Migratory patterns of Pacific Great Whites – as I suspected

A research study has come out today showing the migratory patterns of Pacific Great Whites. As I suspected and posted in my Body Surfing post, during the winter months these giant sharks migrate from between Hawaii and Baja to the Northern California hunting grounds. In fact, as recent as a few days ago, five Great White sharks were found to be underneath the Golden Gate Bridge.

Here is a chart detailing the Great Whites’ migratory patterns by month. Quite interesting.

If you don’t want to run into a Great White shark when you’re swimming, I’d stay out of the water in the winter months.

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Back from Hong Kong

I just got back from Hong Kong, and honestly, for most of the trip if I hadn’t actively been looking for shark fin, I may not have even seen any. This was a bit surprising, as I have been hearing a lot of commotion on the web about the prevalence of shark fin in the Chinese diet. At all the restaurants I visited, I may have only seen it once on the menu, and I can’t even guarantee that it was real fin. The picture above was taken in a mall in HK Times Square. I ate next door.

It was only when I was walking around the North Point neighborhood that I found shark fin. They were pretty small fins usually kept in glass food containers. The dried food stores had the fins, not normal grocery stores. The dried food stores sold random assortments of dried fish, mushrooms, herbs, and other produce/protein. The fins were always kept on the top shelf; I’m guessing to inhibit shoplifting. The fins are easily the priciest items in the store.

The fins in these pictures vary in price, depending on size and other attributes. The finds in these pictures I took in North Point are labeled at around $2,500 HKD for 1.25 oz. That’s $322 USD for 1.25oz, or over $4,000 USD per pound. I can’t think of any food costing that much, especially from a store like this. No wonder it’s not on many menus.

I spoke with some locals about shark fin soup, and they were receptive to my lectures about the dangers of shark finning. Honestly, I think they were more agreeable only because sharks fin isn’t something they eat on a regular basis, so it isn’t hard to give up. It’s mostly consumed at weddings or at a banquet of somebody trying to show off. I assume it’s more prevalent in mainland China, where the newly wealthy generations are looking for places to burn their money and always want to improve their social status.

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Shark conservationists piss me off

I’m heading to Hong Kong soon for a week for a wedding. The wedding is just one day, so I thought I’d look into using my time on the shark fin front and volunteer. I contacted a handful of shark and ocean conservation agencies, even ones supposedly based in Hong Kong. Here is the basic message I sent out:

I’ll be in HK for a week starting Thurs. Does the [agency name] have any local volunteer projects or other activities? I’m very into promoting regulation in shark fishing and education about the effects of over-fishing of sharks on the ocean’s ecosystem. Let me know, thanks.

You’d think organizations would be thrilled to get an offer for somebody to volunteer, right? You’d be dead wrong. I didn’t hear shit back. Not even a thanks but no thanks. Well, on Twitter I actually got one response, but it was just a “what can you do to get involved” general bs link to things like signing petitions or not ordering shark fin soup. Uhh, yea, I’m into sharks and write a blog, I know I can do those things. I thought by going to Hong Kong I’d actually have a chance to help at the root of the problem. Guess not.

That got me thinking. What are any of these shark conservation agencies doing? I started looking at their websites and such and began realizes that they weren’t doing much. Mostly they are going after the supply, since it’s more fun I’d imagine. They send their volunteers and researchers to exotic locales to go diving in tropical waters with sharks. Maybe they’ll tag a few or talk to some local biologists about the problem. They take pictures in their sunglasses and flip flops on boats or with a landed shark, post it on their website and that’s about it. Meanwhile 1 billion Chinese are still ordering shark’s fin soup and will never ever see anything about what these organizations have done.

This is a picture of January Jones being scared for sharks. Looks more like a photo shoot to me. I don’t mean to pick on January, I think it’s great she is bringing awareness to the cause. I don’t see any Chinese in this picture though. It looks more like the Bahamas to me.

That’s the problem in my eyes. All the activists are going after the suppliers and countries that allow finning. If they get poor third-world countries to ban shark finning, it really doesn’t effect the fin shark fin trade much because these countries are either too poor or too corrupt to enforce the laws. And, even if it did curb the illegal shark fishing in that country, that would only encourage fishermen to get more shark fin because the demand hasn’t changed. If the supply drops but demand increases or stays the same, then the prices will rise. The higher prices will motivate the fishermen all around the world to haul in more sharks because it means even more money.

