et al Tables 22 & 23. (NMFS special data run)

The total amount of fish of the above species landed and used amounted to over 1.4 million tonnes. The reason the above were discarded are various. There is for instance a ban on landing of halibut in the region so that all halibut from what ever gear is discarded. In pollock trawl fisheries small pollock make up 60 -70 % of the discards because they are either legally undersize or not commercially worth landing. Similarly in the Atka mackerel fishery 60 % of the discards are of Atka mackerel. However small cod in the cod trawl fishery make up less than 10% of the discards with other species such as pollock, rocksole, arrowtooth flounder and Atka mackerel making up the rest. In addition to these extensive observer programmes the North Pacific Fishery Management Council have instituted controls since 1986 on the amount of bycatch that can be taken in the ground fish fleet. (Smith 1993) Recognising that groundfish fisheries not only take small specimens of their own targets but also specimens of target species of other fisheries such as halibut, crab, herring and salmon these species were given a Prohibited Species Catch (PSC) limit to target fisheries for bycatch species.

8.2 North West Atlantic (Canada)

The information in Table 2 below taken from a paper on discards in the fisheries of Canada in the Atlantic Ocean (Duthie 1996) gives the amount of all species discarded by each type of gear and the target.

Canada now has a regulatory requirement in the groundfish fishery that all catches and bycatches are landed. This is considered reasonably effective, particularly on larger vessels which are required to have 100% observer coverage. This implies of course that there are now no discards at all in these fisheries. This may not in fact be true but as with the banning of discards in other countries it makes the industry move towards the elimination of unwanted catch voluntarily. The use of separator grates and other bycatch reduction measures has been regulated for alongside the discard ban.

Table 2 - 1994 Estimated discards from the Atlantic Canada fisheries

8.3 North East Atlantic and North Sea

The major fisheries of the North Sea and the Celtic Sea are governed in part under the Common Fisheries Policy (CFP) of the European Union (EU). The CFP has provisions to enable the introduction of measures in five areas to control and regulate fisheries in EU waters. These include total allowable catches (TAC) and quotas, technical measures, structural policy, marketing policy and access to third countries waters.

The implementation of restrictive TAC designed for conservation of stocks simply seems to exacerbate the problem of illegal landings and wasteful discarding in the North Sea cod fishery according to Salz P (Ed) (1996).

The flatfish fishery of the north sea has TACs for plaice and sole but not for the other flat fish species such as witch, turbot, brill, megrim, dab, and flounder although there are minimum landing sizes for these species. There are also mesh size regulations. The general minimum mesh size for demersal trawling in the North Sea is 100 mm, however there are exceptions for certain fisheries. When fishing for sole, for instance south of 55^oN a minimum mesh size of 80 mm is allowed as long as the catch is at least 5% sole and no more than 10% of the catch is composed of cod, haddock or saithe. The minimum landing size for plaice is larger than that for sole and in using the 80 mm mesh undersize plaice are caught. This situation leads to substantial discards of undersized plaice by the fishermen to avoid landing of undersized fish and to ensure that the proportion conform with the regulations.

In the North Sea documentation of catches of haddock and whiting over recent years through at sea sampling have allowed an assessment to be made of the discarding of the target species of these two species. This data indicates that significant quantities of both species are discarded. See Table 3 below.

Table 3 - Annual weight of haddock and whiting in human consumption landings, discards, and bycatch of the industrial fishery

North Sea Haddock

North Sea Whiting

More recently a paper by Smith of FAO (Smith 1996) attempted to estimate discards on a gear by gear basis for the major types of fishery in the North Sea and N E Atlantic. The results of the analysis made by Smith are given in Table 4.

Table 4 - Estimates of discards in the North Sea and North Atlantic

A major problem with the fisheries of the North Sea is that there are a number of major species of gadoid fish all able to be caught with similar gear but with differing growth patterns and optimal sizes for harvesting but with overlapping areas of abundance e.g. cod, haddock, saithe and whiting. The fact that the various species mature at different sizes requires that the permitted catch sizes for the different species should be different and therefore the mesh sizes of the cod ends required to catch them are correspondingly different. This means that a suitable mesh size to catch haddock for instance will catch cod (which matures at a larger size) which are under size.

