Marine mammal strandings in the Philippines from 2019 to 2020

Abstract

Stranding of marine mammals is complex and understanding this phenomenon requires continuous surveillance, monitoring, data collection and research. The Philippine Marine Mammal Stranding Network (PMMSN) has collected 1178 records of stranding events nationwide from 2005 to 2020. This Technical Report is a follow-up to the second Report (i.e., Aragones and Laggui 2019). As stated in the second Technical Report the consequent series of Reports will cover two-year periods only. Thus, this third Report covers the stranding dataset from 2019 to 2020. However, as in the first (Aragones et al. 2017) and second Reports, updates on the general trends for the larger data set (2005 to 2020) will also be provided.
This Report showcases analyses of the stranding records from 2019 to 2020 (n=220) for trends in stranding frequency by year, region, season, monsoon, species, sex, age class, original disposition, release and rehabilitation success. The spatial coverage presented in this report was specific to regions and provinces primarily for administrative purposes. Identification of more specific or smaller spatial areas (i.e., by municipality/city) for potential stranding hotspots was assessed using Fishnet Tools (using 15 x 15 km grids). Furthermore, seasonality of stranding events was categorized according to the prevailing monsoons. The Northeast (NE) monsoon months are November to February (NDJF), Southwest (SW monsoon) monsoon months are June to September (JJAS), and Spring Inter-monsoon (Spring IM) in October (or Lull before NE monsoon) and the Winter Inter-monsoon (Winter IM) from March to May (MAM, or Lull before SW monsoon). The stranding data was also presented in the more classic seasonal context of DJF, MAM, JJA, SON. As data analytics advances, future reports will be improved further.

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Marine mammal strandings in the Philippines from 2019 to 2020

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Marine mammal strandings in the Philippines from 2019 to 2020

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Marine mammal strandings in the Philippines from 2019 to 2020
TABLE OF CONTENTS
Table of Contents ................................................................................................................................... 3
List of Figures .......................................................................................................................................... 4
List of Tables ........................................................................................................................................... 7
Acknowledgements ................................................................................................................................ 8
EXECUTIVE SUMMARY ........................................................................................................................... 9
INTRODUCTION .................................................................................................................................... 11
METHODS ............................................................................................................................................. 12
RESULTS ................................................................................................................................................ 13
General trends of stranding events in the Philippines .................................................................... 13
Region I (Ilocos Region) ................................................................................................................. 25
Region II (Cagayan Valley) ............................................................................................................ 31
Region III (Central Luzon) .............................................................................................................. 37
Region IV-A (CALABARZON) .......................................................................................................... 43
Region IV-B (MIMAROPA) ............................................................................................................. 49
Region V (Bicol Region) ................................................................................................................. 54
Region VI (Western Visayas) ......................................................................................................... 61
Region VII (Central Visayas) .......................................................................................................... 67
Region VIII (Eastern Visayas) ......................................................................................................... 73
Region IX (Zamboanga Peninsula) ................................................................................................ 79
Region X (Northern Mindanao) ..................................................................................................... 85
Region XI (Davao Region) .............................................................................................................. 91
Region XII (SOCCSKSARGEN) ......................................................................................................... 97
Region XIII (Caraga Region) ........................................................................................................ 103
BARMM (Bangsamoro Autonomous Region in Muslim Mindanao) ........................................... 109
DISCUSSION ........................................................................................................................................ 115
Fishnet Tool - Identified hotspot municipalities/cities .................................................................... 115
The REGIONAL hotspots in 2019-2020 ............................................................................................ 115
High annual stranding frequencies recorded in 2019-2020 – Part of Plateau ................................ 116
Species composition & the critically endangered dugong .............................................................. 116
Refloat/Release and Rehabilitation ................................................................................................ 116
SUMMARY .......................................................................................................................................... 117

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Marine mammal strandings in the Philippines from 2019 to 2020
References .......................................................................................................................................... 119
Appendix ............................................................................................................................................. 121
Plates .................................................................................................................................................. 122
A COLLECTION of Marine Mammal Stranding Photos for 2019 .................................................... 122
A COLLECTION of Marine Mammal Stranding Photos for 2020 .................................................... 135
LIST OF FIGURES
Figure 1. Number of strandings within each 15 x 15 km grid using 2005-2020 dataset. ..................... 15
Figure 2. Stranding events recorded from 2005 to 2020. ..................................................................... 17
Figure 3. Categories of strandings in year 2019 to 2020. ..................................................................... 17
Figure 4. Disposition of stranded marine mammals from 2019 to 2020. ............................................. 18
Figure 5. Age class of stranded marine mammals from 2019 to 2020. ................................................ 18
Figure 6. Sex of stranded marine mammals from 2019 to 2020. ......................................................... 19
Figure 7. Stranded marine mammal species from 2019 to 2020. ......................................................... 20
Figure 8. Stranding frequency per region from 2019 to 2020. .............................................................. 21
Figure 9. Stranding frequency per province from 2019 to 2020. .......................................................... 22
Figure 10. Stranding frequency by monsoon by region from 2019 to 2020. ........................................ 23
Figure 11. Stranding frequency by season by region from 2019 to 2020. ............................................ 24
Figure 12. Distribution of strandings from 2019 to 2020 in Ilocos Region............................................ 26
Figure 13. Number of strandings within 15 x 15 km from 2005 to 2020 in Ilocos Region. ................... 27
Figure 14. Strandings per province from 2019 and 2020 in Ilocos Region. ........................................... 28
Figure 15. Monsoonal distribution of strandings from 2019 and 2020 in Ilocos Region. ..................... 28
Figure 16. Seasonal distribution of strandings from 2019 and 2020 in Ilocos Region. ......................... 29
Figure 17. Monthly distribution of strandings from 2019 and 2020 in Ilocos Region. .......................... 29
Figure 18. Stranded marine mammal species from 2019 and 2020 in Ilocos Region. .......................... 30
Figure 19. Stranding event categories from 2019 and 2020 in Ilocos Region. ...................................... 30
Figure 20. Distribution of strandings from 2019 to 2020 in Cagayan Valley Region. ........................... 32
Figure 21. Number of strandings within 15 x 15 km from 2005 to 2020 in Cagayan Valley Region. ... 33
Figure 22. Strandings per province from 2019 and 2020 Cagayan Valley Region. ............................... 34
Figure 23. Monsoonal distribution of strandings from 2019 and 2020 in Cagayan Valley Region. ..... 34
Figure 24. Seasonal distribution of strandings from 2019 and 2020 in Cagayan Valley Region. ......... 35
Figure 25. Monthly distribution of strandings from 2019 and 2020 in Cagayan Valley Region. .......... 35
Figure 26. Stranded marine mammal species from 2019 and 2020 in Cagayan Valley Region. .......... 36
Figure 27. Stranding event categories from 2019 to 2020 in Cagayan Valley Region. ......................... 36
Figure 28. Distribution of strandings from 2019 to 2020 in Central Luzon Region. .............................. 38
Figure 29. Number of strandings within 15 x 15 km from 2005 to 2020 in Central Luzon Region. ...... 39
Figure 30. Strandings per province from 2019 and 2020 in Central Luzon Region. .............................. 40
Figure 31. Monsoonal distribution of strandings from 2019 and 2020 in Central Luzon Region. ........ 40
Figure 32. Seasonal distribution of strandings from 2019 and 2020 in Central Luzon Region. ............ 41
Figure 33. Monthly distribution of strandings from 2019 and 2020 in Central Luzon Region. ............. 41
Figure 34. Stranded marine mammal species from 2019 and 2020 in Central Luzon Region. ............. 42
Figure 35. Stranding event categories from 2019 to 2020 in Central Luzon Region. ............................ 42
Figure 36. Distribution of strandings from 2019 to 2020 in CALABARZON Region. .............................. 44

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Marine mammal strandings in the Philippines from 2019 to 2020
Figure 37. Number of strandings within 15 x 15 km from 2005 to 2020 in CALABARZON Region. ...... 45
Figure 38. Strandings per province from 2019 and 2020 in CALABARZON Region. .............................. 46
Figure 39. Monsoonal distribution of strandings from 2019 to 2020 in CALABARZON Region. ........... 46
Figure 40. Seasonal distribution of strandings from 2019 to 2020 in CALABARZON Region. ............... 47
Figure 41. Monthly distribution of strandings from 2019 to 2020 in CALABARZON Region. ................ 47
Figure 42. Stranded marine mammal species from 2019 to 2020 n CALABARZON Region. ................. 48
Figure 43. Stranding event categories from 2019 to 2020 in CALABARZON Region. ........................... 48
Figure 44. Distribution of strandings from 2019 to 2020 in MIMAROPA Region. ................................ 50
Figure 45. Number of strandings within 15 x 15 km from 2005 to 2020 in MIMAROPA Region. ......... 51
Figure 46. Strandings per province from 2019 to 2020 in MIMAROPA Region. ................................... 52
Figure 47. Monsoonal distribution of strandings from 2019 to 2020 in MIMAROPA Region. .............. 52
Figure 48. Seasonal distribution of strandings from 2019 to 2020 in MIMAROPA Region. .................. 53
Figure 49. Monthly distribution of strandings from 2019 and 2020 in MIMAROPA Region. ................ 53
Figure 50. Stranded marine mammal species from 2019 to 2020 in MIMAROPA Region. ................... 54
Figure 51. Stranding event categories from 2019 to 2020 in MIMAROPA Region. .............................. 54
Figure 52. Distribution of strandings from 2019 to 2020 in Bicol Region. ............................................ 56
Figure 53. Number of strandings within 15 x 15 km from 2005 to 2020 in Bicol Region. ..................... 57
Figure 54. Strandings per province from 2019 to 2020 in Bicol Region. ............................................... 58
Figure 55. Monsoonal distribution of strandings from 2019 to 2020 in Bicol Region. ......................... 58
Figure 56. Seasonal distribution of strandings from 2019 to 2020 in Bicol Region. ............................. 59
Figure 57. Monthly distribution of strandings from 2019 to 2020 in Bicol Region. .............................. 59
Figure 58. Stranded marine mammal species from 2019 to 2020 in Bicol Region. .............................. 60
Figure 59. Stranding event categories from 2019 to 2020 in Bicol Region. .......................................... 60
Figure 60. Distribution of strandings from 2019 and 2020 in Western Visayas Region. ...................... 62
Figure 61. Number of strandings within 15 x 15 km from 2005 to 2020 in Western Visayas Region... 63
Figure 62. Strandings per province from 2019 to 2020 in Western Visayas Region. ............................ 64
Figure 63. Monsoonal distribution of strandings from 2019 to 2020 in Western Visayas Region. ...... 64
Figure 64. Seasonal distribution of strandings from 2019 to 2020 in Western Visayas Region. .......... 65
Figure 65. Monthly distribution of strandings from 2019 to 2020 in Western Visayas Region. ........... 65
Figure 66. Stranded marine mammal species from 2019 to 2020 in Western Visayas Region. ........... 66
Figure 67. Stranding event categories from 2019 to 2020 in Western Visayas Region. ....................... 66
Figure 68. Distribution of strandings from 2019 to 2020 in Central Visayas Region. ........................... 68
Figure 69. Number of strandings within 15 x 15 km from 2005 to 2020 in Central Visayas Region. ... 69
Figure 70. Strandings per province from 2019 to 2020 in Central Visayas Region. .............................. 70
Figure 71. Monsoonal distribution of strandings from 2019 to 2020 in Central Visayas Region. ........ 70
Figure 72. Seasonal distribution of strandings from 2019 to 2020 in Central Visayas Region. ............ 71
Figure 73. Monthly distribution of strandings from 2019 to 2020 in Central Visayas Region. ............. 71
Figure 74. Stranded marine mammal species from 2019 to 2020 in Central Visayas Region. ............. 72
Figure 75. Stranding event categories from 2019 to 2020 in Central Visayas Region. ......................... 72
Figure 76. Distribution of strandings from 2019 to 2020 in Eastern Visayas Region. .......................... 74
Figure 77. Number of strandings within 15 x 15 km from 2005 to 2020 in Eastern Visayas Region. ... 75
Figure 78. Strandings per province from 2019 to 2020 in Eastern Visayas Region. ............................. 76
Figure 79. Monsoonal distribution of strandings from 2019 to 2020 in Eastern Visayas Region. ........ 76
Figure 80. Seasonal distribution of strandings from 2019 to 2020 in Eastern Visayas Region. ............ 77
Figure 81. Monthly distribution of strandings from 2019 to 2020 in Eastern Visayas Region. ............ 77
Figure 82. Stranded marine mammal species from 2019 to 2020 in Eastern Visayas Region. ............. 78
Figure 83. Stranding event categories from 2019 to 2020 in Eastern Visayas Region. ........................ 78
Figure 84. Distribution of strandings from 2019 to 2020 in Zamboanga Peninsula Region. ................ 80

