18 man's influence on shell-fishes. 



mussel-bed, for instance, has a marked influence on the abund- 

 ance of the pelagic larval mussels, just as the vicinity of a bed 

 of oysters or of clams produces similar effects. In fine 

 weather many of these moUuscan larvae, rising from the 

 bottom, sport at the surface, while by-and-by as they get 

 older they leave the upper regions of the water to descend 

 either to bore in the sand or other medium or take up their 

 habitat on the bottom. The fishes thus, as in the case of the 

 crustaceans, have a double opportunity — first on their rising 

 and again on their descent. The pelagic mollusks, from their 

 enormous numbers and wide distribution, would alone support 

 a great oceanic fauna of predatory animals, and, as they live 

 on microscopic plants and similar minute food, they likewise 

 illustrate the close connection between the two kingdoms. 

 Moreover as food for young fishes they not only give abundance, 

 but afford the necessary variety in dietary. 



For ages man has gathered the sedentary and creeping 

 shell-fishes, such as mussels, cockles, and whelks, for food and 

 bait, often without the slightest restriction, as in the case of the 

 whelk and limpet, yet extinction has not ensued, not even in 

 the much abused mussel, which has suffered on the one hand 

 from reckless fishing and on the other from the very varied sup- 

 positions of fishermen, mussel-merchants, and politicians. Some 

 years ago an agitation was raised about mussels. Pamphlets and 

 the newspapers of the day kept attention directed to the urgent 

 need for mussel-reform in view of the decrease of the supply. 

 A Committee under Lord Tweedmouth (then Mr Marjoribanks) 

 was appointed by Parliament to investigate the subject. The 

 committee made important recommendations, giving the Fishery 

 Board powers to regulate the various mussel-beds and prevent 

 waste. Very little change, however, has ensued in regard to the 

 distribution or increase of the mussel, and it may be supposed 

 that the agitation in some cases was not disinterested. At any 

 rate, the supply of mussels at this moment is sufficient. The 

 most elementary administration and the bed-system enable this 

 species to maintain its ground. That a populous centre should 

 send companies of cockle-gatherers almost daily to a sandy 

 flat and this for hundreds of years — without exhausting the 



