OYSTER-CULTURAL PROBLEMS OF CONNECTICUT. 3 



From the fertilized egg the oyster develops rapidly into a swim- 

 ming embryo containing its own nourishing material, and from that, 

 within a day or so, depending upon the temperature, it develops into 

 another, more vigorously swimming stage — the microscopic, actively 

 feeding larva with a double or two-valve shell somewhat like that 

 of a clam. This stage continues much longer than the previous one. 



Although the larva's habit of occasionally settling to the bottom 

 tends, to a limited degree, to check the influence of the tide, during 

 these early stages the oyster is practically at its mercy. Aside from 

 this settling habit only the back-and-forth or reciprocal action of the 

 tide and whatever collecting or stationary effect it may produce by 

 means of eddies prevent the larvae from being carried hopelessly 

 about and broadcasted, as it were, in the most wasteful and destructive 

 manner. Finall}', a very small proportion of the oysters complete 

 the larval stage, "set" by attachment to firm, hard objects such as 

 oyster shells, and attain the spat or first sessile stage. 



Experience and the science known as ecolog;v^ teach us that for any 

 proper understanding of the life of any organism — plant or animal — 

 we must study it in relation to its environment — ^organic and inor- 

 ganic, dynamic and passive. The environment of the oyster, ob- 

 viously, is an aquatic one, but not all aquatic environments are 

 suitable for it. Fresh-water areas are, of course, ruled out, and so 

 are those of full ocean saltness. Between these two extremes are 

 the moderately salty or brackish areas. It is in such areas, which 

 embrace so many sounds, bays, harbors, and estuaries of all sorts, 

 that the oyster finds its proper environment : but here, again, qualifi- 

 cations must be made. Food organisms must be sufficiently plentiful, 

 enemies not too abundant, the bottom neither too soft nor too shift- 

 ing, the chemical content of the water such that no serious poisonous 

 effect will be produced, and the water temperatures those to which 

 the oyster may easily adapt itself. 



That both salinity and temperature are important factors in 

 Long Island Sound oyster cultivation is apparent from consideration 

 of the situation. The Sound is almost the northern range limit 

 of the oyster along the Atlantic coast of the United States. Being 

 a very large body of water with a tremendous tidal flow from the 

 ocean, its salinity is reduced comparatively little by the generally 

 small if rather numerous rivers that flow into it. It therefore ap- 

 proaches the range limit both as to salinity and temperature. Al- 

 though the salinity of the Sound is rather high for the develop- 

 ment of oysters of the very best " meat," it by no means shows an 

 unfavorable effect on reproduction. Summer temperatures, however, 

 have a rery important bearing in this regard. 



It has long been known that water temperature is an important 

 factor in' oyster spawning, a fact which the work of the bureau's 

 investigators has served to emphasize. This does not mean that any 

 hard and fast rule can be laid down for the relationship between 

 water temperature and spawning, nor does it follow that temperature 

 is the only influence involved, Ijut it is an observed fact that oyster 

 spawning can be held back by low temperature and induced or 

 " forced " by an increase in water temperature. Under natural con- 

 ditions the really vigorous and extensive spawnings almost, if not 

 quite always, are coincident with a marked rise in temperature. 



