The effect of detritus and ration size on the growth of Fundulus heteroclitus (L.)

Abstract

In a laboratory experiment using juvenile killifish, Fundulus heteroclitus L., detritus addition to a commercial fish food diet of 0, 2, 4, 6, 7, 10 and 14 % dry body weight/day did not significantly affect the growth of Fundulus when compared with replicate groups not receiving detritus. Even though Fundulus ingested detritus, they did not apparently use it for maintenance or growth. The fish required at least a daily ration of commercial fish food of 4–6 % dry body weight for maintenance. The ash content of fish fed at diets of fish food below 4 % dry weight/day increased, and the C N ratio decreased, indicating the inadequacy of these rations. Fish grew almost at field rates at higher amounts of commercial fish food. When feeding in the field, fish at above-maintenance rations must exert a strong influence on prey populations.