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Sea turtle strandings, sightings and accidental catch along the Croatian Adriatic coast

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The northern Adriatic Sea has long been known as the foraging and developmental habitat of loggerhead sea turtles. Previous literature on stranded, floating, sighted, and accidentally caught sea turtles is fragmentary and mainly obtained from this shallower northern part. This work presents data on 272 records of stranded, floating, sighted and accidentally captured turtles within the entire Croatian Adriatic. The data was collected through the national stranding network for strictly protected marine species run by the Croatian Agency for the Environment and Nature during a six-year period (2010-2015). We focused on analysing spatial and temporal observations, age structure, and reporting sources. The collected morphometric data revealed that most measured C. caretta (85%) were immature individuals found stranded and floating at sea. These observations were location-dependent with a tendency towards the shallow northern areas (≤200 m). Most of the stranded individuals were severely decomposed preventing the determination of possible mortality causes. Most non-decomposed individuals had fishery- or boat-inflicted mechanical injuries confirming fishing activities and boat collisions as threats to young C. caretta individuals in the Croatian Adriatic Sea. Results also revealed an important contribution of local people in reporting the C. caretta strandings and sightings whereas most accidentally caught individuals were reported by unknown sources. Altogether, the data presented in this paper indicate possibilities for improving the ongoing sea turtle monitoring and conservation activities along the entire Croatian Adriatic coast.


East Adriatic Sea; Caretta caretta; spatial observations; temporal observations; age structure; reporting sources.

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Affronte, M., Scaravelli, D., 2001. Analyses of stranded sea turtles in the north-western Adriatic Sea. Zoology in the Middle East, 24, 101-108.

Arnold, E.N., Burton, J.A., 1985. A field guide to the reptiles and amphibians of Britain and Europe. Collins, London, 272 pp.

Caminas, J.A., 2004. Sea turtles of the Mediterranean Sea: population dynamics, sources of mortality and relative importance of fisheries impacts. FAO Fisheries Report, No 738 (Supplement), 27 pp.

Casale, P., 2011. Sea turtle by-catch in the Mediterranean. Fish and Fisheries, 12, 299-316.

Casale, P., 2015. Caretta caretta (Mediterranean subpopulation). The IUCN Red List of Threatened Species 2015: e.T83644804A83646294 http://dx.doi.org/10.2305/ IUCN.UK.2015-4.RLTS.T83644804A83646294.en. (Accessed 15 June 2017).

Casale, P., Margaritoulis, D., 2010. Sea turtles in the Mediterranean: Distribution, threats and conservation priorities. Gland, Switzerland: IUCN, 294 pp.

Casale, P., Tucker, A.D., 2017. Caretta caretta (amended version of 2015 assessment). The IUCN Red List of Threatened Species 2017: e.T3897A119333622 https://dx.doi.org/ 10.2305/IUCN.UK.2017-2.RLTS.T3897A119333622.en. (Accessed 3 June 2020).

Casale, P., Nicolosi, P., Freggi, D., Turchetto, M., Argano, R., 2003. Leatherback turtles (Dermochelys coriacea) in Italy and in the Mediterranean basin. Herpetological Journal, 13, 135-139.

Casale, P., Laurent, L., De Metrio, G., 2004. Incidental capture of marine turtles by the Italian trawl fishery in the north Adriatic Sea. Biological Conservation, 119, 287-295.

Casale, P., Freggi, D., Basso, R., Argano, R., 2005. Size at male maturity, sexing methods and adult sex ratio in loggerhead turtles (Caretta caretta) from Italian waters investigated through tail measurements. Herpetological Journal, 15, 145-148.

Casale, P., Cattarino, L., Freggi, D., Rocco, M., Argano, R., 2007. Incidental catch of marine turtles by Italian trawlers and longliners in the central Mediterranean. Aquatic Conservation, 17, 686-701.

Casale, P., Affronte, M., Insacco, G., Freggi, D., Vallini, C. et al., 2010. Sea turtle strandings reveal high anthropogenic mortality in Italian waters. Aquatic Conservation: Marine and Freshwater Ecosystems, 20, 611-620.

