Muhling B.A.,University of Miami |
Reglero P.,Spanish Institute of Oceanography |
Ciannelli L.,Oregon State University |
Alvarez-Berastegui D.,Balearic Islands Coastal Observing and Forecasting System |
And 3 more authors.
Marine Ecology Progress Series | Year: 2013
Despite being well adapted for feeding in cold water on their North Atlantic feeding grounds, Atlantic bluefin tuna undertake long migrations to reach warm, low productivity spawning grounds in the Gulf of Mexico and Mediterranean Sea. Environmental conditions within spawning areas have been presumed to benefit larval survival, through appropriate feeding conditions, and enhanced larval retention and growth rates. However, field collections and studies to explore the potential mechanisms are rare. In this study, a comparison of the environmental characteristics of both spawning sites was completed using standardized environmental data and modeling methods. Predictive models of larval occurrence were constructed using historical larval collections, and environmental variables from both in situ and remotely sensed sources. Results showed that larvae on both spawning grounds were most likely to be found in warm (23 to 28°C), low chlorophyll areas with moderate current velocities and favorable regional retention conditions. In the Gulf of Mexico, larvae were located in offshore waters outside of the Loop Current and warm eddies, while in the western Mediterranean, larval occurrences were associated with the confluence of inflowing Atlantic waters and saltier resident surface waters. Although our results suggested common themes within preferred spawning grounds on both sides of the Atlantic Ocean, the ecological processes governing larval survival and eventual recruitment are yet to be fully understood. © Inter-Research 2013. Source
Muhling B.A.,National Oceanic and Atmospheric Administration |
Lamkin J.T.,National Oceanic and Atmospheric Administration |
Roffer M.A.,Roffers Ocean Fishing Forecasting Service Inc.
Fisheries Oceanography | Year: 2010
Although bluefin tuna are found throughout the Atlantic Ocean, spawning in the western Atlantic has been recorded predominantly in the Gulf of Mexico (GOM) in spring. Larval bluefin tuna abundances from the northern GOM are formulated into an index used to tune the adult stock assessment, and the variability of this index is currently high. This study investigated whether some of the variability in larval bluefin tuna abundances was related to environmental conditions, by defining associations between larval bluefin tuna catch locations, and a suite of environmental variables. We hypothesized that certain habitat types, as defined by environmental variables, would be more likely to contain bluefin tuna larvae. Favorable habitat for bluefin tuna larvae was defined using a classification tree approach. Habitat within the Loop Current was generally less favorable, as were warm-core rings, and cooler waters on the continental shelf. The location and size of favorable habitat was highly variable among years, which was reflected in the locations of larval bluefin tuna catches. The model successfully placed bluefin tuna larvae in favorable habitat with nearly 90% accuracy, but many negative stations were also located within theoretically favorable habitat. The probability of collecting larval bluefin tuna in favorable habitat was nearly twice the probability of collecting bluefin tuna larvae across all habitats (35.5 versus 21.0%). This model is a useful addition to knowledge of larval bluefin tuna distributions; however, the incorporation of variables describing finer-scale features, such as thermal fronts, may significantly improve the model's predictive power. © 2010 Blackwell Publishing Ltd. Source
Edwards E.F.,National Oceanic and Atmospheric Administration |
Hall C.,Roffers Ocean Fishing Forecasting Service Inc. |
Moore T.J.,National Oceanic and Atmospheric Administration |
Sheredy C.,Amec Foster Wheeler |
Redfern J.V.,National Oceanic and Atmospheric Administration
Mammal Review | Year: 2015
The global distribution of fin whales Balaenoptera physalus is not fully understood. Existing maps can be divided into two conflicting categories: one showing a continuous global distribution and another showing an equatorial hiatus (gap in the global distribution) between approximately 20°N and 20°S. Questions also remain about the seasonal distribution of fin whales. To explore the suggested equatorial hiatus and seasonal distribution patterns, we synthesised information on fin whale distribution in the post-whaling era (1980-2012) from published literature, publicly available reports and studies conducted by various organisations. We created four seasonally stratified maps showing line-transect density estimates, line-transect survey effort, acoustic detections, and sightings. An equatorial hiatus in the global distribution of fin whales during the post-whaling era is supported by numerous line-transect surveys and by the rarity of equatorial acoustic detections and sightings, and