Friday, May 25, 2007

The Clowns

We found these two little Anemonefish (Amphiprion chrysopterus) tucked into their anemone home just outside the entrance to the Blue Grotto at the North end of Saipan. These little guys have to be one of my favorite fishes. There is something about the way they move in synchrony, drifting back and forth between the tentacles. They are too cute.

Anemonefish like these live in close association with large sea anemones, each species having a preferred anemone species as its host. Large anemones often host a semipermanent monogamous pair of of adult aneomnefish as well as a cadre of juveniles. Aneomnefish are what is know as protandrous hermaphrodites, meaning that they are hatched as sexually immature fry and remain sexually immature, develop as males, or develop as females based on environmental cues. Groups of anemonefish are matriarchal with the largest individual in the group being the dominant female. If the female dies or is removed from the group, the most dominant male then changes into a female and the rest of the males move up in the hierarchy. Each change from juvenile to male and from male to female is irreversible.

Anemonefish usually spawn around the full moon but during the warmer months in warm temperate waters. Generally, hundreds of adhesive eggs are laid in a patch of cleared rock near the base of the anemone. They are cared for by the male and hatching generally occurs after about a week. The newly hatched larvae drift in the plankton for about sixteen days before settling and seeking a new anemone.


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