Joaquim Olinto Branco

Reprodutive ecology of the blue crab, Callinectes danae Smith, 1869 in the Conceição Lagoon system, Santa Catarina Isle, Brazil

Abundance of ovigerous females, size of the first gonadal maturation and the possible migration, route of the blue crab Callinectes danae from the Conceição Lagoon system, Santa Catarina Isle, Brazil, are described. This lagoon is connected with the coastal area through a canal. A total of 1,124 crabs was caught during a 19 month sampling period. The reproduction and recruitment of juveniles occurred all year-round, with two peaks of abundance (February and September), correlated with the presence of ovigerous females (June and January). The mean carapace width at which the crabs attained gonadal maturity for the first time was 9.4 cm in males and 8.4 cm in females. The Conceição Lagoon is a growth, reproduction, and spawning area for the species. However, egg eclosion occurs outside the lagoon following migration of ovigerous females to the open sea. After hatching the eggs, some females return to the lagoon, but males stay there for most of their life cycle.

Descartes da pesca do camarão sete-barbas como fonte de alimento para aves marinhas

From July 1996 to June 1997, in Armacao do Itapocoroy, Penha, Santa Catarina State, Brazil, monthly census were done in three areas of traditional fishery and Itacolomis islands. A total of 10021 seabirds were registered, belonging to eight species, five genus and four families. The average number of seabirds per dragging varied between 80,2 and 113,6. Sterna spp, appeared at first in 43,3% of the released by-catch, followed by Larus dominicanus Lichtenstein, 1823, Fregata magnificens Matheus, 1914, Phalacrocorax brasilianus (Humboldt, 1805) and Sula leucogaster Boddaert, 1783. The average size of the fish consumed by the seabirds oscillated from 8,3 cm (Sterna spp.) to 18,5 cm (F. magnificens), with an average time from 6,12 to 7,55 minutes per by-catch released. In general, seabirds use 84,0% of the by-catch fish as a feeding source.

Dinâmica da alimentação natural de Callinectes danae Smith (Decapoda, Portunidae) na Lagoa da Conceição, Florianôpolis, Santa Catarina, Brasil

From March/91 to February/92 monthly collcction surveys were carried out to obtain basic information about the dynamics of feeding and trophic spectrum of C. danae Smith, 1869. A total of 456 males and 527 females were caught. The diet of the species was not sex related. The trophic spectrum of C. danae is composed by a high number of items. The 35 items were assembled in 14 categories and the feeding index was applied. Mollusca, Polychaeta and Crustacea were observed to be basic elements in the species diet, Osteichthyes and MOND appear as secondary resource whereas vegetal material were found to be of less importance.

Biologia e pesca do camarão sete-barbas Xiphopenaeus kroyeri (Heller) (Crustacea, Penaeidae), na Armação do Itapocoroy, Penha, Santa Catarina, Brasil

The artisanal fishery of the sea-bob-shrimp is known as “sun to sun fishery” and is developed in large scale along the Brazilian coast, playing a significant economic, historical, social and cultural role. Nowadays, sea-bob-shrimp fisheries is classified as the highest economic interest and the second fisheries resource in the South-southeast coast of Brazil. Aiming to study the biology and fishery of the sea-bob-shrimp at Armacao do Itapocoroy, Penha (26o40’-26o47’S and 48o36’-48o38’W), 30 minutes samples were performed monthly, from August 1996 to July 2003. Total and standard length, sex, maturation stages, biomass and total number of specimens were registered between 1996-1997 and 1999-2001. Between August 1998 and July 1999, the diet of X. kroyeri (Heller, 1862) was also studied. The species’ total length varied from 3.0 to 16.0 cm and seasonal fluctuations in its abundance and biomass showed higher values along the summer and autumn months. The length/weight relationship indicated an isometric growth and first maturity occurring between 7.3 and 7.9 cm, reached in six months. The species presented two spawning peaks along the year, and the artisanal fishery showed a higher pressure over the adult stock. The trophic spectrum was composed by 30 items, being Gammaridae, sand, other crustaceans and organic matter the basic elements of its diet. A mean value of 67.82 vessels operate yearly during eight months on the sea-bob-shrimp fishery at Armacao do Itapocoroy, yielding a total of up to 170 ton/year.

Population biology and growth of the hermit crab Dardanus insignis at Armação do Itapocoroy, southern Brazil

This study was conducted between January and December 1995 at Armacao do Itapocoroy, Penha, Santa Catarina, southern Brazil. Monthly samples were carried out in the morning, afternoon, and evening using two over-trawls with 6 m at the opening, 3·0-cm mesh at the outer part and 2·0-cm mesh in the bag. Dardanus insignis was collected year round but with higher densities in September and October. The hermit crabs were more abundant during the evening than the afternoon but no differences were recorded between morning and both evening and afternoon. Females were slightly more abundant than males but the sex ratio did not differ from 1:1. Females were more abundant in the smallest size-classes ( 2·2 cm). The individuals of this population of D. insignis have a mean cephalothoracic length of 1·89±0·40 cm (range 1·00 to 3·90 cm) and a mean weight of 40·26±27·06 g. The size distribution showed an unimodal pattern, with males being larger than ovigerous females, which, in turn, were larger than non-ovigerous females. Dardanus insignis showed a seasonal reproductive pattern with a peak from September to November and complete absence of ovigerous females from April to August. The von Bertalanffy growth function (VBGF) with temporal oscillation fitted for this population of D. insignis had the following parameters: L ∞ =4·40 cm, K=0·60, C=0·95, WP=0·35. Recruitment was estimated to start in September and was extended to the following months. Estimates of longevity ranged from 20 to 62 months. A mortality rate of 2·21 was estimated based on the length converted catch curve. The cephalothoracic length of males and females showed, respectively, positive and negative allometry with both cephalothoracic width and crab weight.

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.

Reprodução das aves marinhas nas ilhas costeiras de Santa Catarina, Brasil

Studies involving the reproduction of seabirds in the Santa Catarina coast are scarce. From 1996 to 2002 a sampling program was implanted with the objectives of identifying the ranches, the species and to study some aspects of their reproductive cycle. Five species: Sula leucogaster Boddaert, 1783; Fregata magnificens Matheus, 1914; Larus dominicanus Lichtenstein, 1823; Sterna hirundinacea Lesson, 1831; S. eurygnatha Sauders, 1876, breed in the islands of Santa Catarina, with the largest intensity in the period of May to December. The size of the colonies varied in function of the species and of the reproduction area.

Crescimento de Callinectes danae Smith (Decapoda, Portunidae) da Lagoa da Conceição, Florianópolis, Santa Catarina, Brasil

Studies on the growth of the blue crab C. danae were carried out by the analysis of size-frequency distributions, and the growth curves were determined for both sexes through Bertalanffy equation. 613 males and 511 females were obtained from 10 collecting sites of the lagoon, at night, monthly from January/88 to July/89. The growth curves in carapace width were described according to the following equations: Wid∞ = 14.0 (1-e-0,6975.t) for males and Wid∞ = 13.3 (1-e-0,6555.t) for females. The growth curves in body weigth were also determined, based on the equations of the growth curves and the relationship between body weight and carapace width. The equations are:Wt = 156.9 (1-e-0,6975.t)2.9153 for males, Wt = 134.0(1-e-0.6555.t)2.8994 for 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.