Risk-Based Assessments of Fisheries in MPAs

Transcription

1 Risk-Based Assessments of Fisheries in MPAs Suzannah Walmsley, ABPmer Common Language Group, 22 March 2016

2 Overview Background to project Overview of methodology Summary conclusions for case study sites Further information 1

3 Background and Context Defra, MMO and IFCAs carrying out assessments of fishing in European Marine Sites (EMS) Developed and trialled approaches to improve evidence for assessments Gears and how they may impact habitats Spatial and temporal information on fishing activities New approaches to assessing exposure to fishing Natural disturbance modelling to inform assessment, consider fishing in the context of natural processes 2

4 Overview of approach 3 case studies Gear impact modelling penetration depth, sediment resuspension Interviews Under-15m fishing distribution and intensity, gear configurations Natural disturbance modelling Mobility of sediments Presence of mobile bedforms Proportion of time Number of days Background on fishing activity Vessels Gears Landings Literature on gear impacts Habitat data & sensitivity VMS analysis gear components Frequency of impact, polygons of impact 3

5 3 Case Study Sites Site and gear combinations: Shrimp beam trawling in The Wash and North Norfolk Coast SAC Flatfish beam trawling in North Norfolk Sandbanks and Saturn Reef SCI Beam Shoe Otter trawling in Margate and Long Sands SCI Tickler chains 4

6 Approach to Assessments Consider designated features and the pressures they might be subject to from fishing Consider sensitivity to those pressures Sensitivity is a measure of the likelihood of change when a pressure is applied to a feature, as a function of that feature s capacity to tolerate the change and its subsequent ability to recover. Tolerance Sensitivity Recoverability Vulnerability Exposure 5

7 Sensitivity Biotopes (habitats and characterising species) php?speciesid= allery.php?album=673&pic=508 kipedia/commons/9/99/bathyporeia_pilosa.jpg&imgrefurl= ons.wikimedia.org/wiki/file:bathyporeia_pilosa.jpg&h=945&w=1259&tb nid=j8j518qtlcc4rm:&docid=pxhgm1g9alwggm&ei=jgdovvgjg4 KMatbml5gE&tbm=isch&ved=0CCQQMygEMARqFQoTCPGItZaCnck CFQKGGgodVvMFQw &ved=0cacqjrxqfqotcnm0_ugcnckcfqf_ggodva0d4q&url=http%3a%2f%2fwww. marlin.ac.uk%2fspeciesfullreview.php%3fspeciesid%3d3329&bvm=bv ,d.d2s& psig=afqjcngadndt_8zgelsws689rwdnpayooa&ust=

8 Gear footprints Conventional beam trawl UK under-10m triple rig otter trawl 7

9 Gear impact modelling Depth of penetration of individual gear components Quantity of sediment mobilised by the gear Models tested - consistent with other experimental results from sea trials and numerical results from simulation Single rig Triple rig Sediment mobilised into the water column (red lines) (measured in terms of the equivalent sediment depth in mm) and penetration depth in sand in mm (grey lines) of under-10m single rig and triple rig trawls across their swept path (in metres) 8

10 VMS analysis illustrative area 9

11 Individual pings 10

12 Tracks between pings 11

13 Buffered tracks (gear components) 12

14 Impact polygons (gear components) 13

15 Comparison with pings at normal scale perception! 14

16 Frequency of impact 250m grid 25m grid 15

17 Interviews Information on: Fishing gears Fishing patterns Fishing areas (mapping) Quantification of gear footprint (swept area), attributed to specific habitats (for under-15m vessels) 16

18 Natural disturbance modelling Development of a model to quantify how often the seabed is disturbed by natural processes Mobility of sediments and presence of mobile bedforms Proportion of time, and number of days per year Consider fishing disturbance in the context of levels of natural disturbance Recognise that fishing results in other pressures and impacts (penetration, crushing 17

