432 BULLETIN OF THE BUREAU OF FISHERIES 



In studying the tides and currents several devices were used. At Station 2 

 an automatic tide gauge was put in operation, whereby a continuous record of the 

 rise and fall of tide in Milford Harbor was obtained. The velocity and direction 

 of the tidal currents at various depths and stages of the tide were determined by 

 means of Ecknian and Price current meters. In order to determine the drift or 

 general movement of the water along the Connecticut shore of Long Island Sound, 

 500 drift bottles with drags were released from several localities, and of these, over 

 300 have been recovered. 



The most important procedure was the collecting and examining of plankton 

 collections to determine the presence of oyster larvae. The method employed was 

 essentially the same as that used by Churchill and Outsell (1920; unpublished manu- 

 script, United States Bureau of Fisheries) for determining the abundance of oyster 

 larvse. The results obtained by this method are quantitative and of much greater 

 value than those obtained by drawing a tow net through the water. 



At each station, 50-gallon samples were taken at the surface and bottom and 

 occasionally at various depths. By means of a rotary bronze pump with 50 feet of 

 rubber hose weighted at the intake end a definite quantity of v/ater was pumped on 

 deck and strained through a net of No. 20 bolting silk. The plankton collected 

 was washed down into a quart jar, labeled, and preserved in 10 per cent formalin. 

 In the laborator}-, the contents of each jar was washed through a series of sieves 

 covered with Monel-metal wire of Nos. 80, 100, 150, 200, and 270 mesh. This 

 procedure served to classify the oyster larvae according to their size and greatly 

 simplified microscopic examination of the samples by dividing them into several 

 portions. The plankton collected in each sieve was washed into watch glasses, and 

 the number of oyster larvae was determined by direct count under the microscope. 



The setting of the oyster larvae was studied in 1925, 1926, and 1927 by arrang- 

 ing several types of stationary and floating spat collectors in various positions, 

 according to the depth of water, tides, and currents. For spat collectors, brush, 

 glazed tiles, tar paper, clam, scallop shells, and oyster shells were used, the latter 

 being set out in lath crates and wire baskets. 



TOPOGRAPHY 



Milford Harbor is situated on the Connecticut shore of Long Island Sound and 

 lies about halfway between two great oyster-producing centers — Bridgeport and 

 New Haven. The general topographic and hydrographic features of the harbor and 

 surrounding territory are shown in Figure 1. In this discussion, the term "Milford 

 Harbor" is applied only to the area above the stone breakwater at Burns Point, 

 which, on the hydrographic charts, is labeled "Wepawaug River." This small 

 body of water covers approximately 80 acres, about half of which is exposed at low 

 tide. It is a small but typical oyster-producing harbor, and in former times the 

 entire area was a natural bed of oysters. In this nearly inclosed basin, the brackish 

 water of Long Island Sound mixes with the fresh water from two small streams — 

 the Wepawaug and Indian Rivers — producing ideal conditions for oyster growth 

 and propagation. 



As a result of overfishing, the harbor was found to be virtually devoid of oysters, 

 so that it was necessary to restock it before carrying on the experiments. The 



