Length–weight relationships for estuarine fishes in subtropical estuary

Bárbara Maichak De Carvalho ,Henry Louis Spach,Renato Bot

doi:10.4025/actascibiolsci.v42i1.51495

Bárbara Maichak De Carvalho , Henry Louis Spach + Show 1 more

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https://doi.org/10.4025/actascibiolsci.v42i1.51495

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Abstract

The present study describes the length/weight ratio (LWR) of 20 fish species caught in an intertidal area of the Paranaguá Estuarine Complex, southern Brazil. Fish were caught with three beach seine nets, with 2m high, 70m long and distance between knots of 2.5; 4 and 5cm. A total of 880 individuals of 21 species belonging to 11 families were captured, ranging from 5 to 75.5cm in total length. All species analyzed are widely distributed throughout the Southwestern Atlantic. Positive allometric growth (b > 3) was predominant, occurring in 60% species, 35% presented negative allometry (b < 3) and only 5% had isometric growth (b = 3). Many factors could be influencing the distinct growth patterns observed between the literature and the present study, such as the environmental influences, the reduced number of specimens, the sampling methods, the sampling periods and the estimation of the LWR with grouped sexes.

Highlights

The length-to-weight ratio (LWR) is an important parameter that allows biomass estimates (Le Cren, 1951; Froese, 2006), assisting in the elaboration of stock and growth models (Haimovici & Velasco, 2000), enabling the identification of animal health state. (Possamai, Zanlorenzi, Machado, & Fávaro, 2019) and, through the allometric coefficient (b) of the LWR, verifying the type of fish growth
The present study showed the LWR of 21 species widely distributed on the southwest coast of the South Atlantic (Cervigón, 1993), which use the estuary for breeding and growth and are part of the bycatch in artisanal fisheries (Cattani, Santos, Spach, Budel, & Gondim Guanais, 2011; Santos, Cattani, & Spach, 2016)
Positive allometric) of specimens collected in the Paranaguá Estuarine Complex, Southwestern Atlantic

Summary

Introduction

The length-to-weight ratio (LWR) is an important parameter that allows biomass estimates (Le Cren, 1951; Froese, 2006), assisting in the elaboration of stock and growth models (Haimovici & Velasco, 2000), enabling the identification of animal health state. (Possamai, Zanlorenzi, Machado, & Fávaro, 2019) and, through the allometric coefficient (b) of the LWR, verifying the type of fish growth (allometric/isometric; Carvalho, Barradas, Fontoura, & Spach, 2017). The present study showed the LWR of 21 species widely distributed on the southwest coast of the South Atlantic (Cervigón, 1993), which use the estuary for breeding and growth and are part of the bycatch in artisanal fisheries (Cattani, Santos, Spach, Budel, & Gondim Guanais, 2011; Santos, Cattani, & Spach, 2016). These species are reported in the literature as prey for ichthyophagous species (Miotto, Carvalho, & Spach, 2017; Rupil, Barbosa, Marcondes, Carvalho, & Farro, 2019)

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