Shark and ray community structure in a turbid, nearshore coral reef habitat

2020 ◽  
Vol 71 (9) ◽  
pp. 1194 ◽  
Author(s):  
Arthur Yon ◽  
Mark G. Meekan ◽  
Samantha Andrzejaczek ◽  
Sarah Martinez ◽  
Conrad W. Speed
Keyword(s):  
Austral Summer ◽  
Common Species ◽  
Northern Australia ◽  
Underwater Video ◽  
Reef Habitat ◽  
Management Zones ◽  
Marine Park ◽  
Abundance And Diversity ◽  
Carcharhinus Melanopterus ◽  
Coral Reef Habitat

The coastline of northern Australia may be a refuge for elasmobranchs threatened or extirpated from much of their former ranges across South-East Asia. In this study, we used baited remote underwater video stations to survey the abundance, size and assemblage of elasmobranchs in the Cobourg Marine Park in northern Australia. Two sites were sampled inside the park and one site was sampled outside the park, covering two management zones: open and partially protected. During the austral summer, 85 individuals of 12 species of elasmobranch were observed over 12 days. No significant differences were observed among sites in either size or abundance for common species. Videos were dominated by Carcharhinus melanopterus (relative abundance±s.d., 0.29±0.90h–1), Nebrius ferrugineus (0.03±0.24h–1) and Urogymnus granulatus (0.08±0.28h–1), which comprised >81% of all individuals. Environmental variables had no measurable effect on the abundance of elasmobranchs. The abundance and diversity of elasmobranchs in Cobourg Marine Park is high compared with other similar turbid, inshore areas of northern Australia. The large number of juveniles observed in our surveys also suggests the possibility of a nursery area.

Distribution, size and sex composition, reproductive biology and diet of sharks from Northern Australia

1991 ◽  
Vol 42 (2) ◽  
pp. 151 ◽  
Author(s):  
JD Stevens ◽  
KJ McLoughlin
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Annual Cycle ◽  
Post Partum ◽  
Austral Summer ◽  
Size Composition ◽  
Maximum Size ◽  
Northern Australia ◽  
Average Size ◽  
Size At Birth

The distribution, size composition, sex ratio, reproductive biology and diet of 17 species of shark from the families Triakidae, Hemigaleidae and Carcharhinidae from northern Australia were examined. In most of these species the sex ratio of the embryos is 1 : 1, whereas in the post-partum populations there were significantly more males than females. The results indicate four broad reproductive strategies among these sharks. In most species reproduction was distinctly seasonal with individual females giving birth each Austral summer (annual cycle) after a gestation period of 9-12 months. A second group had a very similar cycle except that individual females gave birth every second year (biennial cycle). A third group had an annual cycle but breeding was continuous throughout the year, these were mostly small bottom-associated sharks. One species had a seasonal cycle but gave birth twice each year (biannual cycle) after a 6-month gestation. The average size at birth varied from 27 to 75 cm and the average litter size varied from 2 to 34. The size at birth was about 40% of the size at maturity, which in turn was about 70% of the maximum size. Diets ranged from omnivorous to highly selective. Fish was an important component of the diet in all but one species. There was evidence of partitioning of food resources among sympatric, morphologically similar, sharks.

The importance of the terrestrial weathering feedback for multimillennial coral reef habitat recovery

2012 ◽  
Vol 26 (3) ◽  
Author(s):  
Katrin J. Meissner ◽  
Ben I. McNeil ◽  
Michael Eby ◽  
Edward C. Wiebe
Keyword(s):  
Coral Reef ◽  
Reef Habitat ◽  
Habitat Recovery ◽  
Coral Reef Habitat

The Climatology and Meteorology of High Fire Danger in the Northern Territory.

1993 ◽  
Vol 15 (2) ◽  
pp. 339 ◽  
Author(s):  
NJ Tapper ◽  
G Garden ◽  
J Gill ◽  
J Fernon
Keyword(s):  
Weather Forecasting ◽  
Austral Summer ◽  
Northern Territory ◽  
Dry Season ◽  
Fire Danger ◽  
Northern Australia ◽  
Weather Patterns ◽  
The North ◽  
Strong Winds ◽  
Objective Basis

In most areas of Australia the calculation of a fire danger index (FDI) is the cornerstone of fie weather forecasting and provides an operationally objective basis for the issue of fire weather warnings. FDI's are derived from the observation or prediction of a number of basic meteorological parameters which are then combined with information on fuel characteristics. The forest and grassland fire danger in southern Australia is greatest during the austral summer and is characterised by long periods of low fire danger interspersed with occasional extreme fire danger events. By contrast, much of tropical and subtropical Australia shows a distinctly different seasonality, magnitude and frequency of fire danger. The problem is essentially one of the austral winter-spring (dry season) period and is characterised by extended periods of moderate to high fire danger. This paper provides a broad climatological background to the problem of high fire danger in northern Australia, concentrating in particular on the Northern Territory. The paper also addresses particular meteorological situations in northern Australia which give rise to elevated fire danger. Two synoptic-scale weather patterns are discussed in particular; the passage of prefrontal troughs which seasonally produce high fire danger in the region of the tropic, and winter subtropical ridging which produces strong winds and high fire danger over the north of the continent during the dry season.

