Toskur og hýsa á innaru leiðum – endalig frágreiðing

Translated title of the contribution: Size distribution of cod and haddock in nearshore areas at the Faroes – final report

Petur Steingrund, Sigvald Kristiansen

Research output: Other contribution

Abstract

Í 2010-2011 var nógvur smáfiskur í veiðini hjá út­róðrar­bátum og øðrum, sum royndu á føroyska land­grunn­i­num. Økir nær landi og tveir kassar longri útiá vórðu friðað fyri vinnu­lig­ari línu­veiðu frá juli 2011 til 31. august 2013 (Kunn­gerð nr. 94 frá 4/7-2011) fyri at verja hendan fisk í einum átaki at fáa toska­stovnin aftur á føtur. Útróðrarmenn vóru ikki samd­ir í hes­um friðing­­um og førdu fram, at tann smái fiskur­in fekst ikki við línu í sama mun inni við land sum uttan­fyri. Fiskivinnu­gransking fíggjaðu verk­ætlan­ina „Toskur og hýsa á innaru leiðum”, har Havstovan og útróðrar­menn sam­starv­aðu um at fáa hag­tals­tilfar til vega, sum kundi geva upp­lýsing­ar um nøgdir­nar av smá­fiski inni við land og útiá. Úrslit­ini eru saman­fatað í hesum riti og vísa, at nøgdin av ung­fiski í línu­veiðini var minni í tí stongda økinum nær landi, og at tað eisini var minni av heilt stórum toski. Økið norður-vestur úr Myki­nesi, sum eisini var friðað, hevði nærum somu nøgd av smá­fiski sum uttara økið. Úrslit­ini vístu eisini, at hýsan inni við land í tí stongda øki­num var mun­andi størri enn uttan­fyri.
Trupult er at ávísa ávirkanina av stongdum leiðum, tí eingin veit, hvat hevði hent, um leiðirnar ikki vórðu frið­aðar. Ávirkanin av økisfriðingunum á fiski­deyðan hjá smá­fiski (aldur 2-4 ár) var torfør at ávísa. Hóast fiski­deyðin var lítil í friðingar­tíðini, kundi tað eins væl komast av teirri lítlu til­gongd­ini av smá­fiski (2 ára gamal), tvs. tí lítla áhuga­num hjá fólki at fara á flot, tá einki var at fáa. Ávirkan­in av økis­friðing­unum á yvir­living (til­gongd) hjá smá­fiski var eisini tor­før at ávísa. Tá ein saman­ber ta veru­ligu til­gongd­ina við væntaðu til­gongd­ina (út frá ein­um sam­bandi um, at toskur etur tosk) bendi einki á nakra á­virkan av teim­um stongd­u økjunum á til­gongd­ina í 2011-13, hóast betri tøl verða tøk um um­leið trý ár. Hin­vegin var til­gongd­in í 2010 (2008 ár­gang­ur­in, sum var høvuðs­orsøk­in til friðing­ar­nar) størri enn væntað, og kann vera eitt úrslit av friðing­unum, hóast tað eru aðrir møgu­leikar. Magnus Heinason fekk nógvan smá­fisk í september 2013, og kann tað vera eitt úrslit av friðing­unum.
Friðingar í framtíðini av smáfiski kunna vera gjørd­ar við at friða økir út frá landi. Tað kundi verið tey tvey økini, sum vóru við í friðing­unum (norður-vestur úr Mykinesi og eystur úr Fugloy) og møguliga onnur økir, til dømis eystan fyri Sandoy. Ein for­treyt í slík­um friðing­um má vera, at økini eru stongd fyri allari veiðu (tó við á­vís­um eyð­sýnd­um undan­tøk­um), og ikki, sum gjørt varð fyri økið nær landi, við at friða fyri ávísar skipa­bólkar (útróðrar­bátar á vinnulig­ari línu­veiðu). Vitandi um, at hýsu­stovn­ur­in eisini plagar at vera illa fyri, tá toska­stovn­ur­in er illa fyri, eiga frið­ing­ar av smá­fiska­leið­um at sam­skip­ast við møgulig­ar friðing­ar av hýsu­leið­um. Um tað koma sterkir ár­gangir av toski, eigur kort­ini møgu­leiki at vera fyri at friða økir nær landi, um tað kann á­vísast, at nógvir ikki-vinnulig­ir bátar leggjast á at fiska smá­fisk.
Niðurstøðurnar frá verkætlanini eru tí hesar:
1) Økini nær landi vóru ikki betur egnað til at verja ungfisk enn onnur økir longur út frá landi.
2) Ávirkanin av teimum stongdu økjunum á veiði­trýst og yvir­living hjá smá­fiski var tor­før at á­vísa vegna tess, at eingin veit, hvat hevði hent, um leiðir­nar ikki vórðu friðaðar. Tó eru á­bending­ar um, at 2008 ár­gang­ur­in fekk nyttu av friðing­unum.
3) Framtíðar friðingar av smáfiski kunnu gerast við at friða økir út frá landi (fyri allari veiðu) og sam­skip­ast við møgulig­ar friðing­ar av hýsu­leið­um. Um sterkir árgangir av toski koma, eigur møgu­leiki at vera fyri at friða økir nær landi.

