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!SCTB11 and Bycatch Research Group Meeting 1: Issues and Workplan June 1998, Honolulu DRAFT AGENDA

Introduction

2. What are the issues? - What species/areas/fishing methods does the BBRG need to cover? What are the current and potential issues for the western and central Pacific tuna fishery? What kind of scientific advice is required? Who requires it? How will they use it? JRob Campbell Billfish fisheries off eastern and related research. WP26 Seabird bycatch and the development of a threat abatomont plan in, Australia.

3. Review of current and future monitoring, research and assessment O 4.1+tLwiM - What national and regional programs are relevant to the BBRG? vV Keith Bigelow Estimates of longline billfish catch in the Western Pacific Ocean. WP27 Peter Williams Review of shark bycatch in Western Pacific tuna fisheries.

4. Approaches to assessing the status of billfish and bycatch - Analytical approaches. - Data sources and requirements. Pierre Kleiber Turtle bycatch in . Tim Lawson Estimation of bycatch in western and central Pacific tuna fisheries.

5. Summary of work plan and action items

6. Session close Billfish Fisheries off Eastern Australia and Related Research

by

Robert Campbell

CSIRO Division of Marine Research, Hobart, Australia

Paper presented to the 11* meeting of the Standing Committee on Tunas and Billfish

May SO1"- June 6lh, 1998 Honolulu, USA Billfish within eastern Australia

1. Introduction

Six species of billfish are found in Australian waters - black ( indica), blue marlin (A/, mazara), (Tetmpturus audax), (Istiophorous platypterus), (T. augustirostris) and broadbill (Xiphias gladius). All these species are highly prized by the recreational fishers and form valuable game fisheries. Several of these species also form valuable components of the longline fisheries within Australian waters.

Until the expansion of the domestic longline fishery over the last decade the commercial catch of billfish was dominated by that caught by Japanese longliners operating in the waters off eastern Australia. While and bigeye tuna are the principal target species, this fleet also targets broadbill swordfish and striped marlin, with black and blue marlin being important by-catch species. In recent years broadbill swordfish has become a major target species for the domestic longline fishery.

In recent years, the potential for significant interaction between the recreational fishery for and the domestic tuna longline fleet in northern Queensland has helped to focus attention on the catch of billfish within the waters off eastern Australia. In this paper a brief outline is given of the fisheries catching billfish and the nature of the research conducted in recent years. This paper also updates the more detailed report concerning the catch of billfish within the eastern AFZ given in Campbell et al (1996).

2. Recreational Game Fisheries off Eastern Australia

Gamefishing in Australia has a long and rich history. The first gamefishing rules in Australia were drafted in 1908 for the gamefishing section of the Anglers' Club. This was closely followed by the first marlin to be captured on rod and reel in Australia (and quite possibly in the world), which was taken by Dr Mark Lidwell off Port Stephens in 1910 - a black marlin, 6'3.5"long. Sporadic reports of marlin captures are recorded after that: time. In 1930, the Newcastle Deep Sea and Game Fishing Club was formed at Bundabar (later to become the Newcastle and Port Stephens Game Fishing Club). However, the specialist gamefishing club, the Swordfish and Funny Club, was formed in 1934 on Montague Island. The Bermagui Big Game Anglers Club was formed in the following year, and it is interesting to note that these pioneer clubs still exist today. The Arnerican author, was a well-known gamefisherman, and first visited Australia in 1936. He fished off Bermagui, and made a number of notable marlin captures, which had the effect of putting Australia on the world gamefishing map. In 1938, the first major gamefishing tournament was held, to celebrate Australia's sesquicentenary (150 years). The competition was won by a female angler, Mrs Jessie Sams, with a 3301b striped marlin, caught off Ulladulla.

