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Multibeam Sonar Mapping and Scallop Stock Assessment: GIS Data Integration in Support of Sustainable Fisheries Management. Gerry Sutton O.Tully, J. Hickey: BIM A. Hervas:TCD X. Monteys: GSI. Project Overview. BIM-Main project 2002-2004 ( MBES surveying commenced in 2001 )
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Multibeam Sonar Mapping and Scallop Stock Assessment:GIS Data Integration in Support of Sustainable Fisheries Management Gerry Sutton O.Tully, J. Hickey: BIM A. Hervas:TCD X. Monteys: GSI
Project Overview • BIM-Main project 2002-2004 • (MBES surveying commenced in 2001) • Main objectives: • To provide key info for fisheries development and management • Stock levels assessment • Physical and environmental controls on recruitment HYDRO-04
Scallop Project –Main Elements • Application of biological stock assessment models-sampling program (TCD/Kilmore Coop) • Sedimentary characterisation and ID beds (CMRC) • Fine resolution hydrodynamic model-tidal/larval circulation (MARCON) HYDRO-04
Background to Mapping Programme • Early US/Canadian programs based on water depth or commercial effort- crude sediment maps only • Scallop preference for sand/gravel • MBES surveys revealed sediment heterogeneity • The work of Kostylev et al (2001) suggested: • strong influence of sediment type on scallop distribution • scallop abundance and fishing success can be predicted from multibeam backscatter data HYDRO-04
Mapping program main elements • High resolution mapping of seabed morphology and sedimentary facies in scallop grounds • Determine and refine bs/stock density correlation • Determine high abundance areas within known grounds • Apply results in new areas HYDRO-04
To date: • MBES coverage-Bathy/BS • complex heterogenous seabed characterised by smallsand and gravel waves and elongate well organised dune-like bedforms • Two dominant acoustic facies sediment types clearly visible • Concept proved: confirmed sharp correlation between bs and stock density • Other aspects are far advanced e.g: HYDRO-04
Sled mounted U/W video camera was towed across seabed to collect continuous imagery throughout 1km transects within a representative selection of sediment facies throughout study area. Video signals were encoded with DGPS allowing video image position to be accurately overlain and correlated with seabed facies maps
Conclusions • EM 1002 data is more than adequate for bathy and habitat/biotope mapping-NB operator settings critical for BS not just sounding • Near offshore Ireland tidal model needs to be resolved • Strong MBES BS/Scallop relationship exists for this stock/area • MBES BS predictive for fishing success • High degree of heterogeneity in sediments both PS and rugosity-complex range of bedforms even in uniform area • Sediment samples relatively poor GT alone • High resolution video v.useful/required for GT • Powerfull integration/visualisation tools required • Seabed classification technology has arrived but NBB GT/Slopes/Operator Settings HYDRO-04
Acknowledgments • BIM-NDP • Kilmore Fishermans Co-op-skippers/crews • Marine Institute-All vessel ops team and crews, • MI-Fisheries-Colm Lordan-UW video • GSI-NSS team • BlueGlen-Tim McCarthy • CMRC-Volunteers! HYDRO-04