The Development and Decline of Hawaii's Skipjack

CHRISTOFER H. BOGGS and BERT S. KIKKAWA

Introduction the Hawaii skipjack tuna catch was and frequent spawning (Hunter et aI., small compared with the total Pacific 1986). Unlike populations of larger Historically, the pole-and-line, live­ catch of this species (ca. 870,000 t in tuna species (Miyabe, In press; Suzuki, bait fishery for skipjack tuna, 1990; IATTC, 1992; Hampton, In In press) and (Suzuki, 1989), Katsuwonus pelamis, was the largest press). skipjack tuna appear to be underexploited commercial fishery in Hawaii. Annual The Hawaii skipjack tuna fishery (Kleiber et aI., 1983; Hampton, In pole-and-line landings of skipjack tuna originally supplied only the local mar­ press). The absence of regulation in exceeded 2,500 metric tons (t) or 5.5 ket for fresh and dried tuna. The fish­ Hawaii's skipjack tuna fishery contrasts million Ib from 1937 to 1973 (June, ery expanded in the 1900' s because with the management of Hawaii's fish­ 1951; Yamashita, 1958; Uchida, 1976; 1 the ready availability of skipjack tuna eries for other and (Boggs Skillman, 1987; Kikkawa ), except was sufficient to support a cannery and Ito, 1993), and is justified by the during World War II (1941--45). The which provided access to outside mar­ apparent underexploitation of the stock record production of 7,400 t (16.3 mil­ kets. A sustained drop in the catch per and the declining size of the local fish­ lion Ib) of all species landed in 1965 unit effort (CPUE) of large (>6.8 kg, ery. by the pole-and-line fishery was un­ >15 Ib) skipjack tuna began in 1974. This review describes the Hawaii surpassed until 1991, when the Hawaii The decrease in CPUE was related to skipjack tuna fishery, its development longline fishery landed 8,000 t (all spe­ environmental changes affecting local through the 1970's, and subsequent cies combined). Even so, at its largest, fish availability (Mendelssohn2; Boggs, decline. Research on factors contribut­ 1988). Combined with increased fish­ ing to the decline are summarized and ing costs, market competition from the fishery community's attempts at I Bert S. Kikkawa. An update of the skipjack tuna, Katsuwonus pelamis, baitboat fishery in other tuna products, and the 1984 clo­ revitalization are described. Hawaii, 1971-83. Honolulu Lab., Southwest sure of the Hawaiian Tuna Packers, Description and Fish. Sci. Cent., NMFS, 2570 Dole St., Hono­ Ltd. cannery in Honolulu, these fac­ lulu, HI 96822-2396, unpub!. manuscr. Historical Development tors caused a major decline in Hawaii's skipjack tuna fishery during the late In Hawaii, skipjack tuna, commonly 1970'sand 1980's (Boggs and Pooley, called by its Hawaiian name "aku," is ABSTRACT-The pole-and-line fishery 1987; Hudgins and Pooley, 1987). The mostly caught by pole-and-line for skipjack tuna, Katsuwonus pelamis, was fishery has not recovered. (e.g., >99% through 1974, 72% in the largest commercial fishery in Hawaii Expanding for skipjack tuna 1990). This method uses live bait until its decline in the 1970's and 1980's. throughout the Pacific (Forsbergh, thrown from a to stimu­ The development and decline of the fish­ ery were strongly affected by fish avail­ 1980; IATTC, 1992; Hampton, In late a surface school into a feeding ability and marketing. A sustained drop in press) do not appear to have caused the frenzy. Fishing is then conducted fran­ the availability of large fish in the mid­ decline in Hawaii's fishery (Boggs and tically to take advantage of the limited 1970's appears to have been due in part to Pooley, 1987; Kearney, 1987; Sibert, time the school remains near the boat. a sustained environmental change. Avail­ ability oflarge fish subsequently increased, 1987), although further analyses may The pole and line are of equal length but the fishery continued its decline owing reveal negative impacts. Skipjack tuna (ca. 3 m) and are used with a barbless to low profitability and lack of markets. are relatively impervious to overfish­ hook with feather skirts which is The tuna cannery in Honolulu that fos­ ing (Boggs and Pooley, 1987; Hamp­ slapped against the water until a fish tered thefishery's expansion in the 1930's ton, In press) due to widespread distri­ strikes. Then the fish is yanked into closed in 1984. Unless efforts to increase the marketfor skipjack tuna become effec­ bution and reproduction, rapid growth, the vessel in one motion. The fish un­ tive, landings will probably remain at cur­ early maturity (Matsumoto et aI., 1984), hooks when the line is slacked so that rent levels of about 1,000 metric tons per the process can be repeated. year. The existing pole-and-line fleet may 2R. Mendelssohn. 1986. Environmental influ­ continue to decline with age, and the local ences on skipjack tuna availability. U.S. Dep. The authors are with the Honolulu Laboratory, market may eventually be supplied by other Commer., NOAA, Nat!. Mar. Fish. Serv., South­ Southwest Fisheries Science Center, National fishing methods (e.g., trolling), by new ves­ west Fish. Cent., Honolulu Lab., Southwest Fish. Marine Fisheries Service, NOAA, 2570 Dole sels, or by imports. Cent. Admin. Rep. H-86-l3C, 14 p. Street, Honolulu, HI 96822-2396.

