Misool reefs and fish

Note: the following post is the latest in a series chronicling the ongoing expedition to the Raja Ampat Islands. Read more here.

Misool. Perfect one day, even better the next. The weather is so calm we could be forgiven for thinking we’re diving in a lake! We’re on schedule, fitting in three dives per day, and our evenings on the boat are busy with everyone entering pages of fish and coral data into the computer.

We’re collecting data on the status of the reefs for two reasons. The first is to check on sites identified for extra protection. These sites will be declared as no-take zones in the future, and we want to make sure they’re in good condition.

The second is to compare the health of reefs in different types of zones within the MPA. In particular, we want to compare no-take zones with zones where certain human uses are allowed. Even in Misool — a highly biodiverse area where protective measures have been taken — populations of valuable species like grouper are declining. We hope no-take zones will create “fish banks” — places where fish can grow and reproduce. There is already one no-take zone which has been established for a few years in Misool, and more are planned.

Increases in the number and size of fish are good indicators that a no-take zone is working well. Increases in fish size result in exponentially higher levels of egg production. For example, if a fish that’s 20-cm-long produces 10,000 eggs, then a 40-cm-long fish can produce 100,000,000 eggs! Many of those eggs will drift outside the no-take zone to replenish areas where fishing is allowed. That’s good incentive for leaving the fish in the water to develop a little longer…

Napoleon Wrasse in Misool

We’re also looking for a return of some of the large iconic species, like grouper, bumphead parrotfish and napoleon wrasse (see above), which quickly disappear even with moderate levels of fishing. These large species all play different but critical roles in keeping a natural balance on the reefs. Groupers are top predators that keep populations of smaller fish in check, bumphead parrotfish are experts in keeping the reefs clean of algae, and napoleon wrasse eat the notorious crown-of-thorns starfish — a voracious coral eater.

Anchovy fish ball

But it’s not just the big fish that are important. Two days ago, we were thrilled to see a “fish ball” (see above) — a school of hundreds of thousands of anchovies whirling above us, trying to escape the many hungry predators lurking at the ball’s edges. These are some of the smallest fish on the reef but are, in many ways, also the most important. They are the main food not only for fish but for other animals in the ecosystem, including sea birds and dolphins. A school of anchovies this size means there’s a good foundation for a healthy productive ecosystem in Misool.

(First image: A reef in Misool. First image credit: TNC. Second image: A napoleon wrasse. Second image credit: TNC. Third image: An anchovy fish ball. Third image credit: TNC.)

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