Differences in coverage make any interpretation of changes in the locations where vessels have been based very difficult, particularly for the under 10m sector. Sudden breaks in trend, as revealed in Table 2, raise doubts about the accuracy of the figures. For instance, the apparent reduction in vessels with owners based in Orkney in 1989 and Shetland in 1990 or the dramatic increases shown at Stornoway in 1989 and 1992, Mallaig in 1988, Campbeltown in 1988 and in many districts in 1993 seem to be attributable largely to changes in data coverage rather than in the actual number of vessels. Closer scrutiny of the trends by length class (Annex 1, Table 2A) show that in all these instances it is the under 10m (30 feet) sector which is responsible for such fluctuations. The explanation seems to be the variable coverage of this sector in the Fleet Statistics prior to 1993. The 12 per cent increase in the overall number of under 10m vessels recorded between 1987 and 1989, for instance, can nearly all be attributed to the three districts of Stornoway, Mallaig and Campbeltown. The most obvious reason for this is improved recording of vessels in these districts rather than any actual growth in their locally owned fleets. For the period between 1986 and 1992 the safest conclusion to draw is that the number of small vessels in the Scottish fleet probably remained relatively constant.

Table 3, also in Annex 1, shows the average number of locally owned vessels in each district in two different time periods: 1986-1992 and 1993-1996. Averages have been used to smooth out the more extreme annual fluctuations in the recorded number of vessels and the time periods have been chosen on the basis of differences in data coverage. Each district's average share of the Scottish fishing fleet, by length class, for both of these periods is shown in the Table, and Table 4 uses Location Quotients (LQs) to compare this percentage with the district's share of all vessels in the Scottish fleet⁵.

Table 4: The Relative Importance of Length Class by District

Table 4 shows that the districts with the consistently greatest relative dependence on the under 10m fleet have been Oban, Stornoway and Wick. Other areas that have maintained an above average representation of small boats since 1986 are Mallaig, Ullapool, Orkney, Shetland, Campbeltown, Pittenweem and Arbroath. Eight of these ten districts are located in the Highlands and Islands where such vessels target stocks of shellfish, mostly using creels.

The growth in the largest sizes of vessel (over 25m), particularly since 1990, has benefited a small number of ports. The LQs show that in 1996 the ownership of such vessels was heavily concentrated into just three areas. These were Grampian (Peterhead, Buckie, Fraserburgh, and Aberdeen districts); the Shetland Isles; and Ayr base district, which had no large boats in 1990 but 23 by 1993. This sudden increase occurred as a result of Spanish owned, but UK registered vessels, moving from ports such as Milford Haven to Troon, in Ayr district, where their agent is based. These vessels mainly target hake and anglerfish in the sea areas to the north and west of Scotland so Troon was a more convenient base.

Apart from the district of Ayr, which had no large vessels before 1991, the other areas have been the principal bases for such vessels throughout the ten year period. During this time over half the fleet of large vessels has been based in the Grampian ports. The post 1992 figures in this particular time series are not comparable in absolute terms with those for the earlier period. This is because the shift from registered to overall length led to a large jump in the number of vessels being classified as large rather than medium sized.

The districts where the vessel owners have consistently been most dependent on the declining medium size sector (10<25m) have been Buckie (including Lossiemouth), Fraserburgh (including Macduff), Lochinver and Eyemouth, followed by Peterhead and Ayr. Whereas Buckie and Lossiemouth saw the number of such locally owned vessels decline during the 1986-1992 period, both Fraserburgh and Macduff districts, which are on the same stretch of coast, experienced little change in the number of medium sized boats based at their ports. However, since 1993 the rapid contraction of this fleet sector has affected these districts as well.

Those ports that are not deep enough to berth the new generation of larger and deeper draughted boats, and which lack either locally based processors or active local fish markets, have lost out from these trends. Some of the medium and large sized vessels, with owners based in the Moray Firth ports, have been moved to Kinlochbervie on the north-west coast where they are located for much of the year. Ports such as Fraserburgh, Peterhead, Aberdeen, Troon, Lochinver and those in the Orkney and Shetland Isles, which are able to accommodate larger vessels either because of natural conditions or harbour deepening schemes, have been better placed to diversify their locally owned fleet structure. Other deeper water ports such as Kinlochbervie and Scrabster, in Wick district, which are well located for the fishing grounds have been able to attract visiting vessels and this has also allowed them to take advantage of the trend towards larger vessels.

By comparing the proportion of all vessels that use a particular fishing method with the percentage of boats within a particular length class that use the same method, it is possible to identify, on the basis of a ratio greater than 1.0, which length classes make the most use of a particular method. Table 5 shows that whilst the vast majority (90 per cent) of small boats fish by using creels, a number of other fishing methods, such as other demersal, lines and other shellfish, are also over-represented amongst the small vessel sector⁶.

Table 5: Length of Vessel and Fishing Method, 1996

Amongst medium size vessels there is an above average proportion of boats that use demersal trawl and seine, nephrops trawl and suction dredge methods. In the case of the large vessel sector there is a massive over representation of beam trawlers, pelagic purse seiners and pelagic trawlers although demersal seiners, trawlers, gill netters and lines are also more numerous than expected on the basis of their share of all vessels.

It is evident from Table 5 that the three main types of fishing method are each dominated by a different size of vessel. Most (76 per cent) shellfish boats are under 10m in length; the majority (64 per cent) of demersal vessels are between 10-25m long; and the pelagic fleet consists entirely of large vessels in excess of 25m in length. Inevitably there are some exceptions amongst these broad fleet segments. Within the demersal sector, beam trawlers are generally large vessels whilst most boats that use gill nets and lines are small. The most numerous types of demersal boats are trawlers and seiners and about 75 per cent of these are in the medium length category. Within the shellfish sector most vessels that use nephrops trawl or suction dredges are medium rather than small in size.