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Seahorse Nursery
Aquarist Norton Chan has had his hands full lately with all the newborns arriving at the Aquarium. First it was the bigfin squid. Now he's raising seahorses. In early August, one of the male seahorses in Gallery 3 began to look like he was in a fatherly way. The seahorse, which is one of the species found in local waters, was placed in a nursery tank behind the scenes, where he gave birth several days later to around 500 offspring - all perfectly formed seahorses about 4 millimeters high. And it's obviously the season: a second small herd was born in early September.
And while there is all this activity behind the scenes at the Aquarium, seahorses in the wild also appear to be enjoying something of a resurgence. It used to be that seeing a seahorse was a rare experience - now they are popping up everywhere.
"People have found them in ankle-deep water at Magic Island; they've been seen along the shoreline at Pearl Harbor and in Kaneohe Bay; and there are lots at piers and harbors like the Kaneohe Bay Yacht Club and the Ala Wai," Chan says.
This phenomenon, where a species has a sudden resurgence, often happens thanks to a fluke of good conditions. If a high number of juveniles survive in one breeding season, the population can quickly build on itself. The same thing has recently been witnessed in the bigfin squid.
The Aquarium has long worked on breeding and raising seahorses. Of course, one of the many fascinating things about these animals is their breeding habits. It starts with daily bonding activities as the seahorse couple swim together each morning with their tails entwined. When it's time to mate, the female deposits her eggs into a brood pouch on the male's belly, where they are fertilized. The father carries the developing embryos until they are fully formed. His labor can last up to a day and a half.
The young emerge as fully formed--and hungry--seahorses.
Because they have no teeth or true stomach, food passes through their digestive tract very quickly, making them voracious eaters. Chan started the new herd on copepods and newly hatched brine shrimp.
The knowledge gained while raising these seahorses can ultimately help protect these animals in the wild. Around the world, many species of seahorses are threatened by overfishing. They are in high demand for medicinal purposes in Asia and many more are sold as souvenirs. The endearing fish are also popular aquarium pets, and the recent population peak in Hawaii has resulted in an influx of wild-caught seahorses into the pet stores.
But Chan urges caution if you're tempted to keep a seahorse as a pet. Wild-caught seahorses prefer live food, which can be very difficult to obtain, so these animals often come to an unfortunate and quick end. Aquacultured or tank-raised juveniles that are accustomed to frozen foods can be hardier, he says.
SEAHORSE STATS
Name: Hippocampus kuda, smooth seahorse
Color: Ranges from yellow to orange to black
Length: Average 11 to 13 centimetres
Life Span: Can be more than 2 years in captivity
Diet: Crustacean plankton
Sexual maturity: Ranges from 4 to 12 months
Gestation: 9 to 10 days at warmer temperatures