Carmen Lúcia Del Bianco Rossi-Wongtschowski

Demersal fish community on the inner shelf of Ubatuba, southeastern Brazil

Fluctuations in the distribution and abundance of demersal fishes collected by otter trawl on the continental shelf of Ubatuba were examined over a two-year sampling period, in an area up to 50 m depth. A total of 111 species were collected. Seasonal and annual fluctuations in species abundance were related to differences in the distribution of Coastal Water and South Atlantic Central Water masses. The demersal fish fauna in the area was divided into three ecologically distinct communities: Tropical Sciaenid, Subtropical Sciaenid, and Gerreid-Haemulid. The most important one is the Tropical Sciaenid Community, characterized by Ctenosciaena gracilicirrhus, Paralonchurus brasiliensis, and Cynoscion jamaicensis.

Estudo das variações da relação peso total/comprimento total em função do ciclo reprodutivo e comportamento, de Sardinella brasiliensis (Steindachner, 1879) da costa do Brasil entre 23ºS e 28ºS

This paper analyses some aspects on the length/weight relation ship of Sardinella brasiliensis and its variations as a function of their reproductive cycle and displacements along the Brazilian coast between 23oS and 28oS. The area surveyed was divided into five sub-areas, each one covering one degree of latitude. The relationship and its variations between shoals were studied for each sub-area at different seasons and for the sub-areas at the same season. The absence of a variation pattern for the length/weight relationship has shown to be the result of seasonal changes in the physiological aspects of fish (as a function of their reproductive cycle) as well as result of behaviour of individuals in two main areas: 23oS-25oS and 26oS-28oS, which are spawning areas, spawning occuring during spring and summer at the first and only during spring at the latter. After spawning the young (from both areas) more at different times to a common trophic area where they find suitable conditions (25oS26oS), returning to their original sub-areas at different occasions, following their first sexual maturation. Although spawning takes place at different times and sites, with the convergence of young to a common nursery, mixing might occur. Further studies on meristics and body proportions are being developed regarding the existence of different populations.

Demersal fish assemblages off São Sebastião, southeastern Brazil: structure and environmental conditioning factors (summer 1994)

The demersal fish community of the Channel and shelf of Sao Sebastiao (SP), on the southeastern Brazilian coast, was investigated during the summer of 1994. The sampling was carried out usinga bottom otter trawl at 26 stations located between 8 m and 65 m in depth. Ninety-three species of 40 families were identified in the area. Sciaenids were the most prominent in number of species, abundance, and weight. Ctenosciaena gracilicirrhus, Paralonchurus, brasiliensis, and Cynoscion jamaicensis dominated in the catches. Cluster analysis showed three major groups of species and three groups of sites. The first group was composed of species found in the Channel and shallower areas of the inner shelf, the second of species associated with the inner shelf «50 m depth), and the third group of species fTom the outer shelf (> 50 m depth). Environrnental variables considered in Canonical Correspondence Analysis (CCA) explained 51 % of the variation in the species data. Bottom water temperature was the most important variable selected by CCA, accounting for 21% of the explainable variance. The results revealed that structure of the ichthyofauna was associated with water mass distribution. During the period studied, the area was occupied by the warm Coastal Water (CW), but cold South Atlantic Central Water (SACW) was detected over the bottom or the outer shelf, influencing the distribution and abundance ofthe main species.

Throphic groups of demersal fish community from the continental shelf, Ubatuba, Brazil: I. Chrondrichthyes

Stomach contents of seven cartilaginous fish species were analysed with the aim to detect trophic groups. Sampling was effectuated between October/85 and July/87 off the coast of Ubatuba (Sao Paulo, Brazil) in waters up 50 m depth. The relative importance of different components of the diet was expressed as a percentage frequency of occurrence and percentage number. The seven species were grouped in: fish feeders - Squalus cubensis; benthonic crustacean and fish feeders - Raja castelnaui, Raja cyclophora, Raja agassizi; benthonic invertebrate feeders - Rhinobatos horkelii, Zapteryx brevirostris, Psammobatis glansdissimilis.

Age and growth of the Argentine hake Merluccius hubbsi Marini, 1933 in the Brazilian South-Southeast Region during 1996-2001

This is the first detailed study on the age and growth of the Argentine hake Merluccius hubbsi in Brazilian waters. A total of 3,651 specimens obtained from surveys and sampling landings using trawlers and long-lines in the South-Southeast Region (21oS to 34oS) between 1996 and 2001 were analyzed. Readings of sliced and burned otoliths were conducted on 686 individuals (397 females, 129 males and 160 young - sex not identified), identifying opaque and translucent zones. Marginal increment and edge type percentage methods were used for validation, resulting in one ring per year, formed during summer-autumn. Fish with no more than eight rings and six years of age were found, the two first rings after the core being formed during the first year. Back-calculation methods were applied to length/age data and the parameters of von Bertalanffys growth model were fitted based on average length per ring. The value of maximum theoretical length varied between 470.27 mm and 807.40 mm; growth coefficient varied from 0.1657 to 0.3555 year-1 and the theoretical age at length zero between -1.2846 and -0.4552 years. Growth of females and males differed significantly. The techniques applied and the results obtained are discussed and compared with studies on hake conducted in Uruguay and Argentina, providing important information for the management of the species in Brazil, where it presents clear signs of overexploitation.

