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

Abstract

Despite the fact that Mediterranean loggerhead turtles are listed as "Least Concern" by the International Union for the Conservation of Nature (IUCN), they are among the most threatened marine megafauna 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 midwater 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.

Is Caretta Caretta a Carrier of Antibiotic Resistance in the Mediterranean Sea?

“…Caretta caretta is the most abundant sea turtle species in the Mediterranean Sea and is the subject of numerous studies and research programs aimed at its protection and conservation. Many events, such as incidental catches by fishing [19,20], water pollution [16], presence of fungi in egg nests [21] and global climatic changes, affect the health status and conservation of sea turtles [22]. To the best of our knowledge, few studies [13,17,18,23] evaluated the frequency of antibiotic-resistant bacteria isolated from adult loggerhead sea turtles in the Mediterranean Sea.…”

Bottlenose Dolphin (Tursiops truncatus) Whistle Modulation during a Trawl Bycatch Event in the Adriatic Sea

“…Since 2006, an extensive monitoring program of bycatch of long-lived species like cetaceans, sea turtles, and elasmobranchs by Italian midwater pair trawlers has been conducted in the northern central Adriatic Sea [ 22 , 23 ]. The information collected in its framework provides a unique opportunity to assess the operational details of capture events and the abundance trends of species over time [ 24 ].…”

A 14-year time series of marine megafauna bycatch in the Italian midwater pair trawl fishery

“…This procedure was applied in a delta www.nature.com/scientificdata www.nature.com/scientificdata/ modelling approach which allowed to model the probability of species occurrence and the magnitude of catch events separately (see details in 28 ). The results indicated that the predictive accuracy of the delta-modelling strategy was rather good and a similar approach was used by 30 to evaluate the seasonal distribution of bycatch events of loggerhead (Caretta caretta). Furthermore, Zero-inflated General Linear Models (GLMs) were used by 29 to examine the relative abundance of four elasmobranch species -common smooth-hound (Mustelus mustelus), common eagle ray (Myliobatis aquila), spiny dogfish (Squalus acanthias), and pelagic stingray (Pteroplatytrygon violacea) -included in the dataset.…”

“…In addition, users should consider that the datasets include fishery-dependent data which can suffer of intrinsic bias related to the stochasticity of the distribution a. www.nature.com/scientificdata www.nature.com/scientificdata/ of marine megafauna and a lack of a well-defined sampling design of the monitoring activity in space and time. Indeed, following the considerations in 27,29,30 a non-equal distribution of the monitoring activity was conditioned by fleet dynamics (e.g., fishing closure, fish market preferences and price) and bureaucratic delays of the project, which affected both observed pattern and estimation of bycatch events.…”