Fish

We had another beach fire last night. Alisa took the boys in early and gave them a play on the beach and a long swim and a scrub in the salt water while I stayed on the boat to get in a few hours of work. I then swam to the beach, seeing the inevitable groupers/parrotfish/damsels/butterflyfish/goatfish/wrasse/rabbitfish on the way.

In Hobart and Kodiak Alisa and I got into swimming laps to stay fit, and I love swimming in the tropics when the exercise is punctuated by fish viewing. The apogee is seeing a species I've never seen before, a "lifer", when out for my afternoon exercise.

For years now we've been keeping track of the species we've seen in our guide to the coral reef fishes of the Pacific and on this trip Elias has gotten well into it, sitting down with me after a snorkeling session to check our pictures against the book. He led me into a very shallow channel between motus the other day, the water only a meter deep and pulsing with the current from water being swept in over the seaward side of the reef. In this new habitat we saw a new species of damselfish, the gray demoiselle (in spite of the uninspiring name, the juvenile is a sapphire gem) and a new sandperch, the spotted sandperch.

I look at the outer reef, where the coral meets the profound depths of the ocean, and think of all the new species that would be waiting to be seen there. The trick is that you have to make it over the surf on the reef edge, and then back, but it doesn't look too bad at this point on the reef. If only I had a buddy to go with who was a little more burly than Elias.

I could smell the fire when I was still swimming, the universal campfire/beachfire smell that is exactly the same in Alaska and the Tuamotus greeting me with each turn of the head and rhythmic breath. The boys were happily gathering wood when I waded ashore, and soon even more happily roasting marshmallows.

Alisa and I noted how the nine or ten boats in sight were all evenly spread around atoll, each anchored off their own little scrap of motu.

"Isn't that the ideal free distribution?" I asked Alisa, my grasp of ecological concepts proving shaky without the crutch of a reference.

We started talking about where the trend in numbers of traveling boats might be headed. Forty years ago you'd be quite certain to find no other voyaging boats in a place like Tahanea. Now we assume that there will always be other anchored boats in sight, but we also assume that there will be a motu available just for us, with its beach and coconuts and dead wood for burning. We live an age of dark assumptions about the future, so that the baseline assumption is that we're living in a bubble that allows so many people the luxury of their own capable ocean-crossing yachts, and these herds of boats in places like Tahanea will become a thing of the past during our boys' lifetimes. But there is also the empirical view that, whatever the ultimate limits to our resources, wealth has increased steadily over time (for most everyone in one of our countries, Australia, and for the haves in our other country, America) and is likely to continue to do so.

That's one of the reasons that I'd love for life to just go on and on. I'd like to see what happens next, see how everything in the story turns out.

We have information from a very trustworthy source that the groupers we're seeing, and the soldierfish, and a few others, are free of ciguatera, that bio-accumulated toxin that can make eating reef fish so dangerous.

Still, we're too conservative, with the boys aboard, to eat the reef fish. The downside of one of them getting sick is too great to risk the probably very slight, but plausible, chance - the ciguatera that suddenly appears in a species, or area, for the first time, for instance.

This is also a situation where being an ecologist colors your perception of the world. Much of my reading in ecology, and some of my own research, has to do with the fundamental way that predators - like those groupers - structure communities of living things. The character of any place that you can name on the planet is largely driven by the presence or absence of predators. If you put foxes on an island in the Aleutians, the grass disappears (and no, it's not because foxes eat grass). Birds live in chaparral until subdivisions fragment the habitat to the point where cat-eating coyotes can't make it. One of the great trends of our times is the loss of predators from ecosystems everywhere.

At times - back in Alaska, on passage in the tropics - we fish as hard as we can. But in a place like this, a spatially restricted example of an ecosystem type that is undergoing massive stress globally, with no fisheries management whatsoever, and eight or nine boats generally in view during the cyclone season, each of them potentially capable of removing a few slow-growing, long-lived fish, I'm happy to just leave the groupers under their ledges in the coral, looking up at me as I swim in to the beach where my family has built a fire.

(Meaning no criticism of our friends who do fish here!)