Bruce A. Manny
Gregory W. Kennedy
Thomas A. Edsall
2003
<p><span>Newly hatched </span>fry<span> were acclimated to 7 or 12°C and either fed daily (controls) or denied food for varying lengths of time and then fed daily until the end of the study (day 91 at 7°C and day 43 at 12°C). Growth was reduced by delays </span>in<span> the onset of feeding of 27 or more days at 7°C and 7 or more days at 12°C. Mortality of </span>fry<span> unfed for more than 34 days at 7°C, or more than 21 days at 12°C, was higher than among controls. Daily mortality increased with the length of the food deprivation period and did not cease immediately when food was made available, but reached zero by the end of the study. Mortality among unfed </span>fry<span> reached 50% </span>in<span> about 59 days at 7°C and 32 days at 12°C. Study results permitted calculation of the "point-of-no-return" (PNR) mortality, which included the mortality that occurred during the period of food deprivation, and also the delayed component of mortality that was directly attributable to </span>starvation<span> and that occurred after food was made available. The PNR for 50% mortality for food-deprived </span>fry<span> occurred after 52 days at 7°C and 24 days at 12°C. Thus, both measures of mortality indicate that </span>lake<span> </span>trout<span> </span>fry<span> would be highly resistant to death by </span>starvation<span> </span>in<span> the thermal habitat they would be expected to occupy </span>in<span> the Great Lakes. We conclude that a more likely adverse effect of reduced food availability would result from a reduction </span>in<span> growth rate that extends the length of time </span>fry<span> remain small and vulnerable to predation by adult alewives and other non-native fishes with which they associate.</span></p>
application/pdf
10.1016/S0380-1330(03)70444-4
en
Elsevier
Starvation resistance in lake trout fry
article