Denson, M.R., Smith, T.I.J.
Abstract:
Interest in the culture of flatfishes has increased in recent years due to the high consumer demand for these fishes. The southern flounder, Paralichthys lethostigma, is the focus of important commercial and recreational fisheries in the south Atlantic and Gulf of Mexico. However, culture requirements of this species are poorly understood.
In 1996, two larval rearing studies were conducted with the southern flounder to: examine the effects three larval feeding regimes, and high and low light conditions have on survival, growth and pigmentation. At 24 C, five day old larvae (1.98 +/- 0.1 mm TL) initiated feeding on the rotifer, Brachionus plicatilis in black fiberglass tanks (three reps/trt) and completed metamorphosis by day 30. In treatment 1, larvae (6 dph) were fed rotifers (10/ml) days 6-15 and Artemia nauplii (3/ml) day 7 through metamorphosis. The second treatment was fed rotifers from 6 dph through metamorphosis and Artemia 7 dph through metamorphosis, while treatment 3 was fed using the same protocol as treatment 1 plus a commercially prepared larval diet (Zeigler Larva "Z" Plus). The three diet treatments were tested under high light (801 - 1820 lx) while treatment 1 was also tested under low light (42-387 lx) conditions.
Metamorphosis in all treatments began on day 23 (8.2 +/- 0.6 mm TL) and was completed one week later. No differences in size (11.4 +/- 1.2 mm TL) or percent survival (37.5 +/- 15.6) were detected. Similarly, no differences were detected in growth (11.7 +/- 1.3 mm TL) or percent survival (26.4 +/- 12.8) between larvae held in different light conditions. Partial and total albinism occurred in both studies and degree of pigmentation was divided into five categories that ranged from complete albinism to normal pigmentation.. No significant differences in percentage of normal pigmentation (26.5 +/- 14.0) were detected between different feeding regimes or light intensities.
(South Carolina Department of Natural Resources, Marine Resources Research Institute, P.O. Box 12559, Charleston, SC 29422-2559, USA)
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