Diving and Foraging Behaviors

Keith-Diagne, Lucy W.; Barlas, Margaret E.; Reid, James P.; Hodgson, Amanda; Marsh, Helene

doi:10.1007/978-3-030-90742-6_3

Cited by 6 publications

(5 citation statements)

References 97 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The modelling also revealed that metazoan species such as polychaetes and small molluscs could participate in the isotopic values of dugong tissues, a result confirmed by our stomach content analysis. Deliberate consumption of invertebrates by dugongs has been reported in some studies 31 as a response to a seasonal rarefaction of resources in winter at high latitudes 37 and could participate to meet the nitrogen nutritive requirement of dugongs 15 . Here, metazoans species overlapped more with the trophic niche of adult females and contributed more to their estimated mix.…”

Section: Discussionmentioning

confidence: 97%

“…While satellite tracking matched with spatially concurrent seagrass in-situ surveys have provided valuable insights into the foraging behaviour of dugongs 18 , 22 , 34 , 35 , knowledge of their diet remains limited to few visual observations (e.g., feeding herds 33 ; grazing tracks 20 , 34 ) and analyses of mouth, stomach or faecal contents of stranded individuals 11 , 36 , 37 . However, these investigations are either geographically limited to a few study sites (grazing tracks) or to few (likely unhealthy) individuals whose diet is assessed over a very short time window (gut content from stranded individuals).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

C and N stable isotopes enlighten the trophic behaviour of the dugong (Dugong dugon)

Thibault,

Letourneur,

Cleguer

et al. 2024

Sci Rep

View full text Add to dashboard Cite

The dugong (Dugong dugon), a large marine mammal herbivore of the Indo-Pacific, is vulnerable to extinction at a global scale due to a combination of human-related threats including habitat degradation. The species forages on seagrass habitats (marine phanerogams) and plays a key role in the functioning and sensitivity of these declining coastal ecosystems. The trophic behaviour and plasticity of dugong populations in response to extrinsic and intrinsic factors are therefore crucial features to both dugong and seagrass conservation. Yet, this knowledge remains limited to few visual observations and analyses of mouth, stomach or faecal contents of stranded individuals. We take advantage of a long-term monitoring of stranded individuals from the endangered New Caledonian population to depict features of dugongs’ trophic ecology from Carbon and Nitrogen stable isotopes. A total of 59 dugong skin samples were used to portrait the stable isotope niche of dugongs according to their sex and maturity. In light of previous work conducted in New Caledonia, a subset of these samples was used to model the trophic mix of dugong males and females. Our stable isotope mixing models used C and N isotope values of 10 taxa bbelonging to five divisions of metazoans, plants, and chromists. Our results represent the first estimate of the species dietary niche in the isotopic space. They suggest that the diet of dugong calves overlaps more with that of adult females (δ13C: − 6.38 ± 1.13 ‰; δ15N: 2.49 ± 1.10 ‰) than males (δ13C: − 5.92 ± 1.10 ‰; δ15N: 3.69 ± 1.28 ‰). Further, we highlight differences in the expected trophic mix of dugong adult males and females. From these, we formulate a sex-specific foraging behaviour hypothesis in dugongs, whereby lactating females could forage over smaller spatial ranges but more diverse food sources thanmales. The study emphasizes the importance of long-term stranding monitoring programs to study the ecology of marine mammals.. Finally, it depicts an ecological feature that may contribute to the sensitivity of vulnerable dugongs to ongoing changes on tropical coastal ecosystems.

show abstract

Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

C and N stable isotopes enlighten the trophic behaviour of the dugong (Dugong dugon)

Thibault,

Letourneur,

Cleguer

et al. 2024

Sci Rep

View full text Add to dashboard Cite

show abstract

“…The estimated geographical coordinates were then obtained with a Global Positioning System and the dugongs were observed more closely with binoculars. Since evaluating dugong abundance through boat‐based surveys is challenging due to the elusive nature of dugongs and limited water visibility in their habitats (Hodgson, 2011; Aragones et al, 2012a; Keith‐Diagne et al, 2022), three independent observers estimated the size of dugong groups encountered during boat surveys. First, the observers estimated the maximum number of dugongs seen on the surface using binoculars.…”

