Dugong distribution, the seagrass Halophila spinulosa, and thermal environment in winter indeeper waters of eastern Shark Bay, WA

1994 ◽  
Vol 21 (4) ◽  
pp. 381 ◽  
Author(s):  
PK Anderson
Keyword(s):  
Deep Water ◽  
Thermal Environment ◽  
Benthic Communities ◽  
Aerial Survey ◽  
Underwater Video ◽  
Shark Bay ◽  
Forage Species ◽  
Monospecific Stand ◽  
Thermal Patterns ◽  
Time And Energy

Five aerial survey transects in eastern Shark Bay, along which dugongs (Dugong dugon) had been reported in deep water in July 1989, were flown on 3 and 14 July 1992. As in 1989, dugong sightings were concentrated between 9- and 15-m depth contours. Thermal patterns shown on images obtained from NOAA satellites, and direct measurement of temperatures in the water column, confirmed that temperatures were at least 19�C where dugongs were concentrated. Although no seagrass had previously been reported in this zone, examination of benthic communities using a remotely controlled underwater video system revealed an apparently monospecific stand of Halophila spinulosa. Dugong behaviour, observed from a 10-m catamaran, indicated that the animals were diving to the bottom. Long, deep dives may be more costly in time and energy than the shorter dives characteristic of feeding in shallow water. H. spinulosa has large fleshy rhizomes similar to those known to contain abundant starch in other members of the genus and it is suggested that carbohydrate-rich rhizomes might compensate for the higher costs of foraging in deep water. Previously known stands of preferred forage species appeared inadequate to support the large dugong population of Shark Bay, but if temperatures are favourable throughout the winter and if the H. spinulosu observed in this study is available throughout the year, this H. spinulosa community may be an important resource for the Shark Bay dugong population.

scholarly journals A novel design for sampling benthic zooplankton communities in disparate Gulf of Alaska habitats using an autonomous deep-water plankton pump

2020 ◽  
Vol 42 (4) ◽  
pp. 457-466
Author(s):  
Rachel E Wilborn ◽  
Christopher N Rooper ◽  
Pam Goddard ◽  
Kresimir Williams ◽  
Rick Towler
Keyword(s):  
Deep Water ◽  
Cold Water ◽  
Larval Fish ◽  
Low Cost ◽  
Benthic Communities ◽  
Gulf Of Alaska ◽  
Design Parameters ◽  
Benthic Habitat ◽  
Pump Design ◽  
Zooplankton Communities

Abstract Deep-water larval fish and zooplankton utilize structurally complex, cold-water coral and sponge (CWCS) habitats as refuges, nurseries and feeding grounds. Fine-scale sampling of these habitats for larval fish and zooplankton has proven difficult. This study implemented a newly designed, autonomous, noninvasive plankton pump sampler that collected large mesozooplankton within 1 m of the seafloor. It was successfully deployed in the western Gulf of Alaska between the Shumagin Islands (~158°W) and Samalga Pass (−170°W), and collected in situ zooplankton from diverse benthic communities (coral, sponge and bare substrates) at depths in excess of 100 m. Key design parameters of the plankton pump were its ability to be deployed from ships of opportunity, be untethered from the vessel during sampling and be deployed and retrieved in high-relief, rocky areas where CWCS are typically present. The plankton pump remains stationary while collecting from the water column, rests within 1 m of the seafloor and captures images of the surrounding habitat and substrate. This plankton pump design is a low-cost, highly portable solution for assessing the role of benthic habitat in the life cycle of mesozooplankton, a linkage that has been relatively underexplored due to the difficulty in obtaining near-bottom samples.

