Plastic Free Fish, Chainsaw Lobsters, and Artificial Horseshoe Crab Blood: Thursday Afternoon Dredging, May 17th 2018

Cuttings (short and sweet): 

Spoils (long reads and deep dives):

Please add your own cuttings and spoils in the comments!

If you appreciate my shark research and conservation outreach, please consider supporting me on Patreon! Any amount is appreciated, and supporters get exclusive rewards!

Seafaring neanderthals and switchblade fish: A mega Thursday Afternoon Dredging, May 10th, 2018


After two weeks off, we’re back and bigger than ever!

Cuttings (short and sweet): 

Spoils (long reads and deep dives):

Please add your own cuttings and spoils in the comments!

If you appreciate my shark research and conservation outreach, please consider supporting me on Patreon! Any amount is appreciated, and supporters get exclusive rewards!

Ocean apps and beluga migrations: Thursday Afternoon Dredging, April 19th, 2018

Cuttings (short and sweet): 

Spoils (long reads and deep dives):

Please add your own cuttings and spoils in the comments!

If you appreciate my shark research and conservation outreach, please consider supporting me on Patreon! Any amount is appreciated, and supporters get exclusive rewards!

This month’s 3D printed reward is a horn shark and horn shark egg case!

I recently unveiled a new tier of Patreon rewards: 3D printed shark and ray models! For $17 per month, you will get a monthly 3D printed educational model of different shark or ray parts in the mail, and you’ll be supporting my efforts to provide these models to schools for free.

This month’s reward is a model of a horn shark (Heterodontus francisci) and a horn shark egg case!

It comes from Alex Warneke, the Science Education Coordinator of Cabrillo National Monument! “”Using 3D printing technology has not only changed the way we educate the public, but it has broadened our perspective on what is possible in National Parks,” Alex told me. “We have been able to connect students to nature from an entirely different angle and provide them the tools and context they will need to succeed as scientists of the next generation.” This individual horn shark comes from the ichthyology collection at Cabrillo, and has been used for public education as well as research. The egg case is one of many that wash up on California beaches.

The original horn shark specimen and the 3D model of it, courtesy Alex Warneke, Cabrillo National Monument

Learn more about horn sharks and their egg cases below!

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An open letter to the Florida Fish and Wildlife Conservation Commission on revising land-based recreational shark fishing regulations

Note: The Florida Fish and Wildlife Conservation Commission (FWC) is holding a public meeting on April 25th which will include the issue of land-based recreational shark fishing. Part of my dissertation research focused on this topic, so I am submitting expert testimony, but since I no longer live in Florida I am submitting it remotely. I am sharing my testimony here. Anyone else who is interested in attending the meeting in person (Fort Lauderdale Marriott on April 25th), or submitting testimony remotely, is free to quote my talking points below if the appropriate references are cited. 

Dear Chair Rivard, Vice Chair Spottswood, Commissioner Kellam, Commissioner Lester, Commissioner Nicklaus, Commissioner Rood, and Commissioner Sole of the Florida Fish and Wildlife Conservation Commission (FWC),

My name is Dr. David Shiffman, and I studied land-based shark fishing in Florida as part of my Ph.D. dissertation at the University of Miami’s Abess Center for Ecosystem Science and Policy. This research was published in the peer-reviewed scientific journal Fisheries Research (here’s a link to an open access copy) and covered in major media outlets including National Geographic, Nature, and the Miami Herald. Accordingly, I would like to provide expert testimony for your April 25th public hearing on this topic. Since I no longer reside in Florida I am submitting this testimony remotely. As a conservation biologist who spent years studying harmful practices among some elements of the land-based Florida shark fishing community, I am grateful to see FWC holding a public meeting that includes this important issue, and I am grateful for the opportunity to contribute.

Overall, the scientific evidence is clear and overwhelming that while many anglers are rule-following and conservation-minded, many common land-based shark fishing practices represent a significant conservation threat to threatened, protected shark species in Florida. Additionally, the evidence is clear and overwhelming that in many cases anglers are breaking existing laws and regulations, and that in some of those cases the anglers are aware that they are breaking the law and are explicitly stating that they don’t care. Finally, the evidence is clear and overwhelming that many of the arguments put forward by land-based anglers in support of the status quo are not argued in good faith, and are intentionally crafted to misrepresent the facts of the situation.

It is obvious to me, and to many expert colleagues with whom I have discussed this issue, that the FWC can and must do more to protect threatened sharks, building off of early successes that made Florida a leader in shark conservation. Specifically, the FWC can and must do more to regulate these harmful practices, enforce clear violations of existing regulations, and educate anglers about these issues. Below I will elaborate on each of these points and propose specific regulatory, enforcement, and public education changes that can be made to protect sharks without significantly infringing on anyone’s rights. I will also counter several common arguments that are put forth by bad actors in the recreational angling community.

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Sea monsters and saving kelp: Thursday Afternoon Dredging, April 12, 2018

Cuttings (short and sweet): 

Spoils (long reads and deep dives):

Please add your own cuttings and spoils in the comments!

If you appreciate my shark research and conservation outreach, please consider supporting me on Patreon! Any amount is appreciated, and supporters get exclusive rewards!

Dear Shark Man, what’s the deal with those notches on shark tails?

Welcome to  Dear Shark Man, an advice column inspired by a ridiculous e-mail I received. You can send your questions to me via twitter (@WhySharksMatter) or e-mail (WhySharksMatter at gmail).


