Mistrust between scientists and non-scientist stakeholders is a key challenge in fishery manageme... more Mistrust between scientists and non-scientist stakeholders is a key challenge in fishery management. The support of management with complex models is difficult, as these models cannot easily communicate their results to end users, resulting in a lack of confidence. As an example, the complex life cycle of the European eel raises problems of coordination and discussion among the multiple actors involved in the species’ management. The GEREM model has been proposed as a tool for estimating recruitment, but its complexity, which is essential for addressing the characteristics of the species, makes it difficult to understand and accept by all stakeholders. In the context of the SUDOANG project, we proposed a co-parametrisation of this assessment model to tackle this mistrust. Through the use of various questionnaires, stakeholders were involved in two important choices for the model (zone definition and prior construction). Regular workshops and presentations were organised to explain t...
Long-term time-series datasets are key for assessing the population dynamics of fish species with... more Long-term time-series datasets are key for assessing the population dynamics of fish species with economic interest. This study examines two 100-year datasets for sea lamprey Petromyzon marinus and allis shad Alosa alosa from the Minho River. This basin on the Iberian Peninsula is home to one of the largest populations at the southern distribution limit of these critically endangered anadromous fish species. Besides assessing the importance of the environmental drivers of fish capture data (temperature, salinity, upwelling, precipitation, and climatic oscillation), this study also assesses how dam construction affected these populations using intervention analysis—A statistical tool to detect significant breakpoints in time series data. Results showed contrasting trends between sea lamprey and allis shad, with the number of captured fish from the first progressively improving from 1914 to 2017, and the latter recording a significant decline over time. Although no significant correla...
Seasonal variation of the subtidal macrobenthic community in the lower Lima estuary was investiga... more Seasonal variation of the subtidal macrobenthic community in the lower Lima estuary was investigated at twelve sites. Univariate and multivariate analyses were used to establish patterns in species distribution, abundance, and biomass; and to determine the influence of site and season on the subtidal macrobenthic community. A total of 101 macrobenthic taxa were identified and values of diversity were generally low indicating a high degree of dominance of few species. Average abundance and biomass per site ranged from 46.7 to 8060 ind. m -2 and 0.56 to 28.96 g AFDW m -2 , respectively. Abra alba was most abundant and had the highest biomass. Multivariate analysis revealed four distinct groups. Each group was represented by a specific species composition and characterised by different environmental conditions, in particular, the sediment characteristics and salinity. Abundance/biomass comparison (ABC) indicated that the lower part of the estuary is under environmental stress and is do...
Fluxes of organic matter (OM) from terrestrial ecosystems subsidize stream food webs, which suppo... more Fluxes of organic matter (OM) from terrestrial ecosystems subsidize stream food webs, which support the production of ecologically and economically important species such as the sea lamprey Petromyzon marinus. Debris have been previously observed in the gut contents of sea lamprey ammocoetes, but their origin and/or the nutritional sources assimilated are still poorly known. We used carbon (δ13C: 13C/12C) and nitrogen (δ15N: 15N/14N) stable isotopes to identify the main OM sources supporting the production of ammocoetes in a tributary of the Minho River (NW-Iberian Peninsula). Ammocoetes δ13C and C:N values increased with length. Smaller individuals likely assimilated more 13C- depleted sources such as fresh or decaying plant material. The increase in the C:N values with length suggests that ammocoetes accumulate lipids to support their metamorphosis and recruitment into an adult animal. Ammocoetes smaller than 30 mm presented an unusual variability for both δ15N and δ13C values, with values varying between 3.2‰ and 17.8‰ for δ15N and between − 38‰ and − 25.5‰ for δ13C in the same sampling site. This suggests that factors such as organic pollution inputs or time to the first feeding may have contributed to the observed variability. Detritus from the adjacent riparian vegetation was identified as the main food source assimilated by sea lamprey ammocoetes. The stable isotope mixing model (95% CI) indicates that the relative contribution of decaying riparian plants detritus varied between 38–59% and 55–73% at the end of the summer decreasing towards the end of the winter (2–34%). The relative contribution of other terrestrial-derived OM (i.e. fresh riparian detritus and particulate OM with terrestrial origin) was only relevant (> 40%) at the end of the winter. This study shows that there is a strong connectivity between the stream food web and the adjacent riparian ecosystem, and that protection of both riparian and catchment forest cover are essential to preserve terrestrial-aquatic linkages which can support the development of sea lamprey ammocoetes.
