Abstract

In November 2007, a series of beaching events involving more than 500 marine birds of various species occurred within Monterey Bay over approximately 3 weeks. This event was variously blamed on the aerial spraying of a pheromone product for light brown apple moth (LBAM), on a spill of non-petroleum oil, and/or a massive red tide event that occurred in Monterey Bay during the same time period. Affected birds presented with wet feathers and were weak and hypothermic; some had a linseed oil-like smell. Scant, slimy pale yellow-green fluid could be wiped off the feathers of affected birds on presentation, but it dried out with time. The birds beached in three distinct pulses that corresponded temporally with the presence of a large dinoflagellate bloom just offshore. Upon washing, rehydration, warming, and nutritional supplementation, many affected birds recovered, suggesting that the product was minimally toxic or nontoxic. The event was ultimately traced to the dominant dinoflagellate in the red tide, Akashiwo sanguine. During breakdown and augmented by wave action, this organism elicited large quantities of a protein dimer of the same composition and molecular weight as protein recovered from feathers of affected birds, but was not present on unaffected birds. Further, surface foam and scum that was present on the water near the dinoflagellate blooms during this event, when spread on normal feathers, acted as an effective wetting agent. Dinoflagellate blooms have been previously linked to coral bleaching, due to the formation of a proteinaceous material similar to that found in the 2007 event. This is the first report of an ostensibly nontoxic, but harmful algal bloom (HAB) caused by a dinoflagellate surfactant protein impacting marine birds. Although the protein was relatively easy to clean off the birds using modified oil spill procedures, the event occurred just following seasonal migration of many species from the arctic. It affected about 10% of northern fulmars (Fulmarus glacialis) arriving in Monterey Bay, of which approximately half died. Significant mortality in surf scoters (Melanitta perspicillata) and Clark’s (Aechmophorus clarkii) and western grebe (Aechmophorus occidentalis) added to large numbers of these species killed by the concurrent Cosco Busan oil spill.