A case study on blast fishing in illegal small scale fisheries in the Aegean Sea: Catch composition and observed external and internal abnormalities for 18 Osteichthyes fish species.

Blast fishing is an illegal, ecologically destructive fishing method, fatal for many fish species at large scales. Blast fishing using dynamite is preferred by the fishers, especially small scale fisheries in Turkey, as it requires minimal effort but still results in higher catches. In the current study, demonstration of 20 controlled real-time blasting results involves species composition, size of fish, catch rates, catch composition, commercial/discard ratios, CPUE estimates and clinical observations of external and internal abnormality symptoms of fish species. Blasting trials were carried out with special permission in limited numbers because of its harmful effect. The collected data was tested using PRIMER v6 and diversity indices were also analysed. For the similarity between collected species cluster analysis was used to examine the stability of the results. Multidimensional scaling (MDS) was also applied for the assessment of fish species in the catch. A total of 1014 individuals (63.8 kg) were collected and 18 fish species belonging to seven families were examined. According to laboratory examinations, it was found that blasting caused different external and internal abnormality symptoms in the sampled fish species during the study.

Toward a decade of ocean science for sustainable development through acoustic animal tracking.

The ocean is a key component of the Earth's dynamics, providing a great variety of ecosystem services to humans. Yet, human activities are globally changing its structure and major components, including marine biodiversity. In this context, the United Nations has proclaimed a Decade of Ocean Science for Sustainable Development to tackle the scientific challenges necessary for a sustainable use of the ocean by means of the Sustainable Development Goal 14 (SDG14). Here, we review how Acoustic animal Tracking, a widely distributed methodology of tracking marine biodiversity with electronic devices, can provide a roadmap for implementing the major Actions to achieve the SDG14. We show that acoustic tracking can be used to reduce and monitor the effects of marine pollution including noise, light, and plastic pollution. Acoustic tracking can be effectively used to monitor the responses of marine biodiversity to human-made infrastructures and habitat restoration, as well as to determine the effects of hypoxia, ocean warming, and acidification. Acoustic tracking has been historically used to inform fisheries management, the design of marine protected areas, and the detection of essential habitats, rendering this technique particularly attractive to achieve the sustainable fishing and spatial protection target goals of the SDG14. Finally, acoustic tracking can contribute to end illegal, unreported, and unregulated fishing by providing tools to monitor marine biodiversity against poachers and promote the development of Small Islands Developing States and developing countries. To fully benefit from acoustic tracking supporting the SDG14 Targets, trans-boundary collaborative efforts through tracking networks are required to promote ocean information sharing and ocean literacy. We therefore propose acoustic tracking and tracking networks as relevant contributors to tackle the scientific challenges that are necessary for a sustainable use of the ocean promoted by the United Nations.

Shipwrecks are not the ultimate attracting features in a natural marine environment-the case of Karaburun, Turkey.

Shipwrecks attract divers. Therefore, decommissioned marine vehicles are used as artificial reefs for recreational diving tourism around the world. We examined divers' attitudes towards shipwrecks and their function as an ecological enhancers. The study was carried out in the Karaburun Peninsula, Turkey, where two passenger ships were sunk as artificial wreck reefs to attract diving tourism. Using a questionnaire survey accompanied by face-to-face interviews, of both certified divers and non-certified discovery divers we collected information about divers reefs preferences, perception of artificial reefs as well as their socio-demographic characteristics, dive experiences etc. Differences in divers' wreck (historical or artificial) and reef preferences (natural reefs or artificial wrecks) were analyzed with the Mann-Whitney U test. Overall, divers held the position that artificial wreck reefs provide ecological benefits on fish diversity and stocks (p < 0.05), and experienced divers supported this position more that novice ones. However, experience and number of annual dives did not affect this notion. Non-certified respondents were mostly neutral towards the ecologic and management statements. However, the majority of divers (84%) preferred to dive on natural reefs rather than on shipwrecks. Similarly, most of them (83%) preferred diving to historical shipwrecks which sank in wars or accidents, and not on ships intentionally sunk as attractions. These findings, which are in line with previous literature, put a question mark on the growing practice of sinking nearly any ship to create diving attractions.