Regulate or tolerate: Thermal strategy of a coral reef flat resident, the epaulette shark, Hemiscyllium ocellatum

2020 ◽  
Author(s):  
Tiffany J Nay ◽  
Rohan J Longbottom ◽  
Connor R Gervais ◽  
Jacob L Johansen ◽  
John F Steffensen ◽  
...  
Keyword(s):  
Coral Reef ◽  
Reef Flat ◽  
Epaulette Shark

Rheotaxis by epaulette sharks, Hemiscyllium ocellatum (Chondrichthyes : Hemiscylliidae), on a coral reef flat

2002 ◽  
Vol 50 (4) ◽  
pp. 407 ◽  
Author(s):  
M. B. Peach
Keyword(s):  
Coral Reef ◽  
Reef Flat ◽  
Current Direction ◽  
Barrier Reef ◽  
Water Currents ◽  
Preferred Direction ◽  
Epaulette Shark ◽  
Quantitative Studies ◽  
Apparent Relationship ◽  
In The Wild

Rheotaxis (orientation to water currents) is commonly observed in fishes. Facing upstream is thought to be an element of shark behaviour during prey search and station-holding, but quantitative studies of rheotaxis by sharks in the wild are lacking. In this study, rheotaxis by the epaulette shark, Hemiscyllium ocellatum, was investigated on a coral reef flat at Heron Island, Great Barrier Reef, Australia. The orientation of 78 individuals in open areas (on sand or on top of coral heads, directly exposed to the prevailing current) was analysed with respect to current direction and velocity. H. ocellatum showed a significant (P < 0.05) preference for facing upstream (mean angle 1�, where the current origin was taken to be 0/360�) while resting on the substrate (n = 23), but showed no evidence of a preferred direction while swimming (n = 50). Observations of foraging were few (n = 5) but there was no indication of a preferred direction by these sharks. Resting H. ocellatum faced significantly more upstream at faster current velocities (P < 0.05), suggesting that rheotaxis may function in station-holding. There was no apparent relationship between rheotaxis and current velocity for swimming H. ocellatum.

scholarly journals Impacts of ocean acidification in naturally variable coral reef flat ecosystems

2012 ◽  
Vol 117 (C3) ◽  
pp. n/a-n/a ◽  
Author(s):  
Emily C. Shaw ◽  
Ben I. McNeil ◽  
Bronte Tilbrook
Keyword(s):  
Coral Reef ◽  
Ocean Acidification ◽  
Reef Flat

scholarly journals Pair formation, home range, and spatial variation in density, size and social status in blotched foxfaceSiganus unimaculatuson an Okinawan coral reef

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1280 ◽  
Author(s):  
Atsushi Nanami
Keyword(s):  
Coral Reef ◽  
Home Range ◽  
Spatial Variation ◽  
Reef Flat ◽  
Pair Formation ◽  
Size Class ◽  
Reef Slope ◽  
Rocky Reef ◽  
Seagrass Bed ◽  
Agonistic Display

The present study examined pair formation, spatial pattern of home range and spatial variation in density, size and social status of blotched foxfaceSiganus unimaculatus(family Siganidae) on an Okinawan coral reef. Of 32 pairs sampled for sexing, 31 (96.9%) were heterosexual and showed size-assortative pairing. Developed ovaries were found in April and July, whereas oocytes were immature in August, September and February. Heterosexual pairing was found in both reproductive and non-reproductive periods. Home range size tended to be positively related to fork length (FL). The degree of home range overlap for same size class pairs was smaller than that for different size class pairs. The intraspecific behavior when two pairs approached each other was categorized as ‘attack,’ ‘agonistic display’ and ‘no interactions,’ and the frequency of agonistic behaviors (“attack” or “agonistic display”) was significantly greater than “no interactions.” Underwater observations at a seagrass bed, a rocky reef flat and a sheltered reef slope revealed that the mean FL was significantly smaller at the sheltered reef slope (4–13 cm) than at the rocky reef flat (>13 cm). No individuals were found in the seagrass bed. Most individuals less than 6 cm FL were solitary, whereas most individuals over 7 cm FL were paired. Density was significantly greater on the sheltered reef slope than on the rocky reef flat.

scholarly journals Carbonate System Parameters of an Algal-dominated Reef along West Maui

2018 ◽  
Author(s):  
Nancy G. Prouty ◽  
Kimberly K. Yates ◽  
Nathan Smiley ◽  
Chris Gallagher ◽  
Olivia Cheriton ◽  
...  
Keyword(s):  
Coral Reef ◽  
Reef Flat ◽  
Sampling Period ◽  
Total Alkalinity ◽  
Carbonate Chemistry ◽  
Diurnal Variability ◽  
Carbon Chemistry ◽  
Sources Of Pollution ◽  
Seawater Ph ◽  
Chemistry Dynamics

