Abstract Scomberomorus brasiliensis is the most important fish species of the small-scale fishery off the southwestern Atlantic north of the La Plata estuary. For management purposes, this study evaluated their reproductive biology, size, age and growth along the Paraná coast. Monthly samples (March 2018-June 2020) from the fishery comprised 933 specimens (413 males, 520 females), 210-779 mm fork length, corresponding to a size smaller than in the northern areas. It presented negative allometry (b = 2.69159, length-weight relationship). Specimens in all stages of maturity occurred during the study period, indicating spawning in the area from October to June, peaking from January to March. The gonad-length relationship was suitable to confirm this assessment. Individual fecundity varied between 34,484 and 390,786 oocytes. Maturity occurred at L50 = 446.46 mm, t50 = 1.4 years, and L100 = 588.79 mm, and t100 = 2.3 years. The growth parameters were L∞ = 771.68 mm, k = 0.65 year-1 and t0 = -0.102 years, with cohorts aged from 0.5 to 6.5 years. Scomberomorus brasiliensis along the Paraná coast constitutes a self-sustaining group, not directly related to that from northeastern Brazil. This small-scale fishery is not currently negatively affecting stock level; it is essential to monitor these attributes to detect future changes or impacts.

O presente estudo foi realizado no litoral entre a divisa dos Estados do Paraná e Santa Catarina, em duas comunidades pesqueiras artesanais que integram os municípios de Guaratuba (PR) e Itapoá (SC). Foram acompanhadas as atividades pesqueiras das comunidades, entre julho de 2001 e março de 2003, com o objetivo de: listar as espécies de elasmobrânquios capturadas pelas comunidades em questão; avaliar o uso comercial das espécies; observar a ocorrência sazonal das espécies nos desembarques; estimar a freqüência relativa de captura por aparelho de pesca; e inferir sobre a biologia reprodutiva das espécies. Durante o período estudado foram capturados: Carcharhinus falciformis, Galeocerdo cuvier, Rhizoprionodon lalandii, R. porosus, Sphyrna lewini, S. zygaena, Squatina guggenheim, Narcine brasiliensis, Rhinobatos percellens, Zapteryx brevirostris, Rioraja agassizii, Dasyatis americana, D. guttata, D. hipostigma, Gymnura altavela, Myliobatis goodei, Rhinoptera bonasus e R. brasiliensis. Quanto à comercialização das espécies, foi observado que todos os tubarões capturados na área de estudo são comercializados, dentre as raias, apenas Rhinobatos percellens e Zapteryx brevirostris. Nos desembarques, a ocorrência de elasmobrânquios foi maior durante o inverno e a primavera. A maioria das capturas ocorreu com redes de emalhe, o arrasto camaroneiro pouco capturou. Os dados do presente trabalho indicaram a utilização da área estudada para o parto das espécies G. cuvier, R. lalandii, R. porosus, S. lewini, N. brasiliensis e R. agassizii; para o crescimento de todas as espécies amostradas; e para a gestação de R. percellens e Z. brevirostris. É sugerido que medidas que visem a proteger as espécies sejam tomadas, sem trazer prejuízos e conflitos para as comunidades de pescadores.

This study was done in the South coast of Parana State and North coast of Santa Catarina State, Brazil, in two artisanal fishermen communities. Between July, 2001 and March, 2003 the fishing activities were observed aiming to: report the elasmobranchs caught species; report which species are commercialized; observe the seasonal occurrence of the species in the landings; estimate the frequency of capture by different fishing gears; and infer about the reproductive biology of the species. During the studied period were captured: Carcharhinus falciformis, Galeocerdo cuvier, Rhizoprionodon lalandii, R. porosus, Sphyrna lewini, S. zygaena, Squatina guggenheim, Narcine brasiliensis, Rhinobatos percellens, Zapteryx brevirostris, Rioraja agassizii, Dasyatis americana, D. guttata, D. hipostigma, Gymnura altavela, Myliobatis goodei, Rhinoptera bonasus and R. brasiliensis. It was observed that all sharks and only two ray species (R. percellens and Z. brevirostris) are commercialized. In the landings, elasmobranchs were more frequent during winter and spring. Most catches were done by gillnets, while just a few captures were done by shrimp trawls. The data indicated that the studied area is used by G. cuvier, R. lalandii, R. porosus, S. lewini, N. brasiliensis and R. agassizii to give birth; by all species for growing; and during the gestation of R. percellens and Z. brevirostris. It is suggested that actions aiming to protect the species must be taken, without harming and conflicts for the fishermen communities.

