Keahole Kampachi Cages Attract Aggressive Bottlenose Dolphins

Bottlenose bullies.

That pretty much describes the behavior of some of the bottlenose dolphins that frequent the waters near Makako Bay, just north of the Kona airport.

Up until about 2006, most of the dolphins in the area were the much smaller spinner dolphins. Makako Bay had been used by the spinners as a daytime resting area, with up to 90 percent of the Kona spinner dolphins using it, according to Robin Baird of the Cascadia Research Collective. Baird has been studying false killer whales and other marine mammals in the area for the last couple of decades. He described his work on the bottlenose dolphins at this year’s conference on Hawai‘i ecosystem research organized by Stanford University’s Peter Vitousek, held virtually in early July.

Starting around 2006, shortly after an open-ocean fish farm had been installed in the area, one or two bottlenose dolphins began hanging around the farm’s giant net cages off of Keahole Point, Baird said. The farm raises amberjack fish, also known as kahala and sold as kampachi, with each of the cages holding thousands of the fish. At times, Baird said, there might be seven or eight bottlenose dolphins in the area.

Research cruises led by Baird have encountered bottlenose dolphins 31 times in close proximity to the fish farm and have logged 18 more encounters of bottlenose dolphins within five kilometers of it. Altogether, 35 individuals have been documented at the fish farm, both males and females, by Baird and his team. This, he said, suggests that the fish farm is attracting ever more bottlenose dolphins.

The bottlenose dolphins belong to one of four stocks around the Main Hawaiian Islands. The population for the Hawai‘i Island stock is thought to number about 136.

Early on in the fish-farm operation, workers would feed the dolphins, Baird said, citing a report from Neil Sims, one of the farm’s executive officers at the time. While that practice has ended, the bottlenose dolphins continue to hang around the aquaculture facility.

Over time, the behavior of these farm-associated bottlenose dolphins has become more aggressive, Baird said, not only toward the spinners, but also toward false killer whales. “They try to get food from false killer whales,” he said, and, in one observed instance, attempted to separate a false killer whale calf from its mother.

The fish farm, Baird suggested, represents a fixed food source for the bottlenose dolphins, reducing the amount of time they spend foraging. At the same time, their aggression toward spinners seems to have caused the spinners to abandon their resting area at Makoko Bay.

In a 2013 paper, Sims speculated that the bottlenose dolphins “are probably attracted to the fish farm by a combination of: (i) the presence of the midwater structures acting as a fish aggregating device and the associated fish community that is present around the net pens; (ii) the occasional provisioning from ‘leakage’ escapes when divers enter or exit a net pen and from the rare larger escape incidents when predators have breached the Dyneema nylon webbing; and (iii) interaction with divers outside of the net pen, as the divers move about the farm from boat to net pen and back.”

But more recently, divers have discovered the animals managing to open the pens and allow the fish to swim out – into the welcoming jaws of the dolphins.

Divers who frequent the area have caught this on videos posted to the web. One of them, Dylan Currier, has explained the action this way: “This pod claims an offshore fish farm as their territory and has developed an inge- nious method of harvesting their own percentage of the catch. The dolphins swim down below the rim of the cage where there are holes in the net and use blasts of air to scare the jacks out into the open.”

Baird said until the observations of the bottlenose dolphins around the fish farm, he had never seen bottlenose and spinner dolphins together. “All aggressive behaviors,” he said, “involved farm-associated dolphins.”

A few kahala manage to escape both cages and the bottlenose dolphins. At the June meeting of the Western Pacific Fishery Management Council, council member Ed Watamura, a fisherman, said that the escaped kahala are “barraging everything.” Fishers targeting bottomfish “have to pick up and move” when the kahala come along, he said. “After catching 10 or 12 kahalas, you give up.”

“Many bottomfishermen are saying the same thing,” he added. “The escapees are a problem. And we know it’s the result of escapees. There are two types of kahalas. The one’s we’re catching more of are the aquaculture kind.”

