Hélio Augusto Alves Fracasso

Population biology of Callinectes danae and Callinectes sapidus (Crustacea: Brachyura: Portunidae) in the south-western Atlantic

The capture of crabs of the genus Callinectes is one of the oldest extractive activities practised by waterside communities, due to the abundance of brachyurans along the Brazilian coast. The present paper aimed to provide basic information on the population biology of C. sapidus and C. danae during the period of December 2003 to November 2004, in Babitonga Bay, Joinville, Santa Catarina. The size of the first maturation of C. danae was estimated as 7.1 cm in total carapace width for females, and as 8.6 cm for males. Fecundity of the 20 females of C. danae with carapace width from 7.0 to 11.0 cm varied from 618,667 to 811,267 eggs. Fecundity of C. sapidus was higher, with a median of 978,000 eggs per female, but carapace widths in this species were also larger, with the highest frequency of females attaining 19.01 cm on average. In both species, a tendency was observed for the egg mass to increase with size of females. The capture per unit of effort presented the lowest values in summer, while the largest values occurred from March, August and November. A total of 80 males and 127 females of C. sapidus were captured in the four collecting areas, with the largest abundances in Area III (45.18%), followed by Areas II, IV and I. The size of the first maturation of C. sapidus was estimated as 10.2 cm for females and as 9.0 cm for males. Fishing effort was in relative equilibrium for adult stock (males = 58.75% and females = 52.99%) and juveniles (males = 41.25% and females = 47.01%). The largest monthly rates of biomass of C. sapidus occurred from April to November, with a peak of capture in August, without significant differences in the participation of males and females.

Bioecology of the ghost crab Ocypode quadrata (Fabricius, 1787) (Crustacea: Brachyura) compared with other intertidal crabs in the southwestern Atlantic.

ABSTRACT Data sets on the natural dynamics of beach ecosystems arc scarce and fragmentary. Such data arc necessary for implementing more efficient monitoring programs that quantify the dynamics of key ecological attributes on sandy beaches. This article contributes to the bioecology of ghost crabs from subtropical Praia Brava, Itajaí, Santa Catarina. Ocypode quadrata occurs in sandy beaches along the tropical-temperate western Atlantic, from Rhode Island (US) to Rio Grande do Sul (Brazil). During 14 consecutive months, a total of 649 specimens were captured: 255 females (39%), 241 males (37%), and 153 juveniles of undetermined sex (24%). Highest densities were recorded in June and November, with a total of 1,900 burrows distributed along the beach (56.95%) and dunes (43.05%). Sixteen natural diet items were identified for this crab, with a larger participation of Apis spp. (38.97% of relative volume). In the local food web, the ground-burrowing owl Speotyto cunicularia was the main crab predator. This article indicates that the ghost crab represented the second most consumed food item of the owl (29.24%), only surpassed by rodent remains, which occupied 50.32% of its stomach volume. The natural diet and the main predator of the ghost crab had not been observed along the coast of Brazil. Knowledge of natural diet is fundamental for understanding distribution patterns, migrations, and molting cycles. Further information on population structure (abundance peaks in spring and summer; a negative allometric growth pattern), spatial distribution (predominance of females in August and May, and of males in July; size of specimens increases toward higher intertidal levels), sexual proportion throughout the year (reproduction is continuous), form and disposition of burrows (reduced abundance toward the higher tidal levels), and relative importance for the diet of the main predator (both predator and prey arc nocturnal) may be used as instruments for evaluating the occupational impact and for conserving natural dune and beach environments along sandy beach ecosystems. In conclusion, ghost crabs provide an alternative source of food for the ground-burrowing owl, a predator that may represent an important population controlling factor, other than the human-induced impacts on sandy beaches. Although burrowing crabs are the most conspicuous and ecologically important invertebrates of intertidal beaches along tropical and temperate regions, factors that regulate abundance arc still controversial, whereas the biotic community interactions in sandy beaches remain barely known.

Population biology of Callinectes ornatus (Ordway) in the Armação do Itapocoroy, Santa Catarina, Brazil

Callinectes ornatus (Ordway, 1863) e a especie mais abundante de Portunidae, capturada como fauna acompanhante na pesca artesanal do camarao sete-barbas. Durante o periodo de Agosto de 1996 a Julho de 2002, os caranguejos foram monitorados mensalmente na Armacao do Itapocoroy. C. ornatus mostrou flutuacoes sazonais na abundância com as maiores taxas na primavera e no inverno. A variacao da populacao quando a largura da carapaca variou de 2,0 a 10,0 cm, e a presenca de juvenis foi comum ao longo do ano. As especies apresentaram crescimento alometrico positivo, com os machos e as femeas chegando a primeira maturacao gonadal com 5,8 e 5,2 cm, respectivamente. A pesca artesanal na Armacao do Itapocoroy atua com alta intensidade sobre o estoque adulto.

