Larval fish of the Campos Basin, southeastern Brazil (original) (raw)
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Seasonal variation in fish larvae at the entrance of Guanabara Bay, Brazil
Brazilian Archives of Biology and Technology, 2005
Studies were carried out to find out qualitative and quantitative temporal variations in fish larvae to relate seasonal, diurnal and tidal cycles to the density of larvae. Sampling was performed at one station, during two three-day periods in September 1995 and March 1996. Samples were collected during ebb and flood tides,in oblique hauls using a bongo net of 500 µm mesh size. A total of 42 taxa were identified. The families Engraulidae (Cetengraulis edentulus, Anchoa lyolepis) and Clupeidae (Harengula jaguana) had high mean densities and dominated both periods. Higher larval mean densities occurred in March, a period of relatively high temperatures and low salinities. The diurnal pattern of larval abundance consisted of high densities at night and low densities during the day. The observed diversity values stress the importance of this system for the maintenance of many species of fishes.
Structure and Seasonal Dynamics of Larval Fish in the Caeté River Estuary in North Brazil
Estuarine, Coastal and Shelf Science, 2002
The larval fish assemblage was examined along a salinity gradient of the Caeté River Estuary situated in northern Brazil. A total of 35 555 larvae, representing 28 families and 63 taxa were collected in samples taken monthly between July 1996 and September 1997, with a mean concentration of 9 individuals per 100 m 3. Sciaenidae was the most abundant family comprising 46•5% (11 species) of all teleosts sampled in the Caeté River Estuary, followed by Engraulidae (41•9%, seven species). The most abundant larval taxa were the engraulid Anchovia clupeoides and the sciaenid Stellifer microps accounting together for 70•4% of the total catch. The most abundant developmental stages of A. clupeoides was preflexion larva, confirming that this species is resident. Apart from estuarine species, the upper estuary additionally has taxa associated with freshwater conditions, whereas species with marine affinities were captured in the lower estuary. The densities of most species were influenced to a greater degree by site than by season, showing maximum densities in the upper estuary. Larval density peaked in the upper estuary during the dry season and was lowest when freshwater discharge was at its maximum, which was attributed to an increased seaward drift of larvae. Species number was greatest in the upper estuary between the rainy and dry season.
Environmental Biology of Fishes, 2005
We sampled the Baía River (Mato Grosso do Sul State, Brazil) monthly, to survey taxonomic composition and temporal and spatial distribution of fish larvae. The ichthyoplankton was mainly composed by larvae of small and medium sized sedentary species and it was numerically dominated by six taxa: Plagioscion squamosissimus, Hypophthalmus edentatus, Hoplias aff. malabaricus, Bryconamericus stramineus, Serrasalmus spp. and Catathyridium jenynsii. These taxa present distinct temporal and spatial occurrence patterns: H. edentatus, B. stramineus and C. jenynsii are abundant between September and March in lentic areas; H. aff. malabaricus and Serrasalmus spp. were caught between October and February in lotic areas; whereas P. squamosissimus occurs in all sampled areas, with peak of capture in January. Hypophthalmus edentatus, H. aff. malabaricus, Serrasalmus spp. and B. stramineus were the taxa that most contributed to structure the assemblages temporally and spatially, and their abundances were influenced by the interaction of several environmental variables.
Patterns in larval fish assemblages under the influence of the Brazil current
Continental Shelf Research, 2014
The present work investigates the composition of larval fish assemblages in the area under the influence of the Brazil Current (BC) off the Southeastern Brazilian Bight. Ichthyoplankton was sampled during two oceanographic cruises (November-December/1997spring; May/2001autumn) with bongo nets oblique tows. Seasonal variation and a coastal-ocean pattern in the distribution of larval fish was observed and was influenced by the dynamics of the water masses, Coastal Water (CW), Tropical Water (TW) and South Atlantic Central Water (SACW), the last two of which were transported by the BC. During spring, the shelf assemblage was dominated by larvae of small pelagic fishes, such as Sardinella brasiliensis, Engraulis anchoita and Trachurus lathami, and was associated with the enrichment of shallow water by the SACW upwelling. In autumn, the abundance of coastal species larvae was reduced, and the shelf assemblage was dominated by Bregmaceros cantori. A transitional assemblage occurred during the spring, and comprised mesopelagic and coastal species. In both seasons, the oceanic assemblage was dominated by the mesopelagic families, Myctophidae, Sternopthychidae and Phosichthyidae. The oceanographic conditions also demonstrated clear differences between the northern and southern subareas, particularly in the shelf zone. This was especially the case during autumn when a latitudinal gradient in larval fish assemblages became more pronounced.
The objective of this study was to assess the abundance, attributes of assemblages, and spatial and temporal distributions of fish larvae and their relationships with some abiotic variables in two floodplain lakes with different degrees of connection to the Paraná River in Ilha Grande National Park, PR, Brazil. Four sampling sites were chosen, two in each floodplain lake. Night samples were taken with plankton nets during three spawning seasons (monthly, from October to March) from 2001 to 2005. The highest diversity and abundance were recorded at Saraiva Lake, with 25 taxa being identified. In Xambrê Lake, only sedentary species were captured, and the most abundant species were Plagioscion squamosissimus and Hypophthalmus edentatus. The greatest abundance of larvae was found in the second spawning season. In the Saraiva Lake, the most abundant species were Moenkhausia aff. intermedia, Hyphessobrycon sp., and Bryconamericus stramineus, but larvae of known migratory species were also documented. In this lake, the greatest abundance of larvae was found in the third spawning. Larvae abundance was influenced by water temperature and conductivity. The high diversity and abundance recorded in Saraiva Lake may be a result of its connectivity with the Paraná River, and the low diversity and abundance observed at Xambrê Lake are likely due to its isolation from the river. This work shows the importance of these lagoons for fish development, for both sedentary and migratory species. Both lagoons may be considered to have extreme ecological importance and they are also extremely susceptible to impacts, so any careless disturbance may cause irreversible damage.
