RESILIENCE OF THE SHORTNOSE GUITARFISH (Zapteryx brevirostris): COMPLETE COMPENSATORY GAIN, HEMATOLOGY AND HISTOPATHOLOGY

Veronica Takatsuka,Ana Paula Dos Santos,Susy Hermes De Souza,Luciana Sonne,Eduardo Gomes Sanches,Venâncio Guedes De Azevedo

doi:10.20950/1678-2305.2019.45.2.355

Abstract

Compensatory gain has been used to evaluate the plasticity of species, in adverse situations such as food deprivation. The aim of the present study was to identify the type of compensatory gain achieved by the shortnose guitarfish (Zapteryx brevirostris), in situations of reduction of food resources. Three treatments were used: seven days of food deprivation and fourteen days of refeeding (T7x14); fourteen days of food deprivation and fourteen days of refeeding (T14x14); and feeding every day (TControl). Zootechnical performance, blood samples and histological samples were evaluated. We demonstrated that this species presented complete compensatory gain and that some blood parameters and histological alterations were associated with fasting.

Highlights

The species Zapteryx brevirostris (Müller & Henle, 1841), known as the shortnose guitarfish or lesser guitarfish, is the only species in its genus and has been classified as vulnerable (VU) by the International Union for Conservation of Nature (IUCN) (Vooren et al, 2006)
The objective of this study was to evaluate the physiological response of Z. brevirostris, a species classified as vulnerable by the IUCN, in situations of cyclical periods of food deprivation, and to ascertain whether there might be any hematological parameters and histological alterations that would elucidate the physiology of this species
Complete compensatory gain was achieved through the treatment T7x14, since the zootechnical performance and health data of this treatment group were similar to those of the control group (TControl)

Summary

Introduction

The species Zapteryx brevirostris (Müller & Henle, 1841), known as the shortnose guitarfish or lesser guitarfish, is the only species in its genus and has been classified as vulnerable (VU) by the International Union for Conservation of Nature (IUCN) (Vooren et al, 2006). It is mainly caught accidently in trawling for shrimps (Pinheiro and Martins, 2009). The potential of this species for recovery of its population size is low, given that an average of only three offspring are produced per year, per mature female (Vooren et al, 2006), and that it reaches sexual maturity late (Abilhoa et al, 2007)

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