Effective strip widths for ship-based line-transect surveys of cetaceans
Advanced Search
Select up to three search categories and corresponding keywords using the fields to the right. Refer to the Help section for more detailed instructions.

Search our Collections & Repository

All these words:

For very narrow results

This exact word or phrase:

When looking for a specific result

Any of these words:

Best used for discovery & interchangable words

None of these words:

Recommended to be used in conjunction with other fields



Publication Date Range:


Document Data


Document Type:






Clear All

Query Builder

Query box

Clear All

For additional assistance using the Custom Query please check out our Help Page


Effective strip widths for ship-based line-transect surveys of cetaceans

Filetype[PDF-1.00 MB]


  • Description:
    "Effective strip width is a key parameter in estimating abundance and density from line- transect surveys. Here we estimate effective strip widths for 58 categories (genera, species, subspecies, stocks, or other groups) of cetaceans based on 13,500 sightings from 32 line-transect surveys conducted in the eastern Pacific Ocean by the Southwest Fisheries Science Center from 1991 to 2008. Generalized linear models (GLMs) are used to first identify factors that are important in determining the perpendicular sigh ting distances using stepwise model selection based on AIC. Six species groups of similar taxa are created and modeled separately. Important factors for most species groups include Beaufort sea state, swell height, visibility, group size, species, and a survey-specific categorical variable (Cruise#). Interactions between species and the other factors generally do not improve GLM fits, indicating that the effects of those factors are relatively consistent for species within a species group. Factors selected for the best-fit GLMs are included as potential covariates in a line-transect model fit to a subset of the same data, again using stepwise model selection based on AIC. The best-fit line-transect models do not include Cruise# and are generally simpler than the GLMs, likely because distant sightings were eliminated by truncation. Species-specific differences in ESW are seen within the species groups indicating that species of cetacean do differ in the distances at which they can be detected, even after accounting for the effects of group size and other covariates that affect sighting distances. Results from this analysis of multiple surveys can be used to improve estimates of effective strip widths for any survey using the same methods and similar vessels. This is especially true for seldom-seen species whose abundance is difficult to estimate from a single survey"--Abstract.
  • Content Notes:
    Jay Barlow, Lisa T. Ballance, and Karin A. Forney.

    "November 2011."

    System requirements: Adobe Acrobat Reader.

    Includes bibliographical references (page 14).

  • Document Type:
  • Place as Subject:
  • Rights Information:
    Public Domain
  • Compliance:
  • Main Document Checksum:
  • File Type:

Supporting Files

  • No Additional Files

More +

You May Also Like

Checkout today's featured content at repository.library.noaa.gov

Version 3.21