Entity

Time filter

Source Type


Guebert-Bartholo F.M.,Federal University of Pernambuco | Barletta M.,Federal University of Pernambuco | Barletta M.,Institute Ecologia E Gerenciamento Of Ecossistemas Aquaticos Iegea | Costa M.F.,Federal University of Pernambuco | And 3 more authors.
Endangered Species Research | Year: 2011

This study investigated use of the Paranaguá Estuary as a foraging habitat by juvenile green turtles Chelonia mydas (L.) by comparing gut contents to available vegetal resources within the estuary. Between June 2004 and July 2007, the carcasses of 80 juvenile green turtles (carapace length range 29 to 73 cm) were found stranded (n = 71) or captured (n = 9) in fishing nets. The digestive tracts of 76 turtles contained food contents which were quantified (ml) and identified (e.g. algae, seagrass, mangrove propagules, mangrove vegetation and shells). Anthropogenic debris was classified by material, colour and size. Green turtles fed primarily on Halodule wrightii (42.9% of total volume), other vegetal resources (Ulva spp.: 6.7%; Avicennia shaueriana propagules: 10.1%) and other items (37.9%); ingested animal matter was seldom recorded (2.4%). The occurrence and/or availability of vegetal resources were assessed throughout the year. H. wrightii was ingested more frequently during the early rainy season, when the index of importance in the diet was higher (feeding index, FI: 97.3). Ulva spp. was ingested principally in the late dry season and A. shaueriana propagules in the late rainy season (FI: 23.9 and 12, respectively), when H. wrightii was not available. Anthropogenic debris was frequently ingested (69.7% of individuals), and was especially important in the late rainy season (FI: 60.3). This study highlights the importance of sheltered ecosystems such as the Paranaguá Estuary and adjacent regions in providing shelter, feeding grounds and resting areas for juvenile green turtles. © Inter-Research 2011. Source


Dantas D.V.,Federal University of Pernambuco | Dantas D.V.,Institute Ecologia E Gerenciamento Of Ecossistemas Aquaticos Iegea | Barletta M.,Federal University of Pernambuco | Barletta M.,Institute Ecologia E Gerenciamento Of Ecossistemas Aquaticos Iegea | And 2 more authors.
Environmental Science and Pollution Research | Year: 2012

Introduction: Artisanal fisheries in tropical estuaries are an important economic activity worldwide. However, gear (e. g. ropes, nets, buoys, crates) and vessels are often in use under dangerous conditions. Polyfilament nylon ropes are used until they are well beyond human and environmental safety limits. Severe wear and tear results in the contamination of the environment with micro-fragments. The spread of these fragments in the marine environment and their ingestion by the biota are documented in the scientific literature and are increasing concerns. The aim of this study was to evaluate the ingestion of plastic fragments by two fish (drum) species in relation to seasonal, habitat and fish size-class variation. Materials and methods: The stomach contents of 569 individuals of Stellifer brasiliensis and Stellifer stellifer from the main channel of the Goiana Estuary were examined to identify variation in the number and the weight of plastic fragments and relate this variation to differences among the seasons (early dry, late dry, early rainy and late rainy), the habitats within the estuary (upper, middle and lower) and the size classes of the fish (juveniles, sub-adults and adults). Results: Plastic fragments were found in 7. 9% of the individuals of these two drum species captured from December 2005 to August 2008. Nylon fragments occurred in 9. 2% of S. stellifer and 6. 9% of S. brasiliensis stomachs. The highest number of nylon fragments ingested was observed in adults during the late rainy season in the middle estuary. Discussion: Blue polyfilament nylon ropes are used extensively in fisheries and can be lost, inappropriately discarded or damaged during use in the estuary. These fragments were the only type of plastic detected during this study. The ingestion of nylon fragments by fish probably occurred during the animals' normal feeding activities. During the rainy season, the discharge of freshwater transports nylon fragments to the main channel and makes the fragments more available to fish. Fishery activities are responsible for a significant amount of the marine debris found in the estuary. Conclusions: The ingestion of fragments of nylon threads by fish is a demonstrated form of pollution in the Goiana Estuary. The physiological and toxicological consequences of the ingestion of this type of debris are unknown, as is the actual extent of the problem worldwide. The solutions to the problem are in the hands of authorities and communities alike because the good care and timely replacement of gear requires education, investment and effective policies. © 2011 Springer-Verlag. Source


Dantas D.V.,Federal University of Pernambuco | Dantas D.V.,Institute Ecologia E Gerenciamento Of Ecossistemas Aquaticos Iegea | Barletta M.,Federal University of Pernambuco | Barletta M.,Institute Ecologia E Gerenciamento Of Ecossistemas Aquaticos Iegea | And 6 more authors.
Estuaries and Coasts | Year: 2012

