dugongs in palau - C3
dugongs in palau - C3 dugongs in palau - C3
Spatial distribution A total of 27 individuals were counted during the course of the 2003 survey, seven of which were calves. As in previous years, the highest concentration of dugongs was found in the Malakal Harbor area. Most sightings in the northern waters of Babeldaob occurred in the western lagoon, close to the states of Ngatpang and Ngardmau. Only one individual was see n on the eastern side of Babe ldaob. In all previous aerial surveys, with the exception of 1983, the Malakal Harbor area (see segment s I, II and VII on Figure 5) has been identified as an important habitat for dugongs, with the greatest concentrations of animals being observed here. Typically, 35-60% of the total animals recorded were seen in this area. The earliest surveys (1977, 1978 and 1983) were not compared in Table 3 because of differences in aircraft, longer flight tim es (up to 2-3 times the length of later surveys) and/or number of times each segment was surveyed (between 1 and 9 times in earlier survey compared to 1-3 times in later surveys). Only 7.7 % of dugongs observed in the 2003 flight wer e in shallow water (where the bottom was visible) and this is consistent with Marsh’s observations in the 1991 survey, when all but 8 % of dugongs were seen in deep water (Marsh et al., 1995). Most dugongs are found in segments I – II, (Malakal Harbor and north-east of Ngel Channel towards Airai) and V-VI (Ngardmau Bay and the western lagoon). No dugongs have been seen north of Ngerchelong except for a mother and calf pair sighted in Kossol Lagoon in 1998. Few dugongs have been seen south of the Malakal Harbor area, with no sightings recorded south of Mecherchar in the waters of Peleliu or Angaur. However, in 1978 and 1983, six individuals were seen in the southern sections of VIII, IX and X. These observations may have been due to increased flight times (up to twice as long). The aerial sightings for these three survey years are displayed in Figure 6. No. of Dugongs Adults—Calves % of Total Dugongs Counted Segment 1991 1998 2003 1991 1998 2003 I 3—1 3—1 3—1 15.4 12.1 14.8 II 1—1 13—2 9—3 7.7 45.5 44.4 III 2—0 0—0 1—0 7.7 0 3.7 IV 1—0 0—0 1—1 3.8 0 7.4 V 4—0 2—2 3—1 15.4 12.1 14.8 VI 10—2 5—0 1—0 46.2 15.2 3.7 VII 1—0 1—0 0—0 3.8 3 0 VIII 0—0 1—1 1—1 0 6.1 7.4 IX 0—0 0—0 0—0 0 0 0 X 0—0 0—0 1—0 0 0 3.8 XI 0—0 1—1 0—0 0 6.1 0 XII 0—0 0—0 0—0 0 0 0 Sub-Totals 22—4 26—7 20—7 TOTAL 26 33 27 Table 3: Relative distribution of dugongs in aerial survey segments (Figure 5). Segments which >10% of the total number of dugongs were sighted have been highlighted. in 9
XII XI IV V VI III VII II IX VIII X I Figure 5: Map showing the twelve aerial survey sections used for measuring dugong distribution in Palauan waters (After Brownell et al., 1981). 10
- Page 1 and 2: current status of knowledge of dugo
- Page 3 and 4: ACKNOWLEDGMENTS I would like to ack
- Page 5 and 6: EXECUTIVE SUMMARY This report summa
- Page 7 and 8: Palau Ι 0 7º 20' N W ESTERN P ACI
- Page 9 and 10: Incidental sightings system: The Pa
- Page 11 and 12: Flight Route 1 (flown 10-Mar-03) Fl
- Page 13: Year: 1977 1 1978 1 1983 2 1991 3 1
- Page 17 and 18: have been any drastic changes in ca
- Page 19 and 20: 2.4 Additional Information The foll
- Page 21 and 22: Ngeremlengui Ngchesar Ngiwal Large
- Page 23 and 24: Present use The majority of intervi
- Page 25 and 26: Reported sightings Prior to the est
- Page 27 and 28: Preliminary surveys The sel ected s
- Page 29 and 30: Figure 11: Transects for Ngesekesau
- Page 31 and 32: Syringo dium isoetifolium, and Halo
- Page 33 and 34: isoetifolium, and H. uninervis. The
- Page 35 and 36: 4.4 Additional Information Diet In
- Page 37 and 38: 6. RECOMMENDATIONS 6.1 Update on Ma
- Page 39 and 40: • Through a reward system, member
- Page 41 and 42: 7. REFERENCES Anderson, P.K. (1986)
- Page 43 and 44: PCS (2003) National Biodiversity St
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Figure 5: Map show<strong>in</strong>g the twelve aerial survey sections used for measur<strong>in</strong>g dugong<br />
distribution <strong>in</strong> Palauan waters (After Brownell et al., 1981).<br />
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