John McCosker

Ocean Alert

Recorded: December 9, 2013

John McCosker, PhD, the Chair of the Department of Aquatic Biology at the California Academy of Sciences shares his thoughts about the perils that our oceans face, and his concerns about the future of our oceans.

Also known as “Dr. Shark”, John McCosker, is the Chair of the Department of Aquatic Biology at the California Academy of Sciences in San Francisco, and has held that position since 1995.  He graduated from Occidental College in 1967 and received his Ph.D. from the Scripps Institution of Oceanography in 1973.  He was awarded a DSc from Occidental College in 1987.  He taught briefly at the University of California, San Diego, and was then hired to direct the Steinhart Aquarium from 1973-1995. He has also served as Interim Executive Director of the California Academy of Sciences, as needed.

McCosker has written more than 275 popular and technical papers and books and has appeared in numerous BBC, NOVA, and Discovery channel documentaries.

Trained as an evolutionary biologist, his research activities have subsequently broadened to include field and laboratory studies ranging from microscopic bioluminescent bacteria to macroscopic man-eating elasmobranchs.  He has also studied the biology of salmonid fishes, the biology of coelacanths, dispersed and renewable energy sources as alternatives to national vulnerability and war, and the public understanding of sustainable sea foods. He is well known for his aquatic studies all over the world, but especially in sensitive ecosystems such as the Galápagos. He has studied the marine biodiversity of the Galápagos using scuba and deepwater submersibles to 1000 meters in depth. His research on white shark behavior concerns their natural feeding behavior and unprovoked attacks on humans. His work has contributed to our understanding of white shark behavior and has helped to formulate public safety policies for coastal waters, as well as helping to create legislation to protect sharks. He recently provided the scientific advice necessary to pass legislation disallowing the sale of shark fins in California.

John McCosker:    Other than elevation of sea temperature, ocean acidification is probably the single most destructive factor in the world’s oceans, because invertebrates require a certain pH level in order for their calcium carbonate skeletons to form, and now they’re just melting away.  It’s suggested that within a human generation coral reefs will be gone and the effects on our coastlines, the effects on the oceans should those coral reefs disappear is hard to imagine, because coral reefs are of course, you know the forests of the sea.  It’s the majority of all of these creatures along the coastal zone and the tropics and subtropics require these forests in order to survive.  So it would be like clear cutting the forest of the world if we lose the coral reefs, and this is caused by climate change.  This is caused by the increase in carbon in the atmosphere.  Fish are disappearing.  The world’s fisheries have so overfished the oceans that it’s changed the ecosystems, and I predict that the future of the world’s oceans is in a word, jellyfish. It’s happening already.  Actually, we are going through essentially a spiral, a decent, where the atrophic cascade is going downwards in oceans now are chalk-a-block full of jellyfish consuming what larval fish would have eaten, consuming what larval fish remain.  Jellyfish are an enormous problem and that’s the default position of the world’s oceans.

John McCosker:    About 10% of the abundance of sharks since I was born, remains in the world’s oceans and they’re still being hunted.  Estimates of 70 to 100 million sharks a year are being killed just so that their fins can be cut off and made into shark fin soup.  My own research interest is the behavior of white sharks, some call them great white sharks, they don’t require a hyperbale.  They’re the largest flesh eating shark on the planet.  They’re responsible for a few fatalities worldwide every year, one or two attacks every year in California waters.  Far disproportionate to the public’s reaction.  But having said that, it gets people’s attention and once that I’ve got their attention, I tell them that the only good shark is a live shark, not a dead shark, because we so depend on the ecosystem services provided by sharks, and California particularly by white sharks.  White sharks are apex predators, that is they are very important in the control of ecosystems and that service that they provide by culling seals, sea lions and other fish eating creatures that are the next step on the food chain, is very important.

Huey Johnson: I’m very oriented toward policy and politics as relates to resources and worry that the oceans seem to lack a structure of governance and the U.N. could be that possibility but it isn’t.

John McCosker:    Many times people have tried to have some body oversee the world’s oceans.  The fact that we even have a 200-mile limit where we have exclusive economic control is good, but think of the rest of the world.  The oceans cover 2/3 of the planet and they aren’t governed except that 200-mile zone.  One can do most anything in the oceans without any retribution whatsoever.  So yes, there should be a U.N. type body.  The law of the sea has never been agreed to, it’s never been passed because there are so many mineral rights underwater, and other things going on underwater in terms of extractive opportunities that the large nations won’t allow it, and the small nations want their piece of the action as well, so there will be no agreement probably in our lifetimes, but there must be.  So if we paid enough attention to the oceans, I think that other nations would follow our lead.  I am hopeful.  I’m not optimistic about the future, but I’m hopeful because I think that the youth of this visiting nation that comes to our museum, have convinced me that they can convince their parents to behave differently.  I have seen kids tell their parents, “You can’t eat that fish.  It’s the wrong thing to eat.  Look at your seafood card, is it on the seafood card?”  They will tell their parents what they should be doing, so I am hopeful that children will save planet earth, because their parents and grandparents have made a mess of it, and I think that children are sophisticated enough now that they will try and save it.


  • Cathleen Mallett

    Very interesting comment about the increase of jelly fish. I have heard about the difficulties that coral are experiencing. I am wondering why Dr. John doesn’t appear more on Social Media. He has a wealth of experience and voice that should be put out in the forefront.