Redescription of Pennella instructa Wilson, 1917 (Copepoda: Pennellidae) from the swordfish (Xiphias gladius L.)

W. E. Hogans

doi:10.1139/z86-107

Redescription of Pennella instructa Wilson, 1917 (Copepoda: Pennellidae) from the swordfish (Xiphias gladius L.)

Canadian Journal of Zoology ◽

10.1139/z86-107 ◽

1986 ◽

Vol 64 (3) ◽

pp. 727-730 ◽

Cited By ~ 5

Author(s):

W. E. Hogans

Keyword(s):

Atlantic Ocean ◽

Georges Bank ◽

Northwest Atlantic ◽

Lateral Horn ◽

Xiphias Gladius

Two specimens of Pennella instructa Wilson, 1917 are described from swordfish (Xiphias gladius L.) collected off Georges Bank in the northwest Atlantic Ocean. This mesoparasitic copepod is characterized by two lateral horn holdfasts extending posteriorly parallel to the neck, distinct groups of papillae on the anterior end of the cephalothorax, and five-segmented and setose first antennae.

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Pennella filosa and Pennella instructa (Copepoda: Pennellidae) on Swordfish (Xiphias gladius L.) from the Northwest Atlantic Ocean

Journal of Parasitology ◽

10.2307/3281987 ◽

1985 ◽

Vol 71 (1) ◽

pp. 111 ◽

Cited By ~ 7

Author(s):

William E. Hogans ◽

John Brattey ◽

Thomas R. Hurlbut

Keyword(s):

Atlantic Ocean ◽

Northwest Atlantic ◽

Xiphias Gladius

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Compressional velocities from multichannel refraction arrivals on Georges Bank—northwest Atlantic Ocean

Geophysics ◽

10.1190/1.1440992 ◽

1979 ◽

Vol 44 (6) ◽

pp. 1022-1033 ◽

Cited By ~ 5

Author(s):

L. D. McGinnis ◽

R. M. Otis

Keyword(s):

Atlantic Ocean ◽

Velocity Distribution ◽

Vertical Velocity ◽

Georges Bank ◽

Overburden Pressure ◽

Northwest Atlantic ◽

The North ◽

Continuous Coverage ◽

Velocity Gradients ◽

North Edge

Velocities were obtained from unreversed, refracted arrivals on analog records from a 48‐channel, 3.6-km hydrophone cable (3.89 km from the airgun array to the last hydrophone array). Approximately 200 records were analyzed along 1500 km of ship track on Georges Bank, northwest Atlantic Ocean, to obtain regional sediment velocity distribution to a depth of 1.4 km below sea level. This technique provides nearly continuous coverage of refraction velocities and vertical velocity gradients. Because of the length of the hydrophone cable and the vertical velocity gradients, the technique is applicable only to the Continental Shelf and the shallower parts of the Continental Slope in water depths less than 300 m. Sediment diagenesis, the influence of overburden pressure on compaction, lithology, density, and porosity are inferred from these data. Velocities of the sediment near the water‐sediment interface range from less than 1500 m/sec on the north edge of Georges Bank to 1830 m/sec for glacial deposits in the northcentral part of the bank. Velocity gradients in the upper 400 m range from [Formula: see text] on the south edge of the bank to [Formula: see text] on the north. Minimum gradients of [Formula: see text] were observed south of Nantucket Island. Velocities and velocity gradients are explained in relation to physical properties of the Cretaceous, Tertiary, and Pleistocene sediments. Isovelocity contours at 100-m/sec intervals are nearly horizontal in the upper 400 m. Isovelocity contours at greater depths show a greater difference from a mean depth because of the greater structural and lithological variation. Bottom densities inferred from the velocities range from 1.7 to [Formula: see text] and porosities range from 48 to 62 percent. The most significant factor controlling velocity distribution on Georges Bank is overburden pressure and resulting compaction. From the velocity data we conclude that Georges Bank has been partially overridden by a continental ice sheet.

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