RED TIDE, FISH - USA: (TEXAS)
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Date: Mon 24 Oct 2011
Source: Corpus Christi Caller Times [edited] <http://www.caller.com/news/2011/oct/24/red-tide-outbreak-continues-to-kill-fish-cause/>
The most widespread bloom of toxic red algae to plague Texas in a decade continues to kill fish and cause respiratory irritation along Coastal Bend beaches and bayfronts.
Rust-colored water stretched from Matagorda Bay to South Padre Island on Monday [24 Oct 2011], according to Meridith Byrd, a harmful algae specialist with Texas Parks & Wildlife. Local reports include dead fish and discolored water in Corpus Christi Bay near Ingleside by the Bay, a fish kill at Goose Island State Park, and respiratory discomfort and stressed fish in San Antonio Bay. There also are reports of heavy aerosols along most Padre Island beaches with moderate deposits of dead fish along parts of Mustang Island from Port Aransas to just north of Packery Channel.
Biologists estimate this red tide outbreak has killed about 3 million fish. The previous outbreak in 2009, which was confined to an area from roughly Port Aransas to Mexico, killed an estimated 5.5 million fish.
Beachgoers in Port Aransas last weekend [22-23 Oct 2011] endured heavy aerosols, which cause itchy eyes, sore throats, and coughing, Byrd said. The effects remained in the air there Monday, but were not as strong. Dead fish along Mustang Island mostly were mullet, ladyfish, and menhaden. The heaviest concentration of dead fish littered the beach near the Fish Pass jetty.
Red algae thrive and multiply in warm salty seawater. Drought conditions create saltier bays by limiting freshwater flow from rivers and by not offsetting normal evaporation with rainfall. Generally, red tide blooms subside when coastal waters cool.
A cool front is expected to hit the Coastal Bend this week [week of 24 Oct 2011]. Byrd said the gulf and bay temperatures must drop to about 60 deg F [15.5 deg C] to reverse the outbreak. Bay temperatures were in the mid-70s [deg F/mid 20s deg C] Monday.
[Byline: David Sikes]
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[The opening to this article talks about red algae. While there is red algae, it is not what causes red tide. Red tide is much larger in scope and can be toxic.
Red tide is caused by several toxic algae. Depending upon the toxin, it is also known as paralytic shellfish poisoning (PSP), because it causes shellfish to be toxic for consumption.
_Alexandrium_ spp. is one of many members of this genus. Some members may not be toxic. However, generally, the genus is found in coastal waters high in nitrogen content. These organisms produce a neurotoxin, like many of the organisms capable of causing paralytic shellfish poisoning (PSP). The neurotoxin is considered fatal for humans consuming contaminated shellfish and may be dangerous to humans and animals who swim in waters that are 'blooming' with the organisms.
Ocean spray containing the organisms may also cause illnesses, including rashes and eye irritation in people. Some species of this genus are capable of causing 'red tide' that may be visible for long distances along a coast line.
PSP is a significant problem in several geographic areas, especially on both the east and west coasts of the US. Produced by several closely related species in the genus _Alexandrium_, PSP toxins are responsible for persistent problems due to their accumulation in filter-feeding shellfish, but they also move through the food chain, affecting zooplankton, fish larvae, adult fish, and even birds and marine mammals.
_Alexandrium_ blooms generally do not involve large-cell accumulations that discolor the water and may instead be invisible below the water surface. Low-density populations can cause severe problems due to the high potency of the toxins produced. Furthermore, _Alexandrium_ spp.
can grow in relatively pristine waters, and it is difficult to argue that anthropogenic nutrient inputs are stimulating the blooms. These characteristics are important when considering mitigation and control strategies.
Often PSP is associated with red tides or algal blooms. Red tide is caused by an organism called _Karenia brevis_, which in high concentration can make the water look red. The organism releases a toxin that paralyzes the respiratory system of fish and other marine life.
Airborne toxins, water spray, and splashes in an outbreak have kept people from beaches while leaving others with irritated eyes and throats. Red tide irritates the skin of people exposed to it and can cause itchy eyes, scratchy throats, and coughs. Harvesting from affected areas for personal consumption is discouraged. Red tide poisoning symptoms include nausea and dizziness and may last for several days.
Previously the organism causing red tide was known as _Gymnodinium breve_, but it has been reclassified in the taxonomy of dinoflagellates. Its new name is _Karenia brevis_, or _K. brevis_.
Karenia was chosen in honor of Dr Karen Steidinger, a prominent red tide scientist from the Florida Marine Research Institute in St Petersburg, Florida (<http://www.mote.org/index.php?src=gendocs&ref=%28renamed%29%20Red%20Tide%20Update_608&category=Ecotoxicology>).
- Mod.TG]
[see also:
Red tide, shellfish - USA: (MA) alert 20110506.1400 2010
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Paralytic shellfish poisoning - USA: (ME) warning 20100714.2353
2007
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Paralytic shellfish poisoning, human - USA (ME) 20070802.2508 Red tide, aquatic mammals - USA: (FL) 20071231.4199 Manatee deaths, red tide - USA (FL) 20070403.1129
2006
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Red tide, shellfish - USA (WA) 20060824.2388
2005
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Red tide - USA (TX) 20051002.2886
Red tide - USA (FL) (06) 20050925.2829
Red tide- USA (FL) (05): sea turtles 20050819.2437] .................................................sb/tg/mj/dk/ll
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