Distribution and Abundance of Dugongs in the Northern Great Barrier-Reef Marine Park

1989 ◽  
Vol 16 (4) ◽  
pp. 429 ◽  
Author(s):  
H Marsh ◽  
WK Saalfeld
Keyword(s):  
Great Barrier Reef ◽  
Population Estimate ◽  
Seagrass Beds ◽  
Barrier Reef ◽  
Correction Factors ◽  
Water Turbidity ◽  
Density Estimates ◽  
Marine Park ◽  
Perception Bias ◽  
Specific Correction

In 1984 and 1985, dugongs were censused from the air at an overall sampling intensity of 9% over a total area of 31 288 km2 within the northern sections of the Great Barrier Reef Marine Park. Sightings were corrected for perception bias (the proportion of animals visible in the transect which are missed by observers), and availability bias (the proportion of animals that are invisible due to water turbidity) with survey-specific correction factors. There were no significant differences between population and density estimates obtained from repeat surveys of the same areas. The resultant population estimate (�s.e.) was 8110 � 1073 dugongs at an overall density (� s.e.) of 0.26�0.03 km-2, a precision of 13%. Dugongs occurred up to 58 km offshore and in water up to 37 m deep. The highest density of animals was seen on coastal seagrass beds at depths of <5 m. Maps of density and distribution are given. The design and timing of future surveys is also discussed.

Aerial Surveys of Sea Turtles in the Northern Great Barrier-Reef Marine Park

1989 ◽  
Vol 16 (3) ◽  
pp. 239 ◽  
Author(s):  
H Marsh ◽  
WK Saalfeld
Keyword(s):  
Great Barrier Reef ◽  
Sea Turtles ◽  
Analysis Of Covariance ◽  
Seagrass Beds ◽  
Barrier Reef ◽  
Sea State ◽  
Water Turbidity ◽  
Density Estimates ◽  
Marine Park ◽  
Specific Correction

In 1984 and 1985, during surveys designed primarily to census dugongs, six species of sea turtles were counted from the air at an overall sampling intensity of 9% over a total area of 31 288 km2 within the northern sections of the Great Barrier Reef Marine Park. The sea turtles were not identified to species. We attempted to correct sightings for perception bias (the proportion of animals visible in the transect which are missed by observers), and to standardise for availability bias (the.proportion of animals that are invisible due to water turbidity) with survey-specific correction factors. The resultant minimum population estimate in November 1985 was (mean � s.e.) 32 187 � 2532 sea turtles at an overall density of 1.03 � 0.08 km-2, a precision of 8%. We consider this to be a gross underestimate of numbers present. Significant differences between population and density estimates obtained from repeat surveys of the same areas were accounted for by differences in Beaufort sea state and cloud cover. The analysis of covariance data suggested that we had not been successful in standardising all biases. Turtles were widely distributed throughout the Great Barrier Reef lagoon from inshore seagrass beds to mid- and outer-shelf reefs. Highest densities were observed on inshore seagrass beds and on mid-shelf reefs, particularly between Murdoch Island and Cape Melville, and in Princess Charlotte Bay. Maps of density and distribution are given. We discuss the value and limitations of this survey regime for censusing sea turtles.

The distribution and abundance of the dugong in Shark Bay, Western Australia

1994 ◽  
Vol 21 (2) ◽  
pp. 149 ◽  
Author(s):  
H Marsh ◽  
RIT Prince ◽  
WK Saafeld ◽  
R Shepherd
Keyword(s):  
Western Australia ◽  
Large Scale ◽  
Correction Factors ◽  
Water Turbidity ◽  
Shark Bay ◽  
Northern Half ◽  
Perception Bias ◽  
Calving Rate ◽  
Specific Correction ◽  
Eastern Half

In July 1989, dugongs were counted from the air at an overall sampling intensity of 7.9% over 14 239 km2 in Shark Bay, Western Australia. Counts were corrected for perception bias (the proportion of dugongs visible in the transect that are missed by observers), and standardised for availability bias (the proportion of animals invisible because of water turbidity) with survey-specific correction factors. The resultant minimum population estimate was 10146 � 1665 (s.e.) dugongs at an overall density of 0.71 � 0.12 (s.e.) dugongs km-2, the highest density ever recorded on a large-scale dugong survey. The proportion of calves (19%) was higher than for most other dugong surveys conducted in Shark Bay and elsewhere, suggesting an exceptionally high calving rate in 1988. Dugong density was highest (>5 km-2) in relatively deep water (12-16 m) in the eastern half of Shark Bay opposite the tip of Peron Peninsula and in the western Bay opposite the northern half of Dirk Hartog Island. Fewer than 4% of dugongs sighted in Shark Bay during the survey were in waters colder than 18�C. Results of aerial surveys over 906 km2 in the Faure Sill region of the eastern Bay in November 1990 and January 1991 suggest that between a third and a half of the dugongs in Shark Bay are located in this region during the summer. In contrast, only one dugong was sighted there during the winter survey. The survey confirms that Shark Bay is an internationally significant dugong habitat.