55(2), 1993 61 The bait most often used is the an­ water may resemble a school of bait was surpassed in 1954 (Fig. I). During chovy Encrasicholina purpureas, com­ and partly obscure the view of the boat the 1950's through the early 1970's monly called by its Hawaiian name and fishermen. the fleet landed an average of about "nehu." Each fishing vessel seines for The Hawaiian Tuna Packers, Ltd. 4,000 t per year. Interannual variation bait in bays, harbors, and other shel­ cannery in Honolulu was established in catch was large, but no significant tered waters, and the bait is not "hard­ in 1917, enabling the fi shery to expand long-term trend was apparent from ened" for long-term transport or for beyond a relatively small fresh and 1948 to 1970 (Uchida, 1976). use more than a few days after capture. dried market. The greatest annual Total catch levels remained high de­ The fishery is limited to areas close to amount sold in the fresh and dried mar­ spite a decline in fleet size from 32 to the eight main Hawaiian Islands. Skip­ ket was 2,200 t (4.9 million lb) in fis­ 15 vessels between 1948 and 1971 be­ jack tuna are located by searching for cal year 1935 (i.e., July 1934-June cause 1) fishing efficiency increased bird flocks associated with surface 1935, Yamashita, 1958). The market as the proportion of Class II vessels in schools. Fishing trips seldom last for canned product allowed the fishery the fleet increased, and 2) the number longer than a day, and most vessels to expand to a peak of 6,100 t (13.4 of days fished per boat increased return to port each night. million Ib) in 1940 (Fig. 1) followed (Uchida, 1976). As a result, total stan­ The basic pole-and-line method in by a hiatus during WWII. From 1937 dardized effort in the 1970' s averaged use today was practiced in the 1800' s until the early 1980's most of the skip­ only slightly below that in the 1950's largely by native Hawaiians using ca­ jack tuna landed in Hawaii was canned. (Uchida, 1976; Skillman, 1987; noes (June, 1951). In 1900 the fishery Before WWII the fishery included Kikkawa l ) (Fig. 2). was relatively small, with total land­ up to 26 vessels (Hudgins and Pooley, From the 1970's to the present most ings of 190 t (0.4 million Ib, Fig. 1) 1987) and landed an average of 5,000 t of the active vessels have been the re­ sold in the fresh market (Yamashita, (2.3 million Ib) per year from 1937 to maining wooden-hulled sampans built 1958). Around the tum of the century 1940. Most vessels constructed before in the 1940's and 1950's. These ves­ Japanese immigrants began introduc­ WWII averaged about 31 t displace­ sels carry crews of 7-9 fishermen, and ing small (ca. 6 m) shallow-draft ment and had a bait-well capacity be­ frequently work 6 days a week. The wooden sampans with built-in bait low 3,000 L (800 gallons, defined as work is arduous and may begin with wells, followed by motor powered ves­ Class I vessels). Larger sampans, av­ bait seining at dawn followed by fish­ sels starting in 1907. In the 1930' s the eraging 58 t, were mostly built in the ing to dusk. One new steel-hulled ves­ vessels were redesigned to be larger, late 1940's and 1950's. These gener­ sel with about twice the displacement with deeper draft, flying bridges, pump­ ally had a bait-well capacity greater than (91 t) of the old wooden vessels en­ spray systems, and greater freeboard 3,000 L (defined as Class II vessels, tered the fishery in the 1970' s, but was l forward to give them better seaworthi­ Uchida, 1976; Kikkawa ). not very successful. ness (June, 1951). Pump-spray systems As new vessels were built, fleet size The agitate the water around the vessels increased to a maximum of 32 vessels Decline during fishing. To the fish, the agitated in 1948. The prewar landings record Since the mid-1970's the trend in Hawaii skipjack tuna landings has been downward (Fig. 1), reflecting both a decline in fishing effort (Fig. 2) and 8000 CPUE (Fig. 3). Current (1990-91) an­ 15 nual landings average <1,000 t (2.2 million Ib) (Ito3). By the mid 1980's 6000 -::e 12 I:l the number of vessels in the fishery Z' 0 '-' had fallen to nine (from 15 in 1971) ~ ] ~ 4000 9 '-' and in 1991 only six vessels were ac­ ~ tive, four active on a full-time basis. j 6 ~ Fishing effort dropped after 1979, fall­ 2000 j ing to 1,023 Class II fishing days in 3 1981 and 922 days in 1986 (Fig. 2). Another major drop in fishing effort 0 occurred in 1989-90 (It03) and 1991 1900 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 effort was only 553 fishing days (Fig. Year 2). Fishing effort data for 1948-83

JR. Y. Ito. 1992. Western Pacific ­ Figure 1.- Total annual skipjack tuna landings in metric tons (t) and pounds (lb) by the eries in 1991. U.S. Dep. Commer., NOAA, Natl. pole-and-line fishery in Hawaii, 1900-91. Sources: 1900-47 from Yamashita (1958); Mar. Fish. Serv., Southwest Fish. Sci. Cent., 1948-70 from Uchida (1976); 1970-83 from KikkawaI, 1984-85 from State of Hawaii Honolulu Lab., Southwest Fish. Sci. Cent. Division of Aquatic Resources; 1986-87 from Pooley4, and 1988-91 from It0 3 Admin. Rep. H-92-15, 38 p.

62 Marine Fisheries Review 3IXXJ 4 .".. Total 8000 ,....., 2500 ~ ,....., 3 ,....., 6000 ...... ,"0 2000 ~ ~ 1:: ...... ,~ ;g 1500 2 ...... ,a 4) ~ 4000 t>Il ~ ] 1000 ~ ~ ~ 2000 500

1950 1955 1960 1965 1970 1975 1980 1985 1990 1950 19S5 1960 1965 1970 1975 1980 1985 1990 Year Year

Figure 2.- Total annual fishing effort (in days) by the Figure 3.- Annual skipjack tuna CPUE in metric tons (t) and pole-and-line fishery in Hawaii, 1948-91. Effort data for pounds (lb) per vessel per day for all sizes (total) and large fish 1948-83 and 1986-87 are standardized (Uchida, 1976; (>6.8 kg or 151b), 1948-91. Sources as given in Figures I and 4. l Kikkawa ). Sources as given in Figure I.