The epibenthic community of the Minho Estuary was studied during the summer of 2006. Diversity wa... more The epibenthic community of the Minho Estuary was studied during the summer of 2006. Diversity was generally low and a total of 14 fish and five crustacean taxa were identified. Multivariate analysis revealed two site clusters (A and B). Water conductivity and percentage of fine sand were the abiotic variables that most contributed to the spatial distinction between clusters. The species contributing the most to the average similarity within Cluster A were Crangon crangon and Pomatoschistus microps, while in Cluster B was Atyaephyra ...
... 5 de Outubro, 8700-305 Olhão, Portugal. 5 Aquamuseu do Rio Minho – Parque do Castelinho, 4920... more ... 5 de Outubro, 8700-305 Olhão, Portugal. 5 Aquamuseu do Rio Minho – Parque do Castelinho, 4920-290 Vila Nova de Cerveira, Portugal. *ronaldo.sousa@ciimar.up.pt 1. INTRODUCTION ... (2000), with form A of Siripattrawan et al. (2000) and Lee et al. (2005) (Fig. 5). ...
Estuarine, Coastal and Shelf Science, Nov 10, 2008
The Asian clam Corbicula fluminea (Müller, 1774) is a major component of the River Minho estuary,... more The Asian clam Corbicula fluminea (Müller, 1774) is a major component of the River Minho estuary, almost completely dominating the benthic biomass. As part of a major study into the ecology of C. fluminea, benthic samples were collected monthly from January 2005 to August 2006. These data were then used to estimate the abundance, biomass, growth, and growth and elimination production of this non-indigenous invasive species. Corbicula fluminea growth was continuous throughout its life span. The annual 2005 growth ...
Crustaceans (Arthropoda) are a diverse and abundant group with chitinous exoskeleton, living on c... more Crustaceans (Arthropoda) are a diverse and abundant group with chitinous exoskeleton, living on coastal/estuarine environments, at community invertebrate fauna. A survey on the species of some crustacean groups found on the Minho River estuary (international section) in the Iberian Peninsula, is presented with specimens collected through glass eel fishing bycatch, grab sampler, trammel net, beam trawl and fyke net sampling methods. A total of 98 specimens were examined belonging to 7 orders, 21 genera and 23 species (17 new records from Minho River, including one for Portugal). Brief diagnosis, ecological notes, species distributions and figures are provided intending to present taxonomic support on future projects in this region.
Mistrust between scientists and non-scientist stakeholders is a key challenge in fishery manageme... more Mistrust between scientists and non-scientist stakeholders is a key challenge in fishery management. The support of management with complex models is difficult, as these models cannot easily communicate their results to end users, resulting in a lack of confidence. As an example, the complex life cycle of the European eel raises problems of coordination and discussion among the multiple actors involved in the species’ management. The GEREM model has been proposed as a tool for estimating recruitment, but its complexity, which is essential for addressing the characteristics of the species, makes it difficult to understand and accept by all stakeholders. In the context of the SUDOANG project, we proposed a co-parametrisation of this assessment model to tackle this mistrust. Through the use of various questionnaires, stakeholders were involved in two important choices for the model (zone definition and prior construction). Regular workshops and presentations were organised to explain t...
Long-term time-series datasets are key for assessing the population dynamics of fish species with... more Long-term time-series datasets are key for assessing the population dynamics of fish species with economic interest. This study examines two 100-year datasets for sea lamprey Petromyzon marinus and allis shad Alosa alosa from the Minho River. This basin on the Iberian Peninsula is home to one of the largest populations at the southern distribution limit of these critically endangered anadromous fish species. Besides assessing the importance of the environmental drivers of fish capture data (temperature, salinity, upwelling, precipitation, and climatic oscillation), this study also assesses how dam construction affected these populations using intervention analysis—A statistical tool to detect significant breakpoints in time series data. Results showed contrasting trends between sea lamprey and allis shad, with the number of captured fish from the first progressively improving from 1914 to 2017, and the latter recording a significant decline over time. Although no significant correla...
Seasonal variation of the subtidal macrobenthic community in the lower Lima estuary was investiga... more Seasonal variation of the subtidal macrobenthic community in the lower Lima estuary was investigated at twelve sites. Univariate and multivariate analyses were used to establish patterns in species distribution, abundance, and biomass; and to determine the influence of site and season on the subtidal macrobenthic community. A total of 101 macrobenthic taxa were identified and values of diversity were generally low indicating a high degree of dominance of few species. Average abundance and biomass per site ranged from 46.7 to 8060 ind. m -2 and 0.56 to 28.96 g AFDW m -2 , respectively. Abra alba was most abundant and had the highest biomass. Multivariate analysis revealed four distinct groups. Each group was represented by a specific species composition and characterised by different environmental conditions, in particular, the sediment characteristics and salinity. Abundance/biomass comparison (ABC) indicated that the lower part of the estuary is under environmental stress and is do...
