Adilson Fransozo

Fecundity of the crab Callinectes ornatus Ordway, 1863 (Decapoda, Brachyura, Portunidae) from the Ubatuba region, São Paulo, Brazil

[The objective of the present study was to characterize the fecundity of Callinectes ornatus from the northern coast of Sao Paulo, Brazil. To study the fecundity and its relationships to size, brood weight, and egg size, the ovigerous females were collected at 2-month intervals for two consecutive years (January, 1991 to November, 1992) in the Ubatuba region using a fishing boat equipped with an otter-trawl type of net. After collecting, the animals were screened, bagged, labeled, and stored frozen. Only data from 38 females carrying early stage eggs were considered. In the laboratory, the specimens were thawed at room temperature, the pleopod structure with the egg mass was removed and the eggs were carefully removed from the pleopods. The samples were then fixed in 10% formalin and stored in 70% ethanol, until the time for processing. Processing followed the method of Hines (1982, 1988). Following the frequency determination of carapace width and fecundity, mean egg number, mean volume and mean dry weight of brooded egg mass were determined for each class obtained. Data were analyzed by regressions of log-log transformations for allometric plots (Y = aXb) of reproductive variables versus carapace width. Carapace width was one of the main factors for the determination of fecundity, which ranged 171 570 ± 94 634 eggs, with females of the same size class presenting a wide amplitude of variation. This supports the hypothesis that portunid females present staggered spawning, possibly presenting more than one period of reproduction within one year. The present species showed lower fecundity than the remaining portunids studied, but they did show a rapid and efficient embryonic development, presumably capable of assuring reproductive success., The objective of the present study was to characterize the fecundity of Callinectes ornatus from the northern coast of Sao Paulo, Brazil. To study the fecundity and its relationships to size, brood weight, and egg size, the ovigerous females were collected at 2-month intervals for two consecutive years (January, 1991 to November, 1992) in the Ubatuba region using a fishing boat equipped with an otter-trawl type of net. After collecting, the animals were screened, bagged, labeled, and stored frozen. Only data from 38 females carrying early stage eggs were considered. In the laboratory, the specimens were thawed at room temperature, the pleopod structure with the egg mass was removed and the eggs were carefully removed from the pleopods. The samples were then fixed in 10% formalin and stored in 70% ethanol, until the time for processing. Processing followed the method of Hines (1982, 1988). Following the frequency determination of carapace width and fecundity, mean egg number, mean volume and mean dry weight of brooded egg mass were determined for each class obtained. Data were analyzed by regressions of log-log transformations for allometric plots (Y = aXb) of reproductive variables versus carapace width. Carapace width was one of the main factors for the determination of fecundity, which ranged 171 570 ± 94 634 eggs, with females of the same size class presenting a wide amplitude of variation. This supports the hypothesis that portunid females present staggered spawning, possibly presenting more than one period of reproduction within one year. The present species showed lower fecundity than the remaining portunids studied, but they did show a rapid and efficient embryonic development, presumably capable of assuring reproductive success.]

Chave ilustrada para identificação dos camarões dendrobranchiata do litoral norte do estado de São Paulo, Brasil

This study aimed to provide an illustrated identification key to distinguish Dendrobranchiata marine shrimps which, occur in the littoral north Sao Paulo State as deep as to 40m. A total of 13 species were captured using a shrimp fishery boat with two double-rig nets. Monthly trawlings were carried out from 1995 to 2000 in the region of Ubatuba, SP. This key includes the commercial value of species such as the penaeids Xiphopenaeus kroyeri, Farfantepenaeus brasiliensis, F. paulensis, Litopenaeus schmitti, Artemesia longinaris and the solenocerids Pleoticus muelleri. In addition to these species, shrimps that are not of commercial interest were also include such as Rimapenaeus constrictus, Acetes americanus, Peisos petrunkevitchi and the sicionids Sicyonia dorsalis, S. typica, S. laevigata and S. parri. The key proposed here might facilitate the identification of Dendrobranchiata shrimps by a variety of users, including scientific researchers as well as people responsible for making the laws that regulate fisheries, principally in the protection period.

