Latin American Journal of Aquatic Research, Dec 1, 2010
The effect of the Orion shipwreck on fish assemblage distribution near the reef was studied to th... more The effect of the Orion shipwreck on fish assemblage distribution near the reef was studied to the northeast of Rio de Janeiro with six different fishing gears: gillnets, mid-water longlines, circular traps, rectangular traps, vertical longlines, and bottom trawling. The study consisted of a pre-monitoring survey four months before the shipwreck in the area (A) and in two control areas (B and C). After 36 months, a total of 56 species were caught in the Orion reef area, 49 in control area B and 59 in control area C. The similarity analysis, considering the number of fish caught during the nine surveys in the three study areas, clustered the pre-monitoring and first post-settlement surveys of the three sites. This occurred due to the low number of fish captured and the dominance of Trichiurus lepturus and Lagocephalus laevigatus. These results differed from all the other studies in the three areas due to the co-dominance of Ctenosciaena gracilicirrhus and Stephanolepis hispidus. Such spatial similarity shows the low influence of the Orion reef in the area after three years. Biomass values were 15% higher in the Orion reef area than in the control areas, representing an increase of up to 1.2 times in wet weight. The increment of fish communities is still insufficient for proposing sustainable fishery activity in the shipwreck area. The monitoring time (32 months) after the sinking of the Orion may be considered too short to assure that the wreckage had reached its maturity as an artificial reef, either as a fish attractor or producer.
Patterns of community structure in the marine environment are strongly influenced by population r... more Patterns of community structure in the marine environment are strongly influenced by population relationships to biotic and physical gradients. The aim of this work is to explore the relationships of tropical rocky reef fish assemblages to wave exposure and benthic coverage in a gradient of distance from the coast. The study was conducted on the Guarapari Islands, southeastern Brazilian coast. Fish were sampled by underwater visual census (166 transects) and benthic cover was estimated with quadrats (223 replicates). Two main kinds of habitats were found to be derived from the close interrelation between exposure and benthic coverage: (1) exposed areas subjected to major hydrodynamic forcing, and (2) sheltered or moderately exposed areas. The first group is associated with mid-water schooling species like planktivorous labrids and Chromis, piscivorous Caranx, as well as gregarious omnivores like Abudefduf and Diplodus. In terms of benthic composition, macroalgae and encrusting calcareous algae prevail in this highenergy habitat. The second group is characterized by site-attached and reef associated species like territorial pomacentrids, invertebrate feeders such as Halichoeres poeyi and Chaetodon striatus, and small cryptobenthic fishes (e.g. blenniids and labrisomids). Turf algae, zoanthids and massive corals dominate this environment. Environmental plasticity is also common with some genera showing high abundances in all habitats (e.g. Holocentrus, Haemulon, Acanthurus). Examples of the coupling of food availability and fish abundance were found. Planktivores, territorial herbivores, macroalgae browsers and spongivores were positively related with the abundance of their preferred food items along the exposure gradient. Within-family analyses of Pomacentridae and Labridae showed that niche partitioning is likely occurring and seems to be mediated by swimming 'ability' and associated feeding performance.
