1. Identifying chokes Stuart Reeves
NSAC Choke Avoidance Measures Symposium,
Copenhagen, 2-3 November 2016
This work has its roots in a project funded by Fisheries Innovation Scotland (which is supported by the EMFF) but has expanded beyond that in the light of a request from Defra to review all UK stocks and identify potential chokes.
Project FIS012a
European Maritime and
Fisheries Fund (EMFF))

2. Why does choke occur? Catches Landing opportunities Vessel operation
Gear used
Fishing grounds
TAC setting
Quota allocation & trading
Choke arises from a mis-match between what vessels catch and what they have ‘landing opportunities’ for, in terms of quota. The catches are determined by the operational decisions made by the skipper at sea, i.e. where to fish and what gear to use. The landing opportunities are a result of the TAC-setting and quote allocation processes, i.e. from fisheries management in the broad sense. It is the latter aspects of choke that I consider here.
Vessel operation
Fishery management

3. Towards a risk-based approach to identifying choke
Detailed review of TAC-setting & quota allocation for major North Sea stocks
Identify key risks in the process.
Identify sources of information on these
Apply to full range of UK stocks to identify main choke risks
The overall approach is to take a risk-based approach to identifying choke stocks & fisheries. This will be based on a detailed review of the TAC-setting and quota allocation processes for some key North Sea demersal stocks in order to identify key risk factors and indicators of these. The latter will then be applied across all UK stocks to try and rank all stocks in terms of their choke risk. The work is ongoing and any results presented here should be regarded as preliminary.

4. TAC-setting A TAC Elements: Is a catch limit.
Is set based on the needs of the stock, not the fleet
Elements:
Catch and survey data
Stock assessment
Harvest rules & management objectives (MSY etc.)
Uplifts for Landing Obligation
Partitioning between areas
Note that a TAC is simply a total amount of fish that can be removed from a stock in a given year. It takes no account of how many vessels it will be spread across and there is no guarantee that it will last the whole year.
TACs are usually based on a catch forecast, which starts with a stock assessment. The stock assessment is based on catch and survey data for the stock concerned. The TAC will the be determined by the state of the stock relative to reference points such as F-MSY. As the Landing obligation is implemented, the TACs are alos now incorporating uplifts to account for fish that would previously have been discarded. In some cases, a stock covers multiple areas, so the forecast catch is partitioned across the different areas to provide individual TACs for each area.

5. TAC-setting risks Data-limited assessment/precautionary TAC
High/variable discarding
Reduction in fishing mortality required
Mismatch between stock distribution and area partitioning
A number of risk factors in TAC-setting can be identified:
If a TAC is precautionary or used for a data-limited stock, it is less likely to be able to track changes in abundance of the stock hence there is a greater risk of choke
If a stock has a record of high or variable discarding this may cause problems with the quality of the assessment and with any associated uplifts as the discard data tend to be of lower quality than the catch or survey data. This makes it another risk factor
Where a TAC is set to result in a reduction in fishing mortality compared to recent years this makes it a choke risk as the TAC is set lower relative to the abundance of the stock than was previously the case.
In cases where the stock distribution has changed since the area partitioning was established this is likely to increase choke risk in areas where the relative abundance has increased.

6. Quota allocation & trading
National allocations based on Relative Stability
Reference period:
Also Hague Preference (1975)
UK allocations based on FQA system
Reference period typically
Quota trading allows some flexibility to correct for this inertia
The existing quota allocation system has a lot of history as it was based on the status of stocks and fisheries (and also political priorities) 40 years ago.
In the UK the quotas are distributed according to catch history from the mid 1990s.
To get around all of this inertia a system of quota trading within the UK, and between the UK and other EU Member States has developed.

7. Quota allocation risks
Low national allocation
Recent changes in stock
Recent changes in fishery
High dependence on trading-in quota
Risk factors in the quota allocation process include a low national allocation of a given stock,. This is often the result of changes in stocks and/or fisheries since the allocation key was established. Such issues result in a high dependence on trading-in quota of the relevant stock.