corroborated by whaling era reports, morphological analyses, and genetic analyses. Our synthesis of post-whaling era data is consistent with results from other studies indicating that fin whales are more abundant at higher latitudes during warmer months and more abundant at lower latitudes (although these latitudes are still greater than 20°) during colder months. However, our synthesis and results from other studies also indicate that some fin whales in both hemispheres remain in higher latitudes (50°-60° north or south) during colder months and in lower latitudes (to approximately 20°-30° north or south) during warmer months, indicating that seasonal fin whale movements differ from the seasonal migrations of blue whales Balaenoptera musculus and humpback whales Megaptera novaeangliae. Our maps of global fin whale distribution provide a comprehensive picture of current knowledge and highlight important geographical and temporal data gaps. Surveys should be conducted within the identified data gaps in order to increase fine-scale spatial and temporal knowledge of distribution patterns, improve fin whale taxonomy, and identify areas of elevated fin whale densities that may require management of threats, such as ship strikes. © 2015 The Mammal Society and John Wiley & Sons Ltd. Source
Muhling B.A.,University of Miami |
Lamkin J.T.,National Oceanic and Atmospheric Administration |
Quattro J.M.,University of South Carolina |
Smith R.H.,National Oceanic and Atmospheric Administration |
And 4 more authors.
Bulletin of Marine Science | Year: 2011
Atlantic bluefin tuna, Thunnus thynnus (Linnaeus, 1758), are highly migratory and capable of traversing large distances throughout the North Atlantic Ocean. However, the majority of spawning activity has only been reported from the Mediterranean Sea and Gulf of Mexico. In early April 2009, low numbers of very small larval bluefin tuna were collected within and south of the Yucatan Channel, and along the western boundary of the Loop Current, northeast of Campeche Bank. In situ current velocity measurements showed that these larvae were collected in moderate to strong northward flow regimes, suggesting that they were spawned outside of the Gulf of Mexico. Here we describe the location and oceanographic environment of these larval bluefin tuna collections, and compare the 2009 data with some historical collections in the area. © 2011 Rosenstiel School of Marine and Atmospheric Science. Source
Muller-Karger F.,University of South Florida |
Roffer M.,Roffers Ocean Fishing Forecasting Service Inc. |
Walker N.,Louisiana State University |
Oliver M.,University of Delaware |
And 5 more authors.
IEEE Geoscience and Remote Sensing Magazine | Year: 2013
Earth observing satellites represent some of the most valued components of the international Global Ocean Observing System (GOOS) and of the Global Climate Observing System (GCOS), both part of the Global Earth Observation System of Systems (GEOSS). In the United States, such satellites are a cornerstone of the Integrated Ocean Observing System (IOOS), required to carry out advanced coastal and ocean research, and to implement and sustain sensible resource management policies based on science. Satellite imagery and satellite-derived data are required for mapping vital coastal and marine resources, improving maritime domain awareness, and to better understand the complexities of land, ocean, atmosphere, ice, biological, and social interactions. These data are critical to the strategic planning of in situ observing components and are critical to improving forecasting and numerical modeling. Specifically, there are several stakeholder communities that require periodic, frequent, and sustained synoptic observations. Of particular importance are indicators of ecosystem structure (habitat and species inventories), ecosystem states (health and change) and observations about physical and biogeochemical variables to support the operational and research communities, and industry sectors including mining, fisheries, and transportation. IOOS requires a strategy to coordinate the human capacity, and fund, advance, and maintain the infrastructure that provides improved remote sensing observations and support for the nation and the globe. A partnership between the private, government, and education sectors will enhance remote sensing support and product development for critical coastal and deep-water regions based on infrared, ocean color, and microwave satellite sensors. These partnerships need to include international research, government, and industry sectors in order to facilitate open data access, understanding of calibration and algorithm strategies, and fill gaps in coverage. Such partnerships will define the types of observations required to sustain vibrant coastal economies and to improve the health of our marine and coastal ecosystems. They are required to plan, fund, launch and operate the types of satellite sensors needed in the very near future to maintain continuity of observations. © 2013 IEEE. Source