(Uchida, 1976; Kikkawa 1) and for in 1972-73 the proportion of large fish the fleet also changed in the 1970's. At 1986-87 (POOley4) were standardized in Hawaii landings fell to a low of the height of the fishery in the 1950' s (Fig. 2) to account for zero-catch trips 40% in 1974 and remained below 40% and 1960' s, several vessels were based and relative efficiency (Class I versus through 1977 (Fig. 4). Reduced land­ on the islands of Hawaii and Maui, Class II). Data for 1984-85 and 1988-91 ings of large fish resulted in a substan­ and sizable catches came from the were summary statistics without the in­ tial decrease in profitability to the pole­ northeast coasts of these islands formation required for standardization. and-line fishery (Hudgins, 1987). The (Uchida, 1970). In the 1970'sand The importance of standardization was proportion of large fish in the catch 1980's most of the catch came from minimal after 1987 because the 1988-91 has shown an upward trend since 1977 areas around Oahu, Kauai, Molokai, data included zero-catch trips and con­ but has only exceeded 50% in a few and Lanai (Kikkawa'). Presently all of tained primarily Class II fishing days. years (1983, 1988, and 1991, Fig. 4). the vessels work out of Kewalo Basin Catch rates (CPUE in t1Class II fish­ The distribution of fishing effort by or Kaneohe Bay on Oahu. ing day) exhibited a declining trend in the 1970's and 1980's (Fig. 3). The high degree of interannual variability in CPUE was typical of geographically restricted surface fisheries for skipjack tuna, but the declining trend was un­ ~ 0.8 usual. In particular, the drop in CPUE 4) for large (>6.8 kg, >15 Ib) skipjack i.... 0.6 tuna in 1974 was extreme and was sus­ 0 tained though 1987 (Fig. 3). Large (>6.8 kg) skipjack tuna his­ .~ 0.4 torically represented over 50% of the ~ Hawaii landings by weight (Fig. 4). P:: 0.2 None of the world's major skipjack tuna fisheries depend on such large fish to supply the bulk of their catch. 1960 1965 1970 1975 1980 1985 1990 Large skipjack tuna command higher prices in both the fresh fish and can­ Year nery markets. From a high of over 80% Figure 4.- The proportion of large (>6.8 kg or 4S. G. Pooley. NMFS shore-side sampling pro­ 15 Ib) fish in annual skipjack tuna landings by gram. Honolulu Lab., Southwest Fish. Sci. the pole-and-line fishery in Hawaii, 1960-91. Cent., Nat!. Mar. Fish. Serv., NOAA, 2570 Dole Sources for size composition of catches: 1960-84 St., Honolulu, HI 96822-2396, un pub!. data. and 1986-87 from Poolel and 1988-91 from Ito3

55(2), 1993 63 Increasing age of the fishing fleet 450,000 Ib) per month after the can­ (catch per trip) for bait fish in the 1970­ and rising fuel prices may have con­ nery closed, reducing summer land­ 81 period (KikkawaI) averaged slightly tributed to more conservative fishing ings to about 54% of annual landings (ca. 4%) higher than in the previous practices in the 1970's and 1980's, re­ (1986-87 average, Pooley et aI. 6). decade (Uchida, 1977) but showed a sulting in fewer trips taken far from The decline of the Hawaiian domes­ declining trend. In 1986-88, bait fish land. In the 1970's skipjack tuna pole­ tic pole-and-line fishery roughly coin­ CPUE in Pearl Harbor averaged 27% and-line vessels also began to fish cided with increases in skipjack tuna lower than that in 1970-81 (Koba­ 7 around fish aggregating devices landings by the domestic troll fishery yashi ). These modest declines (1970­ (FAD's), in addition to the more tradi­ in Hawaii. The amount of skipjack tuna 81, 1981-86) in bait fish CPUE may tional practice of scouting for bird caught by domestic longline and have contributed to the problems of flocks to locate fish. If large skipjack handline fisheries in the Hawaii Ex­ the pole-and-line fishery but were not tuna were more common farther off­ clusive Economic Zone (EEZ) has al­ viewed by industry participants as a shore, a greater frequency of nearshore ways been relatively insubstantial, but direct cause for the decline of the fish­ trips might have contributed to the de­ commercial troll catches increased ery (Boggs and Pooley8, 1987). creased catch of large fish. Uchida and from <1 % of Hawaii's total skipjack A more serious problem for some Sumida (1971) found the average size tuna landings in the early 1970's to vessels has been the high cost of the of skipjack tuna caught by 7 vessels in 10% in 1985 and to about 20% in 1990 vessel insurance required for entering the summer of 1967 was smallest in and 1991. Expressed as a percentage, U.S. military areas (i.e., Pearl Harbor) areas closest to Oahu. this increase is partly due to the de­ to catch bait (Boggs and Pooley 8, Changes in the geographic distribu­ cline in pole-and-line landings, but troll 1987). Alternatives to the harvest of tion of fishing effort in the 1970's ap­ landings did increase from <50 t «0.1 wild bait by each individual vessel have pear to have affected overall CPUE, million pounds) in the early 1970's to been proposed (Shug and Shang9), but which was consistently higher than av­ >200 t (>0.5 million pounds) in 1991 Hawaii fishermen are very resistant to erage for oceanic areas, defined as more (Boggs and Ito, 1993). purchasing bait, especially when wild than 37 km (20 n.mi.) from shore Pole-and-line vessels from Japan bait is available. Under present condi­ (Uchida, 1966, 1970, 1976). The catch fishing for skipjack tuna within the EEZ tions, the rearing or importation of bait from oceanic areas averaged about 25% surrounding the Northwestern Hawai­ fish would be stop-gap measures and of the total catch from the 1950' s ian Islands also increased their catches would not be economically feasible through the early 1960' s (Uchida, during the decline of Hawaii's domes­ (Shug and Shang9). 