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Marine mammal strandings in the Philippines from 2019 to 2020
Figure 85. Number of strandings within 15 x 15 km from 2005 to 2020 in Zamboanga Peninsula. .... 81
Figure 86. Strandings per province from 2019 to 2020 in Zamboanga Peninsula. ............................... 82
Figure 87. Monsoonal distribution of strandings from 2019 to 2020 in Zamboanga Peninsula. ......... 82
Figure 88. Seasonal distribution of strandings from 2019 to 2020 in Zamboanga Peninsula Region. . 83
Figure 89. Monthly distribution of strandings from 2019 to 2020 in Zamboanga Peninsula Region. .. 83
Figure 90. Stranded marine mammal species from 2019 to 2020 in Zamboanga Peninsula Region. .. 84
Figure 91. Stranding event categories from 2019 to 2020 in Zamboanga Peninsula Region. .............. 84
Figure 92. Distribution of strandings from 2019 to 2020 in Northern Mindanao. ................................ 86
Figure 93. Number of strandings within 15 x 15 km from 2005 to 2020 in Northern Mindanao. ........ 87
Figure 94. Strandings per province from 2019 to 2020 in Northern Mindanao. .................................. 88
Figure 95. Monsoonal distribution of strandings from 2019 to 2020 in Northern Mindanao Region. . 88
Figure 96. Seasonal distribution of strandings from 2019 to 2020 in Northern Mindanao Region. ..... 89
Figure 97. Monthly distribution of strandings from 2019 to 2020 in Northern Mindanao. ................. 89
Figure 98. Stranded marine mammal species from 2019 to 2020 in Northern Mindanao. .................. 90
Figure 99. Stranding event categories from 2019 to 2020 in Northern Mindanao. ............................. 90
Figure 100. Distribution of strandings from 2019 to 2020 in Davao Region. ....................................... 92
Figure 101. Number of strandings within 15 x 15 km from 2005 to 2020 in Davao Region. ................ 93
Figure 102. Strandings per province from 2019 to 2020 in Davao Region. .......................................... 94
Figure 103. Monsoonal distribution of strandings from 2019 to 2020 in Davao Region. ..................... 94
Figure 104. Seasonal distribution of strandings from 2019 to 2020 in Davao Region. ........................ 95
Figure 105. Monthly distribution of strandings from 2019 to 2020 in Davao Region. ......................... 95
Figure 106. Stranded marine mammal species from 2019 to 2020 in Davao Region. .......................... 96
Figure 107. Stranding event categories from 2019 to 2020 in Davao Region. ..................................... 96
Figure 108. Distribution of strandings from 2019 to 2020 in SOCCSKSARGEN Region. ........................ 98
Figure 109. Number of strandings within 15 x 15 km from 2005 to 2020 in SOCCSKSARGEN Region.. 99
Figure 110. Strandings per province from 2019 to 2020 in SOCCSKSARGEN Region. ......................... 100
Figure 111. Monsoonal distribution of strandings from 2019 to 2020 in SOCCSKSARGEN Region. ... 100
Figure 112. Seasonal distribution of strandings from 2019 to 2020 in SOCCSKSARGEN Region. ....... 101
Figure 113. Monthly distribution of strandings from 2019 to 2020 in SOCCSKSARGEN Region. ........ 101
Figure 114. Stranded marine mammal species from 2019 to 2020 in SOCCSKSARGEN Region. ........ 102
Figure 115. Stranding event categories from 2019 to 2020 in SOCCSKSARGEN Region. .................... 102
Figure 116. Distribution of strandings from 2019 to 2020 in Caraga Region. .................................... 104
Figure 117. Number of strandings within 15 x 15 km from 2005 to 2020 in Caraga Region. ............. 105
Figure 118. Strandings per province from 2019 to 2020 in Caraga Region. ....................................... 106
Figure 119. Monsoonal distribution of strandings from 2019 to 2020 in Caraga Region. ................. 106
Figure 120. Seasonal distribution of strandings from 2019 to 2020 in Caraga Region. ..................... 107
Figure 121. Monthly distribution of strandings from 2019 to 2020 in Caraga Region. ...................... 107
Figure 122. Stranded marine mammal species from 2019 to 2020 in Caraga Region. ...................... 108
Figure 123. Stranding event categories from 2019 to 2020 in Caraga Region. .................................. 108
Figure 124. Distribution of strandings from 2019 to 2020 in BARMM Region. .................................. 110
Figure 125. Number of strandings within 15 x 15 km from 2005 to 2020 in BARMM Region. ........... 111
Figure 126. Strandings per province from 2019 to 2020 in BARMM Region. .................................... 112
Figure 127. Monsoonal distribution of strandings from 2019 to 2020 in BARMM Region. ................ 112
Figure 128. Seasonal distribution of strandings from 2019 to 2020 in BARMM Region. ................... 113
Figure 129. Monthly distribution of strandings from 2019 to 2020 in BARMM Region. .................... 113
Figure 130. Stranded marine mammal species from 2019 to 2020 in BARMM Region...................... 114
Figure 131. Stranding event categories from 2019 to 2020 in BARMM Region. ................................ 114

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Marine mammal strandings in the Philippines from 2019 to 2020
LIST OF TABLES
Table 1. Total number of grids with stranding records in the Philippines. ........................................... 16
Table 2. Areas or grids with 9 to 12 and ≥13 recorded stranding events. ............................................ 16
Table 3. Stranding events per region from 2019 to 2020. .................................................................... 21

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Marine mammal strandings in the Philippines from 2019 to 2020
ACKNOWLEDGEMENTS
This report is a product of our continuing network effort and would not have been possible without
the support of the University of the Philippines – Diliman, particularly the Marine Mammal Research
& Stranding Laboratory of the Institute of Environmental Science & Meteorology, and the Philippine
Marine Mammal Stranding Network. Many thanks to UP Diliman officers, namely former Chancellor
Michael Tan and current Chancellor Fidel Nemenzo for their continuous support, and the College of
Science Dean Giovanni Tapang. Again, special appreciation to the teamwork and support from
PMMSN’s core member institutions: DA-BFAR, Ocean Adventure, all coastal LGUs and UP IESM. Special
mention to BFAR National Director, Retired Cmdr Eduardo Gongona for his never-ending support.
Also, the PMMSN is especially indebted to the BFAR Regional Directors for also acting as Board
Members of the PMMSN and heading their respective regional chapters: Rosario Segundina Gaerlan
(I), Angel Encarnacion (II), Wilfredo Cruz (III), Sammy Malvas (IV-A), Elizer Salilig (IV-B), Nelson Bien
(V), Remia Aparri (VI), Allan Poquita (VII), John Albaladejo (VIII), Isidro Velayo, Jr (IX), Teodore Bacolod,
Jr (X), Raul Millana (XI), Alfeo Piloton & Usop Pendaliday, Jr (XII), Visa Dimerin, Omnia Olama & Nilo
Katada (XIII), and DG Pendatun Patarasa (BARMM). Special mention to Belmor Bugaoan (BFAR 1),
Marjurie Grutas (BFAR V), Elen Ylanan (BFAR VII), and Ghie Bartolome (BFAR IV-A) for always being
there to serve the PMMSN in either active or retired duties. Similarly, we will always be grateful to
retired RDs Jovita Ayson, Esmeralda Manalang, Remedios Ontangco, Andy Bojos, Lilian Garcia,
Milagros Morales, Visa Dismerin, Janice Musali, and Alfeo Piloton. Thank you to the former BFAR
national directors: Malcolm Sarmiento and Asis Perez for their foresight in seeing the value of PMMSN.
This national stranding network is also grateful to the many LGU chief executives from Governors and
Mayors whom we have had the pleasure to work with in various stranding response activities. Special
mention to Governors Jose Riano (Romblon) and Steve Solon (Sarangani), and Mayors Richard Gomez
(Ormoc City), Art Celeste (Alaminos City) and Isabelle Climaco (Zamboanga City).
There are many people who have assisted in the collection of data and samples and submission of
reports and photos whom we are grateful for. Again, these are the passionate people who have given
so much time to their respective PMMSN Chapters. We thank Henry Canlas, Jeff Soriano, Nonie Enolva,
Art Valente, Johann Tejada, Ann Finalla, Glen Padro, Gefel Mamhot, Irish Belmonte, Joy Uriarte, Maia
Lim, Gary Cabinta, Rita Sarmiento, Richard Muallil, Wing Olama, Rey Ramilo, Bong Tuballes, Susan
Noche, Ramil del Rosario, Winston Plaza, Cornelio Ramirez, and our regular vets: Drs Hasmin
Chogsayan, Ronnie & Lilian Duque, Arnold Dela Cruz, Jeff Soriano, Henry Centeno, Elma Bermudez,
Marco Espiritu, Milcah Valente, Joy Seledio, Kris Gonzales, Leona Ortega, Pido Manglicmot, Froiland
Sanchez, Suzette Apura, Cristine Redona, Bernadeth Florentin, Rogelio Gocotano Jr, Aveguin Meguillo,
Ian Prado, JM Victoria, Jen Rivero, Mario Arriola, Enrique Espiritu, Roy Mejorada, Jen Rivero, Evelyn
Saberon, and Arnedo Agbayani.
The PMMSN has faced many challenges but continues to be the difference. Thanks to our hard-core
officers: Dr Leo Suarez, Dr Chris Torno, Dr Mariel Buccat-Flores, Bianca Espinos, and our other
supporters namely, Jerson Vitug, Jean Balquin, Jonah Paz, Drs Toni Guy, Mike Briggs, Em Lastica, Sandy
Ling Choo, Che Garcia, and Professor Emeritus Joseph Masangkay (our adviser). Also, our utmost
appreciation to our regular lab mates: Dr Christine Obusan & Dr Jonah Bondoc, and Kimberly
Benjamin, Jamaica Caras, Janine Bobadilla, Phro Cabrera, John Ordinario, Rizza Bugtong, Charina
Villania, Erina Molina, and Russell Corcino.
Again, there is a very long list of people to thank here, and we are sure we have forgotten some. We
apologize for any inadvertent omissions then.

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Marine mammal strandings in the Philippines from 2019 to 2020
EXECUTIVE SUMMARY
Stranding of marine mammals is complex and understanding this phenomenon requires continuous
surveillance, monitoring, data collection and research. The Philippine Marine Mammal Stranding
Network (PMMSN) has collected 1178 records of stranding events nationwide from 2005 to 2020. This
Technical Report is a follow-up to the second Report (i.e., Aragones and Laggui 2019). As stated in the
second Technical Report the consequent series of Reports will cover two-year periods only. Thus, this
third Report covers the stranding dataset from 2019 to 2020. However, as in the first (Aragones et al.
2017) and second Reports, updates on the general trends for the larger data set (2005 to 2020) will
also be provided.
This Report showcases analyses of the stranding records from 2019 to 2020 (n=220) for trends in
stranding frequency by year, region, season, monsoon, species, sex, age class, original disposition,
release and rehabilitation success. The spatial coverage presented in this report was specific to regions
and provinces primarily for administrative purposes. Identification of more specific or smaller spatial
areas (i.e., by municipality/city) for potential stranding hotspots was assessed using Fishnet Tools
(using 15 x 15 km grids). Furthermore, seasonality of stranding events was categorized according to
the prevailing monsoons. The Northeast (NE) monsoon months are November to February (NDJF),
Southwest (SW monsoon) monsoon months are June to September (JJAS), and Spring Inter-monsoon
(Spring IM) in October (or Lull before NE monsoon) and the Winter Inter-monsoon (Winter IM) from
March to May (MAM, or Lull before SW monsoon). The stranding data was also presented in the more
classic seasonal context of DJF, MAM, JJA, SON. As data analytics advances, future reports will be
improved further.
Strandings in the Philippines have generally increased through time. In a moving average of the annual
stranding frequencies from 2005 to 2020, the first five years (2005-2009) had an average of 34,
followed by the next five (2010-2014), 73, and the last 6 years (2015-2020) had 108. The annual
frequencies have apparently plateaued since 2014. The increasing trend and plateau imply that the
continuing high total annual frequencies is beyond the artifact of people being educated about
strandings and reporting them but that this sustained strandings must be compounded by other
factors. In 2010, the main factors that explained the increasing trends then were: increasing
awareness, toxins, and fishing efforts (both legal & illegal; Aragones at al. 2010). The PMMSN through
the Marine Mammal Research and Stranding Laboratory of the UP IESM is currently examining the
effects of pollution (chemical & noise), diseases, marine debris and by-catch on marine mammal
stranding events nationwide, to mention a few.
The previous Technical Report showed that there are distinct regional hotspots in each Island group
of Luzon, Visayas and Mindanao from 2005 to 2018 dataset. Strandings in the last 2 years (2019-2020)
highlighted these top five regions: Region I (Ilocos Region, n=26), Region V (Bicol Region, n=26), Region
VI (Western Visayas, n=25), Region IV-B (MIMAROPA, n=22) and Region VII (Central Visayas, n=23).
There were 3 regions (I, IV-B, V) in the top five from the previous Technical Report. All these three
regions are in Luzon. These five (5) hotspots regions accounted for 55.45% of the total stranding
events from 2019 to 2020.
Grids of 15 x 15 km were employed via Fishnet Tool in this latest Report to visualize the specific areas
where stranding events frequently occurred. Almost a third (440 of 1368, 32.16%) of the grids created
along the Philippine coastline had records of stranding events from 2005 to 2020. Eighteen (18)

