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Workshop on the Management of Deepwater Artisanal and Small Scale Fisheries (continue)

Biological data and stock assessment methodologies for deep-slope bottomfish resources in the Hawaiian archipelago

R.B. Moffitt
2570 Dole Street, Honolulu, HI 96822, USA


Deep-slope bottomfish of the families Lutjanidae, Serranidae and Carangidae comprise a valuable small-scale fishery resource throughout the central and western Pacific. They have been commercially exploited in Hawaii for over 100 years with landings data collected by the State of Hawaii since 1948. The National Marine Fisheries Service Honolulu Laboratory and others have sporadically conducted biological research on these species since an increase in fishing activity in the Northwestern Hawaiian Islands (NWHI) started in the mid 1970s. In the late 1980s the Hawaiian Archipelago was divided into three management zones (Figure 1). The main Hawaiian Islands (MHI) zone surrounds the inhabited islands with most of the bottom-fishing habitat situated within state waters (to 3 nm from shoreline). The uninhabited northwestern Hawaiian Islands were split into two zones; the smaller Mau zone is situated closer to the MHI and the larger Ho’omalu zone extends beyond the Mau zone to the end of the archipelago. The NWHI zones are both currently federally-managed limited-entry zones with bottom-fish habitat predominantly in federal waters.

Map of Hawaiian Archipelago Bottomfish Management Zones



2.1 Species and distribution

Commercial landings in Hawaii are dominated by four species of eteline snapper, Pristipomoides filamentosus, Etelis coruscans, E. carbunculus, Aprion virescens and a single species of grouper, Epinephelus quernus. Several other species of eteline snapper and carangids of the genera Caranx, Pseudocaranx, and Carangoides are also caught. These species are generally found in patchy aggregations near high relief features at depths ranging from 100–400 m. Aprion virescens can also be found on the shallower flat areas of the banks at depths less than 40 m where they can be caught with trolling gear.

2.2 Reproduction

Examination of gonadosomatic index and histological staging of ova has shown that several species of snappers are serial spawners. They spawn several times over a protracted summer breeding season making annual fecundity estimates difficult to obtain (Kikkawa 1984, Everson and Kikkawa 1984, Everson, Williams and Ito 1989). Size at sexual maturity has been estimated for the major species of snapper (Table 1).

Table 1
Length at maturity (L50) for Hawaiian snapper species

SpeciesFork length (mm)Literature source
Pristipomoides filamentosus430Kikkawa 1984
Etelis coruscans610Everson et al.1989
Etelis carbunculus300Everson 1984
Aprion virescens470Everson et al. 1989

2.3 Larval and juvenile stages

Little is known about the larval and juvenile stages of Hawaiian bottomfish. Eteline snapper larvae have been collected in small numbers from samples collected in late summer and early fall (Clarke 1991). Newly settled juveniles of Epinephelus quernus, still retaining pelagic stage coloration, are taken in early summer in lobster traps. Otolith examination has revealed these approximately 25mm long fish to be about 50days of age at settling (NMFS unpublished data). On the other hand Pristipomoides filamentosus juveniles first appear on the bottom at 70–100 mm in length and an age of approximately 180 days (Moffitt and Parrish 1989). In both cases these juveniles are found in habitats very different from the adult habitat described above. The newly settled groupers are found on the bank flats at depths of 30–50 m, but the actual bottom type is not known. The largest concentration of snapper juveniles found to date occupies featureless sand and mud flats off Kaneohe Bay, Oahu, Hawaii at depths of 60–100 m (Moffitt and Parrish 1989). These snappers remain in this habitat for approximately six months, reaching lengths of about 200 mm, before moving out to more typical high-relief slope habitats.

2.4 Age and growth

Age and growth studies have been conducted on several species using otoliths and length-frequency information (Uchida, Ito and Uchiyama 1979, Uchida, Tagami and Uchiyama 1982, Ralston and Miyamoto 1983, Ralston and Kawamoto 1987, Morales-Nin and Ralston 1990, Smith and Kostlan 1991, DeMartini, Landgraf and Ralston 1994, Moffitt and Parrish 1996). Ageing tropical bottomfish can be challenging. Annual marks have not been identified on the otoliths of the Hawaiian snappers and groupers, so otolith aging has relied on enumeration of presumed daily increments. This is not only a time consuming process, but one that leads to uncertain results. Ralston and Miyamoto (1983) found that daily increments could be reliably enumerated in fish up to about three years of age. Aging older fish was unreliable due to episodic otolith deposition. Also, many otoliths display only intermittent areas of discernable increments within larger cloudy unreadable areas. Ralston and Williams (1988) developed an integration method of aging fish from these otoliths, but some question remains on the accuracy of resulting age estimates (Morales-Nin 1988).

Similarly, problems are encountered when attempting length-based ageing studies. We have not collected length data from our fisheries on an extensive or regular basis. The only size information we routinely collect is obtained from the fish markets, where we receive information on the number of individuals and total weight of species specific lots, which gives us an average weight of individuals from each lot sold. We do have some length data collected from sporadic research studies, but the small sample size collected, the extended breeding seasons, longevity and variable individual growth rates of our bottomfish species lead to few, if any, discernable modes in length frequency distributions that could be used for age and growth estimation. One of the most successful data sets we have is that for juvenile Pristipomoides filamentosus (Moffitt and Parrish 1996), but this data covers only a narrow size range for this species and does a poor job estimating L.

2.5 Mortality

Mortality estimates for many Hawaiian bottomfish species have been calculated using a length-based regression estimator of L and the ratio of total mortality (Z) to the growth coefficient (K) (Wetherall et al. 1987, Polovina 1987). When the length-frequency distribution is obtained from an unfished stock, total mortality equals natural mortality (M) and, with an independent estimate of K, natural mortality can be estimated from the Z/K ratio. Alternatively, natural mortality can be estimated using an empirical relationship with K such as that suggested by Ralston (1987) where M=-0.0666 +2.52 K. Since both methods use an estimate of K to calculate M, the resulting estimate of M is only as accurate as the value of K used, and, as mentioned above, we are not confident that we have reliable estimates of K.

Table 2
Range of estimates of L, K, and M for the major Hawaiian bottomfish species

Pristipomoides filamentosus664–971 mm0.146–0.310.250–0.715
Etelis coruscans894–957 mm0.137–0.1430.278–0.360
Etelis carbunculus639–1 183 mm0.064 -0.1900.16–0.61
Aprion virescens1 165 mm0.120.236–0.241
Epinephelus quernus1 080–1 186 mm0.119–0.1260.233–0.253


The Western Pacific Regional Fishery Management Council (WPRFMC) has produced an annual report on the Hawaiian bottomfish fishery since the adoption of the Bottomfish and Seamount Groundfish Fishery Management Plan (Bottomfish FMP) in 1986. Assessment of the status of the stocks has relied on the long-term landing data collected by the State of Hawaii, which extends back to 1948. In 1990 an amendment to the Bottomfish FMP established procedures whereby bottomfish stocks were considered healthy as long as their spawning potential ratio (SPR) remained above 0.20. If, however, the SPR for any species dropped below the 0.20 level it would be considered recruitment overfished and the WPRFMC was mandated to develop and adopt management measures that would increase the SPR value to above the 0.20 overfishing threshold level. Somerton and Kobayashi (1990) developed a simple method of calculating SPR requiring input data of catch per unit effort (CPUE) and the percentage of mature individuals by weight in the catch. SPR is estimated as the ratio of the product of current CPUEand percent mature values to that of the unfished stock, estimated as the average of the CPUEand percent mature for the first few years of the fishery, i.e.