In the period 2010-2011 juvenile cod were frequent­ly caught in the longline and jigging fishery at the Faroes. All areas close to land and two areas further from land were closed to commercial long­line fishery from July 2011 to 31. August 2013 (Announce­ment no. 94 dated 4. July 2011) to protect these juvenile fish in an attempt to boost the already decimated cod stock. Longline fisher­men disagreed and claimed that more juvenile cod were found further from land. The fond “Fiskivinnu­gransking” funded a project “Cod and haddock in nearshore areas at the Faroes”, where Faroe Marine Research Institute and fishermen cooperated to get data, which could resolve this issue. The results showed that the relative amounts of juvenile cod were lower close to land than further out, but that very large cod also were scarcer close to land. Haddock close to land were much larger than haddock further out from land.
It is methodically difficult to demonstrate the effect of area closures, because it is unknown what had happened if the areas were not closed. The effect of the area closures on the fishing mortality of juvenile/small cod (age 2-4 years old) was difficult to demonstrate. Although the fishing mortality was low during the closure period, it was equally well explained by the low recruitment of 2 year-old cod, i.e., the tendency of people to go fishing when there were good catches close to land. The effect of the area closures on the juvenile survival (recruitment) was also difficult to demonstrate. Comparing the observed recruitment with the expected recruitment (based on a model of cannibalism) indicated no effect of the closed areas on the recruitment in 2011-13, although better estimates will be available in about three years. However, the recruitment in 2010 (the 2008 year class, which was a main reason to close the areas) was higher than expected, and could be a result of the area closures, although there are alternative explanations. The research vessel “Magnus Heinason” got many juvenile cod in September 2013, which could be a result of the area closures.
Future area closures to protect juvenile cod could be done by closing areas out from land. Candidates could be the two areas already included in the closures (north-west of Mykines and east of Fugloy) and probably other areas as well, for example east of Sandoy. A prerequisite for such area closures must be that they are closed for all fishing (with obvious exceptions), and not, as done for the area close to land, by restricting only certain fleets (commercial longline boats). Knowing that the had­dock stock usually is in a poor state at the same time as the cod stock, the area closures for juvenile cod aught to be coordinated with future area closures of haddock grounds. Nevertheless, in the case of strong incoming year classes of cod, the possibility to close areas close to land should be kept open if it can be demonstrated that juvenile cod suffer excessive fishing mortality as a result of numerous un-commercial boats targeting juvenile cod.
Hence, the conclusions from the project are:
1) The areas close to land were not better suited to protect juvenile cod compared with other areas further out from land.
2) The effects of the closed areas on the fishing mortality and recruitment of juvenile cod were difficult to demonstrate due to methodical problems (it is unknown what had happened if the areas were not closed). However, the 2008 year-class probably benefited from the area closures.
3) Future area closures to protect juvenile cod could be done by closing areas out from land (for all fishing) and coordinated with potential area closures of haddock grounds. In case of strong incoming year classes of cod, the possi­bility should be kept open to close areas close to land.
Translated title of the contributionSize distribution of cod and haddock in nearshore areas at the Faroes – final report
Original languageFaroese
TypeHavstovan Technical Report
PublisherHavstovan - Faroe Marine Research Institute
Number of pages14
Place of PublicationTórshavn
Edition14
Volume13
Publication statusPublished - Dec 2013

Publication series

NameHavstovan Technical Reports

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