Grupos tróficos de peixes demersais da plataforma continental interna de Ubatuba, Brasil: I. Chondrichthyes

Com o objetivo de detectar grupos troficos, foram analisadas amostras de conteudos estomacais de sete especies de peixes cartilaginosos. Os exemplares foram coletados no periodo de Outubro/85 a Julho/87 na plataforma interna de Ubatuba, SP, Brasil (da costa, ate a isobata de 50 m). A importância dos itens alimentares foi analisada atraves da frequencia numerica (FN) e da frequencia de ocorrencia (FO). As especies foram agrupadas em tres grupos distintos: Piscivoros: Squalus cubensis; comedores de peixes e crustaceos bentonicos: Raja castelnaui, Raja cyclophora, Raja agassizi; comedores de invertebrados bentonicos: Psammobatis glansdissimilis, Rhinobatos horkelii, Zapteryx brevirostris.

Merluccius hubbsi (Teleostei: Merlucciidae): stock identification based on reproductive biology in the south-southeast brazilian region

A merluza Merluccius hubbsi, especie demerso-pelagica distribuida desde o Rio de Janeiro, Brasil, ate a Terra do Fogo, Argentina, tornou-se alvo das frotas de arrasto de fundo da regiao Sudeste-Sul do Brasil desde 2001. Estudos anteriores sobre a biologia da especie sugeriram a existencia de mais de um estoque em aguas brasileiras, relacionados a caracteristicas ambientais. Para verificar esta hipotese, exemplares oriundos de quatro areas em aguas brasileiras foram coletados durante o verao e o inverno nos periodos 1996-2001 e 2004, sendo as femeas utilizadas para analisar variacoes espaco-temporais na maturacao gonadal. Para corroborar estas analises tambem foram aplicados indices gonadais. Os resultados mostraram a ocorrencia de um gradiente norte-sul para a desova, que e mais intenso no verao em 21°S e no inverno em 34°S. Foram identificados dois estoques: um denominado Sudeste, que se distribui entre 21°S-29°S, e outro Sul, entre 29°S-34°S, este ultimo compartilhado com o Uruguai e a Argentina. Os estoques brasileiros apresentam sinais de sobrepesca, situacao que merece atencao e medidas apropriadas de gestao.

Estudos sobre estrutura, ciclo de vida e comportamento de Sardinella brasiliensis (Steindachner, 1879), na área entre 22ºs e 28ºs, Brasil: 1. morfologia dos otólitos

O presente trabalho apresenta os resultados obtidos na analise de 4.751 pares de otolitos de Sardinella brasiliensis coletada na area entre 22oS (RJ) e 28oS (SC), com a finalidade de serem utilizadas, estas estruturas, na leitura do numero de aneis, e como fonte de subsidios adicionais a caracterizacao de populacoes. A estrutura dos otolitos e descrita e as principais dificuldades na interpretacao dos aneis sao discutidas, mostrando-se que ocorrem aneis nao periodicos (TR e TPN), relacionados a eventos ocorridos durante as fases larval e pre-juvenil, e aneis de crescimento bem definidos, que se constituem em indicadores da idade individual. Caracteristicas morfologicas e morfometricas, principalmente comprimentos no rostro e no anti-rostro e peso dos otolitos em relacao ao comprimento total do peixe, corroboram indicacoes anteriores de que a especie nao homogenea em sua area de ocorrencia, auxiliando na identificacao de grupos distintos. As distribuicoes espacial e temporal de otolitos de S. brasiliensis, apresentando caracteristicas diversas, sugerem haver migracoes e mistura de individuos dos diferentes grupos.

Threatened fishes of the world: Merluccius hubbsi Marini, 1933 (Merlucciidae)

Common name: Argentine hake. Conservation status: Overexploited (Aubone et al. 2004; Vaz-dos-Santos and Rossi-Wongtschowski 2005; Sao Paulo State Red List—DOE Decree No 53.494/2008). Identification: Opercle upper margin parallel to the lateral line, first branchial arch 12–16 gill rakers, second dorsal fin 30–40 rays, anal fin 36–41 rays, body 120–144 lateral scales rows scales (Inada 1981; Cohen et al. 1990; Lloris et al. 2005). Distribution: Southwestern Atlantic from Brazil (21S) to Argentina (55S) (Figueiredo and Menezes (1978); Lloris et al. 2005). Abundance: Brazilian 2001–2002 (21S–34S) winter-spring and summer bottom trawl surveys: 19,497 and 21 934 tons biomass, respectively (Haimovici et al. 2008); Uruguayan-Argentinean (34S–49S) 1998’s surveys revealed 1 320 038 tons of biomass (Aubone et al. 2004). Habitat: Benthopelagic mainly in continental shelf and slope cold waters (7–23°C) (Cohen et al. 1990). Size and growth: 900 mm; 12–13 years; females remain older and larger than males (Lorenzo 2003; Bezzi et al. 2004; Vaz-dos-Santos and RossiWongtschowski 2007). Reproduction: Multiple spawner; north-south spawning gradient: springsummer (21S), winter (34S–38S) and spring– summer (43S–47S) (Bezzi et al. 2004; Honji et al. 2006; Vaz-dos-Santos et al. 2009a). This pattern Environ Biol Fish (2010) 87:349–350 DOI 10.1007/s10641-010-9608-y

Length-weight relationships of the ichthyofauna associated with the Brazilian sardine, Sardinella brasiliensis, on the Southeastern Brazilian Bight (22°S-29°S) between 2008 and 2010

In this study, estimates of length-weight relationships are presented for twenty-four species caught in association with the Brazilian sardine, Sardinella brasiliensis, during four acoustics surveys carried out under the Program ECOSAR (Prospecting and evaluation of biomass of the stock of Brazilian sardine on the southeast coast by acoustic methods), which was to evaluate the biomass of species that were caught. The model parameters were estimated with the nonlinear iterative method of least squares. The value of the coefficient of determination (r2) and residual analysis were employed to verify the appropriateness of fit. The coefficient b values were tested with respect to isometry (β=3) using a tα1,0.05 test. The values of coefficient b ranged from 2.377 to 3.538. There is a tendency for positive allometry (b) in the sampled ichythyocenose.