5.1 Fishing for orange gold
There are relatively few commercially exploited fish with natural mortality rates as low as that as the orange roughy (pers. comm. Merrett 1997; Angel 1997). Whilst the orange roughy (Hoplostethus Atlanticus) has a worldwide distribution, it has only up until now been fished commercially off New Zealand, Australia and in the north-eastern Atlantic Ocean. In Namibia, boats are now beginning to target for the first time orange roughy off the coast of South Africa (Robertson 1991; FNI 1996; ICES 1995a).
In all these fisheries, the vessels have tended to target the orange roughy when they come together to spawn on steep slopes or on top of seamounts. The fishing trawls can easily swoop down on the males and females, catching several generations of fish, making very large hauls within a matter of a few minutes. Boat owners in New Zealand were able to pay off multi-million dollar bank loana within just a few years.
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Even reports in the international fishing press have warned that the orange roughy “could easily become extinct if over-exploited as it matures at between 25 and 30 years” (FNI 1996). All around the world the roughy has been exploited because of its high market value, and attempts to manage the fisheries have ended up in a biological disaster.
New Zealand
Prior to 1975, orange roughy was known only from a few museum specimens. In 1979, a commercial deepwater fishery developed off the east coast of the South Island in New Zealand. The Chatham Rise fishery for orange roughy was a classic boom-bust fishery. The early years were boom years with a regulation Total Allowable Catch (TAC) being exceeded but the latter years have been bust years with the TAC not reached despite a significant increase in fishing effort (Taylor and Baird 1983).
The New Zealand fishery targeted large spawning aggregations of orange roughy which occur in very localised areas, such as the seamount at Chatham Rise. This schooling behaviour makes them vulnerable to exploitation (Clark 1990).
Catch rates at the spawning sites remained high as long as there were fish spawning, but dropped dramatically thereafter. In spite of the significant depletion of known spawning aggregations, overall catches have continued to increase (FAO 1993), but this obscures some real problems with the fishery. New fishing grounds were continually being found to replace areas where catch rates began to decline. Some fishermen used inadequate nets, which burst when the trawl filled to a certain level. The fish lost were likely to be so badly crushed that they would die (Gordon 1993a; FAO 1993). The amount of fish killed was much higher than the quantities landed and the reported catch figures were probably mis-judged by an estimated 20-30 per cent (Clark 1990). This meant that an additional 20-30 tonnes of roughy were killed and lost for every 100 tonnes landed (NZ Fisherman 1994a).
When fisheries scientists recommended an 84 per cent reduction in catch, the Fisheries Minister chose not to reduce the catch for the next two years. For the 1989-90 season, the Minister ruled that the quota be lowered by only 20 per cent, despite being told that there was a 45 per cent risk that the orange roughy fishery would collapse within five years (Norse 1993). The Ministry of Agriculture and Fisheries (MAF) also had to buy back the quota at inflated prices. The fishing industry knew they had MAF “over a barrel” and took full advantage of that. To anyone but the most naive these moves made the position of the fishing industry clear; they were not interested in taking responsibility for the damage they were doing to the resource, but were interested in their short-term profits (NZ Fisherman 1994b). In 1991-92 MAF spent about NZ$ 3 million of public money studying the orange roughy fishery, about a third of its total research budget. The fishing industry have spent considerable time and money trying to get MAF to allow them to catch still more fish. They have hired “overseas experts” to argue that the fishery is actually in a better state than is estimated. The corporate mentality still seems obsessed with short-term profits (NZ Fisherman 1994b).
There have been several other roughy fisheries discovered since the Chatham Rise was developed, but none of them match the size of the Chatham resource. Many of these smaller grounds suffered the same fate (NZ Fisherman 1994a). The rate of depletion of some of these spawning aggregations has been very high (Annala 1993), with some of the early concentrations now decreased to 10 per cent of their virgin biomass (Kailola et al.1993; FAO 1993).