Section: Methodsmentioning

confidence: 99%

“…Owing to the paucity of historical records of dugongs, the persistence of the dugong population around Bahrain was assessed, the February 15, 2021, survey, the percentage of individuals located within two dugong body lengths of nearest neighbours was also calculated. To identify habitats in key areas occupied by LDGs, six groups were observed until they moved away from their feeding spots (as indicated by their repetitive diving and the sediment plume generated by feeding; Hodgson, 2004;Marshall et al, 2018;Keith-Diagne et al, 2022) and then the benthos was visually examined by snorkelling or scuba.…”

Section: Compilation Of Past and Present Data On Ldgsmentioning

confidence: 99%

Long‐term persistence of large dugong groups in a conservation hotspot around Hawar Island, Kingdom of Bahrain

Khamis

Abdulla

D’Souza

et al. 2023

Aquatic Conservation

View full text Add to dashboard Cite

Predictable aggregations of large marine mammals are valuable conservation targets, but aggregated populations can also be exposed to site‐level threats. The globally vulnerable Dugong dugon has a wide distribution but is found in large numbers mainly in Australia and the Arabian Gulf. Though Australian dugong populations are well studied, much less is known of the dugongs in the Arabian Gulf. The spatial and temporal persistence of dugongs around Bahrain, with a focus on large dugong groups (>50 dugongs), was determined using an occupancy modelling framework supported by historical records, structured interviews, citizen science network reports, and small‐scale boat and unmanned aerial vehicle surveys. Historical records and current distributional studies confirmed that large dugong groups have been reliably sighted around Hawar Island (Bahrain) since at least 1986, forming large, clumped groups that persist almost year round. The largest recorded so far in the world, these fluid groups (maximum of ~700 dugongs) account for ~60% of the dugongs found in Bahrain and ~12% of all dugongs in the Arabian Gulf. The delineated occupancy core area of large dugong groups (~145 km2) straddles the Bahrain–Qatar border, reflecting the transboundary nature of these groups. Careful management of human‐induced stressors (in particular, fishing, boating, and coastal development) combined with regular monitoring of Hawar Island's large dugong groups and their seagrass habitat is critical to safeguard this globally important population. The effectiveness of any conservation management is predicated on strengthening cooperation among all range states in the Arabian Gulf. A key recommendation of this study is to establish a regional network of marine protected areas encompassing core aggregation sites for dugongs, particularly the Hawar Islands in Bahrain, the north‐western waters of Qatar, Marawah Island in the United Arab Emirates in addition to the shallow waters between Saudi Arabia, Qatar, and United Arab Emirates.

show abstract

“…

maintain the osmotic balance (Ortiz et al, 1998). Therefore, they tend to seek out inland freshwater resources or coastal freshwater springs (Favero et al, 2020;Keith-Diagne et al, 2022), a behavior that significantly influences their distribution and movements. The availability of resources will ultimately shape the utilization of these environments according to the energy requirements of each individual (Deutsch et al, 2022).Because of their habitat preferences, manatees often use areas near human settlements, and consequently face several anthropogenic impacts such as hunting (Calvimontes &

…”

mentioning

confidence: 99%

Manatees across borders: Introduction to the special issue on the biology and conservation of manatees

Meirelles,

Castelblanco-Martinez,

Borges

et al. 2024

Lat. Am. J. Aquat. Mamm.

View full text Add to dashboard Cite

maintain the osmotic balance (Ortiz et al., 1998). Therefore, they tend to seek out inland freshwater resources or coastal freshwater springs (Favero et al., 2020;Keith-Diagne et al., 2022), a behavior that significantly influences their distribution and movements. The availability of resources will ultimately shape the utilization of these environments according to the energy requirements of each individual (Deutsch et al., 2022).Because of their habitat preferences, manatees often use areas near human settlements, and consequently face several anthropogenic impacts such as hunting (Calvimontes &

show abstract

Diving and Foraging Behaviors

Cited by 6 publications

References 97 publications

C and N stable isotopes enlighten the trophic behaviour of the dugong (Dugong dugon)

C and N stable isotopes enlighten the trophic behaviour of the dugong (Dugong dugon)

Long‐term persistence of large dugong groups in a conservation hotspot around Hawar Island, Kingdom of Bahrain

Manatees across borders: Introduction to the special issue on the biology and conservation of manatees

Contact Info

Product

Resources

About