Ocorrência e abundância de Rynchops niger Linnaeus, no litoral de Santa Catarina, Brasil

The black skimmer inhabits the great rivers, lakes and coastal areas during the migrations, in South and North America. This work aims to make available basic information about the occurrence and abundance of the black skimmer in the coast of Santa Catarina. From April/2002 to May/2003 seasonal censuses were accomplished, and monthly in Itajai, with aid of binoculars 10 x 50. The black skimmer is more frequent in the embankment of the South Bay (Florianopolis), in the summer and autumn, in the spring-summer in Sao Jose and Tijucas and in the autumn-winter in the estuary of the Saco da Fazenda (Itajai). In this estuary, the population presented accentuated flotation along the year, with the largest abundances happening in August/2001, January/2002 and March/2003.

A comparison of foraging between the South American and Cabot's Tern in southern Brazil

Despite being widely distributed in South America and having relatively large populations, little is known about the trophic ecology of the South American Tern (Sterna hirundinacea) and Cabots Tern (Thalasseus acuflavidus). In Brazil, South American and Terns Cabots breed in mixed colonies from the state of Espirito Santo to Santa Catarina. Here, we describe results of a study of the feeding ecology of these two species during the reproductive seasons of April to October of 2003, 2005 and 2006 from Cardos Island, Santa Catarina, Brazil. A total of 6248, 5140, and 4006 fishes were delivered to chicks or females by South American Terns; and 1157, 628 and 98 fish and or other prey items by Cabots Terns during the breeding seasons of 2003, 2005, and 2006, respectively. Prey items identified included eight, seven and nine fish families for South American Terns; and, five, three and two families for Cabots terns, in the three respective years. The number of food deliveries per chick for South American Terns was between 09:00 and 10:00 am in 2006, and between 11:00 and 12:00 am in 2005. Cabots Terns chicks were fed in the early hours of the morning until late afternoon.

Ten-year variations in population structure of pink-shrimp in a southwestern Atlantic Bay affected by highway construction

OBJECTIVES: Population structures of Farfantepenaeus brasiliensis and F. paulensis, consisting mainly of juveniles, were evaluated during the construction of an expressway along a mangrove area. Estuarine regions in southern Brazil function as sites for reproduction, nursery and growth of a variety of organisms, including two of the most important species of shrimp for fisheries in the southwestern Atlantic. Shrimps were collected in Saco dos Limoes creek, Baia-Sul, Florianopolis, State of Santa Catarina, four times a year, by day and night, between 1997 and 2006. Fluctuations in the abundances of shrimp appear to be related to their life cycles, with largest abundances in Summer and Spring, rather than to impacts promoted by dredging activities during the expressway construction.

Biodiversidade no estuário do Saco da Fazenda, Itajaí-SC

ReSumo: Os estuarios se caracterizam por apresentar uma elevada produtividade biologica como areas vitais da alimentacao, reproducao, cuidado e atracao para uma grande diversidade de organismos. Mas o aumento da ocupacao humana associado a exploracao economica intensiva causou um aumento gradual da degradacao do habitat destas areas. Saco da Fazenda (Itajai, Santa Catarina) sofre de intenso impacto antropico, recebendo aguas de esgoto domestico, residuos solidos, e atividades de dragagem. O objetivo deste trabalho foi analisar a composicao quali-quantitativa dos crustaceos, peixes e passaros, e os impactos provaveis das atividades de dragagem em suas especies. 51 especies, 42 generos e 23 familias compuseram a ictiofauna, sendo o salmonete branco, Mugil curema, a especie mais abundante em 2001-2002 e em 2003-2005, enquanto a anchova, Lycengraulis grossidens, e a carapeba, Diapteurs rhombeus, foram dominantes em 2000-2001 e em 2002-2003 respectivamente. Os caranguejos e camaroes verdadeiros se distribuem entre cinco familias e dez especies, e a mais abundante e a Callinectes danae. Os caranguejos foram representados por cinco especies e duas familias, sendo Uca uruguayensis a especie mais abundante. As aves foram caracterizadas por 50 especies, sendo sete classificadas como aves litorâneas, 39 aves de habitos limicolas e quatro especie habitantes ou visitantes da Floresta Atlântica. As familias Ardeidae, Scolopacidae, Laridae e Charadriidae contribuiram com 64,0% das especies, sendo a Phalacrocorax brasilianus (Gmelin, 1789) e a Larus dominicanus, Lichtenstein 1823 predominantes. Apesar da degradacao bentica do habitat e da mortalidade de especimes Ariidae, Paralichthydae e Portunidae durante o periodo de atividades de dragagem, foi observado um aumento na abundância e riqueza de especies apos a realizacao destas atividades, associada provavelmente ao aumento da profundidade, que melhorou os padroes locais de circulacao da agua, favorecendo assim a entrada de peixes e crustaceos no ecossistema. PalavRaS-Chave: Biodiversidade. Impacto ambiental. Solo - ocupacao.