A scientifically accurate list of the most endangered sharks in the world

One of the most common questions I get during my “ask me anything” sessions on twitter is “which species of sharks are the most endangered?” Whenever I can’t completely answer a question in a single tweet, I like to link to more information from a reliable source.

However, I’ve struggled to easily answer this question with a link, because much of the information out there about this particular question is incomplete, misleading, or just wrong.  Several online lists of the most endangered species of sharks* don’t actually include the most endangered species of sharks. Many of these lists could be re-titled as “the conservation status of some species of sharks I’ve heard of and could easily find pictures of” or “some random information I heard out of context about shark conservation.” Since there isn’t an easily accessible source of accurate information about this important shark science and conservation topic, I’ll make one myself. ( I should note here that I am referring only to true sharks, not to other chondrichthyans, even though other chondrichthyans in many cases face similar or worse threats. )

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Long live sharks and rays!

Alastair Harry is a fisheries science practitioner based in Perth, Australia. He assists in implementing ecosystem based fisheries management to support the sustainable use of wild-capture fish resources. He is a generalist and works across multiple areas including stock assessment, bycatch, and threatened species. He also holds an adjunct position at James Cook University and has a specific interest in the conservation and sustainable management of sharks and rays. 

In August I published a review paper entitled Evidence for systemic age underestimation in shark and ray ageing studies. In it I suggest that many sharks and rays live considerably longer than is currently recognised. This increased life expectancy isn’t due to medical advancements or a more nutritious diet (or even better fisheries management), but rather the result of ageing error.

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Gills Club Shark Tales: An online and in-person sharkstravaganza 19-20 September at NEAQ!

Note:  This post has been updated on 18 September 2017.  

Friends, Researchers, Countrywomen, lend me your ears!

The Atlantic White Shark Conservancy and New England Aquarium are hosting a completely free two-day event, 19-20 September, featuring an amazing line-up of shark scientists and enthusiasts, including:

Keynote Speakers:

Susan Goldberg – Editor in Chief of National Geographic Magazine

Wendy Benchley – Renowned global voice for shark protection and co-founder of the prestigious Peter Benchley Ocean Awards.

Gills Club Science Team Speakers:
Dr. Michelle Heupel – Australian Institute of Marine Science
Dr. Alison Kock – South African National Parks
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Background information on our land-based shark fishing paper

A photo used in this study showing a hammerhead shark taken completely out of the water. As with all photos used in this study, the angler’s privacy has been protecting by blurring out his face.

I have a new paper out on the conservation impacts of recreational shark fishing. The paper is called “fishing practices and representations of shark conservation issues among users of a land-based shark angling online forum,” and it is published in the journal Fisheries Research. If you don’t have institutional library access, you can read a copy of the paper here. The goal of this blog post is to provide background information on the study.

Journalists are free to quote or paraphrase information from this blog post. Additionally, I provide some suggested quotes below, and I am available for interviews about this paper (please contact me at WhySharksMatter at gmail).

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The Case Against Shark Fin Trade Bans

Photo credit: Jessica King, Marine Photobank

The United States Congress is considering a nationwide ban on buying, selling, or trading shark finsWhile several of my posts and tweets have briefly discussed my stance on such policies, I’ve never laid out my full argument in one post. Here is why I, as a shark conservation biologist, oppose banning the shark fin trade within the United States.  The short answer is that the US represents a tiny percentage of overall consumers of shark fin, but provide some of the most sustainably caught sharks on Earth, as well as important examples of successful management, to the world. This means that banning the US shark fin trade won’t reduce total shark mortality by very much, but will remove an important example of fins coming from a well-managed fishery while also hurting American fishermen who follow the rules. Also, a focus on these policies promotes the incorrect belief that shark fin soup is the only significant threat to sharks, and that addressing the tiny part of that problem locally represents the end of all threats. For the longer answer, read on. And for the case for shark fin bans, please see this guest post from Oceana scientist Mariah Pfleger.

