Download - 8th international charr symposium c&r
Arctic Charr fishery management Catch and release in Eyjafjarðará, Iceland
Erlendur Steinar Friðriksson
Elli Steinar
Based on Magister Scientiarum degree thesis in Natural Resource Sciences
2008-2014By Erlendur Steinar Friðriksson
SupervisorsPhD Kristinn Pétur MagnússonGuðmundur Kristján Óskarsson
School of Business and Science, Faculty of Natural Resource Sciences
University of Akureyri
8TH INTERNATIONAL CHARR SYMPOSIUM14 -18 JUNE 2015
TROMSØ, NORWAY
2
Bleikja (Salvelinus alpinus)
• Arctic Charr stocks declining• Increasing fishing effort• Fishing numbers going down• Collapse in Eyjafjarðará
(Guðni, 2014a; Statistics Norway, 2014)
Why and what to do?
• Find out why the stocks af charr are declining• Remove fishing mortality out of the equation
• The goal of catch and release (C&R) as fishery management method is to reduce mortality due to fishing by releasing cought fish, alive back to the water
• The method has been applied for many years with a decent performance in a variety of sport fish species, including salmon and trout
• 2008 - Fishing management changed to C&R – tributaries closed for fishing
• Little documentation, however, was found for C&R beeing used for the charr fishery management
• So there was also a need for research on the effects of C&R
[email protected] 415.6.2015
Recreational fishing - 30% of world total catch
Catch & release - 30% of total angling
„Can catch & release (C&R) be considered as a feasible fishery management policy of charr in Eyjafjarðará?„
Use the method af tag and recapture
Catch= landed + releasedCommercial v.s. Recreational - Different approach
Explore:• Mortality• Recapture– By river, angling method, angler, fish size, time of season
• Data also used to estimate:– Migration, growth, mortality and stocksize
• Flyfishing only
The area..
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30-40% of all searun Charr in Iceland ?
(Jørgensen & Johnsen, 2013)
• 1504 tagged 184 cought in net
• Charr 1194 / 830• Salmon 64 / 1• Trout 230 / 87• (Total / Eyjafjarðará)
The riverEyjafjarðará
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Unstable systemLarge catchment areaRunoff, glacier and springfedCold, 0-12°CNot fertile <25 S/cmAverage run sep-apr 25 m3/sFloods, mai-juli 100 m3/sMelting snow from heavy snow areaPassable for fish 60 kmTributaries passable for fish 24 km, some very good for spawning and nursing grounds
[email protected] 715.6.2015
[email protected] 815.6.2015
Anchor tag, Floy tag or T-bar anchor tags. Each tag has an ID-number, => each tagged fish has an ID Directorate of Fisheries allocates themAll icelandic fish-tags: IS-xxxxxx
• Short term mortality (48h - cage expirement)? 0%• Recapture? 9,1%• Difference in recapture by;
– Angling method? Not confirmed– Angler? Not confirmed– Fish length? Not confirmed– Time of year? Not confirmed
• All recaptures in same river as tagged or at sea• 83 recaptured charr in Eyjafjarðará;
37, 29, 13, 4 in year 0,1,2,3 respectively• Average growth: 4 cm/year
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Results
„Can catch & release (C&R) be considered as a feasible fishery management policy of charr in Eyjafjarðará?„
15.6.2015
YES
Living proof..
Charr ID: IS-93006
Tagged april 2008 – 41 cm
Recaptured 2011 – 65 cm
ReRecaptured 2014 – 71 cm
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Disscussion and further research
• 9,1% recapture?– Supports C&R fishery management – Higher survival? - Study further with radiotagges– Recalculate catch („correct“ the numbers)
• Short term mortality 0%– Supports C&R fishery management
• Difference in recapture by:– Angling method, angler, fish length, time of year
• Fishing rate and stock size?– Further tagging and installation af a fish counter
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[email protected] 1415.6.2015