Distribution and abundance of dugongs in Moreton Bay, Queensland, Australia

2003 ◽  
Vol 30 (4) ◽  
pp. 397 ◽  
Author(s):  
Janet M. Lanyon
Keyword(s):  
Hot Spots ◽  
Population Estimates ◽  
Correction Factors ◽  
Water Turbidity ◽  
Mean Intensity ◽  
Moreton Bay ◽  
Perception Bias ◽  
Species Specific ◽  
High Degree ◽  
Specific Correction

Dugong abundances in Moreton Bay (south-east Queensland) were estimated during six bi-monthly aerial surveys throughout 1995. Sampling intensity ranged between 20 and 80% for different sampling zones within the Bay, with a mean intensity of 40.5%. Population estimates for dugongs were corrected for perception bias (the proportion of animals visible in the transect that were missed by observers), and standardised for availability bias (the proportion of animals that were invisible due to water turbidity) with survey and species-specific correction factors. Population estimates for dugongs in Moreton Bay ranged from 503 ± 64 (s.e.) in July to 1019 ± 166 in January. The highest uncorrected count was 857 dugongs in December. This is greater than previous population estimates, suggesting that either previous surveys have underestimated abundance and/or that this population may have increased through recruitment, immigration, or a combination of both. The high degree of variation in population estimates between surveys may be due to temporal differences in distribution and herding behaviour. In winter, dugongs were found in smaller herds and were dispersed over a wider area than in summer. The Eastern Banks region of the bay supported 80–98% of the dugong population at any one time. Within this region, there were several dugong 'hot spots' that were visited repeatedly by large herds. These 'hot spots' contained seagrass communities that were dominated by species that dugongs prefer to eat. The waters of Rous Channel, South Passage and nearby oceanic waters are also frequently inhabited by dugongs in the winter months. Dugongs in other parts of Moreton Bay were at much lower densities than on the Eastern Banks.

Management of Water Quality in the Great Barrier Reef Marine Park

1989 ◽  
Vol 21 (2) ◽  
pp. 31-38 ◽  
Author(s):  
Simon Woodley
Keyword(s):  
Water Quality ◽  
Coral Reef ◽  
Great Barrier Reef ◽  
Barrier Reef ◽  
Management Issue ◽  
Reef System ◽  
Marine Park ◽  
World Heritage List ◽  
The World ◽  
Coral Reef System

The Great Barrier Reef is the largest coral reef system in the world. It is recognised and appreciated worldwide as a unique environment and for this reason has been inscribed on the World Heritage List. The Reef is economically-important to Queensland and Australia, supporting substantial tourism and fishing industries. Management of the Great Barrier Reef to ensure conservation of its natural qualities in perpetuity is achieved through the establishment of the Great Barrier Reef Marine Park. The maintenance of water quality to protect the reef and the industries which depend on it is becoming an increasingly important management issue requiring better knowledge and possibly new standards of treatment and discharge.

scholarly journals Lessons Learned from Australia’s Stakeholder Engagement Efforts for MPA Planning

2018 ◽  
Author(s):  
OCTO
Keyword(s):  
Great Barrier Reef ◽  
Stakeholder Engagement ◽  
Planning Process ◽  
Lessons Learned ◽  
Barrier Reef ◽  
Marine Park

Jon Day shares key lessons learned from stakeholder engagement efforts during the Representative Areas Program in the Great Barrier Reef, which was a key part of the comprehensive rezoning of the entire Marine Park between 1999 and 2003. As a result of this planning process, the total area of no-take zones increased from less than 5% to over one-third of the Marine Park, highlighting in large part the importance of effectively engaging stakeholders.

Great Barrier Reef

2008 ◽  
Author(s):  
Mike Kingsford ◽  
Ove Hoegh-Guldberg
Keyword(s):  
Climate Change ◽  
Coral Reef ◽  
Great Barrier Reef ◽  
Coral Disease ◽  
Barrier Reef ◽  
Physical Processes ◽  
Marine Park ◽  
The World ◽  
The Common ◽  
International Experts

The Great Barrier Reef Marine Park is 344 400 square kilometres in size and is home to one of the most diverse ecosystems in the world. This comprehensive guide describes the organisms and ecosystems of the Great Barrier Reef, as well as the biological, chemical and physical processes that influence them. Contemporary pressing issues such as climate change, coral bleaching, coral disease and the challenges of coral reef fisheries are also discussed. In addition,the book includes a field guide that will help people to identify the common animals and plants on the reef, then to delve into the book to learn more about the roles the biota play. Beautifully illustrated and with contributions from 33 international experts, The Great Barrier Reef is a must-read for the interested reef tourist, student, researcher and environmental manager. While it has an Australian focus, it can equally be used as a baseline text for most Indo-Pacific coral reefs. Winner of a Whitley Certificate of Commendation for 2009.

scholarly journals Long‐term dynamics and drivers of coral and macroalgal cover on inshore reefs of the Great Barrier Reef Marine Park

2019 ◽  
Vol 30 (1) ◽  
Author(s):  
Daniela M. Ceccarelli ◽  
Richard D. Evans ◽  
Murray Logan ◽  
Philippa Mantel ◽  
Marji Puotinen ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Barrier Reef ◽  
Macroalgal Cover ◽  
Marine Park

scholarly journals Quantifying Ship Strike Risk to Breeding Whales in a Multiple-Use Marine Park: The Great Barrier Reef

2020 ◽  
Vol 7 ◽  
Author(s):  
Joshua N. Smith ◽  
Natalie Kelly ◽  
Simon Childerhouse ◽  
Jessica V. Redfern ◽  
Thomas J. Moore ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Barrier Reef ◽  
Multiple Use ◽  
Marine Park ◽  
Ship Strike
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