Diapterus rhombeus (Cuvier, 1829) is one of the most common Gerreidae species in the estuarine region at the Guaratuba Bay, Southern Brazil. Based on studies developed between July, 1993 and January, 1997, it was observed that its presence in the mangrove area is not regular: the smallest individuais are more abundam during late summer and in autumn, and the largest ones during spring and early summer. Its diet comprises plant material and invertebrates, specially polychaets. The morphological aspects of the gonads, the monthly changes on the Condition Factor, and lhe monthly distribution of the individual size groups, suggest that this population spawns during the spring, out the estuarine region. The smaller individuais use the mangrove area of Guaratuba Bay to a growth phase, and the adulls to make somatic reserves to the spawning period.

The Guaratuba Bay (25o52'S, 48o39'W) is the second largest estuarine system of the State of Parana, Brazil. It extended inside of the continent for about 15 km and is surrounded by mangroves. Water depth can reach up to six meters. The fish faunal composition of this area was evaluated with a bottom trawl and, occasionally, casting and gill nets. One species of Chondrichthyes and 59 of the Actinopterygii (50 genera and 28 families) were reported from the Bay. The results were not significantly different from those of the Paranagua Bay, except by the lower number of species. These differences appear related to distinct collection efforts and the extension of surveyed areas. No species can be considered endemic to the region. Tipically freshwater species were not collected.

Reproductive and biometrical analyses were pertormed on 1629 individuals of P. corvinaeformis collected monthly from October 1993 to September 1996, at Guaratuba Bay, Southern Brazilian coast. The results indicate that the species is more abundant in the mangrove area during winter, when the largest individuais were collected, and spring, when the water temperature is lower and the salinity higher than summer or autumn. The relationship of body weight to body length, for grouped sexes, is "lnTW= -12,0456 + 3,1831 lnTL". The monthly Condition Factor is highest during summer and lowest during winter. It is suggested that P. corvinaeformis is present in the mangrove area during a specific etape of its life cycle and does not use this area to maturation and spawn.

Seasonal variation of food items of Bairdiella ronchus (Cuvier, 1830) classified by size was analysed based on monthly samples between september/1993 and september/1996 at the Guaratuba Bay, Southern Brazil. The stomach contents of a hundred eighty-two fishes were analysed by the Occunence Frequency Method and Point Count for a Lot Method. The individuais were divided in two groups, smaller and longer than 140mm, and a comparative study of digestive tract and branchial are was performed for these groups. For fishes smaller than 140mm the following sequence of items was obtained matching both methods by using the Preponderance índices: decapods (subdivided in Brachyura, Caridea and Penaeidea), polychaets, isopods, fishes, unidentified material, copepods, amphipods, molluscs and plant material. For fishes longer than or equal to 140mm the sequence was decapods, polychaets, fishes, copepods, amphipods, isopods, molluscs and plant material, in this order. These results suggest that Bairdiella ronchus at the Guaratuba Bay is a carnivorous species using mainly decapod crustaceans as food throughout the year.

A total of 1312 individuais of S. rastrifer were sampled from March 1994 to September 1996 at the Guaratuba Bay, Southern Brazilian coast. This species is a permanently inhabitant of the mangrove area throughout the year. The weight/length relationship of the species in the region is "In TW =-12,35 + 3,22 In TL", and the individuais may reach 172mm of total length. The analyses of gonadal morphology and gonadossomatic index indicate that S. rastrifer is a multiple spawner species, that reproduces at the mangrove area during a long period of the year. The reproductive activity is more intense during the winter and mainly the spring, when the value of Condition Factor declines and empty folheies are found in the ovaries.

Seasonal variation of the food items of the "bagre-urutu", Genidens genidens is analysed based on monthly samples between September, 1993 and April, 1995 at the Guaratuba Bay, coast of Paraná. The stomach contents of 105 fish is analysed by the Occurrence Frequency Method and 41 of these have also been analysed by the Volumetric Method. Matching both methods using the Preponderance índices, a larger incidence of decapods is determined, followed by other crustaceans, molluscs, polychaets, fish, and plant material. The data show the existence of a strong seasonal variation in the diet.