Australia
An equally disastrous situation has taken place in the Australian orange roughy fisheries. It was recently estimated that the St Helens concentration of orange roughy, off eastern Tasmania, has also been reduced to about 10 per cent of the virgin biomass. Catches were once 50,000 tonnes in the boom days but began declining in 1991. In 1997, the allocated TAC for this fishery was set at 2,000 tonnes. Some think that this catch will now never be met. It is now becoming uneconomical to target orange roughy, and so market forces rather than strong management will force the eventual closure of the fishery (AFMA 1997).
The high catch rates obtained by individual boats fishing for orange roughy in New Zealand and Australia in the earlier stages of the fishery were an incentive to increase fishing effort every year (FAO 1993). In Australia, lots of people made large amounts of money during the boom period. However, lots of people also went broke after the catches declined. A paper entitled “The boom and bust of orange gold: the history of the orange roughy fishery in Tasmania.” sums up the disaster (AFMA 1997).
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Atlantic Frontier
In the Atlantic Ocean, the orange roughy is distributed from the south of Iceland and along the continental slope of Europe and northwest Africa. Orange roughy seem to prefer the relatively warmer waters of the deep Atlantic slope. The undersea ridge which runs between Shetland and Faroes (Wyville Thompson Ridge) at a depth of about 500 metres appears to act as a major barrier to its occurrence north and west of the Shetlands (Gordon 1993a).
There can be little doubt that it was the landings of orange roughy into the port of Lochinver by French trawlers in 1992 that stimulated the current interest in deepwater fish in Scotland. Initially there was a reluctance to believe that a species which is the basis of an important fishery in the deepwaters around New Zealand could also occur in Scottish waters. However the existence of this species was known for many years (Gordon 1994a).
The orange roughy has had a particularly unfortunate history in terms of its identification. In the early 1970s, the Ministry of Agriculture, Fisheries and Food (MAFF) Fisheries Laboratory in Lowestoft and the White Fish Authority (now Sea Fish Industry Authority, SFIA) carried out extensive surveys on the continental slope to the west of the British Isles, down to a depth of about 1,200 metres. Moderate catches of orange roughy were made but they were incorrectly identified as Gephyroberyx darwini, for which there is no common name. The survey team decided to name it the Director’s Fish (Gordon 1993a).
In 1979 a report appeared in the German fishing press of large catches (20 tonnes a haul) of orange roughy from the northern slopes of the Rockall Trough, the Rosemary Bank or Seamount, by trawlers targeting blue ling (Gordon 1993a,b).
In 1991, French trawlers also targeting blue ling in Scottish waters suddenly found large catches of orange roughy in their nets. They landed some 4,952 tonnes that year. In 1992 they caught almost as much - 4,121 tonnes. In 1993, a year which saw the collapse of commercial orange roughy fishery, landings were down to 2,100 tonnes (France-Eco-Peche 1994; ICES 1995a). These figures tend to suggest that the Atlantic Frontier population of orange roughy is already history, or at least for one sub-area of its population. The trawlers from Boulogne appear to have wiped out the existing orange roughy adult population within three years of targeting this deep-sea fish.
One French fishermen involved in the fishery remarked: “The orange roughy is not worth the effort it takes to catch it. Once you have had one or two good hauls, it is time to move on and look elsewhere.” (Leduc 1994). It is no wonder why some fisheries scientists refer to deep-sea fishing as more like mining.
Now an estimated five or six vessels from Lorient are targeting the Scottish waters, landing only small quantities of orange roughy. It is not clear whether they are fishing directly for roughy on spawning aggregations or taking them as bycatch in other deepwater fisheries as they are also landing deepwater sharks and the greater forkbeard. They may simply be catching recruiting year-classes of orange roughy (pers. comm. French fishermen, Lochinver, 1997). Although the exact location of the French fishery is shrouded in secrecy, it seems reasonable to speculate that they are exploiting spawning populations on steep slopes (Gordon 1993a).
