Scientists Confirm Toxicity of Dinophysis Bloom in Corpus Christi Bay
Volunteers of the Phytoplankton Monitoring Network, working in conjunction with Texas Parks and Wildlife, recently discovered a developing bloom of toxic algal species. Both groups have been monitoring the bloom abundance for the past two weeks along Corpus Christi Bay, Texas. Samples sent to the NCCOS Analytical Response Team were identified as Dinophysis ovum, the same species that caused two previous blooms in 2008 and 2010.
Texas has a $30-million oyster season. This most recent bloom has cost the oyster industry approximately $7.5 million from September 2011 to January 2012. Fish kills have also accompanied this bloom, with over 4.4 million fish killed since November 2011. About half of these fish were striped mullet. Striped mullet are commercially important because they are used as bait fish.
Harmful algal blooms are a threat to the commercial and recreational harvesting of oysters. Identification and monitoring of these events are vital to maintaining the integrity of the $217 million-a-year commercial fishing industry in Texas. Liquid-chromatography mass spectrometry positively identified okadaic acid, a primary toxin responsible for human diarrhetic shellfish poisoning. Poisoning occurs by consuming contaminated shellfish like oysters.
In September 2011, all Texas shellfish beds were closed due to an unprecedented bloom of another toxic species, Karenia brevis. This led to devastating economic losses to the oyster fishery. Beginning in February 2012, some sites have been re-opened after shellfish were declared safe for consumption. However, the discovery of this toxic Dinophysis bloom in the harvesting region may again delay reopening of oyster beds in this critical Texas fishery.