Using this definition of overfishing, no species of bottomfish in the Hawaiian archipelago has been overfished to date (WPRFMC 2002). However, when SPR estimates are calculated for the main Hawaiian Islands alone, rather than the archipelago as a whole, values for both Etelis species are well below the 20 percent threshold, indicating local depletion.

Changes in fisheries management legislation in the Magnuson-Stevens Fishery Conservation and Management Act of 1996 required modification of all United States fishery management plans. Following published guidelines (Restrepo et al. 1998) a new definition of overfishing was developed for the Bottomfish FMP (Moffitt and Kobayashi 2000, WPRFMC 2002). Future assessments, starting with the 2003 annual report, will use these definitions. The new rules establish a minimum stock size threshold (MSST) expressed as a fraction of biomass at maximum sustainable yield (BMSY) and a maximum fishing mortality threshold (MFMT) tied to the fishing mortality experienced at MSY (FMSY). When stocks fall below the MSST, they are considered overfished requiring adoption of management measures that will allow rebuilding of the stock. When fishing mortality rises above MFMT, overfishing is occurring and management measures must be adopted to reduce fishing mortality. The thresholds, relative to a ratio of current biomass (Bcurrent) and fishing mortality (Fcurrent) to BMSY and FMSY, respectively, are incorporated into a management control rule (Figure 2). Proxies for fishing mortality and biomass may be used in situations where direct measurements are not available. For deepslope bottomfish resources in the Hawaiian Archipelago, we use fishing effort (E) as a proxy for fishing mortality and CPUEas a proxy for biomass. Estimates of CPUEand Eat MSY (CPUEMSY, EMSY) are used as proxies for the reference points in calculating MSST and MFMT. Warning thresholds are incorporated into the control rule as a precautionary measure to reduce the chances of overfishing (i.e. BFlagand FOY). When no information on MSY is available thresholds cannot be establish using the above methods. In these situations a time series of CPUEand effort data can be used to establish reference and threshold values until better data becomes available (Figure 3).

MSY and target control rules for bottomfish stock complexes


With the difficulties involved in obtaining information on adequate MSY, CPUE and E for individual species within the bottomfish complex, we are applying the above method to the multispecies stock as a whole. To ensure the health of all component species within the multi-species stock, we are continuing to monitor SPR for individual species and, as in the past, require adoption of management measures whenever any species-specific SPR drops below the recruitment overfishing threshold of 20 percent (Moffitt and Kobayashi 2000, WPRFMC 2002).

To date a few estimates of Hawaiian bottomfish MSY have been suggested. Ralston and Polovina (1982) applied an equilibrium Schaefer surplus production model to commercial catch per unit effort (CPUE) data from a portion of the Main Hawaiian Islands resulting in an estimate of catchability and MSY of 272 kg per nautical mile of 100 fathom isobath. This value can then be applied to the rest of the Hawaiian chain using the length of the 100 fathom isobath for the entire archipelago to obtain an archipelago-wide MSY estimate of 606 t (335 t for the NWHI). However, the use of an equilibrium model and the need to estimate a large number of parameters, increases the uncertainty of these estimates.

Use of a time series of CPUEto establish a MSY reference


Kobayashi (1996) applied a dynamic production model using independent estimates of catchability obtained from Leslie model depletion studies conducted on isolated fishing areas in the Commonwealth of the Northern Mariana Islands and American Samoa to reduce the number of parameters and uncertainty. These estimates of catchability, in conjunction with CPUEdata from the NWHI bottomfish fleet, were used to estimate carrying capacity, MSY, CPUEMSYand EMSYfor the two bottomfish management zones in the NWHI. There is some concern on the appropriateness of using catchability estimates obtained from outside the study area, but the model does appear to fit the data fairly well. The resulting value constitutes the best available estimate of MSY to date of 266 t for the NWHI ( approximately 216 kg per nautical mile of 100 fathom isobath).


Even with all the research and data collection on Hawaiian bottomfish, we still must consider our situation to be “data poor”. Although we have some life history data for several species, most parameters for any one species remain ill defined with estimates varying widely between studies and techniques applied. Because of a suboptimal fishery-independent survey program we are forced to rely solely on commercial landings and sales reports for annual assessment data. There are several major concerns with relying on this fishery dependent data. First of all, we do not have a good idea of total landings in Hawaii. Reports from the commercial fishers and fish buyers give us a good idea of the commercial landings. There may be some under reporting, but it is not thought to be a major problem. What is a major problem is the lack of data on the recreational and subsistence components of the catch. These landings are not apt to be large in the remote uninhabited NWHI, but are certainly a major concern in the MHI where over 3000 vessels are registered and are potential bottomfishers. It will be difficult to manage a fishery based on MSY when we do not have an accurate measure of landings.

The use of commercial CPUEdata is also an area for concern. In order for a long time series of CPUEdata to be useful in an assessment, it must be related to resource abundance in a consistent manner. In other words, the catchability coefficient needs to be consistent. In Hawaii several technological advances over the years have made fishing easier, e.g. power-assisted reels, fish finders and global positioning systems (GPS). These advances have undoubtedly changed the relationship between CPUE and abundance for Hawaiian bottomfish resources. Unfortunately, we do not have information on when the various vessels (or fleets) started using any of this equipment and we don’t know how great an influence any one of these has on the catchability coefficient. Obviously, standardization of CPUEover time is required. Similarly, standardization of CPUEbetween vessels in the same fleet is needed. Each vessel has its own ability to catch fish or fishing power. This may be related to size of the vessel, on board equipment, crew ability, etc. In small fisheries, such as the NWHI bottomfish fishery, entry or exit of individual vessels from the fleet may alter the fleet-wide fishing power and subsequent relationship between reported fleet-wide CPUEand stock abundance. In a larger fleet, such as that found in the MHI, this relationship is less likely to change significantly with entry or exit of only a few individual vessels.

Accurate recording of effort is also important and is not always as straight forward as it seems. In our case we have commercial landings data collected by the State of Hawaii starting from 1948. Unfortunately, when the data collection program was started, the interest was solely economic, i.e. pounds landed and prices paid. To use these data in assessments, we have had to try to attach units of effort to the recorded catches. The best we were able to approximate was the catch-per-trip for individual vessels with no information on trip length or any possible changes in average trip duration over time. More recently we have required the commercial fishers to supply considerably more data on effort. Now we collect information on a daily basis including the number of hours, lines and hooks spent bottomfishing and trolling and the number of hours spent searching for bottomfishing sites. Both hours spent searching and hours spent actually fishing are important information for use in making good CPUEcalculations.

Another problem we have with fishing effort is our inability to allocate the effort between various species making stock assessments of particular species impossible. If fishers could target particular species exclusively, and we knew how much time was spent fishing for each individual species, we could assess the stocks of the individual species separately. In real life, however, the ability to target single species is incomplete with several species being caught at the same place, often on the same line. Also, on longer trips, fishers will purposely target a variety species in order to maximize the price received for the catch.

Finally, the establishment of restricted fishing areas (RFAs) and other marine protected areas (MPAs) has confounded the use of commercial CPUEas an indicator of stock abundance. This is not to say that MPAs are a bad idea. Their use to improve stock abundance and recruitment to the fishery should certainly be investigated. The concentration of fishing effort resulting from their presence, however, does change the relationship between commercial CPUEand stock abundance in an unknown manner. Without some sort of correction, assessments based solely on CPUEwould likely under-represent actual stock abundance.

In conclusion, the importance of collecting detailed and consistent catch and effort data from the beginning of a fishery cannot be over-emphasized. Our stock assessment methods rely on comparisons of current stock abundance to that of the unfished stock. Although our estimates of current CPUE, and therefore relative abundance, are adequate, we lack equally reliable estimates of initial CPUEto reflect unfished stock abundance.


