Reproductive output of Uca vocator (Herbst, 1804) (Brachyura, Ocypodidae) from three subtropical mangroves in Brazil

Crab fecundity is widely known to vary proportionally to female size, but the female's nutritional state also has an important effect on egg production. This study evaluates intraspecific variability of reproductive output by monthly sampling Uca vocator populations from the Itapanhau, Indaia, and Itamambuca mangroves on the southeastern coast of Brazil. The presence of ovigerous crabs, their carapace width (CW) and their number of eggs were recorded. Additionally, the productivity of the mangroves and the content of organic matter of the sediments were analysed in order to estimate food availability in each locality. Size-specific fecundity relationships were obtained for each population and compared among the three populations. Ovigerous females from Itamambuca are the largest and their fecundities are also the highest among the populations studied. These results probably are associated with the favourable environmental conditions in Itamambuca, as this is a young mangrove with a high productivity level.

A comparison of the allometric growth in Uca leptodactyla (Crustacea : Brachyura : Ocypodidae) from two subtropical estuaries

The allometric growth of Uca leptodacyla from two distinct subtropical estuaries on the Brazilian coast was evaluated concerning its growth pattern and size at onset of sexual maturity. Females attained maturity at similar sizes in both sites (4.1 mm of carapace length in Indaia and 4.2 mm in Ubatumirim), while males differed slightly. They reached the size at sexual maturity of 5.3 mm of carapace length in Indaia and 4.6 mm in Ubatumirim. Growth pattern is Usually similar among crabs from distinct Sites while size at sexual maturity is frequently different. However, in the case of U. leptodacyla it did not occur, probably due to the strong habitat similarity and intrinsic features of this species.

Relative growth of Uca burgersi (Crustacea, Ocypodidae) from two mangroves in the southeastern Brazilian coast

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

SEDIMENT PARTICLE SELECTION DURING FEEDING BY FOUR SPECIES of UCA (BRACHYURA, OCYPODIDAE)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

FIRST ZOEAL STAGE and MEGALOPA of UCA (UCA) MARACOANI (DECAPODA: BRACHYURA), WITH COMMENTS on THE LARVAL MORPHOLOGY of SOUTH-AMERICAN SPECIES of OCYPODIDAE

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relative growth and morphological sexual maturity of Uca Cumulanta (Crustacea : Decapoda : Ocypodidae) from a tropical Brazilian mangrove population

The relative growth of the fiddler crab Uca cumulanta was studied, primarily to determine the size at the onset of sexual maturity for a mangrove population in the estuary of the Patitiba River, Paraty, Rio de Janeiro state, Brazil. The evaluation of the morphological sexual maturity of U. cumulanta was performed using the allometric technique. The relationships that most precisely indicated the size at onset of sexual maturity were carapace length (CL) vs propodus length for males and CL vs abdomen width for females. Males and females are mature at 5.25 and 4.75 mm CL, respectively. The remarkable ontogenetic changes observed in the allometric growth of the male major cheliped and the female abdomen, indicate that growth of these structures is closely connected to the timing of sexual maturity. The relative size at onset maturity obtained for this species was 0.68 and this index was compared to that seen in other species in the genus.

Reproductive pattern comparison of Uca thayeri Rathbun, 1900 and U. uruguayensis Nobili, 1901 (Crustacea, Decapoda, Ocypodidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Ciclo reprodutivo do caranguejo violinista Uca rapax (Smith) (Crustacea, Brachyura, Ocypodidae) habitante de um estuário degradado em Paraty, Rio de Janeiro, Brasil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Allometric growth in the fiddler crab Uca thayeri (Brachyura, Ocypodidae) from a subtropical mangrove

The relative growth of U. thayeri was studied for a subtropical mangrove population in the estuary of the Comprido and Escuro rivers, Ubatuba, São Paulo State, Brazil. The evaluation of the morphological sexual maturity of U. thayeri was performed using the allometric technique. Remarkable ontogenetic changes were observed in the allometric growth of the male major cheliped and the female abdomen, indicating that these structures are closely connected to the timing of sexual maturity. For males, the relative-growth analysis of cheliped propodus length rendered an estimate of 13.8 mm of carapace width for the size at onset of sexual maturity. A distinct growth pattern was observed for the abdomen of U. thayeri females. It has a wide puberty size range (from 10.7 to 16.8 mm of CW) compared to other brachyurans previously studied. Thus, the females' abdominal growth can be represented by three growth phases: immature, transitional, and mature. The major cheliped is the fight one in 50% of males. The median length of the male major cheliped did not differ between right- and left-handed crabs.

