important differences in growth but a 

 progressive increase from south to 

 north in average age. Includes data on 

 such questions as causes of discrep- 

 ancies between calculated growth of dif- 

 ferent age groups, length of growing 

 season, growth compensation, length- 

 weight relation and condition (including 

 seasonal fluctuations and regional dif- 

 ferences), and sex ratio. 



DEASON, HILARY J., vide: RALPH HILE; 

 JOHN VAN OOSTEN. 



DRYER, WILLIAM R. 



1963. Age and growth of the whitefish in 

 Lake Superior. U.S. Fish Wildl. Serv., 

 Fish. Bull. 63:77-95. 



Data on size, age and year-class com- 

 position, growth, and length-weight re- 

 lation of whitefish from Bayfield, Wis., 

 and Marquette, Whitefish Point, and 

 Dollar Settlement, Mich. Growth rates, 

 from fastest to slowest, were: Whitefish 

 Point; Dollar Settlement and Marquette 

 (the two reversed ranks after 3 years); 

 Bayfield. The legal length of 17 inches 

 was reached as early as the fourth year 

 of life (Whitefish Point) and as late as 

 the seventh (Bayfield). Differences of 

 growth were largely established during 

 the first 5 years of life. The body- scale 

 ratio remained constant with increase of 

 fish length. Weight increased as the 

 3.2408 power of length. Age and year- 

 class connposition fluctuated at the same 

 port and differed among ports. The evi- 

 dence suggests existence of a number of 

 segregated stocks. At Bayfield, 51.5 

 percent of the fish were males, but 

 males were scarce among fish older 

 than the VIII group. All fish from Bay- 

 field shorter than 14.5 inches were 

 immature, and all longer than 17.4 

 inches were mature. The youngest 

 mature fish belonged to age-group IV, 

 and the oldest innmature fish to age- 

 group VII. 



DRYER. WILLIAM R. 



1964. Movements, growth, and rate of re- 

 capture of whitefish tagged in the Apostle 

 Islands area of LakeSuperior. U.S. Fish 

 Wildl. Serv., Fish. Bull. 63:611-618. 



Whitefish were tagged with spaghetti 

 streamer tags in June and July 1960 

 (1,122 fish; 15.4 inches average length) 

 and November 1959-61 (181 fish; 18.8 

 inches). Total recoveries were 374 fish 

 (28.7 percent); most recaptures came 

 within 2 years after tagging. Over half 

 of the recoveries were within 5 nniles 

 of the tagging site, and the greatest 



distance traveled was 25 miles. Growth 

 of fish tagged in June and July 1960 was 

 1.6 inches the first year and 1.2 the 

 second. Of 27 fish recaptured within 6 

 months after tagging in November, 17 

 (63 percent) had decreased in length. 

 Estimated annual exploitation rates 

 were 22.6 percent for whitefish tagged 

 in June and July and 20.5 percent for 

 those tagged in November; true rates 

 are believed to be higher. 



DRYER, WILLIAM R., and JOSEPH BEIL. 

 1964. Life history of lake herring in Lake 

 Superior. U.S. Fish Wildl. Serv., Fish. 

 Bull. 63:493-530. 



Samples from commercial landings at 

 Duluth, Minn., in 1957-59 and at Bay- 

 field, Wis., Portage Entry, Mich., and 

 Marquette, Mich., in 1950-59 permitted 

 comparisons among localities and study 

 of trends in certain aspects of the life 

 history of lake herring. Growth rate in- 

 creased from west to east as did also 

 the mean size of fish captured and the 

 mean weight of fish at a given length. 

 At Bayfield, Portage Entry, and Mar- 

 quette, growth was faster and fish were 

 heavier, length for length, in 1956-59 

 than in 1950-55. Annual fluctuations of 

 growth rate were similar at the three 

 ports. Age-group IV was dominant in 

 all samples. Strength of year classes 

 1946-55 varied widely but had a broad 

 downward trend. Fluctuations of year 

 classes were similar at Marquette and 

 Bayfield but at both ports did not re- 

 semble fluctuations at Portage Entry. 

 All lake herring older than the III group 

 were mature. Females outnumbered 

 males (68.5:31.5). Information is given 

 also on egg production, spawning, sea- 

 sonal distribution, and food. 



DUDEN, WILLIAM R. 



1933. Recent advances in the fishing in- 

 dustry. The Fisherman (Grand Haven, 

 Mich.) 2(10):3-4. 10-11; 2(12):3-4, 10. 



Summary of developments in process- 

 ing, transportation, marketing, adver- 

 tising, and the utilization of byproducts. 



DUDEN, WILLIAM R., vide: RALPH HILE. 



EBEL, WESLEY J. 



1962. A photoelectric amplifier 

 detector. Great Lakes Fish, 

 Tech. Rep. 4:19-26. 



as a dye 

 Comm., 



Describes a detector designed to re- 

 cord automatically the arrival of fluo- 

 rescent dye at predetermined points on 

 a stream. The instrument operates 



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