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Nautilus at risk--estimating population size and demography of Nautilus pompilius.

Dunstan A, Bradshaw CJ, Marshall J - PLoS ONE (2011)

Bottom Line: More data from wild populations are needed to design management plans which ensure Nautilus persistence.We estimated a small and dispersed population of between 844 and 4467 individuals (14.6-77.4 km(-2)) dominated by males (83:17 male:female) and comprised of few juveniles (<10%).These results provide the first Nautilid population and density estimates which are essential elements for long-term management of populations via sustainable catch models.Results from baited remote underwater video systems provide confidence for their more widespread use to assess efficiently the size and density of exploited and unexploited Nautilus populations worldwide.

View Article: PubMed Central - PubMed

Affiliation: School of Biomedical Science, University of Queensland, Brisbane, Queensland, Australia. andy.dunstan@gmail.com

ABSTRACT
The low fecundity, late maturity, long gestation and long life span of Nautilus suggest that this species is vulnerable to over-exploitation. Demand from the ornamental shell trade has contributed to their rapid decline in localized populations. More data from wild populations are needed to design management plans which ensure Nautilus persistence. We used a variety of techniques including capture-mark-recapture, baited remote underwater video systems, ultrasonic telemetry and remotely operated vehicles to estimate population size, growth rates, distribution and demographic characteristics of an unexploited Nautilus pompilius population at Osprey Reef (Coral Sea, Australia). We estimated a small and dispersed population of between 844 and 4467 individuals (14.6-77.4 km(-2)) dominated by males (83:17 male:female) and comprised of few juveniles (<10%).These results provide the first Nautilid population and density estimates which are essential elements for long-term management of populations via sustainable catch models. Results from baited remote underwater video systems provide confidence for their more widespread use to assess efficiently the size and density of exploited and unexploited Nautilus populations worldwide.

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Related in: MedlinePlus

Baited Remote Underwater Video System Nautilus attraction times.The cumulative number of Nautilus attracted to the baited trap over time is shown to produce a linear curve with a mean attraction rate of 4.03 hr−1 for the red (grey triangles) and blue/white/red (black squares) lighted traps. Traps with blue light only (black outlined circles), showed almost no attraction. Replicated results for each light combination are shown.
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pone-0016716-g005: Baited Remote Underwater Video System Nautilus attraction times.The cumulative number of Nautilus attracted to the baited trap over time is shown to produce a linear curve with a mean attraction rate of 4.03 hr−1 for the red (grey triangles) and blue/white/red (black squares) lighted traps. Traps with blue light only (black outlined circles), showed almost no attraction. Replicated results for each light combination are shown.

Mentions: Analysis of video data from video system deployments showed a negative effect on attraction when blue lights were used. These data were subsequently excluded from density and attraction analysis. Results of red light and a combination of red, white and blue light systems deployed within 200 m of each other were similar. There was a linear increase in cumulative Nautilus numbers attracted to the video system over time, with a mean attraction rate of 4.03 hr−1 (Fig. 5). From video observations we could not distinguish all individuals to sex or maturity status. We did identify only 3 juveniles out of a total of 68 Nautilus recorded.


Nautilus at risk--estimating population size and demography of Nautilus pompilius.

Dunstan A, Bradshaw CJ, Marshall J - PLoS ONE (2011)

Baited Remote Underwater Video System Nautilus attraction times.The cumulative number of Nautilus attracted to the baited trap over time is shown to produce a linear curve with a mean attraction rate of 4.03 hr−1 for the red (grey triangles) and blue/white/red (black squares) lighted traps. Traps with blue light only (black outlined circles), showed almost no attraction. Replicated results for each light combination are shown.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3037370&req=5

pone-0016716-g005: Baited Remote Underwater Video System Nautilus attraction times.The cumulative number of Nautilus attracted to the baited trap over time is shown to produce a linear curve with a mean attraction rate of 4.03 hr−1 for the red (grey triangles) and blue/white/red (black squares) lighted traps. Traps with blue light only (black outlined circles), showed almost no attraction. Replicated results for each light combination are shown.
Mentions: Analysis of video data from video system deployments showed a negative effect on attraction when blue lights were used. These data were subsequently excluded from density and attraction analysis. Results of red light and a combination of red, white and blue light systems deployed within 200 m of each other were similar. There was a linear increase in cumulative Nautilus numbers attracted to the video system over time, with a mean attraction rate of 4.03 hr−1 (Fig. 5). From video observations we could not distinguish all individuals to sex or maturity status. We did identify only 3 juveniles out of a total of 68 Nautilus recorded.

Bottom Line: More data from wild populations are needed to design management plans which ensure Nautilus persistence.We estimated a small and dispersed population of between 844 and 4467 individuals (14.6-77.4 km(-2)) dominated by males (83:17 male:female) and comprised of few juveniles (<10%).These results provide the first Nautilid population and density estimates which are essential elements for long-term management of populations via sustainable catch models.Results from baited remote underwater video systems provide confidence for their more widespread use to assess efficiently the size and density of exploited and unexploited Nautilus populations worldwide.

View Article: PubMed Central - PubMed

Affiliation: School of Biomedical Science, University of Queensland, Brisbane, Queensland, Australia. andy.dunstan@gmail.com

ABSTRACT
The low fecundity, late maturity, long gestation and long life span of Nautilus suggest that this species is vulnerable to over-exploitation. Demand from the ornamental shell trade has contributed to their rapid decline in localized populations. More data from wild populations are needed to design management plans which ensure Nautilus persistence. We used a variety of techniques including capture-mark-recapture, baited remote underwater video systems, ultrasonic telemetry and remotely operated vehicles to estimate population size, growth rates, distribution and demographic characteristics of an unexploited Nautilus pompilius population at Osprey Reef (Coral Sea, Australia). We estimated a small and dispersed population of between 844 and 4467 individuals (14.6-77.4 km(-2)) dominated by males (83:17 male:female) and comprised of few juveniles (<10%).These results provide the first Nautilid population and density estimates which are essential elements for long-term management of populations via sustainable catch models. Results from baited remote underwater video systems provide confidence for their more widespread use to assess efficiently the size and density of exploited and unexploited Nautilus populations worldwide.

Show MeSH
Related in: MedlinePlus