Morphometry and relative growth of the Brazilian sardine, Sardinella brasiliensis (Steindachner, 1879) in the southeastern Brazilian bight

The Brazilian sardine, Sardinella brasiliensis, is a small pelagic clupeid fish distributed primarily between 22°S and 29°S, where it forms large schools. The species is an important fishery resource and is targeted by purse seine vessels operating in the area. Although an extensive literature addresses various characteristics of the species, studies of its morphometry and relative growth are scarce. The aim of the present study was to analyze the relative growth based on body and otolith morphometry to identify the patterns characterizing the population. Monthly samples were obtained during 1985 and 1987, and data on total length, total weight and otolith length, height and weight were analyzed. The allometric model of Huxley (y = axb) was fitted seasonally and by year, and regressions were compared among seasons and between years. The regression coefficient "b" was tested (t-test) to identify isometry and allometry. A total of 603 sardines, with total lengths ranging from 120 mm to 229 mm, were analyzed. The length-weight relationships tended to show positive allometry, whereas the total length-otolith measurement relationships tended to show negative allometry. The relative growth rates decreased during the year and showed the lowest values during spring in association with the peak of the spawning period. In contrast, the condition factor (coefficient "a" of the allometric regression) increased gradually during the year until spring as a consequence of the increasing weight of the fish due to gonad maturation. Comparisons between the years analyzed also show that the fish grew faster during the collapse of the stock, in 1987. The methodology used in this study allowed the detection of this effect. This study established the historical pattern of relative growth and showed that morphometry and relative growth offer efficient tools for monitoring the sardine in the study area

Relações comprimento-peso da ictiofauna associada à sardinha-verdadeira, Sardinella brasiliensis, na Bacia do Sudeste do Brasil (22ºS‑29ºS) entre 2008 e 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.No presente estudo são apresentadas as estimativas das relações comprimento-peso para vinte e quatro espécies capturadas em associação com a sardinha-verdadeira (Sardinella brasiliensis) durante quatro cruzeiros de prospecção hidroacústica realizados no âmbito do Programa ECOSAR (Prospecção e avaliação de biomassa do estoque de sardinha-verdadeira, na costa sudeste, por métodos hidroacústicos), cujo objetivo foi permitir a avaliação das biomassas das espécies capturadas. Para estimação dos parâmetros dos modelos foi empregado o método iterativo não linear de mínimos quadrados; o valor do coeficiente de determinação (r2) e a análise de resíduos foram empregados para verificar a adequação dos ajustes. Os valores dos coeficientes b foram testados em relação à isometria (β=3) através de teste tα1,0,05. O valor do coeficiente b variou entre 2,377 e 3,538, tendo sido constatada tendência de alometria positiva para o b na ictiocenose amostrada

Checklist of the marine fishes collected during hydroacoustic surveys in the southeastern brazilian bight from 1995 to 2010

The spatial distribution of small pelagic fishes off the Southeastern Brazilian coastal area (22°-29°S) was investigated over six periods, from 1995 to 2010, in the context of the Program "Prospection and Assessment of the Biomass of the Sardine, Sardinella brasiliensis" in order to provide data about their pattern of distribution and biomass. A checklist of the species collected is presented herein with data on geographic position and depth of captures. Such information is intended to be a reference about the fauna that occupied the region in the period under investigation, and allow future comparisons about the resilience of the local fauna, i.e., the detection of future changes caused by environmental factors or human activities. Sampling was conducted during hydroacoustic surveys with mid water trawling plus a few purse seine operations between 10 m and 100 m depth. A total of 86 species were collected

Population dynamics of Scomberomorus brasiliensis from a small-scale fishery off Southern Brazil

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

Desarrollo ontogénico del otolito sagitta de la anchoa, Anchoa tricolor, en un estuario subtropical

