Big fish disappearing from the ocean

We're eating most of the big fish from the ocean and replacing them with sardines. So says a new study:

"predators like tuna, cod and swordfish have seen their numbers drop by two-thirds over the past century, while small prey fish such as herring, caplin and anchovies have doubled."

This produces a "while the cat's away, the mice will play" scenario, where the nasty, hungry big tuna and swordfish have mostly been caught, and so little fish like sardines get to play in a much more hospitable ocean

This study says "yes" in the scientific debate over whether or not people have been fishing down food webs in the ocean--catching the big fish first and producing an ocean full of small fish. There is a "no" side to this debate, with strong evidence against the idea that we're everywhere fishing down food webs.

What's a fish lover to do? It's simple really, let's let the scientists duke it out over who's right and see who's left standing. The real challenge is getting people to behave better and not catch too many of the big fish or the little fish.

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When the world's biggest fish poops

Biologists are strange, and that really shows up when they start thinking and talking about poop. Witness biologist Alistair Dove talking about the lure of dipping a net to sample the poop of a whale shark, the world's biggest fish:

“Nobody has done this analysis yet,” said Dove, who referenced a scene from Jurassic Park, when Laura Dern’s character is ecstatic at the chance to poke through a pile of dinosaur droppings. “It could be a literal gold mine.”

Why is he so excited about a very large poop? Because it's a chance to learn a lot about a very interesting fish. It's hard to know what goes on inside a wild animal, and poop is one of the best ways to find out (without harming the animal, of course). According to Wired Science:

With a fresh sample, researchers could perform high-powered chemical and genetic analyses of its contents, learning in precise detail what these threatened giants consume in the wild. Dove is especially curious about their digestion. In aquariums they thrive on a relatively spartan diet, suggesting high efficiency in converting food. But a colleague on the research trip had observed whale shark defecation first-hand, and said their food was barely digested.

“He says it comes out looking much the same as when it goes in,” said Dove. “Maybe they’re efficient when food is scarce, but when they find a good patch, their efficiency drops in favor of gluttony. They’re eating so much, they just push it through.”

That colleague happened to find a group of whale sharks feeding — a spectacular affair, in which scores swim in a synchronized frenzy, sucking up water and food, and discharging wastes on the spot.

“Pooping events may play important oceanographic roles,” concentrating surface nutrients and delivering them to the water column and seafloor, said Dove. Scientists now think that baleen whales perform just such a task, and may be vital to nutrient circulation in the ocean.

Dove estimated the main plume in the photograph to be 30 feet long and 20 feet wide, and the smaller about 8 feet by 10 feet. If it’s three feet thick, the nutrient slurry would have a volume of 2,000 cubic feet. “Imagine you’ve got a big aggregation, dozens or hundreds of whale sharks, doing this all at the same time. That’s a lot of nutrients,” he said. Dove hopes to collect samples from just such a group.

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Where have the big fish gone?

Fishermen like to take pictures and show off their catch. Can that be turned into science? Yes, and the results are shocking. Where have all the big fish gone?

A study of fishing dock pictures from Key West shows a dramatic change in the last 50 years, the big fish are gone, G-O-N-E. No more big ones on the docks at Key West. In an interview, biologist Loren McClenachan talks about this research and what it all means.

Have we learned our lesson? I hope so. One reason the big fish are missing now is that fishery regulations protect some species like goliath grouper, and that's a good sign. Also, the protected areas near Key West are helping fish recover and helping me stay optimistic.

But I begin to wonder if we'll solve these problems when I see attempts to weaken federal law that requires sustainable fishing and other attempts to allow fishing to exceed scientific limits such as New England's war on science.

But then I get optimistic again when I see the people who buy fish taking a stand for responsible management and truly wise use of fish, including Gorton's in New England and Wal-Mart.

Regardless of our response to the loss of big fish, this story of loss is as American as John Prine. This song can tell you what happened (see YouTube video at the bottom of the post).


Key West 1957


Key West 1958


Key West 1965-79


Key West 1965-79


Key West 1980-85


Key West 1980-85

Key West 2007


Paradise John Prine

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$100,000 tuna

That's a pile of money for a fish, no wonder bluefin tuna are vanishing.