Casale, P., Conte, N., Freggi, D., Cioni, C., Argano, R., 2011. Age and growth determination by skeletochronology in loggerhead sea turtles (Caretta caretta) from the Mediterranean Sea. Scientia Marina, 75, 197-203.

Casale, P., Affronte, M., Scaravelli, D., Lazar, B., Vallini, C. et al., 2012. Foraging grounds, movement patterns and habitat connectivity of juvenile loggerhead turtles (Caretta caretta) tracked from the Adriatic Sea. Marine Biology, 159, 1527-1535.

Casale, P., Broderick, A.C., Camiñas, J.A., Cardona, L., Carreras, C. et al., 2018. Mediterranean sea turtles: current knowledge and priorities for conservation and research. Endangered Species Research, 36, 229-267.

Dell Inc., 2016. Version 13.2 software Dell Inc., Tulsa, OK, USA.

Eckert, K.L., Bjorndal, K.A., Abreu-Groboisand, F.A., Donelly, M., 2000. Tecnicas de Investigacion y Manejo para la Conservacion de las Tortugas Marinas. Grupo Especialista en Tortugas Marinas UICN/CSE Publicacion, No 4, 260 pp.

ESRI (Environmental Systems Resource Institute), 2013. ArcGIS 10.2. ESRI, Redlands, California, USA.

Gamulin-Brida, H., 1967. The benthic fauna of the Adriatic Sea. Oceanography and Marine Biology–an Annual Review, 5, 535-568.

Gerosa, G., Casale, P., 1999. Interaction of Marine Turtles with Fisheries in the Mediterranean. UNEP Regional Activity Centre for Specially Protected Areas Report: Mediterranean Action Plan, 59 pp.

Godley, B.J., Gucu, A.C., Broderick, A.C., Furness, R.W., Solomon, S.E., 1998. Interaction between marine turtles and artisanal fisheries in the eastern Mediterranean: a probable cause for concern? Zoology in the Middle East, 16, 49-64.

Jelić, D., Kuljerić, M., Koren, T., Treer, D., Šalamon, D. et al., 2012. Crvena knjiga vodozemaca i gmazova Hrvatske. Državni zavod za zaštitu prirode, Zagreb, 232 pp.

Lazar, B.,Tvrtković, N., 1995. Marine turtles in the eastern part of the Adriatic Sea: preliminary research. Natura Croatica, 4, 59-74.

Lazar, B., Tvrtković, N., 2003. Corroboration of the critical habitat hypothesis for the loggerhead sea turtle Caretta caretta in the eastern Adriatic Sea. p. 165-169. In: Proceedings of the First Mediterranean Conference on Marine Turtles. Margaritoulis, D., Demetropoulos, A. (Eds). Barcelona Convention–Bern Convention–Bonn Convention (CMS).

Lazar, B., Borboroglu, P.G., Tvrtković, N., Žiža, V., 2003. Temporal and spatial distribution of the loggerhead sea turtle, Caretta caretta, in the eastern Adriatic Sea: a seasonal migration pathway? p. 283-284. In: Twenty-Second Annual Symposium on Sea Turtle Biology and Conservation. Seminoff, J.A. (Eds). NOAA Technical Memorandum NMFS-SEFSC-503 USA.

Lazar, B., Margaritoulis, D., Tvrtković, N., 2004. Tag recoveries of the loggerhead sea turtle, Caretta caretta, in the eastern Adriatic Sea: implications for conservation. Journal of the Marine Biological Association of the United Kingdom, 84, 475-480.

Lazar, B., Žiža, V., Tvrtković, N., 2006. Interactions of gillnet fishery with loggerhead sea turtles Caretta caretta in the northern Adriatic Sea. p. 252-253. In: Twenty-Sixth Annual Symposium on Sea Turtle Biology and Conservation, Crete, 3-8 April 2006. International Sea Turtle Society, Athens.

Lazar, B., Lipej, L., Holcer, D., Onofri, V., Žiža, V. et al., 2008a. New data on the occurrence of leatherback turtles Dermochelys coriacea in the eastern Adriatic Sea. Vie Milieu, 58, 237-241.