Recifes artificiais são estruturas introduzidas pelo homem no ambiente marinho e contribuem para ... more Recifes artificiais são estruturas introduzidas pelo homem no ambiente marinho e contribuem para modificações locais no hidrodinamismo, granulometria e disponibilidade de nutrientes do sedimento. Estudos direcionados são importantes para se avaliar o quanto tais estruturas experimentais interferem na composição e dinâmica de comunidades macrobênticas. A área do presente estudo está localizada entre a foz dos rios Paraíba do Sul e Itabapoana. O complexo de recifes artificiais composto por 36 reefballs situa-se a cerca de três milhas da praia de Manguinhos (21°29'S, 41°00'W), em São Francisco de Itabapoana, costa norte do Estado do Rio de Janeiro, a cerca de 9 m de profundidade. O principal objetivo foi caracterizar a comunidade macrobentônica com e sem influência do recife artificial. Amostras de sedimento foram coletadas com um corer de 15 cm no recife artificial (RA) e em duas áreas controle, norte (CN) e sul (CS), a 500 m de distância do complexo recifal. Uma parte foi separada para análise granulométrica e a restante fixada com formol a 10%. No laboratório, as amostras foram lavadas, peneiradas em malha de 500 µm para separação da macrofauna, fixadas em álcool 70%, triadas e identificadas. O número total e médio de táxons foi superior no RA (N total = 66, N médio = 13) comparado ao CN (N total = 21 táxons e N médio = 4) e CS (N total = 17 táxons e N médio = 3). O número total de táxons por grande grupo nas três áreas de estudo (RA, CN e CS) revelou o predomínio de Polychaeta (24, 11, 8 respectivamente), seguido por moluscos (16, 2 e 4, respectivamente) e crustáceos (14, 3 e 1, respectivamente). O número total e médio de indivíduos nos RAs (N total = 181, N médio = 20) foram superiores às áreas controles (CN: N total = 37, N médio = 4; CS: N total = 27 e N médio = 3). Da mesma forma, a diversidade média de Shannon apresentou-se superior nos RAs (H' médio = 2,27) comparada ao CN (H' médio = 0,84) e CS (H' médio = 0,69). Acredita-se que os valores superiores no complexo recifal referentes à estrutura da comunidade como riqueza e diversidade possam estar relacionados à maior heterogeneidade do sedimento registrada próxima dos RAs, com concentrações mais elevadas de cascalho e lama, resultado da maior abundância de crustáceos (N = 44) e moluscos (N = 40) nos recifes comparada aos controles norte (N = 9; N = 3) e sul (N = 1; N = 6), respectivamente. Já nos controles norte e sul, o sedimento foi mais homogêneo devido ao predomínio de lama.
To investigate how variations in the smallscale distance between patchy reef modules affect the s... more To investigate how variations in the smallscale distance between patchy reef modules affect the structure and composition of the associated ichthyofauna, concrete reefballs were arranged in three distance configurations, 0.5, 5 and 15 m, at 9 m depth off the northern Rio de Janeiro coast. The ichthyofauna was sampled in the dry and rainy seasons using gillnets, and the composition, richness, diversity, abundance and biomass per distance unit were recorded. The availability of potential macrobenthic prey was evaluated using a stainless steel corer for each inter-module distance, and the results correlated with the stomach contents of the captured ichthyofauna. Community descriptors did not significantly change with treatments of reef distance. A canonical correspondence analysis revealed similar fish composition among reef distance treatments, but increased occurrence of exclusive species and habitatdependent fish with increased distances among reef modules. Non-metric multidimensional scaling showed different composition of fish populations between sampling periods, with a predominance of Sciaenidae in the dry season and Ariidae and Carcharhinidae on the rainy season. The adjacent infauna was not directly related to the ichthyofauna but to the benthic prey, which were possibly using the structure interstices, and small fish. Significant effects of seasonal freshwater and sediment loads from large regional coastal rivers may override the effects of reef configuration, especially during rainy seasons with higher inflow. As the shorter reef distance exhibited generally the same richness and abundance compared with larger and more distant reefs, a patchy design with \5.0 m distances is thus recommended for the distribution of artificial reefs to increase fish biodiversity in coastal environments with homogeneous substrate and seasonally influenced by freshwater outflow and sediment from large rivers.
We present here the first results of Hg concentrations in three small shark species (Rhizoprionod... more We present here the first results of Hg concentrations in three small shark species (Rhizoprionodon lalandei, R. porosus and Mustelus higmani) from the SE Brazilian coast. Mercury concentrations in R. lalandei ranged from 21.5 to 280.0 ng.g -1 dry weight (d.w.) (average 74.6 ng.g -1 d.w.; 17.9 ng.g -1 wet weight). In R. porosus, concentrations ranged from 7.6 to 90.5 ng.g -1 d.w. (average 42.2 ng.g -1 d.w., 9.4 ng.g -1 wet weight), whereas in M. higmani, concentrations ranged from 13.0 to 162.8 ng.g -1 d.w. (average 54.9 ng.g -1 d.w., 13.4 ng.g -1 wet weight). These concentration ranges are very low compared with values reported for other large shark species of the Southwestern Atlantic Ocean. There was a significant positive correlation between Hg concentrations and individual size, suggesting that biomagnification is occurring in these animals.