5.2 Other vulnerable species
Of the deepwater species which are commercially exploited or killed in significant quantities in the north-east Atlantic and/or the Atlantic Frontier, the following examples are detailed based on what has already been documented about these species. The impact on other non-target species which suffer fishing mortality may be more severe, as some species are considered rare or a smaller part of the biomass in the Atlantic Frontier region. No data or documentation is available on these species, nor is likely to become available.
Smoothheads (Alepocephalidae spp.)
It was the discovery of large stocks of smoothheads to the west of the British Isles which largely prompted the investigation into the potential usage of deepwater species of fish. The smoothhead grows to about a metre long, and is thought to be related to the herring and salmon families. Too many factors make the smoothhead an unlikely proposition for commercial exploitation, especially as it has extremely watery flesh (MAFF 1974). The smoothheads have no air or oil-filled swimbladder and have managed to evolve natural buoyancy by having flesh with a very high water content (Gordon and Swan 1997b; pers. comm. Nigel Merrett 1997).
At least 14 different species of smoothheads are found in the deepwater to the west of the British Isles, but most inhabit the deeper water below 1,500 metres. Most of the deeper-living smoothheads can be quite rare or are unrecorded in the Rockall Trough (Gordon and Swan 1997b).
The Baird’s smoothhead (Alepocephalus Bairdii) is a slope dwelling species and has a depth range of between 700 and 1,800 metres (Gordon 1996b). There is no information on the age composition and growth rates of the Baird’s smoothhead (Gordon and Swan 1997b). They can make up around 50 per cent of catches on the continental slope to the west of Scotland at depths of 1,000 metres, and up to 61 per cent in depths of 1,200 metres or more (Gordon 1996b). Even as far north as the Faroe Islands, Russian surveys showed that up to about 25 per cent of the weight of trawl catches consisted of smoothheads. Fishermen consider the smoothheads as a “nuisance fish” (Gordon and Swan 1997b). From these depths there will be nil survival of catches returned to the sea as discards, whether of the smoothhead or any other deepwater species.
Argentine (Argentina silus)
In 1990, a crash in catches of argentines was experienced in an Irish directed deepwater fishery in an area west of the Hebrides. Landings were 5,454 tonnes in 1988, followed by 6,103 tonnes in 1989. In 1990 the same fishing effort was employed as 1989, but landing crashed to 585 tonnes (ICES 1995a). The Irish Fisheries Research Centre, summarised the crash possibly due to the “over-exploitation of a spawning stock, as well as a change in the distribution of the fish towards less fishable grounds.” (Kelly 1994).
Ageing of samples taken from the Irish catches showed that 40 per cent of the fish were greater than 20 years old (Molloy and Mahon 1991). Also that there were no immature fish in the catches, which were mainly comprised of spawning adults (ICES 1995a).
Redfish (Sebastes spp.)
There are three species of red fish (Sebastes), sometimes called Norway haddock. Both fishermen and some scientists have difficulty in identifying the difference between the three species of deep sea redfish. There has been considerable controversy over the separate identity of Sebastes marinus and Sebastes mentella. They are not separated into species in ICES catch statistics or assessments. Collectively they are simply known as redfish (Gordon 1993a).
In the Irminger Sea, the existence of the deepwater redfish (Sebastes mentella) was discovered during an Icelandic survey in 1991 on the oceanic redfish, Sebastes marinus. The fleet fishing targetting oceanic redfish in the uppermost 400 metres has already started venturing into deeper waters around 600-700 metres for the deepwater redfish, which is of high commercial value, and has obtained good catches (ICES 1995a).
Redfish are quota-regulated in the Icelandic and Faroese slope fishery (ICES 1995a). To the west of the British Isles, the redfish are not quota regulated. They occur in the Rockall Trough but apparently not in large enough numbers to encourage fishermen to directly target them (Gordon 1993a). It is known that redfish take a long time to grow to adulthood; one study suggested that the Atlantic redfish may live up to 75 years (FNI March 1997; Campana et al. 1990). However, Scottish boats are now landing both Sebastes mentella and Sebastes viviparus caught in a general ‘mixed’ fishery into Lochinver (Copius 1997; UNESCO 1989).
