Habitat-based density estimates for cetaceans in the California Current Ecosystem based on 1991–2018 survey data
Abstract
Habitat models, or species distribution models (SDMs), have been recognized as valuable tools for estimating the density and distribution of cetaceans and assessing potential impacts from a wide range of anthropogenic activities. The 2018 California Current Ecosystem Survey (CCES) was conducted between 26 June and 4 December 2018 as a joint project of the Marine Mammal and Turtle Division (MMTD) and the Fisheries Resources Division (FRD) of NOAA’s Southwest Fisheries Science Center (SWFSC). One of the primary objectives of this line-transect survey was to collect marine mammal sighting data to support the derivation of cetacean density estimates for the California Current Ecosystem (CCE) study area. Given the heterogeneity of the 2018 survey coverage in the CCE study area (Henry et al. 2020), density estimation required model-based (rather than design-based) analytical approaches for updating population size estimates for US West Coast marine mammal stocks. This report summarizes the results of the cetacean habitat modeling effort.
The overall goal of this study was to include the 2018 survey data in the previous 1991–2014 modeling dataset in order to improve SMDs for the CCE study area. Specific objectives included:
- Generating multi-year average density surfaces for the Navy and others to use in their long-term (2–7 year) environmental planning efforts; and
- Providing updated abundance and "minimum population size (Nmin)" estimates as defined in the Guidelines for Assessing Marine Mammal Stocks (National Oceanic and Atmospheric Administration 2016).
Citation
Becker, E. A., Forney, K. A., Miller, D. L., Barlow, J., Rojas-Bracho, L., Urbán R, J., & Moore, J. E. (2022). Dynamic Habitat Models Reflect Interannual Movement of Cetaceans Within the California Current Ecosystem. Frontiers in Marine Science, 9, 829523. https://doi.org/10.3389/fmars.2022.829523
Becker, E. A., Forney, K. A., Miller, D. L., Fiedler, P. C., Barlow, J., & Moore, J. E. Habitat-based density estimates for cetaceans in the California Current Ecosystem based on 1991–2018 survey data
Download ERDAS IMAGINE img archive of models (1 MB)
| Species common name | Scientific name | Period | Mapper URL |
|---|---|---|---|
| Baird's beaked whale | Berardius bairdii | Summer & Fall | Mapper |
| Blue whale | Balaenoptera musculus | Summer & Fall | Mapper |
| Common bottlenose dolphin | Tursiops truncatus | Summer & Fall | Mapper |
| Common minke whale | Balaenoptera acutorostrata | Summer & Fall | Mapper |
| Dall's porpoise | Phocoenoides dalli | Summer & Fall | Mapper |
| Fin whale | Balaenoptera physalus | Summer & Fall | Mapper |
| Humpback whale | Megaptera novaeangliae | Summer & Fall | Mapper |
| Long-beaked common dolphin | Delphinus delphis bairdii | Summer & Fall | Mapper |
| Northern right whale dolphin | Lissodelphis borealis | Summer & Fall | Mapper |
| Pacific white-sided dolphin | Lagenorhynchus obliquidens | Summer & Fall | Mapper |
| Risso's dolphin | Grampus griseus | Summer & Fall | Mapper |
| Short-beaked common dolphin | Delphinus delphis delphis | Summer & Fall | Mapper |
| Small beaked whales | Guild | Summer & Fall | Mapper |
| Sperm whale | Physeter macrocephalus | Summer & Fall | Mapper |
| Striped dolphin | Stenella coeruleoalba | Summer & Fall | Mapper |
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ACKNOWLEDGMENTS