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The Case for Shark Fin Trade Bans

Mariah Pfleger is a marine scientist at Oceana, an international marine conservation non-profit, advising both the responsible fishing and sharks campaigns. She graduated from Florida State University in 2012 where she studied coastal sharks and their relatives. In 2016 she earned her Master’s degree from the University of West Florida where she researched both coastal and deep-water sharks and rays. Mariah worked for 3 years as a field assistant, and during her Master’s an additional 3 years as a field manager, on the Gulf of Mexico Shark Pupping and Nursery Program. She has also conducted research using environmental DNA to detect rare and endangered sturgeon. Her twitter handle is @MariahPfleger.


The demand for shark fins is widely recognized as one of the major contributors to shark mortality around the world. However, solutions to decrease this demand are hotly debated, especially in the scientific community. Southern Fried Science and other websites have published opinions that debate the effectiveness of shark fin bans, but as a shark scientist working to implement this policy I would like to present the case for shark fin trade bans.

The conversation is newly relevant with the introduction of the Shark Fin Trade Elimination Act in the Senate on March 30th by Senators Cory Booker (D-NJ) and Shelly Moore-Capito (R-WV) and in the House on March 9th by Representatives Ed Royce (R-CA) and Gregorio Kilili Camacho Sablan (I-MP). If passed, the bill would ban the buying and selling of shark fins in the United States – thereby removing the United States from the global shark fin trade altogether. The bill is championed by Oceana, where I work as the scientist on the sharks campaign.

The demand for fins fuels finning – the act of slicing off a shark’s fins and dumping the body back into the ocean. The United States recognized this practice was a problem and implemented the Shark Finning Prohibition Act of 2000 followed by the  Shark Conservation Act (SCA) in 2010, which required that all sharks must be landed with their fins naturally attached (except for smooth dogfish, which can be landed under a fin-to-carcass ratio). However, according to the National Marine Fisheries Service, the United States is still importing fins from places like Hong Kong, China, New Zealand, the Netherlands, Spain, South Africa and Indonesia, to name a few. Not all of these countries have anti-finning laws, which means that the United States may be, and likely is, purchasing fins from finned sharks. Once in the United States market, there is no way to tell whether a fin came from a finned shark or not. By purchasing these fins, the United States is sustaining the demand for this unsustainable practice. Read More

Scientists deploy satellite tags on rarely studied sawsharks for the first time

An Australian research expedition has successfully deployed three satellite telemetry tags on sawsharks for the first time! These rarely-seen sharks have a toothy rostrum similar to a sawfish, but are true sharks while sawfish are rays. Sawshark rostrums also have sensory barbels, unlike the rostrums of sawfish. “This is actually a good example of convergent evolution where two distantly related species have adaptations that have converged to be very similar in looks and (purportedly) function,”said professor Jane Williamson, the head of the Marine Ecology Group at Macquarie University and the leader of this expedition. “Sawsharks probably use their rostrum in a similar manner to sawfish: as a tool for sensing and capturing prey, and possibly for self-defense.”

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Please don’t ride sharks, and other great tips from the new guide to responsible shark diving

Shark wildlife tourism* is a growing marine industry with big implications for shark conservation. While there are many competing definitions, generally shark wildlife tourism refers to SCUBA dive operators who offer trips that guarantee that you’ll see sharks, often through the use of bait or chum to attract sharks to the divers. This has become a contentious issue in marine science and conservation circles. That’s why last week’s news that  WWF, Project AWARE, and the Manta Trust released the first-ever guide to responsible shark and ray tourism best practices is so welcome. This thorough and well-researched guide guide is designed for dive operators who want to minimize their potential harm to sharks and rays while maximizing the potential conservation benefits of shark wildlife tourism.

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Rumors of the lesser electric ray’s demise have been greatly exaggerated

A lesser electric ray. Photo credit: Brandi Noble, NOAA Fisheries Service

The lesser electric raya 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.

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Bonnethead sharks, one of the smallest hammerheads, may actually be more than one species

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.”

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