Inferring causal factors for a declining population of bottlenose dolphins via temporal symmetry capture-recapture modeling

Rohan J. C. Currey, Stephen M. Dawson, Karsten Schneider, David Lusseau, Oliver J. Boisseau, Patti A. Haase, Elisabeth Slooten

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

We applied temporal symmetry capture-recapture (TSCR) models to assess the strength of evidence for factors potentially responsible for population decline in bottlenose dolphins (Tursiops truncatus) in Doubtful Sound, New Zealand from 1995 to 2008. Model selection was conducted to estimate recruitment and population growth rates. There were similar levels of support for three different models, each reflecting distinct trends in recruitment. Modeling yielded low overall estimates of recruitment (0.0249, 95% CI: 0.0174-0.0324) and population growth rate (0.9642, 95% CI: 0.9546-0.9737). The TSCR rate of population decline was consistent with an estimate derived from trends in abundance (lambda = 0.9632, 95% CI: 0.9599-0.9665). The TSCR model selection confirmed the influence of a decline in the survival of calves (<1 yr old) since 2002 for population trends. However, TSCR population growth rates did not exceed 1 in any year between 1995 and 2008, indicating the population was declining prior to 2002. A separate reduction in juvenile survival (1-3 yr old) prior to 2002 was identified as a likely contributing factor in the population decline. Thus, TSCR modeling indicated the potential cause of the population decline in Doubtful Sound: cumulative impacts on individuals <3 yr old resulting in a reduced recruitment.

Original languageEnglish
Pages (from-to)554-566
Number of pages13
JournalMarine Mammal Science
Volume27
Issue number3
Early online date30 Sep 2010
DOIs
Publication statusPublished - Jul 2011

Keywords

  • cumulative impacts
  • demography
  • Fiordland
  • information theory
  • population decline
  • reverse-time capture-mark-recapture
  • Tursiops truncatus
  • New-Zealand
  • Doubtful Sound
  • conservation biology
  • Tursiops-Truncatus
  • marked animals
  • Dusky Sound
  • abundance
  • communities
  • survival
  • habitat

Cite this

Inferring causal factors for a declining population of bottlenose dolphins via temporal symmetry capture-recapture modeling. / Currey, Rohan J. C.; Dawson, Stephen M.; Schneider, Karsten; Lusseau, David; Boisseau, Oliver J.; Haase, Patti A.; Slooten, Elisabeth.

In: Marine Mammal Science, Vol. 27, No. 3, 07.2011, p. 554-566.

Research output: Contribution to journalArticle

Currey, Rohan J. C. ; Dawson, Stephen M. ; Schneider, Karsten ; Lusseau, David ; Boisseau, Oliver J. ; Haase, Patti A. ; Slooten, Elisabeth. / Inferring causal factors for a declining population of bottlenose dolphins via temporal symmetry capture-recapture modeling. In: Marine Mammal Science. 2011 ; Vol. 27, No. 3. pp. 554-566.
@article{559a2459186b4b5785aec843146dc457,
title = "Inferring causal factors for a declining population of bottlenose dolphins via temporal symmetry capture-recapture modeling",
abstract = "We applied temporal symmetry capture-recapture (TSCR) models to assess the strength of evidence for factors potentially responsible for population decline in bottlenose dolphins (Tursiops truncatus) in Doubtful Sound, New Zealand from 1995 to 2008. Model selection was conducted to estimate recruitment and population growth rates. There were similar levels of support for three different models, each reflecting distinct trends in recruitment. Modeling yielded low overall estimates of recruitment (0.0249, 95{\%} CI: 0.0174-0.0324) and population growth rate (0.9642, 95{\%} CI: 0.9546-0.9737). The TSCR rate of population decline was consistent with an estimate derived from trends in abundance (lambda = 0.9632, 95{\%} CI: 0.9599-0.9665). The TSCR model selection confirmed the influence of a decline in the survival of calves (<1 yr old) since 2002 for population trends. However, TSCR population growth rates did not exceed 1 in any year between 1995 and 2008, indicating the population was declining prior to 2002. A separate reduction in juvenile survival (1-3 yr old) prior to 2002 was identified as a likely contributing factor in the population decline. Thus, TSCR modeling indicated the potential cause of the population decline in Doubtful Sound: cumulative impacts on individuals <3 yr old resulting in a reduced recruitment.",
keywords = "cumulative impacts, demography, Fiordland, information theory, population decline, reverse-time capture-mark-recapture, Tursiops truncatus, New-Zealand, Doubtful Sound, conservation biology, Tursiops-Truncatus, marked animals, Dusky Sound, abundance, communities, survival, habitat",
author = "Currey, {Rohan J. C.} and Dawson, {Stephen M.} and Karsten Schneider and David Lusseau and Boisseau, {Oliver J.} and Haase, {Patti A.} and Elisabeth Slooten",
year = "2011",
month = "7",
doi = "10.1111/j.1748-7692.2010.00417.x",
language = "English",
volume = "27",
pages = "554--566",
journal = "Marine Mammal Science",
issn = "0824-0469",
publisher = "Wiley-Blackwell",
number = "3",

