Outdoors

OUTDOORS

UM marine school experiments with raising dolphin fish (mahi mahi)

 

scocking@miamiherald.com

They grow fast, have lots of offspring, and die young. Most people like to eat them and there’s more commercial effort to harvest them than ever before. The aquaculture program at University of Miami’s Rosenstiel School is growing them in tanks and aims to teach other fish farmers how to do it.

Dolphin fish, also known as mahi mahi, is the latest experimental research species at UM’s aquaculture lab on Virginia Key. The colorful pelagics join cobia, blackfin tuna, Florida pompano and goggle eyes swimming around in large fiberglass tanks.

“They are iconic yet elusive,” professor Dan Benetti, director of the university’s aquaculture program, said of dolphin. “There’s got to be somebody interested in raising these fish commercially.”

Growing dolphin in captivity is nothing new; scientists, including Benetti, have been at it on and off for about 30 years. Unlike some tuna and grouper-snapper species, mahis are not currently overfished, so there has been no urgent push to develop techniques to farm them. But that could change with increased consumer demand and fishing pressure. So last year, Benetti decided to “revisit” the species, looking for ways to raise them profitably and sustainably.

Getting the marine lab rats to reproduce has not been a problem. Beginning with a bull and several cows caught last fall off Miami by research assistants John Stieglitz and Ron Hoenig, the dolphin quickly spawned and their offspring have done the same. Now a couple thousand fish — from tiny larvae to the apex 20-pound bull nicknamed Guppy — occupy several tanks.

“They are the most prolific fish in the ocean,” Benetti said. “In five to six months, they’re already spawning. They spawn every day.”

But the downside to life in the fast lane is that they die young, he said — most before the age of 2 years.

The biggest challenge to raising dolphin has been to satisfy their enormous appetites, which unfortunately drives them to cannibalize one another.

Younger fish are fed pellets containing meal and oil made from other fish. As they grow larger, they get hunks of sardine and squid. But when they get hungry between feedings, even the fingerlings have been observed ganging up on their weaker brethren and devouring them like pack animals.

“They beat the cobia in nastiness,” Benetti said.

The scientists are looking for ways to replace fish meal and oil with a more economical and sustainable feed for their charges. Developing that technology would make dolphin more attractive to prospective farmers.

Meanwhile, Benetti’s 25 students and research assistants — many of them recreational anglers — seem enthusiastic about the dolphin project.

“They’re fun to work with,” Stieglitz said. “We’ve been doing cobia for so long, it’s a nice change of pace. And we enjoy the brood stock captures.”

Read more Outdoors stories from the Miami Herald

  • Outdoors notebook

    Southeast Florida anglers have less than one week to catch a snook for dinner before the annual spawning closure that begins Saturday and ends Sept. 1. The harvest season in Gulf waters, including the Keys and Everglades National Park, has been closed since the deep freeze in 2010. Florida Fish and Wildlife Conservation Commissioners will decide at their June meeting in Lakeland whether to reopen the Gulf to snook harvest on Sept. 1. Also closing Saturday are the recreational and commercial harvest seasons for greater amberjack in Gulf state and federal waters. Both seasons will reopen Aug. 1.

  • South Florida Boat Show

    South Florida Boat Show returns after short hiatus

    After the sprawling, glitzy Miami and Palm Beach international boat shows in February and March comes the smaller, revived South Florida Boat Show from Friday to June 2 at the Miami Beach Convention Center.

  •  

Volunteer war vets cross a canal in Homestead to reach the Frog Pond, a tract of undeveloped, state-owned land where they hunted for Burmese pythons.  The group found a few snakes, but none of the target species.

    Swamp Apes group gives war veterans missions in the Everglades

    When 30-year-old Iraq war veteran Jorge Martinez left the Marine Corps, he suffered from post-traumatic stress disorder. The vet wanted to readjust to civilian life and get involved in social activities, but being amid large crowds made him uncomfortable.

Get your Miami Heat Fan Gear!

Join the
Discussion

The Miami Herald is pleased to provide this opportunity to share information, experiences and observations about what's in the news. Some of the comments may be reprinted elsewhere on the site or in the newspaper. We encourage lively, open debate on the issues of the day, and ask that you refrain from profanity, hate speech, personal comments and remarks that are off point. Thank you for taking the time to offer your thoughts.

The Miami Herald uses Facebook's commenting system. You need to log in with a Facebook account in order to comment. If you have questions about commenting with your Facebook account, click here.

Have a news tip? You can send it anonymously. Click here to send us your tip - or - consider joining the Public Insight Network and become a source for The Miami Herald and el Nuevo Herald.

Hide Comments

This affects comments on all stories.

Cancel OK

  • Videos

  • Quick Job Search

Enter Keyword(s) Enter City Select a State Select a Category