Climate-mediated shifts in marine resources: an eco-socio-economic approach to assess vulnerability of fisheries to Climate Change.

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A bayesian approach to infer the sustainable use of artificial reefs in fisheries and recreation

Publication . Ramos, Jorge; Drakeford, Benjamin; Madiedo, Ana; Costa, Joana; Miguel de Sousa Leitão, Francisco

The presence of artificial reefs (ARs) in the south of Portugal that were deployed a few decades ago and the corroboration of fishing patterns and other activities related to the use of these habitats have not been followed. It is important to note that monitoring the use of ARs was difficult in the past but is currently facilitated by the application of non-intrusive tools. In the present study, an approach is developed where, based on monitoring data from fishing and non-fishing boats, influence diagrams (IDs) are constructed to provide some evidence on fisheries or other use patterns and consequent AR effectiveness as coastal tools. These IDs allow us to infer various usefulness scenarios, namely catches, which are tangible, and satisfaction, which is intangible, and overall assessment of ARs and nearby areas in terms of human activities. After calibrating the Bayesian ID based on monitoring evidence, the obtained model was evaluated for several scenarios. In the base case, which assumes the occurrence of more fishing than recreation (assuming 3:1, respectively), the obtained utility is 18.64% (catches) and 31.96% (satisfaction). Of the scenarios run, the one that obtained the best results in the utility nodes together was the second one. The use of these tailored tools and approaches seems to be of fundamental importance for the adequate management of coastal infrastructures, particularly with regard to the inference of fishing resources and their sustainable use. An adequate interpretation based on the use of these tools implies being able to safeguard the ecological balance and economic sustainability of the communities operating in these areas.

2024-01-17Journal article

Open Access

Eco-socio-economic vulnerability assessment of Portuguese fisheries to climate change

Publication . Pinto, Miguel; Albo-Puigserver, Maria; Bueno-Pardo, Juan; N. Monteiro, J.; Teodosio, Maria; Leitão, Francisco

Understanding ecological, and socio-economical vulnerabilities is fundamental towards developing and implementing regional adaptation strategies to climate change. The Portuguese coast is situated in a transition zone between temperate ecosystems to the north, and subtropical with Mediterranean characteristics, to the south, with distinct oceanographic regions (north, centre, and south), fish assemblages and socioeconomic realities of fish communities across these regions. We develop a framework to assess fisheries climate vulnerability in each port. A total of 32 ecological and socio-economic indicators were used to measure exposure, sensitivity, and adaptive capacity of the fishing sector to climate change by combining i) environmental projections ii) information from fishing communities (surveys at ports) and iii) landings and socio-economic data from official statistics offices. The vulnerability to climate change across regions, and its expected impact on fishing fleets and local communities, was low-moderate. Such information will enable fishing communities and decision makers to respond to expected climate change effects and direct/indirect associated activities. This framework comprises background information for developing mandatory EU climate adaptation plans that aim to improve the resilience of fisheries socio-economic systems.

2023-10Journal article

Open Access

Reproductive traits of the African mud crab (Panopeus africanus) on the South Portuguese coast

Publication . N. Monteiro, J.; Ovelheiro, Andreia; Pinto, Miguel; Teodosio, Maria; Leitão, Francisco

Species with high economic relevance are widely studied in contrast with low economic relevance species such as Panopeus africanus, a small crab with a wide distribution along the eastern Atlantic coast, which remains poorly studied in regarding to the biological and ecological issues. Knowledge of reproductive patterns is essential to understand populations dynamics and species biological life-cycle traits. The main objective of the present research was to study the reproductive patterns of P. africanus. The population size structure, maturation stages and gametogenic development aspect, size at maturation, reproductive periods and morphometric-fecundity relationships of P. africanus in the southern Portuguese coast (Ria Formosa) was analysed. Crabs were sampled monthly, from January 2019 to December 2021, with traps and hand collected. The crab's carapace width (CW) ranged between 7 to 52 mm, and it was observed that in smaller and larger CW size classes, the proportion of males was higher, however in intermediate CW size classes the sex ratio was near 1:1. The gonads development was characterized based on histological analysis. Males presented four maturity developmental stages where two stages were immature and two were mature. Females presented six maturity developmental stages, where two stages were immature, and four stages were mature. Regardless of sex, the mean maturity size was 20 mm CW. A high percentage of mature individuals was observed throughout the year however, in the colder months the percentage of mature individuals was lower. Additionally, ovigerous females were only observed in the warmer months, pointing to a short breeding period occurring in the warmer months. Fecundity ranged between 12368 and 84140 eggs/female, following a positive correlation between CW/egg number. These novel results allowed to shed light on reproductive patterns of P. africanus population inhabiting the southern Portuguese coast, contributing also to a better understanding of the basic reproductive biology of this crab populations.

2024Journal article

Open Access

Characterising different artisanal fishing gears catches that operate in distinct habitats to assess ichthyofauna assemblages in Bons Sinais estuary, Mozambique

Publication . Jeremias J. Mocuba; Eudriano F.S. Costa; Daniel Oliveira Mualeque; Maria Alexandra Teodósio; Francisco Leitão; Mocuba, Jeremias; Florêncio dos Santos Costa, Eudriano; Teodosio, Maria; Leitão, Francisco

Monitoring the ichthyofauna is crucial to detect changes in aquatic communities for fisheries management and conservation. This study aimed to identify the most effective gear for ichthyofauna studies in the estuary. Thus, the performance of the beach seine (active gear) and chicocota (fixed gear), common fishing gears used by artisanal fishers in the Bons Sinais estuary (BSE), were used to characterise fish assemblage structure. Monthly surveys were conducted at two fixed sample points of the BSE to assess the composition of the fish assemblage. The analysis revealed statistical differences in abundance, biomass, and the presence/absence of different species between gears regardless sampling months. At ecological level, differences among gears were explained by different modus operandi, technological features and also different sampling habitats where gears operate; beach seine is catching bottom-bound and littoral fish while Chicocota is sampling the pelagic assemblage of the mid-channels. The frequency of occurrence of the 13 most abundant species differed between gears. Both gears showed little size-selectivity, with the mean total length and mean body height of these species statistically differing between gears. A total of 92 fish species were identified. No statistical differences were observed among gears for species richness, diversity and evenness. Both fishing gears captured several local socio-economically important species in the BSE. In particular, 13 of the most important species accounted for more than 54% and 60% of the total abundance and biomass in beach seine and chicocota, respectively. The complementary use of fixed and active fishing gears for studying fish community structure in estuaries is recommended. This multi-gear sampling approach enhances the capacity to detect changes in fish communities and provides valuable data for fisheries management and conservation efforts.

2024-12Journal article

Open Access