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Marine mammal strandings in the Philippines from 2019 to 2020
hotspots (areas of concern, total stranding frequency ≥9 per grid) on a municipal/city level were
identified: Sta Ana (n=19), Badoc (n=18), Dagupan (n=16), Pagudpud (n=15), Alaminos City (n=14),
Claveria (n=13), Davao City (n=13), Labrador (n=12), Mati (n=12), Del Gallego (n=11), Bago City (n=11),
Malapatan (n=11), Pasuquin (n=10), Maco (n=10), Sto Domingo (n=9), Narvacan (n=9), Davao City
(n=9), and Zamboanga City (n=9). Ilocos remains the primary region of concern since it hosts 8
stranding hotspot municipalities/cities. Region II, Region V, Region VI, Region IX, Region XI, and Region
XII are approaching the rates to be considered areas of concern as well.
To date, roughly a third of the coastline of the Philippine archipelago has had stranding records. The
Fishnet Tool identified municipal/city level areas of concern. These specific areas should be the
primary or focal areas of interest for the concerned Provincial Fisheries Officers and BFAR Regional
Directors in terms of strategic management or planning for training requests and the like. The top
seven (7) provinces with the highest frequency of recorded strandings were Palawan (n=10), Negros
Occidental (n=10), Ilocos Norte (n=9), Ilocos Sur (n=9), Cagayan (n=9), Cebu (n=9), and Sarangani (n=9).
There were no clear patterns nor trends for the monsoonal distribution of strandings in 2019 to 2020.
The total frequency during the Northeast monsoon (n=90) was closely followed by the Southwest
monsoon (n=69), then Winter Inter-monsoon (Lull before SW; n=47), and Spring Inter-monsoon (Lull
before NE; n=14). In terms of seasonality, 36% of the total strandings occurred during MAM season
(n=80), 25% during JJA season (n=55), 20% during DJF season (n=44), and 18.64% during SON season
(n=41). Majority of these strandings in 2019 to 2020 involved single stranding events (n=214). There
were only five (5) records of mass strandings and one out of habitat.
The 5 most frequent species to strand in recent years (2019-2020) were again the were spinner
dolphin (n=35), followed by pygmy sperm whale (n=23), Fraser’s dolphin (n=22), dugong (n=18),
melon-headed whale (n=17), Risso’s dolphin (n=12), and short-finned pilot whale (n=12). The number
of stranding records per species is most alarming for the dugong (Dugong dugon) as it is a critically
endangered species in the Philippines. Based on the previous Technical Report, the dugong had a total
of 62 stranding records for 14 years (from 2005 to 2018) nationwide. That is equivalent to an average
of 4 strandings per year, one stranding increase from the previous average (2005-2016) – a trend that
is consistently observed to date. In 2019 & 2020, the dugong had a total of 18 stranding records. This
increased the annual average of dugong strandings since 2005 to 5 strandings per year. Majority of
these dugong mortalities came from the provinces of Palawan (n=3), Guimaras (n=2), Sarangani (n=2),
and Surigao del Sur (n=2).
Overall, there were only 37.27% (n=82) live marine mammals in 2019 and 2020 out of all stranding
events (Figure 4). Of the live stranders, 29 (~36%) eventually died, 24 (~29%) released and 16 (~20%)
animals were rehabilitated. Of the 24 released, 5 animals reportedly died. Out of the 16 marine
mammals rehabilitated or given at least 24-hour supportive care, 7 survived and were released
successfully (~44%). Thirteen (13) of the 82 live stranders were undetermined. Again, these trends and
patterns of strandings, and releases and rehabilitations would not have been possible if not for the
efforts of the PMMSN.

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Marine mammal strandings in the Philippines from 2019 to 2020
INTRODUCTION
A robust stranding database is key to understanding marine mammal strandings as well as long-term
environmental changes. Data collection and archiving of samples from stranded marine mammals
provide insights on numerous rare and even endangered species. These datasets can account for
marine mammal species composition, distribution, movement patterns, proxies to their population
sizes (Norman et al. 2004, Pyenson 2011) and ocean and human health (Moore 2008, Bossart 2011).
Furthermore, beached specimens can yield valuable records on anatomy, life history, genetics,
disease, parasites, contaminants and feeding ecology that are otherwise hard to obtain when studying
marine mammals in the wild (Perrin and Geraci 2002, Vianna et al. 2016).
The data and samples collected from stranded marine mammals in the country presented many
opportunities for studying several aspects of these rarely studied animals. For example, in 2015, a
comprehensive study on microbiology of stranded cetaceans was investigated by Obusan et al.,
detecting potentially pathogenic microbes. Likewise, stranding events from 2012 to 2013 and 2017 to
2018 provided information on the antibiotic resistance of pathogenic microorganisms from select
stranded cetaceans (Obusan et al. 2018, Obusan et al. 2021). Obusan et al. 2019 also utilized stranding
occurrences from October 2016 to August 2018 and detected the likelihood of toxoplasmosis and
leptospirosis in cetaceans. Similarly, De Guzman et al. 2020 examined toxoplasmosis molecularly from
select samples from 2019. Studies examining the microbiology of marine mammals’ aid in determining
plausible pathogenic infections and antimicrobial resistance among and within populations. Similarly,
a study by Bondoc et al. (2017) attempted to examine the causes of stranded marine mammals in the
country using histopathological and hematological techniques. In the case of impacts of human
interaction on marine mammal stranding, evidence was provided by the study of Obusan et al. 2016.
An acoustic trauma from blast fishing related study on stranded marine mammals was also
investigated (Paccini et al. 2016) as well as the transmission beam pattern of a spinner dolphin (Smith
et al. 2019). Blood values for the data deficient spinner dolphins have been established from
rehabilitated stranders (Suarez et al. 2019). Polychlorinated biphenyls (PCBs) contamination was
analyzed in a stranded dwarf sperm whale in Camarines Sur and rough-toothed dolphin in Zambales
(Bondoc et al. 2021). Moreover, the comprehensive stranding database of the country has been
utilized to elucidate the ecology of these animals (Aragones et al. unpublished data). An initial analysis
was conducted by Aragones et al. 2010 using the compiled stranding data from 1998 to 2009
examining spatial and temporal trends as well as identifying potential geographical hotspots. More
comprehensive analyses of the national stranding database from 2005 to 2016 was conducted by
Aragones and his colleagues in 2017. The first Technical Report served as the primary assessment of
the long-term (12 years) marine mammal stranding dataset collected since 2005. The second Technical
Report initiated the biennial analysis to ensure early identification of issues related to stranded marine
mammals nationwide.
This third Technical Report aims to continue what the second report did. That is to highlight the results
of the ongoing investigation of the various aspects of marine mammal strandings in the Philippines.
Specifically, the purpose of this report are to (1) map stranding events per region, and identify
stranding hotspots on a localized level (i.e. municipal-provincial) using the previous (2005 to 2020)
and recent (2019 to 2020) dataset; and (2) examine trends of recent stranding data (2019 to 2020)
regarding (i) species composition, (ii) spatial (by regions) and temporal variation or patterns (iii)
proportions of sex, live and dead stranders, refloated/released and rehabilitated stranded marine
mammals in the country and on a regional basis.

12
Marine mammal strandings in the Philippines from 2019 to 2020
These Technical Reports offer valuable information since data on marine mammals in the Philippines
is limited. This information is fundamental for the protection and conservation of marine mammals in
the Philippines. Also, these reports identify marine mammal hotspot areas relevant to the
municipal/city, provincial and regional levels. The systematic collection and collation of stranding data
in the country have been providing information on One Health: marine mammals, environment, and
humans. The Memorandum of Agreements between PMMSN and the various Regional BFAR offices,
authorizing PMMSN to conduct its five core activities: rescue, release or refloat, rehabilitate,
repository of samples and research remain vital. Another key instrument is an active MOU between
PMMSN and the Marine Mammal Research and Stranding Laboratory of the Institute of Environmental
Science & Meteorology of the University of the Philippines – Diliman to act as its research arm. The
strength of this national network is its empowered chapters and focus on science.
METHODS
The primary methods regarding the collection and collation of the stranding data followed the first
Technical Report in 2017 (Aragones et al. 2017). As in previous Technical Reports, the overall dataset
is updated in this report, which now covers the period from 2005 to 2020, focusing on biennial years
of 2019 to 2020. These recent stranding records were analyzed for trends in stranding frequency by
year, region, season, species, gender, age class, disposition, and rehabilitation success rate. The spatial
coverage presented in this report were specific to regions and provinces as these are important for
administrative purposes. The more specific or smaller spatial examination (i.e., by municipality/city)
is described below. Furthermore, months were categorized according to the prevailing monsoons
(after Wang and Ho 2002, Wang 2006, Villafuerte et al. 2014). The Northeast (NE) monsoon months
are November to February (NDJF), Southwest (SW monsoon) monsoon months are June to September
(JJAS), and Spring Inter-monsoon (Spring IM) in October (or Lull before NE monsoon) and the Winter
Inter-monsoon (Winter IM) from March to May (MAM, or Lull before SW monsoon). The stranding
data was also presented in the more classic seasonal context of DJF, MAM, JJA, SON.
Collected stranding data on locations (i.e., sitio, barangay, municipality/city) were converted to
corresponding latitude and longitude. Stranding data was imported into ArcMap 10.1 and re-projected
into a UTM coordinate system (WGS 1984 Zone 51 N) for visual inspection of the distribution. Fishnet
Tool map was used to identify hotspot areas in a municipal/city level (Figure 1). A 15 x 15 km grid was
created using the Fishnet Tool of ArcMap 10.1. The 15 x 15 km grid size was used based on the
assumption that this size represents the extent or coverage of most municipalities or cities coastline.
Stranding data points were then joined into the Fishnet output which served as the target feature
using one to one join operation. The total number of stranding points that fall within each 15 x 15 km
grid was calculated and was again classified based on the natural break method.

