What is the best material to restore oyster reefs?

This project was supported by funding from the Tampa Bay Estuary Program to START. We were a collaborator with START (Solutions To Avoid Red Tide), Manatee County, and the Chiles Restaurant Group.

Oyster shells from local restaurants were collected and stockpiled for future oyster reef restoration projects. We (GSI) used some of these shells to answer two questions relevant to future restoration efforts.

The first objective was to compare fresh shell collected from local restaurants with fossil shell as substrate for attracting newly set oysters.

The second objective was to determine how oyster spatfall varied throughout the year.

Our approach was to suspend mesh bags of both types of shell in the intertical zone; replace the bags with clean shell each month for a year; and count the number of newly settled oysters on each shell.

This project was conducted between June 2017 and May 2018 at Robinson Preserve in Manatee County. Fresh shell attracted significantly more oyster spat than fossil shell. In addition, spatfall occurred from June through November, but most spatfall occurred in October 2017. No settlement occurred in January, February and March 2018. Settlement resumed in April and May 2018.

The conclusions are to use fresh shell for oyster restoration to the greatest extent possible and to place it into the water as close to October as possible.

The final report is available on our Publications page.