56 



the animal, and the oysters were, therefore, separated into four classes, according to size, in the 

 following manner: 



The first class contained all those over three inches in length, and embraced all full-grown, 

 mature oysters. 



The second class contained oysters between 2 and 3 inches in length, and these were supposed 

 to be mature and fit for market, and between two and three years of age. 



The third class contained oysters between three-quarters of an inch and 2 inches long, and 

 represented the young growth of the preceding seasons, being thus oysters from six months to two 

 years of age. 



The fourth class contained all oysters under three-quarters of an inch in length, embracing the 

 most minute that could be recognized, and represented the young growth of the last spawning 

 season, or those of less than a year's growth. 



By obtaining a sufficient number of each class from each bed it was intended to establish 

 ratios between each class, which, compared with ratios on new and comparatively unworked beds, 

 would show whether the particular locality under examination was in a state of greatest productive- 

 ness or not, and by comparing the ratios of successive seasons, the increase or decrease, constant 

 or otherwise, could be ascertained, and the yield of the bed in ensuing seasons predicted. 



In order to have another and more correct standard for comparison and to arrive at certain 

 conclusions as to whether the spatting in any season was general and extending to all beds, or 

 confined to particular localities, and in order to know accurately the number of oysters surviving 

 each period of their perceptive existeuce, numbers of spat collectors were deposited upon the 

 different beds. It was the intention to frequently inspect these tiles, and by counting the number 

 of oysters on eacli tile at each examination the number of oysters surviving would be ascertained 

 and the age of the previously-established classes would be decided. Thus the life of a community 

 of oysters, free from the dredging influence and protected from all but natural enemies, would be 

 before us from the time of the first attachment until they reached maturity. 



The study of their embryo life properly belongs to the zoological student, and the method of 

 propagation and the successive stages of that life must be left to him to determine. It is valuable 

 to the inquiry under consideration, but not essential; as it is evident that we may neglect the 

 early stages of life and yet arrive at correct conclusions as to the number of mature oysters neces- 

 sary to support the beds in their best condition. 



Next in importance to the knowledge of the absolute fecundity of the bed is a knowledge of 

 those conditions which would influence it, and in order that no cause for the deterioration should 

 be neglected, and that all information bearing in any way upon the propagation and growth of the 

 oyster might be collected, several matters of secondary importance have been subjected to investi- 

 gation and the results embodied in either this or my previous report. 



Included under this head are — 



Investigations into the temperatures and the influence of increased or diminished temperature 

 upon the mature oyster and embryo. 



Investigations into the character of the water, especially as regards its increased or dimin- 

 ished density. 



Investigations into the character of the bottom and its influence upon the oyster. 



A determination of the direction and velocity of the currents and such collection of statistics 

 of the oyster trade and fishery as would show its present condition and give a value to the dredg- 

 ing factor; and, lastly: 



A collection and study of the fauna of the beds, particularly of those animals supposed to 

 affect the oyster. 



An attempt has also been made to collect the experience of the oystermen and dealers as to 

 the habits of the oysters, and as to the effect of the various changes of environment. 



Having shown what, in my opinion, were the objects to be obtained and the direction which 

 the investigation should pursue, it remains now to describe in detail the work of the party in each 

 branch of the inquiry and to decide upon the value of the results. 



