Sérgio Schwarz da Rocha

Exotic species of freshwater decapod crustaceans in the state of São Paulo, Brazil: records and possible causes of their introduction

Based on recent surveys of the freshwater decapod fauna, distributional data of five exotic species of freshwater decapod crustaceans for the hydrographic basins of the state of São Paulo are presented, as part of a large initiative for a comprehensive survey of the state’s biodiversity (BIOTA-FAPESP Program). These species are the North American crayfish Procambarus clarkii (Girard) (Cambaridae), the crab Dilocarcinus pagei Stimpson (Trichodactylidae) from the Amazon and Paraguay/lower Paraná River Basins, and the palaemonid shrimps Macrobrachium rosenbergii (De Man), from the Indo-Pacific region, Macrobrachium amazonicum (Heller) and Macrobrachium jelskii (Miers), both from the Orinoco, Amazon and the Paraguay/lower Paraná River Basins. Possible modes by which their introduction might have occurred are commented upon and potential consequences are discussed.

ESTIMATING THE POPULATION SIZE OF AEGLA FRANCA (DECAPODA: ANOMURA: AEGLIDAE) BY MARK-RECAPTURE TECHNIQUE FROM AN ISOLATED SECTION OF BARRO PRETO STREAM, COUNTY OF CLARAVAL, STATE OF MINAS GERAIS, SOUTHEASTERN BRAZIL

Abstract The Schumacher-Eschmeyer and the Schnabel estimators for closed population were employed to estimate the population size of Aegla franca from an isolated section (30 m long; area: 76.125 m2) of the Barro Preto stream (20°18′47″S; 47°16′37″W) in the summer and winter seasons of the year 2005. These methods involve mark-recapture technique with multiple sampling, and each season estimate was conducted for eight consecutive days. The study area was isolated with a 4 mm mesh net to prevent migration of aeglids into or out of the study area. Traps were randomly set overnight and inspected for captured aeglids in the following morning. Two marking techniques were employed separately: a mixture of silver purpurin powder and fast-drying glue gel (summer estimate) and cauterization by red-hot pin head (winter estimate). All unmarked individuals from each sampling event were sexed, had their carapace length measured and were then marked, and released back in midpoint of the isolated area of the stream along with previously marked (recaptured) specimens. The Schumacher-Eschmeyer estimator provided very close results between the summer (N = 212 and density = 2.8 ind./m2) and the winter (N = 218 and density = 2.9 ind./m2) estimates. The Schnabel estimate results were also very similar to that obtained by the Schumacher-Eschmeyer method for each corresponding season of the year. Regardless of the marking technique employed, the results obtained and field observations from each estimate indicate that none of the assumptions required by both methods were violated. After subtracting the percentage of immature specimens, the projected overall population size of mature Aegla franca for the whole extension of Barro Preto stream varied from approximately 33,200 in the summer and 29,500 adults in the winter (Schumacher-Eschmeyer estimator) for an estimated area of occupancy equivalent to 0.0125 km2.

Crustáceos decápodes de água doce com ocorrência no Vale do Ribeira de Iguape e rios costeiros adjacentes, São Paulo, Brasil

This paper contributes to the knowledge of the species richness and distribution of decapod crustaceans at the Ribeira de Iguape river basin, south of Sao Paulo State, Brazil. Seven protected areas (E.E. Jureia-Itatins, P.E. Ilha do Cardoso, P.E. Jacupiranga, P.E. Campina do Encantado, P.E. Carlos Botelho, P.E. Intervales and PETAR) were investigated, covering most of the Mata Atlântica remaining in the Ribeira de Iguape basin. Samples were taken during each season of the years 2000 and 2001 using two sampling methods (sieves and traps). Six species of palaemonid shrimps, three atyid shrimps, five aeglid anomuran crabs, and three trichodactylid and one grapsid crabs were collected.

