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Marine plastic litter, originating from land-based sources, enters the marine environment by passing through coastal ecosystems such as lagoons and estuaries. As early life history stages (ELHS) of many commercially important fish species rely on these transitional areas as nursery grounds, we hypothesized that they encounter a spatial gradient of habitat quality and pollution from inner to outer parts of their vital environment. With sizes < 5 mm, anthropogenic particles (AP), among them microplastic (MP) fibers and fragments, entail a high bioavailability for ELHS of fish, potentially facilitating AP uptake at early developmental stages which may have implications for their survival and growth. This study provides a contextualization baseline between feeding preferences and uptake of AP by the white seabream Diplodus sargus (Linnaeus, 1758) in an estuarine nursery ground on the southern coast of Portugal. Juvenile fish showed a generalized, omnivorous feeding mode with differences in trophic resource utilization between individuals collected at distinct seagrass meadows in the lagoon. A total of 23.13% of the fish (n = 147) were detected with AP in the gastrointestinal tract, and the mean number of AP per AP-feeding individual was 1.64 ± 1.04, with anthropogenic fibers (n = 47) occurring more frequently than fragments (n = 9). Knowledge of the underlying factors for MP ingestion will be greatly enhanced by considering environmental conditions along with species-stage and life-stage specific feeding modes and prey preferences which shape the uptake probability of anthropogenic fibers and fragments. [ABSTRACT FROM AUTHOR]

The objective of this study was to use larval density data to investigate the temporal reproductive pattern and use of different biotopes of the Paraná River as areas of reproduction and the initial development of the migratory fish Salminus brasiliensis. During 15 reproductive periods (October to March) between 2001 and 2019, three biotopes (channel, tributary, and lake) of the upper Paraná River floodplain were sampled using conical-cylindrical plankton nets equipped with a flowmeter. The highest larvae densities were recorded between October and January, with a predominance of the pre-flexion and flexion stages captured mainly in the Paraná River channel. Larvae in the yolk-sac stage were most common in the tributaries. Temperature, pH, and rainfall were the main variables that influenced larval density. Our results showed that the reproduction of S. brasiliensis may have failed during a few reproductive periods and that the species uses different biotopes of the Paraná River for spawning and development, i.e., the tributaries and the river channels and lakes, respectively. Thus, providing conditions enabling a smooth migration to the tributaries for spawning as well as ensuring safe development in the river channels and lakes during their reproductive periods could help conserve this vulnerable species. Moreover, actions aimed at recovering the stocks of the species depend on the conservation of different floodplain environments and the maintenance of their original characteristics and on policies aimed to conserve the species, such as the prohibition of fishing. [ABSTRACT FROM AUTHOR]

Although many shark species display predictable and seasonal aggregations related to breeding activities, few studies have reported direct evidence of reproductive interactions of large sharks. In this context, the present study reports the first evidence of mating scars in female tiger sharks Galeocerdo cuvier at the Fernando de Noronha Archipelago (FEN), an oceanic remote insular system in the South Atlantic Ocean. Results from the records of seven wounded females suggest that mating activity may occur between February and August. These females measured between 267 and 372 cm in total length, which is aligned with previous studies reporting size at sexual maturity for Atlantic tiger sharks. Although some females exhibited healed wounds, three of them had fresh, open wounds. One of the females also had a swollen and red cloaca. We also report the first presumably gravid female tiger shark for the region. Although sporadic, the observations herein reported indicate the importance of FEN for tiger shark reproduction in western equatorial Atlantic waters. This finding is especially relevant as FEN has been identified as an important genetic hotspot for tiger sharks, with the largest global genetic diversity for the species. [ABSTRACT FROM AUTHOR]

The bentfin devil ray (Mobula thurstoni) is a migratory elasmobranch species with a wide distribution range. Despite the recent increase in mobulid research, critical habitats and home ranges are still being identified for these threatened species. In the present study, photo and video records opportunistically gathered by SCUBA diving effort were used to identify individuals and habitat usage by M. thurstoni in a marine protected area in the western equatorial Atlantic Ocean, Fernando de Noronha Archipelago (FNA). The bentfin devil ray was identified in five distinct records, in different years and sites around the archipelago. All the males showed developed claspers, suggesting mature individuals using the area. The UNESCO heritage site of FNA is considered an area of high biological importance, containing essential habitats for several species of fish, turtles and marine mammals. However, habitat usage by devil ray species is poorly reported in the region; therefore, the present study presents the first report of M. thurstoni at FNA, which adds the fifth mobulid ray species recorded in the region. Additionally, these results correspond to the second record of living specimens of M. thurstoni in Brazilian jurisdictional waters, highlighting new information on the species' distribution and the home range of mobulids in Brazil. [ABSTRACT FROM AUTHOR]

Cookiecutter sharks are pelagic ectoparasites that feed on pieces of flesh from large marine animals. Knowledge on these sharks is still rather scant, with the few existing works successfully using bites found on prey to reveal ecological patterns. This study aims to identify cookiecutter shark bite patterns on pelagic fishes in aggregated schools to gain an understanding of the ecology of these sharks. Data were collected by accompanying landings and onboard in tuna fishing vessels in the western equatorial Atlantic Ocean off Brazil. A total of 138 bite wounds were found on the bigeye tuna (Thunnus obesus), common dolphinfish (Coryphaena hippurus), skipjack tuna (Katsuwonus pelamis), and yellowfin tuna (Thunnus albacares). The most bitten species were the bigeye and yellowfin tuna, together accounting for 85% of all bites. Our findings offer novel insights into ectoparasitic ecology between cookiecutter sharks and pelagic fishes, identifying three major patterns: (i) preference of the sharks for the ventral surface of pelagic fishes; (ii) plasticity in biting tactics, with both bottom-up and lateral attacks; and (iii) habitat-dependent bite incidence (larger sharks commonly bite the skipjack tuna in epipelagic zones, whereas smaller sharks predominantly bite the bigeye tuna in mesopelagic zones). These results contribute to narrowing the gaps in knowledge on the ecology of the elusive, dwarf cookiecutter sharks. Further studies are needed for a better understanding of how shark-pelagic fish interactions are affected by the fishing of aggregated schools. [ABSTRACT FROM AUTHOR]