Studies of Dugons at Shark Bay, Western Australia I. Analysis of Population Size, Composition, Dispersion and Nabitat USe on the Basis of Aerial Survey

1982 ◽  
Vol 9 (1) ◽  
pp. 69 ◽  
Author(s):  
PK Anderson
Keyword(s):  
Population Size ◽  
Western Australia ◽  
Cloud Cover ◽  
Size Composition ◽  
Aerial Survey ◽  
Vegetation Patterns ◽  
Depressing Effect ◽  
Shark Bay ◽  
Or Groups ◽  
Analysis Of Dispersion

In midwinter dugongs concentrate in western Shark Bay, adjacent to Dirk Hartog I., although scattered individuals or groups remain in other regions. Up to 496 dugongs were counted in intensively surveyed western areas in July 1979. At least 553 individuals are calculated to have been present in the region, and a minimum population of over 900 individuals estimated for the Bay as a whole. The population seems to be a well defined isolate, and is relatively undisturbed. Conditions are very favourable for more detailed study. A method for estimating the number of animals overlooked in the blind zone directly beneath the aircraft is described. Aerial counts of dugongs varied greatly with conditions. Cloud cover had a large depressing effect: surface turbulence and subsurface turbidity were less significant. Dugong activity is concentrated on the sublittoral platform. Sites of major aggregation may not be the same in successive years. Locally favoured habitats are at the seaward margins of the sublittoral platform, and on offshore shoals. Vegetation patterns at favoured sites may reflect dugong grazing. Persistent use of favoured localities, and local shifts in concentration were observed. Distribution of other large vertebrates, and of boats, relative to that of dugongs was examined and a significant correlation between sightings of large sharks and larger aggregations of dugongs was found. Analysis of dispersion revealed that most dugongs were in groups although most sightings were of single individuals. Cows with calves were less likely to be in the company of other dugongs than were adults without calves. From ll to 12% of individuals were calves.

scholarly journals Species identification in seamount fish aggregations using moored underwater video

2012 ◽  
Vol 69 (4) ◽  
pp. 648-659 ◽  
Author(s):  
Richard L. O'Driscoll ◽  
Peter de Joux ◽  
Richard Nelson ◽  
Gavin J. Macaulay ◽  
Adam J. Dunford ◽  
...  
Keyword(s):  
Species Identification ◽  
Deep Water ◽  
Underwater Video ◽  
Orange Roughy ◽  
Video Cameras ◽  
Order Of Magnitude ◽  
Acoustic Surveys ◽  
To Come ◽  
Along Track ◽  
Fish Response

Abstract O'Driscoll, R. L., de Joux, P., Nelson, R., Macaulay, G. J., Dunford, A. J., Marriott, P. M., Stewart, C., and Miller, B. S. 2012. Species identification in seamount fish aggregations using moored underwater video. – ICES Journal of Marine Science, 69: 648–659. Acoustic surveys of New Zealand deep-water seamounts often show fish aggregations up to 150 m high on the summit. Although bottom trawls on the seamount slopes catch predominantly orange roughy (Hoplostethus atlanticus), species composition in the midwater plumes is extremely uncertain. In June 2010, moored underwater video cameras were deployed on the summit of the Morgue seamount (summit depth 890 m), a feature that has been closed to fishing since 2001. Cameras and lights were timed to come on for 2 min every 2 h. Fish response to the mooring was monitored using vessel-mounted echosounders. Moored cameras confirmed that orange roughy were present up to 70 m above the seamount summit. Orange roughy made up 97% of the fish identified from the video. Other species observed included smooth oreo (Pseudocyttus maculatus), spiky oreo (Neocyttus rhomboidalis), deep-water dogfish, cardinalfish (Epigonus spp.), and squid. Total along-track backscatter from the plume varied by a factor of 25 over a period of hours. Peak acoustic densities in the plume (equivalent to 20 orange roughy m−3) were an order of magnitude higher than peak visual estimates (0.64 orange roughy m−3), but relative densities between paired video and acoustic observations were generally consistent.

scholarly journals Unveiling the Perth Canyon and its deep-water faunas

2018 ◽  
Author(s):  
Julie A. Trotter ◽  
Charitha Pattiaratchi ◽  
Paolo Montagna ◽  
Marco Taviani ◽  
James Falter ◽  
...  
Keyword(s):  
Deep Water ◽  
Benthic Communities ◽  
Ice Age ◽  
Intermediate Water ◽  
Depth Range ◽  
High Definition ◽  
Nuclear Bomb ◽  
Early Oligocene ◽  
Deep Waters ◽  
Water Depths