13
Marine mammal strandings in the Philippines from 2019 to 2020
RESULTS
GENERAL TRENDS OF STRANDING EVENTS IN THE PHILIPPINES
A total of 1178 marine mammal stranding events have been recorded in the Philippines from 2005 to
2020, with a total of 220 strandings from 2019 to 2020 comprising 18.68% of the total stranding
events. In a moving average of the annual stranding frequencies from 2005 to 2020, the first five years
(2005-2009) was 34, followed by the next five (2010-2014), 73, and the last six years (2015-2020) was
108.
Out of the 1368 grids (15 x 15km) created along the Philippine coastline (Figure 1) using the Fishnet
Tool, 32.16% (n=440) had incidences of stranding from 2005 to 2020. The frequency of stranding
occurrences is summarized in Table 1. Areas where there were greater than or equal to 9 stranding
events were considered hotspots (areas of concern) on a municipal level (Table 2). Eleven (11)
municipalities had 9 to 12 stranding occurrences including 4 municipalities from Region I (Narvacan,
Sto Domingo, Pasuquin, Labrador), Region V (Camarines Sur), Region VI (Bago City), Region IX
(Zamboanga City), Region XI (Davao City, Maco, Mati), and Region XII (Malapatan). Meanwhile, 7
municipalities (Davao City, Claveria, Sta Ana, Alaminos City, Pagudpud, Dagupan, Badoc) covering
Region XI, Region II, and Region I had greater than or equal to 13 stranding events documented,
respectively.
In 2019 and 2020, the top five regions with the highest stranding occurrences as shown in Table 3
were Region I (Ilocos Region, n=26), Region V (Bicol Region, n=26), Region VI (Western Visayas, n=25),
Region VII (Central Visayas, n=23) and Region IV-B (MIMAROPA, n=22). Strandings recorded in these
5 areas practically contributed 55.45% of the total stranding events in the period covered. Region V
now ranks among the regions with the highest stranding individuals recorded for the past 2 years. On
the other hand, the regions with the lowest stranding incidences were BARMM (n=4), Region X
(Northern Mindanao, n=5), Region IX (Zamboanga Peninsula, n=8) and Region IV-A (CALABARZON,
n=8). BARMM remained the region with the least number of reported standing cases among regions.
The provinces with high total stranding incidences in 2019 to 2020 were Palawan (n=10), Negros
Occidental (n=10), Ilocos Norte (n=9), Ilocos Sur (n=9), Cebu (n=9), Sarangani (n=9), Pangasinan (n=7),
Bataan (n=7), Occidental Mindoro (n=7), Camarines Sur (n=7) and Negros Oriental (n=7). Of these 11
provinces, 2 had the highest stranding frequency documented in 2020 namely Ilocos Sur and
Pangasinan, as shown in Figure 9. Cebu, Palawan, Ilocos Norte, and Negros Occidental had stranding
frequency at the maximum in 2019 (Figure 9).
In terms of stranding frequency by monsoon in 2019 to 2020, more strandings occurred during the
Northeast monsoon (n=90), followed closely by Southwest monsoon (n=69), then Winter Inter-
monsoon (Lull before SW; n=47), and Spring Inter-monsoon (Lull before NE; n=14). The spread of the
recorded stranding events in the country per season for each region is shown in Figure 10. A glaring
trend from the 2019 to 2020 dataset were that more strandings were recorded during the Northeast
monsoon in Regions I, V, VI, and VII.
By season, from 2019 to 2020, 36% of the total strandings occurred during MAM season (n=80), 25%
during JJA season (n=55), 20% during DJF season (n=44), and 18.64% during SON season (n=41). The
stranding frequency by season by region from 2019 to 2020 is shown in Figure 11. The highest trends
per region occurred during the MAM season in Regions I and XII, and during the SON season in Region
X.

14
Marine mammal strandings in the Philippines from 2019 to 2020
Analysis of the data per year shows that the highest stranding events in the country were recorded in
years 2017 (n=121), 2019 (n=119), and 2015 (n=113; Figure 2), with single stranding events occurring
mostly in 2019 and 2020 (n=220). In 2019 to 2020, there were only five records of mass strandings
and one out of habitat (Figure 3).
Overall, there were only 37.27% (n=82) live marine mammals in 2019 and 2020 out of all stranding
events (Figure 4). This rate is low in comparison to years 2017-2018 (56.33%). Of the live stranders, 29
(~36%) died, 24 (~30%) released and 16 (~20%) animals were rehabilitated. Of the 24 released
stranders, 5 animals reportedly died. Out of the 16 marine mammals rehabilitated or given a few hours
of supportive care, 7 survived and were released successfully (~44%). Furthermore, for the past 2
years, 73.63% of the documented stranding event were adult (n=162), 16.82% were subadult (n=37),
and 7.27% were calf (n=16). Adult, subadult, and calf marine mammals stranded more frequently in
2019 than in 2020 (n=83, n=23, and n=10, respectively).
Majority of the stranded cetaceans’ sex was undetermined (36.36%, n=80; Figure 6). Only 34.55%
(n=76) and 26.26% (n=58) were identified as male and female, respectively. Additionally, the sex ratio
of stranded male to female from 2019 to 2020 was approximately even with a relative value of 1. In
terms of trends, more males were recorded to strand in 2019 (n=45) while females were relatively
higher in 2020 (n=36).
For the species composition of stranded marine mammals recorded in 2019 to 2020, 22 cetaceans and
1 sirenian were documented. In 2017-2018, 23 cetaceans and 1 sirenian were reported. The 5 most
frequent species to strand in recent years were spinner dolphin (Stenella longirostris, n=35), pygmy
sperm whale (Kogia breviceps, n=23), Fraser’s dolphin (Lagenodelphis hosei, n=22), dugong (Dugong
dugon, n=18), melon-headed whale (Peponocephala electra, n=17), Risso’s dolphin (Grampus griseus,
n=12), and short-finned pilot whale (Globicephala macrorhynchus, n=12; Figure 7).

15
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 1. NUMBER OF STRANDINGS WITHIN EACH 15 X 15 KM GRID USING 2005-2020 DATASET.

16
Marine mammal strandings in the Philippines from 2019 to 2020
TABLE 1. TOTAL NUMBER OF GRIDS WITH STRANDING RECORDS IN THE PHILIPPINES.
Count
Total grid along Philippine coast
1368
Grid with stranding points
440
Grid with 1-4 stranding points
367
Grid with 5-8 stranding points
55
Grid with 9-12 stranding points
11
Grid with ≥13 stranding points
7
TABLE 2. AREAS OR GRIDS WITH 9 TO 12 AND ≥13 RECORDED STRANDING EVENTS.
Municipality/City
Province
Region
Stranding
Count
Sta Ana
Cagayan
II
19
Badoc
Ilocos Norte
I
18
Dagupan
Pangasinan
I
16
Pagudpud
Ilocos Norte
I
15
Alaminos City
Pangasinan
I
14
Claveria
Cagayan
II
13
Davao City
Davao del Sur
XI
13
Labrador
Pangasinan
I
12
Mati
Davao Oriental
XI
12
Del Gallego
Camarines Sur
V
11
Bago City
Negros Occidental
VI
11
Malapatan
Sarangani
XII
11
Pasuquin
Ilocos Norte
I
10
Maco
Compostela Valley
XI
10
Sto Domingo
Ilocos Sur
I
9
Narvacan
Ilocos Sur
I
9
Davao City
Davao del Sur
XI
9
Zamboanga City
Zamboanga del Sur
IX
9

17
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 2. STRANDING EVENTS RECORDED FROM 2005 TO 2020.
FIGURE 3. CATEGORIES OF STRANDINGS IN YEAR 2019 TO 2020.
23
37
28 30
50 56
82
53
67
105 113
82
121
111 119
101
0
20
40
60
80
100
120
140
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
Stranding frequency
Year
118
1
96
41
0
20
40
60
80
100
120
140
Single Mass Out of habitat
Stranding frequency
Year
2019
2020

18
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 4. DISPOSITION OF STRANDED MARINE MAMMALS FROM 2019 TO 2020.
FIGURE 5. AGE CLASS OF STRANDED MARINE MAMMALS FROM 2019 TO 2020.
39
80
43
57
1
0
10
20
30
40
50
60
70
80
90
Alive Dead Mixed
Stranding frequency
Disposition
2019
2020
83
23
10
12
79
14
61 1
0
10
20
30
40
50
60
70
80
90
Adult Subadult Calf Mixed Mother & calf
Stranding frequency
Age class
2019
2020

19
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 6. SEX OF STRANDED MARINE MAMMALS FROM 2019 TO 2020.
45
22
3
49
31
36
3
31
0
10
20
30
40
50
60
Male Female Mixed Unknown
Stranding frequency
Age class
2019
2020

20
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 7. STRANDED MARINE MAMMAL SPECIES FROM 2019 TO 2020.
1
1
10
1
1
2
4
13
3
7
2
3
4
5
4
12
7
10
11
2
1
2
2
2
2
2
2
3
3
4
4
4
4
4
6
7
7
10
11
13
24
0 5 10 15 20 25 30
Unidentified balaenopterid
Omura's whale
Fin whale
Irrawaddy dolphin
Short-finned pilot whale
Pygmy killer whale
False killer whale
Bryde's whale
Blainville's beaked whale
Rough-toothed dolphin
Striped dolphin
Melon-headed whale
Sperm whale
Indo-Pacific bottlenose dolphin
Common bottlenose dolphin
Cuvier's beaked whale
Pantropical spotted dophin
Risso's dolphin
Dwarf sperm whale
Fraser's dolphin
Dugong
Pygmy sperm whale
Spinner dolphin
Stranding frequency
Marine mammal species
2019
2020

21
Marine mammal strandings in the Philippines from 2019 to 2020
TABLE 3. STRANDING EVENTS PER REGION FROM 2019 TO 2020.
Region
2019 (no. of
individuals)
2020 (no. of
individuals)
Total (no. of
individuals)
I (Ilocos Region)
13(14)
13(14)
26(28)
II (Cagayan Valley)
6
5
11
III (Central Luzon)
4
7
11
IV-A (CALABARZON)
3
5
8
IV-B (MIMAROPA)
14
8(9)
22(23)
V (Bicol Region)
13
13(22)
26(35)
VI (Western Visayas)
13(15)
12(13)
25(28)
VII (Central Visayas)
13
10
23
VIII (Western Visayas)
9
7
16
IX (Zamboanga Peninsula)
3
5
8
X (Northern Mindanao)
4
1
5
XI (Davao Region)
11
1
12
XII (SOCCSKSARGEN)
7
5
12
XIII (Caraga)
4
7
11
BARMM
2
2
4
Total
119(122)
101(113)
220(235)
FIGURE 8. STRANDING FREQUENCY PER REGION FROM 2019 TO 2020.
13
6
4
3
14
13 13 13
9
3
4
11
7
4
2
13
5
7
5
8
13
12
10
7
5
1 1
5
7
2
0
2
4
6
8
10
12
14
16
Stranding frequency
Region
2019
2020

22
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 9. STRANDING FREQUENCY PER PROVINCE FROM 2019 TO 2020.
0
1
2
3
4
5
6
7
8
9
Ilocos Norte
Ilocos Sur
La Union
Pangasinan
Batanes
Cagayan
Aurora
Bataan
Zambales
Batangas
Quezon
Marinduque
Occidental Mindoro
Palawan
Romblon
Albay
Camarines Norte
Camarines Sur
Catanduanes
Masbate
Sorsogon
Aklan
Antique
Capiz
Guimaras
Iloilo
Negros Occidental
Bohol
Cebu
Negros Oriental
Siquijor
Biliran
Leyte
Northern Samar
Samar
Southern Leyte
Zamboanga del Norte
Zambuanga Sibugay
Zamboanga del Sur
Camiguin
Lanao del Norte
Misamis Oriental
Compostella Valley
Davao del Norte
Davao del Sur
Davao Oriental
Davao Occidental
Sarangani
South Cotabato
Agusan del Norte
Siargao
Surigao del Norte
Surigao del Sur
Basilan
Maguindanao
Sulu
Tawi-Tawi
1 2 3 4A 4B 5 6 7 8 9 10 11 12 13 BARMM
Stranding frequency
Province
2019
2020

23
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 10. STRANDING FREQUENCY BY MONSOON BY REGION FROM 2019 TO 2020.
11
4
2
4
5
13
12
10
5
4
2
6
5
6
1
9
6
2
7
3
4
7
4
11111
0
2
4
6
8
10
12
14
1234A 4B 5678910 11 12 13 BARMM
Stranding frequency
Region
NE
Lull before SW
SW
Lull before NE

24
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 11. STRANDING FREQUENCY BY SEASON BY REGION FROM 2019 TO 2020.
3
2
1
3
2
7 7
5
2
1
2
4 4
1
6
5
2 2
8
3
5
4 4
3
2
5
4
2
14
2
6
2
8
6
8
12
7
3
2
3
5
2
1
3
2 2
1
4
10
5
2
3
1 1
3
2
1
0
2
4
6
8
10
12
14
16
1234A 4B 5 6 7 8 9 10 11 12 13 BARMM
Stranding frequency
Region
DJF JJA MAM SON

