A lesser electric ray. Photo credit: Brandi Noble, NOAA Fisheries Service
The lesser electric ray, a small sand-dwelling ray that lives from North Carolina to Brazil, has been considered one of the most endangered marine fish on Earth. A 2005 paper reported that 98% of these rays had been wiped out, a decline attributed to shrimp trawling bycatch. This paper resulted in these animals getting classified as IUCN Red List “Critically Endangered,” the highest risk category for any species that is still found in the wild.
A new paper published today in the journal Endangered Species Research shows that these rays are in much better shape than previously believed. “There is no evidence of a decline in the relative abundance of lesser electric rays,” said Dr. John Carlson, a NOAA Fisheries Service Research Biologist and lead author of the new paper.
Bonnethead sharks, one of the smallest members of the hammerhead shark family Sphyrnidae, have a special place in my heart. For many years, the avatar I used for science communication efforts, including posts on this blog, was a picture of me with a bonnethead.
Remember this avatar? That’s a bonnethead (on the left).
These sharks, which can grow up to about 5 feet long, are found throughout North, Central, and South America. However, new research by Fields and friends suggests that they may actually be a species complex, not a true species. “A species complex is a group of distinct species that are incorrectly classified as one species because they look very similar to one another,” explained Dr. Demian Chapman, an Associate Professor of Biology at Florida International University and a co-author on this new study. “A great example is the white spotted eagle ray (Aetobatus narinari) that was once thought to be one, globally distributed species, but now has been shown to be a group of very similar-looking species, each of which lives in a particular region.”
The fam attending my dissertation defense
After a little more than 5 years of hard work, I’ve officially completed my Ph.D.! You can read my dissertation (“An Integrative and Interdisciplinary Approach to Shark Conservation: Policy Solutions, Ecosystem Role, and Stakeholder Attitudes”) online here in its entirety.
In case there are some among you who don’t really want to read a 281 page dissertation but are curious about what I found, I’ve prepared this blog post to summarize my key conclusions. (Note: this does not include every conclusion. Some are aggregated together, and some more technical conclusions are omitted for this summary).
Paul J. Clerkin is a graduate researcher at the Pacific Shark Research Center of Moss Landing Marine Laboratories in Moss Landing, California. Clerkin specializes in rare and deep-sea chondrichthyans and is focusing on new species descriptions and life histories of poorly understood sharks species. His thesis work is with Dr. David A. Ebert studying sharks encountered during two surveys in the Southern Indian Ocean in 2012 and 2014, a total of 126 days at sea. He has also conducted research for other projects aboard ships in the Bering Sea, South East Atlantic, Philippine Sea, and across the Pacific. He was featured in the “Alien Sharks” series on Shark Week.
This week, Travel Channel is airing a pilot for my new series, Deep Sea Mysteries (“like” our page on Facebook!). In the course of research, I visit extraordinary fishing communities to find and study rare, poorly known and even undescribed species. This show is the first of its kind, different from the Shark Week programs I’ve done in the past. It continues a focus on sharks and other deep-sea animals, but is notably (and pleasantly) more educational. There are more species, more facts, more science, and an emphasis on conservation effort.
Also, as a travel show, the series combs through the beautiful regions, interesting people and unique stories behind each expedition.
Seb Pardo is a biologist currently doing a PhD at Simon Fraser University in Canada. He is broadly interested in the biology, ecology, and conservation of sharks and rays. At present, his research is focused on borrowing tools from evolutionary biology to predict the biology and extinction risk of poorly studied sharks and rays. By using these data-poor methods, he hopes to make the most out of currently available data to inform policy decisions relevant for the sustainable management of sharks and rays. His twitter handle is @sebpardo
Chilean Devil Rays (Mobula tarapacana) swimming in the Azores.
© Daniel Van Duinkerken — http://danielvandphoto.com — Instagram: daniel.van.d
Rays rarely get the same amount of attention as sharks do. Perhaps the most notable exception are the manta rays (genus Manta), which are charismatic, filter-feeding rays that inhabit warm waters throughout the world’s oceans. Their closest relatives, the devil rays (genus Mobula), are not nearly as “famous” — even though they are the only other members of the family Mobulidae. There are nine species of devil rays found throughout the world’s tropical and temperate oceans, and while they are smaller than mantas (only reach over 3 metres in width), devil and manta rays are so similar that they are sometimes confused with each other. Because devil rays garner less public interest, the are very few studies on their basic biology and ecology, hindering our ability to assess their status.
Devil and manta rays face similar threats. Both are often caught as bycatch in industrial and artisanal fishing operations, which may result in considerable mortality even after being released. On top of this, there has been an increase in the international demand for their gill plates, which are used a health tonic in Chinese medicine. This has increased targeted fishing and bycatch retention in many places around the world. However, because of the lack of information on devil rays, it is very difficult assess whether this level of catch and trade is sustainable. This is the key question we set out to answer.
Erin Dillon is a PhD student at UC Santa Barbara studying how shark communities on coral reefs have changed over time. She graduated from Stanford University in 2014 with a B.S. in Biology and Honors in Marine Biology. Erin spent the following two years working with Dr. Aaron O’Dea as a fellow at the Smithsonian Tropical Research Institute in Panama, where she started exploring dermal denticles preserved in sediments as a paleoecological tool to reconstruct shark communities. She aims to develop this technique further as part of her dissertation to establish quantitative shark baselines and investigate spatial and temporal variation in shark assemblages on reefs. To do so, she has now set her sights on Curaçao, which is located in the southern Caribbean. There, she will work on validating the tool, explore differences in denticle assemblages between reef habitats, and provide estimates of relative shark abundance in data-limited parts of the island. Sharks are notoriously difficult to census, and it can be difficult to protect something that we rarely see. Therefore, the information provided by denticle assemblages extracted from reef sediments has critical implications for shark conservation, both in the Caribbean and worldwide. Erin is raising funds until September 22nd as part of Experiment’s Coral Reef Grant Challenge to unravel a pre-historical baseline of Caribbean sharks.
