First study of sea turtle strandings in Algeria (western Mediterranean) and associated threats: 2016–2017

Abstract

Between December 2015 and December 2017 a total of 63 sea turtles were recorded as being stranded along the Algerian coast. The loggerhead sea turtle Caretta caretta was the most commonly stranded species (n = 44) (69.8%), followed by the leatherback Dermochelys coriacea (n = 18) (28.6%) and the green turtle Chelonia mydas (n = 1). There was a slight dominance of the adult size class for stranded loggerhead turtles, while, for the leatherback, late juveniles and adults prevailed. Most loggerhead turtles stranded during the summer months (July and August), whereas most leatherbacks stranded during winter. The breakdown of the strandings by region shows a slight dominance along the western and central shores for C. caretta and a clear dominance in the west for D. coriacea. The primary cause of death was determined in 50.8% of the stranded turtles. Regarding the evidence of interactions with humans the major cause of stranding in loggerhead turtles was incidental catch by artisanal fisheries, followed by boats’ collisions. The main causes of leatherback strandings were boats’ collisions. Algerian data show that human activities affect loggerhead turtles and also prove a significant presence of the leatherback turtle on this coast.

Identifying the foraging grounds of the new loggerhead turtle nesters in the western Mediterranean

“…For this reason, any potential increase in the bluefin tuna quotas for the longline fleet in the western Mediterranean should be accompanied by measures aimed at reducing loggerhead turtle bycatch, such as avoiding the use of squid as bait and deploying hooks deeper than 25 m (Swimmer et al, 2017), which must be considered by all countries involved in the fishery. Furthermore, bycatch in other fisheries should also be reduced, as adult loggerhead turtles are often captured incidentally by artisanal fisheries operating off Morocco and Algeria (Belmahi et al, 2020; Mghili et al, 2023). Considering that regional population estimates for the Mediterranean population are likely to be considerably overestimated (Rees et al, 2020), the conservation of any adult loggerhead turtle is more important than previously thought.…”

A tentative list of reptilian fauna of Algeria and their conservation status

“…The presence of sea turtles along the Algerian coast is regularly reported, with many beachings, of which 70% are the loggerhead turtle, Caretta caretta (Linnaeus, 1758) and 30% of the leatherback Sea turtle, Dermochelys coriacea (Vandelli, 1761) ( Bennounas and Bennounas 2020 , Belmahi et al 2020 ). The green Sea turtle Chelonia mydas (Linnaeus, 1758) is the rarest species, having been recorded only once since 2003 (Bennounas and Tifoura 2020).…”

The area south of the Po River delta (Italy) is a hot spot for strandings of loggerhead sea turtles

“…The number of stranded sea turtles•km −1 , as well as the absolute numbers of strandings during the four years, clearly confirmed that the area south of the Po River delta is the most impacted in Italy (Casale et al ., 2010) and perhaps in the whole Mediterranean Sea (Tomás et al ., 2008; Bellido et al ., 2010; Corsini-Foka et al ., 2013; Türkozan et al ., 2013; Belmahi et al ., 2020; Hama et al ., 2020; Dimitriadis et al ., 2022). Although the extension of the monitored area appeared to be much greater, only Karaa et al .…”