In late November, the Hawai‘i deep-set longline fleet, which targets bigeye tuna, caught three false killer whales in federal waters off the Big Island. All of them were release alive, but had been hooked in the mouth area and freed with hooks, wire leaders, weights, and branch lines attached.
The National Marine Fisheries Service (NMFS) had not yet announced by press time whether the whales’ injuries were serious enough to likely end in their deaths, which could influence whether longliners will be allowed to resume fishing this year in the swath of waters south of the Hawaiian islands known as the Southern Exclusion Zone (SEZ).
In accordance with its false killer whale take reduction plan, NMFS closed the zone last February after the fleet killed one false killer whale and seriously injured another within the 200-mile exclusive economic zone (EEZ) around the islands a month earlier. It was the second time NMFS closed the SEZ in two years.
Under the criteria set forth in the take reduction plan, the zone can only be reopened now if 1) after receiving the federal take reduction team’s recommendations, the agency determines that reopening is warranted; 2) in the two years following the closure, the fishery has no observed false killer whale mortalities or serious injuries (M&SI) in the federal waters that are still open; 3) the fishery reduces its total M&SI rate by an amount equal to or greater than the rate necessary to reduce M&SI to below the pelagic stock’s potential biological removal (PBR) level; or 4) the recent average M&SI level in the fishery within the open federal waters is below the PBR level for the pelagic stock at that time.
The agency’s past practice has been to consider mouth hookings of false killer whales serious injuries. However, NMFS officials said last year that the agency was reviewing how it makes its serious injury determinations. Longer trailing gear would increase the potential to constrict the animal or impede breathing or feeding, Kevin Brindock of NMFS’s Protected Resources Division told the Western Pacific Fishery Management Council in June.
The animals caught in November were released with branch lines of 0.4, 0.9 and 10 meters in length.
Should NMFS determine the injuries to all three of these animals were serious, it’s unclear whether that alone would keep the SEZ closed.
Last March, fishery council staff suggested that the SEZ could reopen this year if the fleet limited its M&SI so that the most recent five-year average within the EEZ remained below the current PBR level of 9.3. The 2014-2018 average was 6.49.
According to Hawaiian false killer whale expert Robin Baird, who also sits on the animals’ take reduction team, “When 2019 is included, the high rate [of M&SI] from 2014 will drop out, so how much the average over the five years from 2015-2019 goes will depend on how many of the three remaining 2019 cases end up being serious injuries. If only two of them are, the five-year average will increase to approximately 7.17 (assuming the percent [of observer] coverage inside the EEZ is the same as it was in 2018). If all three of them are serious injuries then it will go up to about 8.37. If PBR remains at 9.3 (what it was in the last [stock assessment report]) then it’ll still be below PBR in either scenario.”
Baird’s hypothetical M&SI numbers for 2015-2019 assume that the fleet didn’t kill or seriously injure any false killer whales within the EEZ after November 25. It also assumes that there is no “observer effect,” where crews behave differently when federal observers are aboard.
The Hawai‘i deep-set longline fleet currently maintains observers on about 20 percent of its vessels. (Vessels where no observers are on board hardly ever report hookings of protected species, thereby making the percentage of observer coverage for the entire fleet an important factor in extrapolating the probable total number of incidents.) Baird noted that a false killer whale hooking in May was a case where the crew worked to help the animal free itself, which is what it is supposed to do. The fact that the injury to the animal in that case was not considered serious “plays a role in how the [serious injuries] are extrapolated to the unobserved takes,” he said.
In any case, NMFS Pacific Islands Regional Office administrator Mike Tosatto told the council last June that there was zero potential of reopening the SEZ by January 1, because data from all of 2019 had to be analyzed first to determine if the conditions for reopening the zone have been met.
Whether that occurs before NMFS sets a new PBR level remains to be seen. Amanda Bradford of the Pacific Islands Fishery Science Center’s Protected Species Division reported last October to the council’s Scientific and Statistical Committee that the agency was preparing a new false killer whale abundance estimate that will include data collected during a 2017 cetacean survey around the Hawaiian islands. The results of that work are expected to undergo external scientific review in March and a new PBR level will be set based on the new abundance estimate.
While the Hawai‘i Longline Association has complained that the closure of the SEZ leaves open only 17 percent of federal waters around Hawai‘i to fishing, the closure did not deter the fleet from burning though its annual bigeye quota of 3,554 metric tons set by the international Western and Central Pacific Fisheries Commission, as well as quota obtained through sharing agreements with American Samoa and the Commonwealth of the Northern Mariana Islands last year. Together those agreements allowed the fleet to catch an additional 2,000 metric tons.
Plan Amendments
It’s been more than six years since NMFS adopted the current false killer whale take reduction plan, and last year the agency made it clear that the plan was not working. Despite requiring vessels to employ stronger branch lines and weaker hooks to better allow hooked whales to work themselves free if the vessels maintain proper line tension, deaths and serious injuries have only increased.
A NMFS review of hookings both inside and outside the EEZ reveal that crews are often cutting branch lines. Sometimes the lines break.
To prevent the latter from happening, NMFS will initiate a study early this year that compares tuna catch rates with differently sized hooks (4.5 millimeter and 4.2 mm).
Baird says he’s not convinced that a 4.2 mm hook will be effective. “That said, as is obvious from the observer data, the crew are often just cutting the lines, leaving animals with a lot of trailing line that could then entangle the individual, so additional training (of crew as well as of captains, and in the various languages of the crew) is clearly needed,” he stated in an email to Environment Hawai‘i.
Earthjustice attorney David Henkin agreed that something needed to be done to prevent crews from cutting lines. “Entanglement in trailing gear is a major source of post-hooking mortality, so the fact that longliners are cutting the lines is a major concern that needs to be addressed. Moreover, cutting the lines is ultimately self-defeating for the longliners, as leaving trailing gear can increase the rate of mortality and serious injury, resulting in increased restrictions on the fishery. … [I]f the longliners simply cut the lines, that can defeat the benefits of any gear modifications,” he said.
In two of the three hookings that occurred in November, the captains cut or directed their crew to cut the lines. In the third case, the line broke as the captain maneuvered the boat to create tension on the line and straighten the hook.
Even if the fleet adopts the right combination of gear and gear handling, Baird argues that the observer effect on crew and captain behavior still needs to be addressed.
“[W]hen no observer is on board, I think they probably cut the lines much more frequently. Without electronic monitoring, particularly video monitoring of the crew behavior when a false killer whale or other protected species is on board, I think the plan, whatever its configuration, is flawed,” Baird said.
(For more background, read “Council Seeks to Quickly Reopen Area Closed Due to Whale Takes,” from our April 2019 issue, and “False Killer Whale Team Fails to Reach Consensus on New Protection Measures,” from May 2018. Both and more are available free on our website, www.environment-hawaii.org.)
— Teresa Dawson
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