3 Case studies on the fishing efficiency and financial performance of fishing vessels

3.1 Efficiency changes in the faeroese pair-trawler fleet

B. Thomsen

3.1.1 Introduction

One of the main objectives in most marine resource management regimes around the world is to keep the harvest at a sustainable level and thereby secure a long-term utilization of the resource. Preferably the stock should not only be kept within biological safe limits but an optimum economic return from harvesting the fish resource should also be achieved.

Two types of marine resource management regimes can be identified: one is output controlled (catch quotas) while the other is input controlled (effort quotas). Both types have their strengths and weaknesses.

A question that has attracted increasing interest with regard to marine resource management systems is the rate of technical progress that increases the efficiency of fishing vessels over time. In the European Union (EU) third multiannual guidance programme (1993-96), with the ultimate objective of reducing fishing capacity to bring it into line with sustainable catches, the increase from this kind of efficiency has been assumed to be 2 percent annually (Banks et al., 2002).

In an output-controlled system the effect of an increase in vessel efficiency is self adjusted, whereas in an input-controlled system a range of input variables that are not readily controlled can result in an efficiency increase that will undermine the management regime. An example of an input-controlled system, where the question of an increase in efficiency has been raised, is the management regime in the Faeroe Islands. In this system, where a fixed number of fishing days are allocated to fishing vessels, it is of utmost interest to know whether the efficiency of single vessels will change over time or not. In the following paragraphs, data from a particular fleet segment working in the Faeroese area are examined to identify possible efficiency changes over time.

The present text was prepared as a working document for the FAO/International Council for the Exploration of the Sea (ICES) Working Group on Fishing Technology and Fish Behaviour, which met in Gdynia, Poland in April 2004 (FTFB, 2004). The text is reprinted here in a slightly extended version.

3.1.2 Faeroese marine resources and the current management regime

The Faeroe Islands are an autonomous group of islands in the Northeast Atlantic at 62°N, 7°W. The economy of the islands is totally dependent on fisheries. The most important demersal fish species in Faeroese waters are cod (Gadus morhua), haddock (Melanogrammus aeglefinus) and saithe (Pollachius virens), of which a total of between 43 676 and 119 441 tonnes have been harvested each year since 1990 (see Table 1).

From 1994 the Commercial Fishery Act has regulated the harvest from marine resources in the Faeroe Islands. The main objective is to secure biological and economical sustainability, but socio-economic factors are also considered. To achieve the main objective, one aim is for a maximum of 33 percent on average in numbers to be taken from each stock every year.

Fish stocks are harvested by a wide variety of fishing vessels using different fishing gear techniques. The fishery is a mixed fishery where cod and haddock are mainly taken by longline and trawl, while saithe is mainly taken by pair trawl (Figure 2).

In addition to technical measures such as minimum mesh size and closed areas, the fishing activity is controlled by effort quotas given as fishing days to various groups of fishing vessels and from larger vessels to single vessels within the groups. The system, which has been in effect since 1 June 1996, was originally based on an assessment of the fishing power of each vessel group according to a data series from 1985 to 1994. The Committee on Fishing Days advises the Minister on the number of fishing days to be allocated for each fishing year, which runs from 1 September to 31 August. The Fisheries Laboratory also advises the Minister on the state of stocks and on adjustments of fishing effort.

A question that arises every year when fishing days are allocated is whether the efficiency of a single fishing vessel has increased over time or not. If the efficiency has increased, the fishing days should be decreased accordingly to maintain the same pressure on the stocks. Since the introduction of the system in 1996 the number of fishing days has been reduced by 16-17 percent.

In its advice for 2003-2004, the Fisheries Laboratory referred to the ICES, which estimated the pressure on the cod, haddock and saithe stocks to be 42, 33 and 29 percent respectively. However, as a result of precautions against low recruitment and low growth, a more correct pressure for the three stocks of 27, 20 and 22 percent respectively was suggested. The recommendation therefore was a 25 percent reduction in fishing days over the next two to three years.

On the other hand, the Committee on Fishing Days did not recommend any further reductions on fishing days during this period.

3.1.3 Pair-trawler data

One of the largest vessel operators working in the Faeroe Islands is the company BETA. In the late 1970s this company invested in eight sister ships with steel hulls (37.7 metres long) and 1 200 horsepower engines. The eight vessels operated as single trawlers for a couple of years, but were then converted to four sets of pair trawlers.

