FISHERY PROBLEMS 179 



and in the early spring the Arcachon fishermen often 

 take in the same bank specimens of various sizes whose 

 genital organs are unequally developed. The second 

 fact : sardines often shelter a parasite, and the majority 

 of those thus infested are sterile ; nevertheless they 

 mingle with healthy individuals and approach the coast 

 in the same bank. The third fact : the herring which 

 come to the surface and enter the bays to spawn are 

 not all full of ova. In the neighbourhood of the 

 Shetlands a good fifth of them are sterile ; nevertheless 

 these sterile individuals join the others in the same 

 shoal and follow them. Now, the shoals of herring 

 migrate only in order to spawn, and to find after 

 spawning a copious supply of food. Consequently 

 those fish which are unable to spawn should not be 

 found with the shoal. Nevertheless they do form part 

 of it. We can only explain their action as the result 

 of imitation, a psychological and social factor. The 

 simplest observation will reveal the existence of veritable 

 societies, founded upon a community of requirements, 

 of bream, sar, and gilt-heads. Finally, I must not fail 

 to mention the paternal instinct of the Coitus scorpius, 

 which carefully watches the eggs when laid, and of the 

 blennies, which, according to M. Guitel, actually solicit 

 the gravid females and invite them to deposit their eggs 

 beside those which they are already guarding. 



As we see, to resist the hostile ocean and its enemies, in 

 short, to eat and perpetuate its species, the fish is forced 

 to employ all manner of ruses. It cheats its environ- 

 ment and it " bilks " its fellows. The essential matter is 

 to find a place in nature. That place once conquered, 

 the species accommodates itself to nature as best it can, 

 and in the absence of some sudden catastrophe it no 

 longer changes and remains always faithful to the 