It is estimated that the amount, in terms of number of individuals, of haddock discarded in the North Sea may exceed the number landed and similarly the number of hake discarded in the Bay of Biscay/Celtic Sea may exceed the number landed. (OECD 1997b)

The emphasis in the work cited above is on the discarding of specimens of main commercial species caught in the North Sea. A study of discards of fish with very little or no current commercial value has been undertaken on behalf of the Commission of the European Community (Jensen et al 1994). This study concentrated on the discards in the Scottish and Danish fleets operating in the North Sea and specifically excluded discards of main commercial species such as cod, haddock, plaice, whiting, saithe, sole, herring, sprat and mackerel. The main species which were found to be discarded were as in Table 5 below. In addition significant discards were found of Norway pout, lesser spotted dogfish, horse mackerel, witch and cuckoo ray. Of the species studied the Danish fleet was estimated to discard 4,237 tons per year, the Scottish Nephrops fleet 2,820 tons per year and the rest of the Scottish fleet 12,757 tons/year.

Table 5 - The five highest discards of non commercial species in the Danish and Scottish North Sea fleet

8.4 South East Atlantic

In the Southern Atlantic off the Angolan, Namibian and South African coasts Japp (1996) estimated the amounts of discards for various species as in Table 6 below. Japp reports small quantities of other discards caught by other types of gear such as some snoek from the handline fishery and hake, shark and kingklip from the long line fisheries of the area. As can be seen from Table 6 however there appear to be substantial quantities of discards from trawl fisheries of various types. This is one of the few publications where discard estimates of particular species are made against particular types of fishing gear, rather than a blanket figure being given for all species discarded against a gear or of a figure for one species being discarded over a number of gears.

Table 6 - Discards in the South East Atlantic

Japp reports that in Natal province of South Africa in spite of increased utilisation of bycatch and better selectivity in trawling there are still regular reports of dumping particularly when markets require specific sizes of fish.

8.5 Japan

Estimations of discards in some Japanese fisheries are given by Matsuoka (1996) who taking the best available evidence tries to assess the quantities of the various species discarded in the many and various fisheries in Japan. He concludes that the major discards problems are associated with the small trawl and boat seine fisheries in coastal waters of Japan. There are also major discards of fish associated with the distant water long line tuna fleet. Quantified discards of particular species are given as in Table 7.

Table 7 - Partial estimates of discards of some major species in Japan (1994)

However the quantification of the amount of discards is less certain in most cases and Matsuoka is only able in most instances to indicate in more general terms that fish of particular groups are discarded during various types in fishing operation. This information is summarised in the Table 8 below.

Table 8 - Summary of major discards from the various fishery types in Japan

8.6 Falkland/Malvinas Islands

The fishery around the Falkland/Malvinas Islands in the South West Atlantic which started commercially in 1987 has been regulated and controlled on the basis of real time commercial and scientific data since soon after it’s inception. (Nolan and Yau 1996). This has involved collection of data from commercial logbooks, scientific onboard observation and research cruise information. The entering of information on discards into logbooks is mandatory under the licences issued for fishing by the Falkland Islands Government, however it has been found that the information entered into the logbooks is often incomplete and unreliable. The log book records have been compared with those recorded by onboard observers and show that vessels without observers on board reported only 24% of the total bycatch recorded by observers over the same period.

The long line fishery for Patagonian toothfish (Dissostichus eleginoides) catches a high proportion by weight of the target species which is discarded because it suffers from what is known as "jellied meat". Nolan and Yau report that over 56% by weight of the toothfish are discarded because of this condition but that this represents less than 14% of the number of fish caught. This suggests that the condition is associated with larger and older fish and that it may become less of a problem as the larger fish become fished out in this relatively young fishery. The jellied meat condition is associated with myxosporidean protozoan parasites in other species of fish although as far as is known no specific identification of the cause in Dissostichus eleginoides has been made.

In the pelagic trawl fishery for southern blue whiting (Micromesistius australis australis) catches of non-target fish are rare and it is reckoned that less than 0.4% of the catch is generally discarded. However the southern blue whiting itself is often heavily infested with Kudua alliaria (a myxosporidean protozoan parasite) and these fish along with those too small for processing will make up the bulk of discards.

Table 9 summarises the major species in the discards by type of fishery as reported by Nolan and Yau. Overall the most commonly reported species in the bycatch/discards are notothen, blue whiting, and hoki. Other species which are incidentally caught but which are not recorded as discards because they are probably consumed on board the vessels include, kingclip, common and Patagonian hake. The discarding of undersized specimens of commercial species are also only occasionally recorded in log books.

