DESTRUCTION OF IMMATURE FISH 275 



But it generally happens that a fish becomes 

 large enough to be marketable before it has 

 attained sexual maturity. Codling, which are 

 only young cod, are large enough to be sold for 

 food when they are only about 10 inches long, and 

 plaice of 8 to 10 inches in length may very 

 easily command a ready market. Certain trade 

 standards become established in different places, 

 and fish may be classified with reference to these 

 rather than to their biological conditions. In the 

 language of the markets, fish may be " large," 

 "medium" or "sizeable," and "small," command- 

 ing, in each case, different prices, and those which 

 are too small to obtain ready sale may be called 

 " undersized " or " immature." Then if legal 

 standards of size exist, as in the cases of the 

 mussel, cockle, or oyster among shell-fish, or are 

 proposed in restrictive legislation, all fish below 

 these legal minimum sizes may again be termed 

 " undersized " or " immature." Thus, if the Bill 

 of 1900, which proposed limits of 10 inches for 

 turbot and brill, and 8 inches for plaice and soles, 

 had become law, all fish of the kinds mentioned 

 under those sizes would have been called 

 " immature," and the popular significance of the 

 term would have related to the legal, rather 

 than to the biological, standard. Marketable and 

 biological size-limits may, but generally do not, 

 coincide. Cockles, mussels, and oysters, for 

 instance, become sexually mature at sizes lower 