The company has been very keen to keep track of all statistics concerning landings (catch) as well as economics. Information on all technical changes during the 25-year working period is also available. Agreement has been made with the vessel owner to computerize all these data for future scientific analysis. In addition to the records kept by the vessel owner, logbooks from the vessels have been handed in to the authorities. As these logbooks, together with the information from the vessel owner, are thought to be a valuable data series, the Faeroese Fisheries Laboratory has made a particular effort to validate and upgrade the logbooks. This has resulted in a high-quality logbook database with variables on single hauls, such as towing time, position, depth, weather and skipper estimates of catches per species. Unfortunately, despite specific efforts, the logbook data do not fully cover all activities of the vessels. The vessel owner has catch records from 1979 to the present, while the logbook database has data from 1985 onwards. From 1985 to 1995 the logbooks correspond to 80-100 percent of the catches, whereas from 1995 the logbooks correspond well to the total catches recorded by the company.

For the years 1985 to 2002, the database holds 45 986 records on individual hauls taken by the eight sister vessels. When hauls outside the Faeroese area and hauls with low-quality data were excluded (no towing time, no catch reported, etc.), 38 721 records were able to be used for the present analysis. In 28 062 records the catch was more than 60 percent saithe.

As the data from the vessel owner are not yet fully computerized, the following analysis is mainly based on the logbook database, but with some input from the vessel owner.

Conversion to pair trawl

Following the dramatic increase in oil prices during the 1970s many Faeroese trawler operators converted their vessels from single trawling to pair trawling as this seemed to be economically advantageous. From 1 March 1981 to 10 January 1983 all eight BETA trawlers converted from single trawl to pair trawl. The 107-120 foot (32.6-36.6 metre) "box" trawl used while single trawling was replaced by a 250-foot (76-metre) "balloon" trawl used for pair trawling. As part of a Nordforsk (cooperation between institutes in Nordic countries) project on "Energy and fishing", the fuel consumption before and after conversion to pair trawling was systematically recorded. Fuel consumption per vessel decreased from more than 3 000 to 2 000 litres per day (see Figure 3).

The conclusion from the vessel owner was that they kept the same landings but saved 40-45 percent on fuel. By getting rid of the trawl doors there was a reduction of about 15 percent on fishing gear expenses.

Converting from single trawl seems to be an example of an efficiency increase that improves the economics of the fishing operation without exerting more pressure on fish stocks.

The saving in oil was more than expected, probably because pair trawling at that time was conducted at a lower speed than single trawling. Vessels increased towing speeds during the 1990s (see below). This invites future analysis (e.g. kg fish/litre fuel) as to how economics and impact on fish stocks have changed.

Catch, CPUE and stock

Total landings from the eight sister vessels are shown in Figure 4 (left) and the catch per unit effort (CPUE) (kg/hour) per pair is shown in Figure 4 (right).

Saithe is the most important fish species for all eight vessels. In the mid-1980s and especially in 1996-97 the vessels had increased landings of cod. In 1998 one pair made a few trips targeting argentines.

The CPUE has changed dramatically over the period. From 1985 to 1991 it nearly halved but has increased to a record high in recent years.

One way to express the efficiency of a fishing vessel is to compare the CPUE to the stock size of the relevant fish species. In Figure 5 the CPUE of saithe (left) and cod (right) divided by the respective spawning stock size is plotted per year.

Efficiency on saithe went up in the mid-1990s and then went down below previous levels. In the last three to four years the efficiency on saithe has reached the same level as it was in the late 1980s. The efficiency on cod increased in the mid-1990s and has decreased since, but is still above the level of the late 1980s.

The pair that is most efficient on saithe is less efficient on cod and vice versa, probably because of differences in fishing strategy.

Tow duration and trawling hours per day

A fishing day can be divided into time when towing and time when handling the gear. To increase fishing efficiency the towing time should be maximized while the handling time should be minimized.

The average time length of a tow and the time between tows are shown in Figure 6.

The vessels have increased their tow lengths systematically since the early 1990s. One limiting factor in tow length is the trade-off between tow length and fish quality.

The time between tows has stayed around one hour, but since mid-1995 one pair has succeeded in lowering the handling time by approximately ten minutes. One explanation for this may be a lower wire/depth ratio.

In 1988 two pairs installed new trawl winches. It is stated by skippers that this reduced the hauling time considerably. This is partly verified by logbook data.

To increase the towing time from five to seven hours per tow and keeping the time between tows at one hour increase the effective fishing time per day from 20 to 21 hours or by 5 percent. The increase in tow length cannot be said to be a reaction to effort limitation since this trend was initiated before the introduction of the present management regime.