Clarke, T.A. 1991. Larvae of nearshore fishes in oceanic waters near Oahu. U.S. Department of Commerce, NOAA Technical Report. NMFS 101. 19 pp.

DeMartini, E.E., K.C. Landgraf & S. Ralston 1994. A recharacterization of the age-length and growth relationships of Hawaiian snapper, Pristipomoides filamentosus. U.S. Department of Commerce, NOAA Technical Memorandum. NOAA-TM-NMFS-SWFSC-199.

Everson, A.R. 1984. Spawning and gonadal maturation of the ehu, Etelis carunculus, in the Northwestern Hawaiian Islands. In R.W. Grigg and K.Y. Tanoue (eds), Proc. 2nd Symp. Res. Invest. NWHI, Vol. 2, May 25–27, 1983, Univ. Hawaii, Honolulu, p. 128–148. UHIHI-SEAGRANT-MR-84-01.

Everson, A.R., H.A. Williams & B.M. Ito 1989. Maturation and reproduction in two Hawaiian eteline snappers, uku, Aprion virescens, and onaga, Etelis coruscans. Fishery Bulletin, U.S. 87:877–888.

Kikkawa, B.S. 1984. Maturation, spawning, and fecundity of opakapaka, Pristipomoides filamentosus, in the Northwestern Hawaiian Islands. In R.W. Grigg and K.Y. Tanoue (eds), Proc. 2nd Symp. Res. Invest. NWHI, Vol. 2, May 25–27, 1983, Univ. Hawaii, Honolulu, p. 149–160. UHIHI-SEAGRANT-MR-84-01.

Kobayashi, D.R. 1996. An update of maximum sustainable yield for the bottomfish fishery in the Northwestern Hawaiian Islands. Report to the Western Pacific Regional Fishery Management Council, Honolulu.

Moffitt, R.B. & D.R. Kobayashi. 2000. Recommended overfishing definitions and control rules for the Western Pacific Regional Fishery Management Council’s Bottomfish and Seamount Groundfish Fishery Management Plan. Administrative Report H-00-03, NMFS Southwest Fisheries Science Center-Honolulu Laboratory, Honolulu.

Moffitt, R.B. & F.A. Parrish 1996. Habitat and life history of juvenile Hawaiian pink snapper, Pristipomoides filamentosus. Pacific Science. 50(4):371–381.

Morales-Nin, B. 1988. Caution in the use of daily increments for ageing tropical fishes. Fishbyte. 6(August 1988).

Morales-Nin, B. & S. Ralston. 1990. Age and growth of Lutjanus kasmira (Forskal) in Hawaiian waters. Journal of Fish Biology. 36:191–203.

Polovina, J.J. 1987. Assessment and management of deepwater bottom fishes in Hawaii and the Marianas. In Tropical Snappers and Groupers: Biology and Fisheries Management, (J.J.Polovina and S. Ralston, eds.), pp. 505–532. Westview Press, Boulder Colorado, 659pp.

Ralston, S. 1987. Mortality rates of snappers and groupers. In Tropical Snappers and Groupers: Biology and Fisheries Management, (J. J. Polovina and S. Ralston, eds.), pp.375–404. Westview Press, Boulder Colorado, 659 pp.

Ralston, S. & K. Kawamoto 1987. An assessment and description of the status of bottom fish stocks in Hawaii. Southwest Fisheries Center, Administrative Report. H-87-7.

Ralston, S. & G.T. Miyamoto 1983. Analyzing the width of daily otolith increments to age the Hawaiian snapper, Pristipomoides filamentosus. Fishery Bulletin, U.S. 81:523–535.

Ralston, S. & J.J. Polovina 1982. A multispecies analysis of the commercial deep-sea handline fishery in Hawaii. Fishery Bulletin, U.S. 80:435–448.

Ralston, S. & H.A. Williams. 1988. Numerical integration of daily growth increments: an efficient means of ageing tropical fishes for stock assessment. Fishery Bulletin, U.S. 87:1–16.

Restrepo, V.R., G.G. Thompson, P.M. Mace, W.L. Gabriel, L.L. Low, A.D. MacCall, R.D. Methot, J.E. Powers, B.L. Taylor, P.R. Wade & J.F. Witzig 1998. Technical guidance on the use of precautionary approaches to implementing National Standard 1 of the Magnuson-Stevens Fishery Conservation and Management Act. NOAA Technical Memorandum, NMFS-F/SPO-31, NOAA/NMFS, Washington, DC.

Smith, M.K. & E. Kostlan 1991. Estimates of age and growth of ehu Etelis carbunculus in four regions of the Pacific from density of daily increments in otoliths. Fishery Bulletin, U.S. 89:461–472.

Somerton, D.A. &D.R. Kobayashi 1990. A measure of overfishing and its application on Hawaiian bottomfishes. Southwest Fisheries Center, Administrative Report. H-90-10.

Uchida, R.N., B.M. Ito & J.H. Uchiyama 1979. Survey of bottom fish resource in the Northwestern Hawaiian Islands. Southwest Fisheries Center, Administrative Report. H-79-20.

Uchida, R.N., D.T. Tagami & J.H. Uchiyama 1982. Results of bottom fish research in the northwestern Hawaiian Islands. Southwest Fisheries Center, Administrative Report. H-82-10.

Western Pacific Regional Fishery Management Council 2002. Magnuson-Stevens Act definitions and required provisions, Overfishing provisions. Western Pacific Regional Fishery Management Council, Honolulu.

Western Pacific Regional Fishery Management Council 2002. Bottomfish and seamount groundfish fisheries of the Western Pacific Region, 2001 Annual Report.

Wetherall, J.A., J.J. Polovina & S. Ralston 1987. Estimating growth and mortality in steady state fish stocks from length-frequency data. In Length-based Methods in Fishery Research (D. Pauly and G.R. Morgan, eds.), pp. 53–74. ICLARM Conference Proceedings 13.

Management of the northwestern Hawaiian islands deep-slope bottomfish and seamount groundfish resources

M. Mitsuyasu
Western Pacific Fishery Management Council
1164 Bishop Street, Suite 1400
Honolulu, Hawaii, USA 96813


The Hawaii deep-slope demersal fishery targets species of eteline snappers, carangids and a single species of grouper at depths ranging from 30–150 fm (60–300 m). The fishery is divided into two primary geographical areas: the inhabited main Hawaiian Islands (MHI) with their surrounding reefs and offshore banks; and the Northwestern Hawaiian Islands (NWHI), a chain of largely uninhabited islets, reefs and shoals extending 1200 nm across the North Pacific. For management purposes the NWHI fishery has been separated into the Mau Zone (between 161o 20' W longitude and 165oW longitude), closer to the MHI, and the Hoomalu Zone (west of 165 oW longitude) (Figure 1). A limited access programme has been established for each zone in addition to logbook reporting, vessel size limitations, observer coverage and other requirements.

Hawaiian archipelago bottomfish management zones


In addition to the deep-slope fisheries in the MHI and NWHI, there is potential for a seamount groundfish fishery in the northern most extent of the Hawaiian archipelago. A trawl and bottom longline fishery targeting alfonsino (Beryx splendens) and armourhead (Pseudopentaceros richardsoni) at the southeast Hancock Seamount in the NWHI was started by Russian and Japanese fishing vessels in the late 1960s (Okamoto 1982).

This paper discusses the management authority and process by which bottomfish resources are managed in the US Western Pacific region (Figure 2) and reviews the fishery characteristics and history of utilization of the NWHI bottomfish fishery. The development of management strategies and resulting regulatory regime is presented and the paper examines present management issues and future challenges for fishery managers.

