Report on Cetacean Sighting Survey

Onboard the M.V. DA-BFAR In Philippine Waters 16 – 26 August 2009

Cetacean Research in Southeast Asian Waters: Cetacean Sighting Program

CFTD

Report on Cetacean Sighting Survey Onboard the M.V. DA-BFAR In Philippines Waters

16-26 August 2009

Sayan Promjinda Tossaporn Sukhapindha

Background

Even though cetaceans in the Southeast Asian waters have been focused for more than decades already, information on their distribution, composition and abundance is still unclear. This is presumed to be due to the absence of adequate sighting methodologies. Many efforts have been made to collect cetacean data/information but these are mainly through land-based observations, hotspots watching and dead specimen investigations, the resulting information of which could be very limited in terms of the spatial and temporal context. Moreover, sighting surveys by research vessels are rarely carried out because sighting methodologies for cetacean classification and population assessment techniques are not yet fully developed.

Starting in August 2008, SEAFDEC implemented a program on cetaceans in the Southeast Asian waters, which is being supported by the Government of Japan Trust Fund Program. The program aims to establish the appropriate cetacean sighting methodology; enhance human capacity for the collection of scientific information on cetacean distribution and composition in Southeast Asian waters which are fundamental for the development of techniques on cetacean classification and population assessment; and mitigate the interaction of cetaceans with fisheries. In this regard, SEAFDEC Training Department (SEAFDEC/TD) embarked on a study to conduct actual sighting survey using the SEAFDEC research vessels and available research vessels of the SEAFDEC Member Countries.

Considering that the Philippine Bureau of Fisheries and Aquatic Resources (BFAR) has a mission to conduct a marine research survey in the Philippine waters using its research vessel, the M.V. DA-BFAR, SEAFDEC requested and was granted permission for two (2) SEAFDEC/TD staff to join the survey onboard the said research vessel. The specific objectives of SEAFDEC in sending the two staff to join the Philippine survey are: to collaborate with the staff of BFAR for the cetacean sighting research survey; and to disseminate and exchange information on cetacean sighting methodology by the M.V. DA-BFAR with the BFAR scientists.

Overall Objectives

In addition to the aforementioned objectives, the study of SEAFDEC/TD on the actual sighting survey using the SEAFDEC research vessels as well as research vessels of the SEAFDEC Member Countries, specifically aims to:

- gather cetacean data/information and make a check list of cetacean species existing in the Southeast Asian waters based on data from the Member Countries as well as those collected during the actual SEAFDEC sighting surveys;

- gather information on whale/dolphin watching spots existing in the waters of the SEAFDEC Member Countries; and

- share/exchange information on the appearance of large cetaceans in the coastal areas and/or on the seashores of the countries in the Southeast Asian region.

Equipment and operation methods used in the explorations

Explorations to conduct the cetacean sighting surveys should be conducted from sunrise to sunset of each day. Primary searching is conducted when the research vessel is cruising on line under good weather conditions. Sighting data obtained during the primary searching are primary sightings only and attempts to approach the objects for species identification, school size counting, and other data collection, e.g., photographs should be carried out. Secondary searching mode is carried out when the vessel deviates from the track line for observation of the animals or runs out of line during bad weather conditions. Sightings obtained during the secondary searching mode and drifting status of the vessel, are considered as secondary sightings. During the primary searching, two or more researchers should be on duty on the upper deck or bridge of the vessel, to search for the cetaceans on the sea surface around the vessel route, especially along the course of the vessel. Searching is conducted with naked eyes and if available, with the use of binoculars (Fig. 1.). When secondary searching mode is applied, the researchers should search for the cetaceans on an opportunistic basis. Moreover, researchers must take turns in serving as recorders. The role of the recorders is to write down in appropriate sighting record (Fig. 2), the information observed and noted during the sighting and searching activities. The recorders as well as the vessel captain and crew should also search the sea surface for the presence of cetaceans.

When the presence of cetaceans is noted, efforts should be made to take the photographs of the cetaceans or schools of animals, and report the following data to other researchers on board, and specifically to the assigned recorders. Information could include the estimated radial distance, sighting angle, and cue at the same time. After taking the report, the recorder should write down the data and time/position, when/where the sighting was observed (Fig. 2.) and then, the vessel should as much as possible approach the objects.

