PROGRESS IN BIOLOGICAL INQUIRIES, 1939 19 
provides a perspective for analyzing the state of a fishery. The catch, 
tabulated according to vessel and size and type of gear, is being 
compiled from the reports of landings at the three principal New 
England ports. Data have been assembled for all except 2 years of 
the 1927-89 period. 
A comparison has been made between the catches of 1927 and 1938. 
During 1927 the average number of vessels that landed each month 
was 218 (including a total of 364 boats). The average was computed 
on a 12-month basis so that in the purse-seine fishery, for example, 
if 60 boats fished 6 months the average for the entire year would 
be 30 boats. If a boat used two types of gear during the same month, 
each gear has been credited with half a month. The average number 
of boats that landed catches each month during 1938 was exactly the 
same, 218 (332 different boats landed). Not only was the same num- 
ber of landings made in 1927 and 1938, but the average gross tonnage 
per individual boat was 96 in each year. 
However, there was a 50 percent increase in the landings of all 
species, from 268,000,000 pounds in 1927 to 401,000,000 pounds in 
1938. This appears to have been due largely to a radical change in 
the proportions of each type of gear used. All forms of gear except 
otter trawls and sink gill nets decreased in numbers. Hand-lining 
accounted for an average of 10 boats fishing throughout 1927, but that 
method of fishing had practically disappeared in 1938. ‘The average 
number of purse seiners decreased from 35 to 20. The line trawlers 
decreased 34 percent in number and 52 percent in gross tonnage. This 
apparent discrepancy is accounted for by a decrease from 49 to 23 
in the line trawlers of over 50 gross tons, but an increase from 8 to 
15 in the average number of smaller line trawlers. The number of 
otter trawlers increased 60 percent, from 76 to 121, due largely to the 
building of new boats, although, to a lesser extent, it was also due to 
the present practice of operating a boat throughout the year. In 
addition, several line trawlers were converted for otter trawling. The 
medium-sized otter trawlers in operation, 51 to 150 gross tons, in- 
creased from 22 to 34, or 55 percent; the large, from 24 to 40, or 67 
percent; and the small otter trawlers from 30 to 47, or 57 percent. 
Thus, the large trawlers showed the greatest increase in numbers. 
In 1927, with an average of 24 large trawlers in operation, 88 percent 
were propelled by steam. In 1938 steam accounted for only 24 per- 
cent of an average of 40 large trawlers, the balance being Diesel- 
powered. 
Other factors in addition to the shifts in type of gear contributed 
to the 50 percent increase in landings. One was the adoption by the 
otter trawlers of the Vigneron-Dahl trawl, which increased their 
catches considerably. A second factor is the newly developed fishery 
for rosefish, which produces a greater poundage per unit of effort 
than any other species. 
Population estimates —Having laid the ground work for the de- 
termination of total catch by season and area, and of total fishing 
effort, there remains the third variable—abundance. 
Very fortunately the haddock investigations, as one phase of their 
activity, commenced collecting data at the Boston Fish Pier in 19382 
that are of great value to the groundfish analysis. The phase of the 
haddock work dealing with abundance will henceforth be carried on 