1966). From 1974 to 80 catches from tic pole-and-line fishery. Foreign fish­ Fish Availability oceanic areas averaged only about 20% ing effort increased from 213 to 767 of the total catch (Kikkawa'). Data on vessel-days from 1972 to 1977, while Owing to the small scale of Hawaii's the distribution of the catch in more re­ foreign catch increased from 1,000 to skipjack tuna fishery, local fishing pres­ cent years have not been summarized. 4,600 t (Yong and Wetherall, 1980). sure is not likely to affect the avail­ The cannery closed in 1984 because From 1978 to 1984 the annual catch in ability of skipjack tuna in Hawaii. of economic restructuring in the glo­ the EEZ by the foreign fishery ranged Uchida (1976) showed that in Hawaii, bal tuna industry and because of mar­ from 2,000 to 4,000 t, reaching twice changes in CPUE were not associated ket constraints (King, 1987). The the level of the domestic catch (Boggs, with changes in local fishing intensity decline in Hawaii skipjack tuna land­ 1987). No foreign data have been ob­ at a time when the local catch was ings contributed to the problems of the tained since 1984, but this fishery con­ much higher than it has been in recent cannery but was not directly respon­ tinued to operate legally in the EEZ years. The increase in pole-and-line sible for its closure. This pivotal event through 1992. New regulations may catches by foreign vessels in the Ha­ left the fishery with only a local, fresh discourage the continuation of this fish­ waii EEZ in the 1970's roughly coin­ and market. Previously, the ery in 1993. fishery had been highly seasonal; sum­ 7D. R. Kobayashi. Honolulu Lab., Southwest mer (May-September) landings aver­ Causes for the Decline Fish. Sci. Cent., Natl. Mar. Fish. Serv., OAA, 2570 Dole St., Honolulu, HI 96822-2396, aged about 400 t (900,000 Ib) per month Bait Problems unpubl. data. accounting for about 70% of annual 8e. H. Boggs and S. G. Pooley. 1987. Strategic landings (1964-82 average, Hudgins5). A lack of bait during certain times planning for Hawaii's aku industry. U.S. Dep. of the year is frequently cited as a prob­ Commer., NOAA, Natl. Mar. Fish. Serv., South­ However, the fresh fish market ab­ west Fish. Cent., Honolulu Lab., Southwest sorbed only about 140-200 t (300,000­ lem by Hawaii fishermen. The CPUE Fish. Cent. Admin. Rep. H-87-1, 22 p. 9D. M. Shug and Y. e. Shang. 1983. An eco­ nomic feasibility study of culturing topmin­ 5L. L. Hudgins. 1986. Economic issues of the 6S. G. Pooley, S. Teramoto, and A. C. Todoki. nows as an alternative baitfish for skipjack tuna size distributions of fish caught in the Hawai­ 1988. Hawaii's aku boat fishery in 1986 and fisheries in Hawaii, American Samoa, Guam, ian skipjack tuna fishery 1964-82. U.S. Dep. 1987. U.S. Dep. Commer., NOAA, Natl. Mar. and the Northern Mariana Islands. Pacific Busi­ Commer., NOAA, Natl. Mar. Fish. Serv., South­ Fish. Serv., Southwest Fish. Cent., Honolulu ness Center, University of Hawaii, Honolulu, west Fish. Cent., Honolulu Lab., Southwest Fish. Lab., Southwest Fish. Cent. Admin. Rep. H­ HI 96822. Econ. Dev. Admin., Tech. Assist. Cent. Admin. Rep. H-86--14, 16 p. 88-16, 15 p. Proj. Rep., 32 p.

64 Marine Fisheries Review cided with the decline of Hawaii's pole­ crease could not correctly explain the needed for evaluation of fishery inter­ and-line fishery (Boggs, 1987), but decline in catches in Hawaii a year action (Hampton, In press). there was no significant correlation before (in 1974). Moreover, eastern Pa­ Annual time series of skipjack tuna between annual catch by the foreign cific catches subsequently declined catch in Hawaii have been found to be fishery in the EEZ and domestic CPUE (1983-90, IATIC, 1992) without a cor­ correlated with sea surface tempera­ (r = -0.34, P >0.25, N = 13) for years responding increase in Hawaii's CPUE ture (Jones 11) and salinity (Seckel, with available data (1972-84). (Kearney, 1987). Furthermore, CPUE 1972). Various models have been used More research is needed to establish in the eastern Pacific seems to be unaf­ to predict annual catches based on these whether the Pacific-wide increase in fected by harvest level (IATTC, 1992). environmental variables (Mendels­ catch from <500,000 t in 1980 to al­ If there was a negative impact of the sohn2; Boggs, 1988, 1989). The most most 900,000 t in 1990 (IATTC, 1992; eastern Pacific fishery on Hawaii's recent model based on sea surface tem­ Hampton, In press) has