No abstract

Investigations concerning spawning, hatching, and grow‐out of gulf killifish (Fundulus grandis) were conducted in 0.08‐ha, brackish‐water ponds at Alabama's Claude Peteet Mariculture Center during 1979. Adult gulf killifish stocked at 88,750 fish/ha and a 1:1 sex ratio in 3 spawning ponds deposited 499,777 eggs on 1,001 Spanish moss mats placed around pond margins between 1 March and 13 August. Rate of egg deposition was highest in March (4,103 eggs/day/pond) and lowest in July and August (36 eggs/day/pond). A total of 293,467 eggs and 416 mats transferred to 3 hatching ponds between 13 March and 8 May produced 219,921 juvenile killifish (75% survival) averaging 0.5 g at harvest on 6 June. Production and feed conversion in hatching ponds averaged 413.90 kg/ha and 1.9, respectively. Stocked on 6 June in 4 grow‐out ponds each at either 250,000 or 370,000 fish/ha and fed either 2 or 3 times daily, the juvenile gulf killifish reached marketable size (2.4 g and 57 mm total length) in 49 days. Production in grow‐out ponds averaged 658 kg/ha with 93% survival and 2.4 feed conversion. Analysis (2 × 2 factorial) of grow‐out data indicated no significant differences for effects of densities and feeding on mean weights of fish at harvest.

Bull minnows are used extensively as live bait along the northern coast of the Gulf of Mexico. Fish used in this industry are generally trapped from marsh pools or seined from open bodies of water. Since the species is not available from commercial hatcheries, supply rarely meets demand. Experiments at Claude Peteet Mariculture Center, Gulf Shores, Alabama demonstrated the capability of Fundulus grandis to spawn in brackish water ponds, utilize commercial fish feeds, and produce economical gains in grow‐out ponds. Standing crops of 570.3 kg/ha of marketable fish were produced in a pond stocked at 125,000/ha receiving supplemental feeding and 249.5 kg/ha from one pond stocked at 62,500/ha receiving only applications of organic fertilizer. This production was attained in 95 and 82 days of culture from the fed and unfed ponds, respectively. Observations on spawning activity are made.

Studies were conducted seasonally from 1975–1977 in 0.08 ha, brackish water ponds at the Claude Peteet Mariculture Center on monoculture of Florida pompano (Trachinotus carolinus), brown shrimp (Penaeus aztecus), and white shrimp (P. setiferus), and on polyculture of pompano with pink (P. duorarum) or brown shrimp. Three methods of stocking polyculture ponds were investigated. Pompano production from monoculture ponds manages eeasonally for 95 to 191 days averaged 564 kg/ha with mean survival of 42%, mean feed conversion of 3.0, and mean weight of 156 g. During one growing season in 1977, consecutive 75‐ to 81‐day crops of brown and white shrimp produced mean yields of 349 and 600 kg/ha, survivals of 69 and 96%, feed conversions of 4.0 and 2.3, and weights averaging 8.3 and 10.0 g, respectively. The optimal method of stocking polyculture ponds with pompano and shrimp produced mean yields of 593 and 222 kg/ha, survivals of 30 and 53%, feed conversion of 2.6, and weights averaging 185 and 13.5 g, respectively. Although one season's highest yield (949 kg/ha, mean) was from 2 successive crops of penaieds and the maximum yield of pompano (760 kg/ha) was in monoculture, polyculture of shrimp and pompano demonstrated both technical and economical potential.

High costs of commercially produced feeds coupled with high conversions of feed to fish flesh inflates the production cost of marine fish and shellfish and subsequently reduces the opportunity for profit to the potential mariculturist. This paper summarizes the results of tests conducted utilizing a diet of inexpensive ground industrial fish mixed with soybean meal and compares the growth, mortality and efficiency of fish receiving this diet to those receiving a diet of commercially produced trout chow. Discussed also are techniques used in capturing and rearing young pompano for the tests as well as actual cultural techniques.