scholarly journals Pacific Hagfish, Eptatretus stoutii, Spotted Ratfish, Hydrolagus colliei, and Scavenger Activity on Tethered Carrion in Subtidal Benthic Communities off Western Vancouver Island

2006 ◽  
Vol 120 (3) ◽  
pp. 363 ◽  
Author(s):  
Sarah Davies ◽  
Ali Griffiths ◽  
T. E. Reimchen
Keyword(s):  
Soft Tissues ◽  
Benthic Communities ◽  
Vancouver Island ◽  
Remotely Operated Vehicle ◽  
Video Cameras ◽  
Barkley Sound ◽  
Cancer Productus ◽  
Scavenger Activity ◽  
Eptatretus Stoutii ◽  
Food Falls

The influence of pelagic carrion food falls on marine benthic scavenging communities was investigated at two depths (10 m, 50 m) in Barkley Sound, west Vancouver Island, British Columbia from 12 May to 4 June, 2003. A remotely operated vehicle (ROV) equipped with video cameras was used to monitor anchored carrion (15 kg pig leg) during daylight and darkness. The videos were subsequently analyzed for species diversity, abundance and the intensity of scavenging. At 10 m, Redrock Crab (Cancer productus) and Kelp Greenling (Hexagrammos decagrammus) dominated, while at 50 m, Spot Shrimp (Pandalus platyceros), Spotted Ratfish (Hydrolagus colliei) and Pacific Hagfish (Eptatretus stoutii) were the dominant species, most of which were nocturnal. Hagfish were the major consumers of the carrion and after 23 days, no soft tissues remained at 50 m while 40% remained at 10 m. Within 24 hours of the carrion deployment, two of eleven ratfish succumbed, probably due to the direct clogging effects of hagfish mucus on the respiratory apparatus of the ratfish. These field observations are consistent with laboratory results suggesting high efficacy of hagfish mucus in competitive interactions.

Integrated geophysical modelling of terranes and other structural features along the western Canadian margin

1992 ◽  
Vol 29 (7) ◽  
pp. 1492-1508 ◽  
Author(s):  
S. A. Dehler ◽  
R. M. Clowes
Keyword(s):  
Seismic Refraction ◽  
Vancouver Island ◽  
Structural Features ◽  
Pacific Rim ◽  
Data Set ◽  
Reflection Seismic ◽  
Barkley Sound ◽  
The Pacific ◽  
Wrangellia Terrane ◽  
Lower Crustal

An integrated geophysical data set has been used to develop structural models across the continental margin west of Vancouver Island, Canada. A modern accretionary complex underlies the continental slope and shelf and rests against and below the allochthonous Crescent and Pacific Rim terranes. These terranes in turn abut against the pre-Tertiary Wrangellia terrane that constitutes most of the island. Gravity and magnetic anomaly data, constrained by seismic reflection, seismic refraction, and other data, were interpreted to determine the offshore positions of these terranes and related features. Iterative 2.5-dimensional forward models of anomaly profiles were stepped laterally along the margin to extend areal coverage over a 70 km wide swath oriented normal to the tectonic features. An average model was then developed to represent this part of the margin. The Pacific Rim terrane appears to be continuous and close to the coastline along the length of Vancouver Island, consistent with emplacement by strike-slip motion along the margin. The Westcoast fault, the boundary between the Pacific Rim and Wrangellia terranes, is interpreted to be 15 km farther seaward than in previous interpretations in the region of Barkley Sound. The Crescent terrane forms a thin landward-dipping slab along the southern half of the Vancouver Island margin, and cannot be confirmed along the northern part. Model results suggest the slab has buckled into an anticline beneath southern Vancouver Island and Juan de Fuca Strait, uplifting high-density lower crustal or upper mantle material close to the surface to produce the observed intense positive gravity anomaly. This geometry is consistent with emplacement of the Crescent terrane by oblique subduction.

scholarly journals Errata for 120(2): table of contents and 235-236; and 120(3): table of contents

2006 ◽  
Vol 120 (4) ◽  
pp. 503
Author(s):  
Francis Cook
Keyword(s):  
Benthic Communities ◽  
First Record ◽  
Common Reed ◽  
Lontra Canadensis ◽  
Current Status ◽  
Northern Coast ◽  
River Otter ◽  
Scavenger Activity ◽  
Invasion Pathway ◽  
Field Naturalist

Errata: The Canadian Field-Naturalist 120(2)Table of contents outside back cover:Conservation evaluation of Dwarf Wolly-heads, Psilocarphus brevissimus var. brevissimus, in CanadaGEORGE W. DOUGLAS, JENIFER L. PENNY, and KSENIA BARTON“Wolly-heads” should read Woolly-heads.Article page 235:First record of a River Otter, Lontra canadensis, captured on the northern coast of AlaskaSHAWN P. HASKELLIn abstract and citation “Lutra“ should be Lontra.Errata: The Canadian Field-Naturalist 120(3)Table of contents outside back cover:Recent invasion, current status, and invasion pathway of European Common Reed, Phragnites australis subspecies australis, in the southern Ottawa DistrictPAUL M. CATLING and SUSAN CARBYN“Phragnites“ should read Phragmites.Pacific Hagfish, Eppptatretus stoutii, Spotted Ratfish, Hydrolagus colliei, and scavenger activity on tethered carrion in subtidal benthic communities off western Vancouver IslandSARAH DAVIES, ALI GRIFFITHS, and T. E. REIMCHEN“Eppptatretus“ should read Eptatretus.