On 30 June 1938, the Game Fishing Association of Australia (GFAA) was formed, and in fact, this organisation helped to precipitate the formation of a world body, the International Association (IGFA), which was formally founded on 7 June 1939. Since that time, gamefishing has gained in popularity, especially on the east coast with boat-based (as opposed to shore-based) being the clearly predominant method. Many world record fish have been caught in the region, perhaps most notably, black marlin off the , between and Lizard Island. That area is now regarded as one of the best marlin fishing areas in the world for large fish.

Organised sportfishing in Australia has a shorter (but not less dynamic) history than gamefishing. The national sportfishing body (ANSA) was formed in 1969. In the same year, the Cairns Sportfishing Club was formed, with St. George and Sportfishing clubs forming Billfish w.-vhiii eastern Australia

later that year. Since that time, the number of sportfishing clubs on the east coast (and elsewhere in Australia) has grown significantly. Currently there are more than 104 clubs which operate in the eastern states, having in excess of 5,000 members. Importantly, the approach to competitive fishing by the ANSA clubs is different from that of the gamefishing clubs, whereby point scoring for captures focuses on a 'big fish' approach (often over time) resulting in many fish either not being taken or weighed. Many ANSA anglers also release fish without tagging.

Charter fishing for tunas and off eastern Australia probably had its embryonic beginnings when Zane Grey chartered boats to fish for marlin off Bermagui in 1936. However, the first real 'fleet' of charter boats developed in Cairns in the late 1960s and early 1970s, in response to the obvious potential for capturing and tagging giant black marlin in these waters. Because of the marked seasonal nature of the fishery (September-December) the size of the specialist fleet has varied over time, but is believed to average about: 20 boats. A smaller Brisbane-based charter fleet has also developed (about 10 boats), many of which travel to Cairns for the season, but also fish the black marlin/sailfish grounds off Cape Moreton from December through April. Over the last decade, the Brisbane fleet has proved the 'Cape Moreton Wide' grounds for blue marlin, with excellent strike rates being reported regularly through the first half of each year. Indications are that a minimum of around 50 (and possibly up to 100) charter operators existed along the east coast in the late 1980s. Some two-thirds of these were located in Queensland, with most of the rest in . Tagging of target species is a predominant activity for these operators, especially for billfish (and more so in north Queensland).

Catch and Effort Data Estimates of the number of billfish caught within the eastern AFZ by the non-commercial sectors are currently not available. The compilation of catch and effort data for the recreational/gamefish sector is particularly difficult given the number of individual involved, the spatial spread of the effort and the non-commercial nature of the activity. The lack of catch and effort information from the recreational sector presents problems in gaining an adequate understanding of this sector and for evaluating potential fishery interactions. However, a number of attempts to ascertain the effort and the catch in this fishery have been undertaken over the last decade.

In the late 1980s the Australian Fisheries Service commissioned a survey of the for tunas and billfish along the east-coast of Australia. The primary purpose of the study was to identify and evaluate a cost-effective system for the routine collection of catch and effort data from recreational fishing activities. Identification and evaluation of existing data was also sought. Commencing in 1989 the project involved extensive discussions with a range of organisations, including angler clubs, tournament organisers, charter operators and tackle shop owners. Three surveys were also conducted, including a comprehensive study of nearly 600 affiliated angler clubs. A range of research options for future data collection were identified. A detailed description of the project and the results is given by West (1990) while an overview is given in Ward (1991).

One of the options identified in the above study was the possibility of collecting catch and effort data from the major component of the organised game fishery through modification of the 'radio schedule' system used in gamefishing clubs and tournaments. To this end funding was made available in 1994 to initiate the collection of this data. The project aimed to integrate a catch-effort monitoring system within the existing practice of mandatory regular radio reports (known as radio 'scheds') which are used in organised game fishing activities such as competitions, tournaments and point scoring days. The radio reporting system operates as a safety measure, but also keeps the fleet informed of fishing success of the competing vessels. Billfish v/ithin eastern Australia