At the first auction of the year in Tokyo, two restaurant owners shared the prize tuna at a cost of $100,000 for the 280 pound fish. And that's not even the all-time record, in 2001 a 450 pound bluefin sold for $219,000 which is nearly $500 per pound. That's an expensive fish.

The writeup in the Wall Street Journal failed to mention the sad fact that these fantastic prices are driving bluefin tuna close to extinction. I guess they're too busy worrying about vanishing investment banks.

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Mysterious fish said to eat people in India

It's called a goonch, and it's a catfish that can get really big and is said to be eating people in India and Nepal.

The story is strange. The goonch probably started down the path of eating people by scavenging bodies disposed in rivers in the area, a common practice apparently. Now, some mysterious cases of disappearing people are attributed to a goonch pulling them underwater and eating them.

This is no run-of-the-mill catfish, they're BIG. They can get to be 200 pounds and they are certainly capable of pulling a person underwater. In one case of a disappearing Nepali boy, he was said to be pulled underwater by "an elongated pig." I suppose a goonch could be described as an elongated pig (see photo above).

The goonch that ate people, sounds like a Dr. Seuss book.

Hat tip: zooillogix

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Is this how bluefin tuna go extinct?

Celebrated with a glittering party, the world gathered to say goodbye to the bluefin tuna. At least, that's what happened in Barry Foy's satirical piece on feasting the beast to extinction.

It is possible for us to eat ocean creatures into oblivion. We just said goodbye to the Caribbean monk seal, declared extinct this week after we ate them into near-oblivion over a century ago.

Or will we actually reverse the trend and see bluefin tuna recover in our lifetimes? The choice is up to us.

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Up close and personal with giant fish

Face to face with fish bigger than me, maybe 20 of them. Wow. I was swimming along in water about 20 feet deep, and there they were, all around me. Double wow. Not every one bigger than me, but all of them 4-6 feet long, maybe more. Shiny silver tarpon, milling around. They let me come almost within touching distance, then slipped slowly away.

I hung around with them for 5 or 10 minutes as they slowy moved into deeper water and spread out. It was an amazing sight, and a little intimidating.

What else? Just a nurse shark, a goliath grouper (I think) a big jack of some kind, and lots of smaller fish. In warm water, it's a trip to make a Seattle guy happy.

Seems like the fish were bigger than the last two times I was here, more than 5 years ago. Hmmm...I wonder why?

Where was this great trip? I'll award a free lifetime subscription to blogfish to the first correct answer. And another free lifetime subscription to anyone who can name the ocean conservation luminaries I was with, pictured below.

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Fishing for a pot of gold

Fishing and fishermen can be strange, and bluefin tuna fishing is the strangest. Dedicated bluefin anglers will fish day after day, sometimes a whole season, with no success. They'll even curse other fish that get in the way, inlcuding fish that would make others cheer.

How did bluefin tuna fishing get so strange? Landing a bluefin tuna is like catching a pot of gold--an average bluefin will net $2,500 or more for the lucky angler who catches it and sells it into the Asian seafood market. Recently a bluefin tuna sold for more than %50,000 at the fish auction in Tokyo.

Bluefin fishing is getting tougher as the fish disappear. Not only that, but bluefin seem to be getting skinnier, weakened by unknown causes. Managers have been slow to respond to decades of overfishing of bluefin.

It's a shame to see bluefin tuna, this magnificent "cruise missle of the sea," in such a state.

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Huge oarfish, you won't believe this picture

Ever heard of an oarfish? It's huge, ornate, and magnificent, and very strange looking. Here is an incredible story of an oarfish beaching itself and being collected (after failed rescue attempts).

Oarfish are reputed to be the longest bony fish in the sea at well over 30 feet. They're rare, perhaps found mostly in deep water, but very occasionally seen on shore or in shallow water. They are ribbon shaped and swim by undulating their dorsal fins. This individual beached itself in Mexico, accompanied by another oarfish that eventually swam away.

Note to Jason at cephalopodcast.com, Gorton's law was invoked in the second response to the posting of this story, in record time for such a magnificent animal.

Hat tip: Brand Mongeau

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Skinny bluefin tuna

It's good to be fat, at least in the fish world. So nobody's cheering about the skinny bluefin tuna in Maine.

Creative science found skinny bluefin tuna by relying on the meticulous work of tuna grader Robert Campbell. Since bluefin can fetch a scary price when prime, upwards of $50 per pound, much attention is giving to separating the prime from the not-quite-prime.

