A Method for Capturing Dugongs (&lt;I&gt;Dugong dugon&lt;/I&gt;) in Open Water

Lanyon, Janet M.; Slade, Rob; Sneath, Helen L.; Broderick, Damien; Kirkwood, John M.; Limpus, Duncan J.; Limpus, Colin J.; Jessop, Tim S.

doi:10.1578/am.32.2.2006.196

Cited by 43 publications

(35 citation statements)

References 5 publications

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“…A mark-recapture program to examine the ecology and population dynamics of dugongs in Moreton Bay, southeast Queensland, has been conducted since 2000 (Lanyon et al, 2002(Lanyon et al, , 2006. In this program, individual dugongs have been captured and tagged, and faecal samples, uncontaminated by seawater, have been obtained by insertion of a soft latex tube into the distal rectum of each animal (Lanyon et al, 2002(Lanyon et al, , 2006.…”

Section: Samples From Wild Dugongsmentioning

confidence: 99%

See 1 more Smart Citation

Bacterial Community Structure in the Hindgut of Wild and Captive Dugongs (Dugong dugon)

Eigeland¹,

Lanyon²,

Trott³

et al. 2012

Aquat Mamm

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Dugongs (Dugong dugon) are marine mammals that obtain nutrients through hindgut fermentation of seagrass, however, the microbes responsible have not been identified. This study used denaturing gradient gel electrophoresis (DGGE) and 454-pyrosequencing to profile hindgut bacterial communities in wild dugongs. Faecal samples obtained from 32 wild dugongs representing four size/maturity classes, and two captive dugongs fed on cos lettuce were screened using DGGE. Partial 16S rRNA gene profiles of hindgut bacteria from wild dugong calves and juveniles were grouped together and were different to those in subadults and adults. Marked differences between hindgut bacterial communities of wild and captive du gongs were also observed, except for a single captive whose profile resembled wild adults following an unsuccessful reintroduction to the wild. Pyrosequencing of hindgut communities in two wild dugongs confirmed the stability of bacterial populations, and Firmicutes (average 75.6% of Operational Taxonomic Units [OTUs]) and Bacteroidetes (19.9% of OTUs) dominated. Dominant genera were Roseburia, Clostridium, and Bacteroides. Hindgut microbial composition and diversity in wild dugongs is affected by ontogeny and probably diet. In captive dugongs, the absence of the dominant bacterial DNA bands identified in wild dugongs is probably dependent upon prevailing diet and other captive conditions such as the use of antibiotics. This study represents a first step in the characterisation of a novel microbial ecosystem-the marine hindgut of Sirenia.

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Section: Samples From Wild Dugongsmentioning

confidence: 99%

“…In this program, individual dugongs have been captured and tagged, and faecal samples, uncontaminated by seawater, have been obtained by insertion of a soft latex tube into the distal rectum of each animal (Lanyon et al, 2002(Lanyon et al, , 2006. Faecal samples (2 to 10 g) were stored at -20° C until further analysis.…”

Section: Samples From Wild Dugongsmentioning

confidence: 99%

Bacterial Community Structure in the Hindgut of Wild and Captive Dugongs (Dugong dugon)

Eigeland¹,

Lanyon²,

Trott³

et al. 2012

Aquat Mamm

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“…When a dugong was encountered, it was recorded as being either solitary or a member of a group. Dugongs of both sexes and all ages (except neonates) were captured and restrained at the water surface for a short period (5-6 min; Lanyon et al 2006). Each dugong was tagged for identification (Lanyon et al 2002) and sexed (Lanyon et al 2006).…”

Section: Data Collectionmentioning

confidence: 99%

“…Dugongs of both sexes and all ages (except neonates) were captured and restrained at the water surface for a short period (5-6 min; Lanyon et al 2006). Each dugong was tagged for identification (Lanyon et al 2002) and sexed (Lanyon et al 2006). Body size of each dugong was based on total body length measured in a straight line from snout to fluke notch, and maximum girth measured at the umbilicus position.…”

