Sharks and rays are one of the most ancient vertebrate groups, as well as one of the most endangered.
Researchers still know very little about many shark and ray species and the environments in which they live, particularly rare species and those that dwell in remote areas, where resources and capacity for conducting study and monitoring are scarce.
To address these knowledge gaps, Francesco Ferretti, an assistant professor in the Department of Fish and Wildlife Conservation in the College of Natural Resources and Environment, polled an international team of scientists and practitioners to take a pulse of the greatest issues that are present in shark research, marine conservation, and fisheries science.
“In science, it is very important to know things. But it is even more important to understand what you don't know. If you are able to do that, then you can focus your efforts more effectively in that direction," said Ferretti, who is an affiliate of the Center for Coastal Studies and the Global Change Center, both of which are housed in the Fralin Life Sciences Institute. “In our review, we found that key opportunities for addressing these threats and conserving these crucially important animals come from technological advances, international coordination of research and action, and multi-stakeholder collaboration.”
Their review was published in Endangered Species Research.
Ferretti and his colleagues selected 20 of the most pressing topics in research and conservation of shark and ray populations. The issues ranged from their ecology to the threats they face and management and conservation actions that need to be taken.
A total of 47 experts from 35 institutions and 13 countries came together to offer their current understandings, knowledge gaps, and what is, in their opinion, the way forward.
“Sharks and rays are an amazing group of animals that occupy all oceanic and coastal ecosystems of our planet," said Fiorenza Micheli, co-director of Stanford Center for Ocean Solutions and co-author of the study. “This extraordinary diversity and key ecological functions and services are at risk from many pressures — overexploitation, pollution, habitat loss, and climate change.”
The importance of sharks and rays in coastal marine ecosystems cannot be overstated. These animals are the top predators in the food chain, and they are able to influence the abundance of prey populations, shape the structure and function of marine communities and food webs, and bridge distant ecosystems together.
Unfortunately, these animals are particularly vulnerable to exploitation because of two reasons: their patterns of survival — such as late maturation and low offspring numbers — and widespread exposure to human-caused pressures.
“We have learned a great deal about some of the larger and more charismatic shark species and in many parts of the world have established effective ongoing monitoring programs,” said Salvador Jorgensen, a marine ecologist and researcher at the University of California, Santa Cruz, and a lead author on the study. “While we build on those successes, it is imperative that we also shift our focus to lesser-known but equally important shark and ray species, transfering lessons learned to remote habitats and rare species that have escaped scientific study but not the increasing pressures of human impact.”
To help solve this issue of data scarcity, Ferretti’s lab is leveraging our fascination with sharks and infatuation with social media.
Ferretti's lab is using a new and intriguing piece of technology called sharkPulse to help solve the scarcity of shark data. This is a crowdsourcing platform supported by seed funding from the Global Change Center able to transform all images or media found on social networks of shark occurrences into data that can be used for analysis.
The lab is tapping into social media platforms such as Facebook, Twitter, Instagram, and Flickr. Additionally, sharkPulse allows citizen scientists to share their own images from their mobile phones and validate the streams of data that are coming from the social media platforms.
With permission of citizen scientists and access to their geolocation information and timestamps, researchers will be able to conduct habitat modeling analysis, perform trend and distribution analyses, and plan more targeted field investigations.
Last year, Feretti used distribution models based on sharkPulse and other historical sighting record data on an expedition in the Sicilian Channel to study the area's incredibly rare great white shark population. Great white shark populations have plummeted as a result of overfishing in the Mediterranean, raising the question of how many animals remain. They intend to return to the Mediterranean in the spring of next year to tag and follow more of the elusive animals.
But understanding more about shark behavior and habitats is more than just filling in information gaps; it can also help us safeguard sharks and ourselves from unintentional attacks.
“By understanding more sharks, we can also mitigate the risk of interacting with these sharks because we know seasons where they are active and the seasons when they are absent,” said Ferretti. “You don't go in the northern part of California and surf in November, because that's a hot spot for white sharks. If you want to reduce your risk, go down to Southern California, where there are younger sharks and smaller sharks with lower risk for them to interact in an injurious way.”
The review will be especially beneficial to aspiring scientists and researchers who want to stay up to date on the newest technologies and improve their studies on sharks.
"Reviews such as this are an incredible way to synthesize findings from various studies and identify patterns, which may be particularly useful in understanding the biology and ecology of some lesser-studied species of sharks and rays," said Brendan Shea, a Ph.D. student in the Ferretti lab. "Ultimately, we hope this review serves as a road map for future work by identifying the critical knowledge gaps in shark and ray science as well as some of the most promising approaches and technologies researchers can use to pursue them.”
Endangered Species Research