scholarly journals Remotely Operated Vehicle “ROV KIEL 6000“

2017 ◽  
Vol 3 ◽  
Author(s):  
Friedrich Abegg ◽  
Peter Linke
Keyword(s):  
Glass Fibers ◽  
Single Mode ◽  
Sampling Strategies ◽  
Remotely Operated Vehicle ◽  
Video Cameras ◽  
Deep Diving ◽  
In Situ Data ◽  
Umbilical Cable ◽  
Surface Vessel

The remotely operated vehicle ROV KIEL 6000 is a deep diving platform rated for water depths of 6000 meters. It is linked to a surface vessel via an umbilical cable transmitting power (copper wires) and data (3 single-mode glass fibers). As standard it comes equipped with still and video cameras and two different manipulators providing eyes and hands in the deep. Besides this a set of other tools may be added depending on the mission tasks, ranging from simple manipulative tools such as chisels and shovels to electrically connected instruments which can send in-situ data to the ship through the ROVs network, allowing immediate decisions upon manipulation or sampling strategies.

scholarly journals The First Cut Is the Deepest: Trawl Effects on a Deep-Sea Sponge Ground Are Pronounced Four Years on

2020 ◽  
Vol 7 ◽  
Author(s):  
Katelin M. Morrison ◽  
Heidi Kristina Meyer ◽  
Emyr Martyn Roberts ◽  
Hans Tore Rapp ◽  
Ana Colaço ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Deep Sea ◽  
Multivariate Analyses ◽  
Benthic Communities ◽  
Bottom Trawl ◽  
Physical Disturbance ◽  
Remotely Operated Vehicle ◽  
The Status ◽  
And Control ◽  
Distinct Separation

Few studies have described the effects of physical disturbance and post-recovery of deep-sea benthic communities. Here, we explore the status of deep-sea sponge ground communities four years after being impacted by an experimental bottom trawl. The diversity and abundance of epibenthic megafauna of two distinct benthic communities in disturbed versus control areas were surveyed using a remotely operated vehicle on the Schulz Bank, Arctic Ocean. Four years after disturbance, megafaunal densities of the shallow (∼600 m depth) and deep (∼1,400 m depth) sites were significantly lower on the disturbed patches compared to the control areas. Multivariate analyses revealed a distinct separation between disturbed and control communities for both sites, with trawling causing 29–58% of the variation. Many epibenthic morphotypes were significantly impacted by the trawl, including ascidians, Geodia parva, Hexactinellida spp., Craniella infrequens, Lissodendoryx complicata, Haliclonia sp. Stylocordyla borealis, Gersemia rubiformis and Actiniaria sp. However, we found some smaller morphospecies to be equally abundant with control transects, including Polymastia thielei, Geodia hentscheli, and Stelletta rhaphidiophora, reflecting lower trawl impact for these morphotypes. Overall, our results suggest that these are fragile ecosystems that require much more time than four years to recover from physical disturbance typical of trawling activities.

Surficial Sediments of Barkley Sound and the Adjacent Continental Shelf, West Coast Vancouver Island

1973 ◽  
Vol 10 (4) ◽  
pp. 441-459 ◽  
Author(s):  
Lionel Carter
Keyword(s):  
Continental Shelf ◽  
West Coast ◽  
Circulatory System ◽  
Vancouver Island ◽  
Sediment Distribution ◽  
Barkley Sound ◽  
Holocene Transgression ◽  
Hydraulic Regime ◽  
River Valleys ◽  
Inner Continental Shelf

The bathymetry and sediment distribution of Barkley Sound and the adjacent continental shelf off the west coast of Vancouver Island have been markedly affected by the late Pleistocene glaciation and modern sedimentary processes. Several fjords widen and coalesce to form the sound, which is continuous with glacially eroded basins on the inner continental shelf. These basins are flanked by flat-topped banks, the larger of which merge with the outer shelf—a gently sloping plain that terminates at the 200 m isobath, 58 km from shore.Modern sediments are restricted mainly to Barkley Sound where the glaciated "basin and sill" bathymetry and an estuarine circulatory system prevent the predominantly muddy detritus from reaching the continental shelf. Relict sands and gravels cover most of the shelf except within basins and drowned river valleys where muds prevail. This relict cover was initially dispersed by glaciers and meltwater streams, then later inundated during the Holocene Transgression, and is now being partly reworked by the present hydraulic regime. Near the shelf-break relict sediments are sparse and authigenic sands (glaucontized mudstone pellets) predominate together with residual sediments derived from submarine exposures of Tertiary mudstone.

