8th international charr symposium c&r
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The document discusses a study on the use of catch and release (C&R) as a fishery management method for Arctic charr in Eyjafjarðará, Iceland. Over 1,500 charr were tagged between 2008-2014 to study short-term mortality rates, recapture rates, growth, and migration patterns under a C&R policy. Results showed 0% short-term mortality in cage experiments, a 9.1% recapture rate of tagged fish in the river, and average growth of 4 cm per year. Based on these results, the study concluded that C&R can be considered a feasible fishery management policy for Arctic charr in Eyjafjarðará.
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8th international charr symposium c&r
- 1. 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 2008-2014 By Erlendur Steinar Friðriksson Supervisors PhD Kristinn Pétur Magnússon Guðmundur Kristján Óskarsson School of Business and Science, Faculty of Natural Resource Sciences University of Akureyri 8TH INTERNATIONAL CHARR SYMPOSIUM 14 -18 JUNE 2015 TROMSØ, NORWAY
- 2. Bleikja (Salvelinus alpinus) 15.6.2015ElliSteinar@gmail.com 2 • Arctic Charr stocks declining • Increasing fishing effort • Fishing numbers going down • Collapse in Eyjafjarðará (Guðni, 2014a; Statistics Norway, 2014)
- 3. Why and what to do? 15.6.2015ElliSteinar@gmail.com 3 • 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
- 4. 15.6.2015ElliSteinar@gmail.com 4 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 + released Commercial 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
- 5. The area.. 15.6.2015ElliSteinar@gmail.com 5 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)
- 6. The river Eyjafjarðará 15.6.2015ElliSteinar@gmail.com 6 Unstable system Large catchment area Runoff, glacier and springfed Cold, 0-12°C Not fertile <25 S/cm Average run sep-apr 25 m3/s Floods, mai-juli 100 m3/s Melting snow from heavy snow area Passable for fish 60 km Tributaries passable for fish 24 km, some very good for spawning and nursing grounds
- 8. 15.6.2015ElliSteinar@gmail.com 8 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 them All icelandic fish-tags: IS-xxxxxx
- 9. • 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 15.6.2015ElliSteinar@gmail.com 9 Results
- 10. „Can catch & release (C&R) be considered as a feasible fishery management policy of charr in Eyjafjarðará?„ 15.6.2015ElliSteinar@gmail.com 10 YES
- 11. Living proof.. Charr ID: IS-93006 Tagged april 2008 – 41 cm Recaptured 2011 – 65 cm ReRecaptured 2014 – 71 cm 15.6.2015ElliSteinar@gmail.com 11
- 12. 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 15.6.2015ElliSteinar@gmail.com 12
- 15. Results - Eyjafjarðará 15.6.2015ElliSteinar@gmail.com 15 P=0,137
Editor's Notes
- Arctic Charr stocks are declining worldwide, but at the same time fishing effort by angling is increasing. In Eyjafjarðará in Iceland fishing effort for charr increased steadily until 2001, followed by a collapse in the stock next years.
- The aim of this study was to investigate the effects and potential C&R for management of charr in Eyjafjarðará in Iceland The study was carried out by (rod-)capturing, tagging and releasing charr, and documenting it´s recaptures For comparison, several other rivers, rod caught salmon and trout, and fish captured by a net of Eyjafjarðará were documented Charr was also captured, tagged, and stored in a cage for two days and mortality calculated Afli er talinn sá fiskur sem hefur verið drepinn en veiði (sbr. veiðitölur) er allur veiddur fiskur, hvort heldur hann er drepinn eða honum er sleppt. Almennt er talið að auknar fiskveiðar (afli) hafi áhrif á stofnstærðir fiskistofna (Ocean Studies Board, 1999). Áhersla í veiðistjórnun, rannsóknum á fiskistofnum og áhrifum veiða á þá, hefur að mestu verið á stofna þar sem að atvinnuveiðar (nytjaveiðar) eru stundaðar (Pauly et al., 2002). Í seinni tíð hefur sókn í sportveiðar á heimsvísu vaxið gríðarlega og er líklegt, samkvæmt varfærnu mati, að heildar sportveiðar geti numið allt að 30 milljón tonnum árlega (Arlinghaus et al., 2007; Ditton et al., 2002). Það nálgast þriðjung af heildar fiskveiðum heimsins, hin síðustu ár (FAO, Fisheries and Aquaculture Department, 2012). Cooke og Cowx (Cooke & Cowx, 2004) mátu hinsvegar, árið 2003, umfang stangveiða á alheimsvísu sem 12 % af heildar afla fiskjar í heiminum og að árlegur fjöldi stangveiddra fiska gæti verið 47 milljarðar og þar af væru 17 milljarðar drepnir eða um 1/3. Tökustöðum fisks má skipa í innri; sem eru kok, tálknbogar eða gómur og ytri; sem eru kjaftvik, augu eða búkur. Mikill munur getur verið veiðidauða eftir því hvort um innri eða ytri tökustaði er ræða. Í rannsókn á vatnableikju (Salvelinus namaycush) mældist veiðidauði vegna töku á innri stöðum vera 71% en vegna töku í kjaftviki (ytri) var veiðidauðinn 7% (Loftus, Taylor, & Keller, 1988). Fiskur tekur yfirleitt flugu eða spún í kjaftvik en gleypir lifandi beitu. Því festist krókurinn á lifandi beitu dýpra í gininu og jafnvel ofan í hálsi og getur þar skaðað tálkn ofl. auk þess sem lengri tíma tekur að losa beitukróka úr skolti (Siewert & Cave, 1990). Í rannsókn á veiðidauða á laxi eftir agni, reyndist veiðidauðinn vera 35% hjá laxi veiddum á maðk en 4% hjá laxi veiddum á flugu (Warner & Johnson, 1978). Því er mælt með að veiðimenn í V&S noti flugu eða spún með agnhaldslausum krókum en ekki beitu. Fimm viðmið: Lágmarka löndunartíma Lágmarka loftun, eða þann tíma sem fiskur er upp úr vatni Forðast veiðar þegar vatnshiti er óvenju hár/lágur Nota agnhaldslausa króka og einungis flugu eða spún Halda veiðum á hrygningartíma í lágmarki Talsvert rannsakað, lax og regnbogi Lifun nálgast 100 % við bestu aðstæður Hlutfall V&S var 59% í BNA árið 1999 Algengara í hægvaxta stofnum og/eða þar sem einstaklingar eru fáir og stórir
- Results showed small differences in the recapture of charr in Eyjafjarðará, whether it was captured and marked by angling or in net. There was no measurable difference in the recapture of charr in Eyjafjarðará in terms of fish size when cought, time of season, angler or between years. No mortalities were detected in charr first 48 hours after capture and tagging. Catch & release can be considered as a feasable fishery management policy of charr in Eyjafjarðará.
- Angling method, Angler, Fish length, Time of year