The impact of electronic monitoring on fleet wide discarding of small cod in Scottish demersal fisheries

Helen Holah*, C. Tara Marshall, Coby Needle, Rob Fryer

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


In Europe, uptake of electronic monitoring (EM) has been hindered by a lack of potential cost savings, given low existing observer coverage, and resistance from industry to greater enforcement of the landing obligation. To assess why certain vessels volunteer for EM and what their subsequent changes in behaviour tell us about those of the wider fleet over time, this study investigates effects of EM on discarding of North Sea cod by Scottish demersal trawlers. As discard data were limited, weight of small cod (grade 5) landed per trip was selected as an indicator of discarding and modelled to describe discard patterns from 2006 to 2016 encompassing the EM-verified cod quota management scheme (2010-2016). Findings show that EM leads to reduced instances of discarding of small cod by participants. However, evidence suggests non-participant vessels were driven to greater levels of discarding due to quota acquisition by participants. Vessels volunteering for EM trials were not predisposed towards greater compliance. Landings data do not support the trial objective of incentivising avoidance of small cod being met. The influence of participants on non-participants has implications for how vessels are selected, and management of behavioural adaptions required to ensure participants remain representative of the wider fleet.

Original languageEnglish
Article numberfsac105
Number of pages12
JournalICES Journal of Marine Science
Issue number6
Early online date29 Jun 2022
Publication statusPublished - Aug 2022


  • catch data
  • discard ban
  • discarding
  • electronic monitoring
  • fully documented fisheries
  • Gadus morhua
  • L
  • BIAS
  • SEA


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