DETERIORATION OF AMERICAN OYSTER-BEDS. 35 



together with all oysters unfit for market, thrown back into the water. 

 The limits of the dredging-grounds are not accurately defined, and 

 the vessels frequently drag large numbers of shells and oysters some 

 distance beyond the boundary of the beds. The dredge, especially 

 when full, acts as a scrape, and carries before it much that would be 

 collected in the network attached to it, had that receptacle been open. 

 After " culling " the oysters, or separating them from the old shells, 

 those shells are thrown back again and with them many young oysters. 

 Should they fall on suitable ground, and any which is sufficiently con- 

 sistent to support them is suitable, they form a small colony which, by 

 action of natural causes, or the dredges, soon becomes attached to the 

 main bed and the area of the latter is thus enlarged. The exposure 

 of suitable " cultch " on bottoms contiguous to the bed is effected by 

 the dredges in the above manner, and they are thus mainly instru- 

 mental in extending the area, especially by their direct action in raking 

 down the bed and spreading the shells and oysters. Will the dredg- 

 ing also account for the diminution of the oysters ? 



Without, for the present, going into the question of propagation, 

 which will be subsequently discussed, it may be stated here that both 

 male and female of the American variety of oyster expel the genera- 

 tive matter into the water, where the eggs must meet the male fluid in 

 order to be fertilized. That being the case, it is evident that the more 

 compact the bed, the more closely settled the community of oysters, 

 the greater the chance the ova and spermatozoa have of coming in 

 contact ; or the chance of fertilization of the eggs is inversely propor- 

 tional to the distance separating the oysters. Hence, should the ma- 

 ture, spawn-bearing oysters on any bed become very much diminished 

 in number or widely separated from each other, there would be but a 

 slight chance of contact of ova and spermatozoa, and a consequent 

 failure of reproduction. Should the bed be so situated that the cur- 

 rents passing over it did not also pass over other more plentifully 

 stocked beds, it would receive no outside support, and the mutual 

 assistance generally rendered would not be obtained. This is the case 

 with one of the largest beds in Pocomoke Sound, and, as would be in- 

 ferred, the most extensive deterioration was noticed on that bed. 



The removal of mature brood-oysters would, then, cause a dimin- 

 ished fecundity, and, should this removal continue, the fecundity will 

 naturally diminish, until there is virtually no reproduction on the bed. 

 But the removal of brood-oysters is not the sum total, by any means, 

 of the effects of the dredging. Millions of young oysters, unfit for 

 market, are carried off sticking to the shells of the mature oysters, 

 and with those shells find a final resting-place on the shell-heaps of the 

 packing-houses. Nearly as many young are desti*oyed by being thrown 

 from the dredging-vessels upon soft or unfavorable bottoms, no care 

 being exercised, in the hurry and press of work, to see that the young 

 are returned to the beds or other suitable ground. 