Comparative population biology of Uca rapax (Smith, 1870) (Brachyura, Ocypodidae) from two subtropical mangrove habitats on the Brazilian coast

The structure of two populations of the fiddler crab Uca rapax in two subtropical mangrove habitats near Ubatuba, State of São Paulo, Brazil were compared. The size - frequency distribution, sex ratio, and recruitment were evaluated. Sampling was performed monthly from April 2001 to March 2002 in the Itamambuca and Ubatumirim habitats. Crabs were caught manually for 15 min by two collectors during low tide. The carapace width of each crab was measured with a digital caliper, and the sex and ovigerous state were recorded. The median size of the carapace width of males was greater than that of females at both sites (P<0.05). The median size of the crabs from Itamambuca was larger than at Ubatumirim (P<0.05). Only 28 ovigerous females were obtained from both mangroves, which suggested that females might remain in their burrows during the incubation period. The highest recruitment pulse occurred in winter for both populations, probably as a consequence of high reproductive activity during summer. The sex ratio in the size classes showed an anomalous pattern, with a higher frequency of females in the intermediate size classes. This may be related to a greater energy requirement for reproduction in females, thus delaying growth. The variable environmental conditions to which Uca rapax populations are subject appear to act directly or indirectly on the population, causing variations in growth and reproductive processes in the different populations investigated here.

Growth and juvenile development of Uca maracoani Latreille 1802-1803 in laboratory conditions (Crustacea, Decapoda, Brachyura, Ocypodidae).

The life cycle of decapod crustaceans can be classified into three distinct morphological phases: larval, juvenile and adult. Despite its recognized importance, studies of the juvenile phase have been neglected. The present Study aimed to analyze the growth of juveniles from a single population of Uca maracoani under laboratory conditions, and also to describe the morphological differentiation of pleopods in each sex. Megalopae and juvenile crabs or U. maracoani obtained on a Mud beach at Jabaquara, Paraty, on the southern coast of the state of Rio de Janeiro (Brazil), were reared in the laboratory. The specimens were checked daily for molts and deaths. The carapace widths (CW) of intact exuviae and dead individuals were measured under a stereoscopic microscope provided with a micrometer rule. These data allowed the definition of a growth equation as well as the stages related to the beginning of pleopod development, which begins when females reach 3.0 mill CW (6th juvenile developmental stage), similar to the sizes reported for other species of the genus. In males, however, pleopods appear when the crabs reach 3.5 mm CW, equivalent to the 7th developmental stage. This difference may be related to differential growth between sexes. It also may be a consequence of laboratory rearing, or may represent an actual feature of the species.

Comparison of the population structure of the fiddler crab Uca vocator (Herbst, 1804) from three subtropical mangrove forests

The population structure of U. vocator was investigated during a one-year period in three mangrove forests in southeast Brazil. The study specifically addressed comparisons on individual size juvenile recruitment and sex-ratio. The structure of the mangrove forests, i.e. density, basal area, and diameter, and the physical properties of sediments. i.e. texture and organic matter contents, were also examined. A catch-per-unit-effort (CPUE) technique was used to sample the crab populations using 15-min sampling periods by two people. Males always outnumbered females, probably due to ecological and behavioural attributes of these crabs. The median size of fiddler crabs differed among the sampled populations. The mangroves at Indaiá and Itamambuca showed higher productivity than those at Itapanhaú, where oil spills impacting the shore were reported. Marked differences were found regarding individual size, either their size at the onset of sexual maturity or their asymptotic size, suggesting that food availability may be favouring growth in the studied populations.

Physiologic sexual maturity of the fiddler crab Uca rapax (Smith, 1870) (crustacea, ocypodidae) from two mangroves in Ubatuba, Brazil

The gonad development of Uca rapax was studied to achieve the size at onset of its sexual maturity. Crabs were sampled from April/2001 to March/2002 in the Itamambuca and Ubatumirim mangroves in Ubatuba, São Paulo, Brazil. The specimens were grouped in 10 size classes. Juveniles and adult crabs frequencies were assessed for each class. The size of carapace width in which 50% of males and females were considered mature was 14.8 and 12.1 mm (Itamambuca) and 13.6 and 11.4 mm (Ubatumirim), respectively for males and females. Males matured at higher sizes than females, probably due to a major investment in their somatic growth, while females spend their energy in the reproductive process, saving energy for eggs' production.