Researchers in Hawaii with Hawaii’s Oceanic Institute and Rising Tide Conservation gained some important insight into their quest to successfully cultivate the yellow tang (Zebrasoma flavescens), one of the most popular fish in the saltwater aquarium trade. In their latest efforts to cultivate the fish post hatch (the number of days in which the fry survive), researcher Chad Callan of the Oceanic Institute and his colleagues were able to surpass the 40 day post hatch record held by Syd Kraul of Pacific Planktonics in 2004-05, effectively doubling the survival of a single specimen to 83 days.
What they learned from this particular hatch is that the yellow tang larvae are “inefficient feeders.” The larvae were fed newly hatched Artemia nauplii, which they note in their blog would make for easy prey items for the fish, but instead observed the fish strike and miss the target, and when they did catch one, many would spit them out.
They said on their blog that the brine shrimp do not seem an adequate food source for the yellow tang larvae at the early stages of their development, and enriched brine shrimp were also rejected by the brood, which numbered in the thousands after two to three weeks time, then down to 600 larvae at day 35. At day 50, 150 yellow tang larvae were still swimming in the tanks. Day 60 saw just 25 fish, and day 65, just three fish survived. Lucky was the last fish to finally die, at day 83.
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The Oceanic Institute has been attempting to successfully rear yellow tang since 2001. The fish is the most popular species collected from Hawaiian reefs, and last year, a limit of five fish per day larger than 2 inches was enacted in West Hawaii on the Big Island. Yellow tang larger than 4.5 inches are also limited to five fish per day. Support for the initiative came from Rising Tide Conservation and the Hawaii Tourism Authority.