No abstract

Size at morphological sexual maturity, sex-ratio, and the seasonal variation in abundance of the shrimp Artemesia longinaris Bate, 1888 were assessed off Pinheira Beach, Palhoça, Santa Catarina southern Brazil. Shrimp were collected monthly from November 2003 through to October 2004, in two areas that are customarily used by local traditional fishermen (27852 0 -27851 0 S and 48833 0 -48829 0 W). Of the total of 1099 specimens measured, 23.93% were males and 76.07% females. Mean size at first maturity (LM 50 ) was estimated as 56.38 mm total length (TL) for males, and 70.34 mm TL for females. Females were significantly larger than males. Abundance of juveniles varied seasonally. A high predominance of juveniles in the areas sampled occurred in winter for both sexes, and in spring for females. In the summer and autumn, we observed a decrease in juveniles in both areas, mainly, area II. We suggest that the differential migration pattern of sexes during the reproductive cycle was the principal reason for the larger catch of females. The classical paradigm of continuous reproduction at lower latitude, with increased seasonality of the breeding period at higher latitudes, seems to apply to this species.

Gari soLida (Gray, 1828), Semele solida (Gray, 1828) and Protothaca thaca (Molina, 1782) are dominant members of the shallow-water, soft-bottom communities of the Peruvian-Chilean upwelling system. They are exploited commercially all over their distribution range. Reproduction, growth, mortality, and production of these species were studied from a small bay in Chile at 36" S. Total mortality was estimated as 0.842 (G. solida), 0.924 (S. solida) and 0.584 yr-' (P thaca). The influence of latitudinal gradients on reproductive strategies is related to the results on reproduction cycles. Production and mortality estimates are discussed in relation to the influence of the fishery.

RESUMOO desenvolvimento e domínio das técnicas de aquicultura têm levado a intensificação na criação de diferentes espécies, existindo uma tendência de incremento na concentração de compostos nitrogenados nos sistemas de cultivo. Os compostos nitrogenados ocorrem naturalmente no meio aquoso, podendo provocar mortalidade ou afetar o crescimento dos organismos criados. As formas nitrogenadas mais abundantes nos viveiros são a amônia, nitrito e nitrato. Juvenis de camarão-rosa, Farfantepenaeus brasiliensis, foram expostos a diferentes concentrações de amônia, nitrito e nitrato em ensaios de curta duração. Os valores de concentração letal (CL50) para amônia, nitrito e nitrato para 24h a 96h foram respectivamente 24,77 a 8,81mg/L; 252,04 a 105,97mg/L; 1882,63 a 912,07mg/L. De acordo com os resultados obtidos foi possível estimar o nível de segurança de amônia, nitrito e nitrato para juvenis de camarão-rosa em 0,88mg/L, 10,60 e 91,21mg/L, respectivamente.PALAVRAS CHAVE: Amônia, Nitrito, Nitrato, Farfantepenaeus brasiliensis. ABSTRACT Acute toxicity of ammonia, nitrite and nitrate on pink-shrimp juvenile Farfantepenaeus brasiliensis(Latreille, 1817) (Crustacea: Decapoda). The development of new techniques has led to the intensification of aquaculture regarded to rearing of different species. Therefore, there is a tendency to increase the generation of nitrogen compounds in these cropping systems. The nitrogen compounds naturally occur in the water of rearing systems, and may cause death or affect the individual growth. The most abundant nitrogen forms in the ponds are ammonia, nitrite and nitrate. The juveniles of pink-shrimp, Farfantepenaeus brasiliensis were exposed to different concentrations of ammonia, nitrite and nitrate. The LC50 values for ammonia, nitrite and nitrate for 24h to 96h are respectively 24.77 to 8.81mg/L, 252.04 to 105.97mg/L, 1882.63 to 912.07mg/L, respectively. The safe level of ammonia, nitrite and nitrate to pink shrimp juveniles estimated were 0.88mg/L, 10.60 and 91.21mg/L, respectively.

RESUMOO camarão-sete-barbas (Xiphopenaeus kroyeri (Heller, 1862)), pertence à superfamília Penaeoidea, família Penaeidae. Apresenta ampla distribuição geográfica no Atlântico Ocidental, ocorrendo da Carolina do Norte (EUA) ao Estado do Rio Grande do Sul. O presente estudo foi motivado pela necessidade de um melhor conhecimento da biologia e do ciclo de vida do camarão-sete-barbas na Baía de Tijucas, Tijucas, Santa Catarina. O crescimento foi avaliado, para ambos os sexos, através da estrutura das distribuições de freqüência de comprimento, utilizando o modelo de BERTALANFFY (1938), o qual foi aplicado nas amostras oriundas da frota artesanal de arrasto. As equações de crescimento obtidas foram: CC = 31 (1 -e (-0,0072 (t)) ) (fêmeas) e CC = 28 (1 -e (-0,0082 (t)) ) (machos). Os machos apresentaram menor longevidade (561 dias), maior coeficiente de crescimento (0,0082) e menor comprimento assintótico (28 mm), enquanto as fêmeas crescem mais lentamente (0,0072), vivem por um período mais longo (641 dias) e atingem maiores comprimentos assintóticos (31 mm). PALAVRAS CHAVE: Xiphopenaeus kroyeri, crescimento, Tijucas ABSTRACT Growth of sea-bob-shrimp (Xiphopenaeus kroyeri (Heller 1862)), in Tijucas Bay, Tijucas, SC (Brazil).The Sea-bob-shrimp, Xiphopenaeus kroyeri (Heller, 1862), is widely distributed throughout the Western Atlantic, occurring from North Carolina (USA) to Rio Grande do Sul State (Brazil). The study was accomplished in Tijucas Bay, Tijucas, Santa Catarina State with the objective of contributed with the knowledge of biology and life cycle of the species. Samples were obtained from trawl net artisanal fishery. Growth was estimated, for both sexes, through modal progression analysis (MPA), by using the Bertalanffy growth model. The growth equations obtained were: CL = 31(1-e (-0.0072(t-t0)) ) (female) and CL = 28(1-e (-0.0082(t-t0)) ) (male). Males presented lower longevity values (561 days), higher growth coefficient (0.0082) and smaller asymptotic length (28 mm) than females. Females presented slow growth (0.0072), longevity of 641 days and asymptotic length of 31 mm.