Sharks are important players on coral reefs. However, understanding the temporal and spatial dynamics of shark communities and how they are affected by human activities is challenging. Surveys and fisheries catch statistics reveal that shark populations worldwide have suffered significant declines over the past several decades due to overfishing and habitat degradation. But how many sharks should there be in a healthy coral reef ecosystem? The answer to this question is locked in the past. To address this issue, we turn to the recent fossil record to uncover clues about the sharks that used to roam the reefs of lore and paint a picture of how their communities have changed over time.
The American Elasmobranch Society is the world’s oldest and largest professional association of shark and ray scientists
The American Elasmobranch Society, the world’s oldest and largest professional society focusing on the scientific study and management of sharks and their relatives, is now welcoming applications for the 2nd year of our Young Professional Recruitment Fund diversity initiative. Awardees will be given one year of Society membership, in addition to specialized professional development training, mentorship, and networking opportunities specific to their needs as scientists and professionals from developing nations or historically underrepresented minority groups.
Applications, which can be found here, are due by 5 P.M. U.S. eastern standard time on Tuesday, November 15th. All winners will be notified by Friday, December 16th.
To be eligible for a Young Professional Recruitment Fund award, applicants must fill out the application and demonstrate that they:
A great white shark nursery in the North Atlantic that was discovered in 1985 south of Cape Cod in the waters off Montauk, New York has received renewed attention due to the increased activity of white sharks off cape cod in recent years. The nursery was first documented in 1985 by Casey and Pratt who deduced the presence of a nursery based on the number of juvenile sightings and landings in the area. This work was followed up recently by OCEARCH (an organization dedicated to generating scientific data related to tracking/telemetry and biological studies of keystone marine species such as great white sharks), which tagged and tracked nine infant great whites to the nursery, located a few miles off Montauk.
Great White Shark. Image courtesy animals.NationalGeographic.com
Photo of a great white shark in Mexico by Terry Goss, WikiMedia Commons. http://commons.wikimedia.org/wiki/File:White_shark.jpg
Joshua Moyer is an ichthyologist specializing in the evolution, biodiversity, and morphology of sharks and their relatives, collectively known as elasmobranchs. He is a member of the American Society of Ichthyologists and Herpetologists (ASIH) and the American Elasmobranch Society (AES). He has co-authored multiple scientific articles about shark teeth and their roles in understanding elasmobranch evolution. Joshua earned his Masters of Science in Ecology and Evolutionary Biology at Cornell University and teaches evolutionary biology at Ithaca College. Joshua also routinely lectures in courses on marine biology, vertebrate biology, and elasmobranchs. He has co-taught courses in shark biology in the field, laboratory, classroom, and most recently the online edX.org course “Sharks! Global Biodiversity, Biology, and Conservation.”
Whenever I tell someone that I study sharks I can see their imagination shift into high gear. Their eyebrows go up, their mouths make an intrigued smile, and I’m usually asked whether I’ve gone swimming with sharks or if I’ve ever been bitten by one. Yes, I’ve been in the water with sharks. No, a shark has never bitten me (although I did drop the jaw of a Mako shark on my arm once – that left an interesting scar). I’ve also gone on shark tagging trips and many spent days as an undergraduate documenting the social behaviors of sharks in aquaria. Those are what I call my “dinner party stories.” They’re the anecdotes people expect to hear from a shark biologist. I’m frequently happy to oblige. However, I’d be remiss if I didn’t acknowledge that oceanic adventures are not essential to being a shark biologist, and they’re no substitute for curiosity and educated observation. In other words, you may see a shark, but you need to know how to really look at it – how to study it.
President, Shark Advocates International
Sonja Fordham founded Shark Advocates International as a project of The Ocean Foundation in 2010 based on her two decades of shark conservation experience at Ocean Conservancy. She is Deputy Chair of the IUCN Shark Specialist Group and Conservation Committee Chair for the American Elasmobranch Society, has co-authored numerous publications on shark fisheries management, and serves on most of the U.S. federal and state government advisory panels relevant to sharks and rays. Her awards include the U.S. Department of Commerce Environmental Hero Award, the Peter Benchley Shark Conservation Award, and the IUCN Harry Messel Award for Conservation Leadership.
A new study confirming the mysterious deepsea Greenland Shark as the world’s longest lived vertebrate has made huge news in the last few days – from Science News and BBC to People magazine and the Wall Street Journal. While some scientists are questioning whether these sharks live quite as long as estimated (392 years ± 120), most agree they could well live for a century or two and – as a result — are particularly vulnerable to overfishing. Experts also warn that risks to Greenland sharks may be increasing as melting sea ice changes Arctic ecosystems and makes fishing in the region more feasible. Study authors are among those urging a precautionary approach to the species’ conservation. In other words, an incomplete picture of status and threats should not be used as an excuse for inaction. So what might be threatening Greenland sharks today, and which upcoming policy opportunities might warrant consideration, given worldwide interest in these jaw-dropping findings? To come up with some ideas, I first took a look back.