SRAC Publication No. 201

October 1997 VI Revision PR

Culture of Largemouth Bass Fingerlings

James T. Davis1 and Joe T. Lock2

Selection of brood fish condition often die before the cycle is complete. Producers of largemouth bass fin- The size of broodfish to use gerlings and stockers should be depends on facilities available. aware of the genetics of their The broodfish should be sexed brood stock. Though there may be during the late winter and males a desire to use brooders from off- separated from the females. hatchery sites, they should be Normally, smaller broodfish are from the local area under most sit- easier to handle and maintain. uations. Strain selection depends Males under 1 pound tend to on market demand and suitability mature earlier and grow faster for your market area. Florida Figure 1. These largemouth bass are all 1 year of age. Growth rate is largely dependent than females. Above this weight strains are popular in warmer on available food. females are normally larger for southern areas because they usu- fish of the same age. Some pro- ally grow to a larger maximum Largemouth bass broodfish can be ducers use older females for size. There are conflicting data on collected from wild sources, car- genetic reasons but fish 2 to 3 growth rates of Northern and ried over from year to year by the years of age and 12 to 18 inches in Florida strains. This is particularly producer or purchased from other length are normally the most true for growth during the first commercial producers.* Contrary dependable spawners. year. In addition, pure Florida to a popular myth, broodfish can strains are subject to winter-kill, Broodfish commonly lose 10 to 30 be collected by electro-fishing especially in shallow culture percent of their body weight dur- without causing reproductive ponds during prolonged sub- ing the spawning period. damage. Fish caught from the freezing weather. The use of scale Adequate food during the previ- wild will usually spawn during counts along the lateral line ous year is essential when the the first year of captivity but are and/or coloration are not reliable eggs are developing and for a not as dependable as bass ade- techniques for differentiating buildup of fat and muscle in the quately fed in culture ponds. A between the two sub-species. males. Supplemental feeding of thick tail, relatively small head, Positive strain identification live forage (baitfish) is usually and chunky appearance usually requires sophisticated elec- necessary unless the broodfish indicate good body condition. trophoretic techniques. Contact have been trained to take pelleted Good condition is essential the state Extension service for feeds. About 7 pounds of live for- because spawning and nest pro- information on electrophoretic age per pound of body weight is tection for several weeks without testing and strain recommenda- needed for annual maintenance. food is stressful, and fish in poor tions. For growth, 10 pounds of forage per pound of bass growth is 1Texas Agricultural Extension Service; required. Bass will eat almost any 2 *Check local regulations on collection and Texas Agricultural Extension Service possession. fish that they can swallow. The (retired). depth of the body of the forage Reduced spawning can occur in inch in length. Other management must be smaller than the size of late spring and early summer. techniques are the same. When the mouth of the bass. Tilapia*, Bass spawn as early as January in the number of fry being captured goldfish, and carps are commonly central Florida and February in becomes economically unfeasible, used because they can be pro- southern Texas, but most spawn- the ponds are drained and the duced in large quantities at low ing occurs in March and April in broodfish transferred back to the cost. When stocking forage fish the southern United States. holding ponds. The major advan- for bass, stock at intervals. Other- Separating the sexes and holding tage of this method is that the cul- wise, the forage may grow to be them until the water stabilizes turist can take advantage of multi- too large for the bass to swallow. above 60o F produces a more uni- ple spawnings. It is critical that Goldfish and carps often intro- form spawn. even-aged fry are stocked in the duce anchorworm and other par- rearing ponds to lessen cannibal- asites. Tilapia cost less to produce Stocking broodfish ism. and don’t normally transmit para- sites but are not available in the Stocking rates depend on whether Preparation of spawning the fingerlings will be sold direct- winter and spring. See SRAC or rearing ponds Publication No. 141, Forage Species ly from the pond, or the fry will Production Techniques, for culture be transferred to other ponds for Ponds should be rectangular, free information on these and other further growth. Stocking 30 to 50 of obstructions and no more than forage fishes. If pelleted feeds are pounds (10 to 40 fish) of brood- 6 feet deep to facilitate harvesting. used, at least 1 percent of the fish/acre to produce 20,000 to The ponds should be drained in body weight of the brood bass 50,000 fingerlings of 1.5- to 2-inch the fall and completely dried to should be fed daily including (marketable) size in the same eliminate predacious insects, fish- warm days during the winter. pond is commonly practiced in es, and diseases. The pond should private fish hatcheries. This be disked and sown to winter rye, Spawning method requires fewer resources, which