Skip to content

Research at St Andrews

Methods for investigating measurement error in cetacean line-transect surveys

Research output: Contribution to journalArticle

Author(s)

Robert Williams, R Leaper, AN Zerbini, Philip Steven Hammond

School/Research organisations

Abstract

Line-transect estimates of abundance generally assume that distances and angles to animals are measured without error. Biased distance measurements will lead to corresponding bias in abundance estimates. Efforts to address this have been made, but measuring distance to cetaceans at sea remains problematic. Four distance-estimation experiments were conducted to explore relationships between estimated and measured distance, Heteroscedasticity was found in all four cases. Preliminary evidence suggested that an observer differed in the ability to judge distance to fixed, continuously-visible cues and ephemeral, cetacean cues, which calls into the question the common practice of using marker buoys as cetacean proxies in distance-estimation experiments. Two studies found visual estimates to be positively biased, and two studies found reticule measurements to be negatively biased. Suitable correction factors were developed to address systematic bias from visual estimates, but these varied widely among observers and were sometimes non-linear. Errors in three studies showed positive skew, suggesting that ranges were overestimated to a larger degree than they were underestimated. if reticule and photogrammetric measurements yield log-normally distributed errors generally, then a least-squares regression will always overstimate the correction factor, underestimate range, and overestimate abundance. Photogrammetric methods to measure range to cetaceans performed well, and their use is encouraged. When measurements cannot be made to all sightings, however, it is recommended that experiements be conducted that generate sufficient sample size (of the target species, across typical survey conditions, and beyond the maximum range that most estimates will be made during the survey) to assess error distributions, examine evidence for non-linearity, and to consider inter-observer differences. Distance experiments, and training on survey protocols, and be conducted using ships of opportunity prior to the beginning of a dedicated survey, which would improve observer efficiency while reducing the costs of dedicated vessel time.

Close

Details

Original languageEnglish
Pages (from-to)313-320
Number of pages8
JournalJournal of the Marine Biological Association of the United Kingdom
Volume87
Issue number1
DOIs
Publication statusPublished - 26 Feb 2007

    Research areas

  • Abundance, Distance

Discover related content
Find related publications, people, projects and more using interactive charts.

View graph of relations

Related by author

  1. Decline in abundance and apparent survival rates of fin whales (Balaenoptera physalus) in the northern Gulf of St. Lawrence

    Schleimer, A., Ramp, C., Delarue, J., Carpentier, A., Bérubé, M., Palsbøl, P. J., Sears, R. & Hammond, P. S., Apr 2019, In : Ecology and Evolution. 9, 7, p. 4231-4244 14 p.

    Research output: Contribution to journalArticle

  2. Variations in age- and sex-specific survival rates help explain population trend in a discrete marine mammal population

    Arso Civil, M., Cheney, B., Quick, N. J., Islas-Villanueva, V., Graves, J. A., Janik, V. M., Thompson, P. M. & Hammond, P. S., Jan 2019, In : Ecology and Evolution. 9, 1, p. 533-544 12 p.

    Research output: Contribution to journalArticle

  3. Phylogenetic relationships in southern African Bryde's whales inferred from mitochondrial DNA: further support for subspecies delineation between the two allopatric populations

    Penry, G. S., Hammond, P. S., Cockcroft, V. G., Best, P. B., Thornton, M. & Graves, J. A., Dec 2018, In : Conservation Genetics. 19, 6, p. 1349-1365

    Research output: Contribution to journalArticle

  4. Assessing cetacean surveys throughout the Mediterranean Sea: a gap analysis in environmental space

    Mannocci, L., Roberts, J. J., Halpin, P. N., Authier, M., Boisseau, O., Bradai, M. N., Cañadas, A., Chicote, C., David, L., Di-Méglio, N., Fortuna, C. M., Frantzis, A., Gazo, M., Genov, T., Hammond, P. S., Holcer, D., Kaschner, K., Kerem, D., Lauriano, G., Lewis, T. & 7 othersNotarbartolo di Sciara, G., Panigada, S., Raga, J. A., Scheinin, A., Ridoux, V., Vella, A. & Vella, J., 15 Feb 2018, In : Scientific Reports. 8, 14 p., 3126.

    Research output: Contribution to journalArticle

  5. Cetacean rapid assessment: an approach to fill knowledge gaps and target conservation across large data deficient areas

    Braulik, G. T., Kasuga, M., Wittich, A., Kiszka, J. J., MacAulay, J., Gillespie, D., Gordon, J., Said, S. S. & Hammond, P. S., Feb 2018, In : Aquatic Conservation: Marine and Freshwater Ecosystems. 28, 1, p. 216-230

    Research output: Contribution to journalArticle

Related by journal

  1. Organizing, supporting and linking the world marine biodiversity research community

    Costello, M. J., Archambault, P., Chavanich, S., Miloslavich, P., Paterson, D. M., Phang, S-M., Sousa Pinto, I., Pierrot-Bults, A., Song, S., Soto, E. H., Stenseth, N. C., Molodtsova, T. N. & Thorndyke, M., 10 Feb 2015, In : Journal of the Marine Biological Association of the United Kingdom.

    Research output: Contribution to journalEditorial

  2. Killer whale (Orcinus orca) occurrence and predation in the Bahamas

    Dunn, C. A. & Claridge, D., 2013, In : Journal of the Marine Biological Association of the United Kingdom. 5 p.

    Research output: Contribution to journalArticle

Related by journal

  1. Journal of the Marine Biological Association of the United Kingdom (Journal)

    Claire Lacey (Member of editorial board)
    Jan 2019

    Activity: Publication peer-review and editorial work typesPeer review of manuscripts

  2. Journal of the Marine Biological Association of the United Kingdom (Journal)

    Monica Arso Civil (Reviewer)
    5 May 2017 → …

    Activity: Publication peer-review and editorial work typesPeer review of manuscripts

ID: 353830