Fig. 1. Digital D-SLR Nikon D80, Lens Nikon ED AF-S VR- NIKKOR 70-200 mm 1:2.8 G, AF-S Teleconverter TC-20EII 2X and Nikon binoculars.

Survey area The cetacean sighting survey in Philippine waters using the M.V. DA-BFAR started from Butuan City in northern Mindanao on 18 August 2009 (Fig. 3). The vessel sailed from Butuan City to Siargao Island, set one payaw at sea depth of 1800-2000 m, and conducted one Pelagic long line fishing operation at the eastern part of Siargao Island at sea depth of 7000-9000 m. After completing the activities, the M.V. DA-BFAR proceeded back to Manila, passing through the Mindanao Sea, Camotes Sea, Visayan Sea, Sibuyan Sea and along Romblon Island, then proceeded to Manila Bay, arriving on 23 August 2009. The detailed daily activities in relation to the cetacean survey onboard the M.V. DA-BFAR, are shown in Table 1.

Fig.2. Sighting record form for cetacean sighting survey

Fig. 3. Route of the sighting survey on board the M.V. DA-BFAR

Results of the sighting survey During the sighting survey, two species of whales were observed. One sperm whale (Physeter macrocephalus) was found near the coasts of Siargao Island at Latitude 9o52.30 N and Longitude 126o10.80 E and sea depth of about 1000 m (Fig. 7). The toothed sperm whale is a truly unique cetacean having its own family, Physeteridae. The whale’s bizarre shape attracts people’s attention especially the huge square head with a cavity large enough to hold a car. Sperm whale is one of the most spectacular divers, reaching up to 3 km below the surface, hunting for large squids using its spermaceti organ for echolocation in darkness. Its highly complex social organization is based on age and sex (Shirihai and Jarrett, 2006). One school of melon-headed whale (Peponocephala electra), about 10 whales in a school, was also observed while the vessel was sailing on the route line from Mindanao Sea to Camotes Sea at Latitude 9o57.60 N and Longitude 124o56.10 (Fig. 8). Most likely the melon-headed whale is confused with the Pygmy Killer Whale. It is also quite similar to the False Killer Whale but the latter is distinctly larger with different shape, bent flippers, proportionately smaller dorsal fin and more rounded head, and lacks the whitish color on its lips or white belly patch, and has different behavior (Jefferson, Webber and Pitman, 2008). Melon-headed whales are moderately robust small whales. The dorsal fin is tall and slightly falcate, and is located near the middle of the back. The head of adults can be bulbous, and the “melon” can be overhanging in adult males. However, younger animals have a more sloping forehead, although there is generally little hint of a beak. The flippers are sickle-shaped and with pointed tips. Compared to females, males have more bulbous melons, longer flippers, taller dorsal fins, and tail stocks with pronounced post-anal humps (often called keels). The range of the melon-headed whale coincides almost exactly with that of the pygmy killer whale in tropical/subtropical oceanic waters between about 40oN and 35oS. They are rarely found near shore, unless the water is very deep. A few high-latitude stranding are thought to be extralimital records, and are generally associated with incursions of warm water. A group of dolphins were also sighted when the vessel was sailing back to Manila (Fig. 6). Seven schools of dolphins were identified from the observed and pictures as Gray’s Spinner Dolphins (Stenella longirostris). However, the other groups could not be identified because only the fins could be seen or only the silhouette of the animals could be seen as they were swimming under water. The spinner dolphin is a slender species, with extremely long, thin beak. The head is very slender at the apex of the melon while the flippers are slender and re-curved. The dorsal fin usually ranges from slightly falcate to erect and triangular. In adult males of some populations, however, the dorsal fin can be so canted forward that it looks as if it were stuck backwards. The tail stock may become deepened, with an enlarged post-anal hump (sometimes called a keel) of connective tissue, and the tips of the flukes may curl somewhat upward. These three features are correlated with the development in adult males.