Funding for the project has continued with the operation of the operation taken over by the New South Wales State Fisheries in 1997. A standardised radio 'sched' sheet has been designed and has been successfully used at most of the major game fishing competitions along the east coast as well as a number of smaller events. The sched sheet incorporates and standardises the desirable features of the numerous club sheets previously used by various clubs, and most importantly, adds information on duration of time fished and total catch which enables the reliable collection of catch and effort data from this sector of the recreational fishery. In addition to monitoring the reported catch, the use of field interviewers has also been used to collect further details to enable incorporation of the entire daily catch and effort for given boats. This allows all fish to be recorded such as fish that would not have otherwise been recorded on the sched such as fish weighing less than the breaking strain of the line, undersized billfish, non-point scoring fish and so on. This category has proven to be significant for some tournaments. A report detailing the monitoring system and summarising the data collected to date is nearing completion (Pepperell and Henry, 1998).

For another component of the recreational fishery, the non-organised ('leisure') anglers, considerably less is known. However, a feasibility study has recently been completed on conducting a National Recreational Fishing Survey within Australia (West, 1998). This survey, which is to be undertaken during the next two years, has as one of its objectives the estimation of the catch by species from all forms of recreational fishing within Australia. Through this survey an estimation of the catch of billfish within eastern Australia waters will also be obtained to fill this gap in our current knowledge.

Tagging The greatest change in gamefishing in the last 10 to 20 years has been the move to instead of capture and kill. This trend to tag and release has been the result of cooperation between fishers and scientists. Tag and release studies are potentially useful in studying movements and population structure of such as billfish.

There is anecdotal evidence of marlin tagging off New South Wales as early as the late 1930s, However, organised tagging of billfish (black marlin) off eastern Australia (mainly off northern Queensland) began in the late 1960s under a program run by the US National Marine Fisheries Service. Between 1967 and 1977 over 2,500 black marlin off northern Queensland were tagged and released and 60 recoveries were reported (Squire and Neilsen, 1983). Since that time, a variety of programs have tagged all the species of billfish species found in Australian waters. The most important of these programs has been that managed by New South Wales State Fisheries which has coordinated the cooperative tagging of gamefish by anglers since 1973, eventually superseding the NMFS program in the late 1970s. This program covers tagging around the entire Australian coast. While all recognised species of marine gamefish are eligible for tagging, a few species dominate. Annual reports detail the number of releases and recaptures by species for each year. A summary of the number of billfish tagged within eastern Australian waters under the NSW program is given in Table 1.

Recapture rates of billfish tagged off eastern Australia are low (Table 1), but apparently these rates are comparable with those obtained by similar tagging programs elsewhere (Squire, 1987 and Mather et al, 1975). A general description of the tagging program and the results of movement behaviour observed in the data up until the late 1980s is given by Pepperell (1990a,b and 1991). A further description of the data collected up until the mid-1990s is given in Campbell etal (1996).

Mortality of billfish due to tagging remains unknown to a large degree. While other plausible reasons can be given for the low return rates from recreational tagging, including the chance of a recovery being low due to a large population, a high mortality due to tagging may also Billfish within eastern Australia