United States Western Pacific Region



2.1 Authorities

In 1976 the United States Congress passed the Magnuson Fishery Conservation and Management Act, which established eight quasi-federal regional councils to manage fisheries in the exclusive economic zone (EEZ) surrounding the United States. Under this act, subsequently reauthorized as the Magnuson-Stevens Fishery Conservation and Management Act, the Western Pacific Council is the policy-making organization for the management of fisheries in the 200 nm EEZ adjacent to the Territory of American Samoa, Territory of Guam, State of Hawaii, the Commonwealth of the Northern Mariana Islands and the US Pacific island possessions of Jarvis, Johnston, Wake, Howland and Baker Islands, Kingman Reef and Palmyra and Midway Atolls. The inner boundary of the fishery management area is a line coterminous with the seaward boundaries of the state and territorial waters (the “3 mile-limit”). This area of 1.5 million nm2is the largest management area of the USregional fishery management councils and comprises about half of the total EEZ waters under USjurisdiction.

The main task of the Council is to protect fishery resources while maintaining opportunities for domestic fishing at sustainable levels of effort and yield. The Council manages and monitors fisheries throughout its region by developing and implementing fishery management plans. Plans are developed in compliance with National Standards (see following box) and scientific requirements of the Magnuson-Stevens Act, along with consideration of the social, cultural and economic values and realities of island communities.

Magnuson-Stevens Act National Standards
(1) Conservation and management measures shall prevent overfishing while achieving, on a continuing basis, the optimum yield from each fishery for the United States fishing industry.
(2) Conservation and management measures shall be based upon the best scientific information available.
(3) To the extent practicable, an individual stock of fish shall be managed as a units throughout its range, and interrelated stocks of fish shall be managed as a unit or in close coordination.
(4) Conservation and management measures shall not discriminate between residents of different states. If it becomes necessary to allocate or assign fishing privileges among various United States fishermen, such allocation shall be (A) fair and equitable to all such fishermen; (B)reasonably calculated to promote conservation; and (C) carried out in such manner that no particular individual, corporation, or other entity acquires an excessive share of such privileges.
(5) Conservation and management measures shall, where practicable, consider efficiency in the utilization of fishery resources; except that no such measure shall have economic allocation as its sole purpose.
(6) Conservation and management measures shall take into account and allow for variations among, and contingencies in, fisheries, fishery resources, and catches.
(7) Conservation and management measures shall, where practicable, minimize costs and avoid unnecessary duplication.
(8) Conservation and management measures shall, consistent with the conservation requirements of this Act (including the prevention of overfishing and rebuilding of overfished stocks), take into account the importance of fishery resources to fishing communities in order to (A) provide for the sustained participation of such communities, and (B) to the extent practicable, minimize adverse economic impacts on such communities.
(9) Conservation and management measures shall, to the extent practicable, (A) minimize bycatch and (B) to the extent bycatch cannot be avoided, minimize the mortality of such bycatch.
(10) Conservation and management measures shall, to the extent practicable, promote the safety of human life at sea

2.2 Management process

Management of fishery resources in the US is based on a “bottom-up”or “grassroots”approach to the development of fishery policy. The 16 members of the Western Pacific Council include representatives from the fishing community and state and federal governmental officials responsible for managing and conserving fishery resources in the Western Pacific Region. Half of the Council members are appointed by the US Secretary of Commerce from people nominated by their respective island governors. Other members represent government agencies that are responsible for fisheries, including the US National Marine Fisheries Service (NMFS), US Fish and Wildlife Service, the US Coast Guard and the State Department. Meetings of the Council are held throughout its jurisdiction.

The process for creating and implementing fishery management plans (FMPs) is dynamic and continuous. Development of these plans, or amendments, involve a systematic assessment of present conditions; identification of management alternatives and regulatory actions; evaluation of the likely environmental, biological, economic and social effects of the management alternatives; and estimation of future conditions if no action is taken. The Council currently has five multi-species FMPs - Pelagics, Bottomfish and Seamount Groundfish, Crustaceans, Precious Corals and most recently the Plan for Coral Reef Ecosystems.

The management process is transparent and open to the public at every decision step. As part of decision making, the Council receives advice from advisory bodies, federal agencies, state fisheries agencies, non-profit organizations and the general public. Citizen appointments on four Advisory Panels (Commercial, Recreational, Subsistence and Indigenous, and Ecosystem and Habitat) represent broad geographic areas and diverse cultures. Advisory Panel membership reflects different segments of the fishing community including processing, marketing, commercial, recreational and subsistence fishing, environmental organizations, researchers and other related sectors.

Plan Teams are established for each fishery management plan and consist of federal and state fishery managers, scientist and academics. The primary responsibility of each team is to assist in development of FMPs or amendments, annually review the status of fishery and provide recommendations to the Council for improvements to the management regime. A Scientific and Statistical Committee reviews proposed management actions and provides expert scientific advice to the Council.

2.3 Monitoring and reporting

Annual reports and evaluations are a critical part of each FMP as they ensure the need for change is identified systematically. Each FMP provides a basis for cooperation between NMFS, local agencies, and other organizations to collect and analyze data from the fisheries through an established monitoring programme. Fisheries are evaluated each year by the Council’s Plan Teams, which produce annual reports for each FMP and, or other reports addressing special problems within specific fisheries. Evaluations are based on Council programme principles and objectives. Recommendations are formulated, which are then reviewed by the Council and its advisory bodies, including the Scientific and Statistical Committee. Priorities are assigned based on the need for information and research to complete FMPs or amendments in support of the Council’s overall mission. Reports also identify research and data analysis needs, which can be used as a basis for short-and long-term programme planning by the NMFS and other agencies or organizations. The Council’s annual reports satisfy the national standard requirement for a Stock Assessment and Fishery Evaluation (SAFE). Report recommendations also provide a reference for the Council to request programme funds so that high-priority research and data needs will be met rapidly.

2.4 Overview of the Bottomfish and Seamount Groundfish FMP and amendments

In addition to Magnuson-Stevens Act policies, the Council established objectives for managing bottomfish resources in the Western Pacific Region through promulgation of the FMP. These objectives are to:

The Bottomfish and Seamount Groundfish Fishery Management Plan (Bottomfish FMP) was implemented in 1986. It prohibits certain destructive fishing techniques, including explosives, poisons, trawl nets and bottom-set gillnets. It established a moratorium on the commercial harvest of seamount groundfish stocks at the Hancock Seamounts and implements a permit system for fishing for bottomfish in the EEZ around the NWHI. The moratorium on the harvest of alfonsino and armourhead on the Hancock Seamounts, the only exploitable seamount habitat in the management area, was put in place (63 FR 35162, 29 June 1998) in an effort to rebuild the groundfish stocks. The moratorium will remain in effect until August 2010. The plan also established a management framework process that includes adjustments such as catch limits, size limits, area or seasonal closures, fishing effort limitation, fishing gear restrictions, access limitation, permit and, or, catch reporting requirements and a rules-related notice system.

