scholarly journals How much fish is hidden in the surface and bottom acoustic blind zones?

2009 ◽  
Vol 66 (6) ◽  
pp. 1355-1363 ◽  
Author(s):  
Carla Scalabrin ◽  
Christian Marfia ◽  
Jean Boucher
Keyword(s):  
Continental Shelf ◽  
Autonomous Underwater Vehicle ◽  
Distribution Patterns ◽  
Underwater Vehicle ◽  
Fish Distribution ◽  
Scattering Coefficient ◽  
Research Vessel ◽  
Bay Of Biscay ◽  
Acoustic Surveys ◽  
Scientific Payload

Abstract Scalabrin, C., Marfia, C., and Boucher, J. 2009. How much fish is hidden in the surface and bottom acoustic blind zones? – ICES Journal of Marine Science, 66: 1355–1363. This paper presents results from the ALLEGRO-07 survey that was carried out from 1 to 15 September 2007 across the continental shelf in the Bay of Biscay by the RV “Thalassa”. The main objectives were to conduct experiments with a medium-sized, autonomous underwater vehicle (AUV) equipped with a fishery-acoustic scientific payload. This was needed to overcome the difficulties of sampling the surface and bottom blind zones, which are inaccessible to conventional, vessel-mounted transducers used for acoustic surveys in the Bay of Biscay. The AUV acoustic datasets from four dives were compared with those from the research vessel. The results were expressed for the nautical-area-scattering coefficient (sA) and biomass estimates. The AUV provided higher sA measurements than did the vessel. For particular environmental and fish-distribution patterns, the biomass estimated by the AUV was more than ten times that estimated by the vessel alone. The results presented indicate the magnitude of the error that may occur in acoustic surveys, if the biomass in the two blind zones is undetected.

Jellyfish distribution and abundance in relation to the physical habitat of Jellyfish Lake, Palau

2018 ◽  
Vol 34 (1) ◽  
pp. 17-31 ◽  
Author(s):  
Megan A. Cimino ◽  
Sharon Patris ◽  
Gerda Ucharm ◽  
Lori J. Bell ◽  
Eric Terrill
Keyword(s):  
Autonomous Underwater Vehicle ◽  
Size Fraction ◽  
Underwater Vehicle ◽  
Habitat Associations ◽  
Physical Habitat ◽  
Uv Damage ◽  
Tourist Destination ◽  
Novel Approach ◽  
Abundance Estimates ◽  
Acoustic Surveys

Abstract:Animals often select for habitats that increase their chance of survival by balancing the need to acquire food, reproduce and avoid predation. Perennial blooms of golden jellyfish (Mastigias papua etpisoni) are present in Jellyfish Lake, Palau, a popular tourist destination. Based on the species’ economic importance and unusual behavioural complexity, increased understanding of jellyfish habitat selection is necessary. We used a novel approach, a REMUS autonomous underwater vehicle, to quantify jellyfish distribution, abundance and habitat, and compared these findings to traditional methods. Midday acoustic surveys showed jellyfish distribution was patchy and the population resided mainly on the eastern side of the lake, as it is known that jellyfish migrate eastward towards the sun. Highest vertical densities of jellyfish were at 6–7 m, potentially to mitigate UV damage or photoinhibition of their photosymbionts, suggesting a coupling exists between their vertical distribution and water properties. Abundance estimates of jellyfish were ~2.75 and ~7.1 million (~2 million excluding bell diameters <1 cm) from acoustic and net samples, suggesting the methodology employed underestimated the population's smaller size fraction and non-synoptic surveys could impact estimates due to unresolved patchiness. Our approach could investigate population dynamics, behaviour or habitat associations on fine scales.

scholarly journals Acoustic surveys for juvenile anchovy in the Bay of Biscay: abundance estimate as an indicator of the next year's recruitment and spatial distribution patterns

2013 ◽  
Vol 70 (7) ◽  
pp. 1354-1368 ◽  
Author(s):  
G. Boyra ◽  
U. Martínez ◽  
U. Cotano ◽  
M. Santos ◽  
X. Irigoien ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Distribution Patterns ◽  
Horizontal Distribution ◽  
Bay Of Biscay ◽  
Spatial Distribution Patterns ◽  
Abundance Estimate ◽  
Juvenile Abundance ◽  
Wide Range ◽  
Acoustic Surveys ◽  
Management Advice

Abstract Boyra, G., Martínez, U., Cotano, U., Santos, M., Irigoien, X., and Uriarte, A. 2013. Acoustic surveys for juvenile anchovy in the Bay of Biscay: abundance estimate as an indicator of the next year's recruitment and spatial distribution patterns. – ICES Journal of Marine Science, 70: . A series of acoustic surveys (JUVENA) began in 2003 targeting juvenile anchovy (Engraulis encrasicolus) in the Bay of Biscay. A specific methodology was designed for mapping and estimating juvenile abundance annually, four months after the spawning season. After eight years of the survey, a consistent picture of the spatial pattern of the juvenile anchovy has emerged. Juveniles show a vertical and horizontal distribution pattern that depends on size. The younger individuals are found isolated from other species in waters closer to the surface, mainly off the shelf within the mid-southern region of the bay. The largest juveniles are usually found deeper and closer to the shore in the company of adult anchovy and other pelagic species. In these eight years, the survey has covered a wide range of juvenile abundances, and the estimates show a significant positive relationship between the juvenile biomasses and the one-year-old recruits of the following year. This demonstrates that the JUVENA index provides an early indication of the strength of next year's recruitment to the fishery and can therefore be used to improve the management advice for the fishery of this short-lived species.

scholarly journals Exploration of Underwater Volcano Teisi by Autonomous Underwater Vehicle ""R-One Robot""

2002 ◽  
Vol 14 (2) ◽  
pp. 157-161 ◽  
Author(s):  
Kenji Nagahashi ◽  
◽  
Takashi Obara ◽  
Tamaki Ura ◽  
Keyword(s):  
Autonomous Underwater Vehicle ◽  
Underwater Vehicle ◽  
Research Vessel ◽  
Side Scan Sonar

This paper presents the exploration of underwater volcano (Teisi Knoll, Ito City, Shizuoka Pref.) by an Autonomous Underwater Vehicle (AUV) ""R-One Robot"" in October 2000. The ""R-One Robot"" was launched from the research vessel (R/V) Kaiyo in the scheduled submerging area, autonomously ascertained the direction for diving into the sea, navigated precisely passing through all way points, and lastly, surfaced right on the point as programmed. The robot succeeded in taking acoustics photographs of the crater by Side Scan Sonar on the bottom of the robot.

Development of a Semi-Autonomous Underwater Vehicle for Intervention Missions (SAUVIM Phase III-B)

2009 ◽  
Author(s):  
Giacomo Marani ◽  
Junku Yuh ◽  
Song K. Choi ◽  
Son-Cheol Yu ◽  
Luca Gambella ◽  
...  
Keyword(s):  
Autonomous Underwater Vehicle ◽  
Underwater Vehicle ◽  
Phase Iii
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