Bycatch of Loggerhead Turtle (Caretta caretta) in the Italian Adriatic Midwater Pair Trawl Fishery

Jacopo Pulcinella,Alessandro Colombelli,Fabrizio Moro,Antonello Sala,Alessandro Lucchetti,Caterina Maria Fortuna,Sara Bonanomi

doi:10.3389/fmars.2019.00365

Abstract

Despite the fact that Mediterranean loggerhead turtles are listed as ‘Least Concern’ by the IUCN, they are among the most threatened long-lived marine species worldwide, because of fishery-related incidental captures. The northern central Adriatic Sea is one of the most overfished basins of the Mediterranean Sea and it supports a very valuable marine biodiversity, including sea turtles. This study assesses the spatial and seasonal impact of the northern central Adriatic pelagic/mid-water pair trawl fishery on loggerhead turtle (Caretta caretta) by examining incidental catches recorded between 2006 and 2018 and environmental variables. The model predicted seasonal variation of loggerhead distribution. According to previous studies, data analysis indicates that most bycatch events of loggerhead turtle occurred in the northern Adriatic Sea. The present data confirm that the northern Adriatic may be an important foraging area for loggerhead turtle. They also highlight the urgent need for a better understanding of the interactions between sea turtles and fisheries to develop and apply suitable, ad hoc management measures in critical habitats.

Highlights

The incidental capture of non-target species occurring during fishing operations (e.g., Davies et al, 2009; Ortuño Crespo and Dunn, 2017) is one of the major global threat to marine megafauna of conservation concern (e.g., Worm et al, 2006; Lewison et al, 2014)
This must be true for fishery management frameworks too, which should be informed by a wide range of information, including spatial patterns of interactions and biological data on concerned species
The interactions between loggerhead turtle and fishing gears have usually been ascribed to bottom trawlers (Casale et al, 2004; Lucchetti and Sala, 2010; Lucchetti et al, 2016), midwater pair trawlers (Casale et al, 2004; Fortuna et al, 2010), rapido trawlers (Lucchetti et al, 2018), and set nets (Lucchetti et al, 2017)

Summary

Introduction

The incidental capture of non-target species occurring during fishing operations (e.g., Davies et al, 2009; Ortuño Crespo and Dunn, 2017) is one of the major global threat to marine megafauna of conservation concern (e.g., Worm et al, 2006; Lewison et al, 2014) Among those species, sea turtles are vulnerable to the effects of bycatch given their biological and ecological characteristics (e.g., long life cycle, seasonal distribution patterns, long-distant foraging migrations, etc.) and the intensity of fishing effort across a various range of gears (e.g., Veiga et al, 2016; Lewison et al, 2013; Gray and Kennelly, 2018 and references there in). Entanglement and capturing by different fishing gears usually intended to catch valuable commercial species are among the major threats to sea turtles from fisheries

Methods

Results

Conclusion