25
Marine mammal strandings in the Philippines from 2019 to 2020
Stranding per region
REGION I (ILOCOS REGION)
Ilocos Region was the hottest hotspot region tied with Region V for 2019 to 2020 (both n=26). The
distribution of the recorded stranding events within the region is shown in Figure 12. There were 13
recorded stranding events each in 2019 and 2020 (Figure 14). At the provincial level, Ilocos Norte and
Ilocos Sur (n=9) contributed the most in terms of the overall number of stranded marine mammals in
the region. Stranding frequency in Ilocos Norte was high in 2019 while stranding events in Ilocos Sur
and Pangasinan were higher in 2020 than in 2019. Only one stranding event occurred in La Union in
2019 and none in 2020.
Region 1 has the most numerous hotspot municipalities/cities nationwide. The concentration of
stranding events per municipality based on the 15 x 15 km grid is shown in Figure 13. As mentioned
above, the dataset used in this experiment covers the 2005 to 2020 recorded stranding events. A total
of 39 grids along the coastline of Ilocos Region had stranding occurrences. There were 20 grids that
involved 1 to 4 stranding events, 11 grids with 5 to 8, 4 grids 9 to 12 and 4 grids with more than 13
strandings, respectively. The grids with 9 to 12 stranding incidences were in Ilocos Norte (Pasuquin),
Ilocos Sur (Narvacan, Sto Domingo), and Pangasinan (Labrador), while grids with greater than 13
incidences were in Pagudpud, Ilocos Norte (n=15), Dagupan, Pangasinan (n=16), and Badoc, Ilocos
Norte (n=18).
The general trend was that most strandings occurred during the Northeast monsoon (n=11), followed
by during the Winter Inter-monsoon (n=9), and Southwest monsoon (n=6). There was no stranding
event during the lull before NE. Strandings during the Northeast monsoon peaked in Pangasinan in
2020 (n=5). Furthermore, strandings were consistently observed across monsoons and inter-monsoon
seasons in Ilocos Norte and Ilocos Sur (Figure 15).
By seasonality (Figure 16), approximately half (n=14) of the stranding events in the region were
documented during the March-April-May (MAM) season. There were 6 incidents during the JJA season
and 3 incidents each during the DJF and SON seasons. The maximum occurrences in Ilocos Sur
occurred during the MAM season (n=5), Moreover, Ilocos Norte and Ilocos Sur consistently had
stranding events in most seasons (Figure 16). In terms of month, stranding occurrences in the Ilocos
region from 2019 to 2020 had been observed to peak in March (2020, n=5) and May (2019, n=3; 2020,
n=2; Figure 17).
There were 14 marine mammal species recorded in this region as shown in Figure 18. The pygmy
sperm whale (Kogia breviceps) recorded the most stranding frequency (n=5). It was followed by
pantropical spotted dolphin (Stenella attenuata), Fraser’s dolphin (Lagenodelphis hosei), dwarf sperm
whale (Kogia sima), and spinner dolphin (Stenella longirostris) with a total of 3 stranding frequency
for each species. The stranding events documented a total of 28 individuals. There were 25 single and
1 mass stranding events. The mass stranding event occurred in 2020 which involved a male and a
female dwarf sperm whale adult (Kogia sima; Figure 19).

26
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 12. DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN ILOCOS REGION.

27
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 13. NUMBER OF STRANDINGS WITHIN 15 X 15 KM FROM 2005 TO 2020 IN ILOCOS REGION.

28
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 14. STRANDINGS PER PROVINCE FROM 2019 AND 2020 IN ILOCOS REGION.
FIGURE 15. MONSOONAL DISTRIBUTION OF STRANDINGS FROM 2019 AND 2020 IN ILOCOS REGION.
6
4
1
2
3
5 5
0
1
2
3
4
5
6
7
Ilocos Norte Ilocos Sur La Union Pangasinan
Stranding frequency
Province
2019
2020
2
1 1
2
5
2 2
1
2
1 1
2 2
1 1
0
1
2
3
4
5
6
2019 2020 2019 2020 2019 2020 2019 2020
Ilocos Norte Ilocos Sur La Union Pangasinan
Stranding frequency
Province
NE
Lull before SW
SW
Lull before NE

29
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 16. SEASONAL DISTRIBUTION OF STRANDINGS FROM 2019 AND 2020 IN ILOCOS REGION.
FIGURE 17. MONTHLY DISTRIBUTION OF STRANDINGS FROM 2019 AND 2020 IN ILOCOS REGION.
2
1
2 2
1 1
2 2
1
4
1 1
3
1
2
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
2019 2020 2019 2020 2019 2020 2019 2020
Ilocos Norte Ilocos Sur La Union Pangasinan
Stranding frequency
Province
DJF
JJA
MAM
SON
2 2
3
1
4
1
5
2 2
1
2
1
0
1
2
3
4
5
6
Stranding frequency
Month
2019
2020

30
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 18. STRANDED MARINE MAMMAL SPECIES FROM 2019 AND 2020 IN ILOCOS REGION.
FIGURE 19. STRANDING EVENT CATEGORIES FROM 2019 AND 2020 IN ILOCOS REGION.
1
3
1
1
2
1
1
1
1
1
2
2
2
1
2
1
1
1
1
0 1 2 3 4
Pantropical spotted dolphin
Pygmy sperm whale
Fraser's dolphin
Sperm whale
Dwarf sperm whale
Cuvier's beaked whale
Spinner dolphin
Rough-toothed dolphin
Blainville's beaked whale
Short-finned pilot whale
Risso's dolphin
Striped dolphin
Melon-headed whale
Common bottlenose dolphin
Stranding frequency
Species
2019
2020
6
2
4
5
1
2
5
1
0
1
2
3
4
5
6
7
2019 2020 2019 2020 2019 2020 2019 2020
Ilocos Norte Ilocos Sur La Union Pangasinan
Stranding frequency
Province
Single
Mass

31
Marine mammal strandings in the Philippines from 2019 to 2020
REGION II (CAGAYAN VALLEY)
The Cagayan Valley Region had the 7th highest number of stranding occurrences from 2019 to 2020
nationwide tied with Central Luzon and Caraga Region (n=11, see Table 3). The distribution of the
recorded stranding incidences is shown in Figure 20. A total of 11 stranding events were documented
for the past two years in Region 2. Five (5) incidences were observed during the year of 2020 while 6
were recorded in 2019. Nine (9) of the 11 stranding events occurred in the province of Cagayan. The
other two stranding events recorded were in Batanes, one of each in 2019 and 2020. Stranding cases
in Cagayan province were one stranding event higher in the year 2019 (n=5) than in 2020 (n=4; Figure
22).
Areas in Region II where stranding of marine mammals clustered are shown in Figure 21. A total of 17
(15 x 15 km) grids contained stranding data points recorded from 2005 to 2020. Of the 17 grids with
stranding data, 2 grids had greater than or equal to 13 incidences. The two grids were located along
the coasts of Claveria and Sta Ana, Cagayan. The remaining grids consisted of the 12 grids and 3 grids
which had 1 to 4 strandings and 5 to 8 stranding records, respectively.
In terms of monsoonal period, strandings in the region mostly occurred during the Southwest
monsoon (n=6). There were 4 stranding events during the Northeast monsoon and one during the lull
before NE monsoon. Majority of the strandings during the Southwest monsoon occurred in the
Cagayan province (n=4) and two from Batanes. The only stranding during the inter-monsoon occurred
in Cagayan in 2019 (Figure 23).
Stranding events were highest during the JJA season (n=5), while the rest of the seasons each had 2
strandings in the region in the past 2 years. The Cagayan province steadily had recorded stranding in
all seasons of both years. All strandings that occurred in Batanes were documented only during the
JJA season (Figure 24). The months of March, June, and August had the highest number of recorded
stranding events (n=2) in the region as shown in Figure 25.
A total of 8 marine mammal species have been recorded to strand in Region II (Figure 26). The Fraser’s
dolphin (Lagenodelphis hosei, n=4) was the most frequent species to strand. Additionally, all these
recorded stranding incidences were categorized as single events (Figure 27).

32
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 20. DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN CAGAYAN VALLEY REGION.

33
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 21. NUMBER OF STRANDINGS WITHIN 15 X 15 KM FROM 2005 TO 2020 IN CAGAYAN VALLEY REGION.

34
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 22. STRANDINGS PER PROVINCE FROM 2019 AND 2020 CAGAYAN VALLEY REGION.
FIGURE 23. MONSOONAL DISTRIBUTION OF STRANDINGS FROM 2019 AND 2020 IN CAGAYAN VALLEY REGION.
1
5
1
4
0
1
2
3
4
5
6
Batanes Cagayan
Stranding frequency
Province
2019
2020
3
11 1 1
3
1
0
0.5
1
1.5
2
2.5
3
3.5
2019 2020 2019 2020
Batanes Cagayan
Stranding frequency
Province
NE
Lull before SW
SW
Lull before NE

35
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 24. SEASONAL DISTRIBUTION OF STRANDINGS FROM 2019 AND 2020 IN CAGAYAN VALLEY REGION.
FIGURE 25. MONTHLY DISTRIBUTION OF STRANDINGS FROM 2019 AND 2020 IN CAGAYAN VALLEY REGION.
1 11 1 1
2
0
0.5
1
1.5
2
2.5
2019 2020 2019 2020
Batanes Cagayan
Stranding frequency
Province
DJF
JJA
MAM
SON
2 2
1 11
2
1 1
0
0.5
1
1.5
2
2.5
Stranding frequency
Month
2019
2020

36
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 26. STRANDED MARINE MAMMAL SPECIES FROM 2019 AND 2020 IN CAGAYAN VALLEY REGION.
FIGURE 27. STRANDING EVENT CATEGORIES FROM 2019 TO 2020 IN CAGAYAN VALLEY REGION.
3
1
1
1
1
1
1
1
1
01234
Fraser's dolphin
Short-finned pilot whale
Pygmy sperm whale
Bryde's whale
Rough-toothed dolphin
Pantropical spotted dophin
Risso's dolphin
Spinner dolphin
Stranding frequency
Species
2019
2020
1 1
5
4
0
1
2
3
4
5
6
2019 2020 2019 2020
Batanes Cagayan
Stranding frequency
Province
Single

37
Marine mammal strandings in the Philippines from 2019 to 2020
REGION III (CENTRAL LUZON)
The Central Luzon Region recorded a total of 11 stranding occurrences from 2019 and 2020 tied with
Cagayan Valley and Caraga as the regions with 7th highest stranding occurrences nationwide from 2019
to 2020 (see Table 3). There were 4 and 7 stranding events recorded in 2019 and 2020, respectively.
The spread of these events is shown in Figure 28. Relative to the other provinces of the region, Bataan
(n=7) had the highest stranding frequency documented (Figure 30). Of the 7 stranding cases in the
area, 4 occurred in 2020 and the 3 were recorded in 2019. The province of Zambales and Aurora had
3 and 1 stranding events recorded that have occurred in 2020 and 2019, respectively.
The clusters of marine mammal stranding areas from 2005 to 2020 in Region III is shown in Figure 29.
A total of 23 grids had stranding incidences recorded. Seventeen (17) of the 23 grids had 1 to 4
stranding cases and the remaining had 5 to 8 cases. The municipality of Morong, Bataan recorded the
highest number of stranding frequencies for the entire region (n=7).
Stranding events in Central Luzon occurred most frequently during the Winter Inter-monsoon season
(n=6; Figure 31). Most of the stranding events in this season were recorded in Zambales in 2020.
Bataan had both 2 stranding events during the Northeast monsoon in 2019 and Southwest monsoon
in 2020.
In terms of seasonality, the MAM season had the most strandings with a total of 6 events distributed
across the provinces of Region III. It was notable that most seasons in Bataan had at least one stranding
event in both years. Meanwhile, Aurora and Zambales only had strandings during the MAM season
(Figure 32).
Six (6) of the 12 months had reported stranding occurrences in the region as shown in Figure 33. Most
of the stranding occurrences were concentrated in the months of April (2019, n=1; 2020, n=2), May
(2019, n=1; 2020, n=2), and June (2020, n=2). The rest of the months had only one occurrence each.
In terms of marine mammal species assemblage in the region, a total of 7 species were recorded.
There were 2 stranding occurrences for each species of an unidentified balaenopterid, short-finned
pilot whale, Indo-Pacific bottlenose dolphin, and Fraser’s dolphin (Figure 34). The strandings recorded
were all categorized as single events as shown in Figure 35.

38
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 28. DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN CENTRAL LUZON REGION.

39
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 29. NUMBER OF STRANDINGS WITHIN 15 X 15 KM FROM 2005 TO 2020 IN CENTRAL LUZON REGION.