The real solution is to go to the source, China, and promote education and restrictions there. If the demand is curbed, prices will drop and less fishermen will go after sharks because people won’t be buying. It’s basic economics.

I’m not saying to stop going after countries that allow shark finning practices, I just think that the root of the problem is being ignored. Send January Jones to China instead of to the beaches of the Caribbean.

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When I’m body surfing

I live in San Francisco, but I’m originally from Los Angeles and grew up going to the beach and swimming in the ocean. I love to body surf, but got spoiled in the warmer waters of So Cal, so I barely go in the water up north. In the summer when I visit my parents, I go to the beach every day and body surf. Sometimes between sets I’m just floating there, by myself, and admittedly my mind starts to wander.

At first it goes to the huge Malibu mansions looking back at me from the shoreline. “Damn, how do I get one of those!”. But then as I start to get cold from not moving too much my mind comes back to the water and I start thinking about what is going on in the water. I’d be lying if I said the thought of sharks never crosses my mind. I usually see dolphins when I’m out swimming in the waves, but when I first see a dolphin fin I do a double take just to make sure it’s the right shape. After that it’s all good and I get to swim with dolphins (or nearby at least), but before that I get a boost of adrenaline. I assume it’s my brain releasing it just in case I need to haul ass to shore.

Once October rolls around I know that Great White sharks are starting their migratory patterns north to Ano Nuevo and their rich hunting grounds. And I know they must pass by the beaches where I swim as they head north. After the summer I am hesitant to go in the water for that reason. Even though I love sharks and am a huge proponent of  protecting them, I know their power and that they can be dangerous. If I were ever bitten, or worse, I wouldn’t hold it against the shark, as I am in their habitat, but that doesn’t make me less wary.

The pictures at the top of this post are from early October of 2009, close to where I body surf in the summer. That’s a Great White breaching close to shore.

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Sharks have superpowers

Sharks have been on this planet for around 400 million year. Longer than any other major species. Over that lengthy period of time they have evolved to have more than your basic set of senses.

Of course they have the five major senses that we all have: smell, vision, touch, hearing, and taste (for human blood – lol). For sharks however, these senses have become superfied over their long existence. They also have an extra sense, or superpower, that allows them to sense fluctuations in electric fields, called electroreception.

It’s a shame that after 400 million years sharks are being wiped out because of another species indifference and selfishness to another species. We’ll probably never get to find out what the next stage in evolution has in store for sharks because humankind is set on eradicating them from the oceans. Imagine what kind of additional powers evolution has in store for us if we survive another 400 million years. Wouldn’t it be a shame if we never got a chance to find out because our gluttony and greed turned our planet into an uninhabitable rock covered in garbage?

Let’s take a closer look at the senses of a shark, shall we…

Smell: Now it’s a little exaggeration that a shark can smell blood from 50 miles away, or whatever the rumor is. Sharks do however have some crazy olfactory hardware that gives them super-smell. They can detect a bloody fish carcass in concentrations of less than 1 in 10 billion. That’s powerful, much more powerful than that of a human which is out-smelled by a rabbit by a factor of 20.

Once a shark picks up a scent trail it swims up the trail moving its head from side to side (which is its natural swimming motion). As its snout passes backwards and forwards through the scent trail it is able to determine the direction from which the odor is emanating. If the scent is lost or if the slick is too wide to use for navigation, the shark may swim forward in an exaggerated S pattern until it can pick up the direction again. After that it’s dinner time.

Vision: Most sharks possess excellent vision in low light conditions. The structure in the eye responsible for this is called the tapetum lucidum. This is a layer composed of mirrored crystals which lay behind the retina that can be adjusted to reflect light back onto the retina amplifying the strength of the image. Sharks share this ability with some nocturnal mammals and reptiles which require extremely sensitive vision to survive. Sharks do possess eyelids (both upper and lower) but they are fixed and unable to cover the eye.

White sharks have been seen to lift their heads out of the water far enough to get a look at their topside surroundings. This behavior has been witnessed in the presence of boats but possibly developed from the sharks desire to determine whether seals or sea lions are present in the area. It is unclear how well their eyes are adapted to above water vision.

