Swordfish Longline Fishery
Introduction
Landings from the U.S. Swordfish fisheries in the North Pacific Ocean increased steadily from 1970 through 1989 but rose sharply in the 90s. Three different U.S. swordfish fisheries, a harpoon and longline fishery in California and a longline Hawaii fishery in the North Pacific Ocean landed an estimated 3,500 metric tons worth $20 million in 1995. The Hawaii-based longline fishery contributed 78% of the total landings, amounting to about 2,700 metric tons.
Vessels, Methods and Gear
The number of vessels increased rapidly in the late eighties with swordfish being only a small fraction of the longline landings. Longline techniques used to target swordfish were introduced as time progessed. Domestic longliners from the Gulf of Mexico and the Atlantic swordfish fishery joined the Hawaii-based longline fishery and helped establish Hawaii as a major producer of swordfish.
A federal moratorium capping the number of longline vessels at 167 was initiated in 1991. The number of active longline vessels peaked at 141 in 1991 with 114 of those vessels fishing for swordfish as their primary or secondary target. Some of these longline vessels fished for swordfish throughout the year. Interest has subsided with only 103 active longline vessels in 1996 of which 58 fished for swordfish as their primary or secondary target species.
The area fished by the Hawaii-based longline fleet ranged from Lat 5?N to 48?N and from Long 170?E to 130?W with the area of fishing directed toward swordfish typically occurring north of the Hawaiian Islands.
Trips are usually about 1 month long but have been known to exceed 2 months. Longlining for swordfish occurs year round, but activity is highest in the first and second quarters.
The basic unit of gear is the main line, made of monofilament and stored on a large hydraulic reel. Eight hundred to 1000 hooks are attached to 30 to 40 miles of main line on a typical fishing day. Branch lines are baited with large squid. Light sticks are also attached to the branch lines. Swordfish longline gear is usually set in the evening, soaked overnight, and hauled the following morning. Swordfish are headed, gutted, finned, and packed in ice.
Landings and CPUE
The Hawaii-based longline fishery is the largest producer of swordfish of all the U.S. North Pacific swordfish fisheries. Swordfish landings began to increase in 1989 when a few vessels began having some success at targeting swordfish. Swordfish landings peaked at 5,942 metric tons in 1993, and declined to 2,726 metric tons in 1995. Although swordfish landings decreased substantially in 1994 and 1995, swordfish maintained its status as a major component of Hawaii longline landings.
Swordfish CPUE varied substantially depending on targeting practices. Swordfish CPUE for trips specifically targeting swordfish peaked at 16.5 fish per 1000 hooks in 1992, dropped to 11.8 fish in 1994, and increased to 14.5 fish in 1996. Tuna-targeted trips had the lowest swordfish CPUE, while mixed target trips had intermediate swordfish CPUE throughout 1991-96. Swordfish-targeted trips usually have the highest swordfish CPUE in the first and second quarters and lowest levels in the third quarter. The relatively slow longline activity in the third quarter magnifies the seasonal decrease.
Catch Composition
For swordfish trips, sharks made up about half of the trip catch, and swordfish made up about one-third of the catch. 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.
The shift in effort has been toward tuna fishing. The swordfish catch in 1996 dropped by over 50% from a peak in 1993. Shark catch continues to decline because of the reduction in swordfish effort. Swordfish trips were responsible for most of the shark catch.
Fish Size
The mean whole weight of swordfish increased from 119 pounds in 1988 to 178 pounds in 1992. Mean weight of swordfish was 171 pounds in 1995. Swordfish landed by longliners targeting swordfish had an average weight of 185 pounds in 1995 which was considerably larger than the 124-pound average weight of those caught by longliners targeting tunas.
Market Value and Price
Almost all of the swordfish landed in Hawaii are exported to the U.S. mainland and, therefore, are dependent on the U.S. mainland swordfish market.
Swordfish revenue accounted for the largest single component of total longline revenues as recently as 1994. In 1996 swordfish revenue of $14 million made up about one-third of the total longline revenue. Swordfish revenue of $14 million dropped to about one-quarter of total longline revenue for 1997. Swordfish revenue of $12 million in 1998 was again about one-quarter of total longline revenue. At this level revenues from swordfish were again the second largest contributor to total longline revenues in 1998. This was still a 50% drop from the 1993 peak of $26.5 million.
Swordfish prices, based on round weight, declined from $3.23 per pound in 1987 to a low of $1.92 per pound in 1992 but recovered slightly to abount $2.50 per pound in 1996. In 1997 swordfish prices resumed their decline, dropping to $2.21 per pound. Swordfish prices dropped to more than an 11-year low of $1.66 per pound in 1998.
Larger swordfish received a higher unit price than smaller fish.
Data Collection
The PIFSC Fishery Monitoring and Economics Program (FMEP) monitors the Hawaii-based longline fleet through Federal logbooks and collects market data.
Other sources of data originate from at-sea observer trips, research cruises, and voluntary tag-and-release, and recovery studies. Annual market samples ranged from 25% to 90% while at-sea observer coverage represented about 5%.
Each of the five data sets have unique characteristics that together provide a detailed description of effort, catch, biology, migration patterns, economic performance, amd impact on protected species. Linking some of the data sets also allows NMFS scientists to verify the accuracy of the data.