Nephrops fleet - optimisation modelling: policy brief

Economic research providing a valuable addition to the evidence base of Scotland’s Nephrops fishery to help inform discussions on the future of fisheries management.

Understanding the Report

To deliver on the objectives of this research consultants Sandfish Associates developed and applied a novel way to assess whether the current allocation of access to Nephrops fishing grounds is optimal. This used more spatial data on fishing activity for over 12 metre vessels and new data on the spatial distribution of under 10 metre vessels, to provide a more detailed picture of the location of fishing activity of the Nephrops fishing fleet than has previously been available. For modelling purposes, the Scottish Nephrops fleet was split into 25 fleet segments, covering 85% of Scottish Nephrops landings, according to their characteristics (length, area fished, etc.). 

The optimal allocation of access to fishing grounds was examined under two broad scenarios:

1. Scenario 1 - maximising gross value added for the 2017 Nephrops fleet. This is a measure of the contribution of an economic activity to the economy and broadly captures income to workers and company profits; or,

2. Scenario 2 - maximising full time equivalent employment for the 2017 Nephrops fleet. This is a standardised measure of employment that takes into account different working patterns.

The model optimises for the above scenarios following three broad steps: 

i. estimating each Nephrops vessels’ fishing and economic characteristics based on 2017 data;

ii. determining the best way to fish in each of the 355 spatial areas modelled across Scotland’s inshore waters based on 2017 fishing patterns;

iii. determining the best area for each vessel to fish for Nephrops based on its characteristics from (i). 

The fishing activity for each of the scenarios was compared with current activity based on 2017 to highlight where there is opportunity to either increase employment or gross value added primarily using an economic model that does not explicitly take account of biological stock dynamics between gears. The optimisation process incorporates a number of constraints that are designed to increase the realism and applicability of the model. It shows where fishers may be best off locating their fishing activity to maximise fleet’s gross value added or employment. Further detail is presented in the accompanying main research report.

However, the research was not commissioned to nor does consider the costs and practicalities of achieving such an optimal setup. First and foremost, this economic research is not a policy appraisal, it provides valuable information of what an optimal setup of the Nephrops fishery could have looked like in 2017 from a spatial perspective under the two modelled scenarios. The impacts of such a setup in relation to wider economic considerations as well as social and environmental considerations was not within the scope of this work. Any policy or arrangement aimed to move the Nephrops fishery closer to such optimal positions would likely have compliance and operational costs and considerations. Crucially, the economic research does not explicitly explore what the drivers are of the current setup. 

These and other points would need to be carefully considered as part of the Future of Fisheries Management discussion.



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