Stock Assessment Confirms Overfishing of Parrotfish in the Main Hawaiian Islands

posted in: April 2015, Fisheries | 0

IMG025There’s an 89 percent chance that commercial fishermen in the Main Hawaiian Islands are catching uhu, commonly known as parrotfish, at an unsustainable rate. That’s according to Cassandra Pardee, a Hawai`i Pacific University graduate student who has recently completed a stock assessment of the fish.

Her work, funded in part by the Western Pacific Fishery Management Council (Wespac), is aimed at helping the National Marine Fisheries Service produce a more accurate annual catch limit (ACL), which the agency requires for all managed fisheries.

Last year, when setting the ACLs for the coming year, Wespac was presented with information that commercial catches in 2012 and 2013 vastly exceeded the Hawaii parrotfish ACL of 33,326 pounds. In 2012, the catch was 77,678 pounds and grew to 84,813pounds the following year.

The council’s staff and its Scientific and Statistical Committee (SSC) last June stated that the ACL exceedance was not a sign of overfishing, but was probably just the result of improved reporting following the state’s implementation of a violation system that penalizes licensed commercial fishermen who fail to file catch reports.

“I guess we’re victims of our own good advances in catch reporting in a more real-time basis,”SSC chair Charles Daxboeck said at the time.

Council staff also pointed out that the ACL was a first crack at setting an appropriate fishing limit and was set before the state had improved its reporting system.

Pardee’s assessment suggests that the ACL is, indeed, a little low. Using a model that included the catch records of just commercial spearfishers, she determined the maximum sustainable yield (MSY) for parrotfish to be about 41,324 pounds, which is about 10,000 pounds more than the 2012 ACL. Usually, ACLs are set slightly lower than MSY, so the current ACL is off, but perhaps not by much.

In any case, Pardee told the SSC last month, the overall population has decreased, but there is a 76 percent chance that parrotfish are not in an overfished state. However, between 2010 and 2012, there was a high probability that overfishing was occurring, she said. Overfishing happens when the catch rate exceeds the rate that produces MSY. The fact that catches have continued to increase suggests that overfishing continues.

Pardee pointed out that her MSY calculation reflects only the exploitable biomass available to commercial fishers and does not reflect the entire population of parrotfish in the Hawaiian islands. Her model did not include recreational catch even though it likely exceeds commercial catch, she said.

SSC member John Sibert, a fisheries scientist, said he’s often wondered what would happen to stock assessments if modelers just doubled the catch to capture what the recreational fishermen might be doing.

Pardee said that would raise the total biomass, but the population trend curve would still be about the same. Maximum sustainable yield would also increase, but since government agencies are only managing the commercial catch, the MSY would be so high it would seem unachievable, she said.

“So are we better off not knowing [the recreational catch]? I’m serious,”Sibert said.

Pardee replied that it would be beneficial to know what is happening in total if agencies are going to manage both commercial and recreational catch. The state, for example, has already adopted regulations over the past couple of years attempting to manage parrotfish catches —both commercial and non-commercial —in West Hawai`i, Maui, and Lana`i.

Pardee noted that a spike in commercial parrotfish catches in recent years can be attributed to three spear-fishermen who, according to interviews, are night-fishing with SCUBA. SSC member Craig Severance added that there have been complaints in the Kona community that these top fishermen have been shipping out coolers of parrotfish.

In response, the state Department of Land and Natural Resources’Division of Aquatic Resources proposed a ban on spearfishing with SCUBA in waters off West Hawai`i. Over the objections of a number of commercial fishermen, the Board of Land and Natural Resources approved the ban in 2013.

Last year, after years of failed attempts by state legislators to pass bills severely restricting or banning outright fishing for parrotfish around Maui, the Land Board narrowly adopted regulations  banning the take of certain species/sizes of parrotfish, limiting the number of parrotfish that can be taken around Maui or Lana`i per day, and increasing the minimum size limit of those species that can be taken from 12 inches to 14 inches.

Commercial fishermen opposed those regulations as well, and suggested instead a ban on night fishing.

At the SSC meeting last month, chair Daxboeck noted that nighttime spear-fishing is restricted in French Polynesia, where he lives.

“You can pull out the parrotfish, check the size and put it on your spear [at night], where in the day, you may have to chase it down,”he said.

He asked DAR’s Alton Miyasaka, who often represents the state of Hawai`i on the council, whether the DLNR considered adopting a night-fishing ban.

Miyasaka noted that the department had considered it. It had not, however, proposed such a ban to the Land Board.

“My recollection was that the fishermen generally supported a night-spearing ban on uhu, but they felt it would shift the effort to the day fishery. Their argument is that you wouldn’t see a decline in total catch. …I disagree,”Miyasaka said. “You would probably have a big change.”

“We should probably have more discussion,”he said.

Pardee did not have a chance to present her findings to the full council last month, but she was one of the speakers during the council’s Fishers’ Forum —held outside of the meeting —on stock assessments. How her work will inform a new ACL for parrotfish remains to be seen.

For Further Reading

Past articles in Environment Hawai`i have discussed parrotfish catches. They include:

  • “DLNR Proposes Strict Size, Bag Limits On Fish Catches Around Maui, Lana`i,” and “Land Board Approves West Hawai`i Fishing Rules,” Board Talk, August 2013;
  • “Rules to Protect Maui Parrotfish, Goatfish Win Land Board Approval by One Vote,” Board Talk, November 2014.


Panel Finds Bottomfish Assessment Is Not the Best Available Science

It appears the Western Pacific Fishery Management Council wasn’t entirely off base last year when it defied the National Marine Fisheries Service and the Pacific Island Fisheries Science Center and took the position that the center’s new Main Hawaiian Island bottomfish stock assessment was not the best available science.

