Progress 07/01/01 to 08/31/11
Outputs
OUTPUTS: The Gulf of Maine contains the primary feeding grounds for the northern right whale. Many movements of these animals within the Gulf of Maine on scales ranging from a few meters to hundreds of kilometers are determined by the distribution of their principle prey, Calanus finmarchicus(hereafter, Calanus), a large copepod that dominates the spring zooplankton community in the Gulf of Maine. In our proposal we outlined a model-based study of the influence of Calanus distribution and abundance on the foraging behavior and reproductive success of right whales. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Over the last 20 years, the abundance of Calanus has fluctuated by more than a factor of ten. Prior work by our group has linked these fluctuations to hydrographic changes in the Gulf of Maine driven by the North Atlantic Oscillation. Given the importance of Calanusin the diet of right whales, it is natural to ask whether fluctuations in copepod abundance influence right whale population dynamics. The variability in right whale calving rates observed each year has increased since the early 1990s. Although not simply correlated, Calanus abundance can account for over 65 percent of the variability in calving rates, provided one accounts for the whales three-year reproductive cycle (Knowlton et al., 1994). Right whales require one year for gestation and give birth to a single calf during early winter in the calving grounds off the southeast United States. The calves nurse through the summer and accompany their mothers to feeding grounds in the Gulf of Maine region. After weaning, females require at least an additional year before they can support another pregnancy. We have developed a simple model that captures the key features of this reproductive cycle. Our hypothesis is that the transitions between the three states: pregnant, nursing, and recovering, depend on feeding conditions represented by Calanus abundance. A genetic algorithm was used to find the set of transition probability functions producing the best agreement between the observed number of calves and the number predicted by the model forced with Calanus abundances. The calving rates predicted by the model capture the overall patterns very well, especially the wild fluctuations of recent years. Our model accurately predicts the dramatic increase in right whale calves observed in 2001.
Publications
- Greene, C.H., and A.J. Pershing. (2004) Climate and the conservation biology of North Atlantic right whales: the right whale at the wrong time Frontiers in Ecology and the Environment. 2: 29-34 Greene, C. H., A. J. Pershing, R. D. Kenney, and J. W. Jossi. (2003) Impact of climate variability on the recovery of endangered North Atlantic right whales. Oceanography 16:96-101
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Progress 01/01/05 to 12/31/05
Outputs
We have shifted from model development to data analysis and have completed a comparison between right whale sightings and copepod abundance. We have nearly completed the development of the database system that will support operational right whale forecasts.
Impacts
Current management plans for the northern right whale are designed to minimize whale mortality caused by entanglements in fishing gear and collisions with ships. The key to this effort is locating whales and then restricting activities around them. Our work provides a large-scale view of conditions in the Gulf of Maine that are important to whales and that may be used to locate them.
Publications
- No publications reported this period
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Progress 01/01/03 to 12/31/03
Outputs
We recently completed a system to collect, process, and distribute information on environmental factors that are likely to influence the distribution of northern right whales in the Gulf of Maine. This system gathers daily snapshots of temperature and chlorophyll distributions in the Gulf of Maine taken by NASA satellites. These data are then used to determine the reproductive and growth rates in a model of copepod dynamics (copepods are the main prey of right whales). This summer, we will be working to improve the system and develop techniques to combine the information to determine likely right whale feeding areas.
Impacts
Current management plans for the northern right whale are designed to minimize whale mortality caused by entanglements in fishing gear and collisions with ships. The key to this effort is locating whales and then restricting activities around them. Our work provides a large-scale view of conditions in the Gulf of Maine that are important to whales and that may be used to locate them.
Publications
- Greene, C.H., and A.J. Pershing. 2004. Climate and the conservation biology of North Atlantic right whales: the right whale at the wrong time? Frontiers in Ecology and the Environment. 2: 29-34.
- Greene, C. H., A. J. Pershing, R. D. Kenney, and J. W. Jossi. 2003. Impact of climate variability on the recovery of endangered North Atlantic right whales. Oceanography 16:96-101.
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Progress 01/01/02 to 12/31/02
Outputs
The Gulf of Maine contains the primary feeding grounds for the northern right whale. Many movements of these animals within the Gulf of Maine are determined by the distribution of their principle prey, Calanus finmarchicus( hereafter, Calanus), a large copepod that dominates the spring zooplankton community in the Gulf of Maine. In our proposal we outlined a model-based study of the influence of Calanus distribution and abundance on the foraging behavior and reproductive success of right whales. Phase I The variability in right whale calving rates observed each year has increased since the early 1990's. Although not simply correlated, Calanus abundance can account for over 65 percent of the variability in calving rates, provided one accounts for the whales? complex reproductive cycle. We have developed a simple model that captures the key features of this cycle. Our hypothesis is that the transitions between the three states (pregnant, nursing, and recovering) depend
on feeding conditions represented by Calanus abundance. A genetic algorithm was used to find the set of transition probability functions producing the best agreement between the observed number of calves and the number predicted by the model forced with Calanus abundances. The calving rates predicted by the model capture the overall patterns very well, especially the wild fluctuations of recent years. Assuming average Calanus abundance in 2000, our model accurately predicts the dramatic increase in right whale calves observed in 2001. Phase II The main goal of Phase II is to develop a bio-energetic model for right whales. A bio-energetic model formally represents the influence of an individual organism's foraging success on its nutritional state. The nutritional state of the animal is the amount of mass apportioned to a particular group of tissues. In each time step, the mass of the animal and how it is distributed among the tissue groups will change according to the activity of the
animal (swimming vs. resting), food intake, and basal metabolic rate, all of which are functions of the animal's state. Developing such a model for right whales is a straight forward task, and most of the important physiological relationships are available. We plan to use this model to identify optimal or near optimal migration patterns a right whale could follow in the Gulf of Maine to meet its metabolic requirements. If our model is correct, then the optimal trajectories through average seasonal Calanus distributions should include the important seasonal feeding grounds: Cape Cod Bay, Great South Channel, and Bay of Fundy. We are currently developing an advanced, interpolation procedure to produce accurate seasonal and interannual distributions of Calanus. We expect to produce the Calanus fields shortly and begin the whale modeling shortly after. Phase III The goal of Phase III is to develop a system to forecast Calanus distributions based on satellite-derived sea surface
temperatures and chlorophyll concentrations. These distributions, together with the right whale bio-energetic model would allow us to issue forecasts of areas of potential right whale feeding.
Impacts
By refining our understanding of the movements of right whales in relation to their prey, our study should allow improved management of this population.
Publications
- Greene, C. H., A. J. Pershing, R. D. Kenney, and J. W. Jossi. 2003. Impact of Climate Variability on the Recovery of Endangered North Atlantic Right Whales, submitted to Frontiers in Ecology.
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