19 Natural disturbance modelling 18

20 Margate and Long Sands Biotopes characteristic of highly disturbed environment Feature: Sandbanks Mainly under-10m vessels Pressures: Physical damage and disturbance (surface, shallow, deep), Siltation Removal of non-target species 19

21 Margate and Long Sands No vulnerability for most biotopes Low vulnerability for four biotopes Moderate vulnerability for one biotope (F. fabula) 20

22 VMS in relation to London Array 21

23 Conservation Objective to maintain, high levels of natural disturbance in the site arguable whether low vulnerability constitutes an adverse effect on integrity (AEOI) Significance of effects depend on the baseline against which CO s are assessed. Potential in-combination effects with beam trawl VMS data heavily influenced by guardship duties for London Array not an accurate reflection of fishing activity Official assessment: Margate and Long Sands 22

24 The Wash and North Norfolk Coast Feature: Sandbanks, mudflats, large shallow inlets and bays ~30 vessels Majority under-15m, but over-15m have higher effort Beam length 3-9m Pressures: Physical damage (surface abrasion, shallow disturbance); and Biological disturbance through the selective extraction of species (target, non-target) 23

25 The Wash and North Norfolk Coast Most biotopes no vulnerability Low vulnerability for some biotopes: Removal of target and non-target species (brown shrimp is a generalist predator) Physical damage and disturbance (due to very small area of biotope giving high exposure) Moderate vulnerability: Surface abrasion for sublittoral biogenic reefs (addressed through closed areas) 24

26 The Wash and North Norfolk Coast Vessels considering use of SeeWing hydrodynamic wing Under-15m interview data scaled up to fleet level using information from processors improved estimates of swept area Uncertainty over habitat data needs to update and ground-truth to confirm the presence and condition of biotopes Uncertainty over AEOI for removal of brown shrimp, as characterising species would occur at higher abundance where fishing reduces predation Official assessment: EIFCA not yet released their assessment 25

27 North Norfolk Sandbanks and Saturn Reef Feature: Sandbanks, Reefs Majority are Dutch beam trawl vessels (82% of pings), all over-15m Dutch fleet using pulse trawl with hydrodynamic wing Pressures: Suspended sediment concentration; Abrasion Biological disturbance through the selective extraction of species Electromagnetic changes 26

28 North Norfolk Sandbanks and Saturn Reef All pathways are either not vulnerable, or low vulnerability Scenario 1 conventional beam trawls Shallow and deep disturbance on all habitats low vulnerability except deep circalittoral sand (moderate) Biological disturbance through removal of target and nontarget species for all habitats - low 27

29 North Norfolk Sandbanks and Saturn Reef Scenario 2 Non-UK vessels are pulse trawls Shallow and deep disturbance on all habitats low Lower vulnerability than scenario 1, due to lower benthic impacts, and lower levels of bycatch Sabellaria reef is red risk Uncertainty over impact of electromagnetic changes 28

30 North Norfolk Sandbanks and Saturn Reef Conservation Objective to restore But not clear what is causing them to be in unfavourable status High levels of oil and gas activity High levels of natural disturbance in the site Assessment of AEOI uncertain low vulnerability uncertainty over electromagnetic changes Official assessment: Draft CFP management document for the site proposes 52% closure, based on generic high-level comments on trawl impacts 29

31 Conclusions Data and methods developed address a number of key data gaps for assessments of fisheries in MPAs (extent, intensity and frequency of impact, over- and under-15m) Improved evidence base, reduced uncertainty and need for precaution Assessments should be at level of gear component; methods provide an approach for implementing this Assessments should take account of levels of natural disturbance Engagement with industry improved information on fishing patterns, gear types and configurations, particularly for smaller vessels. Uncertainties in habitat extent and condition limit the reliability of conclusions, and should be addressed before restrictive management is implemented Guidance for determining significance of impacts should be developed, consider judgements on site integrity from other sectors 30

32 More information

33 Thank you for your attention Suzannah Walmsley