A brief overview on the life cycle of bonefish

1. Spawning.  Based on when and where very young larvae have been found, we believe spawning occurs during late spring and summer.  However, spawning locations are unknown.  On the Gulf coast of Florida, our best guess is that tarpon spawn from May through July, perhaps as far as 100 – 150 miles offshore. 
We believe that tarpon spawn in a similar manner to most marine fish, called broadcast spawning – males and females gather in groups, and eject their eggs and sperm into the open water, where fertilization occurs.  After a number of hours, the eggs hatch into small larvae. 

2.  Larval Phase.  All fish and fish larvae have otoliths (earbones) that help them with equilibrium and hearing.  The earbones also have rings on them – in larvae and juveniles, one ring for each day.  Based on counting the daily rings on tarpon larval otoliths, it has been determined that tarpon larvae live as plankton in the open ocean for between 14 and 26 days. 

Larval tarpon look EXACTLY like larval bonefish

3 and 4.  At the end of their larval stage, the tarpon larvae undergo a metamorphosis – they shrink and change shape, becoming miniature versions of their parents.  Juvenile tarpon live in shallow, backwater estuarine and freshwater wetland habitats, and slowly make their way toward deeper, more open water as they grow.

A juvenile tarpon, less than 1 year old

5. Larger juveniles (adolescents) and young adults.  These fish are most common in protected backwaters – estuarine or freshwater. 

A juvenile tarpon apprximately one year old

6.  Adults.  Probably because we fish for them, we know most about adults, but are still far from where we need to be in our knowledge base.  We have a general idea of their diets (but no comprehensive study has been done), and their habitats, but do not know the extent of their site fidelity (how long they stay in a small area), migrations (indications are they can move miles between flats), their growth rates (growth rates seem to vary among locations), or where they spawn.

All material copyright Aaron Adams 2007, 2008, and beyond, unless noted.