Roundnose grenadier (Coryphaenoides rupestris)
The roundnose grenadier (rock grenadier) is a slope dwelling species and has been recorded in research surveys to the west of the British Isles at depths between 450 and 1,850 metres (Gordon 1996b; Gordon and Swan 1996). It is a distant relative of the cod family found in the shallower waters around the continental shelves of the Atlantic (Gordon and Swan 1996). The French are thought to sell it to schools as a cheap alternative to cod.
At 700 to 900 metres the roundnose grenadier is an important species. It is a widely distributed in the North Atlantic and is commercially fished off Canada, Greenland, Iceland and Scotland (Gordon 1992).
Scientists still know very little about the populations of grenadier and its spawning migrations (Gordon and Hunter 1994c). It is known that the roundnose grenadier is a long lived species, although there are problems with validating the age of this species, most investigations suggest ages of up to 40 years. However, studies on specimens from the Norwegian Deeps (Bergstad 1990) indicate ages up to 70 years and studies in deepwater of the Skaggerak off Denmark suggest ages of 50 to 60 years are not uncommon. The females were thought only to reach maturity at around 10 to 15 years (Gordon and Swan 1996). If catches are composed mainly of old, slow-growing fish then it is doubtful whether the stocks could sustain a prolonged fishery without being reduced to the recruiting year class as is the case of many North Sea demersal species (Gordon 1992).
Trawling presents a serious problem for this grenadier. Generally in deepwater fish, the juveniles live at shallower depths than the adults but in the case of the roundnose grenadier in the Rockall Trough, the juveniles and the mature adults occupy shallower depths than the sub-adults (Gordon 1994a). The main fishery is likely to be for the adults at the shallower depths and because grenadier lacks a tail fin and instead the body tapers gradually to a fine point. This could result in damage to the juveniles in escaping from the trawl as invisible discards and hence they could suffer a high mortality (Gordon 1994a; Gordon 1994b).
Blue ling (Molva Dypterygia)
The blue ling is a slope dwelling species (Gordon 1996a). In the waters to the west of the British Isles, blue ling have been reported from depths between 300 and 1,450 metres but it is most abundant between 700 and 1,000 metres. The fishery for blue ling is long established in the North-eastern Atlantic and largely takes place on aggregations during the spawning season. Blue ling spawns in the Rockall Trough from about February to June. There is some evidence that they spawn earlier on the slopes of the northern banks, such as George Bligh and Lousy, than on the Hebridean slopes (Gordon and Swan 1997a).
Landings increased during the late 1970s, reached a peak in the early 1980s and since then have gradually declined, supposedly as a result of a series of poor spawnings. The increase in landings in the 1980s was mainly the result of targeting new aggregations of blue ling. In the area west of Scotland, France has landed the largest quantities of blue ling but Germany had significant catches in the 1980s as a result of targeting pre-spawning and spawning populations in the northern parts of the Rockall Trough during February and March (Gordon 1992b; Gordon and Swan 1997a).
In the Rockall area, the German fishery was important in the early 1980s but French and Faroese fishermen have dominated the fishery in recent years. The Norwegian and part of the Faroese landings are taken as bycatch in their longline fishery for ling and tusk. The French deepwater fishery targets different populations of blue ling, at different depths and different times of the year. It has therefore been difficult to detect changes in the size of the fished populations of blue ling. Because of the inadequacy of this data, the state of the populations is unknown and as a consequence no management exists for this fishery (Gordon and Swan 1997a).
It appears that the youngest fish caught are aged about six to eight years, the age at which the females tend to become sexually mature. Most blue ling are caught between eight and 16, the oldest are about 27 years. Juveniles are very rarely caught in commercial trawls, fine mesh research trawls and longlines (Gordon and Swan 1997a).
