to learn two things from the distribution of these fry. First, at what date were the eggs spawned out of the mother oysters, and how fast do they grow, so we may predict when they will be ready to set as spat. Second, how do these fry behave in respect to the tidal currents, so they will not be lost by being carried to sea, and at the same time succeed in effecting their own distribution. The first question is relatively easy to solve, and we have made good progress in its solution, but the second is still quite obscure If we could always have calm weather, this point would be quickly determined, but unfortunately we rarely have such weather. The fry make special responses to the state of agitation of the waves, to the amount of sunshine, to temperature, etc., but these by themselves would not be so bad. The trouble is that the agitation of the water stirs up mud which we do not know how to separate from the fry, and so it interferes with the determination of their number. Very possibly the same agitation that raises the mud raises the fry also, when they would rather stay at the bottom.

On counting the fry in the water from day to day, we find great variations in the numbers. Do these fluctuations represent an actual fact in the behavior of the fry, or are we dealing with totally different lots of fry, produced at different places, and carried successively by currents to the points where we see them? We believe that both these things are true. The difficulty arises in determining how much to attribute to each factor. If the latter should be preponderately true, then our findings cannot so easily be compared with one another, as when we are dealing with the same lot of fry all the time.

Under these circumstances, the best that can be done is to select the highest number of fry found each day and analyze it into its component broods, which may be as many as three or four, according to the number of warm waves that have stimulated the spawning activities of the oysters. Then we determine the rate of growth of each brood, keeping tab on the largest brood. This is likely to produce the principle "set" of spat, upon a date that can be predicted with tolerable accuracy, although the exact effect of temperature in hastening the growth of the fry has still to be established; only an approximate knowledge of this is as yet available. In the cold Canadian waters, Dr. Stafford has determined the free swimming period to be four weeks. In our waters early in the season we found it to be three weeks. Some of the broods in waters that reach or exceed 80 degrees in warmth, undoubtedly mature in less than two weeks and it looks possible that the period may in southern waters be as short as a week.

At Barnegat we found fry already in the water, with both a brood of small and one of medium size, by the middle of June. The hot wave of the 25th, not only set free a new brood of fry whose presence became evident on the 30th, but caused the large survivors of the previous broods to "set." By consulting the Chart Plate I we find that there was also manifested a large brood of medium fry on the 30th, which might possibly be the same as the brood of small fry seen on the 26th, as the water

was extra warm at this time. Quite a small number of large fry was found throughout July; but larvæ of smaller size disappeared gradually during a period when the water became decidedly colder. On July 18th a warm wave brought into view two broods of limited numbers, one small and one of medium size; and during the succeeding warm days large fry were present and "setting" as spat. No further broods of fry appeared after the close of July. For purposes of corroboration we must bear these facts in mind when we later in this report consider the spawning and spatting observations.

Now let us turn to our data secured at Edge Cove. Here we found few fry until the 19th of July, when there were small, medium and a few large fry present. From this time on to the third of August, during a warm spell, we found increasing numbers of small fry in the water, but fewer medium ones, and very few large ones, indicating a great mortality of these earlier broods. Later in August, beginning the 19th, in the midst of another warm period, we again have a modest showing of fry, in all three sizes, which continues with gradual decrease into September.

The number of fry at the most favorable showing did not equal more than half that found in other years, and they were distributed throughout the season more generally, being spread "thin" as it were. There also is good evidence of a greater mortality among them than usual. Comparing Barnegat and Tuckerton, we find that oyster propagation was later in the latter region than in the former. As the water was warmer at Tuckerton than at Barnegat, this seems anomalous. Further discussion of these matters is deferred to later sections of this report. The proportion of clam fry was, as usual, greater at Tuckerton than at Barnegat.

Table II-Plankton Data Pertaining to Oyster Propagation, Barnegat, 1914. (Continued)

Table II-Plankton Data Pertaining to Oyster Propagation, Barnegat, 1914.

S. str. cloudy, few urns, copepods.

July 2... 8 a. m.

July 4... 7:30 a. m.

July 8... 2 p. m.

July 8...

Shad Pt.

July 8..

C.

16-75

3

July 9... 6:30 a. m.

6 flow.

A.

15-72

3

Copepods.

July 9..

B.

15-72

2

Copepods.

July 9..

16-71

6

6

July 10..

Noon.

10.

Few, net.

Copepods.

July 10.

6 a. m.

6 flow.

14-72

Snails.

July 10..

15-72

4

4

Snails.

July 10.

15-72

3

Snails.

July 11..

7:50 a. m.

7 flow.

16-72

2 b.

1,

Snails.

July 11..

16-72

Snails.