This work updates the characterization of winter fish communities in salt marsh areas of Guadiana... more This work updates the characterization of winter fish communities in salt marsh areas of Guadiana estuary (SE-Portugal) and discusses the potential risks of habitat dominance by a non-indigenous species (NIS). To this effect, six field campaigns were carried out during winter season targeting the collection of fish species. Individuals from seven different families (marine and estuarine) were collected although the community was dominated by two estuarine species – the native Pomatoschistus sp. (goby) and the NIS Fundulus heteroclitus (mummichog). Goby controlled the majority of salt marsh habitats, except one specific, marsh pool, where extreme environmental conditions were registered, namely high temperature and salinity. Such conditions may have boosted the intrusion of mummichog in this area. This species is well adapted to a wide range of abiotic factors enabling them to colonize habitats where no predators inhabit. Impacts of mummichog intrusion in the Guadiana sal...
Global change is and will continue impacting biodiversity, as many studies have already documente... more Global change is and will continue impacting biodiversity, as many studies have already documented. Rising atmospheric CO2 is alleviated by oceanic uptake, since atmosphere and surface ocean exchange CO2 , but it also modifies the ocean carbonate system towards decreased carbonate ion concentrations and a corresponding decline in seawater pH. This process is known as ocean acidification (OA) and has a direct effect on plankton, namely calcifying organisms, such as coccolithophores, foraminifers, corals, molluscs and crustaceans, with consequences for the entire marine ecosystem (see review by Reibesell and Tortell 2011).info:eu-repo/semantics/publishedVersio
The Sense Acuity and Behavioral (SAAB) Hypothesis proposes that the swimming capabilities and sen... more The Sense Acuity and Behavioral (SAAB) Hypothesis proposes that the swimming capabilities and sensorial acuity of temperate fish larvae allows them to find and swim towards coastal nursery areas, which are crucial for their recruitment. To gather further evidence to support this theory, it is necessary to understand how horizontal swimming capability varies along fish larvae ontogeny. Therefore, we studied the swimming capability of white seabream Diplodus sargus (Linnaeus, 1758) larvae along ontogeny, and their relationship with physiological condition. Thus, critical swimming speed (Ucrit) and the distance swam (km) during endurance tests were determined for fish larvae from 15 to 55 days post-hatching (DPH), and their physiological condition (RNA, DNA and protein contents) was assessed. The critical swimming speed of white seabream larvae increased along ontogeny from 1.1 cm s−1 (15 DPH) to 23 cm s−1 (50 and 55 DPH), and the distance swam by larvae in the endurance experiments in...
The rivers of São Tomé Island are colonized by Sicydium bustamantei (Greeff 1882), an amphidromou... more The 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 micr...
Climate change and the overall increase of seawater temperature is causing a poleward shift in sp... more Climate change and the overall increase of seawater temperature is causing a poleward shift in species distribution, which includes a phenomenon described as tropicalization of temperate regions. This work aims at reporting the first records of four species off the southwestern Iberian Peninsula, namely oceanic puffer Lagocephalus lagocephalus Linnaeus, 1758, Madeira rockfish Scorpaena maderensis Valenciennes, 1833, ornate wrasse Thalassoma pavo Linnaeus, 1758, and bearded fireworm Hermodice carunculata Pallas, 1766. These last three species, along with other occurrences of aquatic fauna and flora along the Portuguese coast, reveal an ongoing process of poleward expansion of several species for which a comprehensive survey along the entire Iberian Peninsula is urgent. The putative origins of these subtropical and tropical species off continental Portugal are discussed, as well as the urgent need of public awareness due to potential health risks resulting from the toxicity of two of ...
Estimates of copepod secondary production are of great importance to infer the global organic mat... more Estimates of copepod secondary production are of great importance to infer the global organic matter fluxes in aquatic ecosystems and species-specific responses of zooplankton to hydrologic variability. However, there is still no routine method to determine copepods secondary production in order to eliminate time consuming experimental analyses. Therefore, we determined whether there is a correlation between Egg Production Rates (EPR) and RNA:DNA ratios of Acartia species, by measuring their seasonal and spatial variability and the influence of environmental factors for Acartia sp. collected in the Guadiana river estuary. EPR of Acartia tonsa was positively related with chlorophyll a concentration, freshwater inflow and biomass of dinoflagellates, while Acartia clausi was only related to dinoflagellates. Dinoflagellates seem to be the optimal food item influencing the reproduction of both Acartia species in the studied area. The biochemical index RNA:DNA was positively related to EPR, indicating that it is a good proxy of copepod production and a promising method to use in the future to estimate secondary production.
The feeding ecology of Blackfordia virginica was evaluated concurrently with their ecophysiologic... more The feeding ecology of Blackfordia virginica was evaluated concurrently with their ecophysiological condition in a temperate estuary. The diet of B. virginica is composed not only of metazooplankton, as commonly observed for other jellyfish species, but also of phytoplankton, ciliates and detritus. This feeding behavior might explain their good nutritional condition and sustainable growth during bloom peaks, when zooplankton abundance has already decreased significantly.
