Length-weight relationships and length at first maturity for nine fish species of floodplain lakes in Central Amazon (Amazon Basin, Brazil)

Abstract

Length-weight relationships are presented for nine fish species from the floodplain lakes in the Central Amazon (Amazon Basin, Brazil). The parameter slope b values in the length-weight relationships ranged from 2.33 to 3.28 for grouped sexes, and from 2.7 to 3.61 for separated sexes. Differences between sexes were verified in three species. Sizes at first sexual maturation ranged from 9.14 to 23.97. This study provides a new reference for the length-weight relationships of six species.

Life-history traits of Farlowella hahni (Siluriformes, Loricariidae) in streams of the Ivinhema River Basin, Upper Paraná Basin

“…Still, little is known about small Loricariidae, which, from an ecological perspective, occur in relatively low abundance. Consequently, we need to know more about the life-history of Farlowella species in order to understand population structure and reproductive success, allowing us to, in turn, evaluate their conservation status and formulate appropriate management strategies (Giarrizzo et al, 2011;Dieb-Magalhães et al, 2015).…”

Length-weight relationship and condition factor for twelve fish species from the Igarapé Fortaleza basin, a small tributary of the Amazonas River estuary

“…The length-weight relationship (LWR) is a mathematic model that allows for the conversion of length into weight, and weight into length in stock assessment models, as well as the estimation of biomass from the length frequency distribution. LWR can be used to determine possible differences between separate stock units of a species, provided all units are studied with the same fully standardized sampling methodology (Dieb-Magalhães et al 2015;Freitas et al 2017;Baitha et al 2018). LWR is also used for estimating the condition factor of fish, which is used to compare the health of fish populations.…”

“…The analysis of LWR and condition factor of fish populations are important tools to support the rational management of fishing resources, and may help in the implementation of public policies (Dieb-VOL. 50(1) 2020: 8 -11 ACTA AMAZONICA Magalhães et al 2015;Giarrizzo et al 2015;Silva et al 2015;Baitha et al 2018). LWR studies for freshwater fish species from the Amazonas River basin have increased, providing important biological information on fish populations (e.g.…”

“…LWR studies for freshwater fish species from the Amazonas River basin have increased, providing important biological information on fish populations (e.g. Freitas et al 2014;Silva et al 2015;Giarrizzo et al 2015;Cella-Ribeiro et al 2015;Dieb-Magalhães et al 2015;Freitas et al 2017). However, there still are large gaps in the geographical coverage of biological data for many fish widely distributed in the Amazon basin.…”

“…These lower b values for A. tetramerus and A. nuchalis and higher values for T. galeatus may be due to various factors. The growth type of fish species can be changeable, depending on the season, food availability, population, sex or physiology (Silva et al 2015;Giarrizzo et al 2015;Cella-Ribeiro et al 2015;Dieb-Magalhães et al 2015;Freitas et al 2017). Therefore, more data, from a larger sample size, are needed to confirm these extreme growth pattern values.…”