21st June

Scientists skating on thin ice?

Dr Martin O'Farrell

The report of the Standing Scientific Committee of the National Salmon Commission: ‘The Status of Irish Salmon Stocks in 2006 and Precautionary Catch Advice for 2007’ is now the blueprint for the management of Irish salmon rivers. This report underpins government policy in relation to the management of wild Atlantic salmon in Ireland. 

With the operation of fisheries restricted to estuaries and rivers from 2007, assessment now focuses primarily on estimating individual river returns from catch data, counter data if available and rod catch exploitation rates.Catch of the day on the River Erriff. Photo Jim Stafford, Erriff Fishery

Catch of the day on the river Erriff. Photo Jim Stafford, Erriff Fishery

These data are then related to the estimated salmon Conservation Limit (CL) / spawning target for each river. The CL estimate is based on several catchment parameters (wetted area, latitude) as well as the salmon characteristics in the catchment (sea age, fecundity, sex ratio).

All CLs estimated in the SSC report relate to one-sea-winter salmon (1SW); their relevance on rivers where multi-sea-winter (MSW) salmon constitute a significant proportion of the run e.g. Slaney, Laune, Caragh, is questionable.


Assessment
The SSC looked at 151 rivers in the Republic of Ireland.  Of these, 15 had counter data; 2 had trap data, 58 had an average rod catch of more that 10 salmon (based on log-book returns from anglers), and 74 had a rod catch of less than 10 salmon (also based on log-book returns from anglers).

The SSC recommended the closure of the 74 rivers that had a rod catch of less than 10 salmon per year, on the basis that these rivers supported small vulnerable salmon populations. As these rivers contributed a very small percentage of the national rod catch, their closure was not important in angling catch terms.

Of the remaining 77 rivers, 43 were identified as having an identifiable surplus over the CL while 34 were declared not to have, and were closed for 2007.

Scientific literature is replete with references to the dangers of using salmon rod catch data to estimate stock abundance without knowledge of angling effort and rod exploitation rate.  

Designation of rivers for closure or open for harvest in 2007 seems to be at best, inconsistent and at worst, political. Consider the case of the Ballysadare River, Co Sligo (open for harvest in 2007).

On the Ballysadare, virtually all salmon are taken by anglers in the Sea Pool – downstream of the fish counter location. The fish pass is operated intermittently and the upstream count shows that the rod exploitation rates during the years 2001-2005 were between 29.5% and 40.7%, significantly higher than the national average of 14%. Based on these rod catch / count data, the Ballysadare should have been closed.

The text of the SSC report states:‘The Ballysadare River salmon population has persistently failed to achieve its spawning target. However it is likely to benefit substantially from the forgone commercial catch in 2007.’

The Ballysadare River was open for angling in 2007 with a quota of 848 fish!

There are fish counters on 15 rivers and the recommendations for closure/harvest based on rod catch/count are often as contradictory as the Ballysadare analysis given above.

Lack of sufficient data
The SSC was given an impossible and unenviable task. In my view, the SSC should have advised the NSC that insufficient scientific data existed upon which to base its recommendations, and should have refused to give advice on rivers for which it had no scientific index on salmon stock status (electric fishing survey data/fish counter data/effort related rod catch data etc).

Instead, the SCC relied in the main on log-book returns from anglers which detailed salmon caught, killed and tagged. This assessment system rewards heavy angling pressure, and anglers who kill and tag salmon (the reward being that the river in question would be open for angling in 2007 and beyond). On rivers where a conservative approach was taken, closure was the reward.

I sympathise with anglers/owners on such rivers; however I have little sympathy for anglers who under-declared their catch and have found rivers closed as a result!

This philosophy replicates that of the ‘three wise men’s’ hardship fund for commercial salmon fishermen who ceased operations in 2007: the more salmon they caught in the years 2001-2005, the higher their financial award from the State.

For salmon anglers on Irish rivers the message is also very clear: the harder you fish/the more salmon you kill and tag, the higher the stock status assessment!

 Inshore Ireland sent the following question to the NSS and was advised of ‘no comment’.

Q. In the cases of the 15 rivers with counters, do you believe that you have taken a consistent approach to the determination of exceedence of or failure to achieve CLs, and do you accept that the use of rod catch data to determine the open/closed status of rivers in 2007 and beyond is seriously flawed?


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