2 Case for a Marine Protected Area in Fair Isle Waters

2.1 Human benefits

The wider benefits of managing the marine area for conservation purposes are integral to this study and would be vital to the success of its recommendations. A second report, by The National Trust for Scotland, is planned to address these wider issues of concern.

2.2 Protection afforded by existing SPA

However, this protection does not extend to the surrounding marine area. At sea, measures to prohibit the capture and killing of these birds still apply, but there are no restrictions on human activities detrimental to seabirds other than those applied under other statutes or regulations. Some of these may, indirectly, be beneficial to seabirds but are applied for other reasons – normally in relation to fisheries. No strategic management framework exists to ensure ecologically sustainable development within the outlying marine environment.

The following sections outline the salient factor affecting Fair Isle’s breeding seabird populations – the size and composition of sandeel stocks – to demonstrate the need for a marine protected area.

2.3 Sandeel stocks in Fair Isle waters

The seas off Fair Isle are an important spawning ground for sandeels. The combination of a preferred substrate (Del Nevo, 1990) and strong tidal flow in waters less than 80 m deep (Tasker et al, 1997) provides an apparently ideal environment for sandeels within 4–5 km, which in years of abundance occur in the water column from about April to July (and in smaller numbers from January to October).

The combined findings of two research studies suggest that Fair Isle and Shetland may support discrete sandeel populations. Del Nevo (1990) found differences in guillemot population trends between Fair Isle and Shetland, suggesting different food sources: the Fair Isle population increased at a time of mean annual decrease on Shetland, and Fair Isle chicks showed better growth rates. This is lent further weight by the fact that his study birds foraged mainly within 5 km of Fair Isle. Wright and Bailey (1993) found separate sandeel spawning areas in Shetland and the Fair Isle Channel, but also identified larval advection from the latter stock to the former. They concluded that Shetland sandeel stocks are more fluctuating than the Orkney-Fair Isle stocks, and are perhaps dependent on pulses of recruitment from the Fair Isle Channel.

The distance that seabirds forage is a cost to both the adult (in energy expended) and to the chick (in growth rates). The better performance of Fair Isle guillemots emphasises the importance of an abundant food source close to the breeding site. The differences between Fair Isle and Shetland guillemots indicate that sandeels are relatively more abundant at Fair Isle (at least during the period of Del Nevo’s work). This highlights the conservation importance of Fair Isle waters.

2.4 Relationship between Fair Isle seabirds and sandeels

Sandeels are of relatively high energy value, and are therefore an important food source for seabird chicks (Harris & Hislop, 1978). Studies on Fair Isle indicate that sandeels are a major food source for fulmar, shag, kittiwake, guillemot, razorbill, puffin, Arctic skua, great skua, common tern and Arctic tern (Harris & Riddiford, 1989; Riddiford, 1993; Riddington, 1995; Riddington et al, 1996). This is also the case elsewhere in Shetland (Furness and Todd, 1984; Furness, 1989; Martin, 1989). The calorific value of sandeels is significantly different between age classes (Del Nevo, 1990) and larger sandeels are chosen preferentially by most seabirds (although a range of sandeel sizes is required for chicks of different ages and species). In years when older age classes were not a major food item, some seabird species experienced low breeding productivity or complete failure. In those years, fewer sandeels in the older classes were caught by fishing fleets off Fair Isle, suggesting that the quantity and age classes of sandeels fed to seabird chicks are determined by availability.

Riddiford (1993) used data collected by Fair Isle Bird Observatory to demonstrate a relationship between Fair Isle's seabird population dynamics and sandeel availability. A study of sandeel abundance in Shetland waters showed that stocks increased strongly from 1974 to reach a peak in 1982–83 (Kunzlik 1989). Fair Isle breeding populations of fulmar, gannet, great skua, common gull, kittiwake, common tern, Arctic tern, guillemot and razorbill increased to at least the 1980s. Eight of these species have been shown to rely on sandeels as a food source for chicks. (This has not been proven for common gull, although this could be presumed to be the case as sandeels have been recorded in the diet of coastal common gulls at Murmansk (Cramp & Simmons, 1982), and adult common gulls on Fair Isle predominantly forage at sea (N. Riddiford, pers obs).) Thus, for these nine species, marked population growth and (in the case of gannet, common gull, common and Arctic terns) colonisation of Fair Isle may have been a direct response to increased availability of sandeels.