will furnish a source of and less labor and technical organic fertilizer following spring Sexing is easiest in late winter or expertise. Approximately equal flooding. Apply agricultural lime early spring. Ripe females have a weights of males and females according to a soil test if the pond distended, soft belly and a red, should be stocked, which usually bottom soil is acidic. Heavy lime swollen vent. The scaleless area results in a higher number of applications, over 4 tons per acre, surrounding the vent is pear- males. Fingerlings are harvested will also harden soft soils and shaped in females compared to by seining small schools with a 1 reduce mud and associated toxins circular in males. The easiest and /8 inch- mesh seine or trapping in the harvest seine. Filamentous surest way to identify males is by and then subsequently draining algae commonly interfere with fry squeezing the abdomen. Ripe the pond. harvesting and must be con- males will emit a small amount of Broodfish are normally left in trolled. creamy white milt. Don’t confuse these ponds until harvest of the milt with clear urine emitted by Fill the pond with well water or fingerlings. Therefore, the brood- surface water filtered through 52 both sexes. If absolute certainty is fish are expected to be in the necessary, carefully insert a small mesh/inch saran socks. The pond ponds for about 65 days before should be filled only a few days capillary tube into the vent to being returned to the broodfish detect eggs or milt. (up to 14) before stocking to holding ponds. Some predation reduce the buildup of predacious Broodfish should not be subjected on the small bass by the adults is insects. Spawning ponds should to low oxygen conditions or sud- expected. In addition, the earliest be fertilized when spawning den temperature changes when spawns will normally devour any handling. To lessen stress to the spawns that hatch later. Unless fish, add salt to the hauling water larger fingerlings are to be pro- at about 2 pounds per 100 gal- duced, do not stock forage fish in lons. Handle the fish with soft, the spawning ponds as they inter- untreated, wet nets or by the fere with bass reproduction and lower lip as much as possible and are difficult to separate from bass handle gently, particularly the fry at harvest. gravid females. If the maximum numbers of fin- Largemouth bass begin spawning gerlings are desired, the rearing- in early spring when water tem- pond technique is usually used. peratures stabilize near 60o F. Up to 125 pounds of broodfish per Figure 2. A mixture of live forage fish is acre are stocked, and the fry are used as supplemental feeding. transferred to separate rearing For growth, 10 pounds of forage *May require a permit or be illegal in some ponds when they are 1/2 to 3/4 per pound of bass growth is states. required. activity is first noticed. The goal is fish is fueled by requirements for zooplankton production (cope- remedial stocking of ponds and pods and cladocerans). Zooplank- lakes. It has been reported that ton is produced from organic bass fed on pelleted rations will materials added to the rearing normally not grow above 10 inch- pond or from feeding on phyto- es in length without other feed plankton. Inorganic fertilizers are being available. usually added to stimulate phyto- Fingerling bass of about 3/4 to 1.0 plankton growth but are not inch long must be crowded in essential if enough organic fertiliz- tanks, raceways, or cages for feed ers are applied regularly. Some training. Crowding promotes culturists do not use inorganic fer- competition for food and better tilizer because it can stimulate fil- Figure 3. Bluegill make excellent continuous acceptance of pelleted rations. amentous algal growth. Others forage for bass. Grade closely to prevent cannibal- believe phytoplankton blooms, ism. Good water quality and dis- resulting from added nutrients, fore, most fingerlings are sold ease prevention are essential. enhance fry survival because of before they reach this size. Grow- reduced visibility. out to larger sizes is impractical Fingerlings should be fed 1.0 to for most culturists. The use of live 2.5 mm diameter moist pellets at Organic fertilizers should have a least 8 times per day including low carbon/nitrogen ratio for forage for growout is expensive and survival of the bass to stocker night feedings, 7 days per week. quick decomposition. Cottonseed Mixing ground fish with the feed meal produces excellent results size under this regime has been erratic. sometimes improves acceptance. and is the most widely used By gradually reducing the amount 1 organic fertilizer in bass rearing Fry seines should be of /32- or of ground fish, the fish can be 1 ponds. Some producers use alfalfa /16-inch soft mesh. Mud lines are weaned to a prepared diet. meal at 250 pounds per acre ini- not recommended. Seines 10 feet Researchers at San Marcos tially and then use 100 pounds long and 4 feet deep are sufficient National Fish Hatchery and per week to maintain the bloom. to surround most schools. The fry Training Center found that Cow manure and other animal are corralled into a seine pocket Biodiet® produced excellent manures will also give satisfactory and then either dipped with a fine results. Feed at least 15 percent of results but care must be taken to soft mesh net into a tub of water, body weight daily during the insure that fresh manure does not or the seine pocket is reversed training period. Grading is peri- adversely affect the ammonia con- into the tub for transfer. Fry num- odically necessary to maintain centration in the water. A general bers can be estimated by water uniformity and minimize canni- rule is to apply 50 pounds of cot- volume displacement or by balism. Pellet size can be tonseed meal/surface acre/week. weight-counting with accurate increased corresponding to fish Reduce applications if filamentous scales. Stock rearing ponds with growth. From 65 to 95 percent of or bluegreen algae proliferate. 