Histological changes in the oocyte development of South American lungfish are described. During maturation, pre-vitellogenic and vitellogenic phases could be distinguished, and they are similar to those of teleost fishes.

Based on original and literature data, this study discusses the close relationship that seems to exist between the pre-ovulatory hydratation (POH) on fish oocytes and the marine environment, contrasting with the absence of this process on freshwater species. The difference is mainly explained by the necessity or not of intraoocitary water on eggs flutuation, in one or another situation, according to the surroundings. Once accepted this hipothesis, it is proposed that POH should be an efficient indicator of the adaptation to freshwater environment in fish species originated from marine groups.

Foram descritas histologicamente, em cinco espécies de teleósteos do litoral de São Paulo, as fases ovocitárias envolvidas no processo de maturação ovariana. Verificou-se que o desenvolvimento dos ovócitos é do tipo sincrônico em mais de dois grupos, indicando que elas devem efetuar múltiplas desovas por temporada. Mediante aplicação do método apresentado por Greeley Jr. et al. (1987), identificou-se o tamanho dos ovócitos em cada fase, segundo a espécie. Obtiveram-se, assim, os diâmetros aproximados em que os ovócitos ingressam nos períodos de vitelogênese e de hidratação pré-ovulatória, que foram, respectivamente (em µm): 140 e 580 em Harengula clupeola, 100 e 480 em Urophycis brasiliensis, 140 e 480 em Eucinostomus argenteus, 140 e 640 em Isopisthus parvipinnis, e 100 e 540 em Menticirrhus americanus. Os dados fornecidos podem ser aplicados em trabalhos futuros sobre ciclo de vida dessas espécies, uma vez que, associados a medições em ovócitos, contribuem ao conhecimento do grau de maturação dos exemplares analisados.

The phases of the oocyte involved in the ovarian maturation were histologically described for five teleosts species from São Paulo coast. It was observed that the oocyte development is group-synchronous in more than two batches, suggesting multiple spawnings per season. Using the Greeley Jr. et al method (1987), the oocyte size was obtained in each phase, according to the species. The approximate diameters in which the oocytes enter the vitellogenesis and preovulatory hydration were, respectively (in µm): 140 and 580 in Harengula clupeola, 100 and 480 in Urophycis brasiliensis, 140 and 480 in Eucinostomus argenteus, 140 and 640 in Isopisthus parvipinnis, and 100 and 540 in Menticirrhus americanus. Data presented may contribute for future life cycle studies of these species, by helping the identification of the ovarian maturation level of the considered specimens, using oocyte morphometric measures.

Foi descrita a constituição histológica do esófago, estômago e cecos pilóricos de Semaprochilodus insignis, um Characiforma de expressiva ocorrência na Amazônia central, onde é usualmente conhecido como "jaraqui escama-grossa". As camadas epitelial e muscular mostraram-se bastante variáveis de órgão para órgão, e mesmo em diferentes segmentos de um único órgão. O epitélio do esôfago é inicialmente estratificado pavimentoso e finalmente simples mucoso. O estômago compõe-se de uma porção descendente, revestida por glândulas gástricas, e uma ascendente, não-glandular. A camada muscular nestes dois órgãos sofre substituição gradual da estriada para a lisa, bem como a orientação dos feixes. Os cecos pilóricos, pequenos e numerosos, não apresentam nem componentes glandulares, nem absortivos. Por fim, é sugerido um mecanismo geral para a digestão, considerando o hábito alimentar dessa espécie.

The authors have described the histological strusture of oesophagus, stomach and pyloric caeca from Semaprochilodus insignis, on ilyphagus freshwater fish from the central Amazon.The oesophagus presents in the first portion a stratified, non glandular epithelium and in the second portion a colwnnar one, with mucous secreting cells, wile the stomach shows a descendent portation with glandular mucosa and an ascendent with a very thick wall. The pyloric caeca, very numerous, have unknown function.The digestive tube structure of S. insignis is related to their feeding habit, and hypothesis are propesed about digestion food mechanism.