Table 1. Annual number of billfish tagged and released in waters off eastern Australia as recorded in the NSW Fisheries Research Institute database in Sydney. Year Black Blue Striped Broadbill Sailfish Spearfish Marlin Marlin Marlin Swordfish 1974 46 2 1975 72 1976 70 2 1977 583 2 14 1978 534 1 1 27 1979 605 53 1980 673 1 130 1981 591 2 1 138 1982 755 4 134 1983 1,065 3 11 293 1984 1,061 1 4 219 1985 1,114 9 16 296 1986 1,633 20 28 4 292 1987 1,265 9 - 40 3 327 1 1988 1,071 46 41 467 1989 1,222 146 129 1 309 4 1990 1,979 101 132 3 330 3 1991 2,168 107 147 4 532 3 1992 2,296 80 181 1 366 6 1993 1,496 63 217 6 745 20 1994 710 113 319 4 176 11 1995 835 63 472 10 202 32 1995 1,946 88 1,031 3 274 6 1997 2,788 68 1,071 1 306 Total 26,552 921 3,849 40 5,632 86 b) Recaptures N 184 2 2 2 115 0 % 0.69% 0.22% 0.05% 5.00% 2.04% 0.00% contribute to such low return rates. Various .attempts have been made to assess the mortality of tagged and released fish. Within Australia black marlin were tagged and tracked in the waters off Cairns using acoustic tags (Pepperell and Davis, 1998). Of the eight fish tagged and tracked, one was taken by a shark, two tags were deemed to have fallen out, and five fish were still alive at the end of the tracking episode (ranging in time from 8 to 28 hours). While the sample size is small, these results can be added to the results from similar work carried out elsewhere. A summary of the results from these projects is given in Table 2. Based on this information the survival of released marlin is estimated to be between 84 and 90 percent giving an estimated mean mortality of around 13 percent. However, some caution needs to be placed on the above results. Most tracking events usually last less than 30 hours and the survival rates given above may only be relevant for the first day or so after release. The continued survival rate of fish after this time remains unknown.

2. Commercial Catch of Billfish

Since the start of Japanese longlining within the waters off eastern Australia in the early 1950s billfish species have formed a regular, if somewhat small, component of the total catch taken. Following the declaration of the AFZ on 1st November 1979, a number of restrictions were placed on the operations of Japanese longliners fishing off eastern Australia. These Table 2 Summary of acoustic tracking data used to calculate the survival of tagged and released billfish (from Campbe

Number Number Duration of Size Range Species Location Tracked Survived Cause of Death Tracks (hrs) of Fish (kg)

Blue Marlin Hawaii 4/5* 2 Shark. Unknown 5 to 23 70 to 270 Sailfish Florida 8 7 Shark 3 to 28 11 to 28 Blue Marlin Hawaii 6 6 7 to 42 60 to 160 Blue Marlin Hawaii 5/6* 5 Shark 15 to 120 60 to 220' Striped Marlin California 11 11 3 to 48 50 to 80 Striped marlin Hawaii 6 - 5 Unknown 14 to 51 37 to 57 Blue Marlin US Virgin Is 6 '6 up to 6 Black Marlin Queensland 6/8* '5 Shark 8 to 28 120 to 400

TOTALS 52/56 47

* In these cases it is uncertain whether the fish died or the tag fell out of the fish soon after release.

Note: All fish were caught by rod and reel, except for the 6 striped marlin in Hawaii which were caught on longlin soak time of 4 to 8 hours. Billfish within eastern Australia

restrictions resulted in a number of areas becoming permanently closed to Japanese vessels. While many of these restrictions were to reduce interaction with the expanding domestic tuna longline fishery, in some instances these restrictions were intended to reduce the interaction between Japanese longliners and the northern Queensland recreational and charter boat fisheries which target billfish species. To this end, since 1986 Japanese longliners have agreed to a voluntary code to release all black or blue marlin alive at the time of retrieval. A detailed summary of these arrangements is given by Caton and Ward (1996).

The annual catch of billfish (by species) reported by Japanese longliners operating off eastern Australia is given in Table 3. The catches are based on the logbook data stored within the Australian Fishing Zone Information System. The logbooks only record fish retained and so the annual catches do not include the black and blue marlin which were discarded under a voluntary agreement operating since 1986. Estimates based on observer data from the Coral Sea region puts the discard rate at around 30 percent. Adherence to this agreement on non- observed vessels is not known. An analysis of the trends in black marlin abundance and stock composition off eastern Australia using the data from the Japanese longline fishery between 1955 to 1991 is given in Williams et al (1993).

