HATCHING EXPERIMENTS AND THE 
UTILIZATION OF “ WASTE OVA.” 
We have been trying for some years to find out how best to 
prevent the immense waste of ripe ova which occurs during the 
spawning season of the common fishes. Recognizing the difficulties 
attending dealing with it at sea in the trawlers, and obtaining a 
certain degree of success with isolated experiments made in previous 
years, we decided this year to put the problem to the test of a large 
series of experiments with ova and milt obtained from fish brought 
to North Shields market. The results are given in tabular form. 
SPECIES. 
Glh March. 
TIME DEAD (parent fish). 
RESULT. 
1. Haddock 
MALE. 
... 4 to 5 days ... 
FEMALE. 
4 to 5 days ... 
Failed to fertilize. 
1a. 
••• 9) ••• 
JJ ••• 
2- 
... 1 day 
>1 ••• 
1* 
2a. 
••• n ••• 
>1 ••• 
3. 
••• ••• 
1 day 
»> 
4. Cod 
... 4 to 5 days ... 
4 to 5 days ... 
»1 
(At this period (6th March) haddock and plaice were ripe, but 
cod, on the whole were just getting to the ripe condition. All these 
fish were preserved in ice). 
13 th March. 
5. Cod ... 3 to 4 days ... 3 to 4 days ... Failed to fertilize 
OA. ,, ,, ... ,, ... jf 
(While the trawled haddocks were altogether ripe, an entire 
batch of coble-caught haddocks were either immature or spawned). 
mu 
March. 
fi. Cod 
... 2 days 
• •• 
2 days 
... Failed to fertilize 
()A. ,, 
... 99 
... 
»» 
... 99 
19 th March. 
7, Haddock 
... 2 days 
... 
2 days 
... Failed to fertilize 
7 a. 
••• >1 
... 
n 
... ,9 
7 b. 
••• JJ 
... 
>» 
... 99 
20 th 
March. 
R. Plaice 
1 day or less 
1 day 
f 
Fertilized and developed to 
to the extent of 30 % of ej'gs 
8a. „ 
I) 
•• n 
taken. Embryo reached 
across yolk sac in 0 days. 