50,000 to 70,000 fry per acre to the initially stocked fish should High phosphorus liquid inorganic produce 1.5- to 2-inch fingerlings. learn to take prepared feeds and fertilizers such as 10-34-0 stimu- Fry will normally remain in these should double in weight before late phytoplankton. Dilute liquid ponds from 14 to 28 days depend- transferring to growout ponds. ing on water temperature, and fertilizers at least 10:1 with water Feed-trained fish can be stocked to prevent sinking to the bottom survival to harvest should be from 70 to 95 percent. The need in growout ponds at rates of and stimulating filamentous algal 10,000 per acre or more depend- growth. Apply 1 gallon of fertiliz- for fry uniformity cannot be overemphasized. Stocking mixed ing on the size of “stockers” er/surface acre and repeat as nec- desired. They can also be grown essary to maintain a desirable sizes results in poor survival due to cannibalism. out in raceways or cages. Stocking plankton bloom. These are general density in these intensive culture recommendations and the produc- Use of artificial food for systems varies with water er must adjust fertilization rates exchange rate, oxygenation, and based on pond conditions. growout of ÒstockersÓ filtration. Fry transfer and rearing Largemouth bass don’t normally Floating mats, hay bales, flowing accept artificial feeds but can be water, or other methods to con- Transferred fry are more uniform trained to do so. This method has centrate fish for feeding acceler- in size if individual schools are not been widely practiced by com- ates in-pond feed acceptance. seined. All fry should be the same mercial producers but is useful in Feed a 2 to 3 mm pellet several age, as nearly as possible, because culturing larger fingerlings and times per day for a week or more. fingerlings become cannibalistic at “stocker” bass of 4 to 8 inches in Feed all that the fish will eat about 2 inches in length. There- length. The demand for this size which should be about 15 percent of stocked weight daily. The rate Economics of fingerling Production costs vary with the will gradually drop to about 5 production techniques used. Bass production percent daily. When the fish reach is normally only a part of a sport- about 4 inches, a high quality dry Largemouth bass fingerling pro- fish fingerling operation. Costs ration can be substituted to reduce duction can be profitable if mar- must be prorated among species cost. Bass should average 6 to 8 kets are available. Most finger- to estimate return on investment. inches in length in about 100 days. lings from commercial hatcheries Market success and price largely More than 80 percent survival and are sold directly to fisheries man- determine profitability. a 1.5:1 food conversion can be agers to stock private lakes or to The following is a sample budget expected. pond owners to stock their ponds. for a 1-surface-acre bass produc- Competition from public hatch- Though fingerling largemouth tion pond. Equipment costs are eries limits these markets in some bass are fairly easy to move, with prorated for a 20-acre sportfish states. Some producers market few death losses, the larger grown fingerling operation. A simple bass wholesale to fingerling dis- out “stockers” require much more production system of stocking tributors and avoid the challenges care in handling and transporting. broodfish and rearing fingerlings of dealing with fish sales to indi- Information on these techniques is in the same pond is used. This viduals. available in SRAC publications technique gives variable results 390-394. Since 1- to 2-inch bass fingerlings but is usually successful using are subject to severe cannibalism, minimal labor and technology. it is critical to harvest and sell The production is sold wholesale. them as soon as they reach mar- Selling retail would more than ketable size. Wholesale arrange- double returns. ments must be made in advance if all the production cannot be sold on the retail market in a short period of time.

Projected Income and Expenses from Largemouth Bass Fingerling Production in 1-Surface-Acre Pond Projected Income 30,000 1.5- to 2-inch fingerlings at $0.15 = $4,500 Expenses Variable costs Fixed costs Net Return to Management $1,998 Broodfish Depreciation (40 lbs @ $8/lb) 320 Other costs Pond construction Cottonseed meal (500 lbs ($4,000-10 yrs) 400 Insurance 50 @ $30/100 lbs) 150 Truck, one ton 200 Taxes (except income tax) 10 Water pumping (4 ac ft @ $30/ac ft) 120 Service roads 10 Labor (75 hrs @ $5/hr) 375 Well/pump 200 Interest on capital outlay 500 Fuel 100 Seines 10 Total costs $2,502 Total variable costs $1,065 Transport tank 2 Holding facility 50 Other equipment 5 Total fixed cost $877

The work reported in this publication was supported in part by the Southern Regional Aquaculture Center through Grant No. 94-38500-0045 from the United States Department of Agriculture, Cooperative State Research, Education, and Extension Service.