Lazar, B., Gračan, R., Zavodnik, D., Tvrtković, N., 2008b. Feeding ecology of “pelagic” loggerhead turtles, Caretta caretta, in the northern Adriatic Sea: proof of an early ontogenic habitat shift. p. 93-93. In: Proceedings of the Twenty-Fifth Symposium on Sea Turtle Biology and Conservation. Kalb, H., Rohde, A.S., Gayheart, K., Shanker, K. (Eds). NOAA Technical Memorandum NMFS-SEFSC, USA.

Levy,Y., Frid, O.,Weinbergerb, A., Sadeb, R., Adam, Y. et al., 2015. A small fishery with a high impact on sea turtle populations in the eastern Mediterranean. Zoology in the Middle East, 61, 300-317.

Lewison, R.L., Crowder, L. B., 2007. Putting longline bycatch of sea turtles into perspective. Conservation Biology, 21, 79-86.

Lucchetti, A., Sala, A., 2010. An overview of loggerhead sea turtle (Caretta caretta) bycatch and technical mitigation measures in the Mediterranean Sea. Reviews in Fish Biology and Fisheries, 20, 141-161.

Lucchetti, A., Vasapollo, C., Virgili, M., 2017a. An interview-based approach to assess sea turtle bycatch in Italian waters. PeerJ, 5, e3151.

Lucchetti, A., Vasapollo, C., Virgili, M., 2017b. Sea turtle bycatch in the Adriatic Sea set net fisheries and possible hot-spot identification. Aquatic Conservation Marine and Freshwater Ecosystems, 27, 1176-1185.

Lucchetti, A., Angelini, V., Furii, G., Pari, S., Vasapollo, C., Virgili, M., 2018. Evidence of loggerhead seaturtle (Caretta caretta, Linnaeus, 1758) injuries caused by Rapido (beam) trawling in the Mediterranean. Herpetological Journal, 28, 134-136.

Lucchetti, A., Bargione, G., Petetta, A., Vasapollo, C., Virgili, M., 2019. Reducing Sea Turtle Bycatch in the Mediterranean Mixed Demersal Fisheries. Frontiers in Marine Science, 6, 387.

Margaritoulis, D., Argano, R., Baran, I., Bentivegna, F., Bradai, M.N. et al., 2003. Loggerhead turtles in the Mediterranean: present knowledge and conservation perspectives. p. 175-198. In: Biology and Conservation of Loggerhead Sea Turtles. Bolten, A.B., Witherington, B.E. (Eds). Smithsonian Books, Washington, DC.

Seminoff, J.A., 2004. Chelonia mydas. The IUCN Red List of Threatened Species 2004: e.T4615A11037468.https://dx.doi.org/10.2305/IUCN.UK.2004.RLTS.T4615A11037468.en. (Accessed 3 June 2020).

Tomas, J., Gozalbes, P., Raga, J.A., Godley, B.J., 2008. Bycatch of loggerhead sea turtles: insights from 14 years of stranding data. Endangered Species Research, 5, 161-169.

Turkozan, O., Ozdilek, S.Y., Ergene, S., Ucar, A.H. et al., 2013. Strandings of loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtles along the eastern Mediterranean coast of Turkey. Herpetological Journal, 23, 11-15.

Vasapollo, C., Virgili, M., Petetta, A., Bargione, G., Sala, A., Lucchetti, A., 2019. Bottom trawl catch comparison in the Mediterranean Sea: Flexible Turtle Excluder Device (TED) vs traditional gear. PLoS ONE, 14 (2), e0216023.

Virgili, M., Vasapollo, C., Lucchetti, A., 2018. Can ultraviolet illumination reduce sea turtle bycatch in Mediterranean set net fisheries? Fisheries Research, 199, 1-7.

Wallace, B.P., Tiwari, M., Girondot, M. 2013a. Dermochelys coriacea. The IUCN Red List of Threatened Species 2013: e.T6494A43526147. https://dx.doi.org/10.2305/IUCN.UK.2013-2.RLTS.T6494A43526147.en. (Accessed 3 June 2020).

Wallace, B.P., Kot, C.Y., DiMatteo, A.D., Lee, T., Crowder, L.B. et al., 2013b. Impacts of fisheries bycatch on marine turtle populations worldwide: toward conservation and research priorities. Ecosphere, 4, 1-49.


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