Saturday, September 20, 2008

Love is in the Water

We're south of the equator here (8 degrees or so), which means that it's Spring, and you can certainly tell by the behavior of the critters hereabouts.

We did two dives today at a site called Castle Rock, where there is often a current running ("breezy" or "drafty" and sometimes "gusty," depending on who you listen to). Currents tend to bring in bigger life, and this site is no exception. As we dropped in, we could see numerous white tip reef sharks cruising by. There we lots of trevally jacks, mackerel, and some tuna, too. Some of the mackerel were getting a bit frisky, swimming side-by-side, bumping into each other, getting excited.

After watching that show for a while, we headed up the sea mount to shallower water. There were some really nice corals and lots of fish; pleasant to watch. I spotted a pair of camouflage groupers circling around one another. This was clearly a mating/courting ritual. We watched for a while, and then noticed a much bigger grouper come peeking around the rock, apparently deciding all was going well, and heading off again. I decided this must be the chaperon. After a couple more minutes a third grouper of the same sort, but showing rather different coloration, joined in. One of the others, presumably the female, moved off, and the two others literally faced off, sitting nose-to-nose for a couple of minutes. Then there was a little snapping, some displays of wide-open mouths, and the interloper (I think) moved on. The female returned, and the courting resumed.

One positive thing I noticed this morning was a crown-of-thorns starfish. These are known as a great, voracious pest in many places, and the last time I recall seeing any was on our honeymoon ten years ago in Fiji, where they had devastated quite a number of reefs, practically scraping them bare. We were told at the time that the rise of the crown-of-thorns correlated with the decline of giant clams, which filter enormous amounts of water, including filtering out the eggs of the crown-of-thorns.

Here we have noted quite a few clams, although not the truly huge ones, but they seem to be doing the job of keeping the crown-of-thorns in check. Balance is important.

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