Seasonal Shifts in the Spawning Site of a Northeast Pacific Intertidal Fish

1975 ◽  
Vol 32 (10) ◽  
pp. 1687-1691 ◽  
Author(s):  
Jeffrey B. Marliave
Keyword(s):  
Vancouver Island ◽  
Wave Action ◽  
Northeast Pacific ◽  
Barkley Sound ◽  
Spawning Site ◽  
Seasonal Shift ◽  
Intertidal Fish ◽  
Xiphister Atropurpureus ◽  
Seasonal Shifts

In Barkley Sound, Vancouver Island, Canada, the spawning of the black prickleback, Xiphister atropurpureus, occurs during winter on rocky beaches protected from wave action. However, during spring, spawning occurs on rocky beaches of increasing exposure. This species spawns only under boulders with pebble, small rock, or shell substrates. Coincident reduction of wave action and increases in temperature probably cause the seasonal shift in the spawning site of this stichaeid.

Convergence of Acoustic, Optical, and Net-Catch Estimates of Euphausiid Abundance: Use of Artificial Light to Reduce Net

1993 ◽  
Vol 50 (2) ◽  
pp. 334-346 ◽  
Author(s):  
D. Sameoto ◽  
N. Cochrane ◽  
A. Herman
Keyword(s):  
Target Strength ◽  
Sampling System ◽  
Remotely Operated Vehicle ◽  
Acoustic Backscattering ◽  
Video Cameras ◽  
Acoustic Target ◽  
Avoidance Reactions ◽  
Theoretical Scattering ◽  
System Operating

Euphausiid concentrations in the Scotian Shelf basins were sampled with BIONESS, a multinet sampling system, and quantitatively assessed simultaneously with an in situ optical zooplankton counter (OPC) mounted on BIONESS and with an acoustic backscattering system operating simultaneously at 50, 122, and 200 kHz. Supplementary observations were made with vertically dropped video cameras and video and 35-mm frame cameras mounted on a remotely operated vehicle (ROV). The use of a light source on BIONESS during sampling increased the catch of euphausiids by 10–20 times by reducing active avoidance reactions to the net. Consequently, conventional net sampling has greatly underestimated euphausiid concentrations, a conclusion suggested by previous acoustic measurements. Experimental acoustic target strengths for 28-mm euphausiids averaged −77.5, −73.4, and −68.4 dB at 50, 122, and 200 kHz, respectively, using measured Sv levels and assuming 100% net sampling efficiency. Theoretical scattering models based on randomly oriented cylinders require the euphausiids to be oriented within about 5° of the horizontal to approximate both the experimentally observed target strength amplitudes and their frequency dependence. Acoustic interpretation has been enhanced by incorporation of transducer sensitivity versus temperature corrections and modeling techniques that allow for finite transducer beam widths.

scholarly journals Bathyal feasting: post-spawning squid as a source of carbon for deep-sea benthic communities

2017 ◽  
Vol 284 (1869) ◽  
pp. 20172096 ◽  
Author(s):  
H. J. T. Hoving ◽  
S. L. Bush ◽  
S. H. D. Haddock ◽  
B. H. Robison
Keyword(s):  
Water Column ◽  
Deep Sea ◽  
Gulf Of California ◽  
Benthic Communities ◽  
Food Sources ◽  
Medium Size ◽  
Natural Food ◽  
Carbon Budgets ◽  
Remotely Operated Vehicle ◽  
Geographical Regions

In many oceanic carbon budgets there is a discrepancy between the energetic requirements of deep-sea benthic communities and the supply of organic matter. This suggests that there are unidentified and unmeasured food sources reaching the seafloor. During 11 deep-sea remotely operated vehicle (ROV) surveys in the Gulf of California, the remains (squid carcasses and hatched-out egg sheets) of 64 post-brooding squid were encountered. As many as 36 remains were encountered during a single dive. To our knowledge this is one of the largest numbers of natural food falls of medium-size deep-sea nekton described to date. Various deep-sea scavengers (Ophiuroidea, Holothuroidea, Decapoda, Asteroidea, Enteropneusta) were associated with the remains. Although many of the 80 examined ROV dives did not encounter dead squids or egg sheets ( n = 69), and the phenomenon may be geographically and temporally restricted, our results show that dead, sinking squid transport carbon from the water column to the seafloor in the Gulf of California. Based on food fall observations from individual dives, we estimate that annual squid carcass depositions may regionally contribute from 0.05 to 12.07 mg C m −2 d −1 to the seafloor in the areas where we observed the remains. The sinking of squid carcasses may constitute a significant but underestimated carbon vector between the water column and the seafloor worldwide, because squid populations are enormous and are regionally expanding as a result of climate change and pressure on fish stocks. In the future, standardized methods and surveys in geographical regions that have large squid populations will be important for investigating the overall contribution of squid falls to regional carbon budgets.

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