Tuna Longline Fishery
Introduction
Longlining for large tunas in Hawaii began shortly after World War II. A variety of marlin and other pelagic species are also caught. The number of vessels increased rapidly in the late eighties. The Hawaii-based longline fishery has been the largest domestic commercial fishery in Hawaii since 1988.
Tunas and broadbill swordfish dominate the landings, but a variety of other pelagic species such as barracudas and sharks are also landed. Much of the longline effort occurs within Hawaiian waters, but fishing also extends far beyond the Exclusive Economic Zone (EEZ) into international waters. Although longline activity has been subdued recently compared to the rapid expansion in the late 1980s and early 1990s, the fishery continues to experience change.
The Hawaii-based longline fishery is the largest source of fresh pelagic fish in Hawaii and caters to local, U.S. domestic, and international markets. Recent developments in the Hawaii-based longline fleet are discussed here.
Vessels, Methods and Gear
Longline vessels operating out of Hawaii rapidly increased from 1987 to 1991. Vessels operating were stable from 1992 to 1994. The number of longline vessels operating dropped from 124 in 1994 to 110 in 1995. Vessel turnover was quite prevalent in 1995. The total number of fishing vessels has remained relatively stable in subsequent years amounting to 103 in 1996, 105 in 1997, and 114 in 1998.
In 1998 there were 164 Federal limited-entry permits issued for the Hawaii-based longline fishery. Of these 114 were active, 16 were new entries and 7 exited the fishery
Of the 114 active vessels in 1998, 17 were classified as small (< 56 feet), 55 were classified as medium (56-74 feet) and 42 were classified as large (> 74 feet)
One longline "set" is made per day of fishing, and for long main lines the deployment and retrieval may take almost 24 hours. Often the end of the line deployed first is retrieved last, so individual hooks may fish for a few hours, or all day; the average time is 12 hours. Traditionally the gear was set so that it fished primarily during daylight. For bait, Hawaii longliners use locally caught scad, imported squid, sardines, herring, and saury.
Longline fishing gear consists of a main line strung horizontally across one to 100 km of ocean, supported at regular intervals by vertical float lines connected to surface floats. Descending from the main line are branch lines each ending in a single baited hook. The main line droops in a curve from one float line to the next and bears 2-25 branch lines between floats. Fishing depth depends on the lengths of the float lines and branch lines, the sag in the main line and the position of the branch line. The deepest branch line positions are in the middle of the droop. Fishing depth affects the efficiency with which different species are captured.
Recent Developments
About 112 longline vessels were equipped with an electronic vessel monitoring system (VMS) by 1996. VMS is used to determine if longline vessels are fishing in areas closed to longline fishing around the Hawaiian Islands. Vessels operating within the EEZ are tracked by VMS, which also helps in locating a vessel in distress. The VMS will continue to be used through 1997.
The Federal longline logbook format was revised in 1995 to include additional information on fishing operations, oceanographic observations, and more pelagic species. Distribution of the new logbooks began in January 1995, and by April most of the data gathered were in the new format.
Five Hawaii-based longline vessels with limited-entry permits were contracted to receive shark fins from foreign longline vessels outside of the EEZ in 1996, up from three vessels in 1995.
Fishing Effort
The average days fished per trip (fleet mean) has increased steadily from 1994, when the days fished per trip were 9.8, to 11.0 days fished per trip, its highest since before 1991, in 1998.
Fishing effort is summarized by the number of days fished, which is the same as the number of sets and the number of hooks set. Number of days fished peaked in 1991. Days fished reached a low in 1994, and increased about 10% during 1995, then decreased slightly in 1996, before increasing again slightly in 1997, and increased to over 12,500 in 1998, the highest level since 1991. The increase in days fished by tuna and mixed trip types helped offset the decline in number of days fished by swordfish trips. The number of days fished on tuna trips has increased by more than 80% since 1991.
The number of hooks set fluctuated within a narrow range during 1991-94 but jumped to 14.2 million hooks in 1995, remained almost unchanged in 1996, increased to 15.6 million hooks set in 1997, and increased again to 17.4 million hooks set in 1998. The 1998 figure is the highest number of hooks set since before 1991 and the increased numbers of hooks set by tuna trips were responsible for the jump. Hooks set on tuna trips more than doubled from 1991 to 1998. In terms of the average number of hooks set per day, tuna trips have consistently shown the largest number since 1991.
The number of tuna trips steadily increased from about 1,200 in 1991 to about 1,700 in 1998. The average number of hooks set per day for tuna trips is now about twice the number of hooks set per day for either swordfish or mixed trips.
Landings
Longline landings have greatly increased since the late 1980s. Total landings were 23 million pounds in 1995, down from a peak of 25 million pounds in 1993. Total landings decreased in 1996 to 21.5 million pounds, then increased to a record 26 million pounds in 1997. Longline total landings in 1998 increased again to another record of 28 million pounds. Changes in composition of landings were caused by increased effort toward tuna.
Landings of two of the three major tunas were down in 1996. bigeye and yellowfin tuna landings decreased in 1996 from 1995, while albacore increased in 1996 from 1995, actually accounting for a larger part of the total landings than yellowfin tuna for the first time. The albacore catch in 1996 was almost twice the yellowfin catch in 1996. Bigeye tuna landings in 1996 were 4 million pounds. The landings data for 1997 showed an increase in all of the three major tuna categories, with bigeye tuna showing the largest landing total at almost 5.5 million pounds, second in total only to swordfish.
Bigeye tuna landings were at their highest level in at least 7 years. Bigeye tuna landings increased again in 1998 to a record level of more than 7 million pounds. Bigeye tuna landings have quadrupled in poundage since 1987.