Gray’s spinner dolphin (Stenella longirostris) is the typical form of spinner dolphin found in most areas of the world (with the exception of some waters of tropical Asia and the eastern tropical Pacific). They have the tripartite color pattern with a falcate to triangular dorsal fin, small to non-existent post-anal hump, and relatively small dorsal fin and flippers. Tooth counts are generally in the range of 40-60 per row. Adult females are about 1.39-2.04 m long, and males are 1.60-2.08 m (Jefferson, Webber and Pitman, 2008).

Table1. Cetacean sighting data

Fig. 4. Locations of the cetaceans sighted during the survey

No. Time Date Latitude Longitude Cetaceans sighted Number 1 06:26 19-Aug-09 9 42 84 N 126 10 86 E Common bottle nose Dolphin 5 2 11:50 20-Aug-09 9 50 20 N 126 35 18 E Dolphin 3 3 17:30 20-Aug-09 9 52 30 N 126 10 80 E Sperm Whale 1 4 12:47 21-Aug-09 9 57 60 N 124 56 10 E Melon head Whale 10 5 14:07 21-Aug-09 10 06 47 N 124 45 26 E Dolphin 4 6 17:11 21-Aug-09 10 26 80 N 124 28 10 E Dolphin 5 7 1740 21-Aug-09 10 29 80 N 124 23 40 E Dolphin 10 8 11:05 22-Aug-09 12 23 20 N 122 23 40 E Spinner Dolphin 10 9 17:15 22-Aug-09 12 36 50 N 122 12 05 E Spinner Dolphin 50

Fig 1. Data recording, data collection and Photographs

Fig. 5. Data recording, data collection and photography

Fig. 6. Dolphins surfacing during calm seas, showing dorsal fin

A B C D.

Fig. 7. A. Logging sperm whale: note the very long, log-like body

B. Sperm whale has dark, wrinkled skin and triangular or rounded hump

C. The single blowhole of a sperm whale is situated at the very front of the blunt head

D. Characteristic blow angled forward and to the left

Fig. 9. Group of dolphins and calves moving at high speed and jumping

Fig. 8. Group of melon-headed whales at the surface, showing the tight social structure typical of the animals

Melon-headed whales: note the somewhat pointed head, narrow whitish lips

Fig 9. Spinner dolphin Stenella longirostris showing considerable color pattern variation

Daily activities

Date Time Activities 16 Aug 09 0905 Leave Thailand for Manila, Philippines 1320 Arrive Manila 17 Aug 09 1100 Leave Manila for Butuan city, Mindanao 1230 Arrive Butuan city

Discussion with Dr. Jonathan Dickson 1800 Aboard MV/DA-BFAR 18 Aug 09

1000 1100

Leave port for Siargao Island Discussion and briefing on the objectives and procedures of the cetacean sighting survey with researchers and crew of The M.V. DA-BFAR

1200-1800 Cetacean sighting survey 19 Aug 09 0900 Arrive Siargao Island

Coordination with payaw operators/fishermen

1400 Setting one set AFADs in Philippine Sea at the eastern part of Siargao Island then proceed to Siargao Island

20 Aug 09 0200 Shooting PLL, 500 hooks were deployed. 1000 Hauling PLL, proceed to Siargao Island 1400-1800 Cetacean sighting survey 21 Aug 09 0100 Leave Siargao Island for Manila 0500-1800 Cetacean sighting survey 22 Aug 09 0500-1400 Cetacean sighting survey 1400-1700 Alongside at port of Romblon Island 1700-1830 Cetacean sighting survey 23 Aug 09 0600-1000 Cetacean sighting survey 1000 Arrive Manila 24 Aug 09 0800 Disembark the M.V. DA-BFAR, leave for hotel 1300-1500 Discussion with Dr. Alma and Dr. Jonathan Dickson at

BFAR office 26 Aug 09 1400 Leave Manila for Thailand

Table 2. Daily activities from 16 to 26 August 2009 References Hadoram S. and B. Jarrett. 2006. Whales Dolphins and Other Marine Mammals of the World, Princeton Field Guides, 384 p Thomas A. J., M. A. Webber and R. L. Pitman. 2008. Marine Mammals of the World,

A comprehensive Guide to their Identification, 573 p