40
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 30. STRANDINGS PER PROVINCE FROM 2019 AND 2020 IN CENTRAL LUZON REGION.
FIGURE 31. MONSOONAL DISTRIBUTION OF STRANDINGS FROM 2019 AND 2020 IN CENTRAL LUZON REGION.
1
3
4
3
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Aurora Bataan Zambales
Stranding frequency
Province
2019
2020
2
1 1 1
3
2
1
0
0.5
1
1.5
2
2.5
3
3.5
2019 2020 2019 2020 2019 2020
Aurora Bataan Zambales
Stranding frequency
Province
NE
Lull before SW
SW
Lull before NE

41
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 32. SEASONAL DISTRIBUTION OF STRANDINGS FROM 2019 AND 2020 IN CENTRAL LUZON REGION.
FIGURE 33. MONTHLY DISTRIBUTION OF STRANDINGS FROM 2019 AND 2020 IN CENTRAL LUZON REGION.
1
2
0
0.5
1
1.5
2
2.5
3
3.5
2019 2020 2019 2020 2019 2020
Aurora Bataan Zambales
Stranding frequency
Province
DJF
JJA
MAM
SON
1 1 1 1
2 2 2
1
0
0.5
1
1.5
2
2.5
Stranding frequency
Month
2019
2020

42
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 34. STRANDED MARINE MAMMAL SPECIES FROM 2019 AND 2020 IN CENTRAL LUZON REGION.
FIGURE 35. STRANDING EVENT CATEGORIES FROM 2019 TO 2020 IN CENTRAL LUZON REGION.
2
1
1
1
2
2
1
1
00.5 1 1.5 2 2.5 3
Unidentified balaenopterid
Short-finned pilot whale
Indo-Pacific bottlenose dolphin
Pantropical spotted dophin
Risso's dolphin
Dwarf sperm whale
Fraser's dolphin
Stranding frequency
Species
2019
2020
1
3
4
3
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
2019 2020 2019 2020 2019 2020
Aurora Bataan Zambales
Stranding frequency
Province
Single

43
Marine mammal strandings in the Philippines from 2019 to 2020
REGION IV-A (CALABARZON)
The CALABARZON region was one of the regions with the least stranding frequencies (n=8)
particularly, only 3 events in 2019 and 5 in 2020. The location of each stranding occurrence is shown
in Figure 36. There are 3 and 5 stranding incidences reported in 2019 and 2020, respectively. Of the 8
stranding occurrences in Region IV-A, 6 were documented in the province of Quezon and 2 in Batangas
(Figure 38).
Marine mammal stranding concentration from 2005 to 2020 in the region is shown in Figure 37. A
total of 32 15 x 15 km grids had stranding incidence recorded in this region. Of the 32 grids, 29 grids
had 1 to 4 stranding events, 3 grids had 5 to 8 stranding events, and no grid with more than or equal
to 9 stranding events.
Most of the stranding events in CALABARZON were recorded during the Northeast monsoon (n=4).
The Southwest and Inter-monsoon before SW season had the same number of stranding occurrences
(n=2). The distribution of stranding events per province per season is shown in Figure 39. In Quezon
province, stranding events recorded were at the maximum during the Northeast monsoon (n=3) in
2020, followed by the Winter Inter-monsoon in 2019 (n=1) and Southwest monsoon in 2020 (n=1).
Batangas had only 1 stranding case each reported during the Northeast monsoon and Winter Inter-
monsoon of 2019, and 1 case in the Southwest monsoon in 2020.
In the case of seasonal distribution (Figure 40), most standing cases in the region occurred in DJF
season (n=4) which were all documented in Quezon province. There were 2 cases during the MAM
season located in Batangas and Quezon. One incidence each occurred during JJA and SON season that
is found in Batangas and Quezon, respectively.
The general trend of marine mammal stranding per month in the region is shown in Figure 41. The
highest stranding events (n=2) were recorded in April and February. Only one stranding each was
documented in the months of January, April, August, September, and December; all these strandings
occurred in 2020.
In terms of species diversity in the CALABARZON region, there were only 5 marine mammal species
that have been recorded to strand (Figure 41). Pygmy sperm whale (Kogia breviceps) and Cuvier’s
beaked whale (Ziphius cavirostris) were the most frequent strander in the region. Each of these species
had 3 and 2 reported stranding cases, respectively. All stranding occurrences recorded in this region
were categorized as single events (Figure 43).

44
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 36. DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN CALABARZON REGION.

45
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 37. NUMBER OF STRANDINGS WITHIN 15 X 15 KM FROM 2005 TO 2020 IN CALABARZON REGION.

46
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 38. STRANDINGS PER PROVINCE FROM 2019 AND 2020 IN CALABARZON REGION.
FIGURE 39. MONSOONAL DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN CALABARZON REGION.
1
2
1
4
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Batangas Quezon
Stranding frequency
Province
2019
2020
1
3
1 11 1
0
0.5
1
1.5
2
2.5
3
3.5
2019 2020 2019 2020
Batangas Quezon
Stranding frequency
Province
NE
Lull before SW
SW
Lull before NE

47
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 40. SEASONAL DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN CALABARZON REGION.
FIGURE 41. MONTHLY DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN CALABARZON REGION.
1
3
11 1 1
0
0.5
1
1.5
2
2.5
3
3.5
2019 2020 2019 2020
Batangas Quezon
Stranding frequency
Province
DJF
JJA
MAM
SON
1
2
1 1 1 1 1
0
0.5
1
1.5
2
2.5
Stranding frequency
Month
2019
2020

48
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 42. STRANDED MARINE MAMMAL SPECIES FROM 2019 TO 2020 N CALABARZON REGION.
FIGURE 43. STRANDING EVENT CATEGORIES FROM 2019 TO 2020 IN CALABARZON REGION.
2
2
1
1
1
1
00.5 1 1.5 2 2.5 3
Cuvier's beaked whale
Pygmy sperm whale
Fraser's dolphin
Striped dolphin
Pantropical spotted dophin
Stranding frequency
Species
2019
2020
1 1
2
4
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
2019 2020 2019 2020
Batangas Quezon
Stranding frequency
Province
Single

49
Marine mammal strandings in the Philippines from 2019 to 2020
REGION IV-B (MIMAROPA)
The MIMAROPA Region had the 4th highest recorded stranding frequency from 2019 to 2020 (n=22).
Of the 22 stranding events, 14 occurred in 2019 and 8 in 2020. The locations of the stranding
incidences recorded for the past 2 years are shown in Figure 44. Apparently, Palawan was still the
hottest province region wide. It contributed the most in terms of the number of stranding cases
recorded in the region (n=10). There were more stranding events recorded in this province in 2019
(n=7) than in 2020 (n=3). On the contrary, Romblon (2019, n=1; 2020, n=1) and Marinduque (2019,
n=3) provinces had the least stranding contribution (Figure 46).
Areas where marine mammal strandings clustered are shown in Figure 45. A total of 43 grids had
stranding data. Of the 43 grids, 4 grids had 5 to 8 standing incidences recorded from 2005 to 2020.
These grids were in the municipalities of Puerto Princesa and Busuanga in Palawan and Looc and
Odiongan in Romblon. The rest of the grids had 1 to 4 stranding cases reported.
Stranding frequency in the region from 2019 to 2020 appeared to peak during the Southwest monsoon
(n=8) and lull before SW (n=7). On the other hand, fewer strandings were recorded during the
Northeast monsoon (n=5) and lull before NE (n=1). The province of Palawan followed the general
trend of monsoonal stranding variation of the region as shown in Figure 47. High stranding frequency
in this province was recorded during the Southwest monsoon in both 2019 and 2020 (n=3) and during
the lull before SW monsoon in 2019 (n=3). Occidental Mindoro followed Palawan in terms of
monsoonal distribution in Region IV-B. It had the highest stranding occurrences (n=3) during the
Northeast monsoon in 2020. Meanwhile, the province of Romblon had 2 stranding events, one of each
during the lull before SW and lull before NE. Marinduque had one stranding event reported during the
NE monsoon.
For seasonal distribution, most of the stranding events in the region occurred during the JJA and MAM
season (n=8; Figure 48). Both Palawan and Occidental Mindoro had cases in most seasons, with the
former having had the highest cases (n=3) during the JJA and MAM season. The latter had most cases
during the MAM season as well.
Additionally, the general trend of stranding events per month is shown in Figure 49. Strandings were
observed in almost all months, except in December. Most of the stranding events reported occurred
in the months of July (n=5), followed by May (n=4), and April (n=3).
In terms of species assemblage in the region, 10 species of marine mammals documented to strand
(Figure 50). Dugong (Dugong dugon) has been the most frequent species to strand for the past 2 years
(n=6). This frequency was less than half of the stranding occurrences of dugongs in the previous report
(Aragones et al. 2019). The Risso’s dolphin (Grampus griseus) and the pygmy sperm whale (Kogia
breviceps) were tied as the second most frequent stranders in the region with 3 records each. Most of
the recorded stranding incidences in the region involved single events (Figure 51). Only one mass
stranding event occurred in Occidental Mindoro in 2020 involving two adult Risso’s dolphins (Grampus
griseus).

50
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 44. DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN MIMAROPA REGION.

51
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 45. NUMBER OF STRANDINGS WITHIN 15 X 15 KM FROM 2005 TO 2020 IN MIMAROPA REGION.

52
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 46. STRANDINGS PER PROVINCE FROM 2019 TO 2020 IN MIMAROPA REGION.
FIGURE 47. MONSOONAL DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN MIMAROPA REGION.
1
3
7
3
1
4
3
0
1
2
3
4
5
6
7
8
Marinduque Occidental Mindoro Palawan Romblon
Stranding frequency
Province
2019
2020
1
3
1
2
3
2
1 1
3 3
1
0
0.5
1
1.5
2
2.5
3
3.5
2019 2020 2019 2020 2019 2020 2019 2020
Marinduque Occidental
Mindoro
Palawan Romblon
Stranding frequency
Province
NE
Lull before SW
SW
Lull before NE

53
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 48. SEASONAL DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN MIMAROPA REGION.
FIGURE 49. MONTHLY DISTRIBUTION OF STRANDINGS FROM 2019 AND 2020 IN MIMAROPA REGION.
1 11 1 1
3
22
1
3
2
1 1 1 1
0
0.5
1
1.5
2
2.5
3
3.5
2019 2020 2019 2020 2019 2020 2019 2020
Marinduque Occidental
Mindoro
Palawan Romblon
Stranding frequency
Province
DJF
JJA
MAM
SON
1
3
4
1
2
1 1 11 1
3
1 1 1
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Stranding frequency
Month
2019
2020

54
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 50. STRANDED MARINE MAMMAL SPECIES FROM 2019 TO 2020 IN MIMAROPA REGION.
FIGURE 51. STRANDING EVENT CATEGORIES FROM 2019 TO 2020 IN MIMAROPA REGION.
REGION V (BICOL REGION)
The Bicol Region remained the region with the highest number of reported stranding events from
2019 to 2020 together with Region I (n=26). Both years had a stranding frequency of 13. A map of the
2
1
1
1
1
1
1
4
2
2
2
1
1
1
1
012345
Dugong
Risso's dolphin
Pygmy sperm whale
Spinner dolphin
Short-finned pilot whale
Blainville's beaked whale
Rough-toothed dolphin
Pantropical spotted dophin
Omura's whale
Melon-headed whale
Stranding frequency
Species
2019
2020
1 1
3 3
7
3 3
1
0
1
2
3
4
5
6
7
8
2019 2020 2019 2020 2019 2020 2019 2020
Marinduque Occidental Mindoro Palawan Romblon
Stranding frequency
Province
Single
Mass

55
Marine mammal strandings in the Philippines from 2019 to 2020
spread of stranding incidences documented is shown in Figure 52. Among the provinces, Camarines
Sur had the highest number of strandings (n=7). It was followed by Camarines Norte (n=6), Masbate
(n=5), and Sorsogon (n=4). Catanduanes and Albay had the least number of stranding events (n=3 and
n=1, respectively; Figure 54).
The clusters of the recorded stranding events in the region from 2005 to 2020 is shown in Figure 53.
A total of 64 grids each with 15 x 15 km wide overlapped with stranding data. Six (6) of these grids had
5 to 8 stranding events which were in the municipalities of Mobo in Masbate, Donsol, Gubat, Bulusan,
and Pilar in Sorsogon, and Sto Domingo in Albay. One (1) grid had 9 to 12 stranding events located in
Del Gallego, Camarines Sur. The remaining grids had 1 to 4 stranding cases documented.
In terms of monsoonal distribution, high stranding frequency from 2019 to 2020 in the region was
recorded during the Northeast monsoon (n=13) followed by both Winter Inter-monsoon (n=5) and
Southwest monsoon (n=5). Camarines Sur had stranding events in all monsoons in which incidences
were highest during the Northeast monsoon (n=3). Furthermore, Northeast monsoon frequencies
were highest in the province of Camarines Norte (n=4). The only incident in Albay occurred during the
Northeast monsoon as well.
Majority of the stranding events in terms of seasonal distribution occurred during the SON season
(n=10). Subsequently, DJF had 7 strandings, MAM had 6, and JJA had 3. Camarines Sur had recorded
strandings in all seasons of consistent frequencies except during the JJA season. Camarines Norte and
Masbate similarly had strandings in three out of four seasons (Figure 56). In terms of monthly
distribution, stranding events were observed in almost all months except in the month of July. The
highest stranding event occurred in October (n=5), followed by the month of February (n=4), March
(n=3), and April (n=3; Figure 57).
A total of 14 marine mammal species have recorded to strand in the region (Figure 58). Spinner
dolphins (Stenella longirostris) had the highest stranding frequency documented (n=6). Additionally,
most of the stranding events in the region were categorized as single as shown in Figure 59. One (1)
out of habitat stranding event occurred in Brgy Bon-ot, San Andres Catanduanes which involved
melon-headed whales (Peponocephala electra).

