SRAC Publication No. 723 VI June 2000 PR Species Profile Bigmouth Buffalo Conrad W. Kleinholz1 Bigmouth buffalo are a popular backwaters or oxbows in foodfish and support a large rivers, often in flooded or veg- commercial fishery throughout etated areas. Bigmouth buffalo the lower Mississippi River val- are also common in large ley. Most “cultured” buffalo are reservoirs throughout the caught by commercial fisher- Mississippi River drainage. men and held in ponds until Their range extends from harvested and sold. Producing Manitoba and Saskatchewan buffalo in catfish ponds may in Canada, and from Montana now be economically feasible, to Ohio, south to Alabama and because market demand is west to Texas. The bigmouth increasing while commercial mostly eats zooplankton, but harvest is declining. Several also benthic insect larvae, live haulers transport buffalo crustaceans and detritus. from the Mississippi and Buffalo are excellent polyculture Cladocerans and copepods are the Arkansas Rivers to markets in candidates. By harvesting plank- preferred zooplankton forage, and Chicago, New York, Seattle, ton and detritus, bigmouth buffa- small zooplankters are eaten more Toronto and Montreal, and more lo can maximize feed efficiency in often than large prey such as of their customers are requesting intensively managed culture adult calanoid copepods. cultured fish. The reported 1998 ponds. Disadvantages include the There are three species of buffalo, harvest of buffalo was 22 million difficulty of sorting them at har- but only the bigmouth eats plank- pounds, and 94 percent of the har- vest and the increased labor ton. Producers should be able to vest was by gill nets and trammel required in processing a scaled identify and avoid smallmouth nets. Eighty-three percent of the fish. and black buffalo, which do not 1998 harvest was sold to African- perform as well as bigmouth buf- Americans. Six percent of the har- Life history and falo. All three species are common vest was from seining or culture to the Mississippi River drainage and was sold to Asians or central environmental requirements system and occur in both rivers Europeans. The growing market and reservoirs. for buffalo may indicate increased The bigmouth buffalo, Ictiobus per capita consumption or the fact The smallmouth buffalo, I. cyprinellus, has a maximum size of that in the last decade the Asian bubalus, has a small, ventral about 80 pounds (36 kg). It has a population in the U.S. has grown mouth. Its predominant diet is terminal, oblique mouth with thin more than 125 percent and the benthic macroinvertebrates and lips. There are more than 60 gill African-American population 13 some plant material. Smallmouth rakers (average of 72) on the first percent. buffalo are most often found in gill arch, and a single row of deep, clear pools in river systems. weakly developed pharyngeal The maximum recorded size is 15 teeth. Bigmouth buffalo occur 1 pounds (13.5 kg). Langston University, Langston, most frequently in slow-moving Oklahoma. The black buffalo, I. niger, also As the ponds are filled, add lime are observed along the shoreline. prefers riverine habitats and its (if necessary) to obtain an alkalini- If broodfish are not removed, they diet is similar to that of the small- ty above 50 ppm, and fertilize will compete directly with fry and mouth buffalo. Black buffalo have with 10 to 15 pounds per acre (13 fingerlings for zooplankton for- a ventral, slightly oblique mouth to 17 kg/ha) of 18-46-0 or similar age. with thick, fleshy lips. The black inorganic fertilizer. If surface buffalo is found in steeper gradi- water is used to fill the pond, it Hatchery production ent streams than either small- should be filtered through 125- Select broodstock and move them mouth or bigmouth buffalo. micrometer screening to eliminate to holding facilities in the hatch- Maximum weight of black buffalo predaceous zooplankton. Spawn- ery. Sperm should flow freely is about 35 pounds (16 kg). ing ponds should contain water from males when the abdomen is only a short time (usually 2 to 3 gently squeezed. Separate the days) before spawning to reduce Spawning techniques sexes in the holding facilities to insect predators and maximize control spawning. Inject females There are two types of reproduc- zooplankton production. See with carp pituitary (4 to 8 mg/kg) tion—traditional pond spawning SRAC publication 700, “Zoo- or a mixture of pituitary and HCG and hatchery production. Pond plankton Succession and Larval (Human Chorionic Gonadotropin, spawning is easy and requires no Fish Culture in Freshwater 2.5 to 5.0 mg/kg + 60 to 750 hatchery facilities, but the number Ponds,” for details. Stock brood- IU/kg, respectively) to