Wespac Advisors Critical Of Measures to Protect False Killer Whales

At the June meeting of the Western Pacific Fishery Management Council, members heard Jim Lynch, chairman of the council’s Scientific and Statistical Committee, lay out a proposal that certain members of the SSC had been developing. The informal working group – consisting of Lynch, retired social scientist and longtime SSC member Craig Severance, Australian environmental consultant Milani Chaloupka, and David Itano, a former fisheries biologist with the National Marine Fisheries Service and now a consultant in private practice – had come up with an outline of what Lynch and the others hoped would eventually be an article in a peer-reviewed scientific journal discrediting the several measures imposed on the Hawai‘i- based longline tuna fishery to reduce its impact on false killer whales.

At the SSC meeting held the previous week, Lynch had unveiled the group’s
work to the rest of the committee. “Some of us have seen a lack of action,” he said, when it came to reducing the impacts of fishing on false killer whale populations. “The SSC’s recommendations have not been taken into account. The paper we developed attempts to synthesize years of data and recommendations” that could be forwarded to the council and the National Marine Fisheries Service.

“The goal and intent is to produce one or more scientific presentations that can be presented to journals,” Lynch said. The paper or papers could then be used by the agencies “to address impacts to false killer whales in a lawful and pragmatic way.”

Each member of the working group was assigned a section to work on. Although the draft paper was distributed to other members of the SSC who weren’t included in the working group, it was not made public.

A summary of the group’s preliminary conclusions was presented in outline form, however. Among other things, the group had:

• reviewed “a decade of interaction research and mitigation efforts;

• taken note of previous SSC and council recommendations (“both those followed and ignored!”);

• reviewed gear modifications, seeing “promise in the industry-led switch” to monofilament leaders; and

• taken note of the fact that under the federal Marine Mammal Protection Act, the development of PBR – potential biological removal – “drives the process, but does not encourage creative solutions. (PBR is the maximum number of animals that can be removed from a defined population while still allowing that population to reach its optimum level.)

Several approaches to mitigation that have either been adopted or are now being studied were pooh-poohed. A proposed “move-on strategy,” requiring vessels that encounter false killer whales to relocate to different fishing grounds, is “inappropriate for a fishery marketing fresh, iced product with limited storage time,” the working group found.

“Catch-shielding gears,” to protect caught fish from depredation by false killer whales, “have many logical issues,” while “acoustic deterrents can become ineffective and contribute to the ‘dinnerbell’ effect,” the group determined. Like the move-on strategy, these two approaches have merely been floated as possible deterrence measures.

Three additional mitigation measures that are either required or are being studied are the use of weak hooks (allowing the animals to free themselves when the line is held taut); cutting branch lines close to the hook, and thus minimizing trailing gear when the animal is set free; and “novel line-cutting devices.”

The last of these is actually in development by the Hawai‘i Longline Association, in connection with its switch to monofilament leaders on all deep-set longline (tuna-targeting) fishing vessels. This approach, the group concluded, “should be promoted.”

As for weak hooks, their use is the subject of an ongoing study, whose results are expected to be released later this year.

The group was skeptical about the utility of cutting branch lines closer to the hook. This “should be better assessed in relation to post-release condition and serious injury determinations,” the group found.

Chaloupka’s presentation was the harshest.

The false killer whales are “abundant and widespread in the Pacific,” he said, with both the insular populations of the animals as well as their pelagic counterparts exposed to anthropogenic hazards around Hawai‘i. They are not at “high risk” of capture by the Hawai‘i fleet, he added, and there’s no evidence of a “high apparent rate of at-vessel mortality” for animals taken in the fishery.

He continued. There is no “reliable information” on captures and at-vessel mortality “readily available for monitoring status and trends;” no reliable estimate of post-release mortality and sublethal effects for animals caught by longliners; no “reliable demographic parameters … needed for stock assessment and diagnosing trends;” no “level-4 population consequences of distribution- based risk assessment;” and no evaluation of the effect of the Southern Exclusion Zone or weak-hook rules.

“So,” he concluded, “is an evidence-informed bycatch mitigation policy in place? No.” It is, he added, “a unicorn.” To which council executive director Kit- ty Simonds replied, “Amen, brother.”

Another SSC member then asked him, “What’s a unicorn?”

