Intro to BE individual project

1. IMPROVING THE EFFICIENCY OF
THE FUKUI TRAP AS A CAPTURE
TOOL FOR THE INVASIVE
EUROPEAN GREEN CRAB
Presentation by: Wesley Cagle
Based on a Research article by : Jonathan A.
Bergshoeff , Cynthia H. McKenzie, and Brett Favaro

2. INTRODUCTION
• What is the European green crab? (Pictured upper right)
• Invasive species from Atlantic coast of Europe
• Destroy eelgrass beds, prey on native bivalves,
compete with native species like Rock crab (pictured lower right)
• Grow up to 10 cm across and can spawn up to 185,000 eggs per year
• Fukui traps (pictured lower left) had been used to capture green crabs
previously

3. OBJECTIVE
• Main objective from article: “to improve the
performance of the Fukui trap as a capture tool
for green crabs.”
• Plan to reach objective by designing modified
Fukui traps
• Based modifications on previous study where
wild crab and Fukui trap interactions were
filmed

4. METHODS
• Developed four distinct trap
modifications (widest opening)
• Sinker: Three weights were added to
bottom of opening (2 cm)
• Mesh: Mesh screen was added to trap
entrance for more traction(0 cm)
• Assist: Mesh screen strip added past
opening for grip(0 cm)
• String: the top and bottom of opening
held open by strings(6 cm)

5. METHODS
• Experiment conducted in Fox Harbour and North
Harbour, Newfoundland and Labrador
• Ran from June to August of 2016
• Set traps in groups of 5, one of each modified and
one unmodified trap, spaced 10 m
• Baited with cut Herring in perforated plastic bait
container
• Green crabs were
kept to be counted,
sexed, and measured,
all bycatch were
recorded and released

6. RESULTS-BYCATCH
• A total of 17,615 green crabs were captured across 520 trap
deployments
• 174 total bycatch captured including 157 rock crabs

7. RESULTS-TRAP TYPE
• All relative to the standard Fukui trap:
• Mesh, Sinker, and Assist modified traps all saw
increased catch rates
• String modified traps did not show a statistically
significant improvement over the control
• Sinker and string modifications caught larger male
green crabs

8. DISCUSSION-TRAP TYPE
• String modified traps: Least effective in capturing, suspected high
frequency of escapes, easy to install but difficult to empty
• Mesh modified traps: 29% increase in catch, time consuming to
implement
• Sinker modified traps: 59% increase in catch, easiest implemented, most
durable, easily emptied, most effective for large scale
• Assist modified traps: 81% increase in catch, time consuming to install,
lacked durability

9. DISCUSSION-BYCATCH
• All Fukui traps, modified or not, produce very limited bycatch
• The design modifications were made to facilitate crab entry and retention,
which can extend into non-target species
• Traps and pots in general more selective with higher live release rates of
bycatch
• In Sinker modified traps, the mean bycatch rate was .423 bycatch per
deployment

10. CONCLUSION
• Set out to make modifications to the Fukui trap that were simple,
durable, and effective at increasing catch rate
• The sinker modification was found to be the best at meeting these
requirements and has the most potential for widescale use
• The assist modification is great for improved catch rate but needs durability
improvements
• Modifications should be tested in new regions before application
Green crab found on San Juan Island,
Washington state
Green crab caught off the coast of
New Hampshire

11. REFERENCES
Article
• Bergshoeff JA, McKenzie CH, Favaro B. 2019. Improving the efficiency of the Fukui trap as a capture tool for the invasive European green crab
(Carcinus maenas) in Newfoundland, Canada. PeerJ 7:e6308
Images (In order, graphs and tables from article not included)
• https://www.incimages.com/uploaded_files/image/1940x900/getty_515741103_200013351818843106229_new_359310.jpg
• https://reefnation.com/wp-content/uploads/2016/05/Screen-shot-2016-05-24-at-3.27.39-PM.png
• http://www.nlnature.com/observations/827/DSC05969.JPG
• https://dfzljdn9uc3pi.cloudfront.net/2018/4223/1/fig-5-full.png
• http://www.nfl.dfo-mpo.gc.ca/folios/00250/images/green_crab_2.jpg
• http://uhbiology.kahikai.org/?p=1500
• https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSdnAMRSVBaDD4A7oEiBz2EkPKnPzgBSrHGg8bG5auVfS5fTb01qA
• http://3.bp.blogspot.com/-g4YhSkwMT7Y/T0qLgBsEo9I/AAAAAAAAABw/1DORdLD9s4o/s1600/Wanted+European+Green+Crab.jpg
• http://www.iucngisd.org/gisd/species.php?sc=114
• https://wsg.washington.edu/crabteam/greencrab/id/
Addition information
• https://reefnation.com/invasive-european-green-crab/
• https://www.fishaq.gov.nl.ca/research_development/fdp/pdf/rock_crab.pdf

12. QUESTIONS?