Table 3. Reported number of billfish caught and retained by Japanese longliners operating off eastern Australia. Year Number Black Blue Striped Broadbill Sailfish & of Sets Marlin Marlin Marlin Swordfish Spearfish 1980 1,797 931 510 3,476 6,488 461 1981 5,325 1,723 1,984 10,637 12,964 907 1982 5,474 4,131 5,093 16,906 20,976 1,727 1983 3,656 1,997 2,016 4,300 10,109 1,117 1984 3,037 1,830 994 5,011 11,619 764 1985 2,897 1,115 1,360 4,073 13,055 864 1986 2,426 273 709 2,931 12,082 325 1987 2,841 1,942 1,577 3,070 13,043 1,698 1988 4,811 2,202 6,025 6,212 18,739 1,976 1989 5,802 971 4,653 8,705 15,949 1,819 1990 4,040 491 3,728 4,662 10,095 3,342 1991 2,225 255 319 2,753 9,473 564 1992 2,088 171 3"85 2,199 8,642 586 1993 2,514 345 604 3,255 5,392 1,877 1994 2,542 742 702 4,264 7,034 1,683 1995 1,053 145 462 2,587 2,556 525

Billfish are also caught by domestic longliners operating within the waters off eastern Australia. However, the catch for this component of the fishery remains more uncertain due to significant under-reporting of the catch of marlin species. The catch of broadbill swordfish, which has become a principal target species in recent years, is however better known. In 1996 the number of broadbill swordfish caught by domestic Australian longliners was over 9,000 in number (around 700 tonnes), having increased by almost an order of magnitude in just two years.

3. Interaction Issues: The Coral Sea Region

The major tuna and billfish species which occur in the Coral Sea region of the Australian Fishing Zone are of considerable interest to both the commercial and recreational sectors of the Australian fishing industry. Since the 1960s the region between Cairns and Lizard Island to the north has developed into a major recreational/charter-bont fishing region for black Billfish within eastern Australia

marlin. Game fishers from around the world are lured to the region in the hope of hooking a "thousand pounder" - large females associated with the spawning/pre-spawning aggregations which occur during the spring months. The region is the only known spawning region for black marlin in the Pacific.

To assist in the development of gamefishing tourism in the Coral Sea rim countries, an atlas describing the distribution and seasonal occurrence of the major billfish species in this region has been produced (Williams, 1994). The summaries of the seasonal catch rates are based on the data from Japanese longliners betweenl962-1970.

The Japanese longline fishery began fishing in the Coral Sea region in the early 1950s. Fishing lasted from October to March with two distinct seasons during this period. From October to December, black marlin comprised more than half the catch (by weight), while from January to March the black marlin disappeared from the fishing grounds and yellowfin tuna became the dominant catch. After the introduction of the AFZ in 1979 two major closures and a voluntary release agreement were directed specifically at reducing the catch of black and blue marlin in this region. The restricted areas, together with the year of closure, are shown in Map 1. The closed areas have since become known as Area E and have a combined area of approximately 172,000 square kilometres.

Map 1. Map showing the region known as Area E off the north-eastern Queensland coast. The dates indicate the years in which each section was closed to Japanese longliners.

Since 1987 a domestic longline fishery operating out of Cairns has developed targeting yellowfin and bigeye tunas. This fishery underwent considerable expansion in the early 1990s with a combined catch of yellowfin and bigeye in the mid-1990s reaching approximately 400 tonnes. To date thirteen permits have been granted which allow vessels to operate within Area E, though only eight vessels are presently operating there.

While the commercial fishery does not target billfish, the potential for significant interactions between the domestic longline fishery and the recreational fisheries within Area E over the Billfish within eastern Australia catch of billfish became a major management concern in 1995. Poor catches of black marlin by the recreational sector off Cairns in late 1994 triggered concerns that local abundance of black marlin was becoming depleted due to the by-catch of this species by the domestic longliners. This concern led to calls for the cessation of all commercial longlining within Area E and pressure to prohibit the taking of all marlin species by commercial operators. In response the Australian Fisheries Management Authority (AFMA) identified the interaction between the commercial and recreational sectors of the Eastern Tuna and Billfish Fishery as an important research area that needed to be addressed. A preliminary analysis of the situation by the Billfish Assessment Group (Campbell et. al. 1996), however, highlighted the complex nature of this fishery interaction issue and made a number of recommendations for future research. One of the conclusions was that in order to gain a better understanding of this issue, the collection of verified catch and effort statistics would be required from all sectors catching billfish in this region.

