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!

Giant whales and collapsing cod stocks: Thursday Afternoon Dredging, March 29th, 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!

Migrating mullet and expanding garbage patches: Thursday Afternoon Dredging, March 22, 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!

In South Louisiana, Seafood Means Hope

This blog post and photo slideshow was created during OCEANDOTCOMM, an ocean science communication event, and supported by the Louisiana Universities Marine Consortium (LUMCON) The theme of OCEANDOTCOMM was Coastal Optimism. Photos were contributed by our lead photographer, Rafeed Hussain/Ocean Conservancy, with additions from other OCEANDOTCOMM attendees, including Melissa Miller, Samantha Oester, Susan Von Thun, Solomon David, Rebecca Helm, and Alexander Havens.

A sign at the Bait House in Chauvin, Louisiana. Photo by Rafeed Hussain / Ocean Conservancy

In many ways, South Louisiana is seafood- a trip here isn’t complete without eating some gumbo, oysters, or crawfish. Only one state (Alaska) lands more seafood than Louisiana’s 1.2 billion pounds a year (as of 2016). As of 2008, one in 70 jobs in the whole state is tied to fishing or related industries. According to the Louisiana Seafood Marketing and Promotion Board, “when you choose Louisiana seafood, you’re ensuring that your purchase benefits an American community and a way of life.”

When we visited Terrebonne Parish, home to nearly 20 percent of all commercial fishing license holders in Louisiana, we found that fishing means more to the people of this community than food and jobs. Here in South Louisiana, fishing is a vital part of the vibrant local culture and community pride. In a region that’s been devastated by hurricanes and oil spills, fishing is also a source of something more important: hope.

Below, you’ll hear what fishing means to South Louisiana’s fishing communities through the voices of a former shrimper, the owner of a grocery store that has served the town of Chauvin for more than a century, and representatives of a local Native American tribe. You’ll also get a glimpse into this beautiful part of the world through a photo slideshow. Together, this paints a picture of communities that have overcome unimaginable struggle, but still look forward to the future, in no small part because of the riches of the sea.

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Endangered turtles and fish venom: Thursday Afternoon Dredging, March 15, 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 megalodon tooth! Here are 5 things to know about megalodon.

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.

The first month’s reward comes from one of the most (in)famous sharks of all time, Carcharocles megalodon! The first 3D printed Patreon reward is a meg tooth, an exact copy of the meg tooth that has been used to educate thousands of students at UBC’s Beaty Biodiversity Museum!

The original tooth

Here are some things to know about Carcharocles megalodon!

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