Touch: Now this sense is pretty cool, and is different than what humans perceive as the sense of touch. The distant touch that is picked up through the lateral line canals, a series of interconnected canals run back from the back of the head all the way to the upper lobe of the tail in a distinct line. The canals open to the outside of the skin by means of tiny pores which allow water to penetrate. As water is displaced by the movement of creatures in the sharks surroundings, small waves are created which move away from the disturbances like ripples on a pond. As these waves pass over the hairs which line the lateral line canals the hairs are disturbed and send signals to the brain. The sharks own movement also creates these waves which then bounce off obstructions and return to the shark creating a kind of vibration echo map of its surroundings. The frequency or erratic nature of the vibrations indicate whether any animals in the area are sick or injured. Wow.

Sharks also possess a row of pores around the pectoral fins and gills, known as pit organs. These contain neuromast-like cells that are believed to aid the shark in the detection of temperature changes. Temperature may be an important factor for certain migratory sharks. It’s possible that some sharks may seek out particular temperatures where they know that a prey species is most likely to be present.

Hearing: The sharks hearing senses are not nearly as impressive as it’s other senses and is used mostly for balance. But so what! Who talks under water anyways?

Taste: Sharks have small pits in the lining of the mouth and throat that contain rod shaped gustatory sensory cells. Once dissolved chemicals from the bitten object attach themselves to the gustatory cells a signal passes to the brain which is instrumental in determining whether the shark rejects the meal or not. The taste organs are not as highly adapted as other shark senses as they do not play a role in locating prey. Many surfers mistaken for seals are thankful for the powers of a shark’s sense of taste.

Electroreception: Now the true superpower. At some point during the evolution of sharks, the lateral line pores around the snout developed a sensitivity to fluctuations of the electrical fields in the sharks’ habitat. These modified sensory organs consist of relatively large bulbous pores filled with a gelatinous substance. Connected to the pores are cylindrical canals in which the gelatinous secretions are stored. At the base of each pore is a sensory nerve which transports the electrical signals (which are collected by sensory cells lining the pore) to the brain. Actively hunting sharks may have as many as 1500 ampullae around their snout and head whilst more sedate species may only have a few hundred. The ampullae also react to a lesser degree to temperature and pressure changes.

The ability of sharks and rays to detect weak electrical signals in their surroundings may be one of the greatest factors relating to their survival through the millennia. The organs are sensitive enough for hammerheads and some other sharks to detect the small electrical signals put out by their prey whilst it hides motionless below the sand. In fact the ampullae are so sensitive that they can pick up voltage fluctuations of just 10 millionths of a volt or the equivalent of the electrical gradient of a AA battery with wires put into the sea 1 mile apart. It has been suggested that the widened heads of the hammerhead family may be an adaptation designed to increase the triangulation capabilities of their electroreception.

When sharks are close to prey it appears that their electrical sense takes over from sight or smell. This would explain why sharks which have been chummed to a fishing or shark diving boat will sometimes attack the propellers and other metal objects rather than the bait which has been put in the water in front of them.

For those with a strong stomach….

This video produced by Save Our Seas brilliantly encapsulates the problems of unregulated shark finning.

 

Save Our Sharks from Save Our Seas Foundation

Global status and conservation of oceanic pelagic sharks and rays

An interesting paper on the overexploitation of pelagic sharks and rays, exacerbated by the high demand for shark fins.

Here is the best paragraph from the paper:

Sharks are among the top predators in ocean ecosystems and continued depletion of their populations through overfishing could also have cascading effects for high seas biodiversity. ECOSIM models of the Venezuelan shelf, the Alaska Gyre and the French Frigate shoals in Hawaii suggest the removal of sharks results in changes in the abundance of some prey species. Similarly, the proliferation of cownose rays in coastal North-west Atlantic waters may stem primarily from over-exploitation of the great sharks. However, ECOSIM models of the open-ocean Central North Pacific ecosystem, which is more relevant to this study, suggest oceanic pelagic sharks do not have a keystone role because of their relatively low consumption rates, low production-to-biomass ratios and a wide range of prey types consumed compared with tuna and billfish. While the over-exploitation of sharks and rays may have minor ecosystem effects in oceanic pelagic systems, the intrinsic biodiversity value and long evolutionary history of these species provides strong argument for appropriate management and conservation.

Full link to the paper: http://www.lenfestocean.org/publications/Pelagic_Sharks_paper_final_version.pdf