Abstract. The Perth Canyon is a prominent submarine valley system in the southeast Indian Ocean that incises the southwest Australian continental shelf. It is characterised by two main steep-sided valleys forming a V-shaped configuration that extend from a depth of ~ 600 m to the abyssal plain at ~ 4000 m. Despite its prominence and location of only ~ 27 nautical miles (50 km) offshore, this study represents the first ROV-based exploration of the canyon and its inhabitants. ROV surveys revealed quiescent environments, the structure essentially representing a fossil canyon system with localised occurrences of significant mega- and macrobenthos in the depth range of ~ 680 to ~ 1800 m. The patchy distribution of canyon life comprised corals, sponges, molluscs, echinoderms, crustaceans, brachiopods, and worms, as well as plankton and nekton (various fish species) especially near benthic communities. High definition video surveys and biomass sampling were complemented by ship-based multi-beam bathymetry, and seawater CTD profiling and chemical analyses. ROV transects were conducted at six geomorphologically distinct locations, from the head to the mouth of the canyon and on the northern shelf plateau. The dives traversed the generally featureless muddy canyon floor, along near vertical walls, and onto the canyon rim. ROV imaging revealed typically massive and well-bedded sedimentary units that are variably lithified and mostly friable. Biostratigraphic and palaeoecological analysis of foraminifers from rock and sediment samples (~ 700 to 1600 m) indicate that they were deposited from the Late Paleocene to Early Oligocene within upper-middle bathyal (~ 200 to ~ 700 m) water depths, thus implying that significant subsidence has occurred. Strontium isotope (87Sr/86Sr) dating also suggests the presence of Early Miocene sediments at the shallower sites. Settlement of large benthic sessile organisms is largely limited to indurated substrates mostly along the canyon walls. Corals were specifically targeted, with solitary (Desmophyllum dianthus, Caryophyllia sp., Vaughanella sp., and Polymyces sp.) and colonial (Solenosmilia variabilis) scleractinians found sporadically distributed along the walls and beneath overhangs in the deeper canyon valleys as well as along the canyon rims. Gorgonian, bamboo, and proteinaceous corals were also present with noticeable patches of live Corallium hosting a diverse community of organisms. Extensive coral graveyards were discovered between ~ 690–720 m and 1560–1790 m comprising colonial (S. variabilis) and solitary (D. dianthus) scleractinians, which had flourished during the last ice age between ~ 18 ka to 33 ka (BP). Faunal sampling (674 m to 1815 m) spans the intermediate and deep waters, which were identified as Antarctic Intermediate Water and Upper Circumpolar Deep Water, with temperatures of ~ 2.5 to ~ 6 °C. The carbonate chemistry of those water depths show supersaturation (Ωcalc ~ 1.3 to 2.2) with respect to calcite, but mild saturation to undersaturation (Ωarag ~ 0.8 to 1.4) with respect to aragonite. Notably, some scleractinians inhabit depths below the aragonite saturation horizon (~ 1000 m). Depth profile measurements of δ13C and nuclear bomb produced Δ14C show decreases within the upper canyon waters of up to ~ 0.8 ‰ (

scholarly journals The influence of environmental setting on the community ecology of Ediacaran organisms

2019 ◽  
Author(s):  
Emily G. Mitchell ◽  
Nikolai Bobkov ◽  
Natalia Bykova ◽  
Alavya Dhungana ◽  
Anton Kolesnikov ◽  
...  
Keyword(s):  
Community Ecology ◽  
Shallow Water ◽  
Deep Water ◽  
Benthic Communities ◽  
Bedding Plane ◽  
Depositional Environments ◽  
Time Interval ◽  
Benthic Environment ◽  
A Chain ◽  
Broad Scale

