Distribution and size of the mojarra Diapterus rhombeus (Cuvier) (Actinopterygii, Gerreidae) in a Southeastern Brazilian bay

Diapterus rhombeus é uma das espécies de peixes mais abundantes na Baia de Sepetiba, ambiente costeiro de 520 km² de área semifechada no sudoeste do Brasil. O tamanho e distribuição dos indivíduos desta espécie foram descritos com o objetivo de determinar o uso das áreas de criação numa dimensão espacial e temporal (sazonal). Um programa de amostragem de arrasto de fundo foi conduzido mensalmente entre outubro 1998 a setembro 1999, em três zonas da baía (externa, central, interna), definidas através de gradientes de profundidade e salinidade. Diferenças altamente significativas foram encontradas para CPUEs (número e biomassa) entre estações do ano e zonas. O comprimento variou de 50 a 230 mm CT. Três grupos de tamanhos foram definidos de acordo com uma escala de maturação gonadal (n = 1435): 1 - imaturo (< 80 mm Comprimento Total - CT); 2- indivíduos em primeira maturação (L50) (80-90 mm CT); e 3 - adultos (L100) (&gt; 100 mm CT). Imaturos e indivíduos L50 foram abundantes (número e biomassa) durante o outono na zona interna, enquanto adultos (L100) predominaram durante o verão na zona externa. Evidências de movimento de indivíduos jovens (50-90 mm CT) da zona interna para zona externa foram detectadas conforme os animais foram atingindo maiores tamanhos (180 mm CT), no segundo ano de vida. A condição (k) aumentou em indivíduos maiores na zona externa durante a primavera, quando estes se tornam aptos a iniciar o processo reprodutivo. Duas coortes foram detectadas de acordo com a progressão modal: a primeira (menores tamanhos) mostrando crescimento mais rápido do que a segunda, evidenciando uma taxa menor de crescimento a medida que atingem maiores tamanhos. Diferentes classes de comprimento ocupando diferentes zonas da baía sugerem que grupos de idades otimizam sua coexistência compartilhando os recursos disponíveis e evitando competição intra-especifica.Diapterus rhombeus is one of the most abundant fish species in the Sepetiba bay, which is a 520 km² semi-closed coastal area in Southeastern Brazil. The size and distribution of this species have been described in order to assess the use of the area as a rearing ground in both spatial and temporal (seasonal) dimensions. A fish sampling program was conducted monthly by using an otter trawl between October 1998 and September 1999, in three bay zones (outer, middle and inner), defined according to depth and salinity gradient. Highly significant differences were found for CPUEs (number and biomass) among seasons and zones. Size ranged from 50 to 230 mm TL, and three size-groups were defined according to a maturation scale (n = 1435): 1 - immature (< 80 mm Total Length - TL); 2- individuals at the first maturation (L50) (80-90 mm TL), and 3 - adults (L100) (&gt; 100 mm TL). Immature and L50 individuals were more abundant (number and biomass) during Autumn in the inner zone, while adults (L100) predominated during Summer in the outer zone. Evidences of movements of young-of-the-year (50-90 mm TL) individuals from the inner to the outer zone were detected as they reach larger sizes (180 mm TL) in the second year of life. Condition (k) was higher in larger sized individuals in the outer zone during Spring, when they are apt to start the reproductive process. Two cohorts were detected according to modal progression: the first (smaller size) showing faster growth than the second, evidencing a slower growth rate as they reach larger size. Distinct size classes occupying different bay zones suggest that the age-groups optimize their coexistence by partitioning the available resources, avoiding intra-specific competition

Effects of a nuclear power plant thermal discharge on habitat complexity and fish community structure in Ilha Grande Bay, Brazil

International audienceFish communities and habitat structures were evaluated by underwater visual censuses a rocky location impacted by thermal discharge (I) and at two control locations, one in a bed (C1) and the other in a rocky shore with higher structural complexity (C2). Habitat indicators and fish communities exhibited significant differences between the impacted and control locations, with the impacted one showing a significant decrease in fish species richness and diversity, as well as a decrease in benthic cover. At the I location, only 13 fish species were described, and the average water temperature was 32 ± 0.4 °C, compared with 44 species at C1 (25.9 ± 0.3 °C) and 33 species at C2 (24.6 ± 0.2 °C). Significant differences in fish communities among locations were found by ANOSIM with , sp and typical of location I, while and were typical of the control locations. Our study shows that thermal pollution alters benthic cover and influences fish assemblages by altering composition and decreasing richness

Erythropodium caribaeorum (Duchassaing and Michelotti, 1860) (Cnidaria Alcyonacea), an additional alien coral in the Southwestern Atlantic

Carpinelli, Ágatha Nascimento, Cordeiro, Ralf Tarciso Silva, Neves, Leonardo Mitrano, Moura, Rodrigo Leão De, Kitahara, Marcelo Visentini (2020): Erythropodium caribaeorum (Duchassaing and Michelotti, 1860) (Cnidaria Alcyonacea), an additional alien coral in the Southwestern Atlantic. Zootaxa 4822 (2): 175-190, DOI: https://doi.org/10.11646/zootaxa.4822.2.

Effects of marine protected areas under different management regimes in a hot spot of biodiversity and cumulative impacts from SW Atlantic

Marine protected areas (MPAs) represent a useful tool for resource management, as well as to conserve and/or restore biological communities. The level of protection is key factor influencing the marine biodiversity, where a more enforced protection is expected to drive positive outcomes. In 2008, a large MPAs network ( 11,380 km 2) was established in one of off the most populated and industrialized areas in the world (i.e., São Paulo State coast, southeast Brazil). Given many goods and services provided by marine ecosystems, this MPA network represents the most challenging marine conservation initiative in Brazil. Harboring​ areas with different socio-ecological contexts and management regimes, this MPA network provides a unique opportunity to investigate the effects of cumulative impacts. We contrasted the biomass and size structure of reef fish in three subtropical islands under different levels of enforcement. We analyzed the influence of variables as island size, benthic cover, depth, topographic complexity, wave exposure, and protection level on the biomass of reef fish assemblages. Protection level was the main attribute responsible to explain the high biomass of fish target species and small territorial herbivores. In sites sheltered from the waves, the biomass of groupers was 1600% higher within enforced area than that from open-access area. Beyond the idea of positive effects of enforcement on reef fish biomass and size, we add evidences that even under multiple stressors, the area-based management is still a strong tool to marine conservation.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP: 2019/19423-5FAPESP: 2017/22273-