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Full-Text Articles in Physical Sciences and Mathematics
Japan’S Whaling Plan Under Scrutiny, Nicholas J. Gales, Toshio Kasuya, Phillip J. Clapham, Robert L. Brownell Jr.
Japan’S Whaling Plan Under Scrutiny, Nicholas J. Gales, Toshio Kasuya, Phillip J. Clapham, Robert L. Brownell Jr.
United States Department of Commerce: Staff Publications
Eighteen years after initiating scientific whaling in Antarctic waters, Japan presented a new and more ambitious program to the International Whaling Commission (IWC); the proposal was made in early June during the IWC’s annual meeting in Ulsan, Korea. Japan now wishes to more than double its annual catch of Antarctic minke whales (from about 440 to 935), and to expand lethal sampling to include an additional yearly take of 50 humpback and 50 fin whales. Unlike catches for commercial whaling, scientific catches are unregulated. Since 1987, Japan has taken some 6,800 minke whales from Antarctic waters, despite ongoing criticism of …
Catches Of Humpback Whales In The Southern Ocean, 1947-1973, Phil Clapham, Yuri Mikhalev, Wally Franklin, David Paton, Scott Baker, Robert L. Brownell Jr.
Catches Of Humpback Whales In The Southern Ocean, 1947-1973, Phil Clapham, Yuri Mikhalev, Wally Franklin, David Paton, Scott Baker, Robert L. Brownell Jr.
United States Department of Commerce: Staff Publications
We review catches of humpback whales (Megaptera novaeangliae) in the Southern Ocean during the period following World War II, with an emphasis on Areas IV, V and VI (the principal regions of illegal Soviet whaling on this species). Where possible, we summarize legal and illegal Soviet catches by year, Area and factory fleet, and also include information on takes by other nations. Soviet humpback catches between 1947 and 1973 totaled 48702 and break down as follows: 649 (Area I), 1412 (Area II), 921 (Area III), 8779 (Area IV), 22569 (Area V) and 7195 (Area VI), with 7177 catches not assignable …
Preliminary Evaluation Of A Lake Whitefish (Coregonus Clupeaformis) Bioenergetics Model, Charles P. Madenjian, Stephen A. Pothoven, Philip J. Schneeberger, Daniel V. O'Connor, Stephen B. Brandt
Preliminary Evaluation Of A Lake Whitefish (Coregonus Clupeaformis) Bioenergetics Model, Charles P. Madenjian, Stephen A. Pothoven, Philip J. Schneeberger, Daniel V. O'Connor, Stephen B. Brandt
United States Department of Commerce: Staff Publications
We conducted a preliminary evaluation of a lake whitefish (Coregonus clupeaformis) bioenergetics model by applying the model to size-at-age data for lake whitefish from northern Lake Michigan. We then compared estimates of gross growth efficiency (GGE) from our bioenergetics model with previously published estimates of GGE for bloater (C. hoyi) in Lake Michigan and for lake whitefish in Quebec. According to our model, the GGE of Lake Michigan lake whitefish decreased from 0.075 to 0.02 as age increased from 2 to 5 years. In contrast, the GGE of lake whitefish in Quebec inland waters decreased from …
Implantation Of Subcutaneous Radio Transmitters In The Harbor Seal (Phoca Vitulina), Michelle Lander, Martin Haulena, Frances Gulland, James Harvey
Implantation Of Subcutaneous Radio Transmitters In The Harbor Seal (Phoca Vitulina), Michelle Lander, Martin Haulena, Frances Gulland, James Harvey
United States Department of Commerce: Staff Publications
Radio telemetry has become a standard tool for studying the behavior, physiology, life history traits, and population dynamics of marine mammals. Radio transmitters typically are attached to the hind flippers of pinnipeds or glued to the fur using marine epoxy or other cyanocrylare adhesives (Fedak et al. 1983, Bengtson 1993, Jeffries et al. 1993). Longterm data acquisition is difficult, however, because radio-flipper transmitters commonly tear from the webbing of the flipper and instruments that are glued to the fur are shed during the seasonal molt.