induce of fry is unknown until finger- fish in the spawning pond while it final maturation, as mentioned in lings are sampled or sorted for is filling. Stock 15 to 18 fish per SRAC publication 425, “Hormone restocking in growout ponds. acre (37 to 44/ha), with a ratio of Preparation, Dosage Calculation, Hatchery production requires two males per female. Broodfish and Injection Techniques.” One more facilities, but fry production should be at least 2 years old and formulation of HCG is now can be carefully controlled. When weigh more than 3 pounds (1.4 approved for use with all finfish, fish numbers are known rather kg). The sexes are readily distin- but must be obtained by prescrip- than estimated, ponds can be guished because males develop tion from a veterinarian. The managed so the resulting finger- breeding tubercles over most of injections are given in two lings are the desired size for the body surface and usually pro- doses—an initial dose of 10 to 33 growout during the next season. duce milt when the abdomen is percent of the total, and a final Broodfish can be maintained with gently squeezed. Females have no injection within 6 to 8 hours. other fish during most of the year, tubercles; they have thicker bodies Buffalo will usually ripen within rather than kept in a separate than males and an enlarged, usu- 24 to 36 hours of the initial injec- brood pond. The broodfish will ally inflamed, vent during pres- tion. Dry strip the adults and fer- do very well in a polyculture pawning and reproductive peri- tilize the eggs in a plastic tub, pond at rates up to 200 per acre ods. Egg production is approxi- then add water to the tub and (500/ha), and will probably need mately 100,000 per pound allow eggs to harden for 2 hours. no supplemental feeding. If buffa- (250,000/kg) of body weight. Maintain at least 4 mg/L dis- lo broodfish are kept in a separate Eggs are approximately 1/16 inch solved oxygen in the water during pond, plankton populations can (1.5 mm) in diameter. Buffalo are hardening. After hardening, sepa- be maintained at desired levels by group spawners; the adhesive, rate the eggs by simply rolling occasional fertilization with inor- sinking eggs are scattered among them gently between the fingers. ganic fertilizers or low quality, flooded vegetation in water 1.5 to Then incubate them in hatching rotting hay. Broodfish also can be 4 feet (0.5 to 1.2 m) deep. Water jars. Other methods of separating fed slow-sink catfish pellets at 1 depth at spawning should be 3 to the eggs begin 1 to 5 minutes after to 2 percent of their body weight. 6 feet (0.9 to 1.8 m). the eggs are fertilized. One Pond spawning Adults can be induced to spawn method uses a saturated suspen- by quickly increasing water level sion of Fuller’s Earth, commonly Bigmouth buffalo spawn at water in a brood pond. If there is no sold as cat litter. Be sure to use a o temperatures of 65 to 75 F (18 to vegetation in the pond, add brand without additives or per- o 24 C). Pond spawning is most spawning mats or scatter a coarse fumes. Combine 2 to 4 parts by successful if spawning/nursery hay, such as Johnson grass, at the volume of the suspension per ponds are prepared ahead of edge of the pond. Coarse hay does part of eggs. Aerate the mixture time. Annual rye, wheat or rice not decay as quickly as grass hay with an airstone, and replace the can be planted during the winter or wheat or rice straw, so it does suspension every 10 minutes on the interior levees and bottoms not reduce the dissolved oxygen until the eggs are no longer sticky of dry ponds. The plants will in the vicinity of developing (probably at least 20 minutes). serve as spawning substrate and embryos or newly hatched fry. Then flush the suspension and green fertilizer when the ponds Fertilize the brood pond with hatch the eggs in hatching jars. are filled. Small ponds (0.1 to 1.0 inorganic fertilizer as for spawn- The Fuller’s Earth method is most acre; 0.04 to 0.4 ha) are easier to ing ponds. Move broodfish to effective when the total alkalinity manage than production ponds. another pond when schools of fry is less than 250 ppm. Other methods use salt and urea, fol- (100-mm) fingerlings during the essary. Harvest can be difficult in lowed by tannic acid, or tannic first season. Fry stocked at 5,000 polyculture systems, where there acid alone. For details, refer to per acre (12,000/ha) should grow are many sizes, species and SRAC publication 426, to 7- to 8-inch (175- to 200-mm) behaviors of fish. If harvest is “Techniques for Taking and fingerlings. done with catfish seines, do not Fertilizing the Spawn of Fish.” begin to sort the fish immediately Eggs hatch within 5 days at 65o F Pond production after seining.