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Geology topics

R. S. Jones

Publications and source records attributed to R. S. Jones.

5 recordsLinked to original sources

Sidescan sonar as a tool for detection of demersal fish habitats

Sidescan sonar can be an effective tool for the determination of the habitat distribution of commercially important species. This technique has the advantage of rapidly mapping large areas of the seafloor. Sidescan images (sonographs) may also help to identify appropriate fishing gears for different types of seafloor or areas to be avoided with certain types of gears. During the early stages of exploration, verification of sidescan sonar sonographs is critical to successful identification of important habitats. Tilefishes ( Lopholatilus and Caulolatilus ) are especially good target species because the construct large burrows in the seafloor or live around boulders, both of which are easily detectable on sonographs. In some special circumstances the estimates of tilefish burrow densities from sonographs can be used to estimate standing stock. In many localities the burrow and boulder habitats of tilefish are shared with other commercially important species such as American lobsters, Homarus americanus ; cusk, Brosme brosme ; and ocean pout, Macrozoarces americanus .

Fishery Bulletin

The role of erosion by fish in shaping topography around Hudson submarine canyon.

An 800-km 2 area of rough topography around the head of Hudson Canyon off the eastern United States is attributed to erosion by tilefish ( Lopholatilus chamaeleonticeps ) and associated species of crustaceans. The rough topography has a relief of 1-10 m, occurs in water depths of 120-500 m, and has been cut into a semilithified, silty clay substrate since the onset of the Holocene transgression. Commercial fishing activity indicates that a large population of tilefish, which dig burrows in the sea floor, occupy the area of the rough topography. Average tilefish burrows are 1.6 m in diameter and 1.7 m in depth. They have a clustered, not uniform, distribution, and their average density is 2,500 per km 2 . The close match of areas of rough topography and high tilefish populations, the active burrowing of the sea floor, and the clustered distribution of the burrows suggest that the hummocky topography in this area may be the result of continuous erosion by tilefish and associated crustaceans during the Holocene. An erosion rate of 13 cm per 1,000 years is necessary to create this topography during the past 13,000 years--and 18 cm per 1,000 years if(as is more likely based on the depths at which tilefish presently are found) the erosion started 9,000 years ago.

New York

Stratigraphic sections of the Phosphoria Formation in Montana, 1949-50: part II

The U.S. Geological Survey has recently measured and sampled the Phosphoria formation at many localities in Montana and other western states. These data will not be fully synthesized and analyzed for several years, but segments of the data, accompanied by little or no interpretation, are published as preliminary reports as they are assembled. This report, which contains abstracts of many of the sections in southwestern Montana (fig. 1), is one of this series and is the fourth Montana report; it includes the second half of the data gathered in Montana during 1949 and 1950. The field and laboratory procedures adopted in these investigations are described rather fully in a previous report (McKelvey and others, 1953). Many people have taken part in this investigation. The program of which this work is a part was organized by V. E. McKelvey. J. L. Elliott, W. J. Garmoe, R. F. Gosman, C. W. Tandy, and W. H. Wilson participated in the description of strata and the collection of samples referred to in this report. Crushing and splitting of the samples in the field was done by T. K. Rigby. The laboratory preparation of samples for chemical analysis was done in Denver, Colo., under the direction of W. P. Huleatt.

Montana