For centuries the Savu Sea provided safe passage for whales migrating from Australia to Indonesia. Today, human activities is threatening cetaceans and its habitat.
It’s been six months. Lembata Island, in East Nusa Tenggara, is getting drier as the year progresses. The sky appears to be pollution-free; it is blue, warm, and calm. That night, nua tapo, the local name for the south-pointing constellation Crux, flashed over Lamalera, a village next to the Savu Sea.
Not long after sitting on the bamboo couch, Lois Beding, 48, got up and walked over to the electricity switch on his porch. The lights are now out, as the sky resembles the ceiling of a planetarium. It was in the midway phase between the new moon and the full moon hung above the horizon before sinking slowly towards midnight, leaving the surface of the Savu Sea darker.
For centuries, the sea has been a safe passage for whales migrating from Australia to spend the winter in Indonesia’s tropical waters. Lousy weather and traditional whale hunters might have killed several whales during their migrations in the past, but never in numbers that decimated the entire mob. Today, however, modern human activities in the area come with new threats to the cetaceans and their habitats.
Stretches across 3.35 million hectares, the Savu Sea is a flourishing haven for 12 species of dolphins and four species of whales (in the cetacean infraorder), dugong (sirenian), sea turtles, manta rays, and whale sharks. Indonesia’s eastern sea contributes as much as 18.2 percent to the country’s 28 million hectares of the country’s marine protected area, according to Kupang Marine Protected Area Agency (BKKPN Kupang).
The Savu Sea borders ten districts in the East Nusa Tenggara archipelago. As many as 64.9 percent of the adult population in the ten districts make a living as fishermen, according to the BKKPN Kupang’s latest data in 2011. The agency recorded 2,495 fishing fleets spread across the ten districts in the same year.
Ferries—far cheaper than propeller-engined planes—are the mainstay of transportation for people traveling between islands. The Savu Sea is also one of three of Indonesia’s Archipelago Sea Lane Passage, a set of international shipping and flight routes designated through government regulation.
In a webinar held by BKKPN Kupang at the end of July 2022, Agus Sutrianto, the representative from Indonesia’s Navy Oceanography Center, said that “at present, some part of Indonesia’s sea lane axis overlays with the Savu Sea’s core conservation zone.”
That could pose a risk to the protected animals in the area. “We need to have a deeper study to mitigate the overlapping area between conservation, naval exercise, sea trade shipping, and transportation,” Agus said.
The cetaceans of the Savu Sea
From May to October, dozens of four species of whales used to enter the waters of Lamalera. The four species are blue whales (Balaenoptera musculus), sperm whales (Physeter macrocephalus), humpback whales (Megaptera novaeangliae), and fin whales (Balaenoptera physalus).
Each year during these five particular months, the marine mammals migrate from the Great South Australian Coastal Upwelling System to the north. Their stops include the Savu Sea.
Migrating to the lower latitudes, the distance traveled by the four species of whales is about 1,997 miles or 3,214 kilometers. It is the distance between Great Australian Bight and Rote, one of Indonesia’s southernmost islands directly adjacent to the Indian Ocean to the south.
The Savu Sea is “subject to seasonally reversing monsoon winds” due to its geographical location, according to James T. Pomtera et al. From April to November, the austral winter wind blows above the Savu Sea surface. Between December and March, the austral summer blows. The upwelling phenomenon, which some suspect to cause cetaceans to strand in the area, comes with the winter wind and “reaches its peak in June.”
Three years ago, an Indonesian news agency quoted a researcher’s statement about the factors that cause cetaceans to strand in East Nusa Tenggara. According to the researcher, one of the stranding factors was upwelling in the Savu Sea. According to BKKPN Kupang data, up to 20 cetaceans were stranded in East Nusa Tenggara in 2019.
Putu Liza Kusuma Mustika, a member of the International Union for Conservation of Nature (IUCN) Cetacean Specialist Group, had her perspective on the Savu Sea’s dynamic water mass as a stranding factor. “Could be like that. But we need much more time-series data, and we may have missed the baseline data,” said Mustika on Sep 4.
“Doesn’t mean we can’t answer that,” added the marine mammal’s researcher who lives in Queensland, Australia, “but we definitely need more research to see the trend.”
Gifts from the Lord
Fishermen in Lamalera have traditionally “taken the Lord’s blessings” by sailing the waters in front of their village in search of large marine species. Instead of “capturing,” they see the process as an attempt to “accept gifts from God.” The people of Lamalera believe that they are not grateful if they “do not accept the blessings.”
“Traditional whaling in Lamalera has quite a few dimensions,” said Firdaus Agung, Director of Marine Conservation and Biodiversity, Ministry of Marine Affairs and Fisheries. From a regulatory perspective, cetaceans that enter the waters of the Savu Sea are protected animals.
“Meanwhile, by the people of Lamalera, catching cetaceans is considered a traditional practice,” said Agung.
