Harmful Algal Bloom (HAB or Harmful Algal Blooms –HABs) is a biological phenomenon that occurs naturally as a result of the combination of physical, chemical, and biological mechanisms, for example, as a consequence of hydrographic processes as surge, contact fronts between two water masses of different density, salinity, or temperature, or by anthropogenic changes.

HAB events and phytoplankton blooming are produced by several microalgal species; those that stand out are dinoflagellates for the diversity of species involved.

The effects caused by red tides in fishery resources or in mollusk or fish cultures could be devastating, both from an economic viewpoint and from the physiological damage they can cause to organisms. To have an idea of the impact HAB has in marine ecosystems, massive deaths have been registered only in the State of Baja California Sur and the Gulf of California, such as those of sea lions, pelicans, mollusks, lobsters, and fish (among others), in which the causal agent has been identified as HAB. In the case of marine mammals and birds, death has been the consequence of intoxication, and in the case of fish either by intoxication or asphyxia due to the destruction of available dissolved oxygen because of the high density of microalgal presence. For example, the red tide that occurred during August-September 2007 in the area of Punta Abreojos had a significant impact in the main fishery and aquaculture resources of commercial priority, such as abalone, lobster, winkle, Pismo clam, and cultured oyster, among others, besides a large variety of scale species.

Marine toxin effect in the metabolism of marine mollusks has been poorly documented. However, to understand its impact in the ecosystems and in fisheries, it is necessary to know the subsequent metabolic details to acute and sub-chronic exposure to organisms that produce marine toxins type DSP (Diarrhetic Shellfish Poisoning) and PSP (Paralytic Shellfish Poisoning), which are the ones that most frequently affect the coasts of B.C.S.

Therefore, in this project we use methodologies based on the analysis of nucleic acid transcripts to know the genes whose expression is affected (increased or decreased), and as a consequence identify the possible metabolic routes involved in the mollusk’s response.