AbstractThe broad-scale environment plays a substantial role in shaping modern marine ecosystems, but the degree to which palaeocommunities were influenced by their environment is unclear. To investigate how broad-scale environment influenced the community ecology of early animal ecosystems we employed spatial point process analyses to examine the community structure of seven bedding-plane assemblages of late Ediacaran age (558–550 Ma), drawn from a range of environmental settings and global localities. The studied palaeocommunities exhibit marked differences in the response of their component taxa to sub-metre-scale habitat heterogeneities on the seafloor. Shallow-marine palaeocommunities were heavily influenced by local habitat heterogeneities, in contrast to their deep-water counterparts. Lower species richness in deep-water Ediacaran assemblages compared to shallow-water counterparts across the studied time-interval could have been driven by this environmental patchiness, because habitat heterogeneities correspond to higher diversity in modern marine environments. The presence of grazers and detritivores within shallow-water communities may have promoted local patchiness, potentially initiating a chain of increasing heterogeneity of benthic communities from shallow to deep-marine depositional environments. Our results provide quantitative support for the “Savannah” hypothesis for early animal diversification – whereby Ediacaran diversification was driven by patchiness in the local benthic environment.Author ContributionsE. Mitchell conceived this paper and wrote the first draft. N. Bobkov, A. Kolesnikov, N. Sozonov and D. Grazhdankin collected the data for DS surface. N. Bobkov and N. Sozonov performed the analyses on DS surface. N. Bykova, S. Xiao, and D. Grazhdankin collected the data for WS, KH1 and KH2 surfaces and E. Mitchell performed the analyses. A. Dhungana and A. Liu collected the data for FUN4 and FUN5 surfaces and A. Dhungana performed the analyses. T. Mustill and D. Grazhdankin collected the data for KS and T. Mustill and E. Mitchell performed the analyses. I. Hogarth developed the software for preliminary KS surface analyses. E. Mitchell, N. Bobkov, N. Bykova, A. Dhungana, A. Kolesnikov, A. Liu, S. Xiao and D. Grazhdankin discussed the results and prepared the manuscript.

Mapping of the benthic communities in the Taranto seas using side-scan sonar and an underwater video camera

2004 ◽  
Vol 20 (5) ◽  
pp. 377-386 ◽  
Author(s):  
A. Matarrese ◽  
F. Mastrototaro ◽  
G. D'onghia ◽  
P. Maiorano ◽  
A. Tursi
Keyword(s):  
Benthic Communities ◽  
Video Camera ◽  
Underwater Video ◽  
Side Scan Sonar ◽  
Underwater Video Camera

scholarly journals New records of the rare deep-water alga Sebdenia monnardiana (Rhodophyta) and the alien Dictyota cyanoloma (Phaeophyceae) and the unresolved case of deep-water kelp in the Ionian and Aegean Seas (Greece)

2019 ◽  
Vol 62 (6) ◽  
pp. 577-586 ◽  
Author(s):  
Frithjof C. Küpper ◽  
Konstantinos Tsiamis ◽  
Niko Rainer Johansson ◽  
Akira F. Peters ◽  
Maria Salomidi ◽  
...  
Keyword(s):  
Shallow Water ◽  
Deep Water ◽  
New Records ◽  
Eastern Mediterranean ◽  
Benthic Communities ◽  
Scuba Diving ◽  
First Record ◽  
Special Focus ◽  
East Mediterranean ◽  
Remotely Operated Vehicle

Abstract Parts of the macroalgal flora of the eastern Mediterranean remain incompletely known. This applies in particular to the circalittoral communities. This study, based upon 2 cruises in the Ionian and Aegean Seas, surveyed benthic communities from 40 to 150 m depth by remotely-operated vehicle (ROV) with a special focus on detecting communities of the Mediterranean deep-water kelp Laminaria rodriguezii. These were complemented by shallow-water surveys on adjacent coastlines by snorkelling and scuba diving. While no kelp could be detected at any of the sites surveyed, ROV surveys of northern Euboia Island revealed the first east Mediterranean record of Sebdenia monnardiana (Sebdeniales, Rhodophyta). Snorkelling surveys on the coast of southeast Kefalonia yielded the first record of the alien alga Dictyota cyanoloma in Greece. This paper reports rbcL and SSU sequences for Sebdenia monnardiana, and COI for Dictyota cyanoloma.

