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The AquaDocs digital repository system captures, stores, indexes, preserves, and distributes digital research material.2024-03-25T10:37:18ZStudies on Columbia River Smelt, Thaleichthys pacificus (Richardson)
http://hdl.handle.net/1834/43032
Studies on Columbia River Smelt, Thaleichthys pacificus (Richardson)
Smith, Wendell E.; Saalfeld, Robert W.
1955-02-01T00:00:00ZReport on a Workshop on Problems Related to Humpback Whales (Megaptera novaeangliae) in Hawaii
http://hdl.handle.net/1834/43031
Report on a Workshop on Problems Related to Humpback Whales (Megaptera novaeangliae) in Hawaii
Norris, Kenneth s.; Reeves, Randall R.
A small population of humpback whales, numbering between 20 and 590 animals, is the object of an increasing level of human attention in Hawaiian waters. A workshop was convened to consider the nature and extent of harassment experienced by these whales in their winter range and to discuss management and research needed to ensure that they are adequately protected there. An effort was made to define biological harassment at two levels·--one concerned with long-term reduction of biological fitness, and the other with short-term stress that may or may not affect fitness., Behavioral nuances and measurable life-history changes that may serve as indices of harassment's effects were identified,.as were the human activities implicated in harassment. A profile of the humpback population in Hawaii and its habitat was developed. It was concluded that hydrofoil transit routes and operating procedures should be adjusted.to minimize the possibility of collisions with whales... Also, operators of boats, ships, and aircraft need to be educated and advised of the potential harm they could inflict on the whales. Management recommendations included consideration of alternatives under existing legislation for a humpback park, sanctuary, or critical habitat; and a strong federal enforcement presence to monitor human/whale interaction in Hawaii.~·Research should focus primarily on whale abundance, distribution, and recruitment rate, and secondarily on social organization, normal behavior patterns, effects of harassment and levels of human activity. Papers presented at the workshop are appended to the report.
1978-04-01T00:00:00ZPreliminary Stock Structure of Coastal Bottlenose Dolphins along the Atlantic Coast of the US
http://hdl.handle.net/1834/43030
Preliminary Stock Structure of Coastal Bottlenose Dolphins along the Atlantic Coast of the US
Recent analyses have identified multiple stocks of bottlenose dolphins along the Atlantic coast from New Jersey to central Florida. Although drawing stock boundaries is confounded by the migratory pattern of the northernmost stock and by the unequal distribution of samples both spatially and temporally, results to date indicate the likelihood of a high level of structuring. In order to estimate abundance, the offshore range of the coastal morphotype of bottlenose dolphin also has been tentatively identified. That range is different north and south of Cape Hatteras; north of Cape Hatteras, evidence suggests that the coastal morphotype generally inhabits a range from the coast to 12km from shore, while south of Cape Hatteras, the range extends to 27km. Using both sets of results (latitudinal and longitudinal), management units can be defined for the purpose of evaluating the potential effects of fisheries mortality: 1. Northern Migratory Unit: In summer, this stock is found primarily from the NC/VA state line to the northern limit of the range (NJ or NY). In winter, this stock migrates out of the northern coastal areas and at least some of the animals are found off the coast of NC, where they spatially overlap with the northern and southern NC units. 2. Northern NC Unit: In summer, this unit consists of dolphins along the coast of NC from Cape Lookout to the VA/NC line and dolphins that reside in northern estuaries in this region. There is some evidence of dolphins moving between estuaries and the coast. There may also be spatial overlap between this unit and the southern NC unit in summer, at least in the estuaries near Cape Lookout. In winter, this unit occurs along the coast or estuaries of NC, where it spatially overlaps with the migratory unit and the southern NC unit. 3. Southern NC Unit: In summer, dolphins in this unit are found primarily along the coast of NC from south of Cape Lookout, NC, to Murrell's Inlet, SC. There may also be spatial overlap between this unit and the northern NC unit in summer, at least in the estuaries near Cape Lookout. In winter, these dolphins are assumed to be in the same areas, where they may spatially overlap with the migratory unit and with the Northern NC unit. 4. South Carolina Management Units: This management unit encompasses dolphins south of Murrell’s Inlet, SC, (the southern NC Unit) and the SC/GA state line. Seasonal movements that might result in spatial overlap between this stock and any others have not been defined. 5. Georgia Management Unit: This management unit encompasses dolphins in coastal and estuarine waters of Georgia. Seasonal movements that might result in spatial overlap between this stock and any others have not been defined. 6. Northern Florida Management Unit: This management unit includes dolphins from the FL/GA state line to the north end of the Indian/Banana River Lagoon system. 7. Central Florida Management Unit: This management unit begins south of the northern management unit and has an undefined southern boundary because of lack of information south of the Indian/Banana River system. However, consistent with results from areas to the north, it is precautionary to assume that this stock does not range as far south as southern Florida.
