2x2 m. Density (ind.m-2) was indirectly estimated by counting the opened (with biogenic activity) and closed galleries, and contrasted with flooding level by tides using the vertical distribution of macroalgae in the base of trees. Density of U. cordatus ranges from 2 to 11 ind.m-2 (6±2 ind.m-2) and statistical difference occurred among monthly means (F=11.58; p=0.000). The relationship density vs. tidal flooding indicated a decrease of U. cordatus density in mangroves with higher levels of tidal flooding (r=-0.94; p=0.001). The total abundance of U. cordatus was estimated in 63.7 millions of crabs in 10.61 km2, with a reduction of 34.9% due to total mortality discount. Estimates like that are uncommon in literature, and could be used for fishery forecasts, allowing improvement by the introduction of new variables to be known in the future.

Physiological differences in the crab Ucides cordatus from two populations inhabiting mangroves with different levels of cadmium contamination.

Crustaceans found in metal-contaminated regions are able to survive, and the authors investigated the physiological mechanisms involved by comparing populations from contaminated and noncontaminated areas. The objective of the present study was to measure the cellular transport of a nonessential metal (cadmium [Cd]) in gills and hepatopancreas of Ucides cordatus, together with cell membrane fluidity, metallothionein levels, and lipid peroxidation. The 2 populations compared were from a polluted and a nonpolluted mangrove area of São Paulo State, Brazil. The authors found, for the first time, larger Cd transport in gills and hepatopancreatic cells from crabs living in polluted mangrove areas. The cells also had lower plasma membrane fluidity, increased lipid peroxidation and less metallothionein compared to those from nonpolluted regions. The authors also found larger amounts of Cd in intracellular organelles of gills, but not in the hepatopancreas, from crabs in polluted regions. Therefore, in polluted areas, these animals showed higher Cd transport and lower plasma membrane fluidity and storage of Cd intracellularly in gill cells, whereas hepatopancreatic cells used metallothionein as their main line of defense. The findings suggest that crabs from polluted areas can accumulate Cd more easily than crabs from nonpolluted areas, probably because of an impairment of the regulatory mechanisms of cell membrane transport. Environ Toxicol Chem 2017;36:361-371. © 2016 SETAC.

Reproduction and management of the mangrove crab Ucides cordatus (Crustacea, Brachyura, Ucididae) at Iguape, São Paulo, Brazil.

The mangrove crab Ucides cordatus is one of the most exploited crustaceans in Brazil. The present study investigated the breeding season of this species and the period of the "andada" phenomenon, when the crabs are active outside their burrows and perform agonistic behaviors. Furthermore related them to environmental factors, in a mangrove on the coast of Brazil, with inferences about management of this crab. The crabs reproduced from October through February. The "andada" occurred from November through February, with typical characteristics in the first two months, during the full and new moon periods, and was influenced positively by the air and soil temperature, luminosity, and tidal amplitude, and negatively by salinity. Based on the results of the present study, the period when the "andada" occurs in other parts of Brazil could be defined, which will aid in managing this fishery. For Iguape, state of São Paulo, Brazil, we suggest a legal off-season for both sexes in December or during the full and new moon, including January.