Fortunately for fishery science, what makes bluefin tuna good to eat also makes them good for making baby tuna. It's all about the fat content, like pretty much any good desert and most good food. Is it fatty? Then it's good.

There is no obvious reason for skinny bluefin tuna, there seems to be plenty of herring to eat. Maybe it's the influence of mainstream media and unhealthy body images.

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Save the lobsters that lay the golden eggs

Throw back the big ones. It's a new principle in managing commercial fishing, designed to save the lobsters (or fish) that lay the golden eggs.

Finally, some of the old, broken ideas are giving way. It used to be thought that a simple mathematical construct (maximum sustainable yield) was actually a good way to manage fishing. Only there were too many neglected factors that fell outside of the model and undermined it's utility. Things like the special reproductive value of big old fish (and lobsters) and the value of life history diversity in maximizing productivity.

Fishermen will now be required to throw back the biggest lobsters, following the lead of Maine. It's an overdue step and one that promises to help protect the future of lobsters and lobstering.

Maybe we'll see more efforts made to save the fish (and lobsters) that lay the golden eggs. Some fish (and lobsters) are too valuable to kill, they're worth more in the water than in the fish market.

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Giant rockfish caught off Alaska

Here's a fish that was too valuable to kill: a century old "Teddy Roosevelt" rockfish--born when the roughrider was President.

The 44 inch, 60 pound giant shortraker rockfish was what's known as a "BOFFF," a Big Old Fat Female Fish with specieal breeding value. It was stuffed full of developing embryos in it's ovaries, just about ready to give birth to many thousands of live baby fish. It was worth more in the water than anywhere else.

Caught as "bycatch" (not what they were fishing for) by a commerical fishing boat, at least the fishermen recognized the value of the fish and delivered it to scientists instead of throwing it overboard (it was probably dead since it was hauled up from deep water).

Fishery science is only just beginning to recognize the value of BOFFFs. Or rather, scientists already know and it's fishery managers who don't acknowledge the value of BOFFFs. In fact, nutty as it sounds, getting rid of especially valuable breeders like this Teddy Roosevelt rockfish is part of fishery managers' grand plan for fish. It's all part of "The Good Depletion," an idea that is as obsolete as a buggy whip.

It's time for a paradigm shift in fishery management, one that makes use of modern ecological knowledge like the value of BOFFFs. Unfortunately, the die-hard proponents of The Good Depletion seem to want to go down swinging. Check out Ray Hilborn's unscientific diatribe against fisheries iconoclasts who dare to challenge The Good Depletion.

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White marlin an endangered species?

The plight of white marlin will test the mettle of fishing conservationists on the US East coast. A potential ESA listing may restrict fishing to save the fish.

What's a fisherman to do? The decline of white marlin is not in dispute, and the need for stringent action is obvious. Some credible fishing conservationists argue against listing, even though white marlin need help. ESA may not be the best tool to help these fish.

But what's the alternative? Will anyone take the plight of white marlin seriously if they're not listed?

The experience of salmon advocates can be informative. Listing of salmon as endangered does disrupt fishing, no question about that. But it seems to be the only thing that gets serious conservation action moving.

All of us fishing conservationists need to decide where we come down...on the side of the fish or on the side of our fishing? What is more important?

image: pointrunner

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Are big fish disappearing or not?

Depends on what you mean by "disappearing." Would you say that tuna are disappearing if only about 1 out of 3 are left?

A new study reports the mainstream view from fisheries scientists. They say that 64% of yellowfin tuna are gone, but that's not a problem. In fact, removal of 64% is the goal.

The study's authors say that fisheries management is working and yellowfin tuna are being managed appropriately and sustainably. They also note that previous studies reporting problems were "half-baked" and based on "cherry-picked" data, and that these issues "cannot be reduced to sound bites." Hmmm...I have no doubt that the study is good, even if their metaphors are badly mixed and their criticism is self-referential.

How do the two studies really differ? The new study shows that the biggest tuna have declined by 80%. This is actually quite similar to the 90% decline of large fish found previously. Both studies agree that the largest fish are at least 80% gone. That's a striking similarity. In the new study, the sharp criticism of previous results is based on relatively modest declines of a few smaller species such as skipjack tuna.

