Algarve Centre for Marine Sciences

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Publications

Marine recreational fishing in Portugal: current knowledge, challenges, and future perspectives

Publication . Diogo, Hugo; Veiga, Pedro; Pita, Cristina; Sousa, A.; Lima, David; Pereira, João Gil; Gonçalves, Jorge M.S.; Erzini, Karim; Rangel, Mafalda

Marine recreational fishing (MRF) in Portugal is a traditional leisure activity with considerable importance for coastal populations. In the absence of available information from the national data collection framework, this article aims to review the existing information on MRF across the country. MRF was an open access fishery until recently, but with rising evidence of overexploitation of coastal resources, a precautionary approach was imposed topdown, without consulting recreational fishers. In Portugal, the MRF participation rate is comparable to the European average (2%). The most important fishing mode (according to the official issued licenses) is shore angling. Mainland Portugal marine recreational catches (0.8% of total commercial landings) are likely underestimated, while the estimate for the Azores (6% of total commercial landings) is probably closer to the national reality. The Portuguese MRF sector faces several challenges, including: (1) the need for a definition of a national data collection framework; (2) the inclusion of MRF harvest estimates in stock assessments for key captured species; (3) management approaches which also take into account the ecosystem approach to fisheries and any potential effects of climate change; (4) additional research on post-release mortalities for the most important MRF species; and (5) a stronger involvement of all stakeholders in the decision-making process of MRF. The latter would be critical to improve the adequacy of regulations to the MRF reality, mitigate conflicts with other sectors (e.g., commercial fishing), and potentially increase fishers compliance.

2020Journal article

Open access

Niche and neutral assembly mechanisms contribute to latitudinal diversity gradients in reef fishes

Publication . Bosch, Nestor E.; Wernberg, Thomas; Langlois, Tim J.; Smale, Dan A.; Moore, Pippa J.; Franco, João N.; Thiriet, Pierre; Feunteun, Eric; Ribeiro, Cláudia; Neves, Pedro; Freitas, Rui; Filbee-Dexter, Karen; Norderhaug, Kjell Magnus; Garcia, Alvaro; Otero-Ferrer, Francisco; Espino, Fernando; Haroun, Ricardo; Lazzari, Natali; Tuya, Fernando

Aim: The influence of niche and neutral mechanisms on the assembly of ecological communities have long been debated. However, we still have a limited knowledge on their relative importance to explain patterns of diversity across latitudinal gradients (LDG). Here, we investigate the extent to which these ecological mechanisms contribute to the LDG of reef fishes. Location: Eastern Atlantic Ocean. Taxon: Reef-associated ray-finned fishes. Methods: We combined abundance data across ~60° of latitude with functional trait data and phylogenetic trees. A null model approach was used to decouple the influence of taxonomic diversity (TD) on functional (FD) and phylogenetic (PD) diversity. Standardized effect sizes (SES FD and SES PD) were used to explore patterns of overdispersion, clustering and randomness. Information theoretic approaches were used to investigate the role of large-(temperature, geographic isolation, nitrate and net primary productivity) and local-scale (human population and depth) drivers. We further assessed the role of demographic stochasticity and its interaction with species trophic identity and dispersal capacity. Results: Taxonomic diversity peaked at ~15°–20° N, with a second mode of lower magnitude at ~45°N; a pattern that was predicted by temperature, geographic isolation and productivity. Tropical regions displayed a higher proportion of overdispersed assemblages, whilst clustering increased towards temperate regions. Phylogenetic and functional overdispersion were associated with warmer, productive and isolated regions. Demographic stochasticity also contributed largely to community assembly, independently of ecoregions, although variation was dependent on the trophic identity and body size of species. Main conclusions: Niche-based processes linking thermal and resource constraints to local coexistence mechanisms have contributed to the LDG in reef fishes. These processes do not act in isolation, stressing the importance of understanding interactions between deterministic and stochastic factors driving community structure in the face of rapid biodiversity change.

2021Journal article

Restricted access

Dynamics of Decapoda larvae communities in a southwest Iberian estuary: Understanding the impact of different thermal regimes

Publication . Monteiro, Marta; Cruz, Joana; Azeiteiro, Ulisses; Marques, Sónia Cotrim; Baptista, Vânia; Teodosio, Maria Alexandra

Environmental conditions play a pivotal role in shaping the dynamics of meroplanktonic communities, which represent a vital life stage, crucial for successful recruitment. Specifically, temperature can impact the survival and duration of larval development in decapod crustacean species. The objective of this study is to analyze the community of decapod larvae in the Guadiana estuary, located in southwest Iberia. The analysis focuses on the community's taxonomic composition, temporal variability, and the influence of environmental factors. Particularly, the study emphasizes investigating the impacts of different thermal regimes on the abundance of these assemblages. A comprehensive zooplankton sampling program was conducted at a single station in the lower estuary, from 2014 to 2022. The decapod larvae assemblages are dominated by Upogebia spp., followed by Diogenes pugilator, Panopeus africanus, Afropinnotheres monodi, and Polybius henslowii species. The results of structural equation modeling unveiled a strong influence of water temperature and salinity on the community, while chlorophyll-a concentration, river runoff, and the large-scale climatic mode North Atlantic Oscillation (NAO) revealed no impact on the abundance of these assemblages. Overall, the community and the main taxa displayed a positive linear trend in response to increased salinity. However, the effect of increasing temperature varied among species. In the current climatic scenario, water temperature emerges as a critical factor in predicting seasonal variation of the assemblages' abundances, exhibiting a marked seasonality during spring and summer. Predictive models used to investigate future scenarios, Representative Concentration Pathway (RCP) 2.6 and RCP 8.5, defined by the International Panel on Climate Change (IPCC), where the temperature is expected to rise 2 °C and 4.3 °C by 2100, suggest the possibility for an alteration in assemblages' composition, where the abundances of D. pugilator, the second most abundant species, tend to decrease abruptly. Reported evidence, coupled with the typical Mediterranean climate of the region, where extreme climatic events, like marine heatwaves, are becoming more frequent, the high connectivity with the Mediterranean Sea, where invasion by non-indigenous species is increasing, also connected with changes in freshwater discharges, may trigger significant alterations in species dominance and abundance, with ecological and socio-economic implications.

2023Journal article

Restricted access