Change in trawl gear and speed

When pair trawling started in the early 1980s, the gear used was a 250-foot (76-metre) headline length "balloon" trawl with a circumference of 645 x 200 mm meshes. In the mid-1990s most vessels converted to a "Bacalao" trawl with a circumference of 630 x 160 mm. The headline and footrope length is approximately the same, which means that the meshes are more open. The fishing efficiency seems to be similar, but the tearing of the net is much less.

In the early 1990s the groundgear changed from rubber half-bobbins to rockhopper types. The weight (in air) of the groundgear has increased gradually over the years from 20-30 kg/m to 80-100 kg/m. The weight of the chains in the front of the wings has increased gradually from 5 kg/m to 22 kg/m and the weight (clump) at the bridle end (instead of the trawl door) has increased from 600 to 1 600-1 800 kg.

According to skippers, the towing speed used in the early 1980s was less than 3 knots. In the early 1990s it had increased to 3.5 knots and has now increased further up to 4 knots. An increase from 3.5 to 4 knots in towing speed corresponds to a 14 percent increase in swept area per hour. The higher speed does not only affect the swept area, but will possibly increase the efficiency of the trawl towards fast swimming fish species such as saithe. Although the logbook data include (from 1995 onwards) information on position (latitude, longitude) at start and stop of a tow it has not been possible to verify any changes in towing speed. The reason for this may be that only end positions are available and most of the tows are not straight lines. The lack of information on gear and towing speed changes in the logbook data indicates a weakness in this data-collecting system.

Symmetry sensors

From a questionnaire survey among Faeroese skippers, electronic aids are expected to improve considerably efficiency in the catching process (Jákupsstovu, Olsen and Zachariassen, 2001). It appears that global positioning systems (GPS) and plotters can increase the fishing power of a fleet by 12 percent (Robins, Wang and Die, 1998). According to the vessel owner, the electronic aid installed on the trawl in recent years - the Scanmar symmetry sensor - seems to have had the greatest impact on the success of fishing. The four pairs of trawlers received these sensors on 17 November 2000, 3 August 2001, 20 October 2001 and 29 October 2001 respectively. As almost a year passed from the first to the last installation a possible effect on fishing might be seen while comparing the efficiency between pairs. In Figure 7 an index for the catch per hour for one pair against the catch per hour for the three other pairs is plotted.

Pair 1 installed the sensor almost a year before the other three pairs, but in this period the relative efficiency did not improve, but rather the opposite.

From the index comparisons some other interesting aspects can be seen. Pair 4 generally increases its relative efficiency during the last three years shown, while the efficiency of pair 2 decreases in this period. By comparing pair 1 and 4 it can be seen that there is a systematic seasonal variation, as pair 1 increases its efficiency towards the end of the year while pair 4 decreases its efficiency simultaneously.

TABLE 1
Comparison of old and new vessels

New vessels

Under the Faeroese management regime vessel owners are allowed to replace their vessels, but the fishing power of the new vessels should be similar to or lower than the old vessels. The BETA trawlers have a substantial age and the owner has prepared a renewal scheme for them. The company has made an agreement with the authorities where four old pairs (eight old trawlers) can be replaced by three new pairs (six new trawlers) of slightly larger hull size and engine power. In the discussion on how to compare the old and new vessels, it has been argued that the product of tonnage and engine power should be kept unchanged while changing from old to new vessels. Another argument is that it is the square root of the two that should be compared. Table 1 summarizes the details of the old and new vessels and the conversion calculations.

When the engine power is multiplied by tonnage the new vessels have 30 percent more efficiency whereas using the square root method the increase is only 14 percent.

Two new vessels have been in operation since the beginning of 2003. Table 2 summarizes the results from the new vessels compared with two old pairs in 2003.

The catches per day and per trip for the new vessels are 47-48 percent higher than for the old vessels. The new vessels had 41 percent more fishing days than the old vessels. The total yearly catch for the new pair is twice the catch of the old pairs.

With regards to fishing power the new vessels are superior to the old vessels in many respects. The bollard pull of the old vessels is approximately 12 tonnes whereas the new vessels have a bollard pull of 19 tonnes or 58 percent higher. The new vessels spend less time in harbour for repair. The holding rooms in the new vessels are arranged with bigger boxes that are much faster to discharge than on the older vessels. An ice machine on board saves time when preparing for a new trip. The new vessels can also carry out fishing in rougher weather than the older vessels.

TABLE 2
Results from old and new vessels in 2003

3.1.4 Discussion and conclusions

The efficiency of fishing operations may be seen from both an economic and a biological point of view (FTFB, 2004).

