Data from the respected scientific body, the International Council for the Exploration of the Sea, reveals a significant fall in fishing pressure on stocks in the north-east Atlantic. At the same time, the analysis of ICES data over a period of time shows that the main fish stocks of interest to Scottish fishermen are increasing in size.
The latest ICES underlines the very clear trend in falling fishing pressure over the last decade. In particular, the data shows that the decline in fishing mortality is not just confined to one species group, but is spread across all the main fisheries – demersal (such as cod and haddock), benthic (such as place and sole) and pelagic (such as mackerel and herring).
The fall in fishing pressure is the result of a variety of factors including measures to protect cod, the introduction of long-term management plans for fisheries, and fishermen (such as in Scotland) adopting innovative conservation measures such as technical alterations to nets and real-time area closures to protect spawning and juvenile fish.
The full ICES report can be viewed at http://www.ices.dk/sites/pub/Publication Reports/ICES Advice/2011/ICES ADVICE 2011 BOOK 1.pdf
Furthermore, a recent report from the NAFC Marine Centre in Shetland, which has collated and summarised information published by ICES, shows that despite past declines, the abundance of most whitefish stocks of interest to Scottish fishermen has increased in recent years, in some cases by substantial amounts. At the same time fishing mortality rates – the proportion of fish that are caught each year – have fallen sharply.
The report reveals that while some whitefish stocks declined in size prior to the mid-2000s, the spawning stock biomasses (SSB) of almost all of them have increased since then. In almost all cases the SSB in the most recent year (2012) was between 50% and at least 100% higher than the average over the years 2005 to 2007. The one main exception was haddock, for which the upturn started later. However, the SSB of haddock in 2012 was at least 40% higher than the average over the years 2009 to 2011 in both the North Sea and West of Scotland areas. For north-east Atlantic mackerel, which is currently the focus of a major international quota dispute with Iceland and the Faroes, the SSB in 2012 remained well above the long term average (20% above the average SSB in the 1980s and 1990s).
The other clear trend from the report – Trends in Scottish Fish Stocks – is the confirmation that fishing mortality rates for all the species covered have declined over the last decade in the North Sea and/or West of Scotland areas, in most cases by at least 20%, and in some cases by much more.
Some of the report’s key findings include:
- The SSB of North Sea haddock in 2012 is 4.5 times larger than 1991.
- The North Sea cod stock more than doubled in size between 2006 and 2012.
- The fishing mortality rate for North Sea cod was lower than in any year since 1966.
- The plaice stock in the North Sea was larger in 2012 than at any time since 1960.
- The combined SSB of North Sea cod, haddock, whiting and plaice in 2012 was 40% larger than in the 1990s.
- The combined SSB of West of Scotland cod, haddock, whiting and plaice generally declined to 2010, although the rate of decline became much less after 2006. There was a marked increase in the SSB after 2010, with a 72% increase to 2012.
- The average fishing mortality rate on the West of Scotland was less than half that in 2000.
Meanwhile, the report also reveals that the aggregate SSB for the North Sea, and for North Sea and West of Scotland combined, have remained relatively constant, albeit with some fluctuations over the last two decades. This suggests that fluctuations in abundance of the different species – to some extent at least – cancel each other out. Further evidence for this comes from the fact that in the North Sea, the variability of the total SSB was less than the variability of individual species. This would indicate that a long-term ‘ecosystem approach’ to fisheries management would offer the most sensible option for the future, rather than inappropriate knee-jerk responses to short-term fluctuations in the stock levels of individual species.
The full report can be downloaded from http://www.nafc.ac.uk/Fisheries-Policy-Notes.aspx
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