Scottish Marine and Freshwater Science Volume 3 Number 3
6. HUMAN IMPACTS FISHERIES 6.1 Introduction
The fishing industry has had a major impact on the image and character of the Firth of Clyde and many of its coastal towns. It is a complex, traditional industry and holds great economic importance for many rural communities around Scotland’s coast, including the Clyde, as well as political influence (SSMEI, 2010). In the Clyde, fishing occurs throughout the area and the main landing ports are Campbelltown, Tarbert, Ayr and Troon and some smaller fishing ports, Greenock, Largs and Rothesay. The Clyde had once been a productive fishery for demersal, pelagic and shellfish but is now primarily a shellfish fishery. The locations of the main fishing ports in the region where landings have been recorded are shown in Figure 6.1.
Figure 6.1 The locations of the main Clyde fishing ports where landings have been recorded. The principal fisheries management legislation Acts that are applicable to the Clyde are included in Table 6.1. The list should not be considered a comprehensive list and does not include the statutory instruments implemented under the different acts throughout the years.
Table 6.1 The principal fisheries management legislation Acts that are applicable to the Clyde. The list should not be considered a comprehensive list and does not include the statutory instruments implemented under the different acts throughout the years.
Year Title 1885 Sea Fisheries Scotland Act 1891 Fisheries Act 1893 North Sea Fisheries Act 1915 Fishery Harbours Act 1934 Illegal Trawling Act 1955 Fisheries Act 1962 Sea Fish Industry Act 1964 Fishery Limits Act 1966 Sea Fisheries Regulation Act 1967 Sea Fisheries (Shellfish) Act 1967 Sea Fish (Conservation) Act 1968 Sea Fisheries Act 1970 Sea Fish Industry Act 1973 Sea Fisheries (Shellfish) Act 1976 Fishery Limits Act 1984 Inshore Fishing (Scotland) Act 1992 Sea Fisheries (Wildlife Conservation) Act 1992 Sea Fish (Conservation) Act 1994 Inshore Fishing (Scotland) Act 2000 Sea Fisheries (Shellfish) Amendment (Scotland) Act 2005 The Registration of Fish Sellers and Buyers 2009 Marine and Coastal Act 2010 Marine Scotland Act Some of the legislation changes have had a profound effect on the behaviour of the fisheries such as following the introduction of the Buyers and Sellers registration in 2005 which resulted in an almost complete stop to black landings around Scotland. However, since the Buyers and Sellers regulation there has also been a dramatic increase in the levels of discarding of finfish across all age groups suggesting that the legislation has controlled landings rather than catch.
A ban on trawling in the Clyde was originally introduced in the late nineteenth century after fishery scientists at the time suggested that the Firth of Clyde fisheries were becoming depleted due to excessive trawling (Thurstan and Roberts, 2010). The Act was then amended in 1934 to include beam and otter trawling under the Illegal Trawling (Scotland) Act 1934. The closure remained in place until 1962 when the Sea Fisheries (Scotland) Byelaw (No.65) came into effect which permitted summer (1 May to 30 September) otter trawling within the Firth of Clyde except within a 3 nautical mile limit (Figure 6.1). Further legislation in 1968 (Sea Fisheries (Scotland) Byelaws no.’s 80 and 83) enabled fishing to take place throughout the year. The 3 nautical mile limit remained until 1984 (Inshore Fishing (Scotland) Act) when it was repealed under pressure from the industry during a time when demersal finfish landings were in decline. Sea angling was at one time a major sport and tourist attraction in the Clyde, which began in the 1960s. However, with the decline in catches sea angling in the Clyde is not what it used to be. SSACN blame poor fisheries policies and practices combined with political ineptitude, resulting in the removal of many gear and access restrictions in the 1980’s, to be the reason that the quality of sea angling has drastically declined. This suggestion was further supported by Thurstan and Roberts (2010) which linked the collapse of the demersal fisheries in the Clyde with the removal of the 3 nautical mile closure.
