Heading across the channel from Catalina. Another 5 days gone. A chunk of work accomplished. We are seeing the end of the time looming. We can also see the body of work that is taking shape.
A few days ago, we did a lot of cage work. I’ll tell you about it later. But today, I want to start with this really cool observation, because it takes me somewhere worth considering.
While we were working during the day, placing cages and stocking them, etc., we noticed some REALLY big and REALLY curious sheepshead. These fish don’t get so big outside the preserve. They are caught by humans before they can grow that big. Here, though, there are some massive fish, with really big white grindey teeth. Just the right size to poke through the 1/8 inch mesh of our second cage design. These could very well be our Monster from Iron Bound Bay. We intended to replenish the cage to 5 sea hares, but I figured we had a “learnable moment”, so I offered one of the sea hares up to the biggest sheephead. SLURP, in it went. SPIT, out it flew. Then the teeth came out, BITE, out comes the ink. SHAKE, SLURP, and the sheephead swims away, John chasing and filming. The big fish spit and slurped a few more times, and then slurped for good. Goodbye mr sea hare. Thanks for teaching us something. Sorry you had to die.
Check out this movie:All this was pretty humbling to my lobster-centric view of things. Here was a very mobile sharp-eyed sight predator, whose presence would seem to be anathema to sea-hare survival. It raises the awkward question of the relative impact of sheephead vs lobsters on not only sea-hare abundance, but the community in general.
Actually, this kind of realization is what most community ecologists confront from time to time. Most ecologists tend to work with “what’s there”, that is the beasts you think are the players in a system. But there is always a chance that you are looking in the wrong place. That the REAL driver of the system is something else, a bacterium you don’t have the tools to study, an extinct species, or an over-fished species.
This doesn’t mean your conclusions are not correct, but it does threaten them with irrelevance.
Here, we were, building that case that the shallow rocky near-shore environment, in the absence of human fishing pressure, develops a large, hungry horde of lobsters, which eats every animal in its path, including sea hares, but also species more destructive to the kelp forest, such as sea urchins.
Then, we watch this big ole sheephead chase after the released lobster (to no avail), and then eat our sea hare like a red-hot candy, and wonder, oops, there’s what we should be studying. This guy will eat everything. I bet he’d eat an urchin without batting an eye.
An old friend of mine (graduate student at Moss Landing Marine Labs and Scripps Institution of Oceanography), Bob Cowen, studied these beasts out a San Nicolas Island back in the 80’s. I didn’t really pay attention to his work, but remember him talking about the destructive powers of these big male sheephead. Now I see his point.
This all brings up a very important point from a management perspective. The California Department of Fish and Game has historically set size and bag limits according to a sort of “farmers” mind set. Let the fishermen take the biggest animals, but keep the breeders in good condition and everything will work out fine. In the case of sheephead, there’s a little biology that makes this algorithm work out well for the DFG. These fish change sex: they start life as a female, and when they are the biggest female “in the block”, they change to male and compete with other males for the females. Since there will always be enough males around to inseminate the females, we can set a pretty small size limit that won’t harm the breeding females, only the large males.
This is the population-level perspective. However, Paul Dayton, Jeremy Jackson, and a host of other smart naturalists decry this perspective. They want an ecosystem-level perspective. What counts to them is not the breeding potential of the fished species, but its ECOLOGICAL potential. In the case of sheephead, the species is not threatened. It has a passable yearly recruitment. It adjusts its age of sex change to conditions on the ground. Everything is OK, from a farming, or fisheries mindset. But these experienced, thoughtful, community ecologists say FOUL. You are robbing the sheephead of its natural ecological function. Even a low density of these big bad males, will keep all the primary consumers (e.g., urchins) at bay, eating the abundant ones long before they damage the kelp beds. So, with the fisheries approach, the population may be doing fine, but its EFFECTS on the community are a joke. They can’t shape the community as they have for millennia because they can’t grow big.
Same goes for lobsters. A big (say greater than 5 pounds) lobster is an entirely different beast than his sub-legal 1-lb son. The natural (pre-fishery) community has droves of these big guys (you can see that in the catches of the early part of the 20th century). These lobsters very likely ate everything.
