Trait-based insights into sustainable fisheries: A four-decade perspective in Azores archipelago.

The trait-based approach provides a powerful perspective for analyzing fisheries and their potential impact on marine ecological processes, offering crucial insights into sustainability and ecosystem functioning. This approach was applied to investigate trends in fish assemblages landed by both local and coastal fishing fleets in the Azores archipelago over the past four decades (1980s, 1990s, 2000s, and 2010s). A matrix of ten traits was built to assess functional redundancy (Fred), functional over-redundancy (FOve), and functional vulnerability (FVul) for the fish assemblages caught by every fishing fleet in each decade. The susceptibility of the Azorean fishery to negative impacts on ecosystem functioning was evidenced by low FRed (<1.5 species per functional entity) and high FVul (exceeding 70 %). However, there is reason for optimism, as temporal trends in the 2000s and 2010s showed an increase in FRed and FOve along with a significant decrease in FVul. These trends indicate the adaptation of the fishery to new target species and, notably, the effectiveness of local fish regulations in mitigating the impacts of targeting functionally important species, such as Elasmobranchii, over the past two decades. These regulations have played a pivotal role in preserving ecological functions within the ecosystem, as well as in managing the removal of high biomass of key important species (e.g., Trachurus picturatus, Pagellus bogaraveo, and Katsuwonus pelamis) from the ecosystem. This study contributes to understanding the delicate balance between fishing pressure, ecological resilience, and sustainable resource management in Azorean waters. It also highlights the importance of continued monitoring, adaptive management, and the enforcement of local fishing regulations to ensure the long-term health and sustainability of the fishery and the broader marine ecosystem.

Climate change vulnerability assessment of the main marine commercial fish and invertebrates of Portugal.

This is the first attempt to apply an expert-based ecological vulnerability assessment of the effects of climate change on the main marine resources of Portugal. The vulnerability, exposure, sensitivity, adaptive capacity, and expected directional effects of 74 species of fish and invertebrates of commercial interest is estimated based on criteria related to their life-history and level of conservation or exploitation. This analysis is performed separately for three regions of Portugal and two scenarios of climate change (RCP 4.5 and RCP 8.5). To do that, the fourth assessment report IPCC framework for vulnerability assessments was coupled to the outputs of a physical-biogeochemical model allowing to weight the exposure of the species by the expected variability of the environmental variables in the future. The highest vulnerabilities were found for some migratory and elasmobranch species, although overall vulnerability scores were low probably due to the high adaptive capacity of species from temperate ecosystems. Among regions, the highest average vulnerability was estimated for the species in the Central region while higher vulnerabilities were identified under climate change scenario RCP 8.5 in the three regions, due to higher expected climatic variability. This work establishes the basis for the assessment of the vulnerability of the human activities relying on marine resources in the context of climate change.

Closely Related Fishes Inhabiting Different Ecosystems Exhibit the Same Oocyte Production and Recruitment Pattern.

Information on oocyte production and recruitment in phylogenetically related species can help in understanding the evolution of reproductive life-history traits in fish of indeterminate fecundity. The present study compared, for the first time, oocyte production and recruitment patterns between two closely related species: Stellifer brasiliensis and Stellifer rastrifer (Perciformes, Sciaenidae), in the southwestern Atlantic, Brazil. Specimens of S. brasiliensis were sampled from the coastal waters of Ubatuba, and samples of S. rastrifer were taken from the Cananéia Lagoon Estuarine System. Ovaries were investigated using histology and model-based stereology. The total number of oocytes per individual (N) and stage-specific oocyte packing density did not differ significantly between S. brasiliensis and S. rastrifer The number of pre-vitellogenic and vitellogenic oocytes were positively correlated with female total weight and length, and ovary weight in both species. Analysis of oocyte recruitment across their development stages revealed that approximately 5.9% of the standing stock oocytes larger than 50 µm in S. brasiliensis and 5.0% in S. rastrifer were recruited to form the next batches. Females of S. brasiliensis and S. rastrifer, in spawning-capable phase, exhibit the same oocyte production and recruitment patterns, showing no influences of the ecosystems on primary and secondary oocyte production.