In most fisheries safe utilization of resources has relied on traditional fish stock assessment. In recent years increasing attention has also been paid to assessing the economic performance of fisheries. An important component in the determination of economic performance is a temporal change in technical efficiency (Pascoe and Robinson, 1996) and neglecting the efficiency change can lead to biased performance measures (Squires, 1994).

Fishing vessel efficiency increase based on technological progress can potentially result in higher catching capacity per unit and consequently result in higher fish mortality. In an effort-based (input-controlled) management system this can undermine the management regime as the pressure on the fish stock may increase to above an optimum target level.

Results from efficiency studies differ substantially between fleet segments and over time and trends are difficult to generalize or transfer between fisheries (FTFB, 2004). Applying a standard correction factor does not seem to be a valid option (Banks et al., 2002).

In the Faeroese management regime a target of 33 percent in numbers is set as an average yearly mortality for the main fish stocks. In the long term the fishing power of the total fleet can be adjusted according to this target. In the short term, however, it is of the utmost interest to know how an eventual efficiency increase will impact on mortality.

Technological advances do not necessarily lead to an expansion in production efficiency and an increased pressure on fish stocks but may rather lead to a reduction in production costs (FTFB, 2004). The conversion to pair trawling in the Faeroese fleet at the beginning of the 1980s was such an advancement.

In a mixed fishery it is difficult to calculate the creeping of the pressure on single fish stocks resulting from efficiency change in a particular vessel, since the fishing strategy does change according to the availability (and price) of the different fish species. To calculate an overall efficiency change over time it is probably necessary to include economics.

Efficiency increase based on improved catches can be obtained by either increasing the catch per hour or by increasing the hours fished. The latter seems to have been more present during the last decades in the Faeroese pair-trawler fleet.

Although the vessel owner and skippers claim that electronic aids have been beneficial to the success of fishing, this could not be verified by the present analysis. A positive effect from electronic aids may be masked by a time factor since it takes time to build up experience. Robins, Wang and Die (1998) found that fishers' experience with new electronic aids increased continuously after three years.

An analysis of the Dutch beam trawl fleet from the early 1980s and onwards suggests that the average level of technical efficiency did not increase substantially despite improvements in search and harvest technologies, whereas the introduction of newer, larger vessels had a positive effect on the average efficiency of the fleet (Pascoe, Andersen and De Wilde, 2001). This is in line with the present study, which indicates that continuous improvement over time is difficult to identify, whereas the introduction of new vessels results in a more pronounced incremental efficiency increase.

Although fishing power can be increased dramatically by investing in new vessels, no simple formula such as the product of tonnage and engine power can be used to predict the fishing power of a new replacement vessel compared with an old one.

Studies on fishing vessel efficiency increase might also help to advise vessel owners and operators to identify when and where to put new investments in order to improve profitability.

Summary

In the Faeroe Islands (situated in the Northeast Atlantic at 62°N, 7°W), marine resources are managed by effort quotas. Every year managers have to decide on the number of fishing days to be allocated to fishing vessels. In this yearly process the question arises as to whether the efficiency of a fishing vessel increases over time. The following text is an attempt to address the question of efficiency changes in a segment of the Faeroese fishing fleet.

From logbook data and additional information from the vessel owner and skippers examples of efficiency changes are demonstrated. The logbook data series includes 45 986 hauls in the period from 1985 to 2002 for eight identical trawlers 37.7 m long with 1 200 horsepower engines.

These vessels operated as single trawlers for a couple of years, but were then converted to pair trawlers. Fuel consumption decreased from more than 3 000 to 2 000 litres per day while the catch per vessel was maintained. An additional 15 percent saving was on gear expenses. This is an example of efficiency increase without exerting undue pressure on fish stocks.

When comparing the catch per hour of saithe and cod in relation to the respective stock size it is seen that the effort has shifted from saithe towards cod and then back again. The pairs that are most efficient on saithe are less efficient on cod and vice versa.

From the early 1990s there was a systematic increase in tow length for all vessels. For one pair the increase was substantial and maintained, while another pair has decreased the tow length to previous levels. The increase in tow length increases the hours fished per day, but the trade-off between tow length and fish quality presumably limits further increases.

According to skippers the tow speed has increased over the years from around 3 to 4 knots. This increases the swept area considerably.

According to the vessel owner the symmetry sensor on the trawl is the single electronic aid that has been most beneficial to fishing. However, when comparing pairs using the index on CPUE and the time for introducing the sensors, no effect could be found.