Relating Results Of Chronic Toxicity Responses To Population-Level Effects: Modeling Effects On Wild Chinook Salmon Populations, Julann A. Spromberg, James P. Meador
Relating Results Of Chronic Toxicity Responses To Population-Level Effects: Modeling Effects On Wild Chinook Salmon Populations, Julann A. Spromberg, James P. Meador
United States Department of Commerce: Staff Publications
Standard toxicity tests assess the physiological responses of individual organisms to exposure to toxic substances under controlled conditions. Time and space restrictions often prohibit the assessment of population-level responses to a toxic substance. Compounds affecting various toxicity endpoints, such as growth, fecundity, behavior, or immune function, alter different demographic traits and produce different impacts on the population. Chronic effects of immune suppression, reproductive impairment, and growth reduction were examined using life history models for Chinook salmon (Oncorhynchus tshawytscha). Modeled immune suppression acted through reductions in age-specific survival, with first- and secondyear survival producing the greatest changes in the …
Ringed And Bearded Seal Densities In The Eastern Chukchi Sea, 1999–2000, John L. Bengtson, Lisa M. Hiruki-Raring, Michael A. Simpkins, Peter L. Boveng
Ringed And Bearded Seal Densities In The Eastern Chukchi Sea, 1999–2000, John L. Bengtson, Lisa M. Hiruki-Raring, Michael A. Simpkins, Peter L. Boveng
United States Department of Commerce: Staff Publications
Aerial surveys were conducted in 1999 and 2000 to estimate the densities of ringed (Phoca hispida) and bearded (Erignathus barbatus) seals in the eastern Chukchi Sea. Survey lines were focused mainly on the coastal zone within 37 km of the shoreline, with additional lines flown 148–185 km offshore to assess how densities of seals changed as a function of distance from shore. Satellite-linked time-depth recorders were attached to ringed seals in both years to evaluate the time spent basking on the ice surface. Haulout patterns indicated that ringed seals transitioned to basking behavior in late May …
Estimates Of Sperm Whale Abundance In The Northeastern Temperate Pacific From A Combined Acoustic And Visual Survey, Jay Barlow, Barbara L. Taylor
Estimates Of Sperm Whale Abundance In The Northeastern Temperate Pacific From A Combined Acoustic And Visual Survey, Jay Barlow, Barbara L. Taylor
United States Department of Commerce: Staff Publications
We estimate the abundance of sperm whales in a 7.8 million km2 study area in the eastern temperate North Pacific using data from a ship-based acoustic and visual line-transect survey in spring 1997. Sperm whales were detected acoustically using a hydrophone array towed at 15 km/h and 100 m depth. The hydrophone array was towed for 14,500 km, and locations were estimated acoustically for 45 distinct sperm whale groups. Whales producing slow clicks (>2-s period) were detected at greater distance (up to 37 km), and the estimation of effective strip widths was stratified based on initial click period. …
Fatigue Sensitivity Of Y-Tzp To Microscale Sharp-Contact Flaws, Yu Zhang, Brian R. Lawn
Fatigue Sensitivity Of Y-Tzp To Microscale Sharp-Contact Flaws, Yu Zhang, Brian R. Lawn
United States Department of Commerce: Staff Publications
The strength degrading effects of sharp-contact damage are examined for Y-TZP ceramic plates bonded to a plastic substrate. Contacts are made with Vickers and Berkovich diamond indenters at low loads (0.1 N to 100 N) in the ceramic lower surfaces prior to bonding to the substrates. The indentations remain in the subthreshold region, that is, without visible corner radial cracks, over the lower region (< 10 N) of the load range. A concentrated load is then applied sinusoidally to the ceramic upper surface, with the loading axis centered on the subsurface indentation flaw, thereby subjecting the flaw to cyclic tension. Relative to polished surfaces, the indentations diminish the single-cycle strength by an amount that increases with increasing indentation load. The critical number of cycles required to cause failure from the indentation flaws is then measured at specified maximum lower surface tensile stresses. At each indentation load, the strength of the ceramic plates diminishes with increased cycling. The scale of degradation is compared with that from previous studies on Y-TZP surfaces containing larger-scale surface damage: sandblast damage, as used in dental crown preparation; and blunt-contact trauma from a spherical indenter at 3000 N. These other damage modes are shown to be equivalent in their strength-degrading capacity to diamond pyramid indentations in the microscale load range 0.1 N to 1 N, attesting to the highly deleterious nature of sharp particulate contacts. The mechanism of fatigue is considered in terms of microcrack evolution within the indentation damage zone.
