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. 2018 Aug 7:6:e5392.
doi: 10.7717/peerj.5392. eCollection 2018.

Incidental catch of loggerhead sea turtles (Caretta caretta) along the Sicilian coasts by longline fishery

Santo Caracappa  1 , Maria Flaminia Persichetti  1 , Antonio Piazza  1 , Giulia Caracappa  1 , Antonino Gentile  1 , Sandra Marineo  1 , Daniela Crucitti  1 , Marco Arculeo  2
Affiliations

Incidental catch of loggerhead sea turtles (Caretta caretta) along the Sicilian coasts by longline fishery

Santo Caracappa et al. PeerJ. .

Abstract

It has been estimated that 44,000 Caretta caretta turtles die every year due to anthropomorphic activity in the Mediterranean Sea, and that longline fishing is one of the most significant causes of mortality. A total of 482 specimens of C. caretta were rescued from different parts of the Sicilian coast (Mediterranean Sea) from 2014 to 2016. The most numerous stranding was recorded during the spring and summer seasons, mainly along the north and eastern coasts of Sicily. The curved carapace length for all the specimens ranged from between 19 and 95 cm and most of these were young or sub adults. The highest number of strandings was recorded in 2014 and 2015, with 206 and 169 individuals, respectively. A total of 66 live specimens out of 239 were successfully rehabilitated and released after surgery or drug therapy; fishing hooks were found in 129 specimens in different parts of the digestive tract with greater frequency in the oesophagus (47.3%) followed by the gut (24.8%), stomach (14.7%), and mouth (13.2%). This paper will highlight the incidence of the incidental catch by longline fishing of C. caretta along the Sicilian coasts and also relate the size of ingested hooks to the size of examined specimens.

Keywords: Caretta caretta; Hooks; Incidental take; Loggerhead turtle; Longline fishing; Mediterranean Sea; Sicily; Strandings.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Figure 1
Figure 1. Origin of the specimens of C. caretta stranded.
The size of circles represents the number of strandings found along the Sicilian coasts.
Figure 2
Figure 2. Seasonal percentage C. caretta stranded along Sicilian coasts.
Figure 3
Figure 3. X-ray of C. caretta.
(A) Turtle rescued in Noto locality (South of Sicily) with two hooks in the esophagus. (B) Turtle rescued in Filicudi locality (Northeast of Sicily) with one hook in the intestine.
Figure 4
Figure 4. Intestinal torsion and obstruction caused by ingested line.
Figure 5
Figure 5. Different size of J-hooks found in different tract of the digestive system.
On the left (first and second group hook sizes about 80 and 40–50 mm). On the right (first and second group hook sizes about 20 and 30 mm).
Figure 6
Figure 6. Distribution of the number and the size (range: 21–40, 41–60, and 61–80 mm) of hooks in relation to the carapacial size (CCL) in cm of the rescued C. caretta specimens.
See this image and copyright information in PMC

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