Reproductive biology and moulting cycle of the crab Callinectes ornatus (Decapoda, Portunidae) from the Ubatuba region, Sao Paulo, Brazil

Departamento de Biologia Faculdade de Filosofia Universidade de Sao Paulo, Av. Bandeirantes, 3900, CEP 14040-901, Ribeirao Preto, SP

Sexual Maturity of the Speckled Swimming Crab Arenaeus Cribrarius (Lamarck, 1818) (Decapoda, Brachyura, Portunidae), in the Ubatuba Littoral, São Paulo State, Brazil

The sizes at morphological and physiological maturity of male and female Arenaeus cribrarius were estimated to determine if both events are synchronous. Animals were captured with otter-trawls at Ubatuba, Brazil. A total of 2 356 specimens, 977 males and 1 379 females, were obtained. The major carapace width without spines (CW), the propodus length of the major cheliped (PL) and the width of the 5 th abdominal somite (AW) were measured with vernier calipers. Allometric relationships and gonadal development were analyzed to determine the maturity in both sexes. The size at the onset of male morphological maturity was estimated at CW 52 mm, smaller than the CW 63.4 mm physiological maturity size observed. For females, these events are synchronous since both estimates converged at CW 59.7 mm. The onset of functional sexual maturity in A. cribrarius at CW 63.4 and 59.7 mm in males and females, respectively, would indicate a minimum size of CW 64 mm for fishing purposes. Differences between allometric and gonadal estimates indicate the importance of considering both methods. A comparison of the present results with other available data in portunid crabs is provided.

Population structure and reproductive period of the tropical hermit crab Calcinus tibicen (Decapoda : Diogenidae) in the region of Ubatuba, São Paulo, Brazil

ABSTRACT The population of the hermit crab Calcinus tibicen in the Ubatuba region was studied with emphasis on seasonal abundance, seasonal size-frequency distribution, sex-ratio, and reproductive period based on the percentage of ovigerous females. The animals were collected at 2-month intervals for 2 consecutive years (from January 1993 to November 1994). Total mean animal size in shield length was 5.14 ± 1.23 mm for males, 4.23 ± 0.79 mm for females, and 4.53 ± 0.60 for ovigerous females. A discontinuity in reproduction was observed, with an absence of ovigerous females in July (winter) and a high incidence from September to May (spring to autumn). Calcinus tibicen is sexually dimorphic in relation to size, with a higher growth rate in males. The sex-ratio pattern changes with season, indicating that it is more a function of season or habitat than of size.

LATITUDINAL VARIATION IN POPULATION STRUCTURE AND REPRODUCTIVE PATTERN OF THE ENDEMIC SOUTH AMERICAN SHRIMP ARTEMESIA LONGINARIS (DECAPODA: PENAEOIDEA)

Abstract Population structure and reproductive maturity of females were investigated in the shrimp Artemesia longinaris Bate, 1888 from coastal waters of northern São Paulo State (Brazil, 23°S) and Mar del Plata (Argentina, 38°S) from June 2001 to May 2002. Monthly collections were taken by commercial shrimp fishing boats equipped with bottom trawl nets. Population parameters from size frequency distributions and size (carapace length = CL) of female reproductive maturity were analyzed and compared from the two sampling areas. Latitudinal trends in reproductive parameters of A. longinaris were shown in overall body size and size of reproductive maturity, both of which were smaller in females from the tropical location than those from the cold-temperate sampling area. Largest females (> 30 mm CL) were collected in Argentina, while Brazilian specimens reached maximum size at 27 mm CL. The smallest size of female sexual maturity was estimated at 13.6 mm CL in Brazilian samples compared to 22.1 mm CL calculated for those from Argentina. Populations from both regions exhibited a bimodal size distribution in the spring, with the peak at small body size probably corresponding to recent recruits and the peak at larger body size to reproductive females or shrimps migrating in from deeper waters or other latitudinal regions. In late spring and summer, an intrusion of the cold South Atlantic Coastal Water mass was observed which lowered water temperature and stimulated plankton production, the primary food source for the larvae of a typically cold-temperate species such as A. longinaris. The trend of increasing body size and delay of sexual maturity with increasing latitude appears to be correlated with the decreasing water temperature and increasing plankton productivity at higher latitudes.

REPRODUCTIVE CYCLE AND RECRUITMENT PERIOD OF OCYPODE QUADRATA (DECAPODA, OCYPODIDAE) AT A SANDY BEACH IN SOUTHEASTERN BRAZIL

Abstract The reproductive cycle and recruitment period of a ghost crab population from Ubatuba, São Paulo, Brazil were investigated by means of examining the developmental stages of gonads of breeding crabs and the ingress of young recruits to the studied population. Monthly collections over a one-year period were carried out during nocturnal low-tide periods at “Vermelha” beach. The morphology of the abdomen and pleopods was used for sex determination. All captured crabs were measured for carapace width and dissected for the determination of the development stage of the gonads. A total of 582 specimens was captured: 271 males, 241 females, and 70 juveniles. Size ranged from 8.5 to 37.5 mm for males, from 9.5 to 39.2 mm for females, and from 5.8 to 12 mm for early juveniles. Median size of males and females did not differ statistically. The frequency of ovigerous females was markedly low. The onset of sexual maturity in females is achieved at around 23 mm of carapace width. Mature females with advanced gonad stages were not recorded from May to September. Recruitment of young was highest during summer, but the presence of early and late juvenile specimens throughout the year indicates that continuous recruitment is taking place in the studied population.

