Fish Stocking – A Case for Benchmarking

The performance of England’s Environment Agency in respect of fish stocking is hard to judge.  The numbers it has published don’t help very much. 

 A recent press release by England’s Environment Agency reports that in 2015 it released record numbers of coarse fish into rivers and lakes following pollution incidents or where fish stocks were low (1).  Those who like precision can read that the fish released included 53,729 chub, 46,850 dace, and so on, a total of 452,220 over nine species, plus 1.3 million larvae.  The fish were bred at the Agency’s fish breeding farm in Nottingham, and releases took place at sites across England.  This information was widely but uncritically reported in the media (2).

This is focusing on the easily measurable rather than the important.  These figures are of some use as a performance indicator for the fish breeding farm, though even in that context they need to be considered in conjunction with indicators of its unit costs and of the quality of its fish.  What they don’t indicate – and to be fair the Agency doesn’t claim that they do – is the overall performance of its fish restocking efforts, let alone of its effectiveness in fulfilling its duties in respect of fisheries and the aquatic environment.

Let’s consider what might be suitable indicators of the Agency’s fish restocking performance.  For an individual site where restocking has taken place, we are interested in whether the restocking is effective in re-establishing a self-sustaining fish population.  A possible indicator is:

Ratio of (Fish population 1 year after restocking) to (Fish population immediately before restocking)

No doubt this and the other indicators below could be refined in various ways.  Allowance might be made for: species mix; time for larvae to grow to adulthood; fish health; post-restocking incidents; and so on.  The aim here is just to identify the kinds of measures that would be useful indicators.  Where the restocking follows a pollution incident, a further indicator might be:

Ratio of (Fish population 1 year after restocking) to (Fish population before pollution incident)

For each of the above ratios, there might be assessed a threshold at which the restocking could be considered successful.  This would make possible indicators that could be calculated periodically on a regional or national basis:

Number of sites at which restocking was successful

Percentage of restocking attempts that were successful

Then there is the issue of unit costs, a possible indicator being:

(Total costs of the Environment Agency’s fish breeding and restocking operations) divided by (Number of sites at which restocking was successful)

Wherever possible, the Agency’s performance against such indicators should be benchmarked against that of other operators.  Since private fish stocking operations mainly supply fish for small private ponds, the best comparators may be public sector operators in other countries.  In the US, for example, public sector fish stocking is organised at state level, offering many potential comparators, although complications are that the species stocked differ from those in England, and more of the stocking is on a regular scheduled basis to replace fish caught and not released (3).  Benchmarking is not easy, but public bodies whose operations are largely free from the pressure of competition should attempt it, or commission benchmarking studies from specialists, to monitor their performance and identify where it falls short of best practice with a view to improvement.  They should also publish the results as part of their public accountability.

The Environment Agency’s fish restocking operation may be performing well.  I’m not aware of any evidence that it isn’t.  Equally, I haven’t found any evidence that it is. The only benchmarking study of any kind that I could find on the Agency’s websites relates to hydraulic flood models, and this appears to be an evaluation of available models which it might use, not a benchmarking of any part of its own performance (4).  Its Corporate Plan includes a ‘corporate scorecard’ listing various measures and targets, but at a fairly high level and none relating specifically to fish restocking (5).

There is a wider point here.  Environmental conservation is a serious business that isn’t helped by media reporting of simplistic numbers vaguely suggesting that something good is being done, whether they are numbers of fish restocked, numbers of trees planted, tons of material recycled, or numbers of homes powered by renewable energy facilities.  Consideration always has to be given to quality as well as quantity, consequences as well as actions, and costs – including the opportunity cost of not committing available resources to other conservation projects – as well as benefits.

Notes and References

  1. Environment Agency Press Release 11/2/2016 Almost 2 million fish released into England’s rivers
  2. The BBC’s report gave additional information not in the press release. See
  3. See for example Arizona Game and Fish Department Arizona Fish Stocking Schedules  (Accessed 24/2/2016).  The ‘daily bag limits’ indicate that much fish is caught and not released, whereas in England a high proportion of angling in inland waters is on a ‘catch and release’ basis.
  4. Environment Agency: Evidence Directorate (2013) Report SC120002 Benchmarking the latest generation of 2D hydraulic modelling packages
  5. Environment Agency Corporate Plan 2014-16  p 41
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