The delicate balance of native marine communities is at risk. Invasive aquatic species are among the deadliest threats to the waters and coral reefs of Hawaii with the potential to impact public health, as well as the state's economy and the environment.

Dinoflagellates are a group of microorganisms that are best known for their toxicity and role in harmful algal blooms (HABs). HABs, known also as red tides, cause massive fish kills. Direct effects on human health include severe allergic reactions, skin blisters and abscises, and human consumption of fish and shellfish contaminated by toxic and harmful dinoflagellates can cause illness (ciguatera) and in severe cases, death. Although HABs have never been reported for Hawaii, there is the possibility that toxic and harmful dinoflagellates are entering Hawaii in the ballast water of commercial ships.

Dinoflagellates are a normal part of the marine environment and the majority of them are harmless. Almost nothing is known about natural dinoflagellate populations and other such microorganisms in Hawaii. A HISC-funded collaborative research project between HIMB and DAR scientists aims to describe the existing dinoflagellate communities and evaluate current regulations in restricting their transport and introduction in ballast tanks associated with shipping activities. The goal is the early detection of harmful and toxic dinoflagellates introductions in Hawaiian waters.

 

Ruth Gates, researcher with the Hawaii Institute of Marine Biology (University of Hawaii) and, in collaboration with DAR, a recipient of a HISC Research and Technology grant.

Photo by HISC

 

Scientists are using a DNA bar-coding approach to characterize seawater samples collected in and around Honolulu Harbor and Johnston Atoll where there is heavy shipping and ballast water exchange activity. These are compared to samples collected at French Frigate Shoals and Kaneohe Bay where there is little shipping activity and no ballast water exchange.

 

In parallel, ballast water samples, made available through collaboration with Matson Navigation Company, are being analyzed for the presence of toxic and harmful dinoflagellates. Pre-exchange samples are taken at various ports where the ships traveling to Hawaii take on ballast water. Consistent with the newly implemented ballast water exchange laws, approximately 200 miles offshore of Hawaii, 95 percent of the ballast water is exchanged. When these ships come into port, a post-exchange ballast water sample is taken and analyzed.

 

The results show that dinoflagellates are still present in the post-exchange samples, suggesting that while 95 percent of ballast water discharge may control larger vertebrate and invertebrate invaders, the residual 5 percent may serve as a "point of entry" for invasive microorganisms, such as toxic dinoflagellates.