Since the beginning of 2003 one new pair of trawlers has replaced the old ones. The new vessels are of similar size and power (38 m, 1 305 HP) but the bollard pull has increased considerably (12 tonnes on old vessels, 19 tonnes on new vessels). Comparison of old vessels with new vessels shows a 48 percent increase in catch per day and a 41 percent increase in number of fishing days, which resulted in a 100 percent increase in total catch per vessel in 2003.

It is concluded that efficiency changes are difficult to access without using economic considerations, as effort changes towards species according to availability (and price). In the Faeroese case, the efficiency increase is more a result of an increase in hours fished (effort) rather than an increase in catch per hour (CPUE). There is no simple formula to predict the efficiency of new vessels compared with old ones.

REFERENCES

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FTFB. 2004. Report of the FAO/ICES Working Group on Fishing Technology and Fish Behaviour (WGFTFB), 20-23 April 2004, Gdynia, Poland. http://www.ices.dk/reports/ FTC/2004/WGFTFB04.pdf

Jákupsstovu, S.H., Olsen, D. & Zachariassen, K. 2001. Effects of seismic activities on the fisheries at the Faeroe Islands. Fiskirannsóknarstovan, Box 3051. Tórshavn, Faeroe Islands.

Pascoe, S., Andersen, J. & De Wilde, J.W. 2001. The impact of management regulation on the technical efficiency of vessels in the Dutch beam trawl fleet. European Rev. Agricultural Economics, 28: 187-206.

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3.2 A comparison of twin-rig and single-rig trawling in terms of relative fishing efficiency

D. Rihan

3.2.1 Background

Under the Irish Government's Whitefish Renewal Schemes of 1998 (Anon., 1998a) and 2001 (Anon., 2001) a number of new demersal vessels have entered the Irish fleet. These programmes are the most significant targeted investment in upgrading and modernizing in the history of Ireland and were brought to fruition despite the backdrop of wholesale cuts being proposed by the European Union (EU) under the multiannual guidance programme (MAGP VI) (Anon., 1998b). It was considered vital at that time to upgrade the Irish whitefish fleet in order to enhance competitiveness, safety and operational efficiency, since the average age of the fleet prior to the scheme was in excess of 30 years. To date a total of 44 new and modern second-hand vessels have been introduced to replace old and inefficient units.

The introduction of these vessels has, however, raised a number of questions in that while overall tonnage and horsepower have not increased above permitted EU levels, the overall fishing efficiency and the effort required to maintain viability have more than doubled. In particular, the use of twin rigs for species such as Nephrops and demersal species such as monkfish and megrim by these new vessels has attracted many critics, who say it is too effective and indeed a wasteful form of fishing. The method was first introduced in Ireland in the mid-1980s and was pioneered by the Irish Sea Fisheries Board (BIM) and Nephrops fishers in the Irish Sea, who saw the benefit of increasing the effective swept area of a trawl. It has proved so effective that many trawlers have converted to the method. including most of the new whitefish vessels. Its development has probably been one of the most significant advances in demersal trawl fisheries in the last 20 years and recently the use of three and even four nets has been tried in other countries, particularly in fisheries for deepwater shrimps (Pandaleus borealis); some Irish fishers are indeed looking closely at the triple rig for species such as Nephrops.

The "over-efficiency" arguments against the use of multirigs are well documented. In Ireland, as a result of increasing operating and gear costs as well as a chronic shortage of qualified crew, some of the larger operators who have been working twin rigs for mixed whitefish species have begun to investigate the possibility of returning to fishing with a single trawl to reduce costs. In order to ascertain whether this assumption is correct, BIM has carried out an assessment using two vessels as a case study, forming part of a much more detailed assessment of the success of the Whitefish Renewal Schemes.

The overall aim of this study was to ascertain whether, by returning to traditional single-rig trawling, an economic viability could be maintained, by offsetting a reduction in fishing efficiency with a reduction in operating costs. A secondary objective was to estimate the relative fishing efficiency through the use of gear monitoring systems and operational parameters of single as opposed to twin rigs.

3.2.2 Fleet métiers and case study

Table 1 summarizes the profile of the twin-rig sectors of the Irish fleet by length of vessels as taken from the EU Community Fishing Fleet Register (Anon., 2003a).

