Fishy Love

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Spawning butter hamlets. Photo by Ned DeLoach.

The first time we ever saw Hamlets spawn, Ned and I were on a liveaboard REEF trip in Belize. We were just starting serious work on the behavior book at the time and still unaware of just how rewarding dusk dives can be for fish watchers. Trying to squeeze in a fourth dive before dark, our group dropped in just before sunset, agreeing to be back up in time for dinner.

These were the days when I could still add new fish to my life list on almost every dive trip and the charismatic Hamlets with their 11 distinct color morphs and various “hybrid” variations were especially prized sightings (we’ll save the species debate for another day). Hamlets are solitary hunters during the day. So when we saw two chasing each other about, we instinctively knew something out of the ordinary was happening. But, was it love or war?

The traditional color of one of the pair was noticeably blanched. We’d seen that happen with fighting Sailfin blennies - the fish that was out of its hole turns very pale. But the behavior of the Hamlets was more reminiscent of flirtation rather than conflict. The fish being pursued would race ahead then stop, usually with its nose pointed up, twitch, and immediately take off once again as soon as the pursuer caught up. For over twenty minutes they dashed about in all directions before always returning to the same coral head.

Finally, just as the last light was fading, the hamlets paused above the coral head only inches apart, entwined their 3-inch bodies and slowly rose together a foot or two. I know we aren’t supposed to anthropomorphize, but it certainly looked like love to us. Suddenly, they popped apart releasing a white puff of gametes and immediately darted back toward the reef. Instead of going their separate ways, the chasing, nuzzling and twitching began anew and shortly they spawned again, then again and again before they finally disappeared, going their separate ways into the night.

Later we learned to our amazement that Hamlets are simultaneous hermaphrodites, with each partner possessing both male and female reproductive organs. This unusual scenario, known as egg trading, allows each couple to play both the male and female role each evening. The fish assuming the role of the female plays the aggressor, twitching and chasing the blanched, interim male about. After each spawn the roles reverse until the lovers are finally spent.

The best news for fishwatchers is Hamlets appear to spawn each evening year-round. So, on your next dusk dive in the Tropical Western Atlantic make a point of watching for Hamlets; if you do you’re sure to be entertained.

Note: a short video of Spawning Hamlets is available on REEF’s YouTube Channel, WeSpeakFish: http://www.youtube.com/watch?v=lEMCqVBB0CM

Design by Joanne Kidd, development by Ben Weintraub