Gray whale visual sightings from shore 2014-2015

Regina Guazzo

doi:10.15468/ucgwz4

Gray whale visual sightings from shore 2014-2015

Citation

Guazzo, R. 2018. Gray whale visual sightings from shore 2014-2015. Data downloaded from OBIS-SEAMAP (http://seamap.env.duke.edu/dataset/1862) on yyyy-mm-dd. https://doi.org/10.15468/ucgwz4 accessed via GBIF.org on 2023-06-10.

Description

Original provider: Regina A. Guazzo, Scripps Institution of Oceanography Dataset credits: National Oceanic and Atmospheric Administration, Southwest Fisheries Science Center Abstract: During the eastern North Pacific gray whale 2014–2015 southbound migration, acoustic call recordings, infrared blow detections, and visual sightings were combined to estimate cue rates, needed to convert detections into abundance. The gray whale M3 acoustic call rate was 2.3–24 calls/whale/day with an average of 7.5 calls/whale/day over the entire migration (southbound and northbound) and showed a positive trend from 30 December–13 February. The infrared camera blow rate averaged 49 blows/whale/hour over 5–8 January. With a call rate model, we estimated that 4,340 gray whales migrated south before visual observations began on 30 December, which is 2,829 more gray whales than used in the visual abundance estimate. This finding highlights the usefulness of cue rates to increase precision in abundance estimates. We suggest that visual observers increase their survey effort to all of December to verify gray whale abundance corrections. Probability of detection of a whale blow by the infrared camera was the same at night as during the day. However, probability of detection decreased beyond 2.1 km offshore, whereas visual sightings revealed consistent whale densities up to 3 km offshore. We suggest that future infrared camera surveys use multiple cameras optimized for different ranges offshore. Supplemental information: Visual Observation Location: 36 26' 23.61" N 121 55' 20.5" W The sheet labeled "Effort" contains start and end times for observations in both UTC and PST time zones. B indicates the observations were beginning and E indicates the observations were ending. times are in Matlab's datenum format: Days since January 0, 0000 The sheet labeled "Modeled Abundance" contains the estimated number of whales that passed each day. Date is the Julian Date in Matlab's datenum format: Days since January 0, 0000. The estimated number of whales each day are given as a probability distribution. Median and the 95% highest posterior density interval are reported. Methods are described by Durban et al. 2015. The original datasheet is included in the downloadable zipped file.

Purpose

Not available

Sampling Description

Study Extent

NA

Sampling

NA

Method steps

NA

Additional info

marine, harvested by iOBIS

Taxonomic Coverages

Scientific names are based on the Integrated Taxonomic Information System (ITIS).

Eschrichtius robustus
common name: Gray Whale rank: species

Geographic Coverages

Granite Canyon,Pacific,Monterey Bay National Marine Sanctuary,California

Bibliographic Citations

Contacts

Regina Guazzo
originator
position: Primary contact
Naval Information Warfare Center Pacific
email: rguazzo@ucsd.edu

OBIS-SEAMAP
metadata author
Marine Geospatial Ecology Lab, Duke University
A328 LSRC building
Durham
27708
NC
US
email: seamap-contact@duke.edu
homepage: http://seamap.env.duke.edu

OBIS-SEAMAP
distributor
Marine Geospatial Ecology Lab, Duke University
A328 LSRC building
Durham
27708
NC
US
email: seamap-contact@duke.edu
homepage: http://seamap.env.duke.edu

Regina Guazzo
owner
position: Primary contact
Naval Information Warfare Center Pacific
email: rguazzo@ucsd.edu

Regina Guazzo
administrative point of contact
position: Primary contact
Naval Information Warfare Center Pacific
email: rguazzo@ucsd.edu