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Articles 1 - 9 of 9
Full-Text Articles in Physical Sciences and Mathematics
Recovery Plan For The Blue Whale (Balaenoptera Musculus), Randall R. Reeves, Phillip J. Clapham, Robert L. Brownell Jr., Gregory K. Silber
Recovery Plan For The Blue Whale (Balaenoptera Musculus), Randall R. Reeves, Phillip J. Clapham, Robert L. Brownell Jr., Gregory K. Silber
United States Department of Commerce: Staff Publications
Recovery plans identify reasonable actions which are believed to be required to recover and/or protect endangered species. Plans are prepared by the National Marine Fisheries Service (NMFS) and the U.S. Fish and Wildlife Service (FWS) and sometimes with the assistance of recovery teams, contractors, State agencies, and others. This plan was prepared by Randall R. Reeves, Phillip J. Clapham, Robert L. Brownell, Jr., and Gregory K. Silber for NMFS. Recovery plans do not necessarily represent the views nor the official positions or approvals of any individuals or agencies, other than those of NMFS, and they represent the views of NMFS …
Seasonal Variation In Reception Of Fin Whale Calls At Five Geographic Areas In The North Pacific
Seasonal Variation In Reception Of Fin Whale Calls At Five Geographic Areas In The North Pacific
United States Department of Commerce: Staff Publications
In late August 1991 scientists at the National Oceanic and Atmospheric Administration’s (NOAA) National Marine Mammal Laboratory (NMML) and Pacific Marine Environmental Laboratory (PMEL) began a pilot study to investigate the capability of hydrophones from the US. Navy’s fixed array system to detect large whales in the North Pacific by passive reception of their calls. PMEL had previously established a direct data link from five bottom-mounted arrays of the Navy SOSUS (Sound Surveillance System), via the Naval Oceanographic Processing Facility (NOPF) at Whidbey Island, Washington, to study low-level seafloor seismicity (Fox et al. 1994). PMEL subsequently provided NMML tapes of …
Declines In Benthic Macroinvertebrate Populations In Southern Lake Michigan, 1980–1993, Thomas F. Nalepa, David J. Hartson, David L. Fanslow, Gregory A. Lang, Stephen J. Lozano
Declines In Benthic Macroinvertebrate Populations In Southern Lake Michigan, 1980–1993, Thomas F. Nalepa, David J. Hartson, David L. Fanslow, Gregory A. Lang, Stephen J. Lozano
United States Department of Commerce: Staff Publications
Densities of the major benthic macroinvertebrate groups declined dramatically at sites shallower than 50 m in southern Lake Michigan between 1980 and 1993. Declines in Diporeia, Oligochaeta, and Sphaeriidae ranged from 40 to 75% at these depths. Total densities declined from 16 800·m–2 in 1980–1981 to 4800·m–2 in 1992–1993 at sites in the 16–30 m depth interval and from 21 300 to 11 300·m–2 at sites in the 31–50 m depth interval. Changes at sites deeper than 50 m were minimal; only sphaeriids declined to any extent. Declines in oligochaetes and sphaeriids occurred uniformly throughout the …
Population Growth Of Antarctic Fur Seals: Limitation By A Top Predator, The Leopard Seal?, Peter L. Boveng, Lisa M. Hiruki, Michael K. Schwartz, John L. Bengtson
Population Growth Of Antarctic Fur Seals: Limitation By A Top Predator, The Leopard Seal?, Peter L. Boveng, Lisa M. Hiruki, Michael K. Schwartz, John L. Bengtson
United States Department of Commerce: Staff Publications
Antarctic fur seals (Arctocephalus gazella) in the South Shetland Islands are recovering from 19th-century exploitation more slowly than the main population at South Georgia. To document demographic changes associated with the recovery in the South Shetlands, we monitored fur seal abundance and reproduction in the vicinity of Elephant Island during austral summers from 1986/1987 through 1994/1995. Total births, mean and variance of birth dates, and average daily mortality rates were estimated from daily live pup counts at North Cove (NC) and North Annex (NA) colonies on Seal Island. Sightings of leopard seals (Hydrurga leptonyx) and incidents …
Seasonal Patterns In The Abundance And Distribution Of California Cetaceans, 1991-1992, Karin A. Forney, Jay Barlow
Seasonal Patterns In The Abundance And Distribution Of California Cetaceans, 1991-1992, Karin A. Forney, Jay Barlow
United States Department of Commerce: Staff Publications