Fluxes of organic matter (OM) from terrestrial ecosystems subsidize stream food webs, which suppo... more Fluxes of organic matter (OM) from terrestrial ecosystems subsidize stream food webs, which support the production of ecologically and economically important species such as the sea lamprey Petromyzon marinus. Debris have been previously observed in the gut contents of sea lamprey ammocoetes, but their origin and/or the nutritional sources assimilated are still poorly known. We used carbon (δ13C: 13C/12C) and nitrogen (δ15N: 15N/14N) stable isotopes to identify the main OM sources supporting the production of ammocoetes in a tributary of the Minho River (NW-Iberian Peninsula). Ammocoetes δ13C and C:N values increased with length. Smaller individuals likely assimilated more 13C- depleted sources such as fresh or decaying plant material. The increase in the C:N values with length suggests that ammocoetes accumulate lipids to support their metamorphosis and recruitment into an adult animal. Ammocoetes smaller than 30 mm presented an unusual variability for both δ15N and δ13C values, with values varying between 3.2‰ and 17.8‰ for δ15N and between − 38‰ and − 25.5‰ for δ13C in the same sampling site. This suggests that factors such as organic pollution inputs or time to the first feeding may have contributed to the observed variability. Detritus from the adjacent riparian vegetation was identified as the main food source assimilated by sea lamprey ammocoetes. The stable isotope mixing model (95% CI) indicates that the relative contribution of decaying riparian plants detritus varied between 38–59% and 55–73% at the end of the summer decreasing towards the end of the winter (2–34%). The relative contribution of other terrestrial-derived OM (i.e. fresh riparian detritus and particulate OM with terrestrial origin) was only relevant (> 40%) at the end of the winter. This study shows that there is a strong connectivity between the stream food web and the adjacent riparian ecosystem, and that protection of both riparian and catchment forest cover are essential to preserve terrestrial-aquatic linkages which can support the development of sea lamprey ammocoetes.
The epibenthic community of the Minho Estuary was studied during the summer of 2006. Diversity wa... more The epibenthic community of the Minho Estuary was studied during the summer of 2006. Diversity was generally low and a total of 14 fish and five crustacean taxa were identified. Multivariate analysis revealed two site clusters (A and B). Water conductivity and percentage of fine sand were the abiotic variables that most contributed to the spatial distinction between clusters. The species contributing the most to the average similarity within Cluster A were Crangon crangon and Pomatoschistus microps, while in Cluster B was Atyaephyra ...
... 5 de Outubro, 8700-305 Olhão, Portugal. 5 Aquamuseu do Rio Minho – Parque do Castelinho, 4920... more ... 5 de Outubro, 8700-305 Olhão, Portugal. 5 Aquamuseu do Rio Minho – Parque do Castelinho, 4920-290 Vila Nova de Cerveira, Portugal. *ronaldo.sousa@ciimar.up.pt 1. INTRODUCTION ... (2000), with form A of Siripattrawan et al. (2000) and Lee et al. (2005) (Fig. 5). ...
Estuarine, Coastal and Shelf Science, Nov 10, 2008
The Asian clam Corbicula fluminea (Müller, 1774) is a major component of the River Minho estuary,... more The Asian clam Corbicula fluminea (Müller, 1774) is a major component of the River Minho estuary, almost completely dominating the benthic biomass. As part of a major study into the ecology of C. fluminea, benthic samples were collected monthly from January 2005 to August 2006. These data were then used to estimate the abundance, biomass, growth, and growth and elimination production of this non-indigenous invasive species. Corbicula fluminea growth was continuous throughout its life span. The annual 2005 growth ...
Crustaceans (Arthropoda) are a diverse and abundant group with chitinous exoskeleton, living on c... more Crustaceans (Arthropoda) are a diverse and abundant group with chitinous exoskeleton, living on coastal/estuarine environments, at community invertebrate fauna. A survey on the species of some crustacean groups found on the Minho River estuary (international section) in the Iberian Peninsula, is presented with specimens collected through glass eel fishing bycatch, grab sampler, trammel net, beam trawl and fyke net sampling methods. A total of 98 specimens were examined belonging to 7 orders, 21 genera and 23 species (17 new records from Minho River, including one for Portugal). Brief diagnosis, ecological notes, species distributions and figures are provided intending to present taxonomic support on future projects in this region.
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