RESUMO
We studied the spawning ecology of Stegastes sanctipauli, a damselfish endemic to the small and remote St Peter and St Paul's Archipelago (Brazil), aiming to determine the main correlates of reproductive success, as inferred from rates of egg losses along a spawning season. New clutches appeared mostly in the last quarter moon, when egg predation intensified. Predation by heterospecifics, particularly Halichoeres radiatus (Linnaeus, 1758), accounted for most egg losses, while filial cannibalism showed negligible influence. Predation pressure was highest for larger nests with higher initial density of eggs. Hatching of eggs occurred close to the new moon (i.e., ~5 days after spawning). Most nests occur in shallow reefs (<16 m depth), where main food resources for adults (turf algae) are concentrated, but abundance of egg predators, particularly H. radiatus, is also highest. This latter result suggests that the spawning activity of S. sanctipauli is influenced by the trade-offs between food accessibility by adults and egg predation risk. The patterns recorded here are similar to those known for other tropical damselfish species and may reflect strategies for attenuating predation pressure over new fry and eggs.
Assuntos
Ecologia , Perciformes , Animais , Canibalismo , Reprodução , Comportamento PredatórioRESUMO
Many shark populations are in decline around the world, with severe ecological and economic consequences. Fisheries management and marine protected areas (MPAs) have both been heralded as solutions. However, the effectiveness of MPAs alone is questionable, particularly for globally threatened sharks and rays ('elasmobranchs'), with little known about how fisheries management and MPAs interact to conserve these species. Here we use a dedicated global survey of coral reef elasmobranchs to assess 66 fully protected areas embedded within a range of fisheries management regimes across 36 countries. We show that conservation benefits were primarily for reef-associated sharks, which were twice as abundant in fully protected areas compared with areas open to fishing. Conservation benefits were greatest in large protected areas that incorporate distinct reefs. However, the same benefits were not evident for rays or wide-ranging sharks that are both economically and ecologically important while also threatened with extinction. We show that conservation benefits from fully protected areas are close to doubled when embedded within areas of effective fisheries management, highlighting the importance of a mixed management approach of both effective fisheries management and well-designed fully protected areas to conserve tropical elasmobranch assemblages globally.
Assuntos
Conservação dos Recursos Naturais , Recifes de Corais , Pesqueiros , Tubarões , Rajidae , Animais , Conservação dos Recursos Naturais/métodosRESUMO
Serranus aliceae n. sp. is described from Rio de Janeiro and Espírito Santo States, southeastern Brazilian coast. The species is readily distinguished from its congeners by the following combination of characters: scales around the caudal peduncle 20 or 21; total gill rakers on first branchial arch 23-29; cheek-scales rows 5 or 6; and by the coloration of live specimens, which are reddish with a broad, conspicuous, white stripe from post-orbital region to the caudal-fin base and a white abdomen. The new species apparently inhabits the deeper (30 or more meters) portions of reef environments along the subtropical Brazilian coast, and is possibly associated with upwelling cold-water masses. The species was observed hovering above rocky bottoms, feeding on micro-crustaceans, squid larvae, and zooplankton. This new species increases to eight the number of valid Serranus species recorded in the southwestern Atlantic.
Serranus aliceae sp. n. é descrita do Rio de Janeiro e Espírito Santo, costa sudeste do Brasil. Esta espécie é facilmente distinguível de suas congêneres pela seguinte combinação de caracteres: escamas ao redor do pedúnculo caudal 20 ou 21; rastros no primeiro arco branquial 23-29; 5 ou 6 séries de escamas na bochecha e pelo colorido de espécimes vivos, que têm corpo avermelhado com uma larga e evidente faixa branca que se estende da região pós-orbital à base da nadadeira caudal, e o ventre branco. A espécie nova aparentemente habita a parte profunda (30 metros ou mais) de ambientes recifais ao longo da costa subtropical brasileira, e possivelmente está associada a áreas de ressurgência. A espécie foi observada pairando acima de fundos rochosos, alimentando-se de microcrustáceos, larvas de lulas e zooplâncton. Esta espécie nova aumenta para oito o número de espécies válidas de Serranus registradas no Atlântico Sudoeste.