With regards to legislation applicable to the herring fishery in the Clyde, it was also prohibited to pelagic trawling for herring until 1962. In the same year a Byelaw was passed which prohibited fishing for herring by any method between midnight on Fridays and midnight on Sundays. The spawning ground for herring located on the Ballantrae Bank had originally been closed in 1860 but this was repealed in 1867. The bank stayed open to fishing until 1972 when a seasonal closure was introduced from 15 February until the 30 April each year. There was an exemption for anchored drift nets but they became included in the seasonal closure in 1977 (Bailey et al., 1986).
The measures which remain in force in order to protect the spring spawning herring are as follows;
a complete ban on herring fishing from 1 January to 30 April a complete ban on all
replica ray bans forms of active fishing from 1 February to 1 April on the Ballantrae Bank spawning grounds a ban on herring fishing between 00,00
replica ray ban sunglasses Saturday morning and 24,00 Sunday night. 6.3 Stock Assessment
ICES provides scientific advice on the management of the important commercial species of fin fish and some shellfish stocks in all areas of the north east Atlantic. For the purpose of assessment, ICES divide sea areas into sub areas and divisions. Annual Total Allowable Catch (TAC) quotas are agreed for each of the fisheries in each division. Ideally these are based on scientific advice which is given in accordance with the precautionary approach and aimed at keeping stocks above the reference point of Bpa (if this is defined for the stock). This work is summarised in the annual ICES advice. ICES is responsible for providing scientific advice on TACs and other conservation measures to the international fisheries commissions, including the EU. In addition, since 2010 ICES has given advice in relation to Maximum Sustainable Yield (MSY).
The Firth of Clyde falls into Division VIa which stretches from the North Channel of the Irish Sea to 60N and west to 12W including the coast of Scotland as far east as 4W including the Clyde. For the main demersal species stock assessments are carried out at the level of VIa. Thus assessment and setting of Total Allowable Catches is carried out at the level of the ‘West of Scotland’ rather than the Clyde. The main exceptions to this are Clyde herring, Nephrops and scallops, which are assessed locally.
6.4 Pelagic FisheriesThe Firth of Clyde was once the centre of a major herring fishery which had been prosecuted in Scottish inshore waters since the 15th century (Rorke, 2005) although it has been subject to major fluctuations (Bailey et al., 1986). The biology of the Clyde herring stock has been studied since the late 1800’s following the opening of a temporary laboratory at Tarbert, Loch Fyne (Gordon and De Silva, 1980). In the past the fishery was almost entirely dependent on spring spawning herring which spawn locally on Ballantrae Bank in the Firth of Clyde until about 1969 when a new component of autumn spawning herring gradually increased in importance in landings and was predominant by 1972 (HAWG, 1978). Although autumn spawned herring formed a greater part of the Clyde population, there was no evidence of autumn spawning occurring within the Firth (Wood, 1960; Saville, 1962).
Although there had been no significant change in the abundance of the total herring population, the spring spawners had decreased in the early 1970s which was accompanied by an increase in the absolute abundance of autumn spawners. In 1979 TAC regulations were imposed on the stock in addition to a closure of the fishery from October through till May in response to the clear evidence of a decrease in the abundance of spring spawning herring (Bailey et al., 1986). The cause of this decline may be natural as it can be attributed with the reduced recruitment of the local spring spawning stock, but the effects of intensive exploitation cannot be ruled out (Bailey et al., 1986).
In Scotland, records of herring landings were kept even before the Fishery Board for Scotland was formed in 1882. The fishery was prosecuted by anchored drift net and ring netting until pair trawling arrived in 1968 and became the predominant method by 1973 (Bailey et al., 1986). Catches increased to a peak between the late 1950s and mid 1960s averaging around 14,000 t per annum after which the stock began to collapse (Bailey, 1986) (see Figure 6.2).