ABSTRACT To investigate how variations in the volume of artificial reefs affect the structure and... more ABSTRACT To investigate how variations in the volume of artificial reefs affect the structure and composition of the transient ichthyofauna, reefball-type concrete modules were arranged at 9 m of depth along the northern coast of the state of Rio de Janeiro. The modules were arranged in three configurations, each in triplicate: (1) solitary modules (1 m3), (2) side-by-side modules (2 m3) and (3) modules forming a triangle (3 m3). The surrounding ichthyofauna were sampled in two periods of the year (dry: September 2009 and October 2010; rainy: April 2010 and April 2011) with gillnets to record the richness, species diversity, number of individuals and biomass per volume unit. The total mean values of richness, diversity, number of individuals and biomass did not differ significantly among the reef volumes. However, when these variables were analyzed per standardized volume unit, there was an increase in these variables with the increase in reef volume, considering all the transient ichthyofauna as well as the most representative families, Ariidae and Sciaenidae. A non-metric multidimensional scaling ordination analysis revealed differences in the composition of the ichthyofauna between the sampling periods, dominated by Sciaenidae (Stellifer rastrifer, Paralonchurus brasiliensis, Larimus breviceps and Cynoscion virescens) in the dry period and by Ariidae (Aspistor luniscutis) and Carcharinidae (Rhizoprionodon porosus) in the rainy period. The results suggest that the increase in module size from 1 to 3 m3 may result in slight alterations in the community descriptors, with a decrease in the relative values of richness, diversity and density per standardized volume unit. Furthermore, the effects of the seasonal flow of the Paraíba do Sul River may overlap the effects of reef configuration, mainly in the rainy period with higher flow. The implementation of several dispersed 1 m3 modules seems to be the most favorable configuration to attract transient ichthyofauna, especially Ariidae and Sciaenidae, on the northern coast of the state of Rio de Janeiro.
Journal of the Marine Biological Association of the United Kingdom, 2014
Artificial reefs (ARs) are often used to improve fishing and, consequently, the economy of a regi... more Artificial reefs (ARs) are often used to improve fishing and, consequently, the economy of a region. However, the way in which the species use the reefs may vary between fish assemblages. An assessment was made of the influence of an AR complex on the transient fish population off the northern coast of Rio de Janeiro state and, therefore, two control areas were sampled. Gillnets were used to capture individual fish in six sampling surveys. Cumulative abundance and biomass curves (ABC) were used to assess the possible effects of the reefs on the community’s functional structure. In the dry season, during which the influence of the Paraíba do Sul River is smaller, a larger richness of r-strategy species and juveniles of K-strategy species was observed in the reef area compared with the control areas, suggesting that the AR acts as a protective environment for these species. During the lower river discharge period the results indicated a potential disturbance in the functional structure of the AR fish community and, therefore, a less stable environment relative to the control areas. This ‘instability’ warrants a positive connotation, as it indicates that the artificial reefs are harbouring species that are particularly sensitive to predation, making the reef a powerful tool for maintaining these populations on the northern coast of Rio de Janeiro.
ABSTRACT Spatial variations on the macrobenthic composition and structure associated with artific... more ABSTRACT Spatial variations on the macrobenthic composition and structure associated with artificial reefs (ARs) on the south-eastern Brazil coast were related to particle size and geochemical characteristics of the sediment and to bottom currents velocity in the vicinity of ARs and two control areas (CAs). The sampling periods were related to Paraiba do Sul River (PSR) flow, highest in summer months. The sediment was more heterogeneous near the ARs, composed mainly of mud and gravel and with greater abundance of shellfish compared to the CAs predominated by mud. The influence of the artificial structures on the hydrodynamics of the site was evident with significantly lower current velocity. Macrobenthos richness, abundance and diversity varied spatially, with higher mean values near the ARs in both sampling periods, reinforcing the influence of artificial structures on the associated infauna. Significant temporal differences in the concentrations of phosphorus, nitrogen and dissolved organic carbon only on the CAs suggest that the effect of the artificial structures surpasses the environmental seasonality related to the PSR flow. The artificial modules created a more heterogeneous grain size of the sediment that contributed to the enrichment of associated macrobenthos, with higher species richness and abundance due to a higher niche availability.