Available data (Costello, 2003) suggest that the Nephrops and Nephrops/whitefish "dual-purpose" twin riggers do not have a viability problem at present, and a return to single rigging for most of these vessels was not considered a viable option by the owners during discussions. Thus for this study the sector containing the 19 twin-rig whitefish vessels was considered, since these vessels are reportedly operating on a high gross earnings/high operating costs basis and in recent years on diminishing profits resulting from increased fuel costs and lower fish prices. The sector has grown in importance since the mid-1990s - the number of vessels has increased and the combined horsepower more than doubled. The 19 vessels currently involved are modern, around 20 -22 metres in length, 650 -850 HP/485 -635 kW and targeting monkfish and megrim off the south, southwest and west coasts of Ireland. They tend to work seven to ten day trips, fishing from the 100-metre depth contour out to depths of 600 to 700 metres and work up to 280 days per year. The gear used is typically either twin scraper trawls or double bosom trawls with long combination rope bridles and heavy doors and clump weights. Scraper trawls used tend to be small mesh with long, slow tapering wings, straight gable ends and light rubber footropes of plain rubber discs or small rockhoppers. These nets have a low headline height and consequently there is very little bycatch of roundfish. The double bosom trawl design was originally developed in Scotland primarily for catching Nephrops and is characterized by having a "tongue" section in the centre of an extended bosom section (Buchan, 2000). Weight is taken on this tongue section via bridles leading to the wing ends of the trawl. The tongue then divides the wide bosom into two smaller sections, giving increased ground coverage. This net design is now widely used by Irish vessels when targeting monkfish, although bycatch of other species tends to be lower than with more conventional trawl designs.

With the introduction of the new whitefish vessels, the size and weight of the gear used have increased dramatically since 2000. Previously vessels fished with 2 x 60 metre trawls, but they are now are working with 2 x 100 metre+ trawls. This has almost certainly been because the new vessels are more efficient and can tow much bigger, heavier gear and which fishers have equated with increased catch rates. In fact the use of larger gear has really only compensated in an overall reduction in catch rates for increased effort and operating costs.

TABLE 1
Breakdown of the Irish twin-rig fleet in 2003

Interestingly the economic viability of the Irish twin-rig fleet is mirrored by the continuing viability of the Scottish twin-rig whitefish fleet and similar questions have been raised. The vessels in this sector are very similar in size and operate in the North Sea and west of Scotland. They fish mainly in areas IVa and VI on seven to eight day trips. According to the Sea Fish Industry Authority (SFIA) 2001 economic survey of the UK fishing fleet (Martin and Watson, 2002), between 1998 and 2001 the average income for this fleet was reduced by almost £400 000, a decrease of 40 percent. During the period fuel costs were a major factor in the reduced profitability of the sector: they increased by 77 percent from 1998, and accounted for 59 percent compared with 29 percent in 1998 of total fishing costs. Conversely total vessel owner costs were found to have decreased by 23 percent since 1998 as a result of reduced expenditure on repairs and gear costs as margins became tighter.

The following case study describes the differences in fishing or catching efficiency, fuel consumption and overall profitability of reverting from twin to single rigging observed on two Irish vessels. These trawlers are typical examples of the craft in this métier and the owners would freely admit that since acquiring their new vessels they have increased the size of gear used from their previous crafts. With increasing costs they have questioned the logic of this and experimented with single rigs; the results from work with these vessels form the basis of the findings of the study.

The main specifications of these vessels (Anon., 2003b) and the fishing gear used are given below.

3.2.3 Findings

The specifications presented here were provided from Vessel A in 2003 and Vessel B in 2001. For the purpose of this study, the assessment of twin rigging against single rigging has been expressed as a function of fuel efficiency; and catch in terms of daily earnings and relative gear performance. Factors such as gear costs, crew and other operating parameters have also been considered. Costs of repayments, insurance, harbour dues, commission and other levies and dues have not been factored in since they remain largely constant whether the vessels fish with single- or twin-rig gear.

Table 2 summarizes the average earnings and fuel costs per day during the trial periods on the two vessels. This amounted to over 20 trips totalling 134 days on Vessel A from March to June and October to December 2003 and ten trips totalling 74 days on Vessel B over the period September to December 2001.

Average earnings/day

As catch rates fluctuated greatly from tow-to-tow with both gear types, it was decided to use daily earnings to compare the relative efficiencies of the two types. This is also the measure of performance used commonly by fishing skippers. As would be expected, both vessels found that there was a reduction in gross earnings per day using a single trawl compared with the twin rig. Both vessels had similar daily earnings when twin rigging ranging between €1 682 and €4 822 with an average of €3 281. When single trawling, daily earnings were between €1 739 and €5 694, with an average of €2 749. For Vessel A this equated with a reduction of 7 percent and for Vessel B it was in the order of 25 percent per day. Figures 1 and 2 show the difference in daily gross earnings by gear type over the number of trial trips on each vessel.

