Over 30 years of HABs in the Philippines and Malaysia: What have we learned?

Yniguez, Aletta T. and Lim, Po Teen and Leaw, Chui Pin and Jipanin, Steffiana J. and Iwataki, Mitsunori and Benico, Garry and Azanza, Rhodora (2021) Over 30 years of HABs in the Philippines and Malaysia: What have we learned? Harmful Algae, 102 (SI). ISSN 1568-9883, DOI https://doi.org/10.1016/j.hal.2020.101776.

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In the Southeast Asian region, the Philippines and Malaysia are two of the most affected by Harmful Algal Blooms (HABs). Using long-term observations of HAB events, we determined if these are increasing in frequency and duration, and expanding across space in each country. Blooms of Paralytic Shellfish Toxin (PST)-producing species in the Philippines did increase in frequency and duration during the early to mid-1990s, but have stabilized since then. However, the number of sites affected by these blooms continue to expand though at a slower rate than in the 1990s. Furthermore, the type of HABs and causative species have diversified for both toxic blooms and fish kill events. In contrast, Malaysia showed no increasing trend in the frequency of toxic blooms over the past three decades since Pyrodinium bahamense was reported in 1976. However, similar to the Philippines, other PST producers such as Alexandrium minutum and Alexandrium tamiyavanichii have become a concern. No amnesic shellfish poisoning (ASP) has been confirmed in either Philippines or Malaysia thus far, while ciguatera fish poisoning cases are known from the Philippines and Malaysia but the causative organisms remain poorly studied. Since the 1990s and early 2000s, recognition of the distribution of other PST-producing species such as species of Alexandrium and Gymnodinium catenatum in Southeast Asia has grown, though there has been no significant expansion in the known distributions within the last decade. A major more recent problem in the two countries and for Southeast Asia in general are the frequent fish-killing algal blooms of various species such as Prorocentrum cordatum, Margalefidinium polykrikoides, Chattonella spp., and unarmored dinoflagellates (e. g., Karlodinium australe and Takayama sp.). These new sites affected and the increase in types of HABs and causative species could be attributed to various factors such as introduction through mariculture and eutrophication, and partly because of increased scientific awareness. These connections still need to be more concretely investigated. The link to the El Nin?o Southern Oscillation (ENSO) should also be better understood if we want to discern how climate change plays a role in these patterns of HAB occurrences.

Item Type: Article
Funders: Highest Institution Centre of Excellence Grant from the Malaysian Ministry of Education[IOES-2014C], Highest Institution Centre of Excellence Grant from the Malaysian Ministry of Education[TU001A-2018], Ministry of Energy, Science, Technology, Environment and Climate Change[CF001-2018], Philippine Department of Science and Technology Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (DOST PCAARRD)
Uncontrolled Keywords: Harmful algal blooms;Southeast Asia;Dinoflagellates;Paralytic shellfish poisoning;Ciguatera Fish Poisoning;Fish kills
Subjects: G Geography. Anthropology. Recreation > GC Oceanography
G Geography. Anthropology. Recreation > GE Environmental Sciences
Divisions: Deputy Vice Chancellor (Research & Innovation) Office > Institute of Ocean and Earth Sciences
Depositing User: Ms Zaharah Ramly
Date Deposited: 18 Aug 2022 02:54
Last Modified: 18 Aug 2022 02:54
URI: http://eprints.um.edu.my/id/eprint/28846

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