Review of Harmful Algal Blooms (HABs) Causing Marine Fish Kills: Toxicity and Mitigation

Extensive growth of microscopic algae and cyanobacteria results in harmful algal blooms (HABs) in marine, brackish, and freshwater environments. HABs can harm humans and animals through their toxicity or by producing ecological conditions such as oxygen depletion, which can kill fish and other economically or ecologically important organisms. This review summarizes the reports on various HABs that are able to bring about marine fish kills. The predominant HABs, their toxins, and their effects on fishes spread across various parts of the globe are discussed. The mechanism of HAB-driven fish kills is discussed based on the available reports, and existing mitigation methods are presented. Lapses in the large-scale implementation of mitigation methods demonstrated under laboratory conditions are projected. Clay-related technologies and nano-sorption-based nanotechnologies, although proven to make significant contributions, have not been put to use in real-world conditions. The gaps in the technology transfer of the accomplished mitigation prototypes are highlighted. Further uses of remote sensing and machine learning state-of-the-art techniques for the detection and identification of HABs are recommended.

Automated summary

This review summarizes reports on harmful algal blooms (HABs) that result in fish kills in various parts of the world. It discusses the main HABs, their toxins, and their effects on fish. The mechanism of HAB-driven fish kills and existing mitigation methods are discussed. The review highlights gaps in technology transfer and recommends the use of remote sensing and machine learning techniques for HAB detection and identification.