Administratively, Lamalera village is included in the Wulandoni sub-district. According to data published by the Ministry of Villages, Development of Disadvantaged Regions, and Transmigration, 9,020 people lived in Wulandoni in 2021. There is no official data on the exact number of Lamalera villagers. On its website, the ministry only lists 25 neighborhoods in Lamalera.
Instead of indigenous people, Lamalera people identified themselves as ordinary communities who have obeyed the customary law since the time of their ancestors. In Indonesia, the determination of a community with the status of “indigenous people” must pass through certain stages regulated by the local government until their relevant regulation ratifies it.
During the hunting season, the fishermen are out for all cetaceans, including dolphins (Delphinus delphis), spinner dolphins (Stenella longirostris), and their most valuable valued prey, whales.
The blue whale is the largest whale species and, like the sperm whale, is most often seen in the Savu Sea during the months of migration, Lamalera fishermen said. But, no villager of Lamalera can hunt blue whales. According to their folklore, a blue whale once saved a tribe in Lamalera. Since then, the people have deemed the species sacred and off-limits to hunters.
The Beding family has traditionally been fishing in the Savu Sea. One small boat or peledang can carry four to five fishermen. “Most often [a boat] is taken by brothers,” said Ignasius Praso Beding, one of Lois’ younger brothers as he continued, “or cousins from the same lineage.”
Ignasius said five years ago, they could catch up to 20 cetaceans. Once they have caught a cetacean, all that remains is to secure it with a hawser.
The long journey home starts, as they sing songs of mother sea. “The singing and the hollow, rhythmic beating of the paddles can be heard all over the village,” wrote R.H. Barnes in his book, Sea Hunters of Indonesia – Fishers, and Weavers of Lamalera.
Every return home is a whole village’s happiness. Men will gather onshore, waiting for every boat to come closer to the beach. Then they cut the body of the catch to be distributed to the entire village. Widows and orphans get the first cuts. But it’s different now.
“Last May, only four sperm whales entered the waters of the [Lamalera] village,” said Lois. The Lamalera people believe that the lack of cetaceans resulted from “the sins accumulation of the whole village.”
After May, not a single whale was seen swimming around Lamalera. The blue whales have also vanished.
Tracking the wandering ways of the whales
Last November, several researchers embarked on an expedition in the waters close to Rote Island, about 270 kilometers to the southwest of Lembata Island. Rote is situated south of the Savu Sea and is one of Indonesia’s southernmost islands, directly connected to the Indian Ocean.
The expedition aimed to track whales’ migration. The researchers managed to pin tagging devices on the bodies of two blue whales and a koteklema, the local’s name for sperm whales.
“Last November was our first tagging project,” said Jaya Ratha, a cetacean stranding evacuation trainer who actively participates in Whale Stranding Indonesia, a community that tracks and maintains a database of marine mammal stranding events in the archipelago.
Jaya participated in the Coral Reef Rehabilitation And Management Program-Coral Triangle Initiative (Coremap-CTI), a reef rehabilitation program managed by the Indonesia Climate Change Trust Fund (ICCTF) and the National Development Planning Agency (Bappenas) in collaboration with BKKPN Kupang and other stakeholders in Savu Sea National Park. The partnership involved Kupang-based stakeholders and cetacean researchers to update the cetaceans’ migration data.
Their first attempt at tagging met with various challenges. Jaya and his colleagues sailed the waters of the Savu Sea for at least two weeks in the months when the eastern sea of Indonesia began to rain. “That November, none of the researchers on board the ship had a success in tagging,” said the veterinarian who now lives in Bali.
To apply the tag, researchers had to wait for a whale to come to the surface to breathe. The ideal encounter, Jaya continued, “is when the whales are busy eating or taking a short nap at sea level.” However, even at times considered ideal, the effort to embed the tool also requires a much more complicated.
The tagging tools, like a bow and an arrow, should be shot from an ideal distance of at least four meters in calm water conditions. When Jaya was involved in the tagging effort, Savu’s sea level was high. For days their ship often tossed about, succumbing to being hit by high waves often accompanied by strong winds.
It’s natural that once a shot misses the target and the tool falls into the sea, “we immediately get dizzy,” he said with a chuckle, “remembering the price of the tools that we have been using.” The price of the arrow itself is around Rp 25 million ($1,678), roughly equal to what a typical Lamalera fisherman makes in a year.
Once the device fell into the sea, “it also means that we can’t get the data. Well, I can say it would be a huge disappointment,” said Jaya on June 25.
Jaya said he was grateful because for two weeks—while waiting for the ideal shooting distance between the tagging tool and the whale—he could observe the marine mammal’s behavior. “It was great to see it swimming under the clear sea surface before breaking into the water, popping up just to breathe,” said Jaya.
On that cloudy morning, Jaya showed three whales’ migration routes. The device embedded in the koteklema body only lasted about a week. While on the two blue whales survived up to two months later.