In order to characterize the ontogeny of Anchoa tricolor, the morphology and morphometry of sagitta otoliths were described. A total of 397 pairs of sagitta otoliths of A. tricolor (20 to 85 mm) were measured and analysed by means of digital images. Morphological description was done in terms of shape and features. The Huxley model was fitted to otolith length against total length (TL) and weight (TW), and residual analyses were done in order to detect the polyphasic growth. Six shape indices were calculated (otolith height/otolith length and otolith length/total length aspect ratios, rectangularity, roundness, relative sulcus surface and rostrum index) and after size effect removal, they were analysed in terms of TL. The results of these analyses allowed three distinct growth phases to be identified: (1) up to 40 mm TL and related to low swimming ability; (2) between 41 and 60-70 mm TL, when fish displacements increase but the first maturation has not yet occurred; and (3) after 71 mm TL, when fish become adults. Landmarks and semi-landmarks were used to analyse relative warps during the otolith development. The MANOVA analysis between the centroid size and class intervals showed significant differences in the interaction of all classes except between 71-80 and 81-90 mm.Se describen la morfología y morfometría de los otolitos sagitta de Anchoa tricolor con el objetivo de caracterizar su ontogenia. Se midieron un total de 397 pares de otolitos sagitta de A. tricolor (20 a 85 mm) y se analizaron por medio de imágenes digitales. La descripción morfológica se hizo en términos de forma y características. Se ajustó el modelo de Huxley a la relación longitud del otolito, longitud total (TL) y peso (TW), respectivamente, y se realizaron análisis de residuos para detectar el crecimiento polifásico. Se calcularon seis índices de forma (OH/OL y OL/LT radios de aspecto, rectangularidad, redondez, superficie relativa del sulcus e índice de rostrum) y, una vez eliminado el efecto de talla, se analizaron en términos de longitud total. Los resultados de estos análisis permitieron identificar tres fases distintas de crecimiento: (1) una fase inicial, hasta 40 mm TL y relacionada con una habilidad natatoria baja; (2) entre 41 y 60-70 mm TL, cuando los desplazamientos del pez aumentan, pero aún no se ha producido la primera madurez y (3) superior a 71 mm TL, cuando el pez es ya adulto. Se utilizaron puntos homólogos y puntos equidistantes para analizar deformaciones relativas durante el desarrollo del otolito. El análisis MANOVA entre el tamaño del centroide y los intervalos de clases de talla mostraron diferencias significativas en la interacción de todas las clases, excepto entre 71-80 y 81-90 mm

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

The Argentine hake, Merluccius hubbsi, a demersal-pelagic species found from Rio de Janeiro, Brazil to the Tierra del Fuego, Argentina, has become an important target of the Brazilian bottom-trawler fleet since 2001. Earlier studies focusing on the species have suggested that more than one stock might occur off the Brazilian coast, in accordance with environmental features. In order to evaluate this hypothesis, fish were collected from four different areas in the Brazilian waters in which the hake is distributed, during the summers and winters of 1996-2001 and 2004, the females being used to analyze and compare spatial-temporal variations in ovarian maturation. Gonad indexes were also applied for the same purpose. Results indicate a north-south spawning gradient occurring as from summer at around 21°S to winter near 34°S, leading to the identification of two distinct stocks: one located between 21°S and 29°S (Southeastern stock) and the other between 29°S and 34°S (Southern stock), this latter shared with Uruguay and Argentina. Brazilian stocks present clear signs of overexploitation, the situation calling for an urgent solution.A merluza Merluccius hubbsi, espécie demerso-pelágica distribuída desde o Rio de Janeiro, Brasil, até a Terra do Fogo, Argentina, tornou-se alvo das frotas de arrasto de fundo da região Sudeste-Sul do Brasil desde 2001. Estudos anteriores sobre a biologia da espécie sugeriram a existência de mais de um estoque em águas brasileiras, relacionados a características ambientais. Para verificar esta hipótese, exemplares oriundos de quatro áreas em águas brasileiras foram coletados durante o verão e o inverno nos períodos 1996-2001 e 2004, sendo as fêmeas utilizadas para analisar variações espaço-temporais na maturação gonadal. Para corroborar estas análises também foram aplicados índices gonadais. Os resultados mostraram a ocorrência de um gradiente norte-sul para a desova, que é mais intenso no verão 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 último compartilhado com o Uruguai e a Argentina. Os estoques brasileiros apresentam sinais de sobrepesca, situação que merece atenção e medidas apropriadas de gestão

