Bull Minnow Aquaculture LaDon Swann Auburn University Mississippi-Alabama Sea Grant Consortium

Bullminnow Aquaculture Scientific Name Scientific Name – Fundulus grandis Common Name Common Name – Gulf Killifish Regional Names Regional Names – Bullminnow - Alabama – Mudminnow - Texas – Cocahoe Minnow - Louisiana – Mummichogs - East Coast (F. heteroclitus)

Bullminnow Characteristics Estuarine resident Estuarine resident – Shallow waters of oyster bars, tidal creeks, salt marsh pools, and bayous. Sexes Sexes – Females - uniform greenish silver, darkening from bottom to top. – Males - Darker green with prominent gold speckling. Black patch ventrally along gill flap when ready to spawn.

Bullminnow Characteristics Spawning Spawning – External fertilization – Fractional spawners – Exhibit semilunar spawning cycles – Adhesive eggs – Spawning above 68 o C. – Spawn March to October. – Peak spawn - March and April – Minor peak- late August to early September

Aquaculture Candidate? Advantages Advantages – Popular live baitfish used to catch: n Flounder n Speckled Trout n Redfish – Price n Wholesale -$70-$100/1000 or $7-10/lb. n Retail -$1.50-$2.50/dozen or $12-20/lb.

Aquaculture Candidate? – Hardy n Tolerates wide range of water quality. n Handling stress is minimal n Low mortality at retail level n Long-lasting on the hook – Rapid growth n Spawn to Harvest - 2 to 6 months

Aquaculture Canidate? Disadvantage Disadvantage – Need large number of broodfish. n Females produce a relatively low number of eggs compared to other culture species. – eggs per spawn –up to 1200 eggs per spawning season

Supply & Demand Demand >>> Supply Demand >>> Supply – April, May, June Demand>Supply Demand>Supply – July, Aug, Sep

Important Considerations Water quality Water quality – Salinity (single most important factor) n >=5 ppt for efficient growth and production. – Dissolved oxygen n Generally above 4.0mg/L

Important Considerations Pond design Pond design – Small size (1/4 acre) or narrow for easy seining. – Average depth - 1 meter. – Smooth bottom for seining. – Graded for complete drainage. – Catch basin for harvest. – Free of aquatic vegetation

Production Systems Three-pond system Three-pond system – Brood Pond – Hatching Pond – Grow-out Pond ¼ acre brood pond ¼-1 acre hatching pond 1-5 acre grow-out pond

Brood Pond Stock brood fish in January at 10,000 fish/acre. Stock brood fish in January at 10,000 fish/acre. 2:1 females:male. 2:1 females:male. Feed high-protein feed at 3% body weight per day. Feed high-protein feed at 3% body weight per day. Add spawning mats when water temperature reaches 68 o C. Add spawning mats when water temperature reaches 68 o C.

Spawning Mats Place in shallow water at pond edges. Place in shallow water at pond edges. Use PVC trellis to keep spawning mat off bottom. Use PVC trellis to keep spawning mat off bottom. Remove after 1 week. Remove after 1 week. Estimate eggs. Estimate eggs. Transfer to hatching pond. Transfer to hatching pond. Limit transfer to 2 week period for uniform fry size. Limit transfer to 2 week period for uniform fry size.

Hatching Pond Filter incoming water. Filter incoming water. Fertilize 40lbs/acre Fertilize 40lbs/acre Treat pond for air-breathing insects. Treat pond for air-breathing insects. Stock with 1.5 million eggs/acre. Stock with 1.5 million eggs/acre. Eggs will hatch in 2 to 3 weeks. Eggs will hatch in 2 to 3 weeks. Expect 1 to 1.2 million fry. Expect 1 to 1.2 million fry. Feed high-protein minnow feed at 5lb/acre/day. Feed high-protein minnow feed at 5lb/acre/day. Stock fry to grow-out ponds when they reach 0.5 grams or 1000 fish/lb. Stock fry to grow-out ponds when they reach 0.5 grams or 1000 fish/lb.

Grow-out Pond Stock fry at a rate of 50,000 to 200,000 fish/acre. Stock fry at a rate of 50,000 to 200,000 fish/acre. Stocking density Stocking density – dependent on market size. – Higher rates means smaller fish at harvest Feed Feed – 10% of stocked wt/day for 10 days – 5% body weight there after. Sample fish every 2 weeks and adjust feed accordingly. Sample fish every 2 weeks and adjust feed accordingly.

Production Systems Two-pond system Two-pond system – Brood Pond – Hatch and Grow-out Pond Leave eggs in ponds Leave eggs in ponds – Fewer ponds – Less control of densities ¼ acre brood pond 1-5 acre hatching/grow-out pond

Harvest Partial Harvest Partial Harvest – Trap – Seine Complete Harvest Complete Harvest – Drain

Post-Harvest Place fish in holding tank for 24 hr without feed. Place fish in holding tank for 24 hr without feed. – Get accurate weights and counts. – Recover from handling stress. – Purge gut contents which minimizes water fouling during transport.

Delivery or Pick-up? Survey of bait dealers suggest they would pay the same price for pick-up or delivery. Survey of bait dealers suggest they would pay the same price for pick-up or delivery. – Cost savings to wholesaler if the bait dealer picks-up his fish. n Fuel cost n Labor cost n Liability for the product n Concentrate efforts on harvest and supply