Friday, June 10, 2016

Building an Artificial Oyster (Castle) Reef - part II

Several VLM staff members from three departments recently headed to Chincoteague over two day-long sessions in May to help the Nature Conservancy construct artificial oyster reefs out of concrete "castles". Staff and volunteers met at Chincoteague wild and beautiful USFWS National Wildlife Refuge on Virginia's Eastern Shore. The area is best known for its wild ponies that roam free amid the dunes and low grasslands adjacent to the Atlantic Coast. The shallow inlets within the refuge experience heavy tidal flow that provide rich waters and ideal conditions for oyster reefs.


Just a few of the many wild ponies that inhabit the island

These reefs are constructed of tiered concrete blocks that are designed to be stacked and interlocked vertically into a pyramid-like structure (see below). When these stacked blocks are oriented in a staggered horizontal line, they create a reef that acts as a breakwater to diffuse wave energy, trap sediment also allows plenty of hard surface for oyster spat to settle on preventing their possible burial.

 Before and after: First "castles" are left in piles in the inlet, then rearranged by volunteers into specific patterns, as well as long rows, for both stability and maximum oyster growth. 

A model of the castle configuration on dry land

Actually building the reef

 The "castles" had to be towed around when the water was high.

According to biotic surveys done on the reefs constructed last year with the assistance of the VLM aquarium staff, the reefs were deemed to be very successful and highly colonized, meaning lots of new oyster, fish, crabs and other inverts now call that reef home!

A clump of healthy oysters with plentiful algae

Fishes like this striped burrfish come to oyster reefs to feed on inverts

We have a live display of an artificial oyster reef on-site that exhibits live animals that inhabit healthy oyster reefs and provides information on the work being done by the Nature Conservancy and Christopher Newport University Professor Dr. Russ Burke. The efforts to provide a healthy habitat for wild oysters and the ever-growing oyster cultivation industry are helping to spur a slow but steady comeback by one of the Bay's iconic animals the American oyster. 






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