03 Nov CTC Conducts Cetacean Survey in Banda and Seram Seas

First Person Account by Agustin Capriati and Benjamin Kahn

More than a half of cetacean species are classified as vulnerable, endangered, and critically endangered on the IUCN Red List. This is due to many factors, mainly by anthropogenic activities such as entanglement in fishnets, marine pollution, the victims of marine-military activities or even killed indirectly by marine debris. Their slow growth and reproduction rate make them extremely vulnerable. Even so, their status including stock, habitat, as well as their behavior are still an enigma—remaining unknown, poorly understood and lack of data recorded. In addition, the logistical challenges of finding and studying cetacean and oceanic species in particular can be daunting. Therefore, the rapid ecological assessment (REA) is needed to start to address the data deficiency and fill in the information gaps.

For the third year in a row, CTC and APEX Environmental have joined expertise and successfully conducted a REA for cetaceans in Maluku, in close collaboration with the Fisheries and Marine Science Department from the Maluku Province. The team this year was once again led by Benjamin Kahn, and its members included Ali Tamher and Agustin Capriati.

We got ready for our journey to survey cetaceans, starting in Ambon and covering parts of the Banda and Ceram Seas, on 3-9 November 2018. Key Areas of Interest included West Ambon, Piru Bay, the Manipa Strait (a major migratory corridor with several clusters of seamounts), Ambalau, Southeast Buru, Kelang, and West Ceram waters. This year’s survey was supported by a grant from the National Geographic Society, with substantial in-kind support from both CTC and APEX Environmental.  

It was a sunny day when our survey boat headed out to the sea. We spent hours and hours under the scorching sun, sitting and standing from the forward deck or the aft of the boat. Using binoculars, we investigated the sighting clues to find exotic marine mammals.

“Eleven o’clock … eleven o’clock!” Ali shouted. All team members understood that was code that Ali spotted a cetacean at the eleven o’clock direction (twelve o’clock being straight ahead, six o’clock being directly behind the boat). We grabbed our camera to record species identifications, individual markings and behaviors, and came to the front of the boat. Next, the vessel’s speed, and the course was carefully adjusted to allow close observations. After some observation time, Benjamin identified and explained that it was a dwarf sperm whale—Kogia sima. These whales are one of the smallest whales on our planet and rarely sighted due to shyness around boats. We could not believe what we just saw. First encounter of a cetacean species of the day.   

Over seven days, in addition to the dwarf sperm whale, the team also identified spinner and spotted dolphins, Fraser’s dolphins, bottlenose dolphins (oceanic form), rough-toothed dolphins, melon-headed whales, pilot whales, the mysterious Cuvier’s beaked whale (a deep-diving whale, often associated with seamounts), and other marine animals. The team also recorded the distribution and density of marine debris (aggregations or “fields” of plastic waste) during the survey. Building on the previous surveys, we confirmed that the Ambon and Ceram seas are indeed important habitat areas for many species of marine mammals. Importantly, we collected data in new regions previously unknown, and added several new species to the exceptional cetacean diversity of these waters. Our survey also indicated that marine debris is a serious potential threat to these vulnerable and long-lived animals. However, it is unclear how the plastic trash may impact the marine mammals in the Banda Sea, or how they might respond to other changes in their environment in the future. Therefore, long-term monitoring is required as a prerequisite for effective management and conservation planning in Maluku waters.  

The need for additional surveys, research and conservation action on oceanic whales and dolphins was highlighted recently when a dead sperm whale was stranded on a beach in Wakatobi (southern Banda Sea) during the same month as our field work. Sperm whales are relatively common species in Indonesia’s deep ocean waters. They exclusively feed on deep-sea prey, mostly squid at depths of 600-800 m and do not forage at the surface at all. Nonetheless, this particular sperm whale animal was found to have ingested approximately 6 kg of various plastic items.

Our team is in the process of analyzing the data gathered from the survey and will post more updates soon.