Tuesday, January 29, 2013

A Small Dose of Red Tide


 Many species of fish litter the beach due to red tide in Sarasota, FL

Walking back across the street from the beach, my eyes hurt so much that I could barely open my eyes.  I was at the beach maybe 20 minutes, but probably less.  Red tide was hitting the area and wind was stirring the water and blowing the neurotoxin towards the beach.   

A Silver Grunt among seaweed stranded on the dry beach.  

The last few days, I noticed floating dead fish in the waters.  Now, the beach is littered with multiple species of dead fish. Once home from the beach, I rinsed my eyes out with water, then sat on the ground and cried because it hurt so much.  Eventually I tracked down some eye drops so I could function once again. 

A pin fish dead on the beach due to red tide.

A large algae bloom causes red tide.  Under the right conditions, such as warm temperatures and coast upwelling, the algae multiply.  There are a variety of species that can cause algae blooms, but in these Florida waters, it is primarily caused by Karenia brevis, a type of dinoflagellate.  This is one example of a species that actually produce toxins. Luckily for humans the red tide organism, Kareneva brevis, is not deadly but it could cause respiratory distress and irritated eyes.

Spade Fish victim to red tide.

Red tide is a concern for many reasons.  The most obvious one is the killing of fish. Millions of fish have died due to this harmful algae bloom. Many species are affected and it’s sad to walk down the beach and see so much death.  It feels so ominous.   

Lane Snapper with its last gasp for oxygen frozen in time.

These fish deaths also affect those species that rely on them as a food source, such as dolphins.  In 2004, 107 dolphins died in Florida’s panhandle due to high levels of brevetoxins (the toxin found in Karenia brevis) from eating fish.  Manatees, birds and sea turtles can also die directly due to these toxins. 

Gafftopsail Catfish dead in the surf on Lido Key.

There is controversy around the cause of red tides. Some people believe that humans contribute to red tides so we harbor some blame.  Nitrogen and phosphorus, chemicals often found in fertilizers, can allow algae blooms to grown faster. According to NOAA, the occurrence of harmful algae blooms has been increasing. 

 A Cow Fish loses it's vibrant color after dying due to red tide.

This time, the red tide was short lived and the next day I could walk on the beach without coming home crying.  Other years the red tide has stayed around for months and killed countless animals and effected sea life populations.  It was interesting to see the effects, but I am glad it is now gone.

A Sand Seatrout is not very distinguishable about dying from red tide.

1 comment:

Anonymous said...

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