Latin American Journal of Aquatic Research, Dec 1, 2010
The effect of the Orion shipwreck on fish assemblage distribution near the reef was studied to th... more The effect of the Orion shipwreck on fish assemblage distribution near the reef was studied to the northeast of Rio de Janeiro with six different fishing gears: gillnets, mid-water longlines, circular traps, rectangular traps, vertical longlines, and bottom trawling. The study consisted of a pre-monitoring survey four months before the shipwreck in the area (A) and in two control areas (B and C). After 36 months, a total of 56 species were caught in the Orion reef area, 49 in control area B and 59 in control area C. The similarity analysis, considering the number of fish caught during the nine surveys in the three study areas, clustered the pre-monitoring and first post-settlement surveys of the three sites. This occurred due to the low number of fish captured and the dominance of Trichiurus lepturus and Lagocephalus laevigatus. These results differed from all the other studies in the three areas due to the co-dominance of Ctenosciaena gracilicirrhus and Stephanolepis hispidus. Such spatial similarity shows the low influence of the Orion reef in the area after three years. Biomass values were 15% higher in the Orion reef area than in the control areas, representing an increase of up to 1.2 times in wet weight. The increment of fish communities is still insufficient for proposing sustainable fishery activity in the shipwreck area. The monitoring time (32 months) after the sinking of the Orion may be considered too short to assure that the wreckage had reached its maturity as an artificial reef, either as a fish attractor or producer.
Patterns of community structure in the marine environment are strongly influenced by population r... more Patterns of community structure in the marine environment are strongly influenced by population relationships to biotic and physical gradients. The aim of this work is to explore the relationships of tropical rocky reef fish assemblages to wave exposure and benthic coverage in a gradient of distance from the coast. The study was conducted on the Guarapari Islands, southeastern Brazilian coast. Fish were sampled by underwater visual census (166 transects) and benthic cover was estimated with quadrats (223 replicates). Two main kinds of habitats were found to be derived from the close interrelation between exposure and benthic coverage: (1) exposed areas subjected to major hydrodynamic forcing, and (2) sheltered or moderately exposed areas. The first group is associated with mid-water schooling species like planktivorous labrids and Chromis, piscivorous Caranx, as well as gregarious omnivores like Abudefduf and Diplodus. In terms of benthic composition, macroalgae and encrusting calcareous algae prevail in this highenergy habitat. The second group is characterized by site-attached and reef associated species like territorial pomacentrids, invertebrate feeders such as Halichoeres poeyi and Chaetodon striatus, and small cryptobenthic fishes (e.g. blenniids and labrisomids). Turf algae, zoanthids and massive corals dominate this environment. Environmental plasticity is also common with some genera showing high abundances in all habitats (e.g. Holocentrus, Haemulon, Acanthurus). Examples of the coupling of food availability and fish abundance were found. Planktivores, territorial herbivores, macroalgae browsers and spongivores were positively related with the abundance of their preferred food items along the exposure gradient. Within-family analyses of Pomacentridae and Labridae showed that niche partitioning is likely occurring and seems to be mediated by swimming 'ability' and associated feeding performance.
