Publications

Returns from mature lake trout (Salvelinus namaycush) tagged in western Lake Superior in 1959 and 1962-65 described here suggest that trout disperse widely from the spawning grounds after spawning and return in subsequent years. Although the data were not extensive, returns from lake trout tagged near Keweenaw Point in 1950 and off Marquette, Michigan, in 1952 suggested similar movement. Loftus st

The chemicals used to control the sea lamprey, Petromyzon marinus, in the Great Lakes have drastically reduced populations of larval lampreys in tributary streams. These larvicides are too costly and difficult to apply, however, in inland lakes, estuaries, and bays. Populations of sea lampreys in these areas constitute a threat to the refinement of the control. The gear available to locate, amp

The life history of the landlocked sea lamprey, Petromyzon marinus, has been described by several authors, the two most recent of which are Applegate and Wigley. The only information on the production of larvae from nests of the sea lamprey was reported by Applegate, who counted the larvae from three nests in the Ocqueoc River, a tributary of Lake Huron. The present report presents data on the hat

Hermaphroditism has been reported frequently among many of the Clupeidae, but only one account of hermaphroditism has been published for the alewife, Alosa pseudoharengus. Rothschild discovered four hermaphroditic alewives among 444 fish he examined from Cayuga Lake, New York. We recently collected two hermaphroditic alewives from Lake Michigan. Both fish were normal in external appearance but

A STUDY OF MIGRATORY BEHAVIOR of parasitic sea lampreys (Petromyzon marinus) in the Great Lakes required a means of capturing lampreys for tagging and releasing in St. Marys River, Lake Huron. Smith and Elliott (1953) fished specially made gill and trap nets for sea lampreys, but stationary nets could not be used in the St. Marys River because of boat traffic, interference with sport fishermen, an

Marked success of rehabilitation of lake trout in Lake Superior has been due principally to the control of the sea lamprey and closure of the lake trout fishery in 1962 and large-scale plantings of yearling lake trout in 1959-66. After the sea lamprey became established in the late 1940s, spawning stocks of lake trout began to decrease and were almost nonexistent by 1960-61. After control of the s

Scales from known-age coregonids reared in the laboratory were examined to determine when annuli formed and to learn possible factors of their formation. Scales were taken monthly from marked fish for periods up to 21 months. Scales were also examined from fish that died and from preserved specimens of young-of-the-year for each species. Two marks formed on almost all scales each calendar year. Th

Studies were based primarily on 3,097 bloaters collected in experimental gill nets and bottom trawls fished in 1958-65 in the Apostle Islands region of Lake Superior. The average size of bloaters increased considerably during the period. The percentage longer than 8.9 inches increased from 45% in 1959 to 99% in 1965. Calculated lengths were without exception higher in 1962-65 than in 1958-61. Grow

No abstract available.

Water quality of streams tributary to Lakes Superior and Michigan was analyzed for 142 stations on 99 streams tributary to Lake Superior and 83 stations on 56 streams tributary to Lake Michigan during 1962-65. Concentrations of aluminum, copper, and iron were not affected greatly by flow or season. Magnesium, calcium, chlorides, total alkalinity, total hardness, and conductivity varied with the fl

This study was conducted on five streams tributary to Lake Superior and four tributary to Lake Michigan. Samples of the bottom fauna before and after chemical treatment revealed that most groups of aquatic organisms were not adversely affected by exposure to larvicides. The total number of invertebrates was smaller 1 week after treatment than before treatment, increased somewhat by 6 weeks after t

Aflatoxins (toxic metabolites of the mold Aspergillus flavus) were present in a commercial trout ration causing hepatoma in rainbow trout. Cottonseed meal and solvent extracts of cottonseed meal and of rations containing cottonseed meal and peanut meal were found by chemical assay and confirmed by duckling assay to contain aflatoxins. Diets containing these materials and a purified test diet to wh