Effect of near-bottom currents on detection of bait by the abyssal grenadier fishes Coryphaenoides spp., recorded in situ with a video camera on a free vehicle

We used a novel mid-water baited remote underwater video (BRUV) technique to survey pelagic and mid-water fish assemblages at Lord Howe Island Marine Park, off eastern Australia (31.5°S, 159.1°E). We found differences in assemblages among regions separated on a scale of ~10s of kilometres. Of the environmental variables measured in the present study (depth, temperature, water current speed), current speed had the greatest influence on the structure of pelagic assemblages. Carcharhinus galapagensis, Seriola rivoliana and Scomber australasicus had similar distributions and were associated with low flow environments. Seriola lalandi was associated with the higher flow environments sampled during our surveys, although current speeds in the sample area were relatively slow (0.03 to 0.34 m s ). Relationships between pelagic assemblages and current speed were detected when abundances were calculated using an area-based approximation for plume dispersal, but were not detected using a linear approximation, or when current was assumed constant across all BRUV deployments. Our results demonstrate the difficulty in separating the dual effects of current speed in BRUV studies: the effect of current on bait plume size and associated estimates of fish abundance, and the role of current as an aspect of preferred pelagic fish habitat. We recommend the use of area-based approximations of plume dispersal and the inclusion of accurate estimates of current speed as a statistical covariate when interpreting mid-water BRUV data. Our results indicate that oceanographic characteristics can be important for pelagic fish habitat selection over the scale of kilometres and should be considered during marine protected area zoning.

Section: Estimating Fish Abundancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Pelagic fish assemblages assessed using mid-water baited video: standardising fish counts using bait plume size

Heagney¹,

Lynch²,

Babcock³

et al. 2007

“…As a result, arguments have been made for the value of in situ video and still imagery capture via vehicle-free or 'lander' systems (Phleger & Soutar 1971, Priede & Merrett 1996, Priede et al 1998. Baited cameras are highly effective at attracting scavengers and subsequent predators, which may be drawn in by the resulting chemosensory and perhaps mechanosensory stimuli (Wilson & Smith 1984, Smith 1985, Priede & Smith 1986, Henriques et al 2002. Many of the vehicle-free camera systems used to obtain images of the deep are also equipped with bright white illuminators; however, these illuminators are typically used as intermittent strobes and likely result in only a periodic effect (Wilson & Smith 1984, Priede et al 1998.…”

Section: Introductionmentioning

confidence: 99%

Behavioral responses of two deep-sea fish species to red, far-red, and white light

Raymond¹,

Widder²

2007

The relatively unobtrusive deep-sea camera system Eye-in-the-Sea (EITS) was deployed in Monterey Bay Canyon, California, USA, to assess the relative photosensitivity of 2 deepsea fishes, Coryphaenoides acrolepis and Anoplopoma fimbria. Previous studies addressing the in situ response of deep-sea fishes to red and white light were done in the presence of ROV-induced stimuli. Here, we report on the behavioral response of C. acrolepis and A. fimbria in a vehicle-free environment when subjected to white (full visible spectrum), red (685 nm), and far-red (695 nm) illumination in situ. Under far-red light conditions, A. fimbria spent significantly more time in the fieldof-view and demonstrated an increase in entrances/exits when compared to the situation under red-light and white-light conditions. No significant difference in the average time C. acrolepis spent in the field-of-view was found between any of the test wavelengths; however, the entrances-to-exits ratio for C. acrolepis decreased during white-light conditions. While A. fimbria often displayed a flight response at the onset of white and sometimes red (685 nm) illumination, C. acrolepis did not demonstrate a similar behavioral response when exposed to light within its range of visual sensitivity. A. fimbria undergo a dramatic ontogenic shift in depth, inhabiting well-lit, near-shore waters as juveniles and moving into deeper waters as adults. It is thought that C. acrolepis spend part of their early life history in the light-limited mesopelagic, below the permanent thermocline, and move into deeper waters as they mature. Based on the results of the present study, we hypothesize that systematic differences in the phototactic responses of deep-sea fishes are a function of life history as well as spectral sensitivity. KEY WORDS: Deep sea · Red light · Fish behaviorResale or republication not permitted without written consent of the publisher OPEN PEN ACCESS CCESS

“…Deep-sea macrourid fish, Coryphaenoides (Nematonurus) armatus and C. (N.) yaquinae, are attracted to baits deployed at abyssal depths (Wilson & Smith 1984). Movements of these fish can then be tracked since they will swallow (Priede & Smith 1986) and retain (Armstrong & Baldwin 1990) acoustic transmitters.…”

mentioning

confidence: 99%

“…The delay between FVV landing and arrival of the first fish seen swimming against the current ranged from 9 to 54 min with a mean of 31.0 min (n = 10, SD = 11.28). On 2 occasions fish that apparently did not detect the food were seen swimming across and down-current; these were excluded from the analysis since they were apparently not responding to the odour plume from the bait (Wilson & Smith 1984).…”

mentioning

confidence: 99%

Temporal change in foraging behaviour of the fish Coryphaenoides (Nematonurus) yaquinae in the central North Pacific

Armstrong¹,

Priede²,

Smith³

1991

Deep-sea grenadier fish Coryphaenoides (Nematonurus) yaquinae were attracted to a baited free-fall video camera and tracklng vehicle dunng 10 deployments in the central North Pacific (31°N, 159" W) at a depth of 5800 m. The mean time of arrival of the first fish was 31.0 min after landing on the sea floor. The mean number of fish within camera view increased to a peak of 5.25 at 90 min after landing and decreased thereafter The mitial arrival rate was 0.06 fish mm-', and mean fish staying time was 122 min The staying time was much shorter than in previous work at this site, suggesting a change in food supply with time of year Grenadiers were tracked using ingestible acoustic transmitters. The mean time until transmitter ingestion after the bait landed was 85.1 min. Fish that swallowed transmitters dispersed at radial rates of l to 20 cm S -' , and all had departed to a range of > 1000 m by 13 h after landlng. Movements to an altitude of > 15 m were recorded for 60 % of fish tracked and occupied 12.9 "10 of total tracking time. Bottom current speeds were between < 1 and 9 cm S-' with a tidal rhythmicity