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13. Preservation of the Crawfish. 



VVe have seen that the close season, which has been adopted 

 with a view to the protection of the Cape Crawfish, corres- 

 ponds to the months in which the males are in deep water 

 engaged in casting their shell and in a sickly condition. They 

 do not take the bait readily at this time and are unfit for 

 commercial purposes. The females are at this time in shallow 

 water, some still carrying their eggs, but most having got 

 rid of them. 



This is therefore the most favourable season for the fishermen 

 and the factories to suspend their operations, but it is doubtful 

 if the " protection " thus afforded by such a close season is 

 of any considerable value. The males cannot readily be got. 

 and are unfit for canning, so that fishing operations for the 

 factories would be confined to females, but the females which 

 have spawned in this season are just those which presumably 

 could best be spared and the catching of which would do the 

 least harm. As the females which have just given rise to pro- 

 geny are of less value economically than those about to do 

 so, the most effective close season would cover the months 

 just previous to the time at which they get rid of their eggs. 



However suitable this close season may be therefore for the 

 fishermen it cannot be held to be the most effective for pre- 

 venting overfishing and damage to the supply. 



A second means adopted for the preservation of the industry 

 was to impose a size limit of 3 inches (measured from the base 

 of the eyestalk to the end of the carapace or shield). It was 

 enacted that no crawfish below this size should be caught. 

 This however protected, it is to be noted, three different classes 

 of crawfish : first, the very small forms (males and females) 

 such as were of commercial use as a delicacy ; second, the 

 adolescent and sexually mature males ; and thirdly, the 

 adolescent and secondly mature females. We have adduced 

 reasons for believing that the first are particularly liable to 

 the attacks of such natural enemies as the octopus, and nature 

 has made special provision for a natural drain on these forms 

 by their large numbers so that the damage caused by man is 

 probably insignificant as compared with the normal mortahty 

 at this season. With regard to the second, the protection of 

 young adolescent males, these it would appear are just the 

 forms which can most readily be dispensed with, being the 

 least valuable from the point of view of the preservation of 

 the species. An analogous case is that of seals, where the 

 young males or " bachelors " are found to be those that 

 can be killed off with least damage to the industry. In both 