Albacore tuna landings increased in 1997 to 3.6 million pounds, a record amount. Albacore tuna landings decreased in 1998 to about 2.5 million pounds.
Yellowfin tuna landings increased in 1997 to 2.5 million pounds, the highest amount in at least 10 years. As with albacore tuna landings in 1998, yellowfin tuna landings dropped to 1.5 million pounds in 1998.
Catch and Catch Composition
Tunas made up about half of the tuna trip catch, mostly bigeye and albacore. Composition of the catch for mixed trips showed sharks, at 35%, as the largest component, with swordfish next at 25%, followed by tuna and mahimahi. A marked difference in catch by area was also apparent. Tuna catches are largest during the fourth and first quarters.
The shift in effort has been toward tuna fishing. Record catches of bigeye and albacore tunas occurred in 1996, continuing the steady increase in tuna catches for the 6-year period ending in 1996. Bigeye tuna catch steadily increased in 1997 and 1998, with the 1998 catch a new record. The bigeye tuna catch in 1998 was more than double the catch in 1991. Albacore tuna catch increased to a record in 1997 but then dropped back in 1998 to 1995 levels.
Catch of yellowfin tuna fluctuated over the period 1991-1996, peaking in 1995 and, in 1996, dropping back to the norm for the period 1991-1996. Yellowfin tuna catch increased to a record high in 1997 but fell back to 1995 levels in 1998. In terms of total landings by species, bigeye and albacore are the leading fish retained. The species with the most dramatic rise in number of fish retained is albacore tuna, increasing from 14,051 in 1991 to 71,079 in 1997, before dropping back to about 50,000 in 1998.
Fish Size
The average size of longline-caught fish is expressed in round (whole) weights. Bluefin tuna was the largest tuna caught by longliners, showing a steady increase in mean weight from 184 lb in 1991 to 269 lb in 1995, before dropping back to 223 lb in 1996. Bluefin tuna landed mean weight increased to 239 lb in 1997, before dropping to an 8-year-low of 177 lb in 1998.
The mean weight of bigeye tuna showed little variation from 1987 to 1995, ranging from 76 lb to 87 lb, before dropping to 64 lb in 1996. Bigeye tuna mean landed weight increased to 71 lb in 1997 and increased again in 1998 to 74 lb, returning to its average weight range from 1987 to 1995.
Yellowfin tuna weigh more than bigeye and show more weight variation. The mean weight of yellowfin tuna dropped from its peak of 118 lb in 1991 to 80 lb in 1996, its lowest level in 9 years. Yellowfin tuna mean landed weight increased to 89 lb in 1997, but decreased again in 1998 to 76 lb, an 11 year low.
Albacore tuna are the smallest of the four tuna categories, and their landed weight steadily decreased from 62 lb in 1987 to a low of 41 lb in 1994, before recovering to 55 lb in 1998, its highest level since 1989. Mean weight also differed between trip types.
Market Value
Longline ex-vessel revenue has grown considerably since the late 1980s: from $10.5 million in 1987 to $43 million in 1995, after peaking at $53 million in 1993. Longline ex-vessel revenue remained at about $43 million in 1996, before increasing to $50 million in 1997, slightly below the 1993 peak. Longline ex-vessel revenue decreased to $47 million in 1998.
The largest component is from tuna, which made up over half of the total longline revenue in 1996 and again in 1997. In 1998 tuna made up 60% of the total longline revenue.
The tuna categories that have shown sizeable increases in revenue in the last 11 years are albacore and bigeye. Albacore tuna in particular have shown a dramatic increase in ex-vessel revenue, rising from only $520,000 in 1987 to $4.5 million in 1997, before dropping back to $3 million in 1998. The largest single component in 1998 ex-vessel revenues comes from the tuna category, specifically bigeye tuna at about $21 million.
Yellowfin tuna contributed $7 million in revenues in 1997, the third largest amount. Yellowfin tuna revenue again in 1998 contributed the third largest amount of revenue with a total of $4 million.
Fourth place in terms of total ex-vessel revenue in 1997, at $4.5 million, was occupied by albacore tuna, which has grown by a five fold amount since 1991, an increase of 400%. In 1998 albacore tuna again were in fourth place in revenue at $3 million.
Market Price
Ex-vessel prices are based on actual or estimated whole weight, depending on the degree of processing or damage.
Tunas are graded on several characteristics including observable features, anticipated shelf-life, and muscle quality. There are substantial variations in price for tuna. The best quality tuna, bluefin, is highly ranked in the sashimi market, especially in Japan which has the highest prices in the world. Bluefin tuna prices reached an all-time high of $18.26 per pound in 1996, before declining to $15.59 per pound in 1997, and declining further in 1998 to $7 per pound.
Bigeye tuna prices were consistent from 1987 to 1997, in the mid $3-per-pound range. Bigeye tuna prices declined in 1998 to just under $3 per pound, their lowest level in more than 11 years.
Yellowfin tuna prices increased steadily from about $2 per pound in 1987 to about $3 per pound in 1996, before declining to $2.68 per pound in 1997, and then declining further to $2.50 per pound in 1998.
Albacore tuna prices declined from about $1.50 per pound in 1987 to about $1.25 per pound in 1998.
Prices paid per pound in 1997 were albacore tuna at $1.23 per pound, bigeye tuna at $3.22 per pound and yellowfin tuna at $2.68 per pound.
Prices paid per pound in 1998 were albacore tuna at $1.24 per pound, bigeye tuna at $2.97 per pound and yellowfin tuna at $2.50 per pound.