Recifes artificiais são estruturas introduzidas pelo homem no ambiente marinho e contribuem para ... more Recifes artificiais são estruturas introduzidas pelo homem no ambiente marinho e contribuem para modificações locais no hidrodinamismo, granulometria e disponibilidade de nutrientes do sedimento. Estudos direcionados são importantes para se avaliar o quanto tais estruturas experimentais interferem na composição e dinâmica de comunidades macrobênticas. A área do presente estudo está localizada entre a foz dos rios Paraíba do Sul e Itabapoana. O complexo de recifes artificiais composto por 36 reefballs situa-se a cerca de três milhas da praia de Manguinhos (21°29'S, 41°00'W), em São Francisco de Itabapoana, costa norte do Estado do Rio de Janeiro, a cerca de 9 m de profundidade. O principal objetivo foi caracterizar a comunidade macrobentônica com e sem influência do recife artificial. Amostras de sedimento foram coletadas com um corer de 15 cm no recife artificial (RA) e em duas áreas controle, norte (CN) e sul (CS), a 500 m de distância do complexo recifal. Uma parte foi separada para análise granulométrica e a restante fixada com formol a 10%. No laboratório, as amostras foram lavadas, peneiradas em malha de 500 µm para separação da macrofauna, fixadas em álcool 70%, triadas e identificadas. O número total e médio de táxons foi superior no RA (N total = 66, N médio = 13) comparado ao CN (N total = 21 táxons e N médio = 4) e CS (N total = 17 táxons e N médio = 3). O número total de táxons por grande grupo nas três áreas de estudo (RA, CN e CS) revelou o predomínio de Polychaeta (24, 11, 8 respectivamente), seguido por moluscos (16, 2 e 4, respectivamente) e crustáceos (14, 3 e 1, respectivamente). O número total e médio de indivíduos nos RAs (N total = 181, N médio = 20) foram superiores às áreas controles (CN: N total = 37, N médio = 4; CS: N total = 27 e N médio = 3). Da mesma forma, a diversidade média de Shannon apresentou-se superior nos RAs (H' médio = 2,27) comparada ao CN (H' médio = 0,84) e CS (H' médio = 0,69). Acredita-se que os valores superiores no complexo recifal referentes à estrutura da comunidade como riqueza e diversidade possam estar relacionados à maior heterogeneidade do sedimento registrada próxima dos RAs, com concentrações mais elevadas de cascalho e lama, resultado da maior abundância de crustáceos (N = 44) e moluscos (N = 40) nos recifes comparada aos controles norte (N = 9; N = 3) e sul (N = 1; N = 6), respectivamente. Já nos controles norte e sul, o sedimento foi mais homogêneo devido ao predomínio de lama.
To investigate how variations in the smallscale distance between patchy reef modules affect the s... more To investigate how variations in the smallscale distance between patchy reef modules affect the structure and composition of the associated ichthyofauna, concrete reefballs were arranged in three distance configurations, 0.5, 5 and 15 m, at 9 m depth off the northern Rio de Janeiro coast. The ichthyofauna was sampled in the dry and rainy seasons using gillnets, and the composition, richness, diversity, abundance and biomass per distance unit were recorded. The availability of potential macrobenthic prey was evaluated using a stainless steel corer for each inter-module distance, and the results correlated with the stomach contents of the captured ichthyofauna. Community descriptors did not significantly change with treatments of reef distance. A canonical correspondence analysis revealed similar fish composition among reef distance treatments, but increased occurrence of exclusive species and habitatdependent fish with increased distances among reef modules. Non-metric multidimensional scaling showed different composition of fish populations between sampling periods, with a predominance of Sciaenidae in the dry season and Ariidae and Carcharhinidae on the rainy season. The adjacent infauna was not directly related to the ichthyofauna but to the benthic prey, which were possibly using the structure interstices, and small fish. Significant effects of seasonal freshwater and sediment loads from large regional coastal rivers may override the effects of reef configuration, especially during rainy seasons with higher inflow. As the shorter reef distance exhibited generally the same richness and abundance compared with larger and more distant reefs, a patchy design with \5.0 m distances is thus recommended for the distribution of artificial reefs to increase fish biodiversity in coastal environments with homogeneous substrate and seasonally influenced by freshwater outflow and sediment from large rivers.
We present here the first results of Hg concentrations in three small shark species (Rhizoprionod... more We present here the first results of Hg concentrations in three small shark species (Rhizoprionodon lalandei, R. porosus and Mustelus higmani) from the SE Brazilian coast. Mercury concentrations in R. lalandei ranged from 21.5 to 280.0 ng.g -1 dry weight (d.w.) (average 74.6 ng.g -1 d.w.; 17.9 ng.g -1 wet weight). In R. porosus, concentrations ranged from 7.6 to 90.5 ng.g -1 d.w. (average 42.2 ng.g -1 d.w., 9.4 ng.g -1 wet weight), whereas in M. higmani, concentrations ranged from 13.0 to 162.8 ng.g -1 d.w. (average 54.9 ng.g -1 d.w., 13.4 ng.g -1 wet weight). These concentration ranges are very low compared with values reported for other large shark species of the Southwestern Atlantic Ocean. There was a significant positive correlation between Hg concentrations and individual size, suggesting that biomagnification is occurring in these animals.