The only seabird species on Fair Isle to maintain high rates of population growth throughout the 1980s and into the 1990s are fulmar, gannet and Arctic tern (Riddington et al, 1996). However, two of these species (fulmar and gannet) have been shown to exploit food sources other than sandeels. The increase in fulmar populations is widely linked to the provision of offal and discards from fishing boats. (Although counts during the major sandeel shortage suggest that the population increase slowed to about 3% growth.) A study on Shetland demonstrated that gannets respond to changes in prey availability by replacing sandeels with herring and mackerel as a major food item for their chicks (Martin, 1989). Samples collected from Fair Isle colonies since 1989 confirm that Fair Isle gannet chicks are also being fed herring and mackerel (Harvey et al, 1989; Riddington, 1995; Riddington et al, 1996). The increase in Arctic terns mainly involved mid-season immigration from Shetland, and very few young were raised before 1991 (Riddington et al, 1995). From 1983 to 1990, Arctic tern breeding productivity at Shetland colonies was virtually nil (Monaghan & Uttley, 1989). Therefore, recruitment to the small Fair Isle colony may have occurred after early failures on Shetland; limited ringing recoveries suggest that this may indeed be the case (R. Riddington, in litt). Thus, the increase in the Arctic tern population can still be linked to sandeel availability.

For other breeding seabirds on Fair Isle, population growth during the 1980s either slowed considerably (kittiwake), ceased (shag, great skua, common gull, guillemot, razorbill and puffin) or was reversed (common tern). This suggests that the breeding populations of most of these species were strongly linked to the declining sandeel stocks. However, the extent to which other factors may also have influenced population trends is unknown. For example, great skuas were able to turn to other food sources during the sandeel crash, and breeding productivity remained good during 1989–90 (Harvey et al, 1989 and 1990). The provision of offal and discards by modern fisheries is also an important factor, especially for fulmar and kittiwake (Camphuysen et al, 1995).

2.5 Need for integrated management

The two previous sections have established the importance of sandeels stocks to Fair Isle’s breeding seabird populations. As the hazard evaluation in Chapter 3 shows, this is highly significant to the conservation objectives of the proposed protected area. Thus, the impact of commercial fisheries is a very important consideration for any management measures.

In the North Sea, total sandeel landings, apparently reflecting expanding biomass, increased dramatically during the 1960s and 1970s. The increase is thought to have been caused by overfishing of their trophic predators and, in some cases, food competitors – notably herring and mackerel (Sherman et al, 1981; Furness, 1984). However, in recent years commercial fisheries have turned to the species sought by most seabirds (ie sprats and sandeels), which have therefore started to come into competition (Furness, 1984). This is most clearly illustrated in north-west Norway where the collapse of the spring herring fishery, aggravated by a reduction in availability of sandeels, was directly responsible for the total breeding failure of the puffin population on Röst (Lid, 1981).

Attributing fish stock depletion to the impact of commercial fisheries is difficult, as fish populations are subject to complex natural trends. For example, climatic changes may influence biological parameters within the marine environment (Heath et al, 1996). Nevertheless, food availability for seabirds is determined by the size and distribution of fish stocks and, in fragile environments, commercial exploitation of these stocks may be an additional negative factor. This reinforces the need for a more integrated approach to managing Fair Isle’s surrounding marine environment, in respect of both the objectives of the existing SPA and in the search for greater sustainability in fisheries management. A marine protected area would address this need.

2.6 Summary

The existing consensus behind the case for a marine protected area surrounding Fair Isle stems from concern at an apparent lack of sustainability in the current use of its marine environment. There are a number of reasons why Fair Isle waters merit protection:

1. Fair Isle supports breeding seabird populations of international importance.
2. Waters adjacent to Fair Isle rank as the second most important area for seabirds in the North Sea, based on the number of species occurring in the area at internationally important levels (Skov et al, 1995).
3. The existing SPA affords only terrestrial protection to these seabird populations.
4. Fair Isle’s breeding seabird populations have been studied by Fair Isle Bird Observatory since 1948, and monitored systematically as part of the JNCC UK Seabird Monitoring Scheme since 1986.
5. A number of seabird species breeding on Fair Isle have suffered low breeding productivity in some recent years, which has been linked to shortages of a major prey item (sandeels).
6. Fair Isle supports a community with a long history of culture and traditions linked to the marine resource.
7. Fair Isle's natural heritage (and especially its seabird populations) is a key factor in attracting visitors: tourism is central to the island's economic base.
8. The concept of a marine protected area has the enthusiastic backing of the entire Fair Isle community, the landowner and other user groups.
9. The Fair Isle community has already taken a lead in seeking action to replace over-exploitation of the marine resource with integrated management for sustainable use of the marine environment.
10. The Fair Isle Marine Environment and Tourism Initiative will provide an administrative framework for targeted action by the community and other partners.

    

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Last modified: February 05, 2002