Observer Surveys within Area E

Past studies into the catch of black marlin in the Coral Sea region mainly focused on the analysis of historical Japanese longline data (Williams et al. 1993, Ward 1996, Campbell 1996). However, these studies were seen as having little relevance to the operations of the present day domestic tuna fishery as the nature of the longline operations is in many regards quite different.

While there existed much anecdotal opinion concerning the catch of billfish by domestic longliners, there was little hard data on which to base sound management decisions. In order to overcome this lack of information CSIRO undertook a study to collect observer verified catch and effort statistics from a number of the domestic longline vessels operating within Area E. Furthermore, by monitoring the nature of the catching process using electronic monitors attached to the fishing gear, the project also focused on the evaluation of the longline catch in relation to the vertical distribution of the tuna and billfish resources within this region. The possibility of habitat segregation of the tunas and billfish in this region was seen as providing some assistance in developing practical means to minimise the by-catch of marlin species by the domestic longline fleet and in turn help mitigate the interaction between the different fishing sectors.

Two surveys were undertaken. The first survey was during spring 1995 (12'" October - 13"1 December) when two observers were placed aboard vessels operating within Area E. The second survey was undertaken during winter 1996 (16'" May - 221"1 August) when only a single observer was deployed. The timing of the two surveys was to observe differences in the fishing strategies of the fleet and the catch due to the seasonality in both the target and by-catch species. The first survey coincided with a period in which spawning aggregations of tuna occur (usually around the full moon) and when there is also a high seasonal abundance of black marlin. On the other hand, during winter neither of these activities take place.

Together with the collection of the usual catch and effort information, electronic monitors were used to record more detailed information on otherwise unobservable aspects of the fishing process. Temperature-depth recorders were used to monitor the depth of the longline and the temperature profile of the water column. The information on fishing depth was combined with the distribution of capture hook position to evaluate the distribution of the principal species caught in the water column. Hook-timers were also deployed to provide information on the time of fish capture. Knowing the time the hook was placed in the water allows calculation of the soak time of the hook and the bait before being bitten. Billfish within eastern Australia

Complete details of these surveys and results are given in Campbell et al (1997a,b) and were summarized in a paper presented at the 7'h meeting of the Western Pacific Yellowfin Tuna Research Group with was held in Fiji in June, 1997 (Campbell et al, 1997c). Some of the major findings of the study are listed here: • Based on the effort recorded in commercial logbooks and using the catch rates during the two observer-based studies it is estimated that 1,450 black marlin were caught by longliners within Area E in the 12 month period from August 1995 to September 1996. • The mortality of the black marlin caught on longlines was observed to be about 30 percent. For the 12 month period from August 1995 to September 1996, the estimated black marlin mortality due to longlining in Area E was estimated to be about 450 fish. • The catch rates of black marlin averaged about nine fish per 1000 hooks during the spring survey while no black marlin were caught on the observed vessels during the winter months. Like many other pelagic species, black marlin are highly migratory and appear to spend most of the year in other parts of the Western Pacific or further afield. It is believed that they migrate into Area E during the spring months to spawn or feed, with most fish having left the area by Christmas. • Marlin mortality was found to be related to the duration of the set. As the duration of a set increases from 3 to 16 hours, the estimated mortality of black marlin increases from about 20 to 50 percent. The present restriction limiting longliners to set no more than 500 hooks at any one time within Area E was seen as reducing the total number of hooks in the water at any one time. Fewer hooks also resulted in shorter sets v/hich increases the chance of any marlin hooked on the lines surviving. • Most black marlin were caught on hooks which fished at depths less than 75 metres, whereas the targeted tuna species were usually caught on hooks fishing deeper. By ensuring that their hooks fish in waters deeper than 75 metres, the longline fishers should be able to further reduce the catch of black marlin and at the same time increase their catch of tuna. The recent development of depth monitors will help longliners achieve this result.