2001-06-01T00:00:00ZLandscape of the Tocantins-Araguaia Basin: challenges, dynamics, and future prospect for conservation.
http://hdl.handle.net/1834/43029
Landscape of the Tocantins-Araguaia Basin: challenges, dynamics, and future prospect for conservation.
Schmitz, Marcelo Henrique
Tropical deforestation and unsustainable policies are current challenges in the Tocantins-Araguaia River basin (TOAR), located in the heart of the Cerrado biome. In the first article, the dynamics of land use were analyzed over a period of 35 years (1985-2020). The results showed relevant anthropogenic changes driven by agricultural activities, resulting in major vegetation losses, especially in natural forests, savannas and pastures. During this period, there was an exponential growth in pastures and agriculture to the detriment of natural categories. Part of TOAR's stable areas corresponded to legally protected areas. Considering the challenges highlighted in the first article, in the second, future scenarios of land use and cover (2015-2045) were analyzed under three area demand scenarios: "Business-as-usual" (BAUS), "Conservation-based" (CONS) and "Production-based" (PROD). Analysis of future projections indicated the persistence of deforestation and fragmentation patterns, especially in the PROD scenario. The notable predicted loss in Natural Forest and Savanna, even in the conservation scenario, highlights the urgent need for proactive conservation efforts, stricter regulations, and enhanced environmental considerations in development plans. Considering the context explored and discussed in the articles presented, this study not only highlights the complexities of the past dynamics of land use in TOAR, but also points to the urgency of coordinated actions to ensure a sustainable future. The persistence of deforestation even in conservation-oriented scenarios raises questions about the effectiveness of current protection measures, emphasizing the need to re-evaluate and strengthen conservation strategies. The TOAR is at an ecological crossroads, requiring concrete and targeted efforts on the part of decision makers, researchers and the population to ensure its sustainable management and the preservation of its unique ecosystems, biodiversity and cultural heritage amidst increasing anthropogenic pressures.; O desmatamento tropical e políticas insustentáveis são desafios atuais na bacia hidrográfica do Tocantins-Araguaia (TOAR), localizada no coração do bioma Cerrado. Analisou-se a dinâmica do uso da terra em um período de 35 anos (1985-2020). Os resultados mostraram mudanças antropogênicas relevantes impulsionadas por atividades agrícolas, resultando em grandes perdas de vegetação, especialmente em florestas naturais, savanas e pastagens. Nesse período constatou-se um crescimento exponencial de pastagens e agricultura em detrimento de categorias naturais. Parte das áreas estáveis da TOAR correspondeu a áreas legalmente protegidas. Considerando os desafios destacados, analisou-se também cenários futuros de uso e cobertura da terra (2015-2045) sob três cenários de demanda de área: "Business-as-usual" (BAUS), "Conservation-based" (CONS) e "Production-based" (PROD). A análise das projeções futuras indicou a persistência de padrões de desmatamento e fragmentação, especialmente no cenário PROD. A notável perda prevista em Floresta Natural e Savana, mesmo no cenário conservacionista, evidencia a necessidade urgente de esforços proativos de conservação, regulamentações mais rigorosas e considerações ambientais aprimoradas nos planos de desenvolvimento. Considerando o contexto explorado e discutido mediante os dados obtidos, este estudo não apenas destaca as complexidades da dinâmica passada do uso da terra na TOAR, mas também aponta para a urgência de ações coordenadas para garantir um futuro sustentável. A persistência do desmatamento mesmo em cenários orientados para a conservação levanta questões sobre a eficácia das atuais medidas de proteção, enfatizando a necessidade de reavaliação e fortalecimento das estratégias de conservação. A TOAR está em uma encruzilhada ecológica, exigindo esforços concretos e direcionados por parte de tomadores de decisão, pesquisadores e população para garantir sua gestão sustentável e a preservação de seus ecossistemas únicos, biodiversidade e patrimônio cultural em meio às crescentes pressões antropogênicas.
2024-01-01T00:00:00Z