Philippine Journal of Science Vol. 145 No. 3, September 2016 of prawn (Macrobrachium rosenbergii) and tiger shrimp (Penaeus monodon) (Ahmed 2013). Effects on Coral Reefs and Associated Species Corals have relatively fixed thermal limits and only capable of tolerating a narrow range of temperature, thus, making them the first to be severely damaged from fluctuating water temperatures (Coles et al. 1976). They are central to reef ecosystems: support and protect all sorts of organisms in the reef, contribute to primary production, play a major role in nutrient cycling and reef growth (Hoegh-Guldberg 2004; Wild et al. 2004). Corals reefs are the most diverse marine environment and without these species, a great portion of the sea bed is basically empty. Therefore, destruction of these organisms reduces the diverse assemblages of marine organisms and disrupts interconnected relationships in the ecosystem (Meuser et al. 2013). The increased sea surface temperatures brought about by extreme events such as El Niño have pronounced effects on the corals (Reaser et al. 2000). In the EEP, El Niño causes widespread and moderate to severe episodes of coral bleaching due to warm water intrusion (Glynn, 1984; Glynn & D’Croz 1990; Stone et al. 1999). Moderate bleaching reduces the survival of corals, while severe bleaching ultimately follows coral death (Doney et al. 2012). The corals in the EEP are profoundly affected by El Niño since they are directly submerged to anomalous warm water from the EWP. In the EWP, while sea surface temperature becomes cooler, lower sea level leaves corals from low tides and can cause mortality due to exposure to the air and high irradiance (Glynn 1996; Anthony & Kerswell 2007). Although the effects of El Niño are more pronounced in the EEP, coral bleaching in the EWP have also been attributed to El Niño events. In 1982/1983, coral bleaching coincided with El Niño and was reported in Costa Rica, Great Barrier Reef, Java Sea, Polynesia, Galapagos Islands, Pacific coast of Panama and Colombia, southwestern Indian Ocean, southern Japan, the Caribbean, Florida and Bahama Islands (Glynn 1984; Coffroth et al. 1990). In the Philippines, bleaching was recorded in Alcoy reef in 1981 and Hilatagan Island in 1982. In 1997/1998, coral bleaching and mortality were recorded in India, Sri Lanka, Maldives, Kenya, Tanzania, southern Japan and other Indo-Pacific countries (Wilkinson et al. 1999; Fitt et al. 2001). In the Philippines, coral mortality due to bleaching resulted to a 46% reduction in live coral cover of the country (Capili et al. 2005). Bleaching affects the structure and dynamics of coral reef ecosystems as bleached sites in the country showed lower recruitment of reef-associated fishes as compared to unbleached and recovered areas (Booth & Beretta 2002; Capili et al. 2005). 288 Damatac II & Santos: Possible Effects of El Niño on Some Philippine Marine Fisheries Resources Bleached site may recover, however, it takes a long time to restore the reef back to its former state. Brown and Suharsono (1990) observed that an extensive bleached site in Thousand islands, Indonesia was able to recover after five years although the coral cover was still half of its state before the bleaching event. Effects on Seaweeds Like corals, seaweeds are good indicators of the effects of El Niño because they are directly subjected to changes in the Pacific where many species are confined. Temperature and salinity are ecological factors that generally affect the physiology, reproduction, development and distribution of seaweeds (Breeman 1988; Breeman 1990; Steen 2004). Some seaweeds can tolerate wide ranges of temperature and salinity, while some cannot depending on the species. In the EEP, the sea level rise during El Niño can result to upward shift in the distribution of seaweeds (Harley et al. 2012) while lower salinity can reduce their survival (Steen 2004). The 1997/1998 El Niño caused the disappearance of giant kelps in their northeast Pacific range (Edwards, 2004). Grove et al. (2002) also linked the same event to the low kelp density in Southern California due to prolonged warm water surface temperature and more frequent rainfall. In the EWP, the decrease in sea level can expose and destroy the upper layers of intertidal seaweed communities and experience desiccation, high irradiance, and osmotic stress (Davidson & Pearson 1996; Ji & Tanaka 2002). Although there is a direct relationship between seaweed vertical distribution and their stress tolerances, the extreme conditions have obviously lethal effects on the upper benthic communities (Davidson & Pearson 1996). Water loss due to exposure from air and heat decreases seaweed photosynthetic and respiration rates (Ji & Tanaka 2002) while drought can further reduce these metabolic processes. They can shift their distribution downward, however, this depends on the presence of a suitable substrate. El Niño events may affect the survival of seaweeds in many coastal farms, which puts risk on the position of the Philippines as one of the producers of aquatic plants. Trono and Valdestamon (1994) reported a disease called “ice-ice” in Eucheuma sp. and Kappaphycus sp. which occurs during dry months when exposed to heat and high salinity. These seaweeds produce a moist substance under stress that attracts bacteria and causes the whitening and hardening of branches. An outbreak of the disease can occur when seaweeds exceed their optimal temperature of 28-32 °C and salinity of 30-35 ppt. The cultured seaweeds located at shallower portion of the coastal areas can be most affected when extreme heat occur during an El Nino.