Aerial Surveys, Abundance, and Distribution of Beluga Whales (Delphinapterus Leucas) in Cook Inlet, Alaska, June 2016

Aerial Surveys, Abundance, and Distribution of Beluga Whales (Delphinapterus Leucas) in Cook Inlet, Alaska, June 2016
Author: Kim E. W. Shelden
Publisher:
Total Pages: 62
Release: 2017
Genre: Aerial surveys in wildlife management
ISBN:

The National Marine Fisheries Service (NMFS) has conducted aerial surveys to estimate abundance of the beluga population in Cook Inlet, Alaska, each June, July, or both from 1993 to 2012, after which biennial surveys began in 2014. The current document presents survey results and subsequent analyses yielding an abundance estimate and population trend based on data collected during June 2016. Surveys occurred May 31 - June 9, 2016 (49.2 flight hours). All surveys were flown in twin-engine, high-wing aircraft (i.e., an Aero Commander) at a target altitude of 244 m (800 ft) and speed of 185 km/hour (100 knots), consistent with NMFS' surveys of Cook Inlet conducted in previous years. Tracklines were flown 1.4 km from the shoreline, along the entire Cook Inlet coast, including islands. Additionally, sawtooth pattern tracklines were flown across the inlet in 2016. These aerial surveys effectively covered 40% of the total surface area of Cook Inlet and 100% of the coastline. In particular, most of the upper inlet, north of the East and West Foreland where beluga whales are consistently found, was surveyed seven times (out of seven attempts). Paired, independent observers searched on the coastal side of the plane, where most beluga sightings occur, while a single observer searched on the inlet side. A computer operator/data recorder periodically monitored distance from the shoreline (1.4 km) with a clinometer (angle 10°). After finding beluga groups, a series of aerial passes allowed all observers to each make independent counts of every group. In addition, whale groups were video recorded for later analysis and more precise counts in the laboratory. [doi:10.7289/V5/AFSC-PR-2017-09 (https://doi.org/10.7289/V5/AFSC-PR-2017-09)]

Detecting Changes in Population Trends for Cook Inlet Beluga Whales (Delphinapterus Leucas) Using Alternative Schedules for Aerial Surveys

Detecting Changes in Population Trends for Cook Inlet Beluga Whales (Delphinapterus Leucas) Using Alternative Schedules for Aerial Surveys
Author: Roderick C. Hobbs
Publisher:
Total Pages: 25
Release: 2013
Genre: Aerial surveys in wildlife management
ISBN:

"Measuring population trends, and detecting a change in the trend, of Cook Inlet beluga whales (CIB), Delphinapterus leucas, has a specific role in the co-management agreement that determines harvest levels, and a more general application in the management of the population. Currently, an annual aerial survey schedule has provided abundance estimates from which growth trends for this population are determined. Under the harvest co-management agreement, the measured trend over a 10-year period is used to classify the population into one of three growth categories ('high', 'intermediate', or 'low'; Appendix). The growth category, along with the average abundance over the last 5-year period, is used to determine the number of takes allowed over the next 5-year hunting period (Appendix). For a more general application, we would like to be able to detect a change in the growth rate of the population that results from a change in the underlying life history parameters such as birth interval and rates of survival and identify the year that the change occurred"--Introduction.

Detecting Changes in Population Trends for Cook Inlet Beluga Whales (Delphinapterus Leucas) Using Alternative Schedules for Aerial Surveys

Detecting Changes in Population Trends for Cook Inlet Beluga Whales (Delphinapterus Leucas) Using Alternative Schedules for Aerial Surveys
Author: Roderick C. Hobbs
Publisher:
Total Pages: 25
Release: 2013
Genre: Aerial surveys in wildlife management
ISBN:

"Measuring population trends, and detecting a change in the trend, of Cook Inlet beluga whales (CIB), Delphinapterus leucas, has a specific role in the co-management agreement that determines harvest levels, and a more general application in the management of the population. Currently, an annual aerial survey schedule has provided abundance estimates from which growth trends for this population are determined. Under the harvest co-management agreement, the measured trend over a 10-year period is used to classify the population into one of three growth categories ('high', 'intermediate', or 'low'; Appendix). The growth category, along with the average abundance over the last 5-year period, is used to determine the number of takes allowed over the next 5-year hunting period (Appendix). For a more general application, we would like to be able to detect a change in the growth rate of the population that results from a change in the underlying life history parameters such as birth interval and rates of survival and identify the year that the change occurred"--Introduction.