8 results on '"Jefferson, Thomas A."'
Search Results
2. Distribution and Abundance of California (Zalophus californianus) and Steller (Eumetopias jubatus) Sea Lions in the Inshore Waters of Washington, 2013-2016.
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Jefferson, Thomas A., Smultea, Mari A., and Ward, Eric J.
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SEA lions , *STEELHEAD trout , *BODIES of water , *MARINE mammals , *NUMBERS of species , *SPRING , *AUTUMN - Abstract
Two species of sea lions occur in the inland waters of Washington State: the California sea lion (Zalophus californianus) and the Steller sea lion (Eumetopias jubatus). Both species breed elsewhere, but they typically move into Puget Sound and adjacent waters of the Salish Sea from autumn through spring. There is a need for information on their current abundance and seasonal use patterns as both species prey heavily on threatened/ endangered stocks of salmon and steelhead trout (Oncorhynchus spp.), and empirical abundance estimates of these species are lacking for inland Washington waters. From 2013 to 2016, we conducted 39,399 km of aerial surveys for marine mammals in this area, sighting 255 groups of sea lions. We used a subset of 7,841 km of effort and 165 sea lion sightings made during surveys in good sighting conditions to estimate in-water abundance using line-transect methods. Historical tagging data collected in Pacific Northwest waters were used to evaluate the proportions of time that each species spent on land and conducting dives, and then to develop correction factors to derive total abundance for both sea lion species, providing the first empirical abundance estimates for these waters. We estimated that between 33 and 442 California sea lions were found in Puget Sound/ Hood Canal in different seasons, with nearly 3,000 being found in the broader inland Washington waters in the peak season (spring). Steller sea lions occurred in much smaller numbers, with a peak of 219 animals in Puget Sound/Hood Canal/Strait of Juan de Fuca in autumn (and possibly as many as 600 to 700 in the entire study area). While some estimates suffer from low precision, this study demonstrates that substantial numbers of sea lions use waters of the study area throughout much of the year. Our results provide an important step toward a better understanding of these two species in the inland waters of Washington, as well as their potential effects on protected salmonid prey species. [ABSTRACT FROM AUTHOR]
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- 2023
- Full Text
- View/download PDF
3. Marine mammals of the United States Exploring Expedition, 1838–1842: history and taxonomy.
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Jefferson, Thomas A.
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GEOGRAPHICAL discoveries , *MARINE mammals , *MARINE biology , *GOVERNMENT publications , *TAXONOMY , *CETACEA - Abstract
The United States Exploring Expedition of 1838–1842, in some ways, represents the beginning of American marine mammal biology. The expedition returned home with information on at least twelve marine mammal specimens (mostly small cetaceans or pinnipeds), seven of which were considered new species at the time. Commanded by Lieutenant Charles Wilkes, the expedition covered over 80,000 miles, surveyed new waters and lands, and brought back thousands of scientific specimens. Official publications of the expedition by Titian Peale and John Cassin cover the birds and mammals collected. The squadron's publications, and the journals of its officers and scientists also contain a good deal of information about sightings of marine mammals. Of particular interest were whaling operations and grounds, and the expedition did much to help expand the whaling prospects of the United States around the globe, with a focus on the South Pacific islands. Though largely forgotten today, the "U. S. Ex. Ex." played an important early role in establishing American influence in marine mammal biology and global whaling operations. [ABSTRACT FROM AUTHOR]
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- 2023
- Full Text
- View/download PDF
4. Geographic range size, water temperature, and extrinsic threats predict the extinction risk in global cetaceans.
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Chen, Chuanwu, Jefferson, Thomas A., Chen, Bingyao, and Wang, Yanping
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ENDANGERED species , *CETACEA , *WATER temperature , *BYCATCHES , *TOOTHED whales , *SEXUAL cycle , *OCEAN temperature - Abstract
Despite the fact that cetaceans provide significant ecological contributions to the health and stability of aquatic ecosystems, many are highly endangered with nearly one‐third of species assessed as threatened with extinction. Nevertheless, to date, few studies have explicitly examined the patterns and processes of extinction risk and threats for this taxon, and even less between the two subclades (Mysticeti and Odontoceti). To fill this gap, we compiled a dataset of six intrinsic traits (active region, geographic range size, body weight, diving depth, school size, and reproductive cycle), six environmental factors relating to sea surface temperature and chlorophyll concentration, and two human‐related threat indices that are commonly recognized for cetaceans. We then employed phylogenetic generalized least squares models and model selection to identify the key predictors of extinction risk in all cetaceans, as well as in the two subclades. We found that geographic range size, sea surface temperature, and human threat index were the most important predictors of extinction risk in all cetaceans and in odontocetes. Interestingly, maximum body weight was positively associated with the extinction risk in mysticetes, but negatively related to that for odontocetes. By linking seven major threat types to extinction risk, we further revealed that fisheries bycatch was the most common threat, yet the impacts of certain threats could be overestimated when considering all species rather than just threatened ones. Overall, we suggest that conservation efforts should focus on small‐ranged cetaceans and species living in warmer waters or under strong anthropogenic pressures. Moreover, further studies should consider the threatened status of species when superimposing risk maps and quantifying risk severity. Finally, we emphasize that mysticetes and odontocetes should be conserved with different strategies, because their extinction risk patterns and major threat types are considerably different. For instance, large‐bodied mysticetes and small‐ranged odontocetes require special conservation priority. [ABSTRACT FROM AUTHOR]
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- 2022
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5. MARINE MAMMAL OCCURRENCE, DISTRIBUTION, AND BEHAVIOR IN THE INLAND WATERS OF WASHINGTON FROM AERIAL SURVEYS, 2013–2016.
