Jim Treasurer reports
Unravelling the wrasse fisheries statistics
THE wrasse fisheries in Norway, England and Scotland have provided good quality live fish for sea lice control and, together with mechanical methods, have contributed to a large reduction in medicine use.
They have also been an opportunity and economic boost for inshore fishermen. However, some NGOs were critical of the fishery.
A report from the Marine Conservation Society (MCS) to last year’s ECCLR (Environment, Climate Change and Land Reform) committee (January 2018, http://www.parliament.scot/ S5_Environment/Inquiries/009_Marine_Conservation_Society.pdf) mentioned the size of the wrasse fishery to supply cleaner fish. It talked about a ‘decimation of local populations of wild caught fish’.
Much of the information from this submission was from the MCS report on cleaner fish of 2013 (IFFO RS/MSC Standards Comparison Project paper).
I think that the 2013 report did not give the committee the most up to date information on the cleaner fish fisheries, nor the current knowledge on cleaner fish welfare requirements.
Wrasse remain one of the most abundant inshore fishes on the south and west coasts of the UK and Ireland.
They are captured with passive fishing gear, such as traps and fyke nets that are both environmentally friendly and non-damaging to wrasse, ensuring they are in good condition and that fish outwith size retention limits can be returned to the sea intact.
The MCS submission to the Scottish parliamentary inquiry quoted that the wrasse fishery in the UK was divided in volume as two thirds from English fisheries and one third from Scottish waters.
Trying to get updated figures for the size of the wrasse fishery in Scotland has not been easy. Also, accurate wrasse fishery data were not available for Scotland prior to 2014.
I attempted to track down the fishery statistics for 2017, which are always reported about one year in arrears.
In contrast, fishery data for wrasse from Norway are normally known within a month or two of the year end. Some 26.6 million wrasse were captured in Norway in 2017. The fishery quota for Norway in 2018 was assigned as 21 million fish.
I checked the official fisheries statistics for both Scotland and England and Wales. Initially, a freedom of information request for statistics on the wrasse fishery in 2017 to Marine Scotland was rejected as the statistics were not collated.
However, the Scottish Sea Fisheries Statistics 2017 were published in September 2018 (www.gov.scot/publications/scottish-Sea-fisheries-statistics-2017). It was surprising that wrasse were not listed in the report, unlike previous years.
But, following a direct request to both Marine Scotland and the Marine Management Organisation (MMO), that regulates fisheries in England, for equivalent figures for England and Wales (mostly the English Channel), they supplied me with the wrasse catch returns for 2017.
A drawback with the ‘official’ published figures is that fisheries reporting data are supplied in live weight only (tonnes) and not as numbers of wrasse. This is less helpful in management of these small inshore fish, where numbers are more meaningful.
The weight nominally estimated for wrasse by Marine Scotland Fisheries Inspectorate is 60g. I don’t know if readers would agree with that average weight. Ballan is a larger wrasse species but the size for stocking should not exceed 24cm, which does ensure that larger ballan that are potential broodstock are being returned to the sea.
Many of the wrasse captured until recently were the smaller species, goldsinny and rock cook, which can dominate wrasse catches in many areas of west Scotland, and can comprise from 70 to 83 per cent of catches.
These wrasse species are small and much of the wrasse catch may be less than 60g, so 50g may be a better average estimate of weight for all wrasse species.
The figures 50-60g have therefore been used to give a range in the estimates of wrasse catch. In recent times, the minimum size of wrasse retained in Scotland has been increased from 11 to 12cm, so smaller wrasse species may comprise a minor proportion of the retained catch in 2018 and 2019.
The total reported live weight of wrasse captured and retained in 2017 was 39.5 tonnes in Scotland which approximates to 658,000-790,000 wrasse.
The figure quoted by the MMO for England and Wales is 14 tonnes, equivalent to 233,000280,000 and much less than the over one million fish annually quoted in a CEFAS report (Ellis et al., 2017).
The larger share of the catch is therefore coming from local waters in Scotland. Also, some of the wrasse caught in England may be supplied as food fishes (see the Cornwall Good Seafood Guide) or for use as creel baits.
For example, wrasse catches in England and Wales were reported by the MMO as 22 tonnes in 2000, 25 tonnes in 2001, and 21 tonnes in 2002, but I cannot recall large numbers of wrasse being stocked in these years in salmon farms!
The technique had taken a dip, due in part to the introduction of new sea lice medicines. Only very small numbers of wrasse, and locally caught, were being stocked in Scotland in the early 2000s and this was mainly in the Western Isles.
This would suggest that many, if not all, of the wrasse being captured in England at that
“They remain one of the most abundant inshore fishes on the south and west Ireland” coasts of the UK and
time were not destined for salmon farms, and this may still be the case. The wrasse fishery in Scotland is managed and there is compliance of wrasse fish with fishery management measures by industry, following consultation with Marine Scotland, and also in welfare compliance with RSPCA Freedom Foods standards (2018). This has been aided by support and guidance on good practice by the SSPO (Scottish Salmon Producers Organisation).
The length size limits for the catch are 12-17cm for smaller wrasse species- that is, goldsinny, rock cook and corkwing. This means that the bulk of the smaller wrasse catch is no longer retained.
For larger wrasse species, namely cuckoo and ballan, the catch limits are 12 to 24cm. The size limits in Norway are slightly different, as illustrated here (see graph, right).
The lower size limit ensures that the smaller wrasse species have the opportunity to spawn over several years before being retained by the fishery.
The maximum retention length of 24cm for ballan wrasse ensures that larger fish that are potential broodstock are returned to the sea.
A closed season for fishing in Scotland from December 1 to May 1 was agreed voluntarily. Similar size retention limits are set for wrasse in the English Channel fishery.
The ultimate goal is to farm all wrasse that are required by salmon farmers, and efforts are being made to improve on current ballan wrasse survival in the hatchery and to increase production figures.
However, many in the industry, and especially in Norway, currently require access to wild caught wrasse to supply sufficient cleaner fish for stocking.
In the meantime, the collection and submission of accurate catch data for wrasse fisheries, and also the proportion of the catch returned to the sea, will help management of the stock.
Catch data and purchases by fish farming companies are therefore being made available to Marine Scotland and further study will assist in good management practice.
What may be of equal importance to the
volume of the wild wrasse catch are welfare issues, and fishermen and salmon farming companies have to comply with the RSPCA assured standards (2018), which stipulate that wrasse are captured and handled with the highest regard for welfare.
These standards include ensuring that the bycatch of other fish species, crabs and smaller wrasse is carefully handled and returned to the sea.
The recommended environmental conditions, especially fish densities, water temperature and oxygen, should be strictly adhered to during fish capture, storage and transport.
The stocking of wrasse should follow best practice, with the provision of supplementary feed and adequate numbers of hides, and perhaps also stocking fish into small nursery pens within the main pens to acclimate wrasse before release.
More information on both the wrasse and lumpfish fisheries in Europe is given in a fisheries chapter (Kousoulaki et al., 2018) in the publication Cleaner Fish Biology and Aquaculture Applications (5m). This summarises data from lumpfish and wrasse fisheries, gives the current fishery regulations, and reports catches in Ireland, Scotland, England and Norway. It also gives suggestions for improved fishery management practice.
“The larger share of the catch is Scotland” coming from local waters in