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

Abstract

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 (r 2 ) and residual analysis were employed to verify the appropriateness of fit. The coefficient b values were tested with respect to isometry (b=3) using a t a1,0.05 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. Resumo: 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 (r 2 ) e a análise de resíduos foram empregados para verificar a adequação dos ajustes. Os valores dos coeficientes b foram testados em relação à isometria (b=3) através de teste t a1, 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. Palavras-chave: crescimento relativo, alometria, peixes pelágicos e demersais. Results and DiscussionThe data from 13,222 fish comprising five orders, fifteen families and twenty-five species were analyzed. Table 1 shows the species analyzed, the ranges and means of their length, the number of fishes, the parameters of the length-weight relationships, the coefficients of determination and the results of the allometric t tests. The fitted models were biologically and statistically adequate to describe the length-weight relationship for all species. A model of residual analysis is presented in Figure 2 and all assumptions (normality, randomness, homoscedasticity and independence) showed no tendency for all species. Random residuals have showed that models were adequate (Bervian et al. 2006).The minimum and maximum values of b for the length-weight relationships were, respectively, 2.377 and 3.538, and its frequency distribution is presented in Figure 3.It is noteworthy that b provided the best estimates for those typical small pelagic fish which were caught by the mid-water trawl and seine, such as the Clupeiformes,

Reproductive biology and recruitment of bluefish Pomatomus saltatrix (Perciformes: Pomatomidae) in the southwestern Atlantic

“…These parameters are also useful for estimating biomass and weight growth (Froese 2006), allowing comparisons between fish species or populations from different habitats (Froese andPauly 1998, Nahum et al 2009). Previous studies have shown that the "b" values of P. saltatrix for juveniles (b = 3.051 to 3.336) and adults (b = 2.509 to 2.899) recorded in different habitats Barger 1990, Torres 1991, Haimovici and Velasco 2000, Frota et al 2004, Kalayci et al 2007, Ak et al 2009, Vaz-dos-Santos and Rossi-Wongtschowski 2013, Cumplido et al 2018 were in line with the values estimated in the present study. Therefore, the b coefficient becomes an essential parameter for the evaluation of stocks, which is used to determine the health status and well-being of the individuals of a population, influenced by environmental factors, food availability, and reproductive period (Rossi-Wongtschowski 1977).…”

Length-weight relationships for 22 neotropical freshwater fishes from a subtropical river basin

“…The linear least square method was applied to the data logarithms. Models were verified through residual analysis (with outliers removed) and the values of the coefficient of determination (Vaz-dos-Santos and Rossi-Wongtschowski, 2013).…”

Length-Weight Relationship of the Six Most Abundant Fish Species in Prawn Fishery Semi-Fixed Trap Bycatches in the Lower Amazon Region (Pará, Brazil)

“…These data are helpful in biomass calculations and generate indirect information on maturity, reproduction, and nutrition (Froese et al, 2011(Froese et al, , 2014, which are frequently used for economically important fish. The length and weight parameters also permit growth comparisons between species from different regions, as well as the monitoring of the health of stocks over time (Vaz-dos-Santos and Rossi-Wongtschowski, 2013;Silva et al, 2020).…”