Black scabbard (Aphanopus carbo)
The black scabbard fish is a slope dwelling species with a depth range from 600 to 1,000 metres (Gordon 1996b). In the waters to the west of the British Isles the black scabbard fish is caught by bottom trawls. All are about one metre long and none of them are sexually mature. The larger specimens are sexually mature fish are caught off Madeira. The lack of basic life-history information makes any assessment of the potential for a fishery very difficult (Gordon 1994a).
Monkfish (Lophius spp.)
Two species of anglerfish are being targeted off the west of the British Isles, Lophius piscatorius and Lophius budegassa. Collectively they are landed and marketed as ‘monkfish tails’ (ICES 1995c). The tails are cut away from the main bulk of the body, which is thrown away. A large portion of the weight of these monkfish is discarded.
The present big interest by Scottish boats in the zone from 200-800 metres centres on these deepwater fish, which have a high market value. The distribution of Lophius piscatorius west of the British Isles is known to be distributed as far down as 1,200 metres. There is no currently no minimum landing size for both of these monkfish, which are being landed from around 30 centimetres in length to around 120 centimetres in length (Gordon and Hunter 1994a; Scottish Fish Markets 1997; Fishing News 1997a).
The majority of fish being landed in Lochinver, Kinlochbervie and Scabster are currently range from a medium to smaller size. Although little is known about the biology of these two species of angler fish, it is likely that the smaller fish are juveniles (Scottish Fish Markets 1997). The rapid decline in catches of older fish may be indicative of heavy exploitation on these populations and/or a shift in exploitation pattern (ICES 1995c), i.e. to greater depths where the juveniles might live. The consequences of heavy exploitation on these monkfish, and changes in fishing areas, will undoubtedly put these stocks at great risk.
This current fishery probably requires considerable trawling effort to achieve viable catches and, as a consequence, results in the discarding of other deepwater species and even some traditional species that are managed by quota (Gordon and Hunter 1994a).
Deepwater sharks
There are thirty families of sharks worldwide, eleven of which are represented in the waters to the west of the British Isles. In the shallower waters of the continental shelf there is only one species, the spurdog, also known as ‘rock salmon’. In the deepwater there are nine species which are commonly caught by deepwater trawling and form a large part of the total catch (Gordon and Hunter 1994a; Bridger 1978). The 1970s MAFF survey positively identified sixteen species of sharks and spurdog. Several other unknown species were caught and had to be sent to the British Museum for identification (Bridger 1978).
Unlike the smoothhead, which can be avoided by trawling at depths less than 1,100 metres, sharks cannot be avoided (Bridger 1978). Therefore a large number are discarded. In the French trawl fishery to the west of the British Isles many of the smaller deepwater sharks are discarded, sometimes after removing the liver for its squalene oil, used in the cosmetic industry. In recent years Spanish fishermen have begun to target deepwater sharks, including the Portuguese dogfish (Gordon and Swan 1997c).
There is much to be learnt about the reproductive biology of the deepwater sharks, but some Japanese research suggests that the cycle from fertilisation of the egg to birth may take two years. By the time they adult shed their young, a process known as “pupping”, they are fully developed sharks of about 30 centimetres. The portugese dogfish can produce 13-16 young in a litter (Gordon and Swan 1997c) which are of a size which can easily be caught in a trawl fishery. These ‘pups’ will most probably be discarded if caught.
Although some of the deepwater sharks are quite distinctive, it is likely that fishermen will not be able to identify them, simply landing them as deepwater sharks, ‘darkie Charlies’, or black sharks, etc. The two large sharks, Centrophorus squamosus and Cetroscymnus coleolepis, have both been found on the French market at Lorient. However, it appears that the Portuguese dogfish (Centroscymnus coelolepis) is the species which is most in demand (Gordon and Hunter 1994a). The Portuguese dogfish is one of the larger sharks on the slope to the west of the British Isles. It has been caught by surveys at depths between 650 and 1,750 metres, with peak abundance and biomass at about 1,000 metres (Gordon and Swan 1997c).