A new strategy proposal to monitor ray fins landings in south‐east Brazil

Abstract

Statistical fisheries data are usually obtained during landings, through rapid fish classification and their categorization under the trade names given to species or groups of species. However, species classification is often difficult, particularly concerning elasmobranchs whose fins and heads have been removed, leading to labelling errors. The aim of this paper is to identify the ray species composition landed in south‐east Brazil, providing identification strategies to support a plan for more efficient labelling and management. Samples were obtained from artisanal fleet landings, between November 2012 and May 2014. For taxonomic identification of whole or processed animals (n = 279, belonging to 10 species), morphological, metric, and molecular techniques were employed. The common name used by fishermen was more related to the location where they lived than the fishing gear used. Morphometric analyses resulted in pectoral fin to length and weight conversion equations of whole individuals for each species, and 10 variables were found to be diagnostic of each genus. A genetic identification, based on sequencing of the mitochondrial genes cytochrome b and cytochrome oxidase I, was applied to verify morphological identification. A dichotomous key that allowed ray identification at the species level from pectoral fin morphology was developed. The approach was field tested and deemed adequate, leading to a robust monitoring strategy for estimating the biomass of specific landed rays.

On mobulid rays and metals: Metal content for the first Mobula mobular record for the state of Rio de Janeiro, Brazil and a review on metal ecotoxicology assessments for the Manta and Mobula genera

“…No comparison to disk length is, however, reported in the literature, only to disk width, reported as 11.9% (Notabartolo Di Scaria, 1987). Ray identification and size assessments through the investigation of fin to body ratios have only been successfully applied in cases of isolated fins and shown to be a valuable tool in this regard (Almeida Marques et al, 2020;Appleyard et al, 2018). Therefore, the mouth to disk length may be an interesting complementary ratio to account for missing pectoral fins in future studies and should be further investigated and routinely reported in studies on manta rays.…”

Integrative taxonomy identifies a new stingray species of the genus Hypanus Rafinesque, 1818 (Dasyatidae, Myliobatiformes), from the Tropical Southwestern Atlantic

“…To determine if H. americanus constitutes a broadly distributed species or a species complex, samples, specimens and records of all putative H. americanus , along with the closely related H. longus and H. rudis , were assessed. This information will be useful to evaluate the conservation status and to support fisheries management policies of Atlantic stingrays to be effective (Almeida Marques et al ., 2019; Dulvy et al ., 2017; Lima et al ., 2019).…”