Open AccessA Practical Calcium Hardness Criterion for Channel Catfish Hatchery Water Supplies
Author(s) -
Tucker Craig S.,
Steeby James A.
Publication year - 1993
Publication title -
journal of the world aquaculture society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.655
H-Index - 60
eISSN - 1749-7345
pISSN - 0893-8849
DOI - 10.1111/j.1749-7345.1993.tb00171.x
Subject(s) - calcium , catfish , hatchery , biology , zoology , ictalurus , hard water , fishery , spawn (biology) , broodstock , aquaculture , chemistry , fish <actinopterygii> , metallurgy , materials science , organic chemistry
Three pairs of brood channel catfish Ictalurus punctatus were induced to spawn in aquaria supplied with flowing water from a reservoir filled with ground water (calcium hardness = 110 mg/L as CaCO 3 = 44 mg/L as calcium). Fertilized egg masses were allowed to incubate in aquaria for 6 h and each mass was then split into five portions. The five portions were then allowed to hatch and the resulting sac fry developed in waters with calcium hardnesses of 0, 1, 5, 10, or 100 mg/L as CaCO 3 (0, 0.4, 2, 4, or 40 mg/L as calcium). Test waters were prepared from distilleddeionized water and reagent‐grade chemicals; tests were conducted using static‐renewal conditions. Survival from hatch to onset of exogenous feeding (“swim‐up”) averaged 62% in calcium‐free water and 98% at all other calcium hardness levels. Wet weight gain, dry weight loss, and resistance to environmental hypoxia were significantly affected ( P < 0.05) by environmental calcium levels: best growth, yolk utilization rate (indicated by changes in dry weight and visual observation), and tolerance to low dissolved oxygen concentrations were found at calcium hardnesses of 10 and 100 mg/L as CaCO 3 . Based upon these results, a minimum calcium hardness of 10 mg/L as CaCO 3 (4 mg/L as calcium) is recommended for channel catfish hatchery water supplies.