TABLE 2
Summary of operational parameters with twin- and single-rig gear types

Extrapolating from these figures using a 280-day fishing year would give a reduction in gross earnings over the year of around €62 000 for Vessel A and €236 000 for Vessel B. The difference in earnings between the two vessels is a result of a number of factors, including the fall in average fish prices for monkfish and megrim from 2001 to 2003 and also the different tactics employed by the vessels when reverting to the single rig. Vessel B tended to target similar grounds with a slightly different net design and a higher headline height to catch more hake and roundfish, while still catching monkfish and megrim. Vessel A targeted harder ground areas than could normally be worked with twin-rig gear, resulting in a wider catch composition comprising smaller volumes of high-value species, as well as monkfish and megrim.

Fuel consumption

Both vessels found by reverting to a single trawl that fuel consumption was reduced, as shown in Figures 3 and 4. In the case of Vessel A, the skipper reported a reduction from an average of 3 800 litres/day with the twin-rig gear to 3 000 litres/day with a single trawl, equating with a reduction in fuel consumption of approximately 21 percent. In monetary terms this equated with a 13 percent reduction in fuel costs per day. On Vessel B the difference was around 10 percent with a reduction from 3 100 litres/day to 2 800 litres/day, equating in monetary terms with a 9.5 percent reduction. It is interesting to note, however, that during 2001 fuel prices were around 19 cents/litre compared with 28 cents/litre in 2003. This shows that as fuel prices increase the savings from reduced fuel consumption become more pronounced.

Again, extrapolating from these figures for a 280-day fishing year would give a fuel saving over the year of approximately €39 760 for Vessel A and €14 840 for Vessel B.

Gear parameters

Door, wing end spread, headline height and towing speed information were recorded from Scanmar gear monitoring equipment fitted to both types of gear on board Vessel A during separate trips in 2003. These results are summarized in Table 3.

From the data gathered from both the single- and twin-rig gear an estimate was made of the relative fishing efficiency in terms of swept areas and volumes, defined as follows:

• Swept area net = wing end spread x speed

• Swept volume net = wing end spread x headline height

• Swept area doors = door spread x speed

• Mouth area = wing end spread x headline height

The results are summarized in Table 4.

As can be seen, the effective swept area of the trawls is increased with the twin rig by around 22 percent, with a corresponding reduction in swept door area of 23 percent when compared with the single rig. It was also found that the vessels were able to cover more ground when single rigging since they were able to tow one net at an average speed of 3 knots at the same engine RPM required to tow two nets at 2.5 knots, and hence covering a larger area per tow. It is also interesting to note that over the course of an average seven-day trip, Vessel A found that it was possible to tow for three hours per day longer with the single rig. This time was a result of the reduction in hauling time with one trawl as opposed to two nets. Over the course of a seven-day trip, the time thus gained is estimated at around 18 hours per trip, equivalent to 4.5 x 4 hour tows extra per trip.

These results should be treated with caution as they are based on trials over a short time and do not necessarily equate with optimum catch rates with either gears, although at these values the nets are fishing with similar bridle angles of 12-14º.

Other factors

According to the skippers interviewed, reverting to single rigging had a number of other potential benefits aside from the improved fuel efficiency and only slight differences in gear efficiency found.

TABLE 3
Recorded gear parameters for separate trips with single- and twin-rig gears on Vessel A*

*Based on data from one net.

TABLE 4
Estimates of relative fishing efficiency with single- and twin-rig gear

* Based on data from one net multiplied by 2.

The gear expenses associated with twin rigging have become increasingly prohibitive as reported by both skippers. Reverting to single rigging effectively means that a vessel does not need a clump weight, warp for the middle wire in a twin-rig system and only one set of bridles. At current prices this equates with a saving of around €16 000. Other gear expenses made up mainly of chandlery, e.g. shackles, hammerlocks and chain are also reduced, and during this study equated on average with between €500 and €1 000 per trip. Labour costs of mending nets ashore were also reduced by around €1 500 per month because of a reduced need to leave nets ashore to be repaired during trips. This is common practice for Irish twin-rig vessels since gear damage has increased as attempts have been made to open up new grounds and is now accepted as an added cost for these vessels. This represents a saving per year of approximately €30 000-36 000 in gear and repair costs. The skipper of Vessel A also reported that an additional benefit of the single rig was that he did not have to use the auto trawl system other than to shoot and haul the gear. This dramatically reduced not only wear and tear on the warps but also on the vessel hydraulics.