Table 9 - Major discard species in Falkland/Malvinas Islands fisheries

8.7 Western Pacific Ocean tuna fishery

The western and central Pacific Ocean represents the highest concentration of tuna fishing in the world. The statistical area covered by the South Pacific Commission produced an estimated catch of 948,863 tons in 1995. The major species of tuna caught are dominated by skipjack (70%), yellowfin (23%), bigeye (4%) and albacore (3%). The majority of the catch is harvested using purse seines (80%), longline harvesting 12% and pole and line just 8%. There are also small commercial fisheries utilising handlines and trolls for tuna. Bailey et al (1996) review the literature holdings of the South Pacific Commission concerning bycatch and discards in the tuna fisheries and it from this document that the information that follows is extracted.

8.7.1 Purse seines

Purse seine catches can be divided into a number of categories dependent on whether the set was made on a school of fish associated with an object or not. It appears that this association has an affect on the amount of non-tuna (bycatch) species caught at the same time.

Logbook data suggests that 50% of purse seine catches are made on schools not associated with floating objects whereas others are associated with floating logs (34%), man-made fish aggregating devices - FADs (5%) and a small number (1%) with animals. The non-associated school sets tend to produce a lower incidence of non-target species in terms of numbers, weight and the variety of species than those associated with floating objects. It is suggested that un-associated sets produce between 0.35 and 0.77% bycatch whereas associated sets produce 3.0 to 7.3% bycatch. The mix of species are also different depending on the type of set.

Un-associated sets commonly produce ocean anchovy (Stolephorus punctifer) bycatch with smaller numbers of shark, scombrids, billfish and other species.

Whereas associated schools have a higher incidence of bycatch and a larger number of species as shown in Table 10

Table 10 - Species found as bycatch in purse seine catches associated with floating objects

With schools associated with logs the purse seines can harvest around 1 tonne of non-target fish per set (range 0.5 to 5.0 tonnes) of which a large portion may be discarded. It has been found, however, that rainbow runner and trigger fish may survive the discarding process and thus are generally released alive. Some mahimahi and wahoo may be retained for eating by crew. Generally, schools attracted to FADs will have the same species composition as the log sets but possibly in larger quantities. Sets on schools alone can include sharks such as silky and oceanic white tip and marlins (blue and black).

8. 7 .2 Long lines

Non-tuna bycatch in tuna longlines can include billfish, blue shark, oceanic white tip shark, Carcharinus spp and turtles. However, these species are thought to have high survival rates and therefore may not be a particular problem. When skipjack are caught these may be discarded. There may be irregular and unpredictable discards of target tuna species because they are too small or damaged.

8.7.3 Pole and line

Pole and line fisheries can produce bycatch of kawakawa (little tuna), frigate mackerel, mahimahi and rainbow runner. However the fishery uses live bait so if bycatch gets too high the vessel will stop fishing or move to other grounds to save wasting the bait. With the use of barbless hooks and flick off practices the survival rates for accidentally caught fish are thought to be high. Unsalable fish may also be taken home by the crew and in Fiji has been given to coastal communities to compensate for bait fishing access. (FAO 1997).

8.7.4 Trolling

When trolling the main targets are juvenile albacore 90 cm long. The bycatch may include sharks, scombrids, billfish, other tunas and skipjack most of which is discarded. Yellowfin may be retained if caught whilst heading for port. Some of the bycatch may be kept for crew consumption. Albacore may be lost during hauling or discarded because it is too small for canning.

8.7.5 Driftnets

The incidental catch of dolphin in tuna driftnets was a major concern and resulted in the banning of their use in the Western Central Pacific and in other parts of the world and was instrumental in brining the question of capture of unwanted marine life by fishing fleets to world attention.

8.7.6 Handlines

The small tuna handline fishery has low bycatches mostly of shark, which are released alive.

8.8 South Pacific artisanal/subsistence fisheries

In the artisanal and subsistence fisheries of the South Pacific islands very little of the catch is not utilised. The exception are fish for which there are taboos such as remoras and shark in certain islands. The known possibility of ciguatera poisons in some fish may lead to discarding of these fish. (FAO 1997)