affected the fishery, it would most likely take ef­ perature (Boggs, 1988) explained 68% availability of skipjack tuna to Hawaii fect after a time lag to give eastern of the variation in the CPUE of large fishermen. The evidence suggests ma­ Pacific fish time to reach Hawaii and skipjack tuna during 1960-83 (Fig. 5). jor increases in catch have had no ef­ to grow to the size harvested by This model suggests that a sustained fect on relative abundance, as indicated Hawaii's fishery (Kearney, 1987). A decline in CPUE for large skipjack tuna by CPUE in large-scale fisheries. For significant (r =0.54, p <0.05, N =30 after 1973 was related to a sustained example, the largest catch and the years) negative correlation has been change in spring sea surface warming greatest increase in catch was in the found between the Hawaii catch of patterns east of Hawaii. western Pacific, where a doubling of skipjack tuna and the total catch (of all Spring warming patterns reflect the the catch from 1980 to 1990 had no sizes) in the eastern Pacific one year relative strength and northward extent perceptible impact on CPUE in that earlier (lanelli 10). However, a better of the California current extension region (Hampton, In press). Declining indicator of interaction between these (CCE) which joins the North Equato­ abundance might have been obscured fisheries would be a significant nega­ rial Current (NEe) near Hawaii. An by improvements in fishing efficiency tive correlation between CPUE (rather hypothesis is that the CCE and NEC that increase CPUE (Hampton, In than catch) in Hawaii and the eastern provide a conduit for immigration of press). However, tagging experiments Pacific catch in the preceding year. No large skipjack tuna from the eastern in the western Pacific also suggest that such correlation has been found tropical Pacific to Hawaii (Seckel, skipjack tuna are too productive to be (Kearney, 1987; Ianelli 1o). 1972; Boggs, 1988). The most recent affected by current levels of harvest The unusual dependence of Hawaii's models also involve a time lag (i.e., <1 million t). Kleiber et al. (1983) skipjack tuna fishery on large fish (Mendelssohn2; Boggs, 1988) which estimated a western Pacific biomass of means that it is more sensitive to could reflect relationships between skipjack tuna on the order of 3 million changes in fish population size struc­ temperature and recruitment, mortal­ t and a turnover rate of 6 million t/ ture than the large-scale fisheries of ity, or migration in preceding years. year. These studies (Kleiber et aI., the eastern and western Pacific. A re­ Previous models (e.g., Seckel, 1972) 1983; Hampton, In press) imply that duced size-frequency distribution of the explained variation in Hawaii CPUE the decline in Hawaii CPUE was not population due to increasing harvests based on the proximity of the north caused by a decline in the abundance by large-scale fisheries might not be edge of the CCE or NEC as measured of skipjack tuna in the western Pacific. reflected in the CPUE of those fisher­ by sea surface temperature and salin­ Some genetic evidence suggests that ies but still affect availability of large ity in Hawaii, but these models even­ skipjack tuna in Hawaii are part of a skipjack tuna in Hawaii (Boggs, 1987). tually failed to provide good central and eastern Pacific stock that is Eastern Pacific skipjack tuna size-fre­ predictions when the north edge of the partially isolated from the western Pa­ quency distributions show decreasing current passed north of the islands cific resource (Matsumoto et aI., 1984; average size from 1972 to 1981 fol­ (Skillman 12). Kearney, 1987). Tagging experiments lowed by increasing average size The spring warming model (Mendel­ in the eastern Pacific have resulted in through 1985 (IATTC, 1985, 1992). ssohn2; Boggs, 1988) was used to pre­ tag recoveries in Hawaii, whereas west­ This sequence does not correspond dict CPUE for large skipjack tuna ern Pacific tagging experiments have closely with Hawaii's abruptly reduced during 1984-90 and indicated that the not (Kearney, 1987). Therefore, the proportion of large fish in 1974, or the availability of large skipjack tuna decline in Hawaii's CPUE (Fig 4) increasing trend after 1977 (Fig. 4). might logically be attributed to a cor­ Further analyses of these data are be­ 11 E. C. Jones. A winter index of Hawaiian responding increase in eastern Pacific ing conducted (Ianelli10). In the west­ skipjack tuna catch. Honolulu Lab., Southwest 5 Fish. Sci. Cent., Natl. Mar. Fish. Serv., NOAA, skipjack tuna catches (Hudgins , 1987) ern Pacific, improved collection and 2570 Dole St., Honolulu, HI 96822-2396, which exceeded previous (1960-74) analysis of size-frequency data are unpubl. manuscr. levels in 1975 and remained higher 12 R. A. Skillman, Honolulu Lab., Southwest 10J. Ianelli, Fisheries Research Institute, Univ. Fish. Sci. Cent., Natl. Mar. Fish. Serv., NOAA, than average through 1982 (lATTC, Wash., Seallle, WA 98195. 1992, personal 2570 Dole St., Honolulu, HI 96822-2396. 1991, 1992). However, the timing of this in­ commun. personal commun.