Following the completion of the observer based surveys, and the publication of the results, articles were placed in popular fishing to help communicate the results to a broader audience (see for example Campbell et al. 1997d, Johnson 1997). While the study helped to clarify a number of issues concerning the catch of black marlin by commercial longliners operating within Area E, the level of interaction between the commercial and recreational fleets still remains uncertain at this stage. It is a complex issue that requires further research. For example, if there is a large throughput of black marlin within the area, then the numbers caught by the longliners should only have a minimal impact. On the other hand, if the throughput is small, then the impact will be larger.

To assist in our understanding of this issue a small pilot study into the movement and residence times of black marlin within Area E is currently being undertaken using pop-up radio tags. Collection of historical data from charter boat operators is also underway to help identify possible changes in the annual time series of strike rates in this fishery. It is of interest to note whether the two area closures imposed on Japanese longliners in 1980 and 1991 respectively, together with the increase in domestic longline activity in the area, has had any noticeable effect on strike-rates in the recreational fishery. Any increase in strike-rates after the closures and any decrease in strike-rates with the increase in domestic longline activity would help determination of the level of interaction between longline activity and recreational strike-rates in the region.

Finally, the black marlin found off north-eastern Queensland are thought to be part of the much larger stocks which inhabit the Western Pacific Ocean, if not the whole Pacific. Conservative estimates of the number of black marlin caught and retained by longliners / /

Billfish within eastern Australia

within the Western Pacific are between 20,000 and 30,000 per year. Large numbers of black marlin are also caught by longliners and purse seines in the Eastern Pacific. The number of black marlin mortalities resulting from longlining activities within Area E is therefore small (about 2 percent) by comparison. While the status of the black marlin stocks in the Pacific currently remain uncertain, any declines in total stock abundance are therefore likely to be caused by factors exogenous to Area E.

Most black marlin caught by game fishers are tagged and released. Estimates of the number tagged each year vary and are imprecise though in recent years numbers have averaged about 1,100. A preliminary analysis of the gamefishing data indicates that strike rates have not changed appreciably since the early 1980s (Campbell et al, 1996). However, 1994 was a poor year for the gamefishing sector in this region. The reasons for the apparent absence of black marlin during the 1994 season remain uncertain, although the prevailing El Nino conditions at the time may have modified the movement patterns of the black marlin into and within Area E. On the other hand, there were record catches of juvenile black marlin along the east coast of Australia during 1997.

Under the terms of their licence conditions, the longliners which fish within Area E are not allowed to retain any black marlin caught between September and January. For these months, which correspond with the main black marlin season, all black marlin caught are required to be returned to the sea. Furthermore, the East Coast Tuna Boat Owner's Association supported the extension of this ban to the entire east coast longline fishery through a voluntary code of practice. However, whether or not all fishers followed this code remained uncertain as allegations of black marlin landings continued to be made.

After continued lobbying from gamefishers and media coverage of the issue the Commonwealth Government announced on 5"' November 1997 the intention to introduce a new law prohibiting the landing of all black or blue marlin by commercial operators within Australian waters. Operators who break the ban will face fines of up to $12,500. This new law has recently been introduced into Parliament and should be passed during the current term. Also in November 1997, an agreement was reached between the major game fishing associations in Queensland and the tuna longline fishers who hold Area E permits for a co- regulatory code of conduct for within Area E. This agreement, while recognizing the right of the Area E permit holders to have year round access, also puts into place a wider voluntary ban in Area E on- the taking of all billfish except for broadbill swordfish.

