Fish Kills

By John Leaman   

Periodic events cause major reductions in fish population of the Indian River Lagoon.  Water conditions like changes in salinity, as caused by a major discharge from Lake Okeechobee or chemical issues such as fertilizer run off, cause an unhealthy situation and may result in sick fish and a gradual attrition, but it is not an immediate catastrophic event.   Also "red tide" occurs occasionally and causes some fish and invertebrate kills. This also causes temporary warnings to cease consumption for food purposes, but it too is not as catastrophic as a freeze or several consecutive days of near freezing temperatures.  On Christmas eve 1989 there was a very real freeze that killed not only thousands of fish, but also many palm trees and great areas of the mangroves that serve as the spawning grounds for many varieties of fish.  It took years for the Lagoon to recover from the freeze and you can still see dead remnants of some of the mangrove kills.  In 2010 there were several consecutive days of near freezing temperatures that resulted in a major fish kill as illustrated in the insert below.  Mullet and snook, including some huge ones, were the most affected and they covered the top of the water for hundreds of yards.  The floating mess moved around carrying the decaying fish odor with it.  It took several weeks for the odorous mess to disappear and it takes years for the population to rebound.

 Photo by  Myrtis Massatt