Definitions; Descriptions of major catfish species; Channel catfish; Blue catfish; White catfish; Flathead catfish; Bullheads; History of propagated catfish; Descriptions of catfish stocks; Farm stocks; Hatchery and introduced stocks; Research stocks; Catfish breeding programs; Strain evaluation; Crossbreeding; Hybridization and polyploidization; Mass selection and inbreeding, Cellular genetics; Genetic data and performance records for research strains of catfish.

The number of largemouth bass (Micropterus salmoides) in a 3.5-acre experimental pond located at Auburn University Agricultural Experiment Station was estimated by mark and recovery techniques using both Schnabel and Peterson methods. Sampling was done with both electric shocker and angling. Estimates were made during two periods in 1962. Various estimates of the number of bass made in this study were fairly uniform. However, on draining the estimates were found to be in error by approximately 50 percent. Based on number of bass recovered at draining and the computed percentage of survival, the value of N for the first period (May 23, to December 20, 1962), was computed to be 604 bass, whereas the Schnabel and Peterson methods gave N values of 304 bass and 469 bass with percent errors of -49.7 and -22.4, respectively. The theoretical requirements of both methods seemed to be met for the first period. The value of N for the second period (August 1 to December 20, 1962) was computed to be 500 bass, whereas the Schnabel and Peterson methods gave N values of 381 bass and 313 bass with percent errors of -23.8 and 37.4, respectively. The requirements of no mortality for the Schnabel method was violated without any apparent loss of accuracy. Only with the Peterson method during the first period were the criteria of Robson and Regier (1964) satisfied for censuses with management applications. None of the censuses met their criteria for censuses with research applications.

Three populations each of Oreochromis aureus and O. niloticus, one each of O. mossambicus and O. urolepis hornorum, and two each of red tilapia derived from hybridization of O. urolepis hornorum females and O. mossambicus males were compared for the electrophoretic mobilities of their enzymes at 27 enzyme loci using horizontal starch gel electrophoresis. Variation was sufficient to differentiate the species but not all of the populations surveyed. Dichotomous keys based on relative electrophoretic mobilities of isozymes were developed for the identification of the species. The primary diagnostic loci were AAT [Aspartate Amino Transferase], EST [Esterase] and SOD [Superoxide Dismutase] in the liver and EST and GPI [Glucose Phosphate Isomerase] in the eye. Red tilapia had a high frequency of alleles from O. mossambicus, followed by O. urolepis hornorum, with low frequencies of O. aureus and O. niloticus.

This paper deals with the methods used in overwintering large numbers of tilapia indoors. The facilities, stocking procedure, feeding and care of fish, treatment for parasites, and cost are reported.

A population of red tilapia with cold tolerance traits similar to Tilapia aurea has been produced using introgressive breeding techniques, i.e., hybridization (female T. aurea x male red tilapia, heterozygous for red trait) followed by backcrossing (female T. aurea x F-1 male, red phenotype). Progeny of the F-1 backcross, consisting of approximately 50% normal and 50% red phenotype, survived longer under conditions of ambient cooling than either T. aurea or T. mossambica (P 0.05). There were no differences in cold tolerance between the normal and red phenotypes of the F-1 backcross population (P 0.05). Mean lower lethal temperatures for the three groups were: T. aurea (11.6 °C), T. mossambica (13.8 °C), and F-1 backcross, red and normal phenotypes pooled, 10.0 °C.

Brood stock of basses were obtained from the following locations during March to April, 1969; Micropterus coosae (Alabama race), Alabama River system; M. coosae (Apalachicola rate), Apalachicola River system; M. notius, Suwannee River system; M. punctulatus henshalli, Tallapossa River system; M. p. punctulatus, Apalachicola River system; M. dolomieui, Mammoth Spring National Fish Hatchery, Arkansas. Adult bass of each stock except Suwannee bass spawned during April 5 to May 19, 1969, in 0.04-to 0.1-acre earthen ponds when stocked at 50 to 100 per care. Suwannee bass possibly had already spawned in their native habitat. However, Suwannee bass spawned in April during both 1970 and 1971. Surface water temperatures and dates when eggs were first observed were as follows: M. p. henshalli-69 F (April 5, 1969) ; M. coosae (Alabama race)-73 F (April 14, 1969) ; M. dolomieui-73 F (April 16, 1969) ; M. p. punctualatus-74 F (May 3, 1969) ; M. coosae (Apalachicola race)-79 F (May 5, 1969) ; M. notius-68 F (April 9, 1970), and 68 F (April 17, 1971). Egg sizes varied considerably among species, M. p. henshalli having eggs 1.9 mm in diameter, while the smallest of adult basses, M.coosae (Alabama race) had the largest eggs at 3.5 mm in diameter. Fry from each bass form except M. notius were stocked during May 9 to June 11 into 0.1-acre ponds which contained abundant fathead minnow, Pimephales promelas. Bass were 17 to 41 mm in total length and were stocked at rates of 800 to 3,000 per acre. Rates of growth varied with species and stocking rate, and survival at draining was lowest in M. dolomieui (63.7 per cent) and highest (89.9 per cent) in M. coosae (Apalachicola race). Another experiment was a comparison of growth of M. henshalli, M. coosae (Alabama race), M. coosae (Apalachicola race), and M. dolomieui, in a single fertilized pond. In the pond, survival of the Alabama redeye bass was 100 per cent, while that of the Apalachicola redeye bazz was only 67 per cent. The Alabama race had the least growth rate of the four basses. M. notius fry stocked at 25 mm (272/A) on May 21, 1970, into a pond containing abundant fathead minnow forage grew to 94 mm by July 13, 1970. All fish were lost at this time from oxygen depletion.