Further advice on fishing activity relevant to Special Protection Areas (SPAS) in the MPA network

 

Please note - The advice below was produced (January 2024) to assist the development of proposed management measures for fishing activity for Marine Protected Areas (MPAs) and Priority Marine Features (PMFs) (11 most sensitive to bottom contact gear) outside MPAs. Further considerations were made by Marine Directorate and the final proposed management measures being consulted upon in 2026 are available via Scottish Government’s website.

January 2024

Background

NatureScot is in the process of publishing Conservation and Management Advice (CMA) on SiteLink, for marine and colony SPAs that form part of the MPA network. The CMAs provide site-specific advice for stakeholders on the conservation objectives of the protected areas and identify a range of pressures and activities that may affect the protected features of the site. This report outlines NatureScot’s generic advice on fishing activities used to inform the CMA and presents potential options for further site-specific refinement based on interpretation of dive-depth and prey-supporting habitat analysis of the protected features. 

This report provides detail of the relevant data used, methods and analysis by NatureScot. Section 2 provides an overview of the fisheries advice provided in the CMAs, sections 3 and 4 provide a summary of the additional advice provided in relation to entanglement risk for diving birds and the interaction of fishing activities with prey species/supporting habitats.

Advice on fishing activity

Table 1 below is a summary of NatureScot’s generic advice for relevant fishing activities for which it is possible (i.e. there is a sufficient evidence base) to provide further advice to support the development of management measures for the protected features in marine and colony SPAs in the Scottish MPA network. The advice in the table is not site-specific and does not take account of seasonal or species-specific information, all of which may change the advice at a site level. For this reason, it is important to also refer to the relevant CMA and the associated site-specific document NatureScot has produced.

We also advise the following:

• We are not providing any further advice on hand gathering, tractor dredging and bait collection.  The advice provided in the CMAs remains relevant.
• There is insufficient evidence on the interactions between demersal mobile gear and prey species / supporting habitats of gulls (except kittiwake) to support the development of site-specific measures.
• Site-specific measures for long-lining are not currently considered appropriate due to the scale of the fishery, and the wide-spread interaction with seabirds. However, there is evidence of seabird bycatch in long-line (not jigging) fisheries which we recommend require wider seas measures.

Static gear, netting, refers to those gear types where the catching operation does not require an active movement of the gear. This can include those nets which are set or anchored to the seabed (bottom set nets) and may include gill, trammel and tangle nets, or types of trap net (e.g. fyke nets). Also included in the definition are drift nets, which are gill or trammel nets suspended in the water and can occur at the surface or throughout the water column. Depending on how the nets are set and where in the water column, they may target demersal or pelagic species. Nets set in targeting these species, may therefore be referred to as demersal static nets or pelagic static nets.

Dive Depth Mapping and Analysis: Interactions with demersal static netting

Our CMAs identified entanglement as a key pressure associated with some fishing gear. To look at potential interaction with static netting, where foraging marine birds could be exposed to these gear types operating within the SPAs, analysis of the relevant dive depths of protected features was undertaken. Table 2 provides maximum dive depths for species that dive below the surface to feed in the water column and/or to feed on the seabed. Mean depths are also provided as a broad indicator of where feeding activity takes place.

The dive depths presented in Table 2 are based on a synthesis of published research undertaken by Robbins et al. (in prep.). The underlying research varies in sample sizes and is limited to small studies undertaken at individual colonies. As such caution is required when applying these dive depths across all sites as there is likely to be site-specific variation in the depths at which birds are foraging and therefore in the level of entanglement risk.

Surface feeders may be exposed to gear that operates at or near the sea surface throughout the SPA however, the risk of feature-fisheries interaction is considered to be low. Therefore, only species that dive below 0.5 metres have been included in the mapping analysis.

For each SPA the generic mean and maximum dive depths recorded for each species that dives below the surface (Table 2) were mapped. The site-specific documents provide maps which show areas within the SPAs where there is potential for exposure of protected features to relevant demersal fishing gear (demersal static nets) only (with the exception of potential exposure during deployment and retrieval). 

Mapping is most relevant to those birds which dive to the seabed to feed (see Table 2) as their dive depths can be used to determine limits to exposure. The value of mapping dive depths is however less useful for pursuit diving seabirds (Auks, shearwaters and gannet chase prey below the surface using their wings for propulsion. Cormorants and divers can use their feet to drive them forward underwater while in pursuit of prey. These diving seabirds are therefore often called “pursuit divers.”), which dive below the surface to feed and could be exposed to pelagic or midwater gear types throughout the water column of the SPA, down to the maximum dive depth specified for each species. For example, dive depth mapping for guillemot shows the areas of seabed where interactions could occur with demersal static nets, but exposure to other gear types, e.g. longlines, or midwater drift nets could occur within the water column to a depth of 177 m throughout the SPA (based on data from Robbins et al., in prep). As such whilst we recognise that those static nets which are not fishing demersally (demersal static nets) are a key pressure for marine birds, we cannot provide spatial advice for these gear types. However, our advice remains remove or avoid for these pressures within the relevant sites.

In the site-specific documents, maps are presented using the dive depths of the protected feature(s) which have the greatest maximum dive depth. The greatest mean dive depth is provided as an additional indicator of feeding activity. By mapping areas for the species with the greatest maximum dive depth in any marine SPA this will ensure the areas identified are equal to or shallower than the maximum dive depths of all protected features. It also accounts for variation between individuals within and between species (maps for all features are provided in annexes to the site-specific documents). 

For marine SPAs we recommend the removal or avoidance of pressures associated with demersal static nets over the majority of the area encompassed by the greatest maximum diving depth for the protected species of the SPA. Any seasonal elements are outlined in the site-specific advice. 

For marine extensions to colony SPAs our understanding of risk associated with static nets entanglement is less clear. The marine extensions were designated to provide protection to the marine areas immediately surrounding the colonies that are used by seabirds for maintenance and socialisation behaviours (preening, bathing, rafting etc.). They were not designated specifically to protect foraging areas, but all species are likely to feed within the relevant 1 km, 2 km or 4 km extension areas. 

There is evidence from studies on seabird mean foraging ranges that would suggest core foraging areas for most seabirds extends beyond the respective 1 km, 2 km or 4 km marine extension boundaries (Woodward et al., 2019). However, in the work to underpin the SPA marine extensions, McSorley et al. (2003) investigated bird density and behaviour between the colony and up to 5 km from the coast. Although much of the report is focused on the time spent on maintenance behaviours, the surveys also estimated the total number and frequency of feeding birds within 5 km of the colony. The formal analysis of distance bands (1 km, 2 km and 4 km) incorporates only birds engaging in maintenance behaviours, however within the 5 km study areas, feeding was regularly recorded in the behaviour of most species. Based on this data we expect seabird protected features to be feeding within the SPA marine extensions.

For SPA marine extensions we recommend the removal or avoidance of pressures associated with demersal static nets over the majority of the area encompassed by the greatest maximum diving depth for the protected species of the SPA. Any seasonal elements are outlined in the site-specific advice. The general methods used for defining the site-specific seasonal definitions are detailed in Annex 1. Site-specific analysis has been undertaken for all sites except Fetlar SPA, as there are no diving seabird protected features. This is presented in the site-specific documents.