Bull Minnow Fundulus Grandis

1. Bull MinnowFundulusGrandis A.K.A. Gulf Killifish, Mud Minnows

2. Fundulusgrandis • Member of the Fundulidae family, topminnows • Native to the Gulf of Mexico from Texas to the Keys, the eastern coasts of Florida and Cuba • Grows up to 18 cm • Favorite prey item of sport fish including flounder, speckled trout, and red snapper

3. Reproduction in Captivity • Reproduces well in captivity • Females don’t produce as many eggs as other cultures species • Egg adhere to spawning mats • Need large amount of spawners and space • Peak spawning from March-April and August-September

4. Production Methods:Spawning Pond • A pond devoted to egg production • 10,000 fish per acre • 2 females for every 1 male • Stock pond during January to February • When waters are warm (above 68ºF), spawning mats are placed along the edge of pond • Females attach eggs to bottom of mats

5. Production Methods:Hatching Pond • Pond dedicated to hatching fish and growing fry • No wild vegetation or fish in the pond • Water must be filtered through 285 µm mesh • 1.5 million eggs can be loaded with 1 million expected to hatch • 1 week before loading pond, 250lbs/acre of dried chicken manure should be added

6. Production Method:Growing Pond • Juveniles are moved to finish growing to harvestable size • Transfer to growing pond when 900-1,500 fish/lb • Density dictates how large the fish grow • 50,000 fish/acre=2.5” fish in 5 weeks • 100,000 fish/acre=2.5” in 6+ weeks • When harvestable size, fish are removed by draining the pond and seining for them

7. Economic Enterprises • Sport fishing brings in billions of dollars to state’s economies • Demand for bait is high • Sold as live bait for flounder, speckled trout, and redfish • ~$11/lb for wholesale and ~$34/lb for retail • Wild stock typically relied upon but experimenting (successfully) with culturing

8. FOOD!!! • Bull minnows are om-nom-nom-nivores and will eat what’s avaliable • Phase 1 fish are fed small floating pellets 2x a day at 3% body weight/day • Once hatched, fish are fed ground minnow meal, 28-32% crude protein, 5lbs/acre/day • Phase 3 fish are fed floating pellets 2x a day at 10% body weight/day • After 10 days, feed decreases to 5% total weight. • After 2 weeks, decreased to 3% total weight. • Feed should not exceed 25lbs/acre/day

9. Life Cycle and Larval Stages • Spawning occurs in marsh vegetation • Lives in shallow waters of salt marshes, mangrove swamps, oyster beds, etc. • External fertilization • Eggs can tolerate exposure to air and can be kept in moist containers • Reaches sexual maturity around 1.6-2.0” • Lives up to 4 years (5.5”), few survive to 3 years • Sexually dimorphic

10. Sexual Dimorphism in F. grandis Females larger than males Males have more coloration than females

11. Chemical and Environmental Requirements • Brackish water from 5-30 ppt, lower salinity affects growth and immunity • A few shallow, 1m ponds with properly sloped bottoms • Water needs to be fertilized to stimulate natural foods (plankton) • For aquatic insect treatment, 2 pints/acre of diesel and 2 gal/acre is added before stocking • Surprisingly, some states don’t like you to do this

12. Pros and Cons to Culturing F. grandis Advantages Disadvantages Costly to start up and maintain Low number of eggs produced by females Dependent on market demand and time of year In grand scheme of aquaculture, little is known about culturing bull minnows • Very tolerant of water qualities • Low mortality rates and high fish health • Stays alive in transport and on a baited hook • Fast growing and uniform sizing

13. Acknowledgements • Southern Regional Aquaculture Center (Texas A&M) • http://fisheries.tamu.edu/files/2013/10/SRAC-Publication-No.-1200-Growing-Bull-Minnows-for-Bait.pdf • Auburn University Marine Extension and Research Center • http://www.extension.org/mediawiki/files/2/24/Growing_Bull_Minnows_in_Alabama.pdf • Dr. CortneyOhs(University of Florida) • http://miami-dade.ifas.ufl.edu/environment/documents/aquaculture/Ohs_Marine%20Baitfish_Overview.pdf