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- Age and growth of megrim, Lepidorhombus boscii, Risso of the portuguese continental coastPublication . Castilho, Rita; Dinis, Maria Teresa; Erzini, KarimThe first study of age and growth of four-spotted scaldfish, more commonly known as megrim (Lepidorhombus boscii, Risso), an important (by catch ) species of the Portuguese trawl fishery from the Atlantic coast is presented. The analysis was based on data obtained from a total of 609 specimens sampled between 1985 and 1986. Otoliths were used for age determination. The Von Bertalanf~, growth parameters were estimated using the non-linear fitting method: Lt (females)=440[ 1 -e -°-14(t+ 1.32) ] and Lt= 375 [ 1 -e -°~4(t+ 1.93) ] for males. L~ and to values are significantly different. The megrim grows allometrically (slope of length-weight regressions > 3 ). Females live longer and gain weight at a faster rate than males. Differences in growth between sexes become more apparent from the second year onwards.
- Green and hawksbill sea turtles of Eastern Atlantic: new insights into a globally important rookery in the Gulf of GuineaPublication . Ferreira-Airaud, Betania; Vieira, Sara; Branco, Maria; Pina, Antunes; Soares, Venceslau; Tiwari, Manjula; Witt, Matthew; Castilho, Rita; Teodosio, Maria; Hawkes, Lucy A.Sea turtles are critical components of marine ecosystems, and their conservation is important for Ocean Governance and Global Planet Health. However, there is limited knowledge of their ecology in the Gulf of Guinea. To fill this knowledge gap, this study presents the first integrative assessment of green and hawksbill turtles in the region, combining nesting surveys over 9 years and telemetry data, to offer insights into these population dynamics, and behaviours, including nesting preferences, morphological and reproductive parameters, diving patterns and inter-nesting core-use areas. Both green and hawksbill turtles are likely making a recovery on Sao Tome, potentially driven by sustained conservation efforts. There are preliminary indications of recovery, but we interpret this cautiously. Coupled with satellite tracking, this study estimated that 482 to 736 green turtles and 135 to 217 hawksbills nest on the beaches of Sao Tome. Their movements overlap significantly with a proposed Marine Protected Area (MPA), which suggests they may be well placed for conservation if managed appropriately. However, the presence of artisanal fisheries and emerging threats, such as sand mining and unregulated tourism, highlight the urgent need for robust management strategies that align global conservation objectives with local socioeconomic realities. This study significantly enhances our understanding of the ecology and conservation needs of the green and hawksbill turtles in the Gulf of Guinea. The insights gleaned here can contribute to the development of tailored conservation strategies that benefit these populations and the ecosystem services upon which they depend. This study presents a comprehensive assessment of green and hawksbill sea turtles in the Gulf of Guinea, combining 9 years of nesting area surveys with telemetry data. Our findings reveal promising signs of recovery for green and hawksbill turtles, driven by conservation efforts. Our research underscores the importance of effective conservation strategies, especially in the face of emerging threats, to protect these vital marine species and their ecosystems in the Eastern Atlantic.image
- Hidden diversity of the olive ridley sea turtle (Lepidochelys olivacea) from Angola, West AfricaPublication . Cunha, Regina L.; Costa, Adjany; Godinho, Filipa; Santos, Carmen; Castilho, RitaThe olive ridley sea turtle (Lepidochelys olivacea) occupies a wide range within the tropical and subtropical areas of the Pacific, Indian, and Southern Atlantic Oceans. Although occurring in large numbers, the IUCN status for this species is "vulnerable" due to existing threats in their nesting sites. We report the first genetic data on L. olivacea from Palmeirinhas-Onca beach, Angola, West Africa. Genetic diversity based on a 400 bp-fragment of the mitochondrial control region of 39 individuals indicated low nucleotide and haplotype diversities compared to other Atlantic populations. We detected a new haplotype present in two individuals from Angola, while the remaining specimens shared a haplotype that is distributed in both sides of the Atlantic and in the Mediterranean, suggesting connectivity between these populations. The baseline data we are generating have a broader significance for characterizing intraspecific biodiversity in the olive ridley sea turtle, which is vital for developing effective conservation policies.
- Green and Hawksbill sea turtles of Eastern Atlantic: new insights into a globally important rookery in the Gulf of GuineaPublication . Ferreira-Airaud, Betânia; Vieira, Sara; Branco, Maria; Pina, Antunes; Soares, Venceslau; Tiwari, Manjula; Witt, Matthew; Castilho, Rita; Teodosio, Maria; Hawkes, Lucy A.Sea turtles are critical components of marine ecosystems, and their conservation is important for Ocean Governance and Global Planet Health. However, there is limited knowledge of their ecology in the Gulf of Guinea. To fill this knowledge gap, this study presents the first integrative assessment of green and hawksbill turtles in the region, combining nesting surveys over 9 years and telemetry data, to offer insights into these population dynamics, and behaviours, including nesting preferences, morphological and reproductive parameters, diving patterns and inter-nesting core-use areas. Both green and hawksbill turtles are likely making a recovery on São Tomé, potentially driven by sustained conservation efforts. There are preliminary indications of recovery, but we interpret this cautiously. Coupled with satellite tracking, this study estimated that 482 to 736 green turtles and 135 to 217 hawksbills nest on the beaches of São Tomé. Their movements overlap significantly with a proposed Marine Protected Area (MPA), which suggests they may be well placed for conservation if managed appropriately. However, the presence of artisanal fisheries and emerging threats, such as sand mining and unregulated tourism, highlight the urgent need for robust management strategies that align global conservation objectives with local socioeconomic realities. This study significantly enhances our understanding of the ecology and conservation needs of the green and hawksbill turtles in the Gulf of Guinea. The insights gleaned here can contribute to the development of tailored conservation strategies that benefit these populations and the ecosystem services upon which they depend.