56
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 52. DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN BICOL REGION.

57
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 53. NUMBER OF STRANDINGS WITHIN 15 X 15 KM FROM 2005 TO 2020 IN BICOL REGION.

58
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 54. STRANDINGS PER PROVINCE FROM 2019 TO 2020 IN BICOL REGION.
FIGURE 55. MONSOONAL DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN BICOL REGION.
3
5
2
3
1
3
2
1
2
4
0
1
2
3
4
5
6
Albay Camarines
Norte
Camarines
Sur
Catanduanes Masbate Sorsogon
Stranding frequency
Province
2019
2020
1
2 2 2
1 1 1
3
1 1 11 1
2
11
2
1 1
0
0.5
1
1.5
2
2.5
3
3.5
2019 2020 2019 2020 2019 2020 2019 2020 2019 2020 2019 2020
Albay Camarines
Norte
Camarines
Sur
Catanduanes Masbate Sorsogon
Stranding frequency
Province
NE
Lull before SW
SW
Lull before NE

59
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 56. SEASONAL DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN BICOL REGION.
FIGURE 57. MONTHLY DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN BICOL REGION.
1 1
2
3
1 1 11
2
1
2
1
2
1
2 2
1 1
0
0.5
1
1.5
2
2.5
3
3.5
2019 2020 2019 2020 2019 2020 2019 2020 2019 2020 2019 2020
Albay Camarines
Norte
Camarines
Sur
Catanduanes Masbate Sorsogon
Stranding frequency
Province
DJF
JJA
MAM
SON
1
2
1
2 2
4
11
2 2 2
1 1 1
2
1
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Stranding frequency
Month
2019
2020

60
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 58. STRANDED MARINE MAMMAL SPECIES FROM 2019 TO 2020 IN BICOL REGION.
FIGURE 59. STRANDING EVENT CATEGORIES FROM 2019 TO 2020 IN BICOL REGION.
3
1
1
2
1
1
2
2
3
2
1
1
1
1
1
1
1
1
01234
Spinner dolphin
Indo-Pacific bottlenose dolphin
Short-finned pilot whale
Sperm whale
Common bottlenose dolphin
Cuvier's beaked whale
Pantropical spotted dophin
Dwarf sperm whale
Dugong
Pygmy sperm whale
Bryde's whale
Striped dolphin
Melon-headed whale
Risso's dolphin
Stranding frequency
Species
2019
2020
1
3 3
5
2 2
3
2
4
1
0
1
2
3
4
5
6
2019 2020 2019 2020 2019 2020 2019 2020 2019 2020 2019 2020
Albay Camarines
Norte
Camarines
Sur
Catanduanes Masbate Sorsogon
Stranding frequency
Province
Single
Out of habitat

61
Marine mammal strandings in the Philippines from 2019 to 2020
REGION VI (WESTERN VISAYAS)
Western Visayas Region had the second highest number of reported stranding cases nationwide from
2019 to 2020 (n=25; see Table 3). There were 13 stranding events recorded in 2019 and 12 events in
2020. The locations of these stranding events from 2019 to 2020 are shown in Figure 60. Of the 25
stranding events recorded in the region, majority were in Negros Occidental (n=10) and 6 occurrences
in Aklan. There are 3 stranding events in both Antique and Iloilo, two in Guimaras, and one in Capiz
(Figure 62).
Clusters of stranding incidences reported in the region from 2005 to 2020 are shown in Figure 61. A
total of 35 grids (15 x 15 km) contained stranding events. Three (3) of the 35 grids recorded 5 to 8
stranding occurrences. One (1) grid had 9 to 12 stranding occurrences located in Bago City, Negros
Occidental. The rest of the grids had 1 to 4 stranding frequency.
In terms of monsoonal periods, most of the stranding events occurred during the Northeast monsoon
(n=12), followed by the Southwest monsoon (n=8). There were 4 stranding events during the Winter
Inter-monsoon and 1 stranding event during the Spring Inter-monsoon. In provincial level by season
as shown in Figure 63, the highest frequency occurred during the Northeast (n=5) and Southwest
monsoon (n=4) in Negros Occidental. Aklan consistently had stranding events in all seasons while Capiz
with one stranding event occurred during the Southwest monsoon.
By seasonality, it is evident in Figure 64 that most of the stranding events occurred during the MAM
(n=8) and DJF (n=7) seasons. Five (5) events occurred during the JJA and SON season each. Most cases
in Negros Occidental occurred during the DJF season. Furthermore, stranding events in the province
occurred in all seasons.
The general trend of marine mammal stranding in the region per month is shown in Figure 65. As can
be observed, stranding events were highest (n=4) in the months of January, March, and July. No
stranding event was recorded in the month of June.
There was a total of 12 marine mammal species that have been recorded to strand along the coastline
of the region (Figure 66). Dugong (Dugong dugon) was recorded to be the most frequent strander in
the region for the past two years (n=6). These stranding events were primarily categorized as single
as shown in Figure 67. There were two mass stranding events reported in the region. One event was
documented in 2019 in Brgy. Gargato, Hinigaran in Negros Occidental wherein three (3) calves of
pygmy killer whale (Feresa attenuata) were found to strand. The second event was recorded in Brgy
Guinsang-an, Hamtic Antique in 2020. Two (2) adult female short-finned pilot whales (Globicephala
macrorhynchus) were recorded to strand in the area.

62
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 60. DISTRIBUTION OF STRANDINGS FROM 2019 AND 2020 IN WESTERN VISAYAS REGION.

63
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 61. NUMBER OF STRANDINGS WITHIN 15 X 15 KM FROM 2005 TO 2020 IN WESTERN VISAYAS REGION.

64
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 62. STRANDINGS PER PROVINCE FROM 2019 TO 2020 IN WESTERN VISAYAS REGION.
FIGURE 63. MONSOONAL DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN WESTERN VISAYAS REGION.
3
1 1
2
6
3
2 2
1
4
0
1
2
3
4
5
6
7
Aklan Antique Capiz Guimaras Iloilo Negros
Occidental
Stranding frequency
Province
2019
2020
1
2
1 1 1 1
2
3
1 1 1 11 1 1 1
3
11
0
0.5
1
1.5
2
2.5
3
3.5
2019 2020 2019 2020 2019 2020 2019 2020 2019 2020 2019 2020
Aklan Antique Capiz Guimaras Iloilo Negros
Occidental
Stranding frequency
Province
NE
Lull before SW
SW
Lull before NE

65
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 64. SEASONAL DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN WESTERN VISAYAS REGION.
FIGURE 65. MONTHLY DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN WESTERN VISAYAS REGION.
1 1 1
2 2
1 1 1
22
1 1 1 1 1 11 1 1 1 1
0
0.5
1
1.5
2
2.5
2019 2020 2019 2020 2019 2020 2019 2020 2019 2020 2019 2020
Aklan Antique Capiz Guimaras Iloilo Negros
Occidental
Stranding frequency
Province
DJF
JJA
MAM
SON
1
2 2
1
2 2
1 1 1
3
2
1
2 2
1 1
0
0.5
1
1.5
2
2.5
3
3.5
Stranding frequency
Month
2019
2020

66
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 66. STRANDED MARINE MAMMAL SPECIES FROM 2019 TO 2020 IN WESTERN VISAYAS REGION.
FIGURE 67. STRANDING EVENT CATEGORIES FROM 2019 TO 2020 IN WESTERN VISAYAS REGION.
3
2
4
1
5
2
1
1
1
1
1
1
0 1 2 3 4 5 6
Spinner dolphin
Dwarf sperm whale
False killer whale
Melon-headed whale
Indo-Pacific bottlenose dolphin
Common bottlenose dolphin
Risso's dolphin
Fraser's dolphin
Short-finned pilot whale
Pygmy killer whale
Stranding frequency
Species
2019
2020
3 3
1 1 1
2 2
1
5
4
1 1
0
1
2
3
4
5
6
2019 2020 2019 2020 2019 2020 2019 2020 2019 2020 2019 2020
Aklan Antique Capiz Guimaras Iloilo Negros
Occidental
Stranding frequency
Province
Single
Mass

67
Marine mammal strandings in the Philippines from 2019 to 2020
REGION VII (CENTRAL VISAYAS)
The Central Visayas region ranked 3rd highest in terms of stranding frequency for 2019 to 2020 (see
Table 3). The region had a total of 23 stranding events reported for that period. Thirteen (13) occurred
in the year 2019 while the 10 events occurred in 2020. The locations of the stranding cases reported
are shown in Figure 68. The province of Cebu had the most stranding incidents in the region (n=9), 8
events were documented in 2019 and one event in 2020. It was followed by Negros Oriental and Bohol
with 7 and 5 total stranding frequency, respectively. Siquijor had a total of 2 recorded stranding events
(Figure 70).
The clustering of areas where marine mammals stranded in Region VII from 2005 to 2020 are shown
in Figure 69. A total of 43 grids that overlapped with marine mammal stranding events. Most of these
grids had 1 to 4 stranding records (n=35) and 8 grids had 5 to 8 stranding events. The 8 areas indicated
by the 15 x 15 km grid with 5 to 8 stranding incidences were in Siquijor and Larena in Siquijor,
Dumaguete City, San Jose, and Dauin in Negros Oriental, Baclayon in Bohol, and Talisay City and Lapu
Lapu City in Cebu.
Most of the stranding events recorded from 2019 to 2020 in the region occurred during the Northeast
monsoon (n=10), followed by a lull before SW (n=7). Five (5) strandings were recorded during the
Southwest monsoon, while there was one recorded event during the lull before NE. The stranding
incidence reported in Cebu occurred during the Northeast (n=4), Southwest (n=3), and lull before SW
(n=2) monsoons. Five (5) stranding events during lull before SW and 2 during the Northeast monsoon
occurred in Negros Oriental. Two (2) of the stranding cases in Siquijor occurred during the Northeast
monsoon (Figure 71).
The seasonal distribution in the region is shown in Figure 72. Majority of the stranding cases were
found during the MAM season (n=12). Five (5) of the events occurred during the DJF season, 4 during
the JJA season, and 2 during the SON season. Six (6) of the 9 strandings in Cebu were documented
during the MAM season and the rest during the JJA season. In Negros Oriental, 5 strandings occurred
during the MAM season and 2 during the DJF season.
High stranding cases in this region in the months of March (n=5) and April (n=5) can be observed in
Figure 64. There were 3 cases each in the months of February and June. No strandings occurred in
July, November, and December (Figure 73)
In terms of species composition, a total of 9 marine mammal species were recorded to strand in the
region (Figure 74). The Spinner dolphin (Stenella longirostris, n=5) and the Fraser’s dolphin
(Lagenodelphis hosei, n=5) had the highest frequency recorded among the other species. In addition,
most of the recorded stranding incidences in the region were categorically single events (Figure 75).

68
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 68. DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN CENTRAL VISAYAS REGION.

69
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 69. NUMBER OF STRANDINGS WITHIN 15 X 15 KM FROM 2005 TO 2020 IN CENTRAL VISAYAS REGION.

