Length–weight relationships for estuarine fishes in South Brazil

Abstract

Summary The present study reports the length‐weight relationships (LWRs) for 18 estuarine species sampled in Guaratuba Bay, South Brazil. For the majority of these 18 species the LWRs are known from the literature, but these estimates do not consider sexes separately which is done in this contribution. Different fishing gears were used in the samplings (cylindrical nets – 1 mm mesh size, bottom trawls – 250 mm mesh size in the arms and 12 mm mesh size in the bag, beach seine – 5 mm mesh size and hook and line fishery) between September 2007 to April 2014. The specimens were sexed and the LWRs were calculated for each sex separately. There were differences between sexes in growth type, showing the importance of sexing in these studies. We reported for the first time (based on FishBase) the LWRs for two species: Ctenogobius shufeldti and Hypleurochilus fissicornis.

Length–weight relationships comparison between juveniles and adults of fish species from the mangroves of south Brazil

“…Moreover, the sexual differences may have resulted in these discrepancies of b (general x separated sexes) when we grouped the individuals and compared them to the separated sexes, since their growth types are different. Concerning the fat snook, we presented the LWR for juveniles, while FishBase and other studies in near areas showed this relationship for adults (Froese & Pauly, 2019;Possamai et al, 2019). The juveniles here showed an allometric negative growth, which demonstrates the species is investing more in length than in weight.…”

“…The juveniles here showed an allometric negative growth, which demonstrates the species is investing more in length than in weight. This is different from the adults which exhibit allometric positive growth (Possamai et al, 2019). When the fat snook reaches maturity (about 194 mm) (Chaves & Nogueira, 2018), it starts as a male and then becomes female (protandric hermaphroditism).…”

“…Juveniles of fishes commonly use mangrove areas (McLusky, 1990;Haimovici & Ca rdoso, 2017;Pelage et al, 2019;Taylor et al, 2018), but some biological parameters for this life stage are missing in the literature since the majority of research on growth estimations, for example, are focused on adults (Morato et al, 2001). Length-weight relationship (LWR) is a species-specific biological index that is easy to obtain, and is very important for obtaining insights about population growth, reproduction, and health condition (Le Cren, 1951;Petrakis & Stergiou, 1995;Possamai, Zanlorenzi, Machado , & Fávaro, 2019).…”

“…The LWR is influenced by temperature, interspecific relationships, resource availability, sex, and life stage (Froese, 2006;Nallathambi et al, 2019;Possamai et al, 2019). Therefore, studies of fish stock structure and biomass estimations need to consider the geographic region of the coefficients used to estimate the LWR (LeCren, 1951;Petrakis & Stergiou, 1995;Gonçalves et al, 1997), as well as the life stage of the specimens (Petrakis & Stergiou, 1995;Gonçalves et al, 1997).…”

Growth and fillet yield in recirculation systems of Lobotes pacificus (Perciformes: Lobotidae), a species with aquaculture potential

“…1), which indicates that this group first increased in weight and then in length. It is inferred that this variation in the b value between the groups is due to differences in size and weight ranges for each group at the beginning of the study since the coefficient can change between populations of the same species depending on life cycle stages (Bagenal, 1978;Cibert et al 1999;Sá et al 2000;Possamai et al 2018), as well as to the low consumption of feed in D1 with respect to the high consumption of sardine in D2. Both b values were higher than those found by Leiva et al (2007) for the same species captured in Colombian waters (b = 2.656).…”