На Кюрасао зафиксирован самый низкий уровень численности акул среди островов Карибского бассейна

WILLEMSTAD – Curaçao recorded the lowest relative shark abundance among the Dutch Caribbean islands included in a major study examining how human activity affects sharks and rays. Researchers found that Caribbean reef sharks were generally less common near heavily developed coastlines and areas experiencing intensive diving activity. The research analyzed 995 deployments of Baited Remote Underwater Video systems, or BRUVs, around Aruba, Bonaire, Curaçao, Saba, St. Eustatius and St. Maarten, as well as the largely uninhabited Saba Bank. The surveys were conducted between 2012 and 2017, with the results published in the Journal of Applied Ecology. For Curaçao, researchers conducted camera surveys at 164 locations in 2016. The island recorded an average relative shark abundance of 0.04 per sampling location, the lowest among all islands studied. By comparison, Aruba recorded 0.19, Bonaire 0.18, while St. Eustatius and the Saba Bank both recorded 0.47. The difference was also visible specifically for Caribbean reef sharks. Curaçao recorded an average relative abundance of 0.03, compared with 0.10 for Aruba, 0.14 for Bonaire and 0.20 for the Saba Bank. No nurse sharks were recorded during the Curaçao surveys. Human activity linked to fewer reef sharks According to the researchers, the distribution of Caribbean reef sharks was strongly associated with human activity. On inhabited islands, shark abundance declined as coastal development and actual diving activity increased around sampling locations. Caribbean reef sharks were also more frequently detected farther offshore and along the more exposed windward sides of islands. The findings suggest that reef sharks may avoid highly disturbed coastal areas even when the reefs themselves otherwise provide suitable habitat. Rays and nurse sharks appeared less sensitive to human presence. Their distribution was more closely associated with environmental characteristics such as water depth and reef structure. Researchers assessed human pressure using several indicators, including the amount of coastal development, the number of official dive sites and the intensity of diving and snorkeling. Recreational activity was estimated partly through geolocated underwater photographs posted on Flickr around the sampling sites. Interestingly, areas with more officially designated dive sites tended to have relatively more sharks. Researchers believe this is probably because established dive sites are often located at healthier or structurally complex reefs, which are also attractive habitats for sharks. The distinction, according to the study, appears to be between the existence of a dive site and the intensity with which that location is actually used. Figures are not a current shark census The researchers caution that the findings should not be interpreted as a current count of Curaçao’s shark population. Curaçao’s measurements date from 2016, while the islands included in the research were surveyed in different years. The study also measures relative abundance rather than estimating the total number of sharks living around each island. The method records the maximum number of individuals simultaneously visible during a camera deployment. Another important limitation for Curaçao is that researchers were unable to sample the island’s rugged eastern coastline because of weather conditions and difficult accessibility. That could be significant because the same research found Caribbean reef sharks more frequently along exposed coastlines and farther offshore. The study also establishes statistical associations rather than proving that coastal development or diving directly causes lower shark abundance. Fishing pressure, for example, was not independently measured. Researchers say other factors associated with developed coastal areas could also contribute, including pollution, sedimentation, reef degradation and changes in prey availability. Implications for Curaçao’s coastal policy The findings suggest that shark conservation cannot focus exclusively on marine protected areas or restrictions on fishing. Researchers argue that coastal development and tourism pressure should also be considered when governments develop marine and coastal spatial policies. Potential measures could include limiting or distributing the number of divers using sensitive locations, temporarily closing heavily pressured areas and establishing buffer zones around vulnerable reefs. However, the study does not establish a specific maximum number of divers that a reef can sustain. For Curaçao, the findings are particularly relevant given the concentration of development and tourism activity along much of the island’s southern coastline. The broader conclusion of the research is that human presence can significantly alter where large predators occur on coral reefs, even without directly catching or killing them. Coastal construction and intensive recreational use, the researchers argue, should therefore become a more explicit part of Caribbean reef-shark conservation policy.