“Early last June, one of them was detected around Rote Island,” said Imam Fauzi, the head of the BKKPN Kupang. Generally, during the May-October migration season, a whale swims from the south of the Australian continent to the north, passing the water of the Savu Sea.
More than 30 species of marine mammals migrate through Indonesian territorial waters. Through a regulation issued in 1999, the government stipulates that all marine mammals are protected in Indonesian territorial waters.
In 2018, The International Union for Conservation of Nature (IUCN) listed blue whales as endangered. The blue whale population worldwide is less than 15,000. The eastern part of Indonesia has been the blue whales’ migration route for years.
“Their passage within our territorial waters is not always a safe journey,” IUCN’s Liza said.
Marine debris, ship hulls, fishing nets, and the sea’s noise pollution “are some factors that threaten their migration. Marine debris is the biggest factor here.” The human-based activities she mentioned “could, in some way, deviate their migration route and make them stranded, near or far off the Savu Sea.”
Meanwhile, on two blue whales tagged by Jaya and his colleagues, “it is possible they went somewhere near Lembata before moving to the Banda Islands,” BKKPN Kupang’s Imam said. The Banda Islands, which are included in the administrative area of Maluku Province, are 22 hours of traveling by boat to the northeast of Lembata.
He did not rule out the possibility that the blue whales’ journey had shifted to the east rather than the north since crossing Rote Island. “It’s also possible that they went to the Arafura Sea instead of Lembata Island,” Imam said.
As the head of the Savu Sea’s marine protected area—a section of the sea where the government limits human activities to protect marine life— Imam felt compelled to find out the cause of the whales’ behavior changes.
His initial findings led him to suspect two new factors in whales’ migration disruption: seismic survey activities and submarines passing through the conservation area.
Give cetaceans more time to pass the sea
A seismic survey is one of the initial stages in underwater oil and gas exploration. The survey utilizes sound waves as the primary information medium for obtaining underwater images, similar to submarines using sonar for underwater navigation or whales for communication, navigation, and hunting.
Several tools are used in seismic surveys, including air gun arrays, gun controllers, recording systems, and streamers. The four tools are “an integral system to, in the end, gather information based on sound waves reflected from under the sea,” Hadi Wijaya, head of West Java-based Marine Geological Institute (MGI) of Geological Agency at the Ministry of Energy and Mineral Resources, told the Globe in an interview on Aug 11.
It was Hadi’s third day as the head of his office. “This is my first time being interviewed by the media,” he said with a smile.
Still, Hadi was reserved about the notion that the seismic surveys disrupted the whales’ migration pattern. He said that seismic surveys generally involve the marine mammal observer (MMO).
At least three MMOs are onboard the seismic survey vessel. The three are divided into “four-hour shifts working continuously to monitor the possible presence of marine mammals within a 500 meters diameter zone around the center of the onboard airgun arrays,” Hadi said.
Airgun detonation, he continued, “should be delayed until the exclusion zone is clear of cetaceans and sea turtles as late as 30 minutes later.” When asked about the presence or absence of MMOs in each seismic survey, Hadi replied: “We don’t know for sure because of the data confidentiality of the seismic survey conducted by many companies.”
Seismic surveys are conducted so companies operating in the oil and gas sector can obtain images of underwater sediments. In that way, they can narrow down their oil and gas exploration activities within a few places, which, in turn, will help cut their operational costs.
In seismic surveys, the airgun—a tube-wave shaped with a valve—will be opened at a certain period to produce a sound explosion. Hadi said that “the output frequency of the airgun is around 3-200 Hz.” The output sound intensity is between 15-24 decibels (dB), a range that “is common for rustling leaves or human breathing,” he said.
Still, many scientists have sounded the danger of seismic surveys to marine animals in the past decade. John Robert Potter et al. wrote that the characteristics of the seismic signal “are poorly understood.”
There is often insufficient data to identify, but “these uncertainties are modest compared with those associated with biological factors.” Potential biological effects of air gun noise include “physical or physiological effects, behavioral disruption, and indirect effects associated with altered prey availability,” they wrote in their 2003 study.
Research findings by Ross Compton et al. further detailed the possible impacts of underwater noise sources on whale behavior and physical damage, including damage to body tissues resembling decompression sickness and auditory impairment. Decompression sickness symptoms “may result from the initiation of bubble growth caused by sound,” they wrote.
In light of the dangers, BKKPN Kupang’s Imam called for closer collaboration between institutions in managing seismic surveys in the Savu Sea.
“We need to have a deeper coordination with other ministry offices, independent veterinarians, and many more researchers from various fields of work,” said BKKPN Kupang’s Imam. They can “minimize the negative impacts of seismic surveys on cetaceans.”
Imam frequently sails between islands in East Nusa Tenggara to monitor human activities threatening the cetaceans’ passages. He hopes the Savu Sea will always be a safe place for marine biota and their ecosystem and for humans who throw light on the vast sea of Savu as their life’s source and purpose.