“A figment of your imagination,” Chaloupka responded.

The group came up with six recommendations, including several that seem at odds with each other.

Recommendation three calls for additional studies of false killer whale population dynamics. The fourth recommendation suggests that a new metric, other than PBR (potential biological removal) be developed to assess trends in the false killer whale population.

The fifth recommendation calls for elevating the role of the Scientific and Statistical Committee in developing measures included in the Take Reduc- tion Plan for false killer whales. The friction between the False Killer Whale Take Reduction Committee, charged with reducing the interactions between

the protected animals and the longline fishery, and the SSC goes back years. It broke into the open in January 2014, when Robin Baird, who sits on the TRT and who, at the time, was on the council’s Protected Species Advisory Committee, was disparaged by Chaloupka when Baird was making a presentation to the SSC.

Baird pioneered research into false killer whale populations in waters sur- rounding the islands in the Hawaiian archipelago, and it was largely his work that was responsible for listing the insular population, around the Main Hawaiian Islands, as an endangered distinct population segment under the federal Endangered Species Act. Baird also sits on the Take Reduction Team.

As reported in Environment Hawai‘i in the March and May 2014 editions, Baird was so outraged by the conduct of Chaloupka that he resigned from the council advisory committee and walked out of the meeting.

The final recommendation is that the council adopt “conformance-based monitoring” of false killer whale cap- tures. What exactly this means was not explained.

Lynch made the same presentation to the full council the following week. Council members praised the report.

Ed Watamura: “Just wanted to say hallelujah, Jim. … You guys, everything you’re doing is what I’ve been thinking about.”

McGrew Rice was also thrilled: “This is the most exciting part of the meeting for me. I’ve been on the trail of false killer whales for the last nine years. Good to see you guys are putting it on paper.”

Mike Tosatto, administrator of NMFS’ Pacific Islands Regional Office, praised the group’s work as well.

“I say that with sincerity,” Tosatto continued. “I can commit, we have a MMPA structure. … I wouldn’t char- acterize it as a failed act, but it can be improved, catch up to the times. The MMPA has many benefits, but it also has many unfortunate statutory require- ments. We have to follow them.”

He noted that the council operates under the Magnuson-Stevens Act, “updated every ten to fifteen years. The MMPA is stuck in the past. The obligation of the Take Reduction Team is well defined as reducing PBR [potential biological removal] but we have to get to near zero. That’s not necessarily the same objective as the council has.”

Lynch replied that he, too, tried to educate SSC members about the con- straints of the law. “But it doesn’t stop there,” he said. “We need to educate everyone. We owe it to ourselves to not just be complacent but challenge things that don’t make sense.”

Toxoplasmosis, Rain, And Dying Monk Seals

The relation between toxoplasmosis, feral cat colonies, and monk seal deaths has been well established. In recent years, 13 monk seal deaths have been attributed to toxoplasmosis, a disease caused by a parasite shed in cat feces.

But scientists at the Pacific Islands Fishery Science Center have also been observing monk seal strandings (including deaths) that seemed to happen after rainy periods.

As explained in the science center’s recent report to the council, “we set out to formally study the association between toxoplasmosis strandings and major freshwater runoff events that might flush oocysts [similar to eggs] into the monk seals’ coastal habitat.”

PIFSC researchers’ initial findings “indicate that cases were up to 35 times more likely than controls to occur a few weeks after heavy runoff events. The greatest odds ratio was observed when rainfall occurred three weeks prior to stranding, potentially providing clues about the timeline of the disease process.”

The heavy rainfall events, the researchers noted, deliver “sufficient numbers of oocysts to infect Hawaiian monk seals. With infectious doses as low as a single oocsyst, any contaminated runoff constitutes a serious risk to Hawaii’s endangered monk seals.”

The researchers conclude, “This analysis indicates, as has been documented in other marine species, that land-to-sea flow of oocysts locally is the main source of exposure for Hawaiian monk seals and suggests that local to regional scale efforts to mitigate oocyst deposition and runoff can reduce risk of exposure to this devastating disease.”

— Patricia Tummons

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