S

Bull MinnowFundulus Grandis

A.K.A. Gulf Killifish, Mud Minnows

Fundulus grandis

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

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

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

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

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

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

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

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

Sexual Dimorphism in F. grandis• Females larger than

males

• Males have more coloration than females

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

Pros and Cons to Culturing F. grandis

Advantages

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

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

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. Cortney Ohs (University of Florida) http://miami-dade.ifas.ufl.edu/environment/documents/

aquaculture/Ohs_Marine%20Baitfish_Overview.pdf