Desenvolvimento ovariano de Ariomma bondi Fowler, 1930 (Teleostei: ariammatidae) na região Sudeste-Sul do Brasil

Ariomma bondi é uma espécie demerso-pelágica comum na borda da plataforma e no talude continental da região Sudeste-Sul do Brasil. Nesta região, grandes biomassas da espécie foram detectadas durante o Programa REVIZEE, sendo A. bondi considerada um recurso pesqueiro potencial. Estudos sobre a estratégia reprodutiva são essenciais para compreensão da biologia das espécies e da dinâmica de populações. A análise do desenvolvimento ovocitário é fundamental para a caracterização da maturação ovariana. Para a identificação das fases do desenvolvimento ovocitário e dos estádios de maturação ovariana, foram realizadas análises histológicas de ovários. Foram identificadas cinco fases de desenvolvimento ovocitário e folículos pós-ovulatórios, sendo descritos cinco estádios de maturação. A. bondi apresentou desenvolvimento ovariano assincrônico. A análise histológica dose ovários foi fundamental para uma correta atribuição da maturação ovariana, sendo recomendada também a aplicação de outras técnicas de estudo para o correto diagnóstico da biologia reprodutiva da espécie

Atlas of marine bony fish otoliths (Sagittae) of Southeastern - Southern Brazil Part I: Gadiformes (Macrouridae, Moridae, Bregmacerotidae, Phycidae and Merlucciidae); Part II: Perciformes (Carangidae, Sciaenidae, Scombridae and Serranidae)

The drawings, detailed pictures, precise descriptions and measurements that characterize otoliths must be made available for studies in various areas, including taxonomy, phylogeny, ecology, fisheries, paleontology, diversity, predator-prey relationships and modeling. The Collection of Teleostei Fish Otoliths of Southeastern-Southern Brazil (COSS-Brasil) of IOUSP contains 45,000 pairs of otoliths from 210 species. This publication is the first in a series that will constitute an atlas of Teleostei otoliths for southeastern-southern Brazil and presents the results of the morphologic and morphometric analyses of 11 Gadiformes and 36 Perciformes species by means of the most commonly used features, measurements and indices. Three otoliths of each species were illustrated and photographed whenever possible. The frequency of occurrence was calculated for each characteristic by total length classes (TL), and the ontogenetic differences were analyzed (multiple χ2 test; significance 0.05). Morphometric analyses were conducted for each characteristic per total length (TL) class and for the whole sample, and the ontogenetic differences were analyzed.A disponibilidade de desenhos, fotos detalhadas, descrições precisas e medidas que caracterizem os otólitos são ferramentas imprescindíveis para diversas áreas: taxonomia, filogenia, ecologia, pesca, paleontologia, diversidade, relações presa/predador e modelagem. Da Coleção de Otólitos de Peixes Teleósteos da Região Sudeste-Sul do Brasil (COSS-Brasil), IOUSP, constam quarenta e cinco mil pares relativos a 210 espécies. Esta publicação é a primeira de uma série que constituirá um atlas de otólitos para Teleostei da região sudeste-sul brasileira e apresenta os resultados de análises morfológicas e morfométricas de 11 espécies de Gadiformes e 36 de Perciformes das medidas e índices usualmente realizados. Foram desenhados e fotografados três otólitos de cada espécie sempre que possível. A frequência de ocorrência foi calculada por classes de comprimento total (TL) e para toda a amostra, e diferenças ontogenéticas foram analisadas