NWHI Regulatory Regime

The FMP has been amended seven times since 1986. Amendment 1 was implemented in 1987 and put in place, within the framework structure of the FMP, the ability to rapidly implement limited access programmes for bottomfish fisheries in the EEZ surrounding American Samoa and Guam if required. Amendment 2 in 1988 divided the EEZ around the NWHI into two management zones: the Hoomalu Zone to the northwest and the Mau Zone to the southeast. A limited access system was created for the Hoomalu Zone while the Mau Zone remained open through general permitting. Amendment 3 (1991) defined recruitment overfishing as a condition in which the ratio of the spawning stock biomass per recruit at the current level of fishing to the spawning stock biomass per recruit that would occur in the absence of fishing is equal to, or less than, 20 percent. Amendment 3 also delineates the process by which overfishing is monitored and evaluated. Amendment4 (1990) requires vessel owners or operators to notify NMFS at least 72 hours before leaving port if they intend to fish in a 50 nm “protected species study zone”around the NWHI. This notification allows federal observers to be placed on board bottomfish vessels to record interactions with protected species if this action is deemed necessary. Amendment 5 (1999) established a limited access system for the Mau Zone. Amendment 6 (1999) identifies and describes essential fish habitat for managed species of bottomfish, discusses measures to minimize bycatch and bycatch mortality in the bottomfish fishery, provides criteria for identifying when overfishing has occurred in the fishery and describes fishing communities in the Council’s Region. Amendment 6 was only partially approved. The provisions for bycatch, overfishing and fishing communities in Hawaii were disapproved. The disapproved provisions were revised and implemented through Amendment 7 in August 2003. Amendment 7 established new control rules to monitor for “overfished”and “overfishing”conditions of resources managed under the Council’s FMPs. The new biomass based rules replaced the Spawning Potential Ratio (SPR) proxy which was implemented through Amendment 3.


3.1 Bottomfish management unit species

The Bottomfish FMP includes deep and shallow-water species found in Hawaii, American Samoa, Guam, the Northern Mariana Islands and other uninhabited US Pacific Islands. Bottomfish management unit species (BMUS) refer to the fishes listed in Table 1.

Table 1
Bottomfish management unit species

Common nameLocal nameScientific name
Silver jaw jobfishLehi (H); palu-gustusilvia (S)Aphareus rutilans
Grey jobfishUku (H); asoama (S)Aprion virescens
Squirrelfish snapperEhu (H); palu-malau (S)Etelis carbunculus
Longtail snapperOnaga, ulaula (H); palu-loa (S)Etelis coruscans
Blue stripe snapperTaape (H); savane (S); funai (G)Lutjanus kasmira
Yellowtail snapperPalu-I lusama (S); yellowtail, kalekale (H)Pristipomoides auricilla
Pink snapperOpakapaka (H); palu-tlenalena (S); gadao (G)Pristipomoides filamentosus
Yelloweye snapperPalusina (S); yelloweye Opakapaka, kalekale (H)Pristipomoides flavipinnis
SnapperKalekale (H )Pristipomoides sieboldii
SnapperGindai (H, G): palu-sega (S)Pristipomoides zonatus
Giant trevallyWhite ulua (H); tarakito (G); sapo-anae (S)Caranx ignoblis
Black jackBlack ulua (H); tarakito (G); tafauli (S)Caranx lugubris
Thick lipped trevallyPig ulua, butaguchi (H)Pseudocaranx dentex
AmberjackKohala (H)Seriola dumerili
Blacktip grouperFausi (S); gadau (G)Epinephelus fasciatus
Sea bassHapuupuu (H)Epinephelus quernus
Lunartail grouperPapa (S)Variola louti
Emperor fishes:  
Ambon emperorFiloa-gutumumu (S)Lethrinus amboinensis
Redgill emperorFiloa-paloomumu (S); mafuti (G)Lethrinus rubrioperculatus
Seamount groundfish:  
Alfonsin Beryx splendens
Ratfish/butterfish Hyperoglyphe japonica
Armourhead Pseudopentaceros richardsoni

G: Guam,
H: Hawaii,
S: American Samoa.

3.2 Life history

Relatively little is known about the reproduction and early life history of deepwater bottomfish in the region. Spawning occurs over a protracted period and peaks from July to September (Haight, Kobayshi and Kawamoto 1993). The eggs are released directly into the water column and hatch in three to four days. The planktonic larval phase is thought to last at least 25 days (Leis 1987). For some species this phase may be considerably longer. For example, the pelagic stage for opakapaka is thought to be as long as six months (Moffitt and Parish 1996). Larval advection simulation research indicates that larval exchange may occur throughout the Hawaiian archipelago and that the amount of larval exchange between the NWHI and the MHI is correlated with the duration of the larval phase, the highest larval exchange occurring with the longest larval phase durations (Kobayashi 1998). Data on actual exchange rates, however, are lacking. Preliminary genetic work on onaga and ehu corroborates the notion of single archipelago-wide stocks of bottomfish. However, more recent genetic work on hapuupuu suggests that more localized stocks of this endemic species may exist within the Hawaiian archipelago.

Little is known of the life history of the juvenile fish after they settle out of the plankton, but research indicates that P. filamentosus juveniles utilize nursery grounds well away from the adult habitat (Parish 1989). Most of the target species have a relatively high age at maturity, long life span, and slow growth rates. These factors, combined with considerable variation in larval recruitment make them highly susceptible to overfishing (Haight et al. 1993).

Robert Humphreys, Pacific islands Region Science Center, National Marine Fisheries Service, reports that armourhead undergo an initial 2+ year pre-recruit pelagic phase in surface waters of the temperate and subarctic North Pacific. During this pelagic phase, armourhead undergo somatic growth but remain non-reproductive. Armourhead return to the southern Emperor-northern Hawaiian Ridge (SE-NHR) seamounts (consisting of Koko, Yuryaku, North and South Kammu, Colahan, and C-H Seamounts outside the US EEZ and Northwest and Southeast Hancock Seamounts inside the US EEZ) and recruit to the summits and upper slopes of these seamounts. Recruitment to the bottom trawl fishery and to the seamounts are simultaneous; these full-size adults recruit to the seamounts primarily during late spring-early summer. After recruitment, armourhead cease somatic growth, develop reproductively and spawn annually at the seamounts during November–February. Post-recruit movement of armourhead between seamounts is considered unlikely. Population genetics studies indicate that armourhead consists of a single seamount-wide population. Armourhead may survive up to 4–5years at the seamounts, however, individuals gradually become emaciated; undergoing an irreversible decline in somatic weight and body depth with age. Annual increases in armourhead biomass at these seamounts is therefore solely dependent on recruitment.

3.3 Habitat/ecology

Commercially-important deepwater bottomfish inhabit the slopes of island coasts and banks at depths of 100 to 400 m. Deepwater snappers are typically distributed in a clumped pattern throughout their spatial and depth range and are often associated with underwater headlands and areas of high relief. Although deepwater snappers are generally thought of as top-level predators, several snapper species in the Pacific are known to incorporate significant amounts of zooplankton in their diets (Haight

Three species of seamount groundfish are included as BMUS in the FMP. These deepwater species primarily occur at depths of 270–500 m at Hancock Seamount, which is located 2800 km northwest of Honolulu. The seamount species generally occur at higher latitudes and below the depth range of the snapper-grouper bottomfish species complex. Armourhead and alfonsino spawn free-floating eggs, which are dispersed by the North-equatorial and Kuroshio currents. Juvenile fish remain in the pelagic environment for up to a year and then descend to seamount summits and begin a demersal existence. These species feed on species associated with the deep-scattering layer (euphausids, copepods, shrimps, myctophids, etc.) and make vertical migrations at night to follow their prey.

3.4 Fishery characteristics

3.4.1 Gear and methods

The basic design of the handline gear used in Hawaii’s bottomfish fisheries has remained essentially unchanged from gear used by early native Hawaiians (Haight et al. 1993). The gear consists of a main line constructed of dacron or monofilament with a 2–4 kg weight attached to the end (Figure 3). Several 40–60 cm sidelines with circle hooks are attached above the weight at 0.5–1 m intervals. A chum bag containing chopped fish or squid may be suspended above the highest of these hooks. The gear is retrieved using hydraulic or electric reels after several fish are hooked.

