Production of Gulf Killifish in the Black Belt Region of Alabama Using Saline Groundwater

Abstract

AbstractThe Gulf killifish Fundulus grandis, commonly called the bull minnow, mudminnow, or cacahoe, is a popular live bait along the Gulf of Mexico coast in the United States. Although culture techniques for Gulf killifish have been established for more than 30 years, this species is not commonly produced. Suitable coastal areas are thought to be one of the limitations. Low‐salinity groundwater occurs in much of the United States, including portions of the Alabama Black Belt region; however, the relative abundance of minerals in the water varies. Spawning success was compared among Gulf killifish held in saline groundwater (salinity = 4.2–11.1‰) from four inland sites and in 5‰ synthetic seawater. Gulf killifish production (fry to subadult) was compared between two sites of similar salinity but with different mineral profiles (site A had 4.0‰ salinity and received water from a fertilized source pond; site B had 3.2‰ salinity and received water with no fertilizer additions); initial stocking densities in 1.15‐m2 outdoor tanks were 25, 50, and 100 fry/m2. Gulf killifish spawned successfully under all conditions tested. Mean (±SD) fry production of 1.7 ± 0.88 fry/g of female was obtained. The yields and mean weights obtained differed by site and stocking density. After 104 d of production, the highest yield was 133.3 ± 40.4 g/m2 (1,333 ± 404 kg/ha) at site A for fish stocked at 100 fry/m2. The yield at site B for fish at the same stocking density was 62.6 ± 18.8 g/m2. Market‐sized fish (total length ≥ 6.35 cm; weight = 3.3 g) were obtained at site A for the stocking density of 25 fry/m2, but market‐sized fish were not obtained for any stocking density at site B. Although the mineral profiles differ between saline groundwater and natural seawater, saline groundwater is suitable for the reproduction and growth of this species. Egg production and fish growth were similar to levels expected for Gulf killifish culture in brackish‐water ponds along the Gulf of Mexico coast.