Population Histories Of Right Whales (Cetacea: Eubalaena) Inferred From Mitochondrial Sequence Diversities And Divergences Of Their Whale Lice (Amphipoda: Cyamus), Zofia A. Kaliszewska, Jon Seger, Victoria J. Rowntree, Amy R. Knowlton, Kim Marshalltilas, Nathalie J. Patenaude, Mariana Rivarola, Catherine M. Schaeff, Mariano Sironi, Wendy A. Smith, Tadasu K. Yamada, Susan G. Barco, Rafael Benegas, Peter B. Best, Moira W. Brown, Robert L. Brownell Jr., Robert Harcourt, Alejandro Carribero
Population Histories Of Right Whales (Cetacea: Eubalaena) Inferred From Mitochondrial Sequence Diversities And Divergences Of Their Whale Lice (Amphipoda: Cyamus), Zofia A. Kaliszewska, Jon Seger, Victoria J. Rowntree, Amy R. Knowlton, Kim Marshalltilas, Nathalie J. Patenaude, Mariana Rivarola, Catherine M. Schaeff, Mariano Sironi, Wendy A. Smith, Tadasu K. Yamada, Susan G. Barco, Rafael Benegas, Peter B. Best, Moira W. Brown, Robert L. Brownell Jr., Robert Harcourt, Alejandro Carribero
United States Department of Commerce: Staff Publications
Right whales carry large populations of three ‘whale lice’ (Cyamus ovalis, Cyamus gracilis, Cyamus erraticus) that have no other hosts. We used sequence variation in the mitochondrial COI gene to ask (i) whether cyamid population structures might reveal associations among right whale individuals and subpopulations, (ii) whether the divergences of the three nominally conspecific cyamid species on North Atlantic, North Pacific, and southern right whales (Eubalaena glacialis, Eubalaena japonica, Eubalaena australis) might indicate their times of separation, and (iii) whether the shapes of cyamid gene trees might contain information about changes in the population …
The Status Of Diporeia Spp. In Lake Ontario, 1994- 1997, Stephen J. Lozano, Jill V. Sharold
The Status Of Diporeia Spp. In Lake Ontario, 1994- 1997, Stephen J. Lozano, Jill V. Sharold
United States Department of Commerce: Staff Publications
Surveys of benthic macroinvertebrates conducted in Lake Ontario between 1994 and 1997 revealed a recent decline in Diporeia spp. (Amphipoda) abundance. The lowest population densities and summer biomass are in the eastern basin of the lake at all depths. Densities and biomass declined in the shallowest (10-50 m) depth zone between 1994 and 1997. Mean Diporeia spp. densities declined from 1412 m-2 to 1 m-2, and the total mean biomass declined from 0.66-g DW m-2 to 0.001 g-DW m-2. The latter represents an overall loss of about 5100 mt of biomass in the shallowest …
Characteristics And Potential Causes Of Declining Diporeia Spp. Populations In Southern Lake Michigan And Saginaw Bay, Lake Huron, Thomas F. Nalepa, David L. Fanslow, Gretchen Messick
Characteristics And Potential Causes Of Declining Diporeia Spp. Populations In Southern Lake Michigan And Saginaw Bay, Lake Huron, Thomas F. Nalepa, David L. Fanslow, Gretchen Messick
United States Department of Commerce: Staff Publications
Populations of the amphipods Diporeia spp. are declining in all of the Great Lakes except Lake Superior. We examine characteristics and potential causes of declines in southern Lake Michigan and outer Saginaw Bay, Lake Huron. Amphipod populations began to decline within 3-4 years after zebra mussels (Dreissena polymorpha) colonized both areas. In Lake Michigan, which was better studied, the decline occurred first in shallow waters (<30 m) and then progressed deeper (51-90 m). Between 1980- 1981 (pre-Dreissena) and 1998-1999 (post-Dreissena), densities at sites in these two depth intervals declined 92% and 58%, respectively. At a 45-m site in southeastern Lake Michigan, densities of Diporeia spp. …
Ecology Of The Lake Huron Fish Community, 1970–1999, Norine E. Dobiesz, David A. Mcleish, Randy L. Eshenroder, James R. Bence, Lloyd C. Mohr, Mark P. Ebener, Thomas F. Nalepa, Aaron P. Woldt, James E. Johnson, Ray L. Argyle, Joseph C. Makarewicz
Ecology Of The Lake Huron Fish Community, 1970–1999, Norine E. Dobiesz, David A. Mcleish, Randy L. Eshenroder, James R. Bence, Lloyd C. Mohr, Mark P. Ebener, Thomas F. Nalepa, Aaron P. Woldt, James E. Johnson, Ray L. Argyle, Joseph C. Makarewicz
United States Department of Commerce: Staff Publications
