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Larval rearing of the mahi-mahi, Coryphaena hippurus

April 01, 2014

Family: Coryphaenidae > Genus: Coryphaena > Species: C. hippurus

 

Dolphinfishes are large, epipelagic, predatory fishes that primarily occur in tropical and sub-tropical seas worldwide. The family presently only comprises two species, the common dolphin or mahi-mahi (Coryphaena hippurus) and the pompano dolphin (C. equiselis). Dolphinfishes are among the fastest growing fishes in the ocean and serve as a primary food source for many pelagic predators. Juveniles and adults occur mostly near the surface where they often associate with floating debris, particularly Sargassum seaweed. The larvae are often found in deeper water up to 600 feet. Dolphinfishes are delicious to eat and are an important part of recreational and commercial fisheries. Their high demand, fast growth rate, good food conversion efficiency, high fecundity and short larval phase make them excellent candidates for aquaculture.

Mahi-mahi (Coryphaena hippurus) larvae were reared on multiple occasions in the winter-spring of 2012-1014 from wild collected eggs (1.3 mm in diameter).  The larvae have unpigmented eyes and an unformed mouth at hatching, yet are relatively large, at 3.5 mm TL. First feeding larvae (3 dph, 5 mm TL) prey on large copepod nauplii and copepodites (70-100 um) in the rearing tank. Development is rapid with larvae undergoing flexion as early as 10 dph (8 mm TL). Juvenile transformation is complete near 20 dph (20 mm TL).  The larvae are heavily pigmented (yellow-brown) at all stages, except for the caudal peduncle and its finfold in the early preflexion stage.

Mahi-mahi larvae are easy to raise (experienced 0% larval mortality in all trials) and require no special conditions through transformation. The larvae readily feed on copepods throughout the rearing phase, unlike other epipelagic species such as tuna larvae, that prey exclusively on larval fish during later stages. Later stage mahi-mahi will also feed on artemia but grow noticeable slower than when raised on a copepod-only diet. Juveniles start to accept frozen foods at about 25 mm TL and can even be hand fed. Like adult mahi-mahi, juveniles develop beautiful iridescent color patterns that change depending on their stress level. This is the fastest growing fish species cultured for the project to date.