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It's Too Easy Being Green: Using Underwater Video to Optimize Capture Efficiency of Invasive Green Crab to Reduce their Impact on Fisheries

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    Brett Favaro Memorial University

European green crab (Carcinus maenas) are notorious invaders on the Atlantic and Pacific coasts of Canada.

There were some surprising findings in year 1, which have prompted the addition of two major research dimensions for the second year. One open question is, how quickly green crabs affect eelgrass habitat post-invasion? To answer this, an autonomous drone was purchased, which will be used to rapidly assess eelgrass coverage in pre-invaded sites, where other research has suggested green crab are likely to invade in the near future. In addition, scuba-based fieldwork is gearing up in the second field season.

The first major accomplishment of the two HQP on this project (Jonathan Bergshoeff and Nicola Zargarpour) was designing and constructing the underwater camera apparatus that has underpinned all aspects of this project. A detailed methods paper is currently being written. The components for the underwater housing cost <$40 - therefore, this technique could have major implications for marine biology research in shallow water environments. The first videos of green crabs in and around Fukui and lobster traps was collected. Now that the field methodology is proven, plans are being made for the second year of fieldwork.

In the meantime, publications based on the results of the first year of fieldwork have been prepared and presentations have been given at two industry meetings on the topic.


  • Fisheries and Oceans Canada - NL


  • Kiley Best Memorial University
  • Cynthia McKenzie Fisheries and Oceans Canada


  • Jonathan Bergshoeff Memorial University of Newfoundland
  • Nicola Zargarpour Memorial University of Newfoundland


  • Bergshoeff,Jonathan,Favaro,Brett,Zargarpour,Nicola,Legge, G. 2017, How to build a low-cost underwater camera housing for aquatic research, FACETS 2, 2: 150-159,10.1139/facets-2016-0048.
  • Bergshoeff,Jonathan,Best,Kiley,Favaro,Brett,McKenzie,Cynthia,Zargarpour,Nicola,. 2016, Using underwater video to optimize capture efficiency of invasive green crab (Carcinus maenas) to reduce their impact on fisheries., CSAR Technical Report, P-468, 1-45.,
  • Favaro,Brett,Meintzer, P., Walsh, P.. 2017, Will you swim into my parlour? In situ observations of Atlantic cod (Gadus morhua) interactions with baited pots, with implications for gear design., PeerJ 5, e2953,

Our first goal is to create more efficient green crab removal programs, tailored to the needs of environments around Newfoundland. Second, we will develop an understanding of why green crabs depress lobster catch, and potential pathways for reducing these effects in invaded systems. Fishers and managers will be the primary beneficiaries of this work, which will ultimately improve our ability to maintain the integrity of the marine environment.

Follow Brett Favaro on Twitter: @LetsFishSmarter

Spying on invading European green crab - Navigator Magazine, Issue 11