Offshore Marine Protected Areas (MPAs): proposed fisheries management measures advice notes

Following a public consultation on fisheries management measures in Scotland’s offshore Marine Protected Areas (MPAs), further scientific advice was sought to support the revision of measures for two specific sites. This advice provides updated evidence to help ensure that management is effective. 

Management approach for the designated features burrowed mud and offshore deep-sea mud

Sites under consideration: Central Fladen (CFL) and East of Gannet and Montrose Fields (EGM) MPAs.  

For East of Gannet and Montrose Fields MPA the measures provided a feature coverage of 60%, 70%, 80% and 90%, corresponding to Option A, B, D and D respectively.  

For Central Fladen MPA, the measures provided a feature coverage of 56%, 62%, 67% and 70%, corresponding to Option A, B, C and D respectively.  

Revised measures for CFL and EGM were developed in line with JNCC advice and were reviewed by the Chef Scientific Advisor Marine who provided the following advice.  

The reference documents are: High level site summary 

Summary conclusions 

The conclusion of JNCC that the original proposed measures for both EGM and CFL are insufficient to result in MPA recovery seems well justified. This conclusion is based on new evidence post-consultation, and the correction of an error in the original analysis. 

All new options propose restricting more that 50% by area of the protected feature. 

The question of whether 50% mobile gear usage within a protected feature constitutes recovery at the MPA level requires management judgment rather than scientific assessment. Given inherent uncertainties, a precautionary approach would suggest that restricting mobile gear access to two-thirds of the protected feature provides sufficient basis for determining that the feature is recovering across the entire MPA. 

For CFL: Option C gives a headline figure that two-thirds (67% by area) of the burrowed mud would have protection from mobile demersal gear.  

For EGM: Option B gives a headline figure that a little over two-thirds (70% by area) of the burrowed mud in EGM MPA would have protection from mobile demersal gear.  

The predicted system response to adopted measures carries uncertainty; for both CFL and EGM Option A carries more risk than Option B, and Option B more than Option C. It is not currently possible to categorise the risk more clearly; in this I agree with JNCC. 

Given the uncertainties, and the present lack of evidence required to give evidence-based advice on a relationship between the level of zoned measure and the level of risk of not achieving conservation objectives, more monitoring is required to determine whether the chosen measure is effective, and a time-limited, adaptive review mechanism should be built in. 

Annex: detailed considerations 

The issue concentrates around interpretation of the phrase “significant risk of not achieving conservation objectives.”  The conservation objectives are “recover to a favourable condition.” The word “significant” used in this context does not have a scientific definition, it is therefore open to subjective interpretation, and expert judgement must be used without quantifiable scientific metrics. 

High confidence conclusions from the assessment/analysis indicates: 1) for East of Gannet and Montrose, the higher the percentage closure the lower the risk; and 2) for Central Fladen this is true up to a point, and beyond that point, increasing percentage closure introduces new risks associated with activity displacement (a response impact, rather than a direct impact). The precise percentage closure at which this change to adverse consequences occurs in unknown. 

Recovery to favourable conditions requires zoned closure. The critical question concerns the extent to which closure is required. The degree of recovery relates to reduction in fishing effort, which relates in approximately linear proportion to the percentage of closure in terms of area of protected feature (mud). That is, since mobile gear disturbance is primarily local to the activity it is fair to conclude that percentage of closure approximately equates to percentage of recovery. Unclosed areas will not recovery to favourable conditions; closed areas will.  

If half of a feature is restricted, would one consider the feature as a whole to be in recovery? This is a subjective judgement. Given inherent uncertainties in ecological systems my judgement would be that a higher level of restriction is desired. Specifying the exact level is impossible, given the current level of scientific evidence and understanding 

Central Fladen MPA 

JNCC’s post-consultation feedback maintains that under the original measures† (zoned closure to demersal mobile gear), there would “remain a significant” risk to burrowed mud with “a continued risk of not achieving the conservation objectives.” These statements from JNCC imply that the original measures† maintains the status quo of “a continued risk of not achieving the conservation objectives.” 

Following this post-consultation feedback, four new zone options were developed (Option A, B, C and D). These correspond to 56%, 62%, 67% and 71% by area of the burrowed mud (the protected feature) within the MPA, respectively and are in approximate proportion to fishing effort, based on historical records.  

Based on current science evidence it not possible to conclude with certainty which of these four options, if any, will achieve the conservation objectives. 

However, the likelihood of achieving the conservation objectives within the MPA increases as the percentage of fishing effort over the feature decreases. 

There are, though, confounding influences of fishing effort displacement from protected zones. 

External consultant ABPmer conducted a Strategic Environmental Assessment on the original measures, which concluded the full closure would have a minor adverse impact overall (from other gear types) compared to the consultation zoned closure (The original measures, approximately 40% by area of the burrowed mud within CFL MPA) which would have negligible adverse impact. Similarly, the original measures zoned closure of ~40% has a predicted moderate beneficial overall environmental impact compared to only a minor beneficial impact for full closure. 

JNCC are unable to say at which level (percentage) of closure the balance tips towards these two adverse consequences identified for full closure. 

Any recommendation on what level of closure significantly reduces the risk of not achieving conservation objectives and at the same time avoids adverse impacts of full closure cannot therefore be based on scientific evidence currently available. 

Option B gives a figure that less than two-thirds (62% by area) of the burrowed mud in CFL MPA would have protection from mobile demersal gear. This is 22% greater protection by area than the original measures. Option C raises the headline proportion of protection to two-thirds by area (67%) of the mud within the MPA. 

Option D could well be to be moving towards losing the moderate beneficial overall environmental impact of lower percentage closures. 

East Gannet and Montrose Fields MPA (EGM) 

JNCC now considers that the zoned closure presented in the consultation presents a significant risk to not achieving conservation objectives, due to an error in the original analysis. 

Consideration of EGM MPA differs from CFL. The SEIA identified no increased adverse overall environmental impact of full closure. 

In that sense there is no optimal level of zoned closure.  

Further, there is no direct evidence to quantitatively relate the degree of closure to increasing likelihood of meeting the sites’ conservation objectives.  

Four new zoned measures were developed (Option A, at 60%, Option B 70%, Option C 80%, and Option D 90%). The numbers represent the percentage by area of the protected feature (mud) covered by demersal mobile gear restrictions (excluding seines).  

The original measures†† protected 29% by area of the protected feature in the EGM MPA). 

All Options A, B, C and D increase the protected zone to more than half of the protected feature by area (60%, 70% and 80% and 90%) respectively. 

Option B is the closest to two-thirds zoned closure of the protected feature. 

Further information

Following the advice, the Chief Scientific Adviser Marine provided additional comment: 

"I confirm that Option B for both sites is consistent with my advice.  To elaborate: I am content that option B for either site would avoid significant risk of the remaining fishing activity hindering the conservation objectives, which is not the case for option A.  

"Options B lie between 60% and 70% of the protected feature being restricted which I would regard as approximately two-thirds, which itself is an indicative figure and not an absolute target. "