Reproductive Biology in Females of Aegla Strinatii (Decapoda: Anomura: Aeglidae)

Abstract Females of Aegla strinatii (n  =  466) were sampled monthly (September 2003 to September 2005) by means of sieves and traps from Rio das Ostras (24°38′16.2″S; 48°24′05.2″W), at Jacupiranga State Park, South of São Paulo State, Brazil. The reproductive period was markedly seasonal (from May to September) encompassing the Austral late autumn through late winter. This is in accordance to the pattern of reproductive period variations in relation to the latitudinal climate variability verified in species of Aegla. The proportion of adult females exhibiting the ovigerous condition was higher in young/small specimens as compared to old/large ones, and suggests the occurrence of senescence in the latter group. Average size at the onset of functional maturity in females was estimated as 16.66 mm of carapace length (rostrum excluded). The number of eggs per ovigerous females ranged from 1 to 325. Eggs are slightly elliptical and average size varied according to embryonic stage. Mean (± standard deviation) carapace length of juveniles (n  =  118) was 1.50 ± 0.05mm (range: 1.40-1.65mm).

Relative growth, sexual dimorphism and morphometric maturity of Trichodactylus fluviatilis (Decapoda: Brachyura: Trichodactylidae) from Santa Terezinha, Bahia, Brazil

Freshwater crabs are important elements in the aquatic biota of brooks, rivers, lakes and ponds, from both ecological and the socio-economic aspects. Trichodactylidae comprises 51 endemic species from the Neotropical region. Among all the species of this family, Trichodactylus fluviatilis Latreille, 1828 has the widest geographic distribution throughout Brazil. Despite that, there are few published contributions on the biology of this species. The present study investigated the following aspects of T. fluviatilis: relative growth, mean size at onset of morphometric maturity, sexual dimorphism, laterality and heterochely. Specimens were collected monthly from September 2010 through August 2011, from the Velha Eugenia Brook, municipality of Santa Teresinha, State of Bahia. Carapace width (CW), carapace length (CL), major cheliped length (MaCL) and minor cheliped length (MiCL), major cheliped height (MaCH) and minor cheliped height (MiCH), and width of the fifth abdominal segment (5AB) were measured to evaluate the presence of sexual dimorphism; the major difference between the sexes was in the CW vs. 5AB ratio. Heterochely was observed in males and females,with the right cheliped larger than the left in 89% of males and 81% of females. Crab size at the onset of morphometric maturity (= puberty molt) was estimated based on the ratio between CL, cheliped dimensions, 5AB and CW (independent variable). Females were larger than males when they reached morphometric maturity in all studied relations. We recommend the use of chelipeds and abdominal width relationships to estimate the size at the morphometric maturity in males and females, respectively.

Length-weight relationship and condition factor of Macrobrachium amazonicum (Heller, 1862) (Decapoda, Palaemonidae) from a reservoir in Bahia, Brazil

Macrobrachium amazonicum (Heller, 1862) is a freshwater prawn occurring in rivers and reservoirs of Central and South America. Given its broad geographical distribution, the species shows great intraspecific morphological, reproductive, physiological and ecological plasticity. Furthermore, it also stands out for its economic importance, especially in the states of North (Para and Amapa) and Northeast Brazil. Despite the wide geographic distribution and economic importance of M. amazonicum, the biology of this species is poorly known, particularly in Northeast Brazil. We analyzed the length-weight relationships and condition factor of males and females of M. amazonicum. Specimens were collected monthly from September 2008 to August 2009 at the Pedra do Cavalo Reservoir, city of Cabaceiras do Paraguacu, State of Bahia. All specimens were sexed, measured and weighted. After that, length-weight relationships and the allometric (K) and relative (Kr) condition factors were calculated. Altogether 2,974 specimens were analyzed, 334 of which were males (11%) and 2,640 were females (89%). Females were larger and heavier than males. Males and females showed isometric and negative allometric growth, respectively. Monthly variations in the condition factor were similar for both sexes, and correlated strongly with rainfall regime and temperature in the region. Such variations are not correlated with the reproductive cycle of the species, but are probably correlated with food availability and somatic growth.

Extension of the known distribution of Aegla strinatii Türkay, 1972 and a checklist of decapod crustaceans (Aeglidae, Palaemonidae and Trichodactylidae) from the Jacupiranga State Park, South of São Paulo State, Brazil

There are over 120 species of freshwater decapod crustaceans in Brazil. This paper contributes to the knowledge of the species richness and distribution of decapod crustaceans from Jacupiranga State Park, South of Sao Paulo State. The main objectives were to investigate the geographical distribution of A. strinatii and to generate a checklist of the decapod species collected from the sampling sites. Sixteen sampling sites were investigated during the year of 2007 and four species were collected. The present report represents a new record of A. strinatii from Sao Paulo State and adds three more localities at Jacupiranga State Park where the occurrence of T. fluviatilis is confirmed.

