36 



MARINE AND FISHERIES 



1-2 EDWARD VII., A. 1902 



From these pens I cleaned out the clams, whelks, smaller stones, &c., levelled down the 

 dirt, and pressed it somewhat solid. Upon the surface I then placed a known number 

 of good healthy clams taken from the same district, and kept watch every tide or two 

 as to what progress they made in re-burying themselves in the ground. Some proceeded 

 to burrow while others appeared satisfied to remain on the surface several days. In a 

 few days most of them had made some headway but either from disinclination or 

 inability their progress was very slow, requiring about two weeks to become covered or 

 nearly so. I concluded that if they were left on the surface of hard clay or gravelly 

 soil at some distance above low water mark they would be almost sure to die from 

 exposure to the sun, not to speak of their risk of being captured by some enemy. The 

 surface of ground that has been dug over for clams always shows numerous bleached 

 shells many of which must have originated in the way described. The statement some- 

 times made by clam fishers, that the ground dug over one year is just as well supplied 

 with clams the following year, can hardly be credited, if we consider a district from 

 which they have been systematically extracted. In most places with which I am 

 acquainted this is not done. The clammers dig here and there, wherever they can do 

 the best, leaving intermediate patchrs undisturbed, which may be the ones searched 

 next season. Some people seem to think that digging and loosening of the soil proves 

 beneficial to the clams. This is generally a mistake. However valuable such procedure 

 may be in the cultivation of potatoes it is a positive danger to clams. The loosened 

 soil is in many places swept away by the tide, leaving a hard bed and loose stones. In 

 very quiet, retired places where the bottom is mud such disturbance has less serious 

 effects. Although the larval claai is free-swimming and the young clam is able to creep 

 about with considerable speed and to burrow rapidly, when once it has found a spot to 

 its liking and has become buried in the soil it ceases for ever to rove about. By the 

 time it has grown to maturity its body is too unwieldy to admit of anything like satis- 

 factory locomotion by means of its small foot. Its natural condition then is to live a 

 sedentary life, protected within a more or less deep burrow, and any interference with 

 this habit is a disadvantage against which it has to contend. The ability of the young clam 

 to accommodate itself in mud, sand, gravel, clay, even rocky places, in protected coves, 

 or in exposed banks, is an indication of the success with which it might be trans- 

 planted, even at long distances from its original home. As a proof of this we might 

 mention the introduction of Mya arenaria into San Francisco Bay. Upon the completion 

 of the transcontinental railroad, about 1869-70, some oyster dealers in San Francisco 

 began to import small oysters by the car-load from the Atlantic and to plant them in 

 San Francisco Bay, where in a year or two they grew to good marketable size. It was 

 with these importations that the young of Mya arenaria were accidently introduced to 

 the Pacific. It was first observed in San Francisco Bay in 1874 by Dr. Hemphill. He 

 gave some rather small specimens to Dr. Newcomb for examination, who regarded them 

 as a new species and named them Mya hemphillii. That it is a late introduction into 

 those parts is also proved by the fact that mounds and shell-heaps on the shores of that 

 bay fail to reveal any trace of the shells of Mya, although those of Tapes, Macoma, 

 Mytihis, Cardium, &c., occur. These native clams are now almost superseded in abun- 

 dance and good quality by Mya arenaria. 



REFERENCE TO THE UNITED STATES AND GREAT BRITAIN. 



The clam fisheries of the United States have b-^en referred to in the foregoing 

 pages. It will, perhaps, not be out of place here to say a few words about their 

 equivalent in Great Britain. There the mussel (Mytilus edulis) is employed for the 

 same purposes for which we on this continent use the clam. It is impossible to get a 

 correct estimate of the amount used, since the figures given in the reports generally 

 include the mussel among ' other shell fish.' On the coasts of Yorkshire and Durham 

 they are employed as bait by a few hundred fishermen, but through decline of the 

 mussel beds these men are sometimes forced to seek supplies from the continent, 

 although formerly they were able to send mussels in quantities to the local markets and 



