The Distribution of Fishing Effort and Landings of Sea Fish
Figures 1.a to 6.a show the spatial distribution of fishing effort by UK vessels in Scottish waters in 2011. Fishing
effort ('days at sea') is the time that vessels spend at sea, it may be measured as the total time spent at sea (in
hours or days) or as in the accompanying maps, by a calculation multiplying the engine power of the fishing
vessel by the time at sea and expressing this in kilowatt-days. As part of the management of Scotland's fishing
opportunities restrictions exist on fishing effort by vessels 10 metres or over that use particular types of fishing
gear. For each gear type the effort map is shown alongside maps of the quantity of sea fish caught in Scottish
waters in 2011 by both UK vessels and foreign vessels that land into the UK (figures 1.b to 6.b)1. Quantity
represents the liveweight landings of sea fish (in tonnes) caught within each International Council of the
Exploration of the Sea (ICES) statistical rectangle. The change in fishing effort between the year 2000 and 2011
and the change in the quantity landed for these two years are displayed in figures 1.c to 6.c and figures 1.d to
6.d respectively.
Effort (kwdays) by gear type in 2011
Other non-regulated
gear
4%
Pots
19%
TR1 (Whitefish)
22%
Dredge
9%
Pelagic
8%
Other regulated gear
1%
TR2 (Nephrops)
22%
BT1 & BT2 (Beam Trawl)
8%
GN1 & LL1 (Nets and
Long Lines)
7%
Whitefish (TR1) Gear2
Vessels using gear type TR1, which includes bottom trawls, seines and similar towed gears, excluding beam
trawls, of mesh size equal to or larger than 100mm are typically used to target whitefish. Effort deployed by
these vessels is concentrated in the northern North Sea, near to the continental shelf edge to the north and
west of Scotland, and around Rockall (figure 1.a). The distribution of landings generally reflects this effort
distribution (figure 1.b).
1
It should be noted that the distinction between effort and landings maps, with the former being UK vessels in Scottish waters and the
latter being tonnage caught in Scottish waters landed by UK or foreign vessels, means the two are not fully comparable.
2 Further information on gear type is provided in the entry for the ‘Cod Recovery Zone’ in the Glossary of terms in the Scottish Sea
Fisheries Statistics 2011.
A comparison of effort by vessels using whitefish (TR1) gears between 2000 and 2011 shows a considerable
decrease (figure 1.c). This decrease mainly reflects the impact of the two decommissioning schemes in 200102 and 2003-04 which removed 165 vessels from the Scottish whitefish fleet. Also, since November 2008, the
revision of the Cod Recovery Plan, introduced to protect weakened cod stocks in European Union waters, has
applied successive decrements in fishing effort on gear categories that are considered most important to cod
mortality. The aim of effort restrictions is to limit cod mortality and seek recovery of the cod stock. With the
exception of Rockall, which is outside the cod recovery plan effort restriction zones, there has been a
cessation of effort in areas furthest from Scottish ports (figure 1.c). Vessels may prefer to conserve effort by
shortening the length of time spent travelling to fishing grounds by fishing closer to land. High fuel prices
could also be contributing to the cessation of effort further afield. Changes in quantities landed between 2000
and 2011 generally reflect the changes in effort, though landings have decreased less (or even increased) than
the changes in effort (figure 1.d).
Nephrops (TR2) Gear
Gear type TR2 includes bottom trawls, seines and similar towed gears, excluding beam trawls, of mesh size
equal to or larger than 70mm and less than 100mm. These gears typically target Scottish langoustine
(Nephrops) and fishing activity by these vessels, represented by both effort and quantity of landings is
concentrated in the Moray Firth, the Firth of Forth, the Fladen ground (an area in the northern North Sea), and
along the west coast of Scotland (figure 2.a and figure 2.b). This distribution of fishing activity by Nephrops
vessels reflects the distribution of muddy sediment suitable for Nephrops to construct burrows in which they
spend most of their time, only coming out to feed and look for a mate.
Comparing fishing activity in 2000 with activity in 2011 there has been an increase in effort and the quantity of
landings from the North Sea and the south west of Scotland (figure 2.c and figure 2.d). Rockall and locations at
a distance from the coast, with the exception of the Fladen ground, have seen a sharp reduction and, for some
rectangles, a cessation in fishing activity. This reduced activity may result from commercial decisions by
fishermen balancing Nephrops availability and fuel costs.
Gill Nets and Long Lines Gear
Effort by vessels using gill nets (GN1) and long lines (LL1) is concentrated close to the 200m depth contour
which includes the edge of continental shelf to the north and west of Scotland, with a small amount of effort
deployed around Rockall (figure 3.a). Corresponding large quantities of landings are captured from these
relatively high effort areas (figure 3.b).
Fishing activity, in terms of effort and quantity of landings in 2011 compared with 2000 has become more
focussed along the shelf edge, while fishing activity has reduced or ceased in locations away from the shelf
edge (figure 3.c and figure 3.d).
Pelagic Gear
Vessels using pelagic gears which include mid-water trawls and surrounding nets (purse seines) deployed their
effort in 2011 mainly in the northern North Sea, with some effort in the waters to the west of Scotland
(figure 4.a). The large size and efficiency of Scottish pelagic vessels means that large quantities of pelagic
landings are captured for relatively low effort compared with the effort invested and quantity of landings
achieved by vessels using other gear types (figure 4.b).
Comparison of the distribution of effort and quantity of landings in 2011 relative to 2000 show a mix of areas
where fishing activity (effort and landings) has increased and areas where activity has decreased (figure 4.c
and figure 4.d). While there are general patterns to the migratory route of pelagic fish travelling between their
feeding grounds and spawning areas, the exact route and timing of migrations may vary from one year to the
next.
Dredges
Dredging is essentially an in-shore activity targeting scallops with vessels using dredges being active close to
the Scottish coastline (figure 5.a and figure 5.b). The majority of dredge effort is deployed near Shetland,
south west Scotland and south east Scotland. Dredges capture large quantities of landings for relatively low
effort compared with the effort invested and quantity of landings achieved by vessels using static gears,
namely creels (pots).
Dredging effort in 2011 has generally decreased relative to effort in 2000 except for those areas near to
Shetland, Orkney, the north east of Scotland and inshore to the east of Scotland (figure 5.c). However, there is
some indication that dredging effort to the east and south west of Scotland has become more efficient as the
quantities landed has increased in spite of decreases in effort (figure 5.c and figure 5.d). Efficiencies can be
achieved through vessels deploying larger numbers of dredges (though subject to restriction in certain areas),
and the exploitation of more prolific scallop beds.
Pots/Creels
Effort by vessels using creels (pots) is predominantly an in-shore activity, concentrated close to the Scottish
coastline with some additional activity on the continental shelf to the north of Scotland (figure 6.a).
Correspondingly large quantities of landings are captured from these inshore areas and the continental shelf
(figure 6.b).
Comparing effort in 2011 with that deployed in 2000 indicates an increase in inshore areas and cessation from
areas further afield and off the shelf edge (figure 6.c). Increases and decreases in the quantity of landings
reflect these changes in effort (figure 6.d).