Salmon are a significant resource in the South West with an annual gross expenditure of more than £6 million.
ICES and NASCO require countries with natural stocks of Atlantic salmon to set criteria against which to give advice on stock status and to manage and conserve individual river stocks. In England and Wales, conservation limits (CLs) have been developed to indicate the minimum spawning stock levels below which stocks should not be allowed to fall. In the South West region there are 20 rivers selected as main salmon rivers representing 2299ha of accessible wetted area for salmon. These rivers range in size and characteristics throughout the region.
All 20 main salmon rivers in the South West have salmon action plans (SAP). These contain an agreed list of actions that the Environment Agency, in partnership with outside interests who support the plan, are committed to address in order to meet locally the objectives of its sea trout and salmon strategy “better sea trout and salmon fisheries” launched in 2008.
7 of these rivers are also designated as special area of conservation (SAC) under the EU Habitats Directive (92/43/EEC) on Conservation of Natural Habitat and of Wild Fauna and Flora with salmon being the “qualifying species”. This stipulates that member states maintain or restore habitats and species to favourable conservation status and maintain additional protection measures.
Salmon populations have declined in most rivers in the region, however this varies in each river catchment and with the weather patterns each year. In 2007, 85% of the main salmon rivers in the South West were at risk, or probably at risk of failing their management objectives. 10 rivers failed the 2007 CL compliance, 7 were recorded as 'uncertain' (6 of these achieved over 100% in 2007 but in previous years they have recorded below 100% causing the compliance to be 'uncertain'). 3 rivers passed the 2007 CL compliance these were the Camel, Fowey and Avon-Devon).
There is a similar pattern nationally, however improvements in some historically polluted rivers such as the Tyne, Wear and Ogmore have seen salmon returning.
There is concern about environmental degradation in rivers, mainly in rural areas, caused by changing land use practices, especially agriculture and forestry. Issues of particular concern are siltation resulting from soil and bank erosion, pesticides from sheep dip chemicals, acidification and changes in river flows. The relative importance of these effects vary around the country and in each river catchment. The extent and nature of soil erosion impacts are being investigated and national water abstraction licence legislation is under review.
Changes in the British climate are predicted to become more pronounced and the most likely scenarios are for higher temperatures, wetter winters, drier summers and more extreme events of flooding and drought. In the future we are likely to need to introduce measures to reduce river temperatures as much as possible, especially on the chalkstreams but also on the rain-fed rivers of Devon & Cornwall. Changes in climate are global and the increased natural mortality of salmon at sea in recent years may also be linked to climate change.
Conservation limits and management targets form only one part of the assessment of the status of a stock. Management decisions are never based simply on a compliance result alone. Because stocks are naturally variable, the fact that a stock is currently exceeding its CL does not mean that there will be no need for any management action. Similarly, the fact that a stock may fall below its CL for a small proportion of the time may not mean there is a problem. Thus, a range of other factors are taken into account. These include the structure of the stock and any evidence concerning the status of particular stock components, such as tributary populations or age groups. It is based on patterns of run-timing and the production of juveniles in the river sub-catchments.
Hampshire Avon and Dorset rivers
The Frome has been consistently around or above its CL for a number of years but its compliance is 'uncertain' as in 2003 & 2005 it recorded slightly below 100%. In 2012 its compliance is also predicted to be 'uncertain'. The Hampshire Avon, Stour and Piddle all failed their CLs compliance and all of them are predicted to 'fail' in 2012.
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Proportion of conservation limit attained from 1998 to 2007 in Hampshire Avon and Dorset salmon rivers
East Devon rivers
The River Exe has been above 100% since 1998 but its compliance is listed as uncertain because it is categorised 'probably not at risk' in the management objective.* The Teign has recorded above 100% in 2006 & 2007 however its compliance is 'uncertain' as it recorded below this limit previously. Both the Exe and Teign are predicted to be 'uncertain' compliance in 2012. The Axe failed it compliance in 2007 and is predicted to 'fail' in 2012.
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Proportion of conservation limit attained from 1998 to 2007 in East Devon salmon rivers
South Devon rivers
The River Avon in Devon passed its compliance and its predicted to do so in 2012. The Dart, Erme and Yealm have all recorded above 100% in the past but have all failed in 2007. In 2012 the Dart is predicted to have 'uncertain' compliance while the Yealm and Erme are both listed as 'fail'.
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Proportion of conservation limit attained from 1998 to 2007 in South Devon salmon rivers
Tamar, Lynher, Tavy and Plym rivers
The Tamar has the highest CL limit set in the South West. In 2007 it recorded below 100% but its compliance is 'uncertain' as it passed all previous years with exception of 2004. The Lynher compliance was also 'uncertain' despite passing 100% in the past 4 years. The Plym and Tavy both failed the 2007 compliance. The Tamar, Tavy and Lynher all are predicted to have 'uncertain' compliance in 2012, while the Plym is predicted to 'fail'.
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Proportion of conservation limit attained from 1998 to 2007 in the Tamar, Lynher, Tavy and Plym salmon rivers
Fowey and Camel rivers
The Fowey and the Camel both 'pass' the 2007 compliance and both consistently record over 100% since the scheme started. Predicted compliance in 2012 is also a 'pass' for both rivers.
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Proportion of conservation limit attained from 1998 to 2007 in the Fowey and Camel salmon rivers
North Devon rivers
The Taw has only recorded below the 100% CL twice since 1998, in 2001 and 2005 respectively which has caused its compliance to be listed as 'uncertain'. The Lyn has consistently recorded above its compliance however it is also listed as 'uncertain' * .The Torridge failed its compliance in 2007 only attaining half of its conservation limit.
* listed as 'uncertain' because it is categorised as ‘probably at risk’ and 'probably not at risk' in the management objective. This due to the level of variability in the egg deposition estimates and the way in which the compliance procedure works. For further explanation please refer to Annex 2 in the Annual Assessment of Salmon Stocks and Fisheries in England and Wales 2007.
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Proportion of conservation limit attained from 1998 to 2007 in North Devon salmon rivers
Compliance with management objectives
Compliance is based on the probability of the river meeting the management objective. It can be basically explained that the stock should be meeting or exceeding its CL in at least four years out of five. Status of the main salmon river catchments against their management objectives in 2007.
In the South West compliance with the management objective in 2007 was:
- 3 rivers (15%) were classified as ‘not at risk’ – i.e. had a high probability (> 95%) of meeting the management objective
- 2 rivers (10%) were classified as ‘probably not at risk’ – i.e. had a probability of between 50% and 95% of meeting the management objective
- 6 rivers (30%) were classified as ‘probably at risk’ – i.e. had a probability of between 5% and 50% of meeting the management objective
- 9 rivers (45%) were classified as ‘at risk’ – i.e. had a very low probability (<5%) of meeting the management objective.
In England and Wales compliance with the management objective in 2007 was:
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10 rivers (16%) were classified as ‘not at risk’ – i.e. had a high probability (> 95%) of meeting the management objective
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15 rivers (23%) were classified as ‘probably not at risk’ – i.e. had a probability of between 50% and 95% of meeting the management objective
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10 rivers (16%) were classified as ‘probably at risk’ – i.e. had a probability of between 5% and 50% of meeting the management objective
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29 rivers (45%) were classified as ‘at risk’ – i.e. had a very low probability (<5%) of meeting the management objective
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Status of the main salmon river catchments against their management objectives in 2007