55(2), 1993 65 the proportion of small fish in the catch 4 (Boggs and Pooley, 1987), but FAD - Predicted 8000 fishing seems to be mostly a last resort ,-... ~ when schools of larger fish cannot be .. Observed 3 :!2. i~ located. Small fish landings increased 6000 :S '-' '-' in 1976 whereas FAD's were not fully deployed until 1980 (Hudgins5, 1987). ~ 2 Declining profitability has played an 4000 ~ ;a ;a important role in the decline of the u u fishery (Pooley, 1987). Low earnings g 1 2000 since the 1960' s curtailed investment g in new boats. Attempts to increase prof­ its by selling more high-priced, fresh 1960 1965 1970 1975 1980 1985 1990 skipjack tuna faced market limitations even before the cannery closed. Dur­ Year ing 1970--85 the price per ton rose 45%, but costs rose 75% (after inflation). To Figure 5.- Annual skipjack tuna CPUE in metric tons (t) offset fuel (200%) and insurance and pounds (Ib) per vessel per day for large fish (>6.8 kg (390%) cost increases, the share of or 15 Ib), 1960-91, compared with CPUE predicted by an environmental model. Sources as given in Figures 1 and 4. profit paid to crews was kept low, and repairs were postponed (Pooley, 1987). Poor maintenance resulted in frequent breakdowns and safety problems. Five around Hawaii should have returned to duced by the impacts of fishing on vessels which sank during the 1980' s pre-1974 levels after 1983 (Fig. 5). population age structure (factor 3) but and 1990' s have not been replaced. Although the proportion of large fish further study is needed. Such problems may have influenced in the Hawaii catch returned to 1960­ Economic Causes of the Decline the fleet's fishing range, resulting in fewer 73 average levels in 1988 and 1991 fishing trips to more productive oceanic (Fig. 4), the CPUE for large skipjack One economic factor in the continu­ areas. Now, most of the vessels still re­ tuna in recent years has remained much ing decline in total catches after 1974 maining in the fleet are well maintained. lower than predicted (Fig. 5). (Fig. 1) was a negative correlation be­ An increase in troll, handline, and Three factors that may have contrib­ tween catch and the price of fuel longline landings of yellowfin and big­ uted to lower-than-predicted CPUE af­ (Hudgins5). In a comparison of catches eye tunas during the 1970's and 1980's ter 1983 were 1) a self-imposed quota for 1982 with those for 1974, the de­ resulted in competition for the fresh employed by vessels to avoid flooding crease in annual catch attributable to tuna market, reducing the available a limited market, 2) reduced scouting fuel price increases was estimated to market for skipjack tuna after the can­ and fishing closer to port, and 3) a have reduced annual revenue by $1.3 nery closed. Although skipjack tuna is change in the overall age structure of million. Over this same period, a de­ priced lower than (on the population because of increased crease in catch attributable to reduced average) and is appreciated by Hawaii fishing pressure elsewhere in the Pa­ CPUE and a low proportion of large residents in raw, cooked, and dried cific. The first two factors are eco­ fish in the catch (Fig. 4) were esti­ product forms, it is not widely accepted nomic, and could result in reduced mated to have reduced annual revenue in the local restaurant (tourist) or ex­ CPUE without any change in fish abun­ by $1.0 and $0.36 million, respectively port markets. In 1985 the average ex­ dance. For example, CPUE is biased (Hudgins5). These losses represent over vessel price for skipjack tuna was only downwards by a self-imposed quota 50% of potential revenue; actual rev­ $2.48/kg ($1.l3/1b), whereas the aver­ (factor 1) because measures of effort enue was only $2.5 million in 1982 age price for yellowfin tuna was 26% (days) and CPUE (catch per day) do (Pooley et aI. 6). higher. The price difference has in­ not account for trips of less than a day The mechanism by which fuel price creased along with prices, and in 1991 when a quota is achieved early in the increases affect the catch has not been the average yellowfin tuna price of day. Increased fishing near shore (fac­ documented, but the fuel price rise that $4.98/kg ($2.26/1b) was 58% higher tor 2) would decrease CPUE because began in 1973 did not immediately af­ than the average skipjack tuna price. average CPUE is highest >37 km from fect the total number of fishing days Yellowfin tuna can readily be sold to shore (Uchida, 1966, 1970, 1976) and (Fig. 2). Perhaps expensive fuel and the restaurant market in Hawaii or ex­ fish may be smaller than average near poor maintenance on some vessels re­ ported, and it has a much longer shelf shore (Uchida and Sumida, 1971). Ex­ sult in restricted scouting for schools life than skipjack tuna. Yellowfin and isting analyses do not indicate that the of fish and in fishing closer to land. are preferred over skip­ availability of large fish has been re­ Fishing around FAD's may increase jack tuna for in the export mar-

