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Over the past decade diatom blooms of domoic acid (DA)-producing Pseudo-nitzschia spp. have been responsible for numerous marine mammal and bird mortalities in Monterey Bay, CA. One possible toxin vector is the market squid, Loligo opalescens , a small pelagic mollusk that plays an important role in the near-shore food web of the California Current ecosystem as a favored vertebrate prey species. This study examined the trophic link between toxic Pseudo-nitzschia and L. opalescens using toxin and stomach content analyses of animals collected from Monterey Bay, CA in 2000. Receptor binding assay data (confirmed by tandem mass spectrometry), demonstrated the presence of DA in squid during a toxic Pseudo-nitzschia event, with P. australis frustules observed in stomach samples. Though DA levels were low ( −1 tissue) in L. opalescens during the study period, it is now clear that this potent neurotoxin can occur in squid and is likely delivered through its krill prey species, which are known to retain DA after feeding on toxic Pseudo-nitzschia . Our findings suggest that further study of the relationship between Pseudo-nitzschia blooms and DA contamination of squid is warranted to better evaluate the potential health risk to humans and wildlife associated with this major commercial seafood species and important prey item.

In August and September 2001, Kuwait Bay, a semi-enclosed embayment of the Arabian Gulf, experienced a massive fish kill involving over >2500 metric tons of wild mullet ( Liza klunzingeri ), due to the bacterium Streptococcus agalactiae . In the Bay, this event was preceded by a small fish kill (100–1000 dead fish per day) of gilthead sea bream ( Sparus auratus ) in aquaculture net pens associated with a bloom of the dinoflagellate Ceratium furca . Sea bream were found to be culture positive for S. agalactiae , but did not show any visible signs of disease. Unusually warm temperatures (up to 35 °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 bahamense var. compressum . Cell numbers of G. catenatum and G. impudicum exceeded 10 6 l −1 in some locations. All fish tested below the limits of detection for paralytic shellfish poisoning (PSP) and brevetoxins. Clams ( Circe callipyga ) were positive for PSP but at levels below regulatory limits. Nutrient concentrations, both inorganic and organic, were 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, also apparently were conducive to the subsequent HAB outbreaks. The detection of PSP, while below regulatory limits, warrants further monitoring to protect human health.