In an effort to address the problem of severe overfishing of two species of prized bottomfish — `ehu and onaga — the state Board of Land and Natural Resources has adopted rules setting aside approximately 20 percent of the bottomfish grounds around the Main Hawaiian Islands.
The provision requiring area closure of 19 separate areas is one of five control measures intended to improve chances of the stocks recovering. The other measures are:
Gear restrictions: Catching bottomfish with any trawl, trap, bottomfish longline or net is prohibited.
Recreational bag limits: Recreational fishermen may not take or possess more than five onaga or `ehu, or a combined total of five of both.
Vessel identification numbers: This provision makes it unlawful for people to catch bottomfish on a vessel that does not have an approved vessel identification number.
Control date: Persons who fish in the bottomfish fishery on or after the control date will not be assured continues participation if the Department of Land and Natural Resources at some later date decides to limit the number of boats allowed in the fishery.
Not everyone agrees on a best way to manage the fishery, says Walter Ikehara of the DLNR’s Division of Aquatic Resources. Ikehara should know: as the point person for the DLNR at meetings with fishermen and fisherwomen over the last three years, Ikehara has the battle scars to prove it.
However, Ikehara adds, the rules are the best the state has come up with in the three years DLNR chairman Mike Wilson instructed the DAR to develop a bottomfish management plan. Whether the rules will be sufficient won’t be known for years.
Enforcement Questions
Enforcement is a key to the effectiveness of closed areas. Gary Moniz, acting administrator of the DLNR’s Division of Conservation and Resource Enforcement, testified at the Land Board’s March 13 meeting that routine patrols with the U.S. Coast Guard and a database dedicated to complaints will help enforce the area closures.
Commander Jack Rutz, the Coast Guard’s chief enforcement officer in the 14th District (which includes Honolulu), is less optimistic. Rutz says his agency will cooperate with the state by allowing one state enforcement officer ride on its boats or helicopters when they are patrolling in closed areas. And, he adds, “on our own, if we’re patrolling in a closed area and see a [violator], we’ll gather information and hand it over to the state.”
But, at an April meeting of the Western Pacific Fishery Management Council, Rutz spoke in opposition to the state plan. “The enforcement of 20 irregular, small areas is impossible,” he said, adding that, in his view, the plan was altogether unenforceable.
Will It Be Enough?
Giving urgency to management measures are changes in federal law. When Congress passed the Sustainable Fisheries Act of 1996, which amends the Magnuson-Stevens Fishery Conservation and Management Act, it required the secretary of Commerce to give Congress an annual report of overfished stocks. The first list, published in September 1997, included the Main Hawaiian Islands stocks of onaga and `ehu.
Under the SFA, the councils must develop management plans that allow overfished stocks to be restored in 10 years. The definition of what constitutes restoration is stricter under the SFA than it had been. Previously, bottomfish were defined as overfished when their spawning potential ratio (a rough measure of a stock’s ability to reproduce) fell below 20 percent of estimates of pre-fishing SPR. Now, any fishery where the stocks fall below “maximum sustainable yield” is to be defined as overfished.
This means two things for the Main Hawaiian Islands bottomfish fisheries. First, onaga and `ehu will probably be joined by hapu`upu`u (grouper, or sea bass) and opakapaka. Under the new SFA definition, they, too, probably will be categorized as overfished. National Marine Fisheries Service scientists estimate that the “maximum sustainable yield” for most bottomfish equals an SPR of 30 to 40 percent. Thus, no longer is recovery to be defined by 20 percent SPR, but will be roughly double that.
Second, the SFA may mean that the recovery anticipated under the state’s bottomfish management plan may be too little to meet federal requirements. Don Kobayashi, a NMFS scientist, has estimated that for onaga, maximum sustainable yield is equivalent to an SPR of 32 percent. To rebuild onaga in the main Hawaiian Islands to this level in 10 years, Kobayashi says, would require a 57 percent reduction in fishing effort, over and above the 20 percent area closure.
In other words, if the state closure remains as proposed, more than half the boats now fishing would have to be removed from the bottomfish fleet in the Main Hawaiian Islands. Alternately, Kobayashi says recovery of onaga could be achieved in the 10-year time frame without any reduction in fishing effort, but that would require nearly doubling the closed areas, to 35 percent of the bottomfish grounds.
A Way Out?
Populations of bottomfish in the Northwestern Hawaiian Islands, where fishing effort is much more limited, are in robust good health — so healthy, in fact, that if fishery managers average the spawning potential ratios of bottomfish stocks in the Northwestern islands with those in the Main Hawaiian Islands, the resulting SPRs are high enough to remove the stocks from the overfished list.
Such averaging is justifiable if the overfished stocks in the Main Hawaiian Island are part of what fishery managers call an archipelagic-wide stock. NMFS scientists in Honolulu say that preliminary genetic work supports this idea.
