Laserfiche WebLink
1 <br />' Thus, squawfish were probably still limited by inadequate forage although <br />temperatures were nearly optimal for growth. <br />' In 1988, no predator vs. prey size comparisons were made. However, it <br /> appeared that, though there was a limited number of fathead minnows of <br /> suitable size present, all carp were still of the 1986 year-class and were <br /> too large to be available to any of the squawfish. The one squawfish with <br />' food in i ts stomach captured on 15 June did contain a fathead minnow. <br />Thus, although availabilty of forage fish might have improved, low squaw- <br />fish condition (K = 0.58) at this time indicated otherwise. <br />Survival <br />General. Obtaining samples of squawfish for growth analysis became more <br />difficult over time, indicating an increasing scarcity of squawfish in <br />Fish Chalet Pond. During 14-17 September 1987, we fin-clipped squawfish <br />and conducted a Peterson mark-recapture population estimate, as modified <br />by Chapman (1951), on 29 September. The estimate was 107 remaining squaw- <br />fish (95% confidence interval = 80-135). Thus, of the 7,000 stocked on 31 <br />August 1986, only 1.5% survived to 29 September of the following year. In <br />1988, we seined the pond monthly from April through July and caught no <br />more than three squawfish during any effort. No squawfish were found in <br />t September 1989 when we rotenoned the pond; thus, squawfish in Fish Chalet <br />Pond suffered 100% mortality over the 3-yr period. There were no large <br />predacious fish present, so mortality would have resulted from the follow- <br />ing possible causes: cannibalism, bird predation, disease, starvation, <br />poor water quality, or some combination thereof. <br />Predation. Other than the squawfish, there were no predacious fish <br />' present in Fish Chalet Pond. Great blue herons (Ardea herodias) were <br />16