The council voted last October to keep the annual catch limit (ACL) for MHI bottomfish at 346,000 pounds, a level that was based on NMFS’s 2011 stock assessment. NMFS and the science center had by then come out with a new stock assessment that suggested the ACL was about 80,000 pounds too high. Local commercial bottomfishermen lobbied hard to keep Wespac from concurring, arguing that the stock is actually doing just fine. Members of the council’s SSC also found fault with the science center’s change in the way it approached the stock assessment – specifically, the center’s method for standardizing data on fishing effort. As a result of the council’s action, the 2014-2015 bottomfishing year began in September without an ACL.

In December, the stock assessment underwent review by the Center for Independent Experts (CIE). In short, the CIE panel of four fisheries experts found that the assessment was not the best available science.

“To coin a phrase from a perfect movie, there’s some good, some bad, and some ugly,”said Gerard DiNardo at the SSC’s meeting last month where he reported on the CIE panel’s findings. DiNardo was, until recently, the PIFSC’s lead stock assessment scientist.

The good: Contrary to the SSC’s initial criticisms, the CIE panel thought the science center’s standardization of the catch-per-unit-effort (CPUE) data was an improvement over the 2011 stock assessment. The panel also said the assessment modeled its results correctly.

Other than that, the panel found that the quality of catch-and-effort data from the Division of Aquatic Resources was suspect. Because that information was used to derive CPUE, any conclusions made from it is also suspect, PIFSC scientist Annie Yau told the council at its full meeting. (Yau is the main author of the 2014 assessment.)

What concerned the CIE panel most was that the science center had not used all available data. DiNardo said three days before the CIE review, it was brought to his attention that data that could have further improved the CPUE standardization were not included in the assessment.

“That data was provided to us about 10 years ago,”he told the SSC. “I was not aware of it nor was any stock assessment scientist. …I can’t say it would have helped the assessment, but it was there. That was a major concern by the CIE review, that there was data not brought into the assessment.”

During the council meeting, Yau suggested that the CIE’s interpretation of “best available science”was different from the way Wespac and the National Oceanic and Atmospheric Administration (parent agency to NMFS) use the term. Even so, DiNardo told the SSC, his agency had to concur with the CIE’s conclusion that the assessment was not the best available science. “We use the CIE as the gold standard,”he said.

DiNardo said the PIFSC plans to explore the CIE’s recommendations, as well as alternative models to fully utilize the available data, and that a complete benchmark MHI bottomfish stock assessment will be completed in 2017.

In the meantime, NMFS will be taking steps to adopt the council’s October recommendation and set the ACL for the rest of this fishing year at 346,000 pounds, according to Jarad Makaiau of NMFS’s sustainable fisheries division.

After that, the PIFSC will simply update the 2011 stock assessment until a new, full stock assessment is produced, he said.

A proposed rule for the current ACL is expected to be published early this month and, after public comments, adopted in early May.

“We don’t expect the ACL to be reached in this fishing year,”he said. As of press time, the fishery had caught about 243,000 pounds.

NMFS Nixes Proposal to Delist Green Turtles

Citing the threats posed by climate change and sea level rise, the National Marine Fisheries Service and the U.S. Fish and Wildlife Service have denied the Association of Hawaiian Civic Clubs’ 2012 petition to delist the Hawaiian population of green sea turtles, the vast majority of which nest on the low-lying islets of French Frigate Shoals in the Northwestern Hawaiian Islands.

Last month, the agencies published a 12-month finding and a proposed rule in the Federal Register responding to the petition and detailing their reasons for breaking the green sea turtle population up into about a dozen distinct population segments (DPS).

As requested in the AOHCC petition, the agencies determined that the Hawai`i population is, indeed, a DPS. They also determined the population around American Samoa to be distinct, as well as the population residing around Guam and the Commonwealth of the Northern Mariana Islands. Both populations are proposed to be up-listed from threatened to endangered.

In all, the agencies are proposing a total of 11 green turtle DPS.

With regard to the Hawai`i population, identified as the Central North Pacific DPS, the agencies acknowledge that it has grown over the years. In fact, it was that growth that prompted the AOHCC to ask for delisting.

However, they state, “in spite of the positive [population] trends in the last few decades, the unprecedented concentration of nesting at one site and moderately lower population size raise serious concerns about the resilience of this DPS, particularly its ability to adapt to future climate scenarios. Ninety-eight percent of the population nests are low lying atolls (96 percent nesting in a single low-lying atoll), making them extremely vulnerable to sea level rise —some effects of which have already been witnessed.”

Other effects of climate change include increasing temperatures at nesting beaches that may affect hatchling sex ratios and embryonic development,they state.

A public hearing on the proposed rule will be held on April 8, from 6 to 8 p.m. at the Japanese Cultural Center in Honolulu, and public comments will be accepted until June 22.

The proposed rule is a blow to the Western Pacific Fishery Management Council, which for years has sought ways to provide for the harvesting of green sea turtles. Some council staff, in fact, had a hand in preparing the AOHCC petition.

At its meeting last month, council staffer Asuka Ishizaki hesitated to delve into her efforts to meet the council’s June 2014 directive to start looking at ways to include green sea turtles as a management species under the council’s fishery ecosystem plans (FEP). At the time, the NMFS had not yet issued its 12-month finding and proposed rule, but was expected to announce it soon.

Ishisaki said it would be best to “wait until the delisting or petition response is out. We’re not ready to discuss the details with you.”

NMFS and FWS announced their proposed rule two days later.

— Teresa Dawson

Leave a Reply