This study presents a detailed seasonal comparison of the abundance and distribution of cetaceans within 100-150 nmi (185-278 km) of the California coast during 1991 and 1992. The results of a shipboard line-transect survey conducted in July-November 1991 (“summer”) were compared to those from aerial line-transect surveys conducted in March-April 1991 and February-April 1992 (“winter”). Using a confidence-interval-based bootstrap procedure, abundance estimates for six of the eleven species included in the comparison exhibited significant (a = 0.05) differences between the winter and summer surveys. Pacific white-sided dolphins (Lagenorhynchus obliquidens), Risso’s dolphins (Grampus griseus), common dolphins ( …
Foraging Modes Of Chinstrap Penguins: Contrasts Between Day And Night, John K. Jansen, Peter L. Boveng, John L. Bengtson
Foraging Modes Of Chinstrap Penguins: Contrasts Between Day And Night, John K. Jansen, Peter L. Boveng, John L. Bengtson
United States Department of Commerce: Staff Publications
Penguins rely on vision to travel and hunt at sea. Vision in marine predators, particularly those hunting phototactic prey under a broad range of light intensities, must be better understood to realize how these species respond to changes in their environment. We studied the effects of daily cycles in light intensity on visual predators by examining the duration and timing of chinstrap penguins' Pygoscelis Antarctica foraging trips and the size, composition, and timing of their meals. We used radio telemetry and stomach-contents sampling to study adult penguins that were provisioning chicks during the summers of 1993 and 1994 at Seal …
Letter To The Editor: Source Of Polynuclear Aromatic Hydrocarbons In Prince William Sound, Alaska, Usa, Subtidal Sediments, Jeffrey W. Short, Ron A. Heintz
Letter To The Editor: Source Of Polynuclear Aromatic Hydrocarbons In Prince William Sound, Alaska, Usa, Subtidal Sediments, Jeffrey W. Short, Ron A. Heintz
United States Department of Commerce: Staff Publications
Recently Page and coworkers concluded that polynuclear aromatic hydrocarbons (PAHs) detected in the deeper subtidal sediments of Prince William Sound, Alaska, USA, derive from oil seeps in the northern Gulf of Alaska. Coal was erroneously dismissed as an alternative source of these PAHs, based on the claimed absence of reported coal deposits east of the Bering River coal field. The reference given to support this claim is apparently a geological map of western Prince William Sound. This map is irrelevant. In fact, a substantial coal field lies east of the Bering River field in the Robinson Mountains near Cape Yakataga.
Stable Isotope Analyses Of Tooth Annuli Reveal Temporal Dietary Records: An Example Using Stellar Sea Lions, Keith Hobson, John Sease
Stable Isotope Analyses Of Tooth Annuli Reveal Temporal Dietary Records: An Example Using Stellar Sea Lions, Keith Hobson, John Sease
United States Department of Commerce: Staff Publications
Stable isotope analysis of teeth of marine mammals can provide valuable information on trophic level and source of feeding. However, the isotopic analysis of whole teeth presents only an average dietary estimate for individuals across the period of growth of that tooth. While such analyses can be valuable, particularly in the case of fossil material, in contrast, isotopic analysis of individual annuli of teeth can provide dietary information for each year of tooth growth, in some cases representing the whole of the animal's life. We measured stable-carbon isotope ratios (13C/12C) in the inorganic (hydroxyapatire) and stable-nitrogen …
Sounds Recorded From Baird's Beaked Whale, Berardius Bairdii, Stephen Dawson, Jay Barlow, Don Ljungblad
Sounds Recorded From Baird's Beaked Whale, Berardius Bairdii, Stephen Dawson, Jay Barlow, Don Ljungblad
United States Department of Commerce: Staff Publications
The vocal behavior of ziphiid whales is very poorly known. Free-swimming northern bottlenose whales, Hyperoodon ampullatus, have been recorded producing 3-16 kHz whistles and chirps (Winn et al. 1970; linear equipment frequency response 500 Hz-14 kHz) and 20-30 kHz ultrasonic clicks (Fauchner and Whitehead, unpublished data; equipment response to 35 kHz). A free-swimming mesoplodont beaked whale (probably Mesoplodon hertori) produced ultrasonic clicks (Ljungblad, unpublished data; equipment frequency response to 32 kHz). Sounds have been recorded from a stranded Blainville's beaked whale, Mesoplodon densirostris (Caldwell and Caldwell 1971; equipment frequency response 40 Hz-20 kHz) and a post-stranding, captive …