20 U. S. BUREAU OF FISHERIES 
as a part of the determination of abundance of all species of ground- 
fish. 
At the Boston Fish Pier the captains of all vessels of over 50 gross 
tons are interviewed at the end of each trip. The data listed includes 
the day and hour of departure and arrival at the pier; the fishing loca- 
tions by rectangles covering 10 minutes of latitude and of longitude; 
the depth fished; the number of hours of fishing time lost through 
bad weather, engine trouble, or other causes; the proportion of time 
spent on each bank; and the proportion of the trip (and of most of 
the species caught) on each bank. For line-trawl vessels the number 
of tubs of gear set on each bank and in each depth also is obtained. 
These interviews are now being made by Mr. Bearse. During 1939 
the catches were allocated to their appropriate subarea and depth 
zone, and the fishing time for selected groups of otter-trawl vessels 
was calculated. ‘The calculated number of fishing days and catch 
allocations were added to the punch cards used by the Division of 
Fishery Industries in tabulating the material for its monthly bulle- 
tin on the landings at the three principal New England ports accord- 
ing to fishing bank and type of gear. As soon as the indices of 
abundance by species for the 1932-38 period are completed it will be 
possible to follow the changes in abundance from month to month. 
For the two selected groups of large otter trawlers, the catch and 
number of days of fishing in each statistical subarea during each 
month has been taubulated, according to depths fished, for the period 
1932-88, inclusive. One group of trawlers is slightly over 90 per- 
cent as efficient in fishing ability as the other group. By making an 
allowance in the number of fishing days, it is possible to place the 
two groups on an equal basis and to combine the data for final 
analysis. 
The determination of abundance is further complicated, however, 
by the necessity of analyzing the data according to the depths fished, 
inasmuch as different species vary in their choice of habitat. Accord- 
ingly, all catches have been allocated to 3 depth zones, namely: Shal- 
low, 0 to 30 fathoms; medium, 31 to 60 fathoms; and deep, over 60 
fathoms. 
The analysis of trips for area XXII—the banks of the Gulf of 
Maine, Georges Bank, and Nantucket Shoals—in which the otter 
trawlers fished wholly within 1 depth zone and 1 statistical subarea, 
show that although most species vary considerably in abundance in 
the different depth zones, this is not true for haddock. Giving each 
depth zone an equal weight, the relative abundance of large haddock 
on the basis of 100 percent was 35 for shallow water and 32 for both 
medium and deep water. Scrod haddock had a relative abundance 
of 37 for shallow, 40 for medium, and 23 for deep water. This may 
be an artifact, because, since haddock represent over 60 percent of the 
catch, the fishermen are seeking locations where they are most abund- 
ant and fish each depth most intensively at the time when haddock 
are most abundant. there. 
The flounder group—blackbacks, lemon sole, and yellowtail—defi- 
nitely prefer shallow water, and yielded percentages of 88, 72, and 
76, respectively, as compared to 11, 23, and 20 for medium depths, and 
only 1, 5, and 8 percent for deep water. Grey sole and dabs, on the 
other hand, are deep-water species; 84 and 69 percent coming from 
over 60 fathoms. Cusk, pollock, and hake are all taken in much 
