Arrostuto, N.

Uhlmann, S.S.

Verstockt, S.

Open Marine Archive

-  70  -  
Poster Science in a modern era 
Fishing for advantages with on-board electronic monitoring and digital 
image analysis techniques 
Arrostuto Nicola
1
, Verstockt Steven
2
 and Uhlmann Sven Sebastian
3 
1
  Land and Environmental Management Marine Master course, University of Sassari, 07100 Sassari, 
Italy., Sassari, Italy 
E-mail: narrostuto@gmail.com 
2
  Department of Electronics and Information Systems, Ghent University, Technologiepark Zwijnaarde 
19, AA-tower, 9052 Zwijnaarde, Belgium 
3
  Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Ankerstraat 1, 8400 Oostende, 
Oostende, Belgium 
 
The relevance of electronic monitoring (EM) in turning data-poor into data-rich situations and cutting 
costs will become more and more important as a tool for sustainable fisheries management under an 
ecosystem approach. In this study we evaluate the utility of using cameras to a) identify beam-trawled 
rays passing on a sorting conveyor and b) digitally analyze the extent of bleeding on the undersides of 
beam-trawled flatfish. For a), video footage was collected onboard a commercial Belgian beam trawler; 
and for b), photographs were taken from 66 fish of six species sourced from the R/V Simon Stevin while 
beam-trawling in the Belgian coastal zone of the Southern North Sea. A trained reviewer was able to 
correctly identify thornback, undulate and spotted rays, among others, when comparing review record 
counts with on-board observations. For the second part of this study, injuries of interest were visible 
multifocal cutaneous petechiae (termed ‘point bleeding’), and suffusion or haemorrhaging (termed 
‘bruising’). A series of algorithms was developed by students of the University of Ghent to 1) separate 
the fish from the background, 2) align each image and identify the species by raytracing; 3) segment the 
fish into fin, body and head regions (e.g. based on K-means clustering, frequency domain, Gabor filter 
and superpixel techniques); and 4) quantify the surface area of bleeding injury of each region by using 
species-specific thresholding techniques (i.e. hsv hue). For validation, results from the algorithmically 
obtained surface area % were compared to three rater’s average % estimates. By accurately recording 
catches on-board and recording the coverage of externally visible bleeding injury, a device could be 
developed to combine and automate both camera-based techniques to sort any commercial catch and at 
the same time measure quality of whole fish or fillets. Such technological advancements will facilitate 
the transition towards a more sustainable fishery and the implementation of the European landing 
obligation. 
 
Keywords: CCTV camera monitoring; commercial fisheries catches, digital image analysis 
  


Fishing for advantages with on-board electronic monitoring and digital image analysis techniques

http://www.vliz.be/imisdocs/publications/318197.pdf

Fishing for advantages with on-board electronic monitoring and digital image analysis techniques

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