We review the status of the Lake Huron fish community between 1970 and 1999 and explore the effects of key stressors. Offshore waters changed little in terms of nutrient enrichment, while phosphorus levels declined in inner Saginaw Bay. Introduced mussels (Dreissena spp.) proliferated and may have caused a decline in Diporeia spp. This introduction could have caused a decline in lake whitefish (Coregonus clupeaformis) growth and condition, with serious repercussions for commercial fisheries. Bythotrephes, an exotic predatory cladoceran, and other new exotics may be influencing the fish community. Sea lampreys (Petromyzon marinus) remained prevalent, but …
Lake Whitefish And Diporeia Spp. In The Great Lakes: An Overview, Thomas F. Nalepa, Lloyd C. Mohr, Bryan A. Henderson, Charles P. Madenjian, Philip J. Schneeberger
Lake Whitefish And Diporeia Spp. In The Great Lakes: An Overview, Thomas F. Nalepa, Lloyd C. Mohr, Bryan A. Henderson, Charles P. Madenjian, Philip J. Schneeberger
United States Department of Commerce: Staff Publications
Because of growing concern in the Great Lakes over declines in abundance and growth of lake whitefish (Coregonus clupeaformis) and declines in abundance of the benthic amphipod Diporeia spp., a workshop was held to examine past and current trends, to explore trophic links, and to discuss the latest research results and needs. The workshop was divided into sessions on the status of populations in each of the lakes, bioenergetics and trophic dynamics, and exploitation and management. Abundance, growth, and condition of whitefish populations in Lakes Superior and Erie are stable and within the range of historical means, but …
Preliminary Investigations For Causes Of The Disappearance Of Diporeia Spp. From Lake Ontario, Ronald Dermott, Mohiuddin Munawar, Robert Bonnell, Silvina Carou, Heather Niblock, Thomas F. Nalepa, Gretchen Messick
Preliminary Investigations For Causes Of The Disappearance Of Diporeia Spp. From Lake Ontario, Ronald Dermott, Mohiuddin Munawar, Robert Bonnell, Silvina Carou, Heather Niblock, Thomas F. Nalepa, Gretchen Messick
United States Department of Commerce: Staff Publications
The amphipod Diporeia spp. comprised 60-80% of the benthos in offshore Lake Ontario and was an important food for fish. In eastern Lake Ontario, Diporeia spp. began disappearing in 1993 just after the arrival of dreissenid mussels. We compared survival of Diporeia spp. and Hyalella azteca in sediments from areas where Diporeia spp. populations had vanished with survival in sediments still inhabited. Survival was also examined in the presence of zebra mussel (Dreissena polymorpha) pseudofeces, filtered water from mussel cultures, and added bacteria. The Microtox® test indicated that sediment pore water was not toxic. Sediments from sites with …
Recovery And Decline Of Lake Whitefish In U.S. Waters Of Eastern Lake Ontario, 1980-2001, Randall W. Owens, Robert O'Gorman, Thomas H. Eckert, Brian F. Lantry, Dawn E. Dittman
Recovery And Decline Of Lake Whitefish In U.S. Waters Of Eastern Lake Ontario, 1980-2001, Randall W. Owens, Robert O'Gorman, Thomas H. Eckert, Brian F. Lantry, Dawn E. Dittman
United States Department of Commerce: Staff Publications
The lake whitefish (Coregonus clupeaformis) was an important member of the native fish community and a valued commercial species in Lake Ontario. Lake whitefish were common in U.S. waters of the lake until 1965 and very abundant in Canadian waters through the early 1970s, although their numbers declined shortly thereafter. During 1975-1985, lake whitefish stocks remained depressed throughout the lake as a result of the combined effects of degraded water quality, overfishing, and predation. Rainbow smelt (Osmerus mordax) probably preyed on whitefish fry, and sea lamprey (Petromyzon marinus) preyed on adults. During 1985-1987, lake …
Changes In Lake Whitefish Diet In Lake Michigan, 1998-2001, Stephen A. Pothoven
Changes In Lake Whitefish Diet In Lake Michigan, 1998-2001, Stephen A. Pothoven
United States Department of Commerce: Staff Publications
Lake whitefish (Coregonus clupeaformis) were collected for diet analysis from Michigan’s waters of Lake Michigan during 1998-2001. When the benthic amphipod Diporeia spp. was available, it was an important item in the diets of small (<430 mm) and large (>430 mm) lake whitefish. In southern Lake Michigan, the most-common prey consumed in the absence of Diporeia spp. included zebra mussels (Dreissena polymorpha), gastropods, chironomids, and Mysis relicta. In northern regions of the lake, alternative prey included chironomids, isopods, Bythotrephes, and fish. Following the decline of Diporeia spp. in southeastern Lake Michigan between 1998 and 2001, their contribution …