Of course this is all a great big hypothesis, but it is pretty well supported.
So what do we do, Mr. Science? Well, I’m just a cranky ole blogger with some new data, but here’s what I think anyway.
The fisheries people can start by considering these animals (lobsters and sheephead), not as sea-going pigs, which have a “maximum sustainable yield,” but rather as shapers of the ecological community. You need these big guys around, regardless of gender, because they shape your community, making it much more like the pre-human one.
Jeez, Capn Bilge. Aren’t you asking a lot of Joe Fisherman, who just wants his right to catch a fish, or bring up a delectable lobster?
Yes. But this HAS been done before. There is a doable pathway to this place. It starts with something called “slot limits.” This means you take only a particular size RANGE: nothing smaller than 3 ¼” carapace for lobster, but at the same time, nothing LARGER than say 5” carapace. There is already a little discussion about slot limits on spiny lobsters. Conspicuously absent from that discussion is the role of large lobsters as community shapers. Instead, most of the discussion regards a different consequence of large females; they produce orders of magnitude more eggs.
Both effects, together, make the argument overwhelming: 10-100 times more eggs released per square kilometer, and better control of urchin outbreaks. Slot limits rock. Let’s do it!
Too complex, you say. Can’t make the recreational fishing industry retool like that.
Yes we can. It has already been done. The trout fishery has TOTALLY done this. They have slot limits, and EVERYONE obeys them. Fishermen still CATCH the large individual, i.e., bigger than the slot. But then they take a picture and LET HIM GO! All over the Rockies the fishing people PRIDE themselves in this. There is almost a religion about preserving the big guys (maybe we should get Robert Redford to make a movie, “A reef runs through it” to give the lobster a human face). The river outfitters understand that it is these big bull trout, caught and released over and over again, that bring their business back to them, year after year.
By contrast, on Catalina, a lot of the poaching is by the people (not the majority, but a good chunk) who live at Catalina. You can see them out poaching every night. There is a titillating game of warden go seek. This is crazy. The locals should be the caretakers of the big bulls, not their assassins!
Ok. Here’s how we do this. “Give” the people of Catalina the Isthmus Reef. Nobody is allowed to fish for sheephead OR lobster on Isthmus Reef without a local Catalina resident on board. Pay for the resident warden to go to fishery school for a year, and pay them through fishing fees. Then let them oversee the protection of the “Big Bulls” on Isthmus Reef. Inform all the cattle boats with recreational fisherman, and get them on board. Put buoys around the reef with signs laying out the rule. No fishing without a guide. If you don’t have a guide you have to go somewhere else. Some macho fisherman from the mainland comes over, and tries to sneaks out with a big guy from the reef has a problem. Someone on the island, not necessarily even a deputized warden, catches this poacher, and he is in big trouble, and not just because of the fine. He gets a heartfelt tongue-lashing from someone who has grown to be proud of their reef full of “big bulls”.
Let the public fish the other spots without a guide, but give the responsibility of guarding Isthmus Reef to the residents. Pretty soon, something happens. People don’t want to catch a bunch of small lobsters and sheephead to take home. They want to catch a BIG beast. They pay extra money to fish or dive on Isthmus Reef, with a local guide. They bring home pictures. The word spreads. The reef has some MONSTERS. The island has employment. More and more Islanders get work as guides. But even more important the island has PRIDE. Pretty soon the present-day sub-culture of poaching changes to a energetic, even fanatical, culture of protection.
Please note that this is NOT a Marine Life Protected Area idea. That idea, as important as it is, does not integrate well with local culture. The idea of an outside authority imposing its will on the locals, many of whom have grown up in these waters, is proving itself to be too abrasive to fully function in cultural settings like Catalina. This idea is much more internal, and organic. Something like this has already been done on tropical pacific islands with the giant clam. I can’t remember the reference, but local communities pitch together to protect their cherished brood stock, close to their community, from would-be poachers. Seems totally parallel to the Catalina Island situation. Let’s do it guys. Come on Catalina! I bet you could make this work and REALLY put Two Harbors on the map.
Wow. The ferry just arrived. What a diatribe I’ve perpetrated. Sorry. Last time, I promise.
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