Coral reef habitat mapping: A combination of object-based image analysis and ecological modelling

2018 ◽  
Vol 208 ◽  
pp. 27-41 ◽  
Author(s):  
Chris Roelfsema ◽  
Eva Kovacs ◽  
Juan Carlos Ortiz ◽  
Nicholas H. Wolff ◽  
David Callaghan ◽  
...  
Keyword(s):  
Image Analysis ◽  
Coral Reef ◽  
Habitat Mapping ◽  
Ecological Modelling ◽  
Reef Habitat ◽  
Object Based Image Analysis ◽  
Object Based ◽  
Coral Reef Habitat

scholarly journals Somatic growth rates for a hawksbill turtle population in coral reef habitat around Barbados

2011 ◽  
Vol 432 ◽  
pp. 269-276 ◽  
Author(s):  
BH Krueger ◽  
MY Chaloupka ◽  
PA Leighton ◽  
JA Dunn ◽  
JA Horrocks
Keyword(s):  
Coral Reef ◽  
Growth Rates ◽  
Somatic Growth ◽  
Reef Habitat ◽  
Turtle Population ◽  
Coral Reef Habitat

scholarly journals MAPPING CORAL REEF HABITAT WITH AND WITHOUT WATER COLUMN CORRECTION USING QUICKBIRD IMAGE

2010 ◽  
Vol 2 (-) ◽  
Author(s):  
MARLINA NURLIDIASARI ◽  
SYARIF BUDIMAN
Keyword(s):  
Remote Sensing ◽  
Coral Reef ◽  
Water Column ◽  
Habitat Mapping ◽  
Likelihood Method ◽  
Remotely Sensed Data ◽  
Reef Habitat ◽  
Reef Environment ◽  
Very High Spatial Resolution ◽  
Coral Reef Habitat

Remote sensing from space offers an effective approach to solve the limitation of field sampling, in particular to monitor the reefs in remote sites. Moreover, using the achieved remotely sensed data, it is even possible to monitor the historic status of the coral reef environment. The capabilities of satellite remote sensing techniques combined with the field data collection have been assessed for generating coral reef habitat mapping of the Derawan Island. A very high spatial resolution multi-spectral QuickBird image (October 2003) has been used. The capability of QuickBird image to generate a coral reef habitat map with the water column correction by applying the Lyzenga method, and also without the water column correction by the applying maximum likelihood method, have been assessed. The classification accuracy of the coral reef habitat map increased after the improvement of the water column effects. The classification of QuickBird image for coral reef habitat mapping increased up to 22% by applying a water column correction. Keywords : Coral Reef, Quickbird, Water Column Correction

DENSITY AND THE COVERAGE OF SEAGRASS ECOSYSTEM IN BAHOI VILLAGE COASTAL WATERS, NOTRH SULAWESI

2017 ◽  
Vol 9 (1) ◽  
pp. 375-383 ◽  
Author(s):  
Muh. Fahruddin ◽  
Fredinan Yulianda ◽  
Isdradjad Setyobudiandi
Keyword(s):  
Coastal Waters ◽  
Seagrass Species ◽  
Reef Habitat ◽  
Thalassia Hemprichii ◽  
Halophila Ovalis ◽  
Seagrass Ecosystem ◽  
Seagrass Cover ◽  
Cymodocea Rotundata ◽  
Syringodium Isoetifolium ◽  
Coral Reef Habitat

Physical seagrass ecosystem damage have been reported in various regions in Indonesia. Seagrass ecosystem damage is caused by human activity such as trampling seagrass and boats that muddy the waters and reduced the density and seagrass cover. This study aims to provide information about the density and the coverage of seagrass. The method used in this research is the transect method measuring 50x50 cm squared at three different locations by considering coastal ecosystems Bahoi village that already exist. Station 1 is near to mangrove habitat, station 2 is right on seagrass habitats, and station 3 is near to coral reef habitat. The results indicated there is six seagrass species that found in the Bahoi village which is Enhalus acoroides, Thalassia hemprichii, Cymodocea rotundata, Syringodium isoetifolium, Halophila ovalis, and Halodule uninervis. The density and seagrass cover is shows that the station 1 has the highest density and seagrass cover percentage compared with the other stations. The highest density of seagrass species located in station 1 with 955 individuals/m2, and the lowest was located at station 3 with 699 individuals/m2. While the highest cover percentage is located at station 1 with 270% and the lowest located at station 3 with 229%. Keyword: seagrass ecosystem, density, coverage, Bahoi

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