YELLOW PERCH OF LAKE ERIE 



209 



Ontario waters. The average total production of 

 about 3/3 million pounds diu-ing the period 1885-99 

 appears high only when consideration is given the 

 low fishing intensity and the crude apparatus em- 

 ployed. The output of the fishery was low in 1903 

 but tended to increase, though h-reguJarly, during 

 the 1900-1920 period. The average annual yield 

 of 2,464,000 pounds during this period was approxi- 

 mately 70 percent of the earher average. The 

 following period, 1921-27, was the steadiest one of 

 the fishery, with but little fluctuation from an 

 average of 4,384,000 pounds. This average was 

 1.78 times the average of the preceding period and 

 about 1.29 times the 1885-99 average. The 

 period 1928-35 was one of tremendous annual 

 productions and violent fluctuations in yield from 

 year to year. In every year, the catch exceeded 

 the best of any previous period, and in 5 of the 8 

 years it was more than 10 million pounds. The 

 average annual catch of 12,116,000 pounds was 

 4.92 times the 1900-1920 average and 2.76 times 

 the 1921-27 average. Dm-ing 1936-47, production 

 fell off', with only one year, 1938, yielding as much 

 as the poorest of the preceding period. Wide 

 fluctuations in yield persisted into this last period. 

 They were caused largely by variations in the 

 catch in United States waters, and these in turn 

 were due to variations in Ohio's yield. The aver- 

 age catch of 4,050,000 pounds in 1936-47 was 

 only about a third of the 1928-35 average but was 

 approximately 1.25 times the average of the 

 earliest period, 1885-99. 



The grand average production of yellow perch m 

 all waters of Lake Erie for the years 1885 to 1947 

 was 4,964,000 pounds. 



The tendency toward an increasing variability 

 in the annual catch in United States waters 

 suggests the dependence of the commercial fishery 

 on a small number of age groups. This inter- 

 pretation is supported by the observation (p. 245) 

 that in the present-day fishery a year class is 

 normally of major importance for little longer than 

 a single year. Under such conditions it may be 

 expected that production would be sensitive to 

 variations in the strength of year classes and 

 hence subject to sudden and wide fluctuations. 



Any discussion of the factors that contributed 

 to the changes that have occurred in the produc- 

 tion of yellow perch in Lake Erie must be in 

 large measure speculative. Although certain 

 events are known to have contributed to the 



observed changes, their precise effects are diflScult 

 to evaluate. Brief mention may be made of the 

 more important factors. 



The early fishery in Lake Erie was conducted 

 primarUy on the inshore grounds with relatively 

 crude gear. As production on these grounds 

 declined, larger, faster, and seaworthier boats 

 were buOt which permitted not only the extension 

 of operations to more distant grounds but also the 

 handling of more nets. The number of boats in 

 operation also increased rapidly with expansion of 

 the fishing grounds. Further increase in the 

 amount of gear handled by each boat foUowed 

 introduction of the power lifter for gill nets in 

 the 1890's and for trap nets in the early 1930's. 

 Efficiency of the nets was increased by reducing 

 the size of the meshes, by using finer thread in 

 gill nets, and by "reefing" or tying down the 

 gill nets. Gill nets were made still more eflficient 

 by the development of the buU net, a gill net 100 

 meshes deep, fished in all strata of water from top 

 to bottom. The shift from pound nets to trap 

 nets and more recently a partial shift from gUI 

 nets to trap nets also increased exploitation, since 

 trap nets are the most efficient gear now in use. 



Although it is not possible to state precisely 

 the extent to which fishing intensity has increased, 

 it is valid to state that the increases in the amount 

 and efficiency of gear just mentioned have led 

 to a multiplication of fishuig intensity in recent 

 years over that of the early fishery. 



For many years the practice has been to decrease 

 gradually the size of mesh in the nets to com- 

 pensate for diminishing yields. It was not until 

 1937 that the State of Ohio reversed the trend 

 by increasing the size of mesh in trap nets to 

 afford greater protection to the smaller fish. 



In addition to these developments that have 

 affected the fishery as a whole, there have been 

 other cu'cumstances that contributed more speci- 

 fically to an increase in the intensity of the fishery 

 for perch. The collapse of the cisco fishery, for- 

 merly the most productive in Lake Erie, in 1925 

 forced many operators, particularly the gill-netters, 

 to turn to other species. The resultmg increase 

 in intensity of the fishing for perch was an impor- 

 tant factor in the rise in production of this species. 

 The yield of perch was affected also by the reduc- 

 tion in July 1929 of the minimum legal size from 

 9 to 8/2 inches in the State of Ohio. The record 

 catch of 13 million pounds in' Ohio in 19.34 oc- 