The seasonal and spatial distribution (density and biomass) of five size classes of two catfish species (Cathorops spixii and Cathorops agassizii) were studied along an estuarine ecocline to test the relative importance of the nursery function of each habitat. Seasonal vs. area interactions were significant for all size classes of both species. During the early rainy season, the middle estuary is an important nursery habitat for juveniles of both species. When environmental conditions change during the late rainy season, the C. spixii primary nursery habitat shifts to the lower estuary. During this period, juveniles of C. agassizii remain in the middle estuary. Another important ecological area is the upper estuary, which becomes a breeding, spawning and hatchery area during the late dry season for both species. The nursery function of habitats shifts according to the seasonal fluctuation of salinity and dissolved oxygen, and each species responds differently to this change. © 2011 Coastal and Estuarine Research Federation. Source


Dantas D.V.,Federal University of Pernambuco | Dantas D.V.,Institute Ecologia E Gerenciamento Of Ecossistemas Aquaticos Iegea | Barletta M.,Federal University of Pernambuco | Barletta M.,Institute Ecologia E Gerenciamento Of Ecossistemas Aquaticos Iegea | And 7 more authors.
Estuaries and Coasts | Year: 2013

This study describes the seasonal feeding habits of different size classes of Cathorops spixii and Cathorops agassizii along an estuarine ecocline and the food overlap when different size classes occur together. These species were essentially zoobenthivorous, feeding mainly on Polychaeta Nereis sp., Copepoda Pseudodiaptomus acutus, Ostracoda Asterope sp., Gastropoda: Littorinidae, and Bivalvia Mytilus sp. and Anomalocardia brasiliana. However, during their life cycle and between different habitats and seasons, their trophic guild can change to zooplanktivore. The competition for resources was observed among C. spixii and C. agassizii, but was significantly reduced due to the seasonal diference in habitat use by different ontogenetic phases in the main channel of the estuary. The food niche separation was strongly influenced by environmental fluctuations, principally of salinity, resulting from rainfall and river inflow. High abundance of some preys, such as P. acutus (all estuary), Asterope sp. (upper and middle estuary), and Littorinidae (upper and lower estuary), could influence the significant diet overlap, principally during the rainy season, and call for more detailed studies of the benthic community structure. Moreover, dietary overlap was observed mainly between smaller sizes (intraspecific and/or interspecific) or between corresponding ontogenetic phases (interspecific), suggesting some differentiation in the diet in relation to the size class. Differences in prey type and size between the different ontogenetic phases of these ariids, principally among juveniles and adults, could be related to the size of the mouth, since adults are able to successfully capture larger preys or larger quantities of particular items. © 2012 Coastal and Estuarine Research Federation. Source


Dantas D.V.,Federal University of Pernambuco | Dantas D.V.,Institute Ecologia E Gerenciamento Of Ecossistemas Aquaticos Iegea | Barletta M.,Federal University of Pernambuco | Barletta M.,Institute Ecologia E Gerenciamento Of Ecossistemas Aquaticos Iegea | And 8 more authors.
Journal of Fish Biology | Year: 2010

From December 2005 to November 2006, 216 samples were taken from the main channel of the Goiana Estuary, representing a total sampled area of 23 ha. Ariidae species were the most abundant in density (1600 individuals ha-1, 53%) and biomass (18 813 g ha-1, 63%). Cathorops spixii was the most abundant in density (1340 individuals ha-1) and biomass (14 203 g ha-1). The variables: number of species, total density and biomass, showed significant interactions between the factors of areas and seasons (P < 0·01). The highest total density (7394 individuals ha-1) and biomass (70 292 g ha-1) occurred in the middle and upper estuaries, respectively, during the early-rainy season. The density of C. spixii differed significantly between areas and seasons (P < 0·01), while Cathorops agassizii differed significantly only between seasons (P < 0·01). The biomass differed significantly for the species C. spixii, C. agassizii and Sciades herzbergii between seasons, and C. spixii and C. agassizii between areas. Also, the density and biomass of C. spixii and C. agassizii showed interaction between areas and seasons. Only the biomass of S. herzbergii showed interaction between areas and seasons (P < 0·01). This indicates that seasonal variations influenced the distribution of Ariidae species in the different areas of the Goiana Estuary. Moreover, canonical correspondence analysis highlighted a strongly significant correlation (P < 0·01) between the seasonal variations of the environmental gradients (salinity and water temperature) and distribution of catfishes. The management and conservation of estuaries should take into account the life cycle of these species in different estuarine areas and hydrological seasons. © 2010 The Authors. Journal compilation © 2010 The Fisheries Society of the British Isles. Source

Discover hidden collaborations