Plants and animals common to these areas must have the ability to exist in both salt and fresh water as the flow due to tides, along with fresh water runoff, creates a continuing change in salinity.

Incoming tides produce higher concentrations of salt while falling tides, along with drainage and runoff, result in lower salinity levels.  In addition, much of the estuary bottom can be exposed several times a day during low tide.

Obviously, there is a delicate balance from one cycle to another requiring very adaptable forms of marine life.  If this balance is lost due to interference by man and development, the certain result is death to the system.

A surprising fact is that over 70% of the fish, shellfish and crustaceans important to the commercial fishing industry spend some part of their life in an estuary.

Many of the species may have life cycles that flow from the shallows to far out in the ocean and then back again.  It’s unbelievable to think that small organisms such as the common shrimp exist in a range of such distance.

Not only do shrimp follow such life cycle movement, but so do many other species.  Tarpon, for which our area is so well known, makes a similar journey as small larvae.  The deep blue waters offshore of Boca Grande, as far as 100 miles or so, are considered to be one of the most prolific spawning areas in the world for tarpon.

Tarpon begin to gather at Boca Grande and nearby beaches during mid April for a period of time that usually lasts through late July or early August.  The spawning activity is the ultimate reason for the fish to be here, although reproduction does not take place immediately after they arrive.

Most experts think that tarpon gather at Boca Grande Pass several months prior to spawning due to the large and concentrated amounts of food that flows in and out on the tides.  This period of time gives females the opportunity to gain strength and weight for the ultimate spawning ritual that will result in her release of up to 15 million eggs while a dozen or so males take their turn in the fertilization process, which occurs far offshore.

During a period of about 45 days, the tarpon larvae, which start out microscopic in size, make their way back to the passes and across Charlotte Harbor to the shallows where they grow into juvenile fish.  The smallest larvae that have been collected measured ¼ inch in length and were taken far offshore with very fine mesh nets trolled at various depths.

By the time these larval tarpon reach inshore, they have grown to about 1-1/2” inches in length.  From that point to the time when they become small tarpon in the shape and form we know them, their existence is in the backcountry and estuarine shallows.  It’s amazing, but true…a trip of up to 100 miles or more by larvae no bigger than a very small shrimp which someday become mighty silverking weighing in excess of 100 pounds.

What’s more amazing is that the areas where small tarpon nurture can be void of clean oxygenated water and it takes very little, either fresh or salt, for the tarpon to survive and grow.  When necessary, they can breath from the surface using the airbag they contain from prehistoric times.

The tarpon is only one of many estuarine creatures that have amazing life cycles.  Obviously, estuaries must be protected from devastation, as they are very necessary.  Development, dredging, blocking highways, chemical runoff, etc. are the ultimate enemies.

With this in mind, any diversion of waters from natural river courses and coastal flows to areas of development by man is scary.  We all know that Florida needs help in the way of natural balances, but diverting waters for the sake of engineering consequences could very threatening to local backwaters and the many forms of sea life included.

Another concern from man’s intervention is the change in salinity levels at various tide stages.  Again, the life cycle balance of sea life growing up in these waters is very delicate.  Even a minor disruption to salinity levels can be disastrous to the very nurseries from which much our sea life prosper.

Hopefully, the change in shallow water areas and natural shoreline will be drastically reduced in the future so as to protect Florida’s natural backwater resource.  Meanwhile, it’s time to enjoy the beautiful shallow water resource we have along the southwest Florida coast and remember how important these estuarine waters are to saltwater marine life cycles that extend far offshore.