ABSTRACT To investigate how variations in the volume of artificial reefs affect the structure and... more ABSTRACT To investigate how variations in the volume of artificial reefs affect the structure and composition of the transient ichthyofauna, reefball-type concrete modules were arranged at 9 m of depth along the northern coast of the state of Rio de Janeiro. The modules were arranged in three configurations, each in triplicate: (1) solitary modules (1 m3), (2) side-by-side modules (2 m3) and (3) modules forming a triangle (3 m3). The surrounding ichthyofauna were sampled in two periods of the year (dry: September 2009 and October 2010; rainy: April 2010 and April 2011) with gillnets to record the richness, species diversity, number of individuals and biomass per volume unit. The total mean values of richness, diversity, number of individuals and biomass did not differ significantly among the reef volumes. However, when these variables were analyzed per standardized volume unit, there was an increase in these variables with the increase in reef volume, considering all the transient ichthyofauna as well as the most representative families, Ariidae and Sciaenidae. A non-metric multidimensional scaling ordination analysis revealed differences in the composition of the ichthyofauna between the sampling periods, dominated by Sciaenidae (Stellifer rastrifer, Paralonchurus brasiliensis, Larimus breviceps and Cynoscion virescens) in the dry period and by Ariidae (Aspistor luniscutis) and Carcharinidae (Rhizoprionodon porosus) in the rainy period. The results suggest that the increase in module size from 1 to 3 m3 may result in slight alterations in the community descriptors, with a decrease in the relative values of richness, diversity and density per standardized volume unit. Furthermore, the effects of the seasonal flow of the Paraíba do Sul River may overlap the effects of reef configuration, mainly in the rainy period with higher flow. The implementation of several dispersed 1 m3 modules seems to be the most favorable configuration to attract transient ichthyofauna, especially Ariidae and Sciaenidae, on the northern coast of the state of Rio de Janeiro.
Journal of the Marine Biological Association of the United Kingdom, 2014
Artificial reefs (ARs) are often used to improve fishing and, consequently, the economy of a regi... more Artificial reefs (ARs) are often used to improve fishing and, consequently, the economy of a region. However, the way in which the species use the reefs may vary between fish assemblages. An assessment was made of the influence of an AR complex on the transient fish population off the northern coast of Rio de Janeiro state and, therefore, two control areas were sampled. Gillnets were used to capture individual fish in six sampling surveys. Cumulative abundance and biomass curves (ABC) were used to assess the possible effects of the reefs on the community’s functional structure. In the dry season, during which the influence of the Paraíba do Sul River is smaller, a larger richness of r-strategy species and juveniles of K-strategy species was observed in the reef area compared with the control areas, suggesting that the AR acts as a protective environment for these species. During the lower river discharge period the results indicated a potential disturbance in the functional structure of the AR fish community and, therefore, a less stable environment relative to the control areas. This ‘instability’ warrants a positive connotation, as it indicates that the artificial reefs are harbouring species that are particularly sensitive to predation, making the reef a powerful tool for maintaining these populations on the northern coast of Rio de Janeiro.
ABSTRACT Spatial variations on the macrobenthic composition and structure associated with artific... more ABSTRACT Spatial variations on the macrobenthic composition and structure associated with artificial reefs (ARs) on the south-eastern Brazil coast were related to particle size and geochemical characteristics of the sediment and to bottom currents velocity in the vicinity of ARs and two control areas (CAs). The sampling periods were related to Paraiba do Sul River (PSR) flow, highest in summer months. The sediment was more heterogeneous near the ARs, composed mainly of mud and gravel and with greater abundance of shellfish compared to the CAs predominated by mud. The influence of the artificial structures on the hydrodynamics of the site was evident with significantly lower current velocity. Macrobenthos richness, abundance and diversity varied spatially, with higher mean values near the ARs in both sampling periods, reinforcing the influence of artificial structures on the associated infauna. Significant temporal differences in the concentrations of phosphorus, nitrogen and dissolved organic carbon only on the CAs suggest that the effect of the artificial structures surpasses the environmental seasonality related to the PSR flow. The artificial modules created a more heterogeneous grain size of the sediment that contributed to the enrichment of associated macrobenthos, with higher species richness and abundance due to a higher niche availability.
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