Abstract. Constraining coral reef metabolism and carbon chemistry dynamics are fundamental for understanding and predicting reef vulnerability to rising coastal CO2 concentrations and decreasing seawater pH. However, few studies exist along reefs occupying densely inhabited shorelines with known input from land-based sources of pollution. The shallow coral reefs off Kahekili, West Maui, are exposed to nutrient-enriched, low-pH submarine groundwater discharge (SGD) and are particularly vulnerable to the compounding stressors from land-based sources of pollution and lower seawater pH. To constrain the carbonate chemistry system, nutrients and carbonate chemistry were measured along the Kahekili reef flat every 4 h over a 6-d sampling period in March 2016. Abiotic process – primarily SGD fluxes – controlled the carbonate chemistry adjacent to the primary SGD vent site, with nutrient-laden freshwater decreasing pH levels and favoring undersaturated aragonite saturation (Ωarag) conditions. In contrast, diurnal variability in the carbonate chemistry at other sites along the reef flat was driven by reef community metabolism. Superimposed on the diurnal signal was a transition during the second sampling period to a surplus of total alkalinity (TA) and dissolved inorganic carbon (DIC) compared to ocean end-member TA and DIC measurements. A shift from net community production and calcification to net respiration and carbonate dissolution was identified. This transition occurred during a period of increased SGD-driven nutrient loading, lower wave height, and reduced current speeds. This detailed study of carbon chemistry dynamics highlights the need to incorporate local effects of nearshore oceanographic processes into predictions of coral reef vulnerability and resilience.

Mass-transfer-limited nitrate uptake on a coral reef flat, Warraber Island, Torres Strait, Australia

Coral Reefs ◽  
2004 ◽  
Vol 23 (3) ◽  
pp. 386-396 ◽  
Author(s):  
Mark E. Baird ◽  
Moninya Roughan ◽  
Robert W. Brander ◽  
Jason H. Middleton ◽  
Greg J. Nippard
Keyword(s):  
Mass Transfer ◽  
Coral Reef ◽  
Nitrate Uptake ◽  
Reef Flat ◽  
Torres Strait

SPATIAL AND TEMPORAL VARIABILITY IN RIPPLE FORMATION AND MIGRATION ACROSS A CORAL REEF FLAT AND LAGOON

2019 ◽  
Author(s):  
KURT ROSENBERGER ◽  
CURT STORLAZZI ◽  
ANDREW POMEROY ◽  
OLIVIA CHERITON ◽  
RYAN LOWE ◽  
...  
Keyword(s):  
Coral Reef ◽  
Temporal Variability ◽  
Reef Flat ◽  
Spatial And Temporal Variability ◽  
Ripple Formation ◽  
And Migration

scholarly journals POPULATION STRUCTURE OF Acanthaster planci ON THE REEF FLAT AT THE SOUTHERN PART OF BUNAKEN ISLAND

2013 ◽  
Vol 1 (1) ◽  
pp. 34
Author(s):  
Patritia Napitupulu ◽  
Hanny Tioho ◽  
Agung Windarto
Keyword(s):  
Population Structure ◽  
Coral Reef ◽  
Reef Flat ◽  
Adult Population ◽  
Acanthaster Planci ◽  
Night Time ◽  
Coverage Area ◽  
Reef Management ◽  
Coral Reef Management ◽  
Coral Reef Ecosystems

The information on population structure of Acanthaster planci in Bunaken National Park (BNP) is urgent to be presented in order to be considered in decision making especially on coral reef management in BNP. The objectives of  this study was to examine the  population structure of A. planci, represented by the diameter and weight, number of arms, while the density, distribution and types of coral predation by reef animals in the Southern part of Bunaken Island also observed. Data were collected at the three locations namely, front reef flat (FRF), middle reef flat (MRF) and back reef flat (BRF) with total coverage area of ​​100 x 50 meters. Sixty two individuals (41 at night and 21 at day time) were found with a body diameter ranging between 14 – 28 cm, whereas body weight ranged from 80 – 700 gr, with the number of arms between 9 until 17. The density of A. planci during day time was 0.0042 ind/m2, while the night time was 0.0082 ind/m2, moreover the animal is generally spread aggregated. The results of this study indicated that the population of A. planci in BNP was an adult population with density is still relatively normal, despite an alert sign for the sustainability of coral reef ecosystems in the BNP.

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