70
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 70. STRANDINGS PER PROVINCE FROM 2019 TO 2020 IN CENTRAL VISAYAS REGION.
FIGURE 71. MONSOONAL DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN CENTRAL VISAYAS REGION.
1
8
3
1
4
1
4
1
0
1
2
3
4
5
6
7
8
9
Bohol Cebu Negros Oriental Siquijor
Stranding frequency
Province
2019
2020
1 1
4
1 1 1 11 1
2
3
2
3
1
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
2019 2020 2019 2020 2019 2020 2019 2020
Bohol Cebu Negros Oriental Siquijor
Stranding frequency
Province
NE
Lull before SW
SW
Lull before NE

71
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 72. SEASONAL DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN CENTRAL VISAYAS REGION.
FIGURE 73. MONTHLY DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN CENTRAL VISAYAS REGION.
1 1 1 1 11
3
5
1
2
3
1
2
0
1
2
3
4
5
6
2019 2020 2019 2020 2019 2020 2019 2020
Bohol Cebu Negros Oriental Siquijor
Stranding frequency
Province
DJF
JJA
MAM
SON
1 1
5
2
1
3
1
2
3
1 1 1 1
0
1
2
3
4
5
6
Stranding frequency
Month
2019
2020

72
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 74. STRANDED MARINE MAMMAL SPECIES FROM 2019 TO 2020 IN CENTRAL VISAYAS REGION.
FIGURE 75. STRANDING EVENT CATEGORIES FROM 2019 TO 2020 IN CENTRAL VISAYAS REGION.
3
2
4
1
5
2
1
1
1
1
1
0123456
Spinner dolphin
Dwarf sperm whale
False killer whale
Melon-headed whale
Indo-Pacific bottlenose dolphin
Common bottlenose dolphin
Risso's dolphin
Fraser's dolphin
Short-finned pilot whale
Stranding frequency
Species
2019
2020
1
4
8
1
3
4
1 1
0
1
2
3
4
5
6
7
8
9
2019 2020 2019 2020 2019 2020 2019 2020
Bohol Cebu Negros Oriental Siquijor
Stranding frequency
Province
Single

73
Marine mammal strandings in the Philippines from 2019 to 2020
REGION VIII (EASTERN VISAYAS)
The Eastern Visayas had a total of 16 stranding events recorded from 2019 to 2020. This region ranked
as 5th highest stranding frequency. There were relatively higher stranding reports in 2019 (n=9) than
in 2020 (n=7). The locations of these reported stranding cases are shown in Figure 76. The province of
Southern Leyte had the highest number of stranding records (n=6) among all the provinces in Region
VIII. It was followed by Leyte (n=4), Samar (n=3), Northern Samar (n=2), and Biliran (n=1). Stranding
frequencies in Southern Leyte were consistent in the past two years, while Leyte peaked in the year
2019 (Figure 78). The only stranding incident documented in Biliran occurred in 2020.
Stranding occurrences documented from 2005 to 2020 in the region was mapped and the
concentration within the 15 x 15 km grid is shown in Figure 77. There were no stranding hotspots in
the region. All 32 grids had 1 to 4 stranding reports recorded.
High stranding frequency from 2019 to 2020 was observed during the Southwest monsoon (n=7),
followed by the Northeast monsoon (n=5), and lull before SW (n=4). The seasonal stranding
distribution per province is shown in Figure 79. Most stranding events in Southern Leyte and Leyte
occurred during the Southwest monsoon.
Meanwhile, by seasonality, the MAM season had the highest stranding frequency (n=7). Subsequently,
the JJA season had 4 stranding events, SON season had 3, and the DJF season had 2. Both Southern
Leyte and Biliran had standings in all seasons across the two-year period. Southern Leyte had the
maximum frequencies during the MAM and SON seasons (Figure 80).
Figure 81 shows the monthly trends from 2019 to 2020 in the region. It can be observed that stranding
events were highest in the months of March (n=3), April (n=3), and September (n=3). No strandings
occurred in January, June, October, November, and December.
Marine mammal species recorded to strand in Eastern Visayas are shown in Figure 82. There were 7
species documented that had stranded in the region. Spinner dolphin (Stenella longirostris) was
considered the most frequent strander (n=6), followed by melon-headed whale (Peponocephala
electra; n=3). Additionally, most of the stranding incidents recorded in the region were categorized as
single events as shown in Figure 83.

74
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 76. DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN EASTERN VISAYAS REGION.

75
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 77. NUMBER OF STRANDINGS WITHIN 15 X 15 KM FROM 2005 TO 2020 IN EASTERN VISAYAS REGION.

76
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 78. STRANDINGS PER PROVINCE FROM 2019 TO 2020 IN EASTERN VISAYAS REGION.
FIGURE 79. MONSOONAL DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN EASTERN VISAYAS REGION.
3
2
1
3
1 1
2
3
0
0.5
1
1.5
2
2.5
3
3.5
Biliran Leyte Northern Samar Samar Southern Leyte
Stranding frequency
Province
2019
2020
1 1 1
2
1 1 1 11
2
1
3
0
0.5
1
1.5
2
2.5
3
3.5
2019 2020 2019 2020 2019 2020 2019 2020 2019 2020
Biliran Leyte Northern
Samar
Samar Southern Leyte
Stranding frequency
Province
NE
Lull before SW
SW
Lull before NE

77
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 80. SEASONAL DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN EASTERN VISAYAS REGION.
FIGURE 81. MONTHLY DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN EASTERN VISAYAS REGION.
1 11 1 1 11
2
1 1
2
1
2
0
0.5
1
1.5
2
2.5
2019 2020 2019 2020 2019 2020 2019 2020 2019 2020
Biliran Leyte Northern Samar Samar Southern Leyte
Stranding frequency
Province
DJF
JJA
MAM
SON
2
3
1 1 1 1
2 2
1
2
0
0.5
1
1.5
2
2.5
3
3.5
Stranding frequency
Month
2019
2020

78
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 82. STRANDED MARINE MAMMAL SPECIES FROM 2019 TO 2020 IN EASTERN VISAYAS REGION.
FIGURE 83. STRANDING EVENT CATEGORIES FROM 2019 TO 2020 IN EASTERN VISAYAS REGION.
2
2
1
1
1
4
2
1
1
1
012345
Spinner dolphin
Fraser's dolphin
Melon-headed whale
Dwarf sperm whale
Pygmy sperm whale
Indo-Pacific bottlenose dolphin
Cuvier's beaked whale
Stranding frequency
Species
2019
2020
1
3
1
2
1
2
3 3
0
0.5
1
1.5
2
2.5
3
3.5
2019 2020 2019 2020 2019 2020 2019 2020 2019 2020
Biliran Leyte Northern
Samar
Samar Southern Leyte
Stranding frequency
Province
Single

79
Marine mammal strandings in the Philippines from 2019 to 2020
REGION IX (ZAMBOANGA PENINSULA)
The Zamboanga Peninsula ranked 8th highest in terms of stranding frequencies among regions,
together with Region 4A for 2019 to 2020 (see Table 3). There were 8 stranding cases reported in the
region which mostly occurred in 2020 (n=5). The locations of these events were shown in Figure 84.
The province of Zamboanga del Sur contributed the most in terms of reported stranding incidence in
the region (n=4), with all cases occurring in 2020. It is followed by Zamboanga del Norte (n=3) and
Zamboanga Sibugay (n=1; Figure 86).
Areas where stranded marine mammals clustered are shown in Figure 85. Twenty-three (23) grids
with 15 x 15 km wide had stranding records from 2005 to 2020. Three (3) grids had 5 to 8 strandings
located in Zamboanga City, Zamboanga del Sur. One (1) grid had 9 to 12 cases which occurred in
Zamboanga City as well. The rest of the grids had only 1 to 4 stranding cases documented.
In terms of monsoonal patterns of strandings from 2019 to 2020, a total of 4 and 3 incidents of marine
mammals washed ashore during the Northeast and Southwest monsoons, respectively. Three out of
four strandings in Zamboanga del Sur occurred during the Northeast monsoon and the rest occurred
during the Southwest monsoon, both of which in 2020. Only 1 stranding incident occurred during the
Winter Inter-monsoon, which was found in Zamboanga Sibugay (Figure 87).
The most notable trend in the seasonal distribution per province was each stranding event that
occurred in Zamboanga del Sur was evenly distributed across seasons in 2020 (Figure 88). The general
distribution of stranding per month was shown in Figure 89. Stranding during the month of March
(n=2) was recorded to be the highest frequency.
A total of seven (7) marine mammal species have been found to strand in the Zamboanga Peninsula
region (Figure 90). The Risso’s dolphin (Grampus griseus) was the most frequent (n=2). The rest of the
recorded species had one each stranding event across the two-year period, which mostly occurred in
2020.
Most of the stranding incidents involving different species were categorized as single type as shown
in Figure 91. One event was classified as out of habitat in the region. This event involved a Risso’s
dolphin (Grampus griseus) in NSRE Beach, Calarian, Zamboanga City.

80
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 84. DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN ZAMBOANGA PENINSULA REGION.

81
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 85. NUMBER OF STRANDINGS WITHIN 15 X 15 KM FROM 2005 TO 2020 IN ZAMBOANGA PENINSULA.

82
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 86. STRANDINGS PER PROVINCE FROM 2019 TO 2020 IN ZAMBOANGA PENINSULA.
FIGURE 87. MONSOONAL DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN ZAMBOANGA PENINSULA.
2
11
4
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Zamboanga del Norte Zambuanga Sibugay Zamboanga del Sur
Stranding frequency
Province
2019
2020
1
3
11 1 1
0
0.5
1
1.5
2
2.5
3
3.5
2019 2020 2019 2020 2019 2020
Zamboanga del Norte Zambuanga Sibugay Zamboanga del Sur
Stranding frequency
Province
NE
Lull before SW
SW
Lull before NE

83
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 88. SEASONAL DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN ZAMBOANGA PENINSULA REGION.
FIGURE 89. MONTHLY DISTRIBUTION OF STRANDINGS FROM 2019 TO 2020 IN ZAMBOANGA PENINSULA REGION.
11 1 11 1 1 1
0
0.2
0.4
0.6
0.8
1
1.2
2019 2020 2019 2020 2019 2020
Zamboanga del Norte Zambuanga Sibugay Zamboanga del Sur
Stranding frequency
Province
DJF
JJA
MAM
SON
1 1 11 1 1 1 1
0
0.2
0.4
0.6
0.8
1
1.2
Stranding frequency
Month
2019
2020

84
Marine mammal strandings in the Philippines from 2019 to 2020
FIGURE 90. STRANDED MARINE MAMMAL SPECIES FROM 2019 TO 2020 IN ZAMBOANGA PENINSULA REGION.
FIGURE 91. STRANDING EVENT CATEGORIES FROM 2019 TO 2020 IN ZAMBOANGA PENINSULA REGION.
1
1
1
1
1
1
1
1
0 0.5 1 1.5 2
Short-finned pilot whale
False killer whale
Melon-headed whale
Risso's dolphin
Fraser's dolphin
Pygmy sperm whale
Spinner dolphin
Stranding frequency
Species
2019
2020
2
1 1
3
1
0
0.5
1
1.5
2
2.5
3
3.5
2019 2020 2019 2020 2019 2020
Zamboanga del Norte Zambuanga Sibugay Zamboanga del Sur
Stranding frequency
Province
Single
Out of habitat

85
Marine mammal strandings in the Philippines from 2019 to 2020
REGION X (NORTHERN MINDANAO)
Northern Mindanao ranked 9th in terms of stranding frequency nationwide from 2019 to 2020 (n=5).
Stranding cases reported in the region were higher in 2019 (n=4) than in 2020 (n=1). The distribution
of these events was shown in Figure 92. On a provincial level, both Misamis Oriental and Camiguin
had higher strandings (n=2) compared to Lanao del Norte (n=1; Figure 94).
Concentration of marine mammal stranding recorded from 2005 to 2020 is shown in Figure 93. A total
of 16 grids along the coastline of Northern Mindanao had stranding records. Most of these grids had
1 to 4 stranding incidences reported. The only grid with 5 to 8 stranding reports was in Cagayan de
Oro City, Misamis Oriental.
Stranding frequencies in the region from 2019 to 2020 based on monsoonal distribution can be
observed in Figure 95. Most strandings were recorded during the Northeast monsoon. Each stranding
in Camiguin occurred during lull before SW and lull before NE. Similarly, each stranding event in
Misamis Oriental occurred in different seasons (Northeast and Southwest monsoons). The only
stranding event in Lanao del Norte was observed to occur during the Northeast monsoon.
In terms of seasonal distribution, most of the strandings occurred during the MAM season (n=2). The
rest occurred evenly in all seasons (Figure 96). Stranding events that occurred during the MAM season
were found in Camiguin and Misamis Oriental.
Stranding distribution per month is shown in Figure 97. One stranding event each occurred in the
months of February, March, April, August, and October. The one stranding event that occurred in 2020
occurred in August.
Three marine mammal species have been recorded to strand in the region in the past 2 years (Figure
98). The spinner dolphin (Stenella longirostris) was the most frequent strander (n=3). One individual
of common bottlenose dolphin (Tursiops truncatus) and Fraser’s dolphin (Lagenodelphis hosei) was
also found to strand in the region. In addition, most of the recorded stranding incidences in the region
involved single events (Figure 99).