Coral reef goby has two month lifespan

If you find it amazing that some killifish can mature, breed and die in the space of a year, you ain't seen nothing yet.

Amazing new research published today in the journal Current Biology describes how a tiny coral reef goby has a maximum natural lifespan of less than two months.

Martial Depcyznski and David Bellwood of James Cook University's Centre for Coral Reef Biodiversity studied the gobiid fish Eviota sigillata and found that it's average generation time was a mere 49 days, with the maximum lifespan being just 59 days.

The study, which was undertaken on the Great Barrier reef, used the otoliths, or ear bones, of the tiny fishes to detect their ages.

Like fish scales and the rings of trees, otoliths contain a series of concentric rings called annuli which form a record of the fishes' growth, allowing it to be aged.

Every day sees a new ring on the otolith of the gobies, so by counting the tiny rings on their earbones with a special microscope, the scientists were able to work out, fairly accurately, how old the fish were.

The results showed that the larvae spent three weeks drifting around in the plankton before settling down on the reef. After a week or two, the young fish reach sexual maturity, and in the last three weeks of their lives, they breed. Starting the process off again.

Interestingly, the scientists also bred the fish in aquariums so they could monitor the growth of the fish through their larval phase and found that the fish didn't just breed once, as you might expect for a fish with so little time to play with.

Each female was able to produce up to three clutches of eggs within an 11-17 day window, giving it the potential to produce around 400 youngsters, if all goes well.

Not only is this life history strategy a record in the fish world, it's also the shortest known lifespan of any known vertebrate animal.

For more fascinating details see the paper: Depczynski, M and DR Bellwood (2005) - Shortest recorded vertebrate lifespan found in a coral reef fish. Current Biology, Vol. 15, No. 8.