Rodrigo Santiago Godefroid

Temporal variation in fish assemblage composition on a tidal flat

Annual variation in the fish assemblage characteristics on a tidal flat was studied in coastal Parana, in southern Brazil. Fish were collected between August 1998 and July 1999, during the diurnal high tide and diurnal and nocturnal low tide of the syzygial (full moon) and quadrature (waning moon) tides, to characterize temporal change in assemblage composition. A total of 64,265 fish in 133 species were collected. The average number of species and individuals, biomass, species richness, diversity (mass) and equitability varied significantly over time . The dissimilarity of the assemblage was greatest in August, September and October in contrast with the period from November to January, with the lowest dissimilarity. The combined action of water temperature, salinity and wind intensity had a great influence over the structure of the fish assemblage.

Mudanças temporais na abundância e diversidade da fauna de peixes do infralitoral raso de uma praia, sul do Brasil

Abundance and diversity of the fish fauna in the shallow infralittoral region of Atami Beach, Parana, Brazil, were studied through monthly collections between July 1998 and June 1999. A total of 7553 fishes from 70 species and 26 families, mainly juvenile forms, was captured in the area. The mean captures in number of species, number of fish and biomass were larger from the end of spring to the middle of autumn; seasonal tendency in richness, diversity (number) and equitability indices were not observed. The largest mean dissimilarity in the composition of the ichthyofauna occurred between June and May in comparison to the period between July and October. The species that contributed most to this dissimilarity were Selene setapinnis (Mitchill, 1815), Conodon nobilis (Linnaeus, 1758) and Stellifer rastrifer (Jordan, 1889). Three great groups reflecting patterns of temporal occurrence of the most abundant species were identified.

A study of the fish community structure in a tidal creek

The fish assemblage in a mangrove tidal creek was studied in monthly collections between August 1998 and July 1999 in the quadrature low tide and high tide, using a fyke net of 30 m x 1.5 m and meshes of 8 and 10 mm. Simultaneously with the biological collections, temperature, salinity, pH, water transparency, and current speed data were obtained. The collections resulted in the capture of 36,873 fish representing 22 families and 52 species. Immature individuals abounded (63.8%), and among the adult specimens there was a larger number of females. The species Anchoa parva, Harengula clupeola, Genidens genidens, and Bairdiella ronchus, contributed to 84.9% of the total capture of fish, however the contribution in mass was of 55.2%, indicating a predominance of small individuals. A smaller number of fish and species seem to occupy the area in the period between August and December, in comparison to the period between February and July, when the larger aggregations appear, mainly of the species Anchoa parva, Harengula clupeola, Opisthonema oglinum, Genidens genidens, Diapterus rhombeus, and Bairdiella ronchus. The environmental factors, pH, water transparency, and rainfall seem to have an influence in the structure of the observed biological patterns.

Moon, tidal and diel influences on catch composition of fishes in the surf zone of Pontal do Sul beach, Paraná

Fishes were sampled by beach seine during the day and night at the high and low sygygy tides, on a sandy beach at the southeast coast of Brazil. The quantitative results appear to indicate a larger concentration of fish in the surf zone of this beach, in low tides at the start and end of the day. Only eight from the 17 most abundant taxa, appeared to have been influenced singly or in combination by the factors of the moon, day, night and tide.

Occurrence of Larvae and Juveniles of Eucinostomus argenteus, Eucinostomus gula, Menticirrhus americanus, Menticirrhus littoralis, Umbrina coroides and Micropogonias furnieri at Pontal do Sul beach, Paraná

Apesar da importância, a maioria dos estudos de ictioplâncton na costa sul-sudeste do Brasil, foram realizados sobre a plataforma continental. No que se refere ao ambiente praial, reconhecido como area de criacao, pouco se sabe sobre o ictioplâncton. Foram analisadas 288 amostras coletadas com uma rede tipo picare com 18 x 2 m e malha de 1mm, e rede de plancton conica, com malha de 300 mm e boca de 60 cm. A especie E. argenteus totalizou 78 % das larvas e juvenis capturados. A ocorrencia dos gerreideos foi fortemente concentrada no verao, enquanto que Menticirrhus littoralis, Menticirrhus americanus e Umbrina coroides estiveram presentes em todas as estacoes do ano. M. littoralis foi mais abundante na primavera, enquanto que M. americanus e U. coroides dominaram no inverno. Em todas as especies as maiores capturas ocorreram na baixa-mar. Preferencias ambientais foram indicadas na analise de componentes principais, com as larvas e juvenis de E. argenteus e E. gula positivamente correlacionados com menores ondas e menor morfodinamismo, enquanto que M. americanus, U. coroides e M. furnieri parecem preferir periodos com menores temperaturas e maior morfodinamismo.

Larval fish in the surf zone of Pontal do Sul beach, Pontal do Paraná, Paraná, Brazil

A total of 6,575 larvae in the preflexion, flexion and post-flexion stages of 15 families, 26 genera and 29 species were captured in the surf zone of Pontal do Sul beach, Parana, Brazil. Samples of the families Gerreidae and Scianidae predominated and larvae of Eucinostomus argenteus (Baird&Girard, 1854), Micropogonias furnieri (Desmarest, 1823), Eucinostomus gula (Cuvier, 1830), Menticirrhus ameri-canus (Linnaeus, 1758) and Anchoa tricolor (Agassiz, 1829) were the most dominant species. Greater abundance of larvae was observed during the summer, followed by winter and in a less extent during spring and autumn. The number of species was greater in the summer, and there were no significant differences in the rest of the seasons.