Climate Change Increases Risks for Whale Sharks Due to Shipping Lanes
Whale sharks, the largest fish, face increased risks of deadly collisions with ships due to climate change warming ocean waters. A study suggests that without significant action to curtail fossil fuel consumption, the risk of such encounters could rise by 43 percent by 2100. Efforts to enforce speed limits for ships in high-risk areas could reduce whale shark casualties significantly, emphasizing the need for immediate conservation actions.
Climate change poses a grave threat to whale sharks, the largest fish in the ocean, as warming waters and busy shipping lanes increase their risk of fatal collisions with cargo vessels. A recent study published in Nature Climate Change reveals that if fossil fuel consumption continues unabated, the likelihood of these deadly encounters could rise by up to 43 percent by 2100. Utilizing 15 years of satellite data tracking 348 whale sharks, researchers discovered a significant overlap between the sharks’ movements as they seek cooler waters and major shipping routes. Furthermore, whale shark populations have declined over 50 percent in the last 75 years, primarily due to overfishing and the current climate crisis complicates their plight.
Despite protective measures being implemented in many areas, the consistent decline in whale shark numbers remains concerning. A previous study indicated nearly a 92 percent overlap between the routes of these gentle giants and busy shipping lanes, with some sharks vanishing upon entering these areas, likely due to collisions with fast-moving vessels. These sharks are particularly susceptible to such encounters due to their slow swimming and behavior of feeding near the surface.
In response to this alarming trend, researchers suggest a practical solution: implementing speed limits for industrial ships in high-risk collision areas, akin to existing regulations for protecting endangered whale species, such as the North Atlantic right whale. The findings underscore the possibility of significantly reducing whale shark fatalities by decreasing vessel speeds to below 10 knots. Moreover, minor adjustments to shipping routes could further mitigate this problem. These insights highlight the pressing need for actionable measures to safeguard whale sharks’ future in the face of both climate change and human impact.
Whale sharks have been protected under various national and international regulations due to their declining populations, which have dropped more than 50 percent in the past seventy-five years primarily due to global overfishing in the late 20th century. Despite these protections, their numbers continue to dwindle, raising concerns about the effectiveness of current conservation efforts. Climate change adds an additional layer of risk, as shifting ocean temperatures compel whale sharks to migrate toward cooler waters, placing them in direct conflict with shipping lanes, thus leading to fatal encounters with cargo vessels.
The evidence presented in the study highlights the critical intersection of climate change and anthropogenic factors affecting whale sharks. Urgent action is needed to implement speed restrictions for vessels in these designated areas to reduce collisions. The potential to save this endangered species lies in the proactive measures that governments and industries can adopt. As climate change continues to exacerbate existing threats to marine wildlife, it is imperative that we leverage the available data and tools to change the trajectory for whale sharks and other vulnerable species.
Original Source: www.conservation.org
