In the first weeks, the fish are exposed to constant light to promote survival and growth. We have not administered antibiotics or vaccines to any of the fish raised as part of this program.

Newly hatched winter flounder larvae do not feed right away, instead drawing nutrition from the yolk sac they were born with. Within a few days they begin to eat rotifers—tiny marine animals raised by UNH researchers at the Coastal Marine Lab. At the same time, the tank water is enriched with microalgae. Not only does this algae make the rotifers a more nutritious food, but the algal particles provide a contrasting background which may make these translucent animals easier for the flounder to spot. As the fish grow larger and their mouth size increases, they are fed Artemia, or brine shrimp. Ultimately, the flounder larvae are weaned from live prey to a formulated commercial diet for coldwater marine finfish.

At about 3 weeks, the larvae begin to undergo metamorphosis—the process in which one eye migrates to the other side of the body so that both eyes are situated on the upward-facing side of the fish and the fish change from a pelagic (in the water column) lifestyle to a benthic (or bottom) lifestyle. When the process is complete, larvae have become juveniles. This is a particularly stressful time for the young fish, and a phase in which high mortality can occur. Our current research is investigating the gut development during this period and focusing on when is the best time to wean these fish onto commericial diets so that stress is minimized and these fish transition into healthy juveniles.