A new method for treating plaice (Pleuronectes platessa L.) gonads in order to facilitate the estimation of the egg production
van Leeuwen, P.I. (1972). A new method for treating plaice (Pleuronectes platessa L.) gonads in order to facilitate the estimation of the egg production. Aquaculture 1(1): 135
In: Aquaculture. Elsevier: Amsterdam; London; New York; Oxford; Tokyo. ISSN 0044-8486; e-ISSN 1873-5622, more
|  |
| Abstract |
In fecundity studies it is important to estimate the number of eggs produced. The methods applied up till now were rather time consuming. This was mainly caused by the fact that the eggs had to be immersed for similar to 4 months in Gilson's fluid. A method is described below by which it was possible to reduce this time to 1 week. The experiments were mainly carried out with plaice (Pleuronectes platessa). The gonads are first boiled in fresh water for similar to 5 minutes, after which the eggs are freed from the covering membranes. Then the eggs are put into water and boiled again for 2 minutes and careful stirring separates the eggs. After decanting almost all the water, the remaining membranes and connecting tissues are removed. The eggs are not spread out in petri-dishes and dried at 70°C for 48 hours. To prevent lumping it is advisable to divide the eggs in small quantities over several dishes. To speed up the drying process some alcohol may be added to the eggs. The advantages of this method are apparent as the eggs can be counted as early as 1 week after sampling the gonads. In addition, the method is safe because it does not make use of the highly poisonous, mercury-containing Gilson's fluid. By leading the eggs along the photo-electric cell of a Decca agg-counter it was shown that the eggs treated with the above method retained their round shape better and that less eggs were broken than with the old method. |
|