REPRODUCTIVE BIOLOGY AND POPULATION STRUCTURE OF POTIMIRIM BRASILIANA VILLALOBOS, 1959 (DECAPODA, ATYIDAE) FROM A LITTORAL FAST-FLOWING STREAM, SAO PAULO STATE, BRAZIL

The importance of decapod crustaceans has induced scientific studies in various fields of biology. Therefore, structure, reproductive biology and fecundity of a population of Potimirim brasiliana Villalobos, 1959 from Jureia-Itatins Ecological Station in Peruibe, State of Sao Paulo, were studied. Shrimps were captured at 4-month intervals from spring 2000 to summer 2001. Overall sex ratio was skewed towards males (2.2 males : 1 female). Mean ± S.D. total body length was 17.1 ± 2.1 mm (or 4.8 mm carapace length (CL)) for females and 14.0 ± 1.4 mm (or 3.6 mm CL) for males. Ovigerous females comprised 55.4% of all females collected and were present in all samples and at higher proportions in the spring and the summer. The size at onset of maturity (= smallest ovigerous female) was 13.3 mm (CL = 3.7 mm). Fecundity ranged from 171 to 749 eggs (mean ± S.D. = 361.5 ± 119.5 eggs) per female. In addition, there was a positive correlation between the number of eggs and the carapace length of ovigerous females according to the equation NE = 197.99CL − 520.75. Mean ± S.D. size and volume of eggs was 520.1 ± 32.5 × 309.1 ± 17.8 μm and 0.038 ± 0.006 mm3 (early eggs) and 534.2 ± 15.8 × 324.4 ± 12.6 μm and 0.042 ± 0.003 mm3 (late eggs). The increment in size during the embryonic development was marginally significant for the minor axis ( U = 3 ; p < 0 . 047 ), not significant for the major axis ( U = 5 ; p = 0 . 117 ) and significant for volume ( U = 840 ; p = 0 . 0009 ). Compiled data on the reproductive pattern reported for Potimirim Holthuis, 1954 species from Brazil revealed that temporal variation of reproductive activity and fecundity are influenced by environmental limiting factors correlated with latitude.

Diferença entre dois métodos de coleta utilizados na captura de crustáceos decápodes em um rio da Estação Ecológica Juréia-Itatins, São Paulo

Sampling collections were taken quarterly from Fall 2000 to Summer 2001 at Jureia-Itatins Ecological Station using two different sampling methods (hand sieve and traps). Comparing both sampling methods one can verify differences in faunal composition, richness, degree of dominance, evenness and size and number of individuals. Moreover, the sex ratio of Macrobrachium acanthurus (Wiegmann, 1836) may differ according to the sampling method. Decapod crustaceans are known to inhabit a great variety of habitats and niches, therefore to obtain an effective qualitative and/or quantitative sampling, in which the majority of decapod species are collected, the use of more than one sampling method is recommended.

Minutes of the Assembly of the Brazilian Crustacean Society

(SSR) Presidente da Sociedade Brasileira de Carcinologia, Universidade Federal do Reconcavo da Bahia – UFRB, Centro de Ciencias Agrarias, Ambientais e Biologicas – CCAAB, Campus Universitario, Rua Rui Barbosa, no 710, Bairro Centro, CEP: 44380-000, Cruz das Almas, BA, Brasil. Email: presidentesbc@gmail.com (CRMS) Chair Man of VII CBC; Museu Paraense Emilio Goeldi, MPEG, Belem, PA, Brasil. Email: crsantos@museu-goeldi.br (FLM) The Crustacean Society – TCS Latin American Liason; Vice President of Asociacion LatinoAmericana de Carcinologia – ALCARCINUS. Departamento de Biologia, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto (FFCLRP), Universidade d Sao Paulo (USP), Av. Bandeirantes 3900, 14040-901, Ribeirao Preto, SP, Brasil. Email: flmantel@usp.br