Growth and mortality estimates of Sardinella brasiliensis in the southeastern Brazilian bight

Abstract

Length frequency analisys were applied for sardine data collected from commercial catches throughout the southeastern Brazilian coast in 1977-1987. Age/length keys were obtained by otolith ring countings and utilized to transform length into age composition. Growth parameters were estimated by the von Bertalanffy growth equation using age and length data for each year and for all the period of investigation. The mean growth parameters for the entire period were estimated as L&#8734; = 271 mm and K= 0.59 year-1. Instantaneous total mortality (Z) coefficients per year were estimated using catch curves and methods based on the mean length of the fish caught. Total mortality rate for the entire period was obtained through the average of the annual values. Natural mortality (M) was estimated using the Paul/s empirical equation (1980a), and fishing mortality (F) by the difference between total and natural mortality values.The results were Z = 3.6 year-1; M = 0.96 year-1; and F= 2.6 year-1.<br>Estudo sobre o crescimento e a mortalidade de Sardinella brasiliensis, da costa sudeste do Brasil, foi realizado para o período 1977 a 1987. As análises foram efetuadas a partir de dados existentes sobre distribuições de freqüência de comprimento de amostras da captura comercial. Chaves idade/comprimento, construidas a partir de leitura de anéis de crescimento em otólitos, dentro do Programa Integrado de Estudos Biológicos sobre a Sardinha - PIEBS, foram utilizadas para transformar as distribuiçes de comprimento em idade. Os parâmetros de crescimento da equação de von Bertalanffy foram estimados, anualmente e para o período como um todo, a partir de métodos que utilizam dados de idade e comprimento. Os parâmetros médios encontrados para o período foram: L&#8734; = 271 mm e K= 0,59 ano-1. Os coeficientes instantâneos de mortalidade total (Z) anuais foram calculados pelas curvas de captura e por métodos baseados no comprimento médio dos indivíduos nas capturas. A mortalidade total para todo o período foi obtida pela média dos valores anuais. O coeficiente instantâneo de mortalidade natural (M) foi estimado pela equação empírica de Pauly (1980a), usando um fator de correção de 0,8 para clupeoides, e o coeficiente instantâneo de mortalidade por pesca (F), pela diferença entre a mortalidade total e a natural. Os valores encontrados foram: Z= 3,6 ano-1, M = 0,96 ano-1 e F= 2,6 ano-1

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

“…As demonstrated by our results, higher "b" values are related to smaller otoliths, which are present in the summer, when an additional ring forms in the otoliths in association with the extensive spawning that began in the spring . As only one cohort is produced per year, adult ring formation in otoliths is related to the beginning and to the end of the spawning peak (Cergole & Valentini, 1994).…”

“…Due to its economic importance, the sardine has been subject of many studies including those investigating growth (Braga, 1982;1987;RossiWongtschowski et al, 1982;Vazzoler et al, 1982;1987;Saccardo et al, 1988;Cergole & Valentini, 1994;Cergole & Rossi-Wongtschowski, 2005;Fonteles-Filho et al, 2005;Cergole & Dias Neto, 2011). Huxley (1993)'s classic treatment of the theme of relative growth established a conceptual framework for the use of size relationships in morphometric studies.…”

Otolith dimensions (length, width), otolith weight and fish length of Sardinella sindensis (Day, 1878), as index for environmental studies, Persian Gulf, Iran

“…In addition, sardines are consumed as fresh meal for humans and as commercial powder (Bennet et al 1992;Hill et al 2005;FAO, 2011). Many studies for sardine genus have been performed on the otolith structures, such as growth and mortality estimation, identification of fishes, determine the fish stock and trace migration pathway of fish (Nair, 1949;Krzeptowski, 1983;Cergole & Valentini 1994;Butler et al 1996;Watanabe & Nakamura, 1998;Gaughan & Mitchell, 2000, Silva et al 2008Mehanna & Salem 2011;Ward et al 2012;Dehghani et al 2015). According to FAO (2011), Sardinella sindensis is the most important commercial fish for Iran and Pakistan.…”

Modeling the spawning strategies and larval survival of the Brazilian sardine (Sardinella brasiliensis)

“…This Ichthyop model considers two sources of mortality: one is related to lethal water temperature, where the individuals are considered dead if they experience water temperatures <17°C (for eggs) and <16.5°C (for larvae) (Kurtz, 1999); the other is related to loss by advection, which occurs when larvae are located in areas deeper than 200 m or out of the model domain by the end of simulation. Beyond this depth limit larvae tend to die by starvation (Cergole and Valentini, 1994;Saccardo and Rossi-Wongtchowski, 1991). Finally, the larval survival rate was calculated relative to the total number of individuals released excluding the individuals that died by temperature or were advected offshore.…”