Bottomfish terminal rig


Circle hooks are generally used for their self setting ability and their curved design with long inward-facing hook points that make it difficult for the fish to escape once they are embedded. Circle hooks used in the bottomfish fishery are typically flat by design. “Kirbed”hooks (bent or offset to the side) are also available but are not generally used. Flat circle hooks work well for fish that engulf and move off with bait in their mouth. As a fish moves off with the baited hook, the line will trail out of the corner of the fish’s mouth. The hook is then drawn to the corner of the mouth where the motion of the fish in relation to the pull of the line will rotate the hook through the corner of the jaw. In addition, circle hooks are less prone to snag on rocky or hard substrate bottoms. This characteristic minimizes the loss of gear (Kawamoto, NMFS, Hawaii, pers. comm.).

All demersal fishermen in Hawaii target the same assemblage of bottomfish species. The ability to target particular species varies widely depending on the skill of each captain. Electronic navigation (GPS) and fish-finding equipment (sonar) greatly aid fishermen in returning to a particular fishing spot and catching desired species with little incidental catch (Haight et al. 1993).

3.4.2 Vessels

In contrast to the main Hawaiian island bottomfish fishery, fishing in the NWHI is conducted solely by part-time and full-time commercial fishermen. Vessels in the NWHI tend to be larger than those fishing around the MHI as the distance to fishing grounds is greater (Haight et al. 1993).

As the number of vessels participating in the NWHI fishery increased during the 1980s, the fleet characteristics of the fishery became more diverse. Pooley and Kawamoto (1990) divided the fleet into three groups based on size and mode of propulsion: motor sailors, medium-sized powered vessels and large-sized powered vessels. The motor sailors are 46 to 66 ft long and are more streamlined in hull design than the standard powered vessels. The sail can be used to save on fuel, but this limits the hold capacity compared with powered vessels of similar length. The powered vessels generally share one characteristic: a large working area on the aft deck. The medium-sized powered vessels are 42 to 49 ft long. Because their smaller size limits fishing range and hold capacity, they usually operate in the lower (southeastern) end of the NWHI or in the MHI. The larger powered vessels are 47to 64 ft long. With an average fuel capacity of 1500 gallons, the vessels have a maximum range (round-trip) of 1800 miles. The average maximum hold capacity is 15000 lb.

3.4.3 Fishing strategies

Many boats that fish in the Mau Zone participate in multiple fisheries. The majority of vessels fishing in the Mau Zone are generally active during a season, which extends from November to April.

A 1993 survey of participants in the NWHI fishery found that vessels fishing in the Mau Zone made on average 12.7 trips a year to the area to target bottomfish and 3.4trips to target pelagic fish or a mixture of pelagic species and bottomfish (Hamilton 1994). In addition, during that year an average of 5.6 trips were made by these vessels to bottomfish fishing grounds around the MHI. Although bottomfish fishing in the Mau Zone is not the only activity of these boats, it may be vital to the successful year-round operations of some fishermen.

Fishing strategies and catches of vessels fishing in the Hoomalu Zone tend to be fairly uniform (Pan 1994). A 1993 survey found that all boats fishing in the Hoomalu Zone were engaged exclusively in commercial bottomfish fishing (Hamilton 1994). They averaged nine trips a year to the zone and the average trip length was about three weeks.

Popular fishing grounds in the Mau Zone include the waters around Nihoa Island and Necker Island. Especially productive fishing areas in the Hoomalu Zone are Brooks Bank, Laysan Island and Gardner Pinnacles. During rough sea conditions bottomfish fishing vessels that take refuge in the relatively sheltered waters around French Frigate Shoals may fish on relatively shallow (10–50fm) banks (WPRFMC 2000a).

3.4.4 Landings

Virtually all of the bottomfish caught in the NWHI fishery are sold and therefore are required to be reported under State of Hawaii law (Table 2). NWHI bottomfish landings grew dramatically in the mid-1980s and then tailed off, stabilizing in the 1990s at a level slightly below the MHI bottomfish landings.

Beginning in the late 1960s, large catches of armourhead were made by foreign fishing vessels for about ten years until overfishing caused the fishery to collapse. There has never been a domestic seamount groundfish fishery in the US western Pacific region.

Table 2
Commercial bottomfish landings in NWHI, 1984–2001 (1000lbs = 453.59 kg)

1987NANANANA1 015460

3.4.5 Markets

A market for locally caught bottomfish was well-established in Hawaii by the late nineteenth century. Today, fresh bottomfish continue to be an important seafood for Hawaii residents and visitors. Nearly all bottomfish caught in the NWHI fishery are sold through the Honolulu fish auction. Prices received at the auction change daily and the value of a particular catch may even depend on the order in which it is placed on the floor for bidding (Hau1984). Bottomfish sales have also occurred through less formal market channels, e.g. local restaurants, hotels, grocery stores and individual consumers are important buyers for some fishermen. However, due to new US Food and Drug Administration rules regarding seafood safety and handling, most sales are now primarily channeled through wholesale-type dealers. In addition to being sold, bottomfish are eaten by fishermen and their families, given to friends and relatives as gifts, and bartered in exchange for various goods and services.

Historically, the demand for bottomfish in Hawaii has been largely limited to fresh fish. Seventy years ago Hamamoto (1928) remarked that fish dealers in Honolulu refused to buy fish that had been harvested in the NWHI and frozen on-board because the demand for this product was so low. In the last few years the price differential between frozen and fresh product has narrowed for some species of bottomfish, but it remains substantial for onaga and ehu, the two highest priced fish. Until the market for frozen bottomfish develops, participants in the NWHI fishery will be caught in the same on-going dilemma -they must stay out long enough to cover trip expenses, but keep the trips short enough to deliver a readily saleable, high-quality product (Pan 1994). In the past, bottomfish catches from the MHI have tended to command higher aggregate prices than those caught in the NWHI, reflecting a larger proportion of preferred species and greater freshness. Bottomfish caught around the MHI are iced for only one to two days before being landed, whereas NWHI fresh catches may be packed in ice for ten days or more. By the late 1990s, however, the prices appeared to converge, perhaps due to the softness of the upscale part of the Hawaii market as the State’s economic recession continued (WPRFMC 1999).

Catches of bottomfish around the MHI typically consist of plate-sized fish preferred by household consumers in Hawaii and by restaurants where fish are often served with the head on. Bottomfish caught around the NWHI tend to be the medium to large fish (> 5 lbs) preferred by the restaurant fillet market. Because the edible yield is high, handling costs per unit weight are lower and more uniform portions can be cut from the larger fish.

Pooley (1987) showed that Hawaii auction market prices increase when MHI landings drop. However, during the 1990s the relationship between price and volume faltered, perhaps due to an increase in imported fresh fish that competed in the market with locally-caught bottomfish (WPRFMC 1999). Since 1996, the average annual amount of fresh snapper imported into Honolulu has been 460343 lbs (20900 kg), with a free-alongside-ship value of $1238548 (NMFS Fisheries Statistics and Economics Division undated). Not only has the quantity of foreign-caught fresh fish increased during the last few years, but the number of countries exporting fresh fish to Hawaii has also increased. A decade ago, for example, fresh snapper was exported to Hawaii mainly from within the South Pacific region. In recent years, fresh snapper has also been received from nations as far away as Vietnam, China and Madagascar.

