The Effects of Red Tide to the Capiznon

Chapter I

The effects of Red Tide to the Capiznon

Introduction

       Red tide is a seawater discovered by the presence of large numbers of din flagellates which produce a toxin poisonous especially in many forms of marine vertebrate life and to humans who consume contaminated shellfish. In many aquatic ecosystems not influenced by Man, Harmful Algal Blooms including those of cyanobacteria, are normal phenomena. However, blooms of algae causing detrimental effects on aquatic ecosystems, such as water discoloration, health problems due to intoxicated fish, shellfish etc. as well as direct toxicity to fauna, including fish kills and human fatalities (the latter due to consumption of microalgae toxins accumulated in shellfish) are for sure a disturbance for the aquatic ecosystems where they occur. Algae or microscopic plants that float on the surface of water bodies such as oceans, lakes and rivers. In the ocean, algal communities constitute the base of the marine food web. Algal blooms are biological phenomena associated with high cell concentrations of phytoplankton. Since phytoplankton form the base of the marine food web, algal blooms have close relationship with the oceanic primary production. The detection and monitoring of these blooms are often considered as a viable means for locating new fishing grounds. Thus, algal bloom monitoring has a positive impact on countries engaged in marine fishing. However, not all algal blooms are beneficial to humans. Often the terms ‘Paralytic Shellfish Poisoning (PSP)' is one of the four recognized syndromes of shellfish poisoning, which share some common features and are primary associated with bivalve mollusks (such as mussels, clams, oysters and scallops).

A.)Background

Many of the red tides (i.e., Paralytic Shellfish Poison) in the Municipality of Pilar, Sapian, President Roxas and Ivisan Capiz. These shellfish are filter feeders and, therefore, accumulate neurotoxins, called saxitoxin, produced by microscopic algae, such as dinoflagellates of the genus Alexandriumare the most numerous and widespread saxitoxin producers and are responsible for PSP blooms in subarctic, temperate, and tropical locations.  The majority of toxic blooms have been caused by the morphospecies Alexandrium catenella, Alexandrium tamarense and Alexandrium fundyense which together comprise the A. tamarense species complex. In Asia, PSP is mostly associated with the occurrence of the species Pyrodinium bahamense. Human toxicity and mortality can occur after ingestion of these animals, but toxicity is also seen in wild animal populations. According to the Bureau of Fisheries and Aquatic Resources (BFAR) the seafood from the four towns of Pilar, Sapian, President Roxas and Ivisan Capiz are positive in the paralytic shellfish poison in that area. Based on the latest laboratory result of BFAR, appeared that the exceeded regulatory limit of paralytic shellfish poison in the town of President Roxas is the reason why to do the shellfish ban in that town. Meanwhile, it remains safe from red tide in the area of Baybay beach in Roxas City and its nearby towns. Despite many months of community efforts, the mechanisms of initiation, maintenance and demise of red tides are still poorly understood and require further investigation.

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