Ichthyotoxin

This dinoflagellate, apparently widely distributed in temperate coastal waters, produces ichthyotoxins that have killed net-pen farmed salmonids in Norway, Scotland, and Ireland (Smayda 2006).

While such a pretreatment increased the sensitivity ten to forty times, the damage to the gills induced by brief exposure to ichthyotoxin was reversible.

The rate of the ichthyotoxic effect on immersed minnows within the temperature range of 10–30°C increases directly with the temperature (from 3 hours to 30 minutes), but the final titer of the ichthyotoxin is identical at both high and low temperatures.

More recently, Ehrhardt (1971) drew attention to ichthyotoxins as a whole. Among fish alone there are more than 500 species that are dangerous to man.

Ichthyotoxins are sufficiently widely present in the reef fish of tropical oceans, and with a sufficiently unpredictable occurrence, as to render the large-scale commercialization of snappers, groupers, jack, and other large, marketable fish a chancy business; in some iland groups, such as (it is claimed) Johnston and Phenix, very high percentages of species are toxic.

Ciguatoxin (CTX) is the principal ichthyotoxin involved in a complex human food poisoning known as ciguatera, characterized mainly by neurological, gastrointestinal, and, in the most severe cases, cardiovascular disorders (6—10).