Acoustic seabed classification of marine habitats: studies in the western coastal-shelf area of Portugal

Freitas, Rosa; Silva, Susana; Quintino, Victor; Rodrigues, Ana María; Rhynas, Karl; Collins, W.T.

doi:10.1016/s1054-3139(03)00061-4

Cited by 49 publications

(22 citation statements)

References 11 publications

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“…These are essentially used as a framework within which reference sites are defined. Samples of in situ data are then collected from all the detected regions, or the reference sites, so as to validate the classified habitats (see Brown et al 2002;Freitas et al 2003;Jordan et al 2005;Kloser et al 2001;Kostylev et al 2001), and classes are occasionally merged if they can be proven to have non-distinct faunas.…”

Section: Approachesmentioning

confidence: 99%

See 1 more Smart Citation

Seabed Mapping and Marine Spatial Planning: A Case Study from a Swedish Marine Protected Area

Gonzalez-Mirelis¹,

Lundälv²,

Jonsson³

et al. 2012

Marine Ecosystems

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Section: Approachesmentioning

confidence: 99%

“…But the more gradual changes, which may emerge in response to factors other than substrate, are wholly overlooked. A more serious issue is that assemblages may be identified from the in situ data which have no corresponding acoustic class (Freitas et al, 2003). In fact, this is, according to Brown et al (2005), to be expected.…”

Section: Approachesmentioning

confidence: 99%

Seabed Mapping and Marine Spatial Planning: A Case Study from a Swedish Marine Protected Area

Gonzalez-Mirelis¹,

Lundälv²,

Jonsson³

et al. 2012

Marine Ecosystems

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“…Normalizing the echosounder waveforms to a reference depth allows signal sampling to correspond to a standard set of incidence angles, as opposed to a set of linearly spaced time (Caughey et al 1994). The navigation system, connected to both the echosounder and the QTC VIEW system, was a Differential Global Positioning System (DGPS), providing position accuracy of ±1 m. The acoustic system QTC VIEW series V achieves faster digitization of the signal with a better resolution and dynamic range (Freitas et al 2003b(Freitas et al , 2008 and permits classification over a depth range that includes very shallow waters, according to the manufacturer. The collected data were then used through QTC IMPACT to create a catalogue of known seabed classes (Freitas et al 2003b).…”

Section: Field Surveymentioning

confidence: 99%

Estuarine Habitat Assessment for Construction of a Submarine Transmission Line

Hamouda

Abdelsalam

2010

Surv Geophys

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The present paper describes a submarine survey using the acoustic discrimination system QTC VIEW (Series V) as an exploratory tool to adjust final route alignment of a new pipeline. By using acoustic sound survey as an exploratory tool described in this paper to adjust final route alignment of a new pipeline to minimize the environmental impact caused and ultimately to avoid any mitigation measures. The transmission pipeline extended from the shore line of Abu-Qir Bay, on the Mediterranean Sea in Egypt, out to 70 nautical miles at sea (60 m water depth). Four main surface sediment types were defined in the study area, namely fine sand, silty sand, silt and clay. Results of the acoustic classification revealed four acoustic classes. The first acoustic class corresponded to fine sand, absence of shell debris and very poor habitats characteristics. The second acoustic class is predominant in the study area and corresponds to the region occupied by silt. It is also characterized by intermediate diversity of macrobenthic invertebrate community which is mainly characterized by polychaeta. The third acoustic class is characterized by silt to silty clay. It is characterized by a high diversity of macrobenthic invertebrate community which is mainly polychaeta with an intermediate diversity of gastropoda and bivalvia. The final acoustic class is characterized by clay and high occurrence of shell debris of gastropoda, bivalvia and polychaeta.

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“…Unsupervised classifications of the acoustic data were conducted for each of the eight data sets. The number of unsupervised classes was determined by the lowest total score of the three axes based on k-means partitioning using an iterative process (Freitas et al, 2003;Preston and Kirlin, 2003).…”

Section: Capelin Spawningmentioning

confidence: 99%

An ecosystem-based research program for capelin (Mallotus villosus) in the northwest Atlantic: overview and results

Davoren¹,

May²,

Penton³

et al. 2007

J. Northw. Atl. Fish. Sci.

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The Northwest Atlantic has been undergoing extensive ecosystem shifts involving oceanographic change and over-fishing. Capelin (Mallotus villosus), the focal forage fish species in this system, is a primary prey for most large predators, including cod, seals, whales and seabirds. Recently, the biology and behaviour of capelin has changed dramatically, although the basis for these changes is not well understood. Through a collaborative, multi-disciplinary research program among university, government and commercial fishers, we investigated mechanisms underlying these changes. In this manuscript we present an integrated overview of this initiative and synthesize key results from research carried out within the program. Our meso-scale study area encompassed the Funk Island Seabird Ecological Reserve, situated 60 km northeast of the Newfoundland coast. We identified 11 off-beach demersal spawning sites of capelin, which were primarily associated with small gravel in bathymetric depressions where temperatures were >2°C. Through comparisons of beach and demersal spawning, we described two distinct developmental strategies of eggs: high mortality and rapid development for beach sites versus low mortality and slow development for demersal sites. Emergence strategies of larvae at demersal sites also differed from beach sites elsewhere in Newfoundland. Integrating results from vessel-based and moored hydroacoustics (Acoustic Doppler Current Profilers) and biological sampling suggested that the diel vertical migratory patterns of capelin and its zooplankton prey are related. Capelin >120 mm total length migrated with larger, longer-distance (0-300 m) crustacean migrators (amphipods, euphausiids), whereas capelin <120 mm migrated with smaller, shorter-distance (0-100 m) migrators (copepods). These patterns influenced the diurnal feeding patterns of top predators. Vessel-based measures of observed seabird distributional patterns and trawl-estimated capelin availability and colony-based measures of seabird diets J. Northw. Atl. Fish. Sci., 39: 35-48. doi:10.2960/J.v39.m595 http://journal.nafo.int J. Northw. Atl. Fish. Sci., Vol. 39, 2008 36 revealed that seabirds are selective in their pursuit of forage prey and that they expand their foraging ranges considerably when capelin were less available in certain years. Furthermore, changes in the dietary composition of common murre (Uria aalge) can be linked to changes in the availability of capelin >100 mm, suggesting that the diet of common murre, and perhaps of other seabirds, has the potential for becoming a quantitative indicator of capelin status. Overall, this type of research framework will be important for moving toward ecosystem-based management approaches.

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Acoustic seabed classification of marine habitats: studies in the western coastal-shelf area of Portugal

Cited by 49 publications

References 11 publications

Seabed Mapping and Marine Spatial Planning: A Case Study from a Swedish Marine Protected Area

Seabed Mapping and Marine Spatial Planning: A Case Study from a Swedish Marine Protected Area

Estuarine Habitat Assessment for Construction of a Submarine Transmission Line

An ecosystem-based research program for capelin (Mallotus villosus) in the northwest Atlantic: overview and results

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