As explained by NMFS scientist Bob Moffitt, the scientists think that the larvae from bottomfish populations in the Northwestern Islands are carried by ocean currents in a southeasterly direction. Under this scenario, most of the adult fish in waters off the Main Hawaiian Islands were spawned in the Northwestern Islands.
What happens to larvae spawned in the Main Hawaiian Islands? According to this theory, if they drift southeasterly far enough, they end up as fish food, since suitable habitat for these species to develop does not exist much beyond the island of Hawai`i at the southern end of the chain.
At the April meeting of the Western Pacific Fishery Management Council, council members voted to accept the recommendation of its bottomfish plan team and its scientific and statistical committee to calculate the health of bottomfish stocks on an archipelagic-wide basis.
Could this let Hawai`i off the hook, so far as managing bottomfish in the Main Hawaiian Islands is concerned?
Not likely, say those familiar with the issue. The MHI bottomfish stocks and those in the Northwestern islands are, economically, two different fisheries. Even though the two groups may be genetically linked, there is still a need to manage them separately if maximum sustainable yield is to be attained, says Moffitt.
Unreliable Reports
Adding to the inherent difficulty of managing species that are, in the main, poorly understood and little researched is the lack of reliable data submitted by fishers themselves.
What little is known is based largely on catch reports from commercial fishers, which are hardly known for their reliability, says Bill Devick, acting administrator of the Division of Aquatic Resources.
“We really don’t know very much at the present about the bottomfish,” says Devick. Despite this, Devick maintains that area closures are the way to go to bring the numbers of onaga and `ehu back up. “Other things that we use — bag limits, size limits, seasons, etc. — are good tools under limited circumstances of very good enforcement.” But, he adds, the tool of closing off areas is the “one thing that seems to be working elsewhere in both the Pacific and the Atlantic.”
Another problem in managing bottomfish, in particular, is the lack of data on the take of bottomfish by recreational fishers. For years, the state has extrapolated the recreational take by relying on estimates made in a study conducted more than 10 years ago. NMFS has criticized state reports of recreational catch derived in this manner. At the April meeting, the Fishery Management Council agreed with the advice of its scientific and statistical committee and bottomfish plan team to cease the practice of estimating total recreational catch in Hawai`i in this fashion.
Stock Enhancement
If the stocks cannot be brought back through management measures alone, the state is considering using artificial stock enhancement. Toward this end, the state is spending $425,000 ($187,500 of which is from the federal government) to pay researchers at the University of Hawai`i to explore ways of raising bottomfish in captivity. The program, undertaken by the UH Hawai`i Institute of Marine Biology, is now in its second year.
Whether stock enhancement will work is hard to say. The researchers have managed to keep an `ehu alive for three and a half weeks; two onaga have survived for a week and a half. The fish, which normally live at great ocean depths, have experienced such problems as their eyes popping out and parasites on their gills and fins.
While the program may increase fishery managers understanding of such species, “stock enhancement is not the means by which the bottomfish fishery is going to be restored,” Devick says. Still, “once we get a handle on how to manage the fishery, then it [stock enhancement] could be one of the tools.”
State Conducts Ta`ape Study
Also approved at the April Land Board meeting was the continuation of a study on an introduced fish, the ta`ape, which many fishers believe is responsible for the decline of more delectable species.
When completed, the study could alter the state’s approach to bottomfish management. “Whatever the results are, if [ta`ape] are in fact responsible for the decline of any fishery, we still have to respond,” says DAR head Bill Devick. Should the ta`ape turn out to be a problem, he adds, “the measures that are being taken to replenish the onaga and `ehu fishery may not be adequate.”
Decades ago, many scientists believed that Hawai`i’s ecosystem had room for and was in need of additional aquatic fauna. So, following recommendations from leading fisheries experts of the time, the state brought in all kinds of fish –including the ta`ape — to fill niches that those experts said needed occupants.
Ta`ape not only filled its niche, it “went gangbusters,” according to Devick.
Today, the abundant ta`ape is the fishers’ scapegoat for the decline of bottomfish.
On April 24, the Land Board approved the extension of five research agreements with the University of Hawai’i. One of them was a two-year study of interactions of the ta`ape (or blueline snapper) with onaga, `ehu and opakapaka. The study focuses on the possible predation and competition for food and habitat by the ta`ape.
The results of this research so far (which is being carried out by the University of Hawai`i’s Cooperative Fishery Research Unit) suggest that the ta`ape may be getting a bum rap from fishers. According to researcher Chris Kelly, not a single ta`ape has been caught after at least a hundred forays into bottomfish territory. This has led to speculation that ta`ape inhabit shallower waters and may not directly interact with the deepwater bottomfish.
“If that is the case,” Devick says, “it doesn’t diminish the significance of this species because it is far more abundant at depths shallower than the onaga and `ehu are found. So, there is a strong possibility that they are competing with other bottomfish species or, more importantly, with reef fish.”
— Teresa Dawson
Volume 8, Number 12 June 1998
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