REPRODUCTIVE BIOLOGY OF THE SHRIMP RIMAPENAEUS CONSTRICTUS (DECAPODA, PENAEIDAE) IN THE UBATUBA REGION OF BRAZIL

Abstract Sexual maturity, temporal reproductive pattern, and recruitment of juveniles were examined for the shrimp Rimapenaeus constrictus at three different bays in the Ubatuba region (Mar Virado, Ubatuba, and Ubatumirim), State of São Paulo (23°S 45°W). Monthly samples were taken from January 1998 to December 1999. The presence or absence of mating plugs (associated with mating and insemination) and ovarian maturity were used to examine breeding in adult females. The whole sample comprised 3863 females and 1468 males. Estimates of size (carapace length) at the onset of sexual maturity were 7.0 mm and 7.8 mm for males and females, respectively. Higher percentage of females bearing ripe gonads was observed during spring and summer over the course of the study, contrasting to the low proportion in fall 1998 and winter 1999. Juvenile shrimps were sampled year-round. These results suggest a continuous reproductive pattern for R. constrictus. Mating, spawning, and juvenile recruitment took place mostly in shallow waters up to 20-m depths in the study region. Warm to mild temperatures may favour the spawning pattern observed in this species. The classical paradigm of continuous reproduction at lower latitudes, with increased seasonality of breeding period at higher latitudes, seems to apply to this species.

Reproduction and recruitment of the South American red shrimp, Pleoticus muelleri (Crustacea : Solenoceridae), from the Southeastern coast of Brazil

Abstract Critical stock conditions for shrimps commonly exploited in southeastern Brazil have resulted in the targeting of other shrimp species such as Pleoticus muelleri. Descriptions of reproductive biology in penaeid species are essential to implement sustainable fishery techniques. Therefore, reproduction, recruitment, and size at sexual maturity of the shrimp P. muelleri were investigated off the coast of the state of São Paulo (23°S), Brazil, from January 1998 through June 2003. Ovarian maturity was used to examine breeding in adult females. Recruitment was defined as the number of juveniles caught per standard trawl (CPUE) in each month and season of sampling. The entire sample comprised 8375 females and 3829 males. Sizes (carapace length) at onset of sexual maturity were 9.1 and 11.1 mm for males and females, respectively. Over 5.5 years, females with ripe gonads were found in every season, with the highest percentages from October to March (spring to summer). Juvenile shrimp occurred year-round. These findings suggest a continuous reproductive pattern for P. muelleri, with temperature as an environmental stimulus for the ovary development cycle. These data and the hypothesis of the intrusion of the South Atlantic Central Water mass, which lowers water temperature and raises plankton production, suggest that the main reproductive months extend from late spring to early summer. The classical paradigm of continuous reproduction at lower latitudes, with increased seasonality of breeding period at higher latitudes, seems to be followed by this species.

The Megalopa and Juvenile Development of Pachygrapsus Transversus (Gibbes, 1850) (Decapoda, Brachyura) Compared With Other Grapsid Crabs

Megalopae were reared in the laboratory to the 7th crab stage. The megalopa and 1st crab stage are described and juvenile development was studied with emphasis on pleopodal differentiation. The megalopal phase, is easily identified, and shares with those of other Grapsinae and Plagusiinae big size, the presence of many natatory setae, and a series of conspicuous teeth on the inner margin of the dactyli from the 2nd to 4th walking leg. These features are regarded as adaptive for settlement in a wave-swept environment, such as the rocky marine intertidal where most of those species live. Fast development of juvenile pleopods is another characteristic of these subfamilies. In Pachygrapsus transversus, the sexes can be distinguished from the 2nd crab stage. Gonopod differentiation in males and the basic segmentation of all four pleopod pairs in females are already concluded at the 5th instar. A review of the available information indicated that settlement of large megalopae and fast juvenile development, preceding a precocious sexual maturity, are trends in Grapsinae and Plagusiinae. On the other hand, the Sesarminae pass through a more extensive juvenile instar sequence and presumably a delayed maturity.