Summer survey of dugong distribution and abundance in Shark Bay reveals additional key habitat area

2006 ◽  
Vol 33 (3) ◽  
pp. 243 ◽  
Author(s):  
David K. Holley ◽  
Ivan R. Lawler ◽  
Nicholas J. Gales
Keyword(s):  
Large Scale ◽  
Aerial Survey ◽  
Seasonal Migration ◽  
Population Estimate ◽  
Entire Region ◽  
Shark Bay ◽  
The North ◽  
Exmouth Gulf ◽  
First Time ◽  
Summer Survey

The first standardised summer aerial survey of dugongs within Shark Bay in Western Australia, and the fourth in a series of surveys of this area, was undertaken during February 2002. This survey returned a population estimate of 11 021 ± 1357 (s.e.), a result similar to the first two winter surveys in 1989 and 1994 but considerably lower than the 1999 survey. Distribution was markedly different in this survey compared with all previous surveys, which were conducted during winter, confirming that dugongs within Shark Bay undertake a seasonal migration driven by changes in sea surface temperature. In addition to this distribution pattern it was identified that 24% of the population during summer occurred within an area known as Henri Freycinet Harbour. That is, while dugongs have been reported in this south-western region of the bay previously in summer, this is the first time that the substantial size (2629 ± 780, s.e.) of the summer dugong population has been quantified. Differences in the population estimate between the 1999 survey and this survey may be explained through large-scale movement patterns of dugongs between Shark Bay and Ningaloo Reef and Exmouth Gulf to the north, patterns that should be considered in the management of dugongs for the entire region.

scholarly journals Abundance estimates of Southern Hemisphere Breeding Stock ‘D’ humpback whales from aerial and land-based surveys off Shark Bay, Western Australia, 2008

2020 ◽  
pp. 209-221
Author(s):  
Sharon L. Hedley ◽  
John L. Bannister ◽  
Rebecca A. Dunlop
Keyword(s):  
Southern Hemisphere ◽  
Western Australia ◽  
Aerial Survey ◽  
Humpback Whales ◽  
Line Transect ◽  
Breeding Stock ◽  
Abundance Estimate ◽  
Shark Bay ◽  
Abundance Estimates ◽  
Rate Of Increase

Single platform aerial line transect and land-based surveys of Southern Hemisphere Breeding Stock ‘D’ humpback whales Megaptera novaeangliaewere undertaken off Shark Bay, Western Australia to provide absolute abundance estimates of animals migrating northward along the westernAustralian coast. The aerial survey flew a total of 28 flights, of which 26 were completed successfully, from 24 June–19 August 2008. The landbased survey was undertaken from Cape Inscription, Dirk Hartog Island, Shark Bay, during the expected peak of the whales’ northward migration,from 8–20 July. During the first week of the land-based survey, some double count effort was undertaken to provide information on the numbersof pods missed from the land station. The assumed period of northward migration was 2 June–7 September. Estimated abundance of northwardmigrating whales during that time is 34,290 (95% CI: (27,340–53,350)), representing an annual rate of increase of 12.9% (CV = 0.20) since anestimate of 11,500 in 1999. This estimate is based on an estimate of relative abundance of surface-available whales of 10,840 (8,640–16,860), andan estimated g(0) of 0.32. There were considerable practical difficulties encountered during the land-based survey which reduced the effectivenessof the dual-survey approach for estimating g(0) for the aerial survey. Furthermore only about 15% of whales were estimated to be within the visualrange of the land-based station. Alternative approaches for estimating g(0) from these data are therefore also presented, resulting in considerablyhigher estimates of around 0.6–0.7, and yielding a conservative abundance estimate of 17,810 (14,210–27,720).

Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

1988 ◽  
Vol 62 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Near Surface ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Platform Margin ◽  
Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

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