66 Marine Fisheries Review kets. Flash-frozen skipjack and yellow­ not recovered owing to continued high species. Expansion of the market will fin tuna imported to Hawaii from Ja­ costs, low profits, and a limited market. likely require innovative product tech­ pan also competes with the Hawaii nology that can economically preserve Remedies and Future Prospects fishery for a share of the local market. summer catches for later sale or fish­ The flash-frozen product is acceptable A workshop and a strategic plan­ ing technology that will permit in­ for sashimi, although it can be distin­ ning process (Boggs and Pooley8, creased catches during the season of guished from fresh skipjack tuna. 1987) were conducted in Honolulu in low availability. The closure of the Honolulu tuna 1986 to discuss causes of the fisheries In 1986 Hudgins (1987) predicted cannery in 1984 cost the skipjack tuna decline and remedial actions. An ex­ that without new markets, economic fishery an estimated $0.5 million (18%) panded market and products with a long competition would force all but 4 or 5 in annual sales, and the loss would shelf life to absorb peak production of the most efficient Hawaii skipjack have been much worse had the fishery during the summer were seen as the tuna fishing vessels out of business. not already been so reduced (Hudgins, most important objectives for revital­ She predicted that these vessels would 1987). The most pronounced effect of izing the fishery. A group of investors supply about 900 t (2 million Ib) of the the closure has been to discourage re­ purchased the cannery facility in 1985 skipjack tuna in the Hawaii fresh mar­ vitalization of the fishery. The lack of with the intention of integrating it into ket at prices of $2.75-3.85 per kg a cannery market is especially trouble­ a marine-oriented tourist center but the ($1.25-1.75/1b). These predictions are some during the summer when the skip­ cannery has not reopened. Making tuna almost exactly met by the number of jack and yellowfin tuna fisheries reach canning profitable in Hawaii would re­ vessels (6,4 full-time), landings (955 peak production. As a result, pole-and­ quire promotion of specialty packs that t, 2.1 million Ib), and average price line vessels occasionally experienced appeal to tourists and local residents, ($2.87/kg, $1.30/lb) for skipjack tuna severe market competition and devas­ because production of normal canned in 1991. Unless a larger market is de­ tating price reductions in the 1980' s tuna in Hawaii is too expensive to com­ veloped, there is no reason to expect (Boggs and Pooley, 1987). pete on the world market (King, 1987). much expansion of Hawaii's skipjack Self-imposed catch limits are now The available evidence indicates that tuna fishery in the near future. The­ employed by Hawaii pole-and-line ves­ the skipjack tuna population can easily pole-and-line fleet may continue to de­ sels to avoid flooding the limited fresh­ support an expanded fishery in Ha­ cline with age and the local market may fish market, especially on trips made waii, although the fishery would re­ increasingly be supplied by imports and during summer when fish are most main vulnerable to an environmentally by Hawaii's commercial troll fishery. available (Boggs, 1988, 1989). Incor­ driven reduction in availability like that poration of a monthly limit to landings of 1974-83. Ifocean-wide fishing pres­ Acknowledgments with an environmental model (Boggs, sure has had an impact on availability, We thank Shoji Teramoto and 1988) produced more realistic predic­ local (EEZ) management would not Russell Ito of the NMFS Honolulu tions of CPUE and annual catch substantially ameliorate that impact Laboratory for collecting the data on (Boggs, 1988, 1989). Since summer is because the local fishery is relatively catch, number of trips, and size com­ also the season when large fish pre­ small. Bait fish stocks would be the position of the catch for 1986-91. We dominate in the catch, self-imposed only resources that might require local also thank Sam Pooley, Richard quotas contribute to a lower propor­ management if the fishery were to ex­ Shomura, and Ray Sumida of the Ho­ tion of large fish on an annual basis. pand. These stocks were sufficient in nolulu Laboratory for helping to bring In summary, Hawaii's pole-and-line the 1970's to support three times the together the information needed for this fishery was economically stressed number of full-time vessels currently review. throughout the 1970' sand 1980's be­ active. The modest decline of bait fish cause of rising costs and reduced prof­ stocks (ca. 27%) since the 1970's might Literature Cited itability (Pooley, 1987). Then from become a limiting factor if the fishery Boggs, C . H. 1987. Review of biological re­ search on skipjack tuna. In Forces of change 1974-83 the availability of large fish were to more than double its present in Hawaii's aku (skipjack tuna) industry, declined because of environmental size. If the profitability of the fishery 1986 workshop summary, p. SO-56. U.S. changes (Mendelssohn2; Boggs, 1988) increased, it might be able to support a Dep. Commer., NOAA Tech. Memo. NMFS­ and the fishery declined. Models based SWFC-72. bait fish culture industry (Shug and __~ . 1988. Forecasting skipjack tuna on environmental factors predict in­ Shang9). availability in Hawaii. Southwest Fish. creased availability since 1983 but The future of the fishery depends Cent., Natl. Mar. Fish. Serv., La Jolla, CA 92038, Tuna Newsletter 91: 5-7. CPUE has remained low. Reasons for primarily on the development of mar­ _:-=-::-:-' 1989. Hawaii skipjack forecast for continuing low CPUE may include self­ kets. The State of Hawaii has conducted 1989 issued: Forecast predicts a catch rate imposed quotas and fishing closer to market expansion projects and sup­ of 2,200 large aku per boat, per day. South­ west Fish. Cent., Natl. Mar. Fish. Serv., La shore than in the past. No clear evi­ ported experiments to try and increase Jolla, CA 92038, Tuna Newsletter 94:4. dence indicates that overfishing has had product shelf life, but these have not _,.----:----;:;- and R. Y. Ito. 1993. Hawaii's pe­ lagic fisheries. Mar. Fish. Rev. 55(2):69-82. a negative impact in Hawaii or else­ been very successful, in comparison _--;-_ and S. G. Pooley. 1987. Forces of where in the Pacific. The fishery has with similar efforts in promoting other change in Hawaii's aku (skipjack tuna) in­