Interesting, the methods are different, but the findings are fairly similar when comparing big fish to big fish. By far the largest difference is the threshold for concern. So decide for yourself...is it ok to take most of the big fish out of the ocean?

The real conflict here is over the goals of fishery management. At stake is the future of our oceans and fish.

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The Good Depletion

Fish depletion is not a problem, it's the goal of fishery management. So says Ray Hilborn in "Re-interpreting the Fisheries crisis." So don't worry about disappearing fish, it's part of the grand management plan.

Thus we have The Good Depletion; it allows us to maximize our fish catches. Or so say the equations. The Good Depletion has us liquidating the big fish, shrinking population size by 60-80%, and thus increasing the "productivity" of exploited fish populations. Mr. Hilborn says the decline shown in the figure is not a problem, because we're still catching plenty of fish.

The Good Depletion was an advance in the mid 1900's, and it has some practical value. But it's time to give it a gold watch, a rocking chair, and a graceful retirement. Unfortunately, Mr. Hilborn and others want to keep it working in it's dotage.

We need a new paradigm for 21st century fisheries, and here's what I think it needs. It should maximize the probability of good reproduction years by valuing big fish (because of high reproductive value) and life history diversity (e.g. wide range of spawning times and places). It should maintain fish populations' geographic and age distribution. In brief, it should emphasize the value of what's in the ocean, not what comes out. Fishing should "make hay when the sun shines" by fishing hard during fish population booms, and switching to other species during lean times when reproduction is weak. To me this would be good ecosystem-based fishery management.

This whole fight reminds me of the transition in managing public old-growth forests of the Pacific northwest. When I came of age, we were clearcutting old-growth forests to produce maximum sustained yield, following the rationale of The Good Depletion (forestry version). It failed for many reasons, such as the forests that didn't regrow well in hot southern Oregon, or the wildlife that went missing in massive tree farms.

Science has undermined the assumptions of The Good Depletion (fisheries version). Equilibrium doesn't exist, all spawners are not equal, life history diversity is important, the ecosystem context matters, etc., etc.

Interestingly, Mr. Hilborn says this within the family, just not in public when The Good Depletion is threatened by outsiders. According to Mr. Hilborn and colleagues: "For some years the concept of maximum sustained yield (MSY) guided efforts at fisheries management. There is now widespread agreement that this concept was unfortunate," and "Distrust claims of sustainability. Because past resource exploitation has seldom been sustainable, any new plan that involves claims of sustainability should be suspect."

Circling the wagons around The Good Depletion won't save it. I suppose the testiness of its defenders (watch the video link) is evidence of the coming paradigm shift. Fishery scientists would do well to help fisheries make the transition, rather than propping up The Good Depletion until it's really too late and everything falls with a great crash.

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Bluefin tuna overfishing

Japan has been busted for serious overfishing of bluefin tuna. These magnificent oceanic "cruise missles" are among the most valuable seafood on earth. Without effective protection we might see the last one sold in our lifetimes, for some fantastic price.

In this context, the Japanese overfishing is a serious offense.

The Australian government was responsponsible for the bust, and they claim 20 years of Japanese poaching worth up to $8 billion, and illegal catch levels that prevented bluefin from rebuilding.

The Japanese government admits only modest and short term overfishing of bluefin tuna. However, they accepted stringent penalties that will cut Japanese bluefin quotas in half for 5 years.

It's a shame that some fishermen would so wantonly slaugher such a magnificent creature as bluefin tuna, in defiance of international management and conservation agreements. Bluefin are warm-blooded fish that can grow over 1500 pounds and swim nearly 50 miles per hour. The ocean version of a lion that runs like a cheetah.

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Good news for goliath grouper?

Goliath grouper are making a comeback in parts of Florida, and that's reason to cheer. These magnificent fish are now coming off the "species of concern" (=intensive care) list.

Goliath grouper (formerly known as jewfish) can get very LARGE (more than 800 pounds--much bigger than your refrigerator!) and they're popular since they can be easily seen or caught in shallow waters. (web video of a battle with a goliath-ya gotta see this, worth the long load time)

It took a fishing ban to start these fish on the road to recovery, and pressure is already mounting to end the ban. Fishing for goliath grouper now is like resuming a boxing match after a knocked-down boxer has barely struggled up off the floor. Will these fish be allowed to recover?

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