The document summarizes a seabed survey of the Aran Grounds area conducted in 2009. It provides background on the Nephrops fishery in the area. It describes the acquisition of multibeam acoustic and geophysical data from 2005-2009. Results from 2009 include shaded relief and backscatter imagery identifying areas of fine sandy mud, gravel lag, and bedrock. Future work involves sub-bottom profiling to interpret sediment layers and producing a 3D model of the mud layer that is habitat for Nephrops.

1. Aran Grounds Seabed Survey 2009
Cathal Clarke
Advanced Mapping Services (AMS) Bursary

2. Presentation Outline
• Background of the Aran Grounds Nephrops Fishery
• Multibeam Acoustic Data Acquisition
• Geophysical Data Acquisition 2005 – 2009 Overview
• 2009 Current Results
• Four weeks down, Four to go – Where next?

3. Background of the Aran Grounds Nephrops Fishery
Nephrops norvegicus (AKA: Dublin Bay
King Prawn, Scampi or Langouistine )
Irish Sea
Aran Grounds
Smalls
2005 Nephrops Catch weight (Kg/ nMi²)

4. 0.00 0.00 0.00 0.18 1.27 1.06
1.31 0.95 0.78 0.79 0.00 0.00
5860000
Nephrops Density
1.41 1.30 0.00 0.00
the Aran Grounds
1.39
Plot Estimates of
0.00 1.20 0.00 0.00 0.00
1.30 1.77 2.02
5855000
Contoured
0.00 0.00 0.00
burrows/ m²
0.00 0.00 0.00 0.00 0.00 0.00
2004
0 425000 430000 435000 440000 445000 450000 410000 415000 420000 425000 430000 435000 440000 445000 450000 455000
Background of the Aran Grounds Nephrops Fishery
0.00 0.00 0.24 0.00
0.14
0.00 0.00 0.00 0.00 0.00 0.00
0.54 0.38 0.61 0.43 0.16 0.00 5890000 2007 0.00 0.84 1.05 0.99 0.32 0.00 0.00 0.00
2.4
2.1
0.64 0.71 1.01 0.99 0.43 0.00 0.00 0.00 0.80 1.18
0.01 0.00 5885000 1.24 0.85 0.46 0.08 0.00 0.00 2
0.97
1.9
1.8
0.69 0.00 0.01 0.26 1.14 0.83 1.14
0.76 0.83 0.75 0.68 0.09 0.06 0.00 1.15 1.25 0.62 0.15 0.02 0.00 1.7
5880000
1.6
?
0.00 0.00 1.13 1.22 1.03 0.97 1.19 1.08 0.54 1.5
0.83 0.76 1.13 0.10 0.12 0.00
0.94 0.87 0.49 0.11 0.00 1.4
5875000 1.3
0.00 0.71 0.97 0.92 0.96 1.21 1.08 1.09 0.86
0.16 0.71 0.20 0.00 1.2
0.75 0.90 0.87 0.83 0.28 1.1
?
0.86 0.91 0.00
5870000 1
0.001.04 0.86 1.09 0.87 1.15 1.04 1.10 1.03 1.12 0.61 0.05 0.00 0.9
0.79 0.95 0.81 0.90 0.03 0.8
0.61 0.95 0.00
58650000.00 0.24 1.01 1.04 1.09 1.02 0.86 0.7
0.72 0.96 0.55 0.07 0.00 0.00 0.6
0.68 0.75 0.66 0.56 0.69 0.05 0.00 0.5
0.4
?
0.00 1.28 1.22 1.00 1.16 1.53 1.44
5860000 0.00 0.00 0.00
?
0.3
0.61 0.73 0.00 0.00 0.00
0.2
0.00
0.00 0.00 1.21 1.05 0.00 0.00 0.1
0
5855000

5. Multibeam Acoustic Data Acquisition

6. Geophysical Data Acquisition 2005 – 2009 Overview
Co. Galway
Co. Clare

7. 2009 Current Results –Shaded Relief

8. 2009 Current Results –Shaded Relief
Fine Sandy Mud etc.
Gravel Lag / Bedrock

9. 2009 Current Results – Backscatter
Low Backscatter
Fine Sandy Mud etc.
High Backscatter
Gravel Lag / Bedrock

10. Four weeks down, Four to go – What next?
Sand → Mud Seadbed
Layered post glacial material
Bedrock Glacial Till

11. Wrapping it up…
To date -
3 Days of Multibeam Data, Cleaned and Processed
Backscatter &Shaded Relief for 80km² of Aran Grounds Seabed
To Come -
Sub Bottom Profile data to interpret & tag
Produce a 3D surface of the mud layer – Home to Nephrops
Thank You;
Project Supervisor: Fabio Sacchetti (Advanced mapping Services)
Multibeam Processing: Fabio/ Vera Quinlan (AMS)
Sub-bottom Profile Processing: Kevin Sheehan (AMS)
GIS Integration: Nicola O’Brien (AMS)
Nephrops Data: Colm Lordan (Fisheries Science Services)

12. Thank You!
For more information on Surveying, Coverage,
Images, Google KMLs & Fly-Throughs,
Visit:
www.infomar.ie