55(2), 1993 67 dustry, 1986 workshop summary. U.S. Dep. King, D. M. 1987. World tuna markets and the ment in the 90's and beyond. Part I. Fishery Commer., NOAA Tech. Memo. NMFS­ Pacific fishery. In Forces of change in and stock synopses, data needs, and man­ SWFC-72, 70 p. Hawaii's aku (skipjack tuna) industry, 1986 agement. Mar. Rec. Fish. 13:165-177. Natl. Forsbergh, E. D. 1980. Synopsis of biological workshop summary, p. 18-23. U.S. Dep. Coalition Mar. Conserv., Savannah, Geor­ data on the skipjack tuna, Katsuwonus Commer., NOAA Tech. Memo. NMFS­ gia. pelamis (Linnaeus, 1758), in the Pacific SWFC-72. __-,---;::- . In press. A brief review of biology ocean. In W.H. Bayliff, (Editor), Synopses Kleiber, P., A. W. Argue and R. E. Kearney. and fisheries for yellowfin tuna of biological data on eight species of 1983. Assessment of Pacific skipjack tuna albacares in the western and central Pacific scombrids, p. 295-360. Inter-Am. Trop. Tuna Katsuwonus pelamis resources by estimat­ Oceans. In R. S. Shomura, J. Majkowski and Comm., Spec. Rep. No.2. ing standing stock and components of popu­ S. Langi (Editors), Proceedings of the FAO Hampton, J. In press. A review of skipjack lation turnover from tagging data. Can. expert consultation on interactions of Pa­ fishery interaction in the western and cen­ J. Fish. Aquat. Sci. 44(6):1122-1134. cific tuna fisheries, Noumea, New Caledonia, tral Pacific Ocean. In R. S. Shomura, J. Matsumoto, W. M., R. A. Skillman, and A. E. 3-11 December 1991. Food & Agric. Or­ Majkowski, and S. Langi (Editors), Proceed­ Dizon. 1984. Synopsis of biological data on gan., U.N., FAO Fish. Tech. Pap. ings of the FAO expert consultation on in­ skipjack tuna Katsuwonus pelamis. U.S. Dep. Uchida. R. N. 1966. The skipjack tuna fishery teractions of Pacific tuna fisheries, Noumea, Commer., NOAA Tech. Rep. NMFS Circ. in Hawaii. In T. A. Manar (Editor), Proceed­ New Caledonia, 3-11 December 1991. Food 451,92 p. ings, governor's conference on central Pa­ & Agric. Organ., U.N., FAO Fish. Tech. Pap. Miyabe, N. In press. General review paper of cific fishery resources, Honolulu-Hilo, 28 Hudgins, L. L. 1987. Economic prospects for Pacific bigeye tuna Thunnus obesus. In R. S. February-12 March, 1966, p. 147-159. State Hawaii's skipjack tuna industry. In Forces Shomura, J. Majkowski and S. Langi (Edi­ of Hawaii, Honolulu. of change in Hawaii's aku (skipjack tuna) tors), Proceedings of the FAO expert con­ __-,---_. 1970. Distribution of fishing effort industry, 1986 workshop summary, p. 39­ sultation on interactions of Pacific tuna fish­ and catches of skipjack tuna, Katsuwonus 42. U.S. Dep. Commer., NOAA Tech. eries, Noumea, New Caledonia, 3-11 De­ pelamis, in Hawaiian waters, by quarters of Memo. NMFS-SWFC-72. cember 1991. Food & Agric. Organ., U.N., the year, 1948-65. U.S. Dep. Inter., Fish ___ and S. G. Pooley. 1987. Growth and FAO Fish. Tech. Pap. and Wildlife Serv., Bur. Commer. Fish., contraction of domestic fisheries: Hawaii's Pooley, S. G. 1987. Economic profile of Spec. Sci. Rep. Fish. 615, 37 p. tuna industry in the 1980's. In D. J. Doulman Hawaii's aku fleet. In Forces of change in _-;:--,----_. 1976. Reevaluation of fishing ef­ (Editor), Tuna issues and perspectives in the Hawaii's aku (skipjack tuna) industry, 1986 fort and apparent abundance in the Hawai­ Pacific islands region. East-West Center workshop summary, p. 31-37. U.S. Dep. ian fishery for skipjack tuna, Katsuwonus Press, Honolulu, Hawaii, 314 p. Commer., NOAA Tech. Memo. NMFS­ pelamis 1948-70. Fish Bull. 74:59-69. Hunter, J. R., B. J. Macewicz, and J. R. Sibert. SWFC-72. . 1977. The fishery for nehu, 1986. The spawning frequency of skipjack Seckel, G. R. 1972. Hawaiian-caught skipjack Stolephorus purpureus, a live bait used for tuna, Katsuwonus pelamis, from the South tuna and their physical environment. Fish. skipjack tuna, Katsuwonus pelamis, fishing Pacific. Fish. Bull. 84:895-903. Bull. 72:763-787. in Hawaii. In R. S. Shomura (Editor), Col­ IATTC. 1985. Annual report of the Inter-Ameri­ Sibert, J. 1987. The status of research on skip­ lection of tuna baitfish papers, p. 57-62. can Tropical Tuna Commission, 1984. jack tuna fisheries in the Pacific. In Forces U.S. Dep. Commer., NOAA Tech. Rep. IATTC, La Jolla, Calif., 270 p. of change in Hawaii's aku (skipjack tuna) NMFS Circ. 408. _....,-_-,- . 1992. Annual report of the Inter­ industry, 1986 workshop summary, p. 1-4. Uchida, R. N., and R. F. Sumida. 1971. Analy­ American Tropical Tuna Commission, 1990. U.S. Dep. Commer., NOAA Tech. Memo. sis of the operations of seven Hawaiian skip­ IATTC, La Jolla, Calif., 261 p. NMFS-SWFC-72. jack tuna fishing vessels, June-August 1967. June, F. C. 1951. Preliminary fisheries survey Skillman, R. A. 1987. Trends in Hawaii's aku U.S. Dep. Commer., NOAA Natl. Mar. Fish. of the Hawaiian-Line Islands area. Part III. production. In Forces of change in Hawaii's Serv., Spec. Sci. Rep. Fish. 629, 25 p. The live-bait skipjack fishery of the Hawai­ aku (skipjack tuna) industry, 1986 work­ Yamashita, D. T. 1958. Analysis of catch sta­ ian Islands. Commer. Fish. Rev. 13(2): shop summary, p. 28-31. U.S. Dep. tistics of the Hawaiian skipjack fishery. Fish. 1-18. Commer., NOAA Tech. Memo. NMFS­ Bull. 58: 253-278 Kearney, R. E. 1987. Skipjack tuna migration SWFC-72. Yong, M. Y. Y., and J. Wetherall. 1980. Esti­ and interactions. In Forces of change in Suzuki, Z. 1989. Catch and fishing effort rela­ mates of the catch and effort by foreign Hawaii's aku (skipjack tuna) industry, 1986 tionships for striped , blue marlin, and longliners and baitboats in the fishery con­ workshop summary, p. 4-13. U.S. Dep. black marlin in the Pacific Ocean, 1952­ servation zone of the central and western Commer., NOAA Tech. Memo. NMFS­ 1985. In R. H. Stroud (Editor), Planning the Pacific, 1955-77. U.S. Dep. Commer., NOAA SWFC-72. future of , research and manage­ Tech. Memo. NMFS-SWFC-2, 103 p.

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