This work updates the characterization of winter fish communities in salt marsh areas of Guadiana... more This work updates the characterization of winter fish communities in salt marsh areas of Guadiana estuary (SE-Portugal) and discusses the potential risks of habitat dominance by a non-indigenous species (NIS). To this effect, six field campaigns were carried out during winter season targeting the collection of fish species. Individuals from seven different families (marine and estuarine) were collected although the community was dominated by two estuarine species – the native Pomatoschistus sp. (goby) and the NIS Fundulus heteroclitus (mummichog). Goby controlled the majority of salt marsh habitats, except one specific, marsh pool, where extreme environmental conditions were registered, namely high temperature and salinity. Such conditions may have boosted the intrusion of mummichog in this area. This species is well adapted to a wide range of abiotic factors enabling them to colonize habitats where no predators inhabit. Impacts of mummichog intrusion in the Guadiana sal...
Global change is and will continue impacting biodiversity, as many studies have already documente... more Global change is and will continue impacting biodiversity, as many studies have already documented. Rising atmospheric CO2 is alleviated by oceanic uptake, since atmosphere and surface ocean exchange CO2 , but it also modifies the ocean carbonate system towards decreased carbonate ion concentrations and a corresponding decline in seawater pH. This process is known as ocean acidification (OA) and has a direct effect on plankton, namely calcifying organisms, such as coccolithophores, foraminifers, corals, molluscs and crustaceans, with consequences for the entire marine ecosystem (see review by Reibesell and Tortell 2011).info:eu-repo/semantics/publishedVersio
The Sense Acuity and Behavioral (SAAB) Hypothesis proposes that the swimming capabilities and sen... more The Sense Acuity and Behavioral (SAAB) Hypothesis proposes that the swimming capabilities and sensorial acuity of temperate fish larvae allows them to find and swim towards coastal nursery areas, which are crucial for their recruitment. To gather further evidence to support this theory, it is necessary to understand how horizontal swimming capability varies along fish larvae ontogeny. Therefore, we studied the swimming capability of white seabream Diplodus sargus (Linnaeus, 1758) larvae along ontogeny, and their relationship with physiological condition. Thus, critical swimming speed (Ucrit) and the distance swam (km) during endurance tests were determined for fish larvae from 15 to 55 days post-hatching (DPH), and their physiological condition (RNA, DNA and protein contents) was assessed. The critical swimming speed of white seabream larvae increased along ontogeny from 1.1 cm s−1 (15 DPH) to 23 cm s−1 (50 and 55 DPH), and the distance swam by larvae in the endurance experiments in...
The rivers of São Tomé Island are colonized by Sicydium bustamantei (Greeff 1882), an amphidromou... more The 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 micr...
Climate change and the overall increase of seawater temperature is causing a poleward shift in sp... more Climate change and the overall increase of seawater temperature is causing a poleward shift in species distribution, which includes a phenomenon described as tropicalization of temperate regions. This work aims at reporting the first records of four species off the southwestern Iberian Peninsula, namely oceanic puffer Lagocephalus lagocephalus Linnaeus, 1758, Madeira rockfish Scorpaena maderensis Valenciennes, 1833, ornate wrasse Thalassoma pavo Linnaeus, 1758, and bearded fireworm Hermodice carunculata Pallas, 1766. These last three species, along with other occurrences of aquatic fauna and flora along the Portuguese coast, reveal an ongoing process of poleward expansion of several species for which a comprehensive survey along the entire Iberian Peninsula is urgent. The putative origins of these subtropical and tropical species off continental Portugal are discussed, as well as the urgent need of public awareness due to potential health risks resulting from the toxicity of two of ...
Estimates of copepod secondary production are of great importance to infer the global organic mat... more Estimates of copepod secondary production are of great importance to infer the global organic matter fluxes in aquatic ecosystems and species-specific responses of zooplankton to hydrologic variability. However, there is still no routine method to determine copepods secondary production in order to eliminate time consuming experimental analyses. Therefore, we determined whether there is a correlation between Egg Production Rates (EPR) and RNA:DNA ratios of Acartia species, by measuring their seasonal and spatial variability and the influence of environmental factors for Acartia sp. collected in the Guadiana river estuary. EPR of Acartia tonsa was positively related with chlorophyll a concentration, freshwater inflow and biomass of dinoflagellates, while Acartia clausi was only related to dinoflagellates. Dinoflagellates seem to be the optimal food item influencing the reproduction of both Acartia species in the studied area. The biochemical index RNA:DNA was positively related to EPR, indicating that it is a good proxy of copepod production and a promising method to use in the future to estimate secondary production.
The feeding ecology of Blackfordia virginica was evaluated concurrently with their ecophysiologic... more The feeding ecology of Blackfordia virginica was evaluated concurrently with their ecophysiological condition in a temperate estuary. The diet of B. virginica is composed not only of metazooplankton, as commonly observed for other jellyfish species, but also of phytoplankton, ciliates and detritus. This feeding behavior might explain their good nutritional condition and sustainable growth during bloom peaks, when zooplankton abundance has already decreased significantly.
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