Section: Data Collectionmentioning

confidence: 99%

Testosterone and tusks: maturation and seasonal reproductive patterns of live, free-ranging male dugongs (Dugong dugon) in a subtropical population

Burgess

Lanyon²,

Keeley³

2012

Reproduction

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Knowledge of male reproductive status and activity in free-ranging animals is vital to understanding reproductive patterns and population dynamics. Until now, almost all information regarding reproductive behavior of the dugong, a cryptic marine mammal, has relied on post-mortem examination. We examined the relationships between body length, tusk eruption (secondary sexual characteristic), seasonality, and group association on fecal testosterone metabolite concentrations in 322 free-ranging dugongs (159 males, 163 females) in subtropical Moreton Bay, Australia. Fecal testosterone concentrations demonstrated biologically meaningful differences in testicular activity between sexes and across reproductive/age classes, and were correlated with circulating concentrations in serum. Male dugongs have a pre-reproductive period that persists until a body length of 240 cm is achieved. Puberty apparently occurs between 240 and 260 cm body length when fecal testosterone levels increase fourfold (O500 ng/g) over juvenile levels, and is associated with tusk eruption. However, social maturity may be delayed until male dugongs are larger than 260 cm with well-developed tusks. In mature males, the lowest (!500 ng/g) fecal testosterone concentrations occur in the austral autumn months with maximal concentrations in September-October, coincident with the onset of a spring mating season. During spring, solitary mature males had fecal testosterone concentrations double those of mature males sampled within groups, potentially suggesting a mating strategy involving roving of reproductively active males. This study demonstrates that single-point physiological data from individuals across a population have value as indicators of reproductive processes. Our approach provides an efficacious non-lethal method for the census of reproductive status and seasonality in live male dugongs.

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“…1) in 2012, 2013 and 2014 using the rodeo method developed by Marsh & Rathbun (1990) and refined by Lanyon et al (2006). For each dugong, sex was noted, total body length was measured (cm) in a straight line from snout to fluke notch and a titanium ID tag was attached as standard protocol (Limpus 1992).…”

Section: Methodsmentioning

confidence: 99%

Quick Fix GPS technology highlights risk to dugongs moving between protected areas

Zeh¹,

Heupel²,

Hamann³

et al. 2016

Endang. Species. Res.

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Incidental capture in fishing gear is the most serious threat to the survival of many species of marine mammals. Fisheries closures developed to protect marine mammals have tended to concentrate on areas of high marine mammal density. Movement corridors have generally been less protected because they are often unknown and difficult to detect. Seagrass meadows in Moreton and Hervey Bays in south-eastern Queensland support significant populations of dugongs Dugong dugon. Pedigree analysis based on genetic and ancillary biological data indicates that there is substantial movement of dugongs between these bays, which are separated by open surf coasts where dugongs are occasionally caught in inshore shark nets set for the protection of bathers. This bycatch suggests that the dugong movement corridor between Moreton and Hervey Bays is close to the coast, a hypothesis not confirmed by nearly 30 yr of dugong satellite tracking using platform transmitter terminal (PTT) technology. Twenty-nine dugongs were captured in seagrass habitats on the eastern banks of Moreton Bay in 2012−2014 and were fitted with Quick Fix GPS and acoustic transmitters. One animal was captured and tracked twice. Four dugongs were tracked moving from Moreton Bay to Hervey Bay covering distances of 278− 338 km over 5−9 d; 1 dugong made the return journey. Three of the 4 animals travelled along and very close to the coast; the exact track of the fourth animal is uncertain. These results suggest that dugongs would benefit from netting closures that extend beyond seagrass meadows.

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A Method for Capturing Dugongs (<I>Dugong dugon</I>) in Open Water

Cited by 43 publications

References 5 publications

Bacterial Community Structure in the Hindgut of Wild and Captive Dugongs (Dugong dugon)

Bacterial Community Structure in the Hindgut of Wild and Captive Dugongs (Dugong dugon)

Testosterone and tusks: maturation and seasonal reproductive patterns of live, free-ranging male dugongs (Dugong dugon) in a subtropical population

Quick Fix GPS technology highlights risk to dugongs moving between protected areas

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