3.5 Historical participation

Bottomfish fishing was a part of the economy and culture of the indigenous people of Hawaii long before European explorers first visited the islands. Descriptions of traditional fishing practices indicate that native Hawaiians harvested the same deep-sea bottomfish species as the modern fishery and used some of the same specialized gear and techniques employed today (Iversen, Dye and Paul 1990). The poo lawaia (expert fishermen) within the community knew of dozens of specific koa (fishing areas) where bottomfish could be caught (Kahaulelio 1902). As Beckley (1883:10) noted, each koa could be precisely located:

“Every rocky protuberance from the bottom of the sea for miles out, in the waters surrounding the islands, was well known to the ancient fishermen, and so were the different kinds of rock fish likely to be met with on each separate rock….[They] took their bearing for the purpose of ascertaining the rock which was the habitat of the particular fish they were after, from the positions of the different mountain peaks.”

European colonization of the Hawaiian Islands during the early nineteenth century and the introduction of a cash economy led to the development of a local commercial fishery. As early as 1832, fish and other commodities were sold near the waterfront in Honolulu (Reynolds 1835). Other fish markets were established on the islands of Maui and Hawaii. John Cobb (1902), who investigated Hawaii’s commercial fisheries in 1900 for the US Fish Commission, reported that the bottomfish ulaula, uku and ulua were three of the five fish taken commercially on all the Hawaiian Islands.

Initially, the commercial fishing industry in Hawaii was monopolized by native Hawaiians who supplied the local market with fish using canoes, nets, traps, spears and other traditional fishing devices (Jordan and Evermann 1902, Cobb 1902). However, the role that native Hawaiians played in Hawaii’s fishing industry gradually diminished during the latter half of the nineteenth century as successive waves of immigrants arrived in Hawaii. Between 1872 and 1900, the non-indigenous population increased from 5366 to 114345 (OHA 1998). Kametaro Nishimura, credited by some to be the first Japanese immigrant to engage in commercial fishing in Hawaii, began his fishing career in the islands in 1885 harvesting bottomfish such as opakapaka, ulua and uku (Miyaski 1973). By the turn of the century, Japanese immigrants to Hawaii dominated the bottomfish fishery using wooden-hulled “sampans”propelled by sails or oars (Cobb 1902). The sampan was brought to Hawaii by Japanese immigrants during the late nineteenth century and over time Japanese boat-builders in Hawaii adapted the original design to specific fishing conditions found in Hawaii (Goto, Sinoto and Spehr 1983). The bottomfish fishing gear and techniques employed by the Japanese immigrants were imitations of those traditionally used by native Hawaiians with slight modifications (Konishi 1930).

During the early years of the commercial bottomfish fishery, vessels restricted their effort to areas around the MHI. Cobb (1902) records that some of the best fishing grounds were off the coasts of Molokai and notes that large sampans with crews of 4 to 6 men were employed in the fishery. Typically, the fleet would leave Honolulu for the fishing grounds on Monday and return on Friday or Saturday. The fishing range of the sampan fleet increased substantially after the introduction of motor powered vessels in 1905 (Carter 1962). Fishing activity was occurring around the NWHI at least as early as 1913, when one commentator recorded: “Fishing for ulua and kohala is most popular, using bonito for bait, fishermen seek this [sic] species in a 500 mile range toward Tori-Jima [NWHI]”(Japanese Consulate (1913), as cited in Yamamoto 1970:107). Within a few years more than a dozen sampans were fishing for bottomfish around the NWHI (Anon. 1924, Konishi 1930). Fishing trips to the NWHI typically lasted 15 days or more and the vessels carried seven to eight tons of ice to preserve their catch (Nakashima 1934). The number of sampans traveling to the more distant islands gradually declined due to the limited shelter the islands offered during rough weather and the difficulty of maintaining the quality of the catch during extended trips (Konishi 1930). However, during the 1930s at least five bottomfish fishing vessels ranging in size from 65 to 70 ft continued to operate in the waters around the NWHI (Hau 1984). In addition to catching bottomfish, the sampans harvested lobster, reef fish, turtles and other marine animals (Iversen et al. 1990).

During World War II the bottomfish fishery in Hawaii virtually ceased, but recommenced shortly after the war ended (Haight et al. 1993). The late 1940s saw as many as nine vessels fishing around the NWHI, but by the mid-1950s vessel losses and depressed fish prices resulting from large catches had reduced the number of fishery participants. During the 1960s, only one or two vessels operated around the NWHI.

There was renewed interest in harvesting the bottomfish resources of the NWHI in the late-1970s following a collaborative study of the marine resources of the region by state and federal agencies (Haight et al. 1993). The entry of several modern boats into the NWHI fishery and the resultant expanding supply of high-valued bottomfish such as opakapaka and onaga made possible the expansion of the tourism-linked restaurant market by providing a regular and consistent supply of relatively fresh fish (Pooley 1993a). Markets for Hawaii bottomfish further expanded after wholesale seafood dealers began sending fish to the US mainland. By 1987, 28 vessels were active in the NWHI bottomfish fishery, although only 12 fished for bottomfish full time (Table 4). Some of the part-time vessels also engaged in the pelagic or lobster fisheries (Iversen et al. 1990). In 1989, the Council developed regulations that divided the fishing grounds of the NWHI bottomfish fishery into the Hoomalu Zone and Mau Zone. Limited access programmes were established for the Hoomalu Zone and Mau Zone in 1988 and 1999, respectively, to avoid economic overfishing (Pooley 1993b, WPRFMC 1998).

Table 4
Number of vessels in the NWHI bottomfish fleet, Mau and Hoomalu zones


1 Based on a combination NMFS and HDAR data set.
2 Total may not match sum of areas due to vessel participation in multiple areas.
3 Based on HDAR data.

Since the NWHI bottomfish fishing grounds were divided into the Mau Zone and Hoomalu Zone in 1988, the Mau Zone has generally seen a greater share of the fishing effort as access to the Hoomalu Zone was restricted under a limited access programme (WPRFMC 1999). Since 1989, 17 permits to fish in the Hoomalu Zone have been issued, of which 15 have been used. In comparison to the Mau Zone, the Hoomalu Zone exhibits more continuity in participation, but the turnover has still been fairly high. Only about half of the active vessels fished in the Hoomalu Zone for more than two years.

Only five vessels harvested bottomfish in the Mau Zone in 1989, but during the 1990s an average of ten vessels fished in the area. The amount of effort (fishing days) expended in the Mau Zone has fluctuated along with the number of active vessels. Mau Zone activity levels peaked in 1994 with a total of 594 fishing days as a result of a combination of a relatively large fleet size and intensive activity by each vessel.

Eighty-one permits to fish in the Mau Zone have been issued since 1989, but only 37 of the permits were used. The turn-over rate has been high, with only 38percent of the 37 active vessels fishing in the Mau Zone for more than two years. A limited access programme was established for the Mau Zone in 1999 and currently ten vessels are allowed to fish in the area. Permits to fish in the Mau Zone are non-transferable and are subject to a’use-it-or-lose-it’requirement. At present, there is no procedure for issuance of new Mau Zone limited access permits. However, the Council approved a procedure based on historical participation in the MHI and NWHI fisheries and is preparing the final transmittal document for Secretarial review and approval.


4.1 NWHI reserve and sanctuary designation

An area of controversy involves the relationship between fisheries in the Northwestern Hawaiian Islands managed under the Bottomfish FMP and restrictions on fishing imposed by the Presidential Executive Orders creating the Northwestern Hawaiian Islands Coral Reef Ecosystem Reserve. In May 2000, President William Clinton issued a Memorandum stating that it is time to implement the Coral Reef Task Force’s recommendations to ensure the comprehensive protection of the coral reef ecosystem of the Northwestern Hawaiian Islands (NWHI)1. The Reserve was established by E.O. 13178 of 7 December 2000 and included certain conservation measures and Reserve Preservation Areas that are either completely closed to fishing or within areas where fishing is curtailed. Bottomfish conservation measures included grandfathering of existing permits holders as of December 2000, individual harvest limits and closed areas. The EO was revised and finalized by EO 13196, issued 18 January 2001. Further, the Secretary of Commerce was directed by the National Marine Sanctuaries Act Amendments of 2000 to initiate the process to designate the Reserve as a National Maine Sanctuary and, as required, has initiated this process. The National Marine Sanctuaries Office is in the process of developing management alternatives, including that for bottomfish, to be considered in the environmental impact statement for the designation of a NWHI Coral Reef Sanctuary.