The Firth of Clyde is part of ICES Division VIa and in the 1970s all the herring stocks in the adjacent areas to the Clyde were at a low level. This led to Division VIa herring fishery being closed in 1978 but because of the complex origin of the Clyde herring population, ICES advised that the area be treated as a separated management unit. A small TAC of 2000t was agreed in 1979 for the area (Bailey et al., 1986) and the first analytical assessment was carried out in 1982 (Hatfield et al., 2007). Management of the Clyde has remained separate since 1979.
Landings of herring from the Firth of Clyde fluctuated about a long term average of 14,200t in the period 1893 1960, from 1960 1978 the average landings were down to 8300t and only 2400t from 1978 1984 when landings became regulated. Since 1991 catches in the Clyde have exceeded 1,000 t only once (see Figure 6.3). The reasons for the collapse of the Clyde
discount ray bans herring are not clear cut however declining spawning stock biomass, high fishing mortality and lack of recruitment to the local spring spawning stock may well have been causative (Bailey et al., 1986).
Figure 6.2 Herring landings in the Firth of Clyde (1000 tonnes) 1890 1984 (Source, Bailey et al., 1986).
Figure 6.3. Herring landings (1000 tonnes), 1955 to 2009. Spring and autumn spawning herring combined. Agreed TAC 1984 2009.
Today herring in the Clyde are exploited by a small number of local trawlers and by pair trawlers from Northern Ireland. There is not much information on the current status of the stock as catch and sampling data availability has been minimal since the early 2000s. Thus, the precise status of the stock is uncertain; the stock is low but there is currently no evident downward trend. The Clyde herring stock is recognised as a separate stock but is not currently assessed analytically.
In 2011 under the provisions of the TAC
cheap ray bans and Quota Regulations (57/2011), the European Commission has delegated the function of setting the TAC for certain stocks which are only fished by one Member State, to that Member State setting out a mechanism for how the TAC should be determined. This provision currently applies only to the Clyde Herring stock. However, as mentioned, Clyde Herring is a very data poor stock which makes this task more difficult. It has been proposed, in the absence of a detailed assessment, to set the TAC for 2011 based on the recent stability of the fishery at an average of the TAC set for the last 3 years.
Despite the management measures imposed on the Clyde herring fishery such as the closure of the spawning fishery, there is so far no evidence of recovery of the recruitment to this stock.
6.5 Demersal Fisheries
In the Clyde yields of demersal fish increased rapidly after the repeal, in 1962, of the long standing ban on trawling in the area up to 3 nautical miles from the coast. The demersal fish landings continued to increase up until 1973 when landings reached a maximum before starting to decline (Hislop, 1986). In 1984 the 3 nautical mile ban was also lifted in order to try and maintain catch levels. This proved ineffective and demersal fin fish landings continued to decline until the early 2000’s when the directed fishery effectively ceased (Heath and Speirs, 2010). In addition, the total demersal fishing effort in the Clyde had risen since the 1960’s almost entirely due to an increase in trawling for Nephrops from which there was a large by catch of whitefish. According to the Scottish Sea Fisheries Statistical Tables (SSFST), which were published annually by DAFS, the annual weights of all demersal species landed at Clyde ports, in the early 1980’s, ranged from 4,000 to 10,000 tonnes, valued at 2 5 million. In terms of value, cod and hake were the most important species in the Clyde fishery; these species composition of landings in the Clyde are unusual for a Scottish inshore fishery in that the proportion of haddock is rather small, while that of hake is relatively large.
The demersal fishery was seasonal on the Clyde grounds and most of the fishing effort took place during the winter and spring, partly because catch rates were relatively high at this time of year and partly because the area provides shelter from the winter weather. The Clyde fishery depends to a large extent on young fish and the relative importance of the principle species fluctuates from year to year in response to variations in the strength of the recruiting year class. Although there was no conclusive evidence that the Clyde populations were self contained, all the major species are known to spawn within or close to the area and tagging experiments had shown that there was not much mixing between Clyde fish and those from surrounding areas. Historically, the most important single species in the Clyde demersal fishery in terms of landings has been whiting (Gambell, 1965).Articles Connexes：