[15] EGGS OF THE PLAICE, FLOUNDER, AND COD. 441 



Plaice 36 centimeters long, weight, 457 grams: ovary, 132.5 grams; 

 number of eggs, 80,940. 



Plaice 31 centimeters long, weight, 374 grams: ovary, 113.4 grams; 

 number of eggs, 111,300. 



Cod* 30 centimeters long weight, 525 grams: ovary, 141 grams; 

 number of eggs, 305,900. 



The smallest mature plaice which has come under my observation 

 was 25.5 centimeters long, and weighed 142 grams without the ovary, 

 which weighed 57 grams. It is, for the present, not very important to 

 know exactly the average quantity of eggs of plaice. Not to make too 

 high an estimate, I assume that a female jjlaice lays, on an average, 

 75,000, and codfish, per pound, 200,000 eggs. I furthermore assume 

 that half of the fish caught are females, although passing through a 

 fish market one gets the impression that there are more female than 

 male plaice.t 



Using these estimates in my calculations I obtained the following 

 result: Near Eckernforde there were caught during a period of 9 years 

 1,706,848 plaice. Assuming that half of that number were females, we 

 get 853,000 multiplied by 75,000=73,985,000,000 plaice eggs (228 cubic 

 meters, or 231,348 kilograms). The quantity of cod caught was 354,162 

 pounds; assuming half of that quantity to have been females, we get 

 117,000 multiplied by 200,000=23,400,000,000 codfish eggs. The spawn- 

 ing season of both these kinds of fish lasts about two months, and it 

 takes the young fish about fifteen days to be hatched. It is, therefore, 

 probable that in the middle of the spawning season there is, on an aver- 

 age, at least one-fourth of that number of eggs in the fishing area at one 

 and the same time. The calculation, therefore, shows that within the 

 fishing area there must be at least 15,996,000,000 plaice eggs, and 

 5,850,000,000 codfish eggs. 



The reliability of this calculation depends on the correctness of the 

 statistics and a sufficient number of egg-counts. It is certain that we 

 have not yet reached a suflBciently large number of the latter, but there 

 is nothing to hinder more extensive counts. For the present, it is im- 

 material whether the figures obtained should be doubled or halved; for 

 all we aim at is to get an approximate idea of the real condition of this 

 matter. The objection might also be made, that of the total number of 

 fish caught during the year, a portion is taken from the sea in a mature 

 condition, and should, therefore, be subtracted. As regards my simple 

 question, "Is the number of spawning fish as large, or larger, than the 

 number of fish caught per annum ?" the circumstance referred to is of no 

 great weight, for the number of fish caught per annum is nothing but a 

 number from which this question may conveniently be started, if you 



* A Platesaa limanda weighing 642^ grams contained 807,467 eggs. 



t The same applies to the codfish ; but Earll found among 13,300 codfish 67 per cent, 

 males. According to Mobius (paper read at the general meeting of the Schleswig- 

 Holstein Fishery Association, March 1, 1883), a plaice weighing 450 grams contained 

 *281,380 eggs. He counted 120,000 eggs per plaice, and two to three females to one 

 euale. 



