초록
잉어를 저밀도로 방양하고 동시에 사료중의 동물성단백질을 줄이는 실험을 하였다. 수면적 $454m^2$의 못 3개에 각 못에 평균 81.2g되는 보통잉어 72미와 평균 37.89g 되는 비단잉어 28미를 방양 189일간 사육한 결과, 동물질 $20\%$ 사료의 못에서는 보통잉어가 평균 776.2g, 비단잉어 평균 $504.2g$, 총평균, 701.1g으로 자라고, $35\%$구에서는 각각 792.9g, 539.1g, 730.1g, $50\%$에서는 각각 983.7g, 630.4g, 887.0g으로 자랐다. 이 실험에서 1ha당 생산고가 $20\%$구에서 1,352kg, $35\%$구에서, 1,495kg, $50\%$구에서 1,447kg였으므로 양어지에서의 보통생산고의 1/2에 미달되었으며 이 정도의 저밀도양어에서는 사육단백질의 량을 감소시켜서는 안된다는 결론이 나온다.
An experiment on the growth of common carp by feeding low (animal) protein feed when stocked at a rotatively low rate of density was conducted in 1976 at the fish pond of the National fisheries University of Busan. Three ponds averaging $454m^2$ were used with rations of different combinations of feed in respect to protein content. Each pond was equally stocked with 72 general common carp averaging 81.2g and 28 colored common carp averaging 37.8g and the fish were fed for 189 days. In the first pond where the feed with $20\%$f ish meal content ($19.0\%$ crude protein) was fed, the general common carp grew to 776.2g average (63 survived), colored common carp to 504.2g (24 survived), and total average to 701.1g (87 survived). In the second pond where $35\%$ fish meal feed ($27.3\\%$ crude protein) given, the fish grew to 792.9g (70 survived), 539.1g (23 survived) and 730.1g(93 survived), respectively, and in the third pond where $50\%$ fish meal feed ($34.6\%$ crude protein) given, the fish grew to 983.7g (49 survived), 630.4g (23 survived) and 870.8g (72 survived), respectively. A significant mortality during the experiment was due to an accidental introduction of Trichodina and Dactylogyrus infected with the stocked fish under experiment at the beginning. In this experiment the rate of harvest per hectare was very low being 1,352kg, 1,495kg and 1,447kg respectively which is tess than half of the yield at general commercial fish ponds. Therefore, it is concluded that at this rate of reduced production trial, the content of protein in the feed must not be cut down from the normal level.