Dear Shark Man,

Why do sharks tend to have those little notches in their tail fin? Is it like an aerodynamic thing? If you were to fill it with more shark does something magic happen?
Sincerely,

Grateful in Georgia

Dear Grateful,

That’s a great question, and I didn’t know the answer! I reached out to an expert in the structure and function of shark fins, Dr. Brooke Flammang of the New Jersey Institute of Technology, to ask. Here’s what she told me.

“Sadly, there has not (yet) been a study focused on the fluid dynamics of the subterminal lobe (the flappy bit of tissue at the end of the tail, which moves freely because of the notch) of the shark tail. However, we can come up with a really good hypothesis about how it works!

Sharks that have the notch and the subterminal lobe are mostly in the order Carcharhiniformes (and also Squalus, which is the odd duck for everything). In Carcharhiniforms, as compared to, for example, Lamnids, the angle between the dorsal and ventral lobes is small, they have a low aspect ratio, and tails are more flexible. This suggests that Carchariniforms do not generate as much power with every tailbeat as Lamnids do.

Sharks with subterminal lobes tend to be slow-swimming, epibenthic/benthic/demersal dwellers. If you are swimming slowly in an undulatory fashion, you need to generate a considerable amount of force to maintain forward propulsion because you have less inertial benefit than when you are swimming quickly with a stiffer, more streamlined body. One way to increase force generation is to increase the momentum being added to the surrounding fluid – which is to say, you need to move more water away to push yourself forward.

The subterminal lobe adds surface area but is not stiff, lacking muscular control, and trails slightly behind the rest of the dorsal lobe during a fin beat. Because it trails behind, it extends the duration of time that fluid builds momentum before being shed from the tail (and thus generating thrust). Such passive thrust enhancement would likely only be effective at slow swimming speeds with more flexible tails, such as we see within the Carchariniformes. If you fill in the notch (and lose the flappiness of the subterminal lobe) you would decrease the efficacy of this enlarged area of flexible tissue in the tail considerably.”

Congratulations, Grateful, you’ve found a question that no one has explicitly studied, and given an expert an idea for a future project! We can only guess what would happen to  shark’s swimming behavior if this notch were filled in, and Dr. Flammang’s guess is as good as anyone’s!


If you appreciate my shark research and conservation outreach, please consider supporting me on Patreon! Any amount is appreciated, and supporters get exclusive rewards!

A scene-by-scene breakdown of the first trailer of “The Meg”

Yesterday, the trailer for “the Meg” was released online.  This movie is based on a popular book series that claims that megalodon is actually not extinct, just hiding. (I’m in the 4th book).


I have a love-hate relationship with movies like this, by which I mean that I love them and I hate myself for loving them. While movies like “Jaws” had a measurable negative effect on public perception of sharks, I don’t believe that more obviously ridiculous movies like SharkNado have a similar effect.  Jason Statham playing a marine biologist in a movie that includes Rainn Wilson? Sign me up.

If not for the people who believe that these movies are real and therefore decide to yell at marine biologists on twitter about it, I’d be all for this.  Let’s be totally clear here- Carcharocles megalodon is extinct, and here’s how we know. Shark Week lied to you about it. Actresses from this movie asking about it are not experts. This movie is completely fictional. You can certainly watch it and enjoy it, but please don’t cite it as evidence that a 50 foot long whale-eating shark that used to live in shallow coastal waters near what are now populated areas is not extinct.

Anyway, here is a scene-by scene breakdown of what’s in the first trailer. From it, we can tell that this is an action-packed movie with a great cast that does not stick too closely to the books, and is also not particularly interested in scientific accuracy even with respect to issues unrelated to the “giant extinct animals are actually not extinct”central conceit.

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Thoughts on the Sustainable Shark Fisheries and Trade Act

A few weeks ago, H.R. 5248, The Sustainable Shark Fisheries and Trade Act, was introduced into Congress. The purpose of this bill is to “encourage a science-based approach to significantly reduce the overfishing and unsustainable trade of sharks, rays and skates around the world and prevent shark finning,” according to a press release from Mote Marine Lab. 

Though the devil is always in the details, and I’ll get into those below, here is a general overview of how this would work. The Sustainable Shark Fisheries and Trade Act would direct NOAA Fisheries to evaluate the fisheries management practices of other shark and ray fishing nations. This is similar in principle to other things NOAA is already doing, and a similar role for NOAA was included in the 2010 Shark Conservation Act (but has yet to be implemented).

Nations that have sustainable fisheries management practices comparable to ours (or certain fisheries associated with those nations, even if other fisheries are less well managed) will get a formal certification of their sustainable management practices, and nothing will change for them. Nations (or fisheries) that are found to not have sustainable fisheries management practices comparable to ours will not be allowed to have those products imported into the US and sold in our markets until their management practices improve. In the meantime, they’ll have access to NOAA’s existing capacity building resources and expertise to improve their own practices.

I support much of what this bill is trying to do, but I have some significant concerns about some of the current phrasing and plan for implementation.

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Invisible squid and fish with glowing eye spikes: Thursday Afternoon Dredging, April 5th, 2018

Cuttings (short and sweet): 

Spoils (long reads and deep dives):

Please add your own cuttings and spoils in the comments!

If you appreciate my shark research and conservation outreach, please consider supporting me on Patreon! Any amount is appreciated, and supporters get exclusive rewards!