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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

Osprey Reef: Nautilus sampling and tracking detection sites.Nautilus trapping was done at eight sites (red stars, t = number of samples at each site around Osprey Reef totalling 303 samples of which 92% were at the Entrance site, n = total number of Nautilus captured and r = % recaptures of total capture number). Baited Remote Underwater Video System deployments (black circles) were undertaken at two sites while Remotely Operated Vehicle dives (yellow triangles) were done at four sites with two dives at both Pavona and Coral castles. A VR2 receiver at Mid-East Wall recorded the presence of one Nautilus released at Entrance.
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pone-0016716-g002: Osprey Reef: Nautilus sampling and tracking detection sites.Nautilus trapping was done at eight sites (red stars, t = number of samples at each site around Osprey Reef totalling 303 samples of which 92% were at the Entrance site, n = total number of Nautilus captured and r = % recaptures of total capture number). Baited Remote Underwater Video System deployments (black circles) were undertaken at two sites while Remotely Operated Vehicle dives (yellow triangles) were done at four sites with two dives at both Pavona and Coral castles. A VR2 receiver at Mid-East Wall recorded the presence of one Nautilus released at Entrance.

Mentions: We deployed and successfully retrieved 268 traps at the Entrance site, Osprey Reef, from August, 2000 to January, 2006, resulting in the capture of 1553 individual Nautilus (1203 males, 251 females and 99 immature/juveniles) and the recapture of 157 individuals (Fig. 2). Nautilus pompilius was the only species captured. There was some indication of a seasonal trend for sampling maxima towards the middle months of the year; however, catches within the 95% confidence interval of mean catch rates (6.4 trap−1) were returned throughout all months, with February being the only month without sampling effort (Fig. S1).


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

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

Osprey Reef: Nautilus sampling and tracking detection sites.Nautilus trapping was done at eight sites (red stars, t = number of samples at each site around Osprey Reef totalling 303 samples of which 92% were at the Entrance site, n = total number of Nautilus captured and r = % recaptures of total capture number). Baited Remote Underwater Video System deployments (black circles) were undertaken at two sites while Remotely Operated Vehicle dives (yellow triangles) were done at four sites with two dives at both Pavona and Coral castles. A VR2 receiver at Mid-East Wall recorded the presence of one Nautilus released at Entrance.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0016716-g002: Osprey Reef: Nautilus sampling and tracking detection sites.Nautilus trapping was done at eight sites (red stars, t = number of samples at each site around Osprey Reef totalling 303 samples of which 92% were at the Entrance site, n = total number of Nautilus captured and r = % recaptures of total capture number). Baited Remote Underwater Video System deployments (black circles) were undertaken at two sites while Remotely Operated Vehicle dives (yellow triangles) were done at four sites with two dives at both Pavona and Coral castles. A VR2 receiver at Mid-East Wall recorded the presence of one Nautilus released at Entrance.
Mentions: We deployed and successfully retrieved 268 traps at the Entrance site, Osprey Reef, from August, 2000 to January, 2006, resulting in the capture of 1553 individual Nautilus (1203 males, 251 females and 99 immature/juveniles) and the recapture of 157 individuals (Fig. 2). Nautilus pompilius was the only species captured. There was some indication of a seasonal trend for sampling maxima towards the middle months of the year; however, catches within the 95% confidence interval of mean catch rates (6.4 trap−1) were returned throughout all months, with February being the only month without sampling effort (Fig. S1).

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