T. I. J. Smith

Cultured shortnose sturgeon juveniles, age 11-330 days, were exposed to different salinity (0-35 ppt) and dissolved oxygen concentrations (2.0-5.0 mg/liter) in a series of experiments designed to examine tolerance levels. Tolerance to increased salinity improved with age. Fish 76 days old experienced 100% mortality in a 96-hour test when exposed to salinities ≥15 ppt while 330-day-old fish tolerated salinities as high as 20 ppt for a duration of 18 hours but exhibited 100% mortality at 30 ppt. Younger fish were also more susceptible to low oxygen concentrations than older fish. In a 6-hour...

Research and development studies involving red drum and hybrid striped bass culture in coastal ponds have been seriously impacted by avian predators, especially when overwintering was required. Studies were conducted at the Waddell Mariculture Center to document the effect of predation by birds and also to test various non-lethal control techniques. Use of pyrotechnics, flash tape, "evil-eye" balloons, aerial balloons, and various wire grid patterns over a pond offered only short term protection. Mortality of fish in ponds protected by these devices ranged from 42.0% to 99.7% depending...

During 1984-1992, 626 adult shortnose sturgeon (3.5 male:l female) were captured in the Savannah River. Significantly more fish were captured in the lower (rkm 42-75) than the upper (rkm 160-299) river. Radio telemetry data indicated that spawning appeared to occur upriver, between rkm 179 and rkm 278, and that the specific location and time of spawning varied annually. Some individuals spawned in consecutive years, but others apparently did not. Nonspawning fish appeared to remain in the vicinity of the fresh/brackish water interface (ca. rkm 30-40) throughout the spawning season. Most...

Fatty acid profiles of cultured hybrid striped bass and red drum were compared to their diets. Correlation coefficients were 0.94 and 0.98, respectively. Of the fatty acids examined, linoleic acid (18:2n6) levels were particularly high in cultured fish due to various dietary sources and extremely low in wild fishes. Such differences may be suitable to distinguish cultured from wild fish and may become another biochemical tool for use by law enforcement agencies involved in the protection and conservation of natural resources.

Two nursery trials were conducted in 0.I-ha ponds to examine effects of density on production of juvenile reciprocal cross hybrid striped bass (female Marone chrysops x male M. saxatilis). In 1986, 1.4-g hybrids were stocked at 5,000, 10,000 and 20,000 fishlha. In 1987, 1.7-g hybrids were stocked at 12,500, 25,000, and 37,500 fishlha. During the studies, the fish were fed a commercial trout feed (38% protein) several times per day. Aeration and water exchange were provided to maintain satisfactory oxygen levels. After approximately 280 days, fish were harvested. At harvest fish ranged from...