Ornamental Saltwater Species Bred in Captivity to Conserve Reefs

AUSTIN, Texas, October 6, 2011 (ENS) – Marine biologists at the University of Texas at Austin’s Marine Science Institute are developing means to breed saltwater aquarium fish, seahorses, plankton and invertebrates in captivity to preserve coral reefs.

The scientists believe these efforts, and those of colleagues around the world, could shift much of the $1 billion marine ornamental industry toward entrepreneurs who are working sustainably to raise fish for the aquarium trade.

“It’s the kind of thing that could transform the industry in the way that the idea of ‘organic’ has changed the way people grow and buy fruits and vegetables,” says Joan Holt, professor and associate chair of marine science at the University of Texas at Austin.

The methods currently used to bring sea creatures from the oceans to aquarium tanks are “extraordinarily wasteful,” says Dr. Holt, the associate director of the Fisheries and Mariculture Lab at the University of Texas at Austin Marine Science Institute in Port Aransas.

The peppermint shrimp is one of seven marine ornamental species that Joan Holt has bred in captivity. In tanks, it consumes parasites and dead or diseased tissue from other animals. (Photo by Paul J. Thompson)

“One popular method is to use a cyanide solution,” says Holt. “It’s squirted into the holes and crevices of the reef and it anesthetizes the fish. They float to the surface. Then the collectors can just scoop them up, and the ones that wake up are shipped out.”

This method, says Holt, has a number of adverse effects. It bleaches the coral. It kills or harms other species living in the coral their home, particularly those that cannot swim away from the cyanide. It can deplete or distort the native populations of the species.

Holt says 80 percent of traded animals die before ever reaching a tank.

“We want enthusiasts to be able to stock their saltwater tanks with sustainably-raised, coral-safe species,” she said.

Holt is a co-author of a recent article, “Advances in Breeding and Rearing Marine Ornamentals,” published in the “Journal of the World Aquaculture Society” in April.

The paper is a complement to Holt’s work over the past 10 years to promote captive breeding of ornamental species. She is a pioneer in developing food sources and tank designs that enable fragile larvae to survive to adulthood.

Unlike the freshwater ornamental market, which relies mostly on fish raised in captivity, the saltwater ornamental market is 99.9 percent wild caught.

Holt says this is because less knowledge exists about breeding saltwater fish in captivity.

Saltwater species tend to spawn larvae that are smaller and less robust than freshwater species. Not only are saltwater species harder to rear to maturity, but they rely on foods, such as plankton, that are not readily available in mass quantities for breeders.

Yet all these difficulties are surmountable, says Holt.

She and her colleagues in Port Aransas, where the Marine Science Institute is located, have successfully bred in captivity seven species of fish, seahorses and shrimp they’ve caught from the Gulf of Mexico and the Caribbean, including species that other biologists had tried but failed to rear before.

Others have successfully bred popular species like clownfish, gobies, dottybacks, and dragonets, as well as coral, clams, invertebrates, and algae.

Several big aquaria, including SeaWorld, have committed to assisting in the breeding and egg collection effort, and to integrating into their exhibits information about how the aquarium trade impacts the coral reefs.

Holt and her colleagues envision a “coral-safe” movement with identifying labels, similar to the “dolphin-safe” tuna movement that resulted in fewer dolphins being incidentally caught in tuna nets.

The science, the economics and the social awareness could together result in a change in how saltwater aquariums are populated. As more tank-raised ornamental species reach the market, Holt believes the fish will do better, live longer, be healthier and easier to care for.

“Species that are bred in captivity should adapt much better to your tank than something that was just caught halfway across the world, in a different system,” says Holt. “Good retailers will want to sell these species, and consumers will benefit from buying them.”

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