International study reveals those shark species most affected by fishing are most needed for healthy oceans.
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According to new research, shark conservation must go beyond simply protecting shark populations — it must prioritize protecting the ecological roles of sharks.
Over the past couple years an international team of shark scientists – funded by Shark Conservation Fund – conducted a groundbreaking analysis which reveals that those sharks most affected by fishing are most needed for healthy oceans.
The study, led by Florida International University published in the journal Science which illustrates the outsized role that sharks play in maintaining biodiversity and ecosystem health. We now have clear evidence that sharks play a far more complex and vital role than previously thought. They are not merely apex predators; sharks are ecosystem architects, nutrient transporters, and key players in maintaining the delicate balance of ocean biodiversity.
To truly safeguard our oceans, we need to adopt a more holistic approach that places sharks at the center of conservation efforts. This means we must fundamentally change how we manage shark populations, including a focus on preserving the role sharks play in marine ecosystems, not merely their abundance. This landmark study offers a blueprint for marine conservationists, philanthropists, policymakers, and the public for achieving and sustaining ocean health.
The largest sharks of many of the biggest species, such as tiger sharks and great whites, play an oversized role in healthy oceans, but they are often the most affected by fishing. The big sharks help maintain balance through their eating habits. Sometimes their sheer size is enough to scare away prey that could over-consume seagrass and other plant life needed for healthy oceans. Sharks can also help shape and maintain balance from the bottom-up. That means a variety of sharks in a variety of sizes are needed, yet their many and diverse contributions are under threat from overfishing, climate change, habitat loss, energy mining, shipping activities and more.
"Management should focus on restoring and maintaining sharks' ecological roles, not just their numbers,” comments co-author on the study and marine biologist, Dr Alison Kock of South African National Parks. “Well-enforced Marine Protected Areas (MPAs) that protect wide-ranging predators, with the help of modern technology, offer a promising solution. Engaging public support and incorporating local cultural values into management will also foster a greater appreciation for sharks and their essential ecological functions, especially in the face of widespread human impact on the oceans."
“Decreasing the extraction of sharks and rays is regarded as a primary tool to begin the recovery of sharks globally,” comments Senior Scientist Dr Jennifer Olbers of WILDTRUST. “Recognising this, it is essential for South Africa to adopt a multipronged approach for conservation of marine species. Protecting the ecological roles that sharks play in our waters will gain so much more for our shark conservation efforts. Protecting the species, their habitats and their life history stages, such as aggregation areas and gestation periods, is essential for their survival,” said Olbers.
Besides helping to maintain balance within the food web, reef sharks feed in offshore waters and bring nutrients back to the reef. Others move nutrients around that are used at the base of the food chain. Sharks can also serve as food for other species and even as scratching posts for fish to remove parasites. The problem is shark abundance has plummeted by 71 percent for oceanic species in the past 50 years. Populations of the top five reef shark species have been depleted by 63 percent. As their numbers plummet, their important roles in ocean health are also lost.
“It’s time to have a conversation about everything sharks are doing to maintain ocean health so we can better prioritize conservation efforts and have the biggest impact,” said Simon Dedman, researcher at Florida International University and lead author of the study.
The issue of shark conservation becomes all the more critical as global temperatures increase, leading some sharks to head into new areas where they can find the temperatures, they can thrive in.
“This study verifies what we’ve long suspected – sharks are critical to ocean health,” said Lee Crockett, executive director of the Shark Conservation Fund which funded the study. “This landmark study serves as confirmation that marine conservationists, philanthropists, policymakers, and the public alike need to recognize that sharks are keystone species that have a now-proven significant effect on marine environments.”
With the expansion of blue economy industries like aquaculture and tourism, people’s encounters with sharks will likely increase. Finding a balance that protects the sharks most needed for healthy oceans is hitting a critical point.
“National and international policy must focus on actions that rebuild populations and restore sharks' functional roles,” said Mike Heithaus, study co-author and FIU marine ecologist. “That requires action to increase both spatial measures like Marine Protected Areas and fisheries management measures like catch/size limits and gear limitations. If people want healthy oceans, we need healthy shark populations.”
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