1 The President’s directive coincided with Executive Order 13158, which requires federal agencies to establish a comprehensive national network of marine protected areas (MPAs) throughout US marine waters. The executive order calls for expansion of the nation’s MPA system to include examples of all types of US marine ecosystems. According to the executive order, a MPA means any area of the marine environment that has been reserved by federal, state, territorial, tribal or local laws or has regulations to provide lasting protection for part or all of the natural and cultural resources therein.

4.2 Overfishing Control Rule

The final rule implementing new biomass-based Overfishing/Control rules for bottomfish resources under the Council’s FMP was published in the Federal Register in August 2003. The Bottomfish Plan Team projected, based on existing estimates of catch per unit effort and maximum sustainable yield, that the “overfishing”threshold (effort component of the control rule) for the archipelagic bottomfish stocks may be exceeded. The Council is now working with the State of Hawaii and NMFS to validate current MSYestimates and refine and standardize catch per unit effort to reflect changes in fleet characteristics over time. In addition, the effects of recently established marine protected areas on how the status of stocks are evaluated must be assessed.

The Council will also be working with the Hawaii Institute of Marine Biology to conduct genetic studies on onaga and ehu to determine stock structure throughout the archipelago. A similar study was recently completed on hapuupuu, which suggested that genetic differences may exist along the Hawaiian archipelago. The Council is seeking funding to support the laboratory analysis component of the project and partners from agencies and industry to obtain fin clip samples from locations throughout the archipelago and other parts of the Pacific.

The Council, NMFS and State of Hawaii will host a stock assessment workshop on 13–16 January 2004 at the Council office to determine the status of Hawaii bottomfish stocks. The objective of the workshop is to develop a plan to improve data collection and assessment methodology to a point where reliable resource assessments can be obtained. Accordingly, the workshop will (a) evaluate existing biological, oceanographic and fisheries data as well as stock assessment systems relating to bottomfish resources in Hawaii and the other US island areas, (b) identify weaknesses and inadequacies in current assessment methods and supporting data, (c) review alternative approaches to modeling and stock assessments and (d), propose a course of action to improve stock assessment methods and associated data

4.3 Ecosystem-based management

4.3.1 Policy Directions

Integrating ecosystem principles into fishery management plans and developing ecosystem-based management regimes is identified as one of the highest priorities for the National Oceanographic and Atmospheric Administration (NOAA 2003). The Council has led the way in this effort by implementing the first ecosystem-based plan -the Coral Reef Ecosystem FMP. Efforts will now focus on integrating ecosystem principles into existing plans, such as the Bottomfish FMP. Efforts will focus on trophic level interactions, mitigating bycatch, reducing impacts to habitat and, in particular, avoiding protected species interactions.

4.3.2 Bycatch

The Magnuson-Stevens Act direct Councils, “to the extent practicable, (A) minimize bycatch and (B) to the extent bycatch cannot be avoided, minimize the mortality of such bycatch”. Bycatch is defined as any fish that is returned to the sea -no matter if it is dead, alive or damaged. Given this definition, fishermen in the Pacific Ocean who return live fish or participate in conservation efforts, such as tag and release programmes, compromise National Standard 9, which is intended to reduce bycatch. This is not true for Atlantic Ocean fisheries, which are exempt from this standard. The Council is working with NMFS and Congress to correct this problem.

Being a hook and line rig, the gear used is relatively selective, with the ability to successfully target particular species groups dependant upon the skill of the fisher. Experienced vessel crews are able to catch the desired species with little bycatch, however, it is impossible to completely avoid non-target species.

Logbook data and research programmes conducted by the State of Hawaii and the NMFS indicate that bycatch accounts for approximately 8–19percent of the total catch in bottomfish fisheries in the Hawaiian archipelago. Sharks, oilfish, snake mackerel, pufferfish and moray eels are the most numerous discard species and not kept by vessels because ther are unpalatable. Other reasons for discards include concerns for ciguatoxic poisoning, economic factors, product shelf-life and fish damage. The major discard species in the NWHI bottomfish fishery are given in Table 5.

Table 5
NMFS logbook estimates of discards in the NWHI deepwater bottomfish fishery, 1997

Scientific nameCommon nameNumber discarded
Seriola dumerilliamberjack2 120
Caranx ignobilisblack trevally1 298
P. filamentosuspink snapper215
Charcarhinidaemisc. sharks166
Epinephelus quernusseabass114
Etelis carbunculusred snapper98
P. zonatusyellowband snapper98
Aprion virescensjobfish87
Pristipomoides auricillayellowtail snapper19
Carangidaemisc. jacks7
Galeocerdo cuvierTiger shark5
Aphareus rutilansred snapper2

The largest component of the releases is that of kahala (Seriola spp.). Kahala was once an important commercial species, but due to the presence of ciguatoxin in some fish it has not been sold for many years due to liability concerns. It is thought that since kahala are caught in such large numbers while fishing for the targeted species their population represent competition for food and habitat resources. Large kahala are also known to feed on the valuable bottomfish species, often stealing them off the hooks and thus contributing to the inefficiencies of the fishing operations. The fishermen release the majority of kahala they catch although they may from time to time use them as bait or chum. Releases can be either live or dead depending on the preference of the captain. The percentage of live releases to dead releases is unknown. Many of the NWHI captains voluntarily participate in the State of Hawaii’s ulua tagging study and routinely tag many kahala and other jacks.

Conservation, or stock related releases, are another component of the release strategy employed by the fishermen. The NWHI fishermen have been releasing a low number of small-sized high-value BMUS species live such as onaga, opakapaka, ehu and uku. Large numbers of various commercially low-valued species (ie., butaguchi, kalekale and white ulua) are also released live to reduce and minimize waste of fishery resources.

4.3.3 Impacts of habitat

Bottomfish gear has limited impacts on fish habitat. Habitat damage may occur from deployment of anchors during deepwater fishing activities. However, impacts are highly localized as the targeted fishing habitat is focused primarily on the 200 m contour areas with high relief. Anchoring positions during such fishing operations would generally be at depths from 60–350 m (30 to 175 fm). Reef building corals are generally not found below 100m, the lower extent of light attenuation. It is estimated that suitable bottomfish habitat where vessels might anchor represents approximately one percent of the total bank habitat. Shallow water bottomfish activities are conducted while drifting, therefore minimizing the potential for anchor damage.

The National Marine Fisheries Service, State of Hawaii Division of Aquatic Resources and Hawaii Undersea Research Laboratory have conducted a series of submersible dives on bottomfish habitat in the main and northwestern Hawaiian islands. Evidence of fishing related impacts on habitat in the NWHI has not been observed to any significant extent.

4.3.3 Protected species considerations

Concerns have been raised about the possible effect of the Northwestern Hawaiian Islands bottomfish fishery on populations of the Hawaiian monk seal through competition for bottomfish resources. Monk seals, which are listed as endangered under the US Endangered Species Act, are opportunistic feeders, consuming a wide variety of prey items. There does not appear to be any geographic correlation between areas heavily fished for bottomfish and declining monk seal populations. On the other hand, the relative importance of bottomfish in the monk seal diet is poorly understood. The NMFS is conducting research using fatty acid analysis to determine if, and to what extent, bottomfish is an important component in monk seals’diet.


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