}

TY - JOUR

T1 - Inferring causal factors for a declining population of bottlenose dolphins via temporal symmetry capture-recapture modeling

AU - Currey, Rohan J. C.

AU - Dawson, Stephen M.

AU - Schneider, Karsten

AU - Lusseau, David

AU - Boisseau, Oliver J.

AU - Haase, Patti A.

AU - Slooten, Elisabeth

PY - 2011/7

Y1 - 2011/7

N2 - We applied temporal symmetry capture-recapture (TSCR) models to assess the strength of evidence for factors potentially responsible for population decline in bottlenose dolphins (Tursiops truncatus) in Doubtful Sound, New Zealand from 1995 to 2008. Model selection was conducted to estimate recruitment and population growth rates. There were similar levels of support for three different models, each reflecting distinct trends in recruitment. Modeling yielded low overall estimates of recruitment (0.0249, 95% CI: 0.0174-0.0324) and population growth rate (0.9642, 95% CI: 0.9546-0.9737). The TSCR rate of population decline was consistent with an estimate derived from trends in abundance (lambda = 0.9632, 95% CI: 0.9599-0.9665). The TSCR model selection confirmed the influence of a decline in the survival of calves (<1 yr old) since 2002 for population trends. However, TSCR population growth rates did not exceed 1 in any year between 1995 and 2008, indicating the population was declining prior to 2002. A separate reduction in juvenile survival (1-3 yr old) prior to 2002 was identified as a likely contributing factor in the population decline. Thus, TSCR modeling indicated the potential cause of the population decline in Doubtful Sound: cumulative impacts on individuals <3 yr old resulting in a reduced recruitment.

AB - We applied temporal symmetry capture-recapture (TSCR) models to assess the strength of evidence for factors potentially responsible for population decline in bottlenose dolphins (Tursiops truncatus) in Doubtful Sound, New Zealand from 1995 to 2008. Model selection was conducted to estimate recruitment and population growth rates. There were similar levels of support for three different models, each reflecting distinct trends in recruitment. Modeling yielded low overall estimates of recruitment (0.0249, 95% CI: 0.0174-0.0324) and population growth rate (0.9642, 95% CI: 0.9546-0.9737). The TSCR rate of population decline was consistent with an estimate derived from trends in abundance (lambda = 0.9632, 95% CI: 0.9599-0.9665). The TSCR model selection confirmed the influence of a decline in the survival of calves (<1 yr old) since 2002 for population trends. However, TSCR population growth rates did not exceed 1 in any year between 1995 and 2008, indicating the population was declining prior to 2002. A separate reduction in juvenile survival (1-3 yr old) prior to 2002 was identified as a likely contributing factor in the population decline. Thus, TSCR modeling indicated the potential cause of the population decline in Doubtful Sound: cumulative impacts on individuals <3 yr old resulting in a reduced recruitment.

KW - cumulative impacts

KW - demography

KW - Fiordland

KW - information theory

KW - population decline

KW - reverse-time capture-mark-recapture

KW - Tursiops truncatus

KW - New-Zealand

KW - Doubtful Sound

KW - conservation biology

KW - Tursiops-Truncatus

KW - marked animals

KW - Dusky Sound

KW - abundance

KW - communities

KW - survival

KW - habitat

U2 - 10.1111/j.1748-7692.2010.00417.x

DO - 10.1111/j.1748-7692.2010.00417.x

M3 - Article

VL - 27

SP - 554

EP - 566

JO - Marine Mammal Science

JF - Marine Mammal Science

SN - 0824-0469

IS - 3

ER -