A FISH KILL OF MASSIVE PROPORTION IN KUWAIT BAY, ARABIAN GULF, 2001: THE ROLES OF BACTERIAL DISEASE, HARMFUL ALGAE, AND EUTROPHICATION

Authors: GLIBERT, PATRICIA - UNIV.OF MD.ENVIRONMENTAL; LANDSBERG, JAN - FLA.MARINE RES. INST.; Evans, Joyce; AL-SARAWI, MOHAMMAD - ENVIRONMENT PUBLIC AUTH.; FARAJ, MUNA - ENVIRONMENT PUBLIC AUTH.; HAYWOOD, ALLISON - FLA.MARINE RES.INST.; IBRAHEM, SHAHNAZ - ENVIRONMENT PUBLIC AUTH.; Klesius, Phillip; POWELL, CHRISTINE - MARINE BIOTOXINS PROGRAM; Shoemaker, Craig

Submitted to: Trade Journal Publication
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/28/2002
Publication Date: 6/1/2002
Citation: GLIBERT, P.M., LANDSBERG, J.H., EVANS, J.J., AL-SARAWI, M.A., FARAJ, M., HAYWOOD, A., IBRAHEM, S., KLESIUS, P.H., POWELL, C., SHOEMAKER, C.A. A FISH KILL OF MASSIVE PROPORTION IN KUWAIT BAY, ARABIAN GULF, 2001: THE ROLES OF BACTERIAL DISEASE, HARMFUL ALGAE, AND EUTROPHICATION. HARMFUL ALGAE. 1 (2002) 215-231.

Interpretive Summary: A massive disease event was experienced in semi-enclosed embayment of the Arabian Gulf in 2001 involving nearly 300 tons of wild mullet. A smaller disease event involving sea bream being cultured in net pens was also experienced in the same embayment that had preceded the disease event in the mullet. The causative disease agent was determined to be Streptococcus agalactiae in both disease events. In addition, harmful algal blooms were observed that as the mullet kill progressed. Gymnodinium catenatum, G. impudicum, and Pyrodinium bahamese were the species of harmful algae observed. All the fish tested were below the limits of detection for paralytic shellfish poisoning and brevetoxins. The investigation concluded that many factor contributed to S. agalactiae disease events including usually warm water and calm conditions. This the first report of S. agalactiae being involved in high fatal disease of sea bream and mullet.

Technical Abstract: In August and September, 2001, Kuwait Bay, a semi-enclosed embayment of the Arabian Gulf, experienced a massive disease event that killed nearly 3000 tons of wild mullet (Liza klunzingeri Day 1888), due to the bacterium Streptococcus agalactiae. In the Bay, this event was preceded by a small fish kill (100-1000 dead fish d-1) of gilthead sea bream (Sparus auratus L.) in aquaculture net pens associated with a bloom of the dinoflagellate Ceratium furca. Sea bream were found to be culture positive for Streptococcus agalactiae, but did not show any visible signs of disease. Unusually warm temperatures (up to 35 deg C) and calm conditions prevailed during this period. As the wild fish kill progressed, various harmful algae were observed, including Gymnodinium catenatum, Gyrodinium impudicum, and Pyrodinium bahamese var. Compressum. Cell numbers of Gymnodinium catenatum and Gyrodinium impudicum exceeded 106 L-1 in some locations. All fish tested below the limits of detection for paralytic shellfish poisoning (PSP) and brevetoxins. Clams were found to be positive for PSP but at levels below regulatory limits. Nutrient concentrations, both inorganic and organic, were found to be highly variable with time and from site to site, reflecting inputs from sewage outfalls, the aquaculture operations, a high biomass of decomposing fish, and other sources. It is hypothesized that many factors contributed to the initial outbreak of the bacterial disease, including unusual warm and calm conditions. The same factors, as well as enriched nutrient conditions were also conducive to the subsequent HAB outbreaks. The detection of PSP, while below regulatory limits, warrants further monitoring to protect human health.