Browsing by Author "Branco, Maria"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- Feeding ecology of sicydium bustamantei (Greeff 1884, Gobiidae) post-larvae: the “Little Fish” of São Tomé IslandPublication . Baptista, Vânia; Dias, Ester; Cruz, Joana; Branco, Maria; Vieira, Sara; Teodosio, Maria AlexandraThe rivers of São Tomé Island are colonized by Sicydium bustamantei (Greeff 1882), an amphidromous fish that spawns in those areas. After hatching, larvae drift to the ocean with the river flow. In the marine realm, the planktonic larvae develop and migrate to freshwater as post-larvae. The migrations of post-larvae support important local fisheries at the mouth of rivers in tropical volcanic islands. Amphidromous post-larvae rely on plankton as their main source of organic matter. However, the biology and ecology of S. bustamantei in the West African islands are understudied, despite its importance for local fisheries. Thus, this study aimed to start bridging this gap by studying its feeding ecology. Our objectives were to identify the main prey of S. bustamantei post-larvae, combining gut content with stable isotope analyses. The gut contents included zooplankton (Chaetognatha, Ostracoda, and unidentified crustaceans), debris from plant and/or macroalgae-derived material, and microplastics (including microfibers). The stable isotopes analysis indicated that zooplankton and macroalgae detritus were the main sources of organic matter assimilated by this species. We also demonstrated that S. bustamantei post-larvae are omnivorous and secondary consumers. These data provide pioneering information that can be used in management plans that still need to be developed.
- 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
- 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.
- Phytoplankton dynamics in southern Portuguese coastal lagoons during a discontinuous period of 40 yearsPublication . Brito, Ana; Quental, Teresa; Coutinho, Teresa; Branco, Maria; Falcão, Manuela; Newton, Alice; Icely, John; Moita, TeresaShallow coastal lagoons in southern Portugal, such as the Ria Formosa and Alvor, are considered to be highly important both ecologically and economically. Given the impact of phytoplankton in the ecosystem productivity, it is important to understand its dynamics and to consider them for the assessment of ecosystem health. All available phytoplankton data(chlorophyll a; selected species composition and abundance) within the period from 1967 to 2011 were compiled within the framework of a project to implement the Water Framework Directive. Chlorophyll a (chl a)measurements in Ria Formosa from 1967 to 1968, 1985 to 1986, 1991 to 1992, 2006 to 2008, and 2010 show similar monthly averages with some exceptions. In the 80’s the monthly averages were less than half of what was observed in the 60’s. In the 90’s, the chl a concentrations increased significantly and in the period from 2006 to 2010, chl a concentrations ranged between the values found in the 80’s. The decrease in chl a concentrations during the 80’s is likely to be associated with a peak in shellfish production. Shellfish production was recorded to have decreased from 1990 onwards. Chl concentrations in Ria de Alvor are found to vary within the same range as in Ria Formosa. However, data are limited and does not allow a detailed historical comparison. During the most important chl a peaks, the phytoplankton community was characterized by coastal species, such as Pseudo-nitzschia sp., which may be associated with upwelling events. This was found in Ria Formosa both in the 90’s and from 2000 onwards, as well as in the most recent data from Ria de Alvor. This clearly indicates the influence of the coastal dynamics in these lagoons. High chl outside the lagoon confirmed the influence of coastal waters. In addition, high chl concentrations were also observed at inner parts of the lagoon but not outside, suggesting the existence of an interior maximum. The community was mainly characterized by the existence of low salinity tolerant species, such as Kryptoperidinium foliaceum. Over the time intervals in this study, the 90th percentile values of chlorophyll a concentrations were 3.0 in Ria Formosa and 2.6 mg m 3 in the Ria de Alvor. In a five-fold classification of ecological quality from High to Bad, we propose chlorophyll a concentrations of 5.3 mg m 3 as a reference value, 8 mg m 3 for the boundary High/Good, and 12 mg m 3 for the boundary Good/Moderate. According to this, all water bodies were considered as in High status.