28 



COMMERCIAL FISHERIES REVIEW 



Vol. 28, No. 7 



ber of small streams in Green Bay treated 

 four years ago also showed a lack of rees- 

 tablished populations. 



Lake Michigan Research: The Bureau's 

 research vessel Cisco completed its first 

 cruise of the season on April 16, Collections 

 of alewives and chubs were obtained to pro- 

 vide material for the alewife experiments 

 and pesticide studies. Following the cruise, 

 the vessel was taken to drydock at Sturgeon 

 Bay, Wis., where the hull was sandblasted 

 and repainted. 



Experiments on the interrelationship of 

 alewives with yellow perch and smelt were 

 initiated. Mature yellow perch held at the 

 laboratory for an egg supply spawned suc- 

 cessfully. Although the yearling alewives 

 held in the laboratory did not eat the perch 

 eggs, they readily ate the newly hatched lar- 

 vae. Adult smelt and smelt eggs also were 

 acquired. Alewives fed on both the eggs and 

 the young smelt fry. In addition, rainbow 

 trout eggs are being held for hatching. This 

 species initially will serve as a substitute 

 for lake trout to permit preliminary investi- 

 gations to get underway. 



Lake Superior Research : All contract 

 fishermen hired by the Bureau of Commer- 

 cial Fisheries in the biological sampling of 

 lake trout in Lake Superior began fishing 

 their grounds in April except one fisherman 

 on Isle Royale. The inshore waters along 

 the east shore of Keweenaw Peninsula pro- 

 duced good fishing. The fishing offshore of 

 the Huron Islands was less than a year ago. 

 Scarring by sea lampreys was lower except 

 in Keweenaw Bay where fresh wounds were 

 twice as numerous as a year earlier. In 

 the Marquette area, scarring was down by 

 30 percent. 



The Bureau's research vessel Siscowet 

 began operating on Lake Superior during the 

 final week of the month. A 4 -day cruise in 

 Minnesota waters of Lake Superior in coop- 

 eration with the University of Minnesota cov- 

 vered the herring grounds north of Duluth. 

 Townets were used to sample larval fish pop- 

 ulations. Larval fish were readily captured 

 and many were still in the yolk-sac stage. 

 Bottom trawling also was carried out on the 

 herring grounds with coregonid species oc- 

 curing predominantly in the catches. 



Lake Erie Research : The spring sam- 

 pling of the commercial landings of yellow 



pike (walleyes) and yellow perch was com- 

 pleted during the month. Over 1,000 of each 

 species were examined at the south shore 

 ports. Data also were collected for compar- 

 ative fecundity studies of both species in each 

 of the three basins of Lake Erie. Samples of 

 fish for studies of pesticide residues in fish 

 flesh were collected and shipped to the Bu- 

 reau's laboratory in Ann Arbor. 



The research vessel Musky II carried out 

 routine operations in the western basin of 

 Lake Erie in April --servicing thermographs 

 and experimental sediment collectors located 

 in strategic areas. Preliminary trawling was 

 carried on to determine winter mortality rates 

 in fish populations. 



Note: See Commercial Fisheries Review , January 1966 p. 35, 

 and February 1966 p. 19. 



CHEMICAL TREATMENT OF 

 SEA LAMPREY -PRODUCING 

 STREAMS CONTINUED: 



With the State of Michigan Conservation 

 Department's approval, the U, S, Department 

 of the Interior's Bureau of Commercial Fish- 

 eries resumed in late April 1966, its chemi- 

 cal war on sea lampreys in Michigan streams 

 still harboring the eel-like killers. About 60 

 tributaries of Lakes Superior, Michigan, and 

 Huron are on the Bureau's list for treatment 

 through the end of June 1967. 



Final applications of chemicals in 2 streams 

 in Michigan and several Indiana streams will 

 complete the first round of treatments in lam- 

 prey-producing tributaries of Lake Michigan. 



Starting in late April, the Bureau hoped 

 to mount its first all-out offensive against 

 lampreys in Lake Huron streams where 48 

 rivers and creeks are scheduled for treat- 

 ment within the next 3 or 4 years. 



A total of 16 streams are scheduled for 

 first treatment this summer and 2 are on 

 tap for their second application of chemicals. 



On Lake Michigan, where streams were 

 still too high for chemical work to begin in 

 late AprU., the Bureau planned to re-treat 27 

 streams which had re-established sea lam- 

 prey populations. 



Starting in the summer of 1966, chemical 

 treatment will again be applied to 19 Lake 

 Superior streams, 15 in Michigan and 4 in 

 Wisconsin. 



