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Lake fisheries need lamprey control and research
Since 1921, when the first sea lamprey was recorded from Lake Erie, concern about this parasite in the Great Lakes above Niagara Falls, where previously it had never occurred, grew successively. At first, the concern was shared only in scientific circles, but as the parasite continued its persistent and rapid spread throughout the upper Great Lakes this concern was voiced by state conservation departments, the U.S. Fish and Wildlife Service, and interested fishermen. Catches of lake trout especially, and other species secondarily, began to fall below anything representing normal fluctuations in abundance. The fishing industry on Lake Huron and Lake Michigan became extremely concerned due to the fact that income was diminishing greatly. Producers on Lake Superior were fearful that the same decline in production would soon characterize their fishery.
Investigation of method of measuring twine in Great Lakes district
Abstract has not been submitted
Review of Great Lakes work conducted by the U. S. Bureau of Fisheries
Abstract has not been submitted
Preliminary report on investigation of chubnet meshes in Lake Michigan
Abstract has not been submitted
Lake states change fishery regulations
Following methods described by Louis Bureau (1911, 1913) in France,tabulations were made (1) of the ages at which captivity-reared bob-white quail (Colinus virginianus) dropped their juvenal remiges, and (2) the rates at which post-juvenal replxcement primaries grew. These were arranged so as to permit the determination of age in healthv birds from one to five months of age. The degree of individual variation was much greater than that found by Bureau, however. and limits accuracy in age determination after the 10th week..... The post-juvenal wing molt began on the birds' 28th day and ended when the quail were 146 to 154 days old.The post-juvenal body molt was found to take place largely between the 70th and 100th days. The juvenal rectrices were renewed from the 62nd to the 122nd days, the new feathers being as long as their longest coverts when the birds were 116 days old. The color of the tarsi varied from pink, at 32 days of age, to straw color at 60 days, and yellow-gray from 83 to 180 days. At six months, the color of the beak was identical with that of adults.....Unlike several other game bird species, the flexibility of the lower jaw was not an accurate index to age in bob-whites older than 11 weeks. Rigor mortis and freezing were found to hinder the testing of this criterion.
Lake fisheries facing extermination: disappearance of valuable species causes alarm
Abstract has not been submitted
Mortality of fish in Lake Erie
The food habits of Blue Grouse vary from a simple winter diet that is made up predominantly of coniferous needles to a complex diet during the summer months, characterized by great variety of foods including green leaves, fruits and seeds, flowers, animal matter and coniferous needles. The spring and fall, which represent the transition periods between these two, are characterized by feeding habits that are generally intermediate. The diets of the two species of Blue Grouse, Dendrugapus obscurus and Dendragapus juliginosus, are quite similar as far as major types of food are concerned, but they differ considerably in the species that are taken. Such differences reflect differences in the vegetation within the ecologic and geographic ranges occupied by the two species.
Progress report on the sea lamprey study
SUMMARY: The Peromyscus leucopus on a 17-acre study area were live-trapped, marked, and released over a seven-day period. On the three following nights intensive snap-trapping was done on the central acre of the study plot. The animals caught by snap traps in the central acre represented the population of the central acre and several surrounding acres. By the currently accepted methods of interpreting snap-trap data, the population per acre would be considered to be 23 adults. The live-trap data show that the true population was between six and seven adults per acre. Modern methods of live-trapping are shown to be valid for population studies. Two methods are presented for the conversion of live-trap data into per acre figures. Errors involved in the current use of snap-trap data are discussed and snap-trap methods are shown to be invalid for determining actual population numbers. It should be practical to use a snap-trap quadrant technique to obtain a relative measure or index figure for small mammal populations.