L’eglefino (Melanogrammus aeglefinus) è una delle specie demersali più importanti per i pescatori scozzesi. Le tre riserve del Mare del Nord, della costa occidentale e di Rockall contribuiscono con 37.392 tonnellate agli sbarchi in Scozia, per un valore di 43,8 milioni di sterline. Nella pesca all’eglefino si utilizzano vari tipi di reti a strascico e scorticarie.

La specie è ampiamente diffusa nella acque scozzesi a profondità inferiori ai 200 m. Gli esemplari maturano tra i 2 e i 3 anni di età e si riproducono da febbraio a maggio, deponendo ognuno varie centinaia di migliaia di uova. Generalmente, le larve non si allontanano dalla zona di schiusa, sebbene alcune siano trasportate fino al Mare del Nord, dettaglio che suggerisce una possibile relazione fra queste due popolazioni. I giovani eglefini vivono per un certo tempo in acque superficiali prima di acquisire abitudini demersali. Il tasso di sopravvivenza è molto variabile e il popolamento è caratterizzato da ondate occasionali di un gran numero di esemplari giovani. La dieta varia in base alla disponibilità locale di cibo e alle dimensioni degli esemplari. Una grande varietà di animali che popolano il fondale costituisce una fondamentale risorsa alimentare, e con la crescita dell’eglefino il pesce acquisisce sempre maggiore importanza.

Le valutazioni sono effettuate dal CIEM. La Scozia partecipa ai rilevamenti tramite navi da ricerca coordinate a livello internazionale e contribuisce in massima parte alla campionatura di dati biologici provenienti da mercati ittici e imbarcazioni commerciali.  La biomassa dei riproduttori (SSB, spawning stock biomass) è equivalente o superiore ai livelli precauzionali (Bpa) in tutte e tre le riserve di eglefino, che godono attualmente di piena capacità riproduttiva.  Lungo la costa occidentale, tuttavia, sarà necessario diminuire l’entità del pescato per mantenere le risorse al di sopra dei Bpa . La mortalità alieutica è prossima o al di sotto dei livelli precauzionali (Fpa). Al pari di altre specie demersali catturate in attività ittiche miste, l’eglefino è soggetto alla valutazione del CIEM, che si occupa della salvaguardia delle riserve nelle condizioni più gravi.

Mare del Nord

 

Costa occidentale

 

Rockall

  

In 1999 the EU and Norway agreed to implement a long-term management plan for the [North Sea] haddock stock, which is consistent with the precautionary approach and which is intended to constrain harvesting within safe biological limits (SSB > Blim) and is designed to provide for sustainable fisheries and high potential yield. A revised management plan was implemented in January 2009. The main elements of the plan are a target F of 0.3 with a limit of 15% change in TAC provided SSB is maintained above 140,000 tonnes. If SSB is between 140,000 tonnes and 100,000 tonnes, F is reduced in line with SSB to reach F = 0.1 at SSB = 100,000 tonnes. If SSB is at 100,000 tonnes or below, F is 0.1. Interannual quota flexibility is permitted, with a maximum of 10% transfer of quota between years.

ICES has evaluated this EU–Norway management plan and concluded that the target FHCR = 0.3 with TAC constraint ±15% leads on average to a <5% risk of B < Blim within the next 20 years. Increasing the target FHCR increases the risk. Although the management plan has not been fully tested (e.g. at lower fishing mortalities), ICES concludes that the management plan can provisionally be accepted as precautionary and be used as the basis for advice. Interannual quota flexibility has also been evaluated and it is concluded that this has no significant impact on sustainability.

ICES advises that the exploitation of North Sea and IIIa haddock be based on the agreed management plan. This would imply landings of 38,000 tonnes in 2010, which would lead to an SSB of 185,000 tonnes in 2011. The ±15% constraint on interannual TAC variability has been invoked in this case, decreasing the proposed 2010 landings compared to the 2009 quota.

Discards of haddock in 2006 and 2007 were fairly substantial due to the moderately sized 2005 year class entering the fishery, but were considerably lower in 2008, possibly due to the growth of the 2005 year class past the minimum landing size. Further improvements to gear selectivity would reduce the amount discarded by allowing the release of undersized fish. This would not only be beneficial for haddock stocks, but also juveniles of other species that occur in mixed fisheries where haddock are caught.
Due to the 2006 – 2008 year classes being weak, even at the current low level of fishing mortality the spawning stock biomass is likely to continue to decline from 2010 onwards unless a moderate to strong year class appears. Early indications from surveys suggest that the 2009 year-class will be rather better, although it is too early to determine the extent to which this will contribute to the fishable stock.

ICES have recommended the development of a management plan, which would offer maximum protection to the [west of Scotland] haddock, while recognizing that it is caught in a mixed fishery. Special attention needs to be given to the sporadic nature of the haddock recruitment and how to manage periods of low recruitment interspersed with large, occasional pulses. In recent years around 50% of the total catch in weight has been discarded, so restricting landings alone may not achieve the necessary increase in SSB. Mainly 1- to 4-year-old haddock are discarded.

With recent recruitments since 2004 being relatively poor, ICES advised a complete closure of the haddock fishery in 2010. Doing so would bring SSB very close to Bpa in 2011.
Last year's assessment indicated that SSB would continue to decline as the 1999 year class moves out of the population and recent recruitment continues to be poor; the current assessment is consistent with this.

At present there are no management objectives in place for the Rockall stock. Yet there is a need for an internationally agreed plan. Such a plan should involve extensive collaboration between stakeholders, scientists, and management authorities in both the design and the monitoring of conservation measures.

Fishing mortality around F0.1 (0.18) can be considered as a candidate target reference point consistent with taking high long-term yields and achieving a low risk of depleting the productive potential (< 5%). The present fishing mortality (0.23) is above the candidate reference point, but below Fpa.
Even though SSB is expected to remain above Bpa in the short term, the recruitment for the last three years has been low. Providing advice on the basis of precautionary reference points and increasing fishing mortality to Fpa in 2010 would result in a 28% reduction in SSB by 2011.

ICES advises that there is little gain on the long term yield by increasing fishing mortality above current levels. For 2010, ICES recommends limiting catches to 4,280 tonnes, of which 3,330 tonnes are landings.
The TAC only applies to catches in the EU zone. It should apply to all areas and countries having fisheries for this stock. Since 1999 part of Division VIb has been in international waters where non-EU vessels are not subject to TAC. This allows for an unregulated fishery in the Rockall area. In addition, misreporting and discarding can lead to removals that exceed the TAC.
In comparison with previous assessment and advice, the overall trends are similar to those obtained last year. Estimates of fishing mortality have been revised upwards by 7%, and SSB has been revised downwards by 9% for the last year.
The basis for the advice is the same as last year.

These figures are provisional	EU TAC	UK Share
North Sea	26,965	22,698
West Coast	2,673	2,053

La Scozia ha condotto una valutazione della norma sul raccolto alla base dell'accordo di gestione per il Mare del Nord. Il successo nel mantenimento di una mortalità alieutica relativamente modesta, in linea con il programma, ha permesso alla generazione di eglefini del 1999, particolarmente nutrita, di contribuire nel corso degli anni alle attività di pesca, colmando il vuoto fino all'ondata di abbondanza successiva, nel 2005. Nell'ambito di un continuo sforzo teso a sviluppare metodi scientifici, un progetto di collaborazione tra il settore e la ricerca scozzese metterà a confronto il rendimento delle reti sperimentali con quello delle attrezzature commerciali. Ulteriori progetti relativi all’equipaggiamento per la pesca affronteranno in futuro il problema delle catture accidentali durante la pesca all'eglefino.