11 



(2.44 meters) square and 6-feet (1.83 meters) deep, suspended 

 to provide a cage depth of about 3 1/2 feet (1.07 meters). 

 The cage was divided by 1/4-inch-mesh (6.4-millimeter mesh) 

 hardware cloth to provide two equal compartments. On May 16, 

 1969, one compartment was stocked with 780 individuals having 

 a total weight of 196.6 pounds (89.2 kilograms), a mean weight 

 of a 0.25 pounds (114 grams); the other compartment received 

 an equal number of a smaller size. To provide a basis for 

 comparison, smaller cages were placed in two ponds (numbers 10 

 and 12) and stocked with fish of the same size as the largest 

 used in the lake, and at the same cage density. Sufficient 

 additional fish were released into these small ponds to raise 

 the total density within the ponds to a level of 1,500 fish 

 per acre (3,707 fish per hectare). All populations in this 

 test were fed the same rations used for the caged populations 

 in our 1-acre (0.4-hectare) ponds. 



Results . --The fish in the cage in Forbes Lake began 

 to mutilate one another, and to show an increased mortality, 

 after the same time interval (about 80 days), and in an 

 identical fashion, to the caged fish in two of our 1-acre 

 (0.4-hectare) ponds. Surprisingly, however, mutilation was 

 not observed, and mortality rates were much lower in cages 

 floated in ponds 10 and 12, than in the fish caged in the 

 lake. Because of the late season loss of weight and high mor- 

 talities among the fish caged in the lake, we found that 

 weights recorded from the populations in August, before the 

 mortalities occurred, provided the best basis for comparison. 

 In Table 4 we may see that the larger of the two sizes of fish 

 caged in the lake had an average weight of 0.81 pounds 

 (366.5 grams) on August 13, compared to weights of 0.65 and 

 0.59 pounds (294 and 268 grams) in ponds 10 and 12 respectively, 

 at the later date of August 27. Thus, growth was apparently 

 not inhibited or limited by the pedestrian traffic on the dock, 

 or by the passing of boats with outboard motors in this most 

 congested area of the lake. In two subsequent tests under the 

 same conditions it was established that good growth and sur- 

 vival could be obtained, and "fighting" eliminated, by use of 

 a more complete feed, but the feeding was done by others and 

 the feeding rates not sufficiently controlled to provide 

 quantitative data. Fish from these tests released into the 

 lake were quite readily caught by anglers, but creel records 

 could not be obtained. 