As discussed, single rigging also allows vessels to fish much harder ground, working along the edges of banks and on stony ground. This resulted in a different catch composition comprising small volumes of high-value species such as John Dory, lemon sole and red mullet, along with monkfish and megrim. With the single rigs, landings contained around 45-55 percent monkfish, in comparison with landings with the twin-rig gear, which was made up of 85-95 percent of monkfish. The overreliance on one species for the majority of a vessel's earnings is a cause of concern for many of the skippers in the twin-rig sector and small catches of high-value species are seen as one way to supplement earnings. Should monkfish quotas in particular come under further pressure or, as has been the case in the last two years, prices for monkfish and other "Spanish" species drop further, the economic viability of Irish twin-rig vessels is further in question.

Vessel B also found crew numbers could be reduced by at least one man with the single-rig gear, because of the lesser time spent hauling and shooting and a reduction in gear damage. Working with one less crew member would represent a saving of around €25 000 per year for Vessel B. Vessel A, however, has maintained the same crew size as the vessel tended to work the crew harder and incurred significant gear damage, although with one net the crew can cope with this level of damage without downtime at sea. Whether single rigging ultimately will allow a reduction in crew numbers is therefore based very much on the fishing tactics employed.

3.2.4 Conclusions

The findings suggest that, for this sector of the Irish fleet, a return to single-rig trawling has some obvious advantages, particularly in terms of fuel and other cost savings. However, there will be a corresponding loss of earnings which, from the results of these two vessels, averages out at 16 percent.

Extrapolating from the fuel savings and the indicative reduction in gear and crew costs showed the reduction in gross earnings to be almost negated on Vessel A. This vessel has remained single trawling. Results from Vessel B showed savings not as high compared with the reduction in earnings, largely because of lower fuel costs and higher prices for monkfish at the time of the first part of the study. The owner of this vessel was less convinced about the benefits of single trawling at the time and the vessel reverted back to twin rigging at the beginning of 2002. Subsequently it switched to single trawling during the summer months in 2002 and 2003 when monkfish were generally less prolific on the grounds and it intended to do the same in 2004, targeting megrim and hake that currently have less quota restraints.

The differences in earnings also reflect the different strategies adopted by the vessels when reverting to single-rig trawling, and in this respect there is no doubt that when monkfish are the main target species the twin rig has a significant advantage over the single rig. The overreliance on this species, however, raises serious questions and it is fully accepted by all the operators in the twin-rig sector that there is a need to diversify to other species.

In terms of relative fishing efficiency twin-rig gear has an advantage in swept net area but again this is largely counteracted by the fact that much longer bridles can be worked with a single net, giving a larger swept door area. Towing one net also has the added advantage of increasing the effective fishing time by up to three hours per day, equivalent to four complete tows a trip.

This study was not designed to be a full economic analysis of the profitability of twin rigging compared with single rigging for the entire sector, but more as an indication to the skippers involved in this sector to examine their current operations closely and assess whether there is a need to consider other options for their vessels, including returning for part or all of the time to single trawling. In this respect the study has raised a number of relevant points.

REFERENCES

Anon. 1998a, 2001. Fishing fleet development measure. Towards competitiveness, safety and operational efficiency in the whitefish fleet. Department of the Marine and Natural Resources and Bord Iascaigh Mhara Programme. 12 pp.

Anon. 1998b. Commission Decision of 16 December 1997 approving the multiannual guidance programme for the fishing fleet of Ireland for the period from 1 January 1997 to 31 December 2001. Official Journal of the European Communities, OJ L39 (12 February 1998): 41-46.

Anon. 2003a. Irish Fleet Register contained in EU Community Fishing Fleet Register. Regulation on Fleet Register (EC) No. 26/2004. 30 December 2003.

Anon. 2003b. Fishing vessels of Britain and Ireland 2003, pp. 267-297. Fishing News Publication. Agra Europe (London) Ltd.

Buchan, M. 2000. Groundfish trawling 2000 - Jackson trawl perspective. Paper presented at Fishing Gear Systems 2000, 27-29 March 2000. 12 pp.

Costello, L. 2003. 2003 Pilot economic survey. Irish Sea Fisheries Board (BIM) and the Economic and Social Research Institute (ESRI) Final Report.

Martin, A. & Watson, J. 2002. 2001 economic survey of the UK fishing fleet. Sea Fish Industry Authority Report, June 2002. 277 pp.

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SUCHITRA M. UPARE

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