To assist both commercial and recreational fishers identify the various billfish species a guide has been developed which provides detailed descriptions of the various billfish species found in the Indo-Pacific region (Pepperell and Grewe, 1998). This guide will help fishers identify billfish when hooked but still in the water prior to release or landing, and also provides details for identification of dead billfish landed whole or dressed in various ways. The guide also describes a genetic test recently developed by CSIRO that can be used, where necessary, to provide unambiguous species identification (Ward et al, 1997). Such identification may be required in cases of disputed species type, particularly in cases when external diagnostic features such as fins or the head have been removed. The test will also be useful for identiying small juvenile fish which can be difficult to identify from external characterisitcs alone. The test, based on DNA fingerprinting, requires only a small piece of tissue and can therefore be used to identify live animals through muscle biopsies of through fin clips. Billfish within eastern Australia

References and Further Reading

Anon (1994) Fisheries Assessment Report: East Coast Tuna and Billfish Fishery 1994. AFMA, Canberra.

Anon. (1996) Code of practice for EC tuna operators. The Queensland Fisherman, April, p26-27

Campbell, R. (1995) Background notes on the Tuna and Billfish Fisheries in the Coral Sea Region off north-eastern Australia. Report to Eastern Tuna MAC. Unpublished.

Campbell, R., Williams, D., Ward, P. and Pepperell, J. (1996) Synopsis on the Billfish Stocks and Fisheries within the Eastern AFZ. Report to Eastern Tuna MAC, 95pp.

Campbell, R., Whitelaw, W. and McPherson, G. (1997a) Domestic Longline Fishing methods and the catch of tunas and non-target speceis off north-eastern Queensland. (Is' Survey: October-December, 1995). AFMA, Canberra, 70pp.

Campbell, R., Whitelaw, W. and McPherson, G. (1997a) Domestic Longline Fishing methods and the catch of tunas and non-target speceis off north-eastern Queensland. (2'"' Survey: May- August, 1996). AFMA, Canberra, 45pp.

Campbell, R., Whitelaw, W. and McPherson, G. (1997c) Domestic Australian Longline Fishing methods and the catch of tunas and non-target speceis off north-eastern Queensland. Working paper presented at the 7'" meeting of the Western Pacific Yellowfin Tuna Research Group held in Nadi, Fiji, June 18-20, 1997.

Campbell, R., Whitelaw, W. and McPherson, G. (1997d) Black marlin and Area E - the facts. Professional Fisherman, 19(9) 22-24.

Hoey, J. J. (1996) Bycatch in Western Atlantic Pelagic Longline Fisheries. In Solving Bycatch: Considerations for Today and Tomorrow. Alaska Sea Grant College Program Report No. 96-03, University of Alaska, Fairbanks.

Johnson, K. (1997) Fishing for clues - can we help the marlin slip the hook. Ecos 92, 6-9.

Mather, F. J., Mason J. M. and Clark, H.L.(1975) Migrations of and blue marlin in the western north Atlantic Ocean. Tagging results since May, 1970. In R.S.. Shomura and F. Williams (ed.) Proceedings of the International Bilfish Symposium. Kailua Kona, Hawaii, 9-12 Aug. 1972, Part 2: 211-225. NOAA Tech. Rep. NMFS SRF-675.

Pepperell, J.G. (1990a) The Australian cooperative gamefish tagging program, 1973-1987: Status and evaluation of tags. Proceedings of the International Symposium and Educational Workshop on Fish marketing Techniques, 27 June-1 July, 1988, Seattle, Washington.

Pepperell, J.G. (1990b) Movements and variations in early year class strength of black marlin Makaira indica off eastern Australia. In R.H. Stroud (Ed.) Proceedings of the International Billfish Symposium. II, 1-5 August, 1988, Kona, Hawaii.

Pepperell, J.G. (1991) A review of tuna and billfish tagging in the eastern Australian Fishing Zone. In P.J. Ward (ed) East Coat Tuna and Billfish Research and monitoring Workshop, 15- 16 march, 1990, Cronulla. BRS Working paper No. WP/17/91. Billfish within eastern Australia

Pepperell, J. G. and Grevve, P. (1998) A field guide to the Indo-Pacific Billfishes. (in prep.)

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