Journal of Marine Systems, 2010
Abundance and composition of marine benthic communities have been relatively well studied in the SE Brazilian coast, but little is known on patterns controlling the distribution of their planktonic larval stages. A survey of larval abundance in the continental margin, using a Multi-Plankton Sampler, was conducted in a cross-shelf transect off Cabo Frio (23°S and 42°W) during a costal upwelling event. Hydrographic conditions were monitored through discrete CDT casts. Chlorophyll-a in the top 100 m of the water column was determined and changes in surface chlorophyll-a was estimated using SeaWiFS images. Based on the larval abundances and the meso-scale hydrodynamics scenario, our results suggest two different processes affecting larval distributions. High larval densities were found nearshore due to the upwelling event associated with high chlorophyll a and strong along shore current. On the continental slope, high larval abundance was associated with a clockwise rotating meander, which may have entrapped larvae from a region located further north (Cabo de São Tomé, 22°S and 41°W). In mid-shelf areas, our data suggests that vertical migration may likely occur as a response to avoid offshore transport by upwelling plumes and/or cyclonic meanders. The hydrodynamic scenario observed in the study area has two distinct yet extremely important consequences: larval retention on food-rich upwelling areas and the broadening of the tropical domain to southernmost subtropical areas.
2009
This study investigated the variation in abundance, distribution and composition of ichthyoplankton in a lagoon in southern Brazil through the year and at different stations within the lagoon. Ibiraquera Lagoon is a shallow coastal lagoon connected to the sea by a semi-permanent sandbar. Ichthyoplankton samples were collected monthly from December 2003 to December 2004, with a 200 μm mesh net using horizontal surface hauls. A colder, drier period was detected, contrasting with warm months during which salinity varied depending on rainfall and whether the sandbar was open or closed. The mean abundance of ichthyoplankton over the study period was 459.6 ± 76.2 (SE) eggs · 100 m-3 and 63.6 ± 7.9 (SE) larvae · 100 m-3, and they were present during all months. Significantly higher abundances of eggs and larvae were observed during warm months. The community was dominated by the family Engraulidae followed by Clupeidae, Gobiidae and Mugilidae. Engraulidae and Clupeidae were present throughout the year, with greater abundances in months with higher temperatures. Some coastal fish species spawn in Ibiraquera Lagoon, mainly near to the sandbar, demonstrating that the lagoon is a spawning area for coastal stock. We recommend the establishment of environmental procedures to promote the conservation of Ibiraquera Lagoon and its ichthyoplankton community.
Neotropical Ichthyology, 2010
An analysis was made of the spatial and temporal distribution of the abundance and composition of fish larvae assemblies, aiming to ascertain correlations with biotic and abiotic factors in marginal lagoons of the Cuiabá River floodplain in Brazil's Pantanal wetlands. Samples were collected bimonthly in the pelagic region of the marginal lagoons (fourteen lagoons) close to the littoral zone covered by aquatic macrophytes from December 2006 to April 2007. The captured individuals consisted of 2,739 larvae, represented predominantly by Triportheus spp. (Characidae), Parodontidae, Anostomidae, Characidae and Serrasalmidae. Larval density varied among the sample lagoons in December, but the biotic (zooplankton density) and abiotic (water temperature, electrical conductivity, dissolved oxygen, pH, water transparency and lagoon depth) factors did not significantly affect larval composition and abundance. Larvae were captured throughout the sample period, with the highest densities oc...
Spatial and temporal variations in fish larvae assemblages of Ilha Grande National Park, Brazil
Ecology of Freshwater Fish, 2012
For understanding the reproductive dynamics of fish assemblages and their relationship with environmental conditions, we need to know more about spawning areas and periods. Studies on temporal and spatial patterns of occurrence of fish eggs and larvae are important for obtaining this kind of information quickly and accurately. In this study, we analysed spatial and temporal patterns of fish larvae in different biotopes in a stretch of the floodplain of Upper Parana River, in Ilha Grande National Park, southern Brazil. We carried out night sampling during six spawning periods, from 2001 to 2008. We selected 18 sampling sites distributed in the mainstream, tributaries and lagoons, encompassing several types of biotopes. We observed significant spatial and temporal differences among biotopes in the composition and structure of the fish larvae assemblages. Lentic environments favoured the development of sedentary and migratory species, whereas tributaries were used as migratory routes and spawning areas. The assemblage in period I differed from the assemblages of other periods, probably because of the presence of dams in the Parana River. No association was observed between environmental variables and spatial and temporal patterns of the ichthyoplankton assemblages. Hence, conservation measures are essential to maintain the environmental integrity of spawning (tributaries) and development areas (lagoons) for the maintenance of biodiversity in the floodplain of Upper Paraná River.