362 FISH HATCHERY MANAGEMENT 



CHANNEL CATFISH 



Channel catfish have been safely transported at loadings presented in 

 Table 41. Experience will dictate whether or not the suggested loadings are 

 suitable for varying situations. If the trip exceeds 16 hours, it is recom- 

 mended that a complete water change be made during hauling. 



Catfish also may be transported as sac fry and in the swim- up stage. 

 Most transfers of these stages should be of relatively short duration. Oxy- 

 gen systems alone are satisfactory when fry are hauled, and have some ad- 

 vantages over the use of pumps because suction and spraying turbulence is 

 eliminated. If pumps and spray systems are used, the pump should be 

 operated at a rate low enough to minimize roiling of water in the compart- 

 ments. Sac fry, 5,000 per 1.5 gallons of water, have been shipped success- 

 fully in 1-cubic-foot plastic bags for up to 36 hours. Water temperature 

 should be maintained at the same level fry experienced in the hatchery. 

 Although it may be advantageous to gradually cool the water for shipping 

 some warmwater species, it is not recommended for channel catfish fry. 



Fingerlings of 1-6 inches ship well for 36 hours. As with salmonids, the 

 number and weight of fish transported varies in proportion to the size of 

 the fish and duration of the shipment. 



The following guidelines may be of value for hauling channel catfish: 



(1) Four pounds of 16-inch catfish can be transported per gallon of water 

 at 65T. 



(2) Loading rates can be increased by 25"o for each 10°F decrease in wa- 

 ter temperature, and reduced proportionately for an increase in tempera- 

 ture. 



(3) As fish length increases, the pounds of fish per gallon of water can be 

 increased proportionally. For example, a tank holding 1 pound of 4-inch 



Table 41. pounds of catfish that can be transported per gallon of fi5°F 



WATER. (SOURCE: MILLARD AND McCRAREN, UNPUBLISHED) 



NO. OF FISH TRANSIT PERIOD IN HOURS 



PER POUND 8 12 16 



1.0 6.30 5.55 4.80 



2.0 5.90 4.80 3.45 



4.0 5.00 4.1 2.95 



50 3.45 2.50 2.05 



125 2.95 2.20 1.80 



2.50 2.20 1.75 1.50 



.500 1.75 1.65 1.25 



1,000 1.25 1.00 0.70 



10,000 0.20 0.20 0.20 