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Smultea, Mari A, Jefferson, Thomas A, and Lane, Rebekah S
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SEA lions , *AERIAL surveys , *HARBOR seal , *HARBOR porpoise , *MARINE mammals , *WHALES - Abstract
The inland waters of Washington State are inhabited regularly by 10 species of marine mammals. Updated and comprehensive information regarding marine mammal occurrence, distribution, and behavior in the area is critical when addressing local anthropogenic impact, management, and conservation concerns. We conducted a total of 16,198 km of observation effort during systematic line-transect surveys from a high-wing, twin-engine airplane throughout Puget Sound in all 4 seasons during 2013 to 2016, and in the Strait of Juan de Fuca and San Juan Islands area during summer 2014 and spring 2015. Ten marine mammal species were confirmed across 5772 groups of an estimated 10,673 individuals sighted, including some seasonal patterns of occurrence. The most commonly sighted species in terms of individuals were Harbor Seals (n = 8012), Harbor Porpoises (n = 2168), California Sea Lions (n = 238) and Steller Sea Lions (n = 77). The most common behavior states documented across species among the total 5670 groups were rest (73%) and medium travel (16%); probable foraging was observed among 13 groups (0.2%) and included Gray Whale foraging pits in tidal mudflats. Potential behavioral reactions to the aircraft were rare (0.3% of total individuals), primarily by Harbor Seals and Harbor Porpoises. Results of these surveys represent the most comprehensive up-to-date information available on marine mammal occurrence, distribution, and behavior across seasons in the Puget Sound region. [ABSTRACT FROM AUTHOR]
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- 2022
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6. PRAISE FOR ALGERNON SIDNEY FROM THE FOUNDING ERA.
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Jefferson, Thomas, Adams, John, Quincy Jr., Josiah, Franklin, Benjamin, Warren, Mercy Otis, Campbell, Thomas, Winthrop, Robert C., and Thomson, John
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PRAISE , *RECOMMENDED books - Abstract
The article focuses on highlighting the profound admiration and reverence for Algernon Sidney's works among influential figures like Thomas Jefferson, John Adams, Josiah Quincy Jr., and Benjamin Franklin, who regarded Sidney's writings as essential for understanding republican principles, governance, and the spirit of liberty, advocating for their inclusion in educational curricula and literary canons.
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- 2024
7. Distribution and Abundance of Marine Mammals in the Estuarine Waters of the Piscataqua River, Maine, USA.
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Zoidis, Ann M., Olson, Paula A., Jefferson, Thomas A., Johnson, Niccolas C., Soucier, Christian P., and Bassi, Jessica H.
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GRAY seal , *HARBOR seal , *MINKE whale , *HARBOR porpoise , *MARINE mammals , *HYDROGRAPHIC surveying - Abstract
The estuaries and tidal rivers of the Gulf of Maine have rarely been surveyed systematically for marine mammals. We report here on three years of survey data, 2017 to 2019. This study employed a shipboard visual line-transect methodology study design, collecting data on marine mammals in the lower Piscataqua River, which is confluent with the Gulf of Maine. Marine mammal species observed most often were harbor seals (Phoca vitulina) and gray seals (Halichoerus grypus), with a resulting in-water density estimate of 1.02 seals/km2 and an abundance estimate of seven harbor seals and one gray seal (CV = 19.3%) in the survey area. Seals were present in all months of the year. No live pups were detected. Harbor porpoises (Phocoena pho-coena) and minke whales (Balaenoptera acuto-rostrata) were also observed, but the sightings (6 harbor porpoises; 7 minke whales) did not yield enough data to estimate density or abundance. The minke whales were present during August and September 2018, concurrent with an influx of Atlantic menhaden (Brevoortia tyrannus), a prey species. The consistent albeit relatively low marine mammal species sightings and abundances suggest that the lower Piscataqua River is used regularly by a relatively small number of harbor and gray seals, although not for pupping, and occasionally by harbor porpoises and by foraging minke whales. This is the first study of its kind in an estuarine environment in the Gulf of Maine. [ABSTRACT FROM AUTHOR]
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- 2022
- Full Text
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8. Development and Validation of the Transcendent Beliefs Scale (TBS): A 12-Item Assessment of Self-Transcendent States.
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Stapleton, Peta, Church, Dawson, Newberg, Andrew, and Jefferson, Thomas
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NARCISSISM , *EXPLORATORY factor analysis , *PERSONALITY , *PHENOMENOLOGY , *FACTOR structure , *TEST validity - Abstract
Objective: The purpose of this study was to develop and validate the Transcendent Beliefs Scale (TBS). We defined transcendent experiences as an experience of unity with others and the whole of existence, which is associated with behavioural, cognitive, emotional, and transcendental factors. Our aim was to develop a very brief instrument that accurately reflected the phenomenology of transcendent states. Method: The factor structure, validity, and reliability of the TBS were assessed across a sample of university students and energy therapy practitioners (N = 305). Results: With respect to convergent validity, we found that transcendent experiences were positively correlated with daily spiritual experiences, trait hope, and meaning in life. Discriminant validity was demonstrated through a negative weak relationship to narcissistic personality traits. Exploratory factor analysis reduced the scale to 12 items and a two-factor model was found to fit the data. Conclusion: The results indicate that the TBS is a valid and reliable scale to measure transcendent beliefs in the general population. It is suitable for research projects in which a brief measure of transcendence is required. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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