8. Agreed allocations of North Sea demersal stocks
Relative stability plus Norway shares for North Sea demersal stocks.

9. Initial and ‘adapted’ UK quotas
The ‘adapted’ quota is the initial UK allocation plus any subsequent traded quota.
The figures in this graph are the differences between ‘initial’ UK quotas (i.e. relative stability allocations at the start of the year) and ‘adapted’ quotas (i.e. at the end of the year after all trading etc. has taken place). Hake stands out as the adapted quota in each of the four years presented here is around 300% higher than the initial quota. In this case the adaptations are likely to involve transfers from adjacent areas (which are permitted under certain circumstances for hake) as well as trading

10. Initial and ‘adapted’ UK quotas
The ‘adapted’ quota is the initial UK allocation plus any subsequent traded quota.
Y-axis truncated at 100% to avoid distortion by Hake figures
This is a version of the previous graph truncated at 100% on the Y-axis so that other stocks can be seen as well as hake. Positive numbers, such as cod and saithe, indicate trading-in of quota from other member states; negative numbers, such as plaice and Nephrops, show stocks where the UK is trading-out quota to other MS. In general, the higher the average adaptation, the higher the choke risk.

11. Example risk scores 1 2 3 TAC-setting (EU) Allocation (UK)
Data-limited
MSY
Discarding
Partitioning
National share
Stock changes
Fishery changes
Hake in the North Sea 1 2 3
This is an initial attempt to score a few North Sea stocks in terms of their choke risk factors. These include risk factors associated with TAC-setting, which will apply across all North Sea states, and risk factors associated with quota allocations, which are UK specific. In this example, the scale goes from 1, as a low risk, to 3 as a high risk. The hake is subject to a full analytical assessment and is fished below MSY so these aspects are low risk. There is some discarding, particularly of over-quota fish, hence a moderate risk for this factor. All other factors are high risk as the North Sea as a very low proportion of the overall TAC (3.5%, which is very low based on historically reported catches); the UK has only a small share of the North Sea TAC (c. 18% when the track record of catches over the relative stability reference period indicated a UK share of around 25%), and there have been large changes in the stock and fishery since the RS shares were established.

12. Example risk scores 1 2 3 … TAC-setting (EU) Allocation (UK)
Data-limited
MSY
Discarding
Partitioning
National share
Stock changes
Fishery changes
Hake in the North Sea 1 2 3
North Sea Plaice
North Sea Nephrops
North Sea … …
Preliminary risk scores here also for plaice and Nephrops indicating that different issues affect different stocks.

13. ICES Mixed fishery advice – Choking in mixed-fisheries
If all stocks could be caught
independently:
If all vessels fish until they have
exhausted all of their quotas:
Over-quota catches leading to discards
If all vessels stop fishing when they have
exhausted one of their quotas:
Quotas under-utilised, leading to fishing opportunities being ‘choked-off’
Catch (tonnes)
The ICES mixed-fishery model is another tool which could be helpful in identifying choke issues. The results presented here are at the stock level, but more detailed results cold be used to look at choke at fleet or national level.
The ICES mixed-fishery model (Fcube) takes the results of the annual ICES single stock advice (which assumes that all stocks are fished independently of each other) and adds information about the fleets that fish for those stocks. This recognises that the amount caught from each stock will not necessarily be constrained by the TAC, but will depend on how fleets fish in response to their quota shares. This is illustrated by two of the scenarios used to model possible future effort over the forecast years. These are known as the ‘Max’ Scenario, where all vessels continue fishing until they have exhausted all of their quotas, and the ‘Min’ scenario, where all vessels stop fishing as soon as they have exhausted their first quota. These are in effect extreme values which bracket the likely true consequences of the TACs, but it is also interesting to note that the introduction of the landing obligation could imply a shift away from the Max scenario and towards the Min scenario as it will no longer be legal to discard over-quota catches.
Scientific advice (North Sea, 2016)