Anna and I had just turned our dive and were moving back up the slope on the way to the dock of Tawali Resort on Papua New Guinea’s Milne Bay when we spotted a pair of signal gobies making a dreadful mess in the shallows. In all likelihood, we would have passed the little burrow builders right by if it hadn’t been for the conspicuous silt cloud rising above their labors. Delighted by our exciting find, we settled in for an extended stay.
Signal gobies (aka crab-eye gobies) are about as cute as fish can get. The two-inch fish bounce around on enlarged ventral and anal fins in a manner that mimics the light-hearted footwork of the Looney Tunes character Pepe Le Pew. We watched as each goby took a turn at burrow maintenance, sending forth a flume of silt with a madly thrashing tail. From time to time the hardworking partners took a break to scoop up mouthfuls of sediment and filter it for food. It was during one such interlude that we took notice of a bit of playful nipping and nuzzling going on. Just as the affectionate overtures began to mount, low tank pressures and a setting sun forced us back to the lodge, where the entertaining antics of Anna’s goofy little gobies dominated the dinner conversation.
The next morning Anna led a party of three divers back to the burrow to show off her love fish, but to her dismay one of the gobies was gone. She repeated her search each morning for the next two days without success. On day three, a friend reported seeing the pair together again. The news sent Anna back to the burrow, where, to her immense relief, she found the pair happily hopping about like puppets on strings.
A Google search uncovered a single paper on the natural history of Signigobius biocellatus; however, the lone document was sufficient to explain the absence of the missing mate. It seems that at maturity, signal gobies form monogamous pairs that build multiple burrows within a sandy home range about the size of a ping-pong table. Courtship entails the excavation of a honeymoon suite, coupled with a series of pecks and nudges. If a male’s charm offensive works its magic, the female deposits a cache of eggs inside the burrow. When the male enters to fertilize the eggs, the female seals him inside where he remains cloistered for a day or two tending their progeny.
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© Alert Diver — Q1 Winter 2010