| 19 October 2010
Native plants give the food and shelter that fish have adapted to over millennia. photo: Dr. Phil Stevens
We all have a stake in shoreline
A concrete seawall does not support the food and shelter that Florida fisheries need for survival. Native plant communities, such as mangroves, seagrass and algae, give the food and shelter that native fish and fisheries have adapted to over the millennia. Productive fisheries need productive plant communities.
I have watched Florida seawalls, seagrass and mangroves for over five decades now. Sure you can see oysters settling on seawalls and little gobies and blennies settling in seawall oysters. Gray (mangrove) snapper juveniles will then settle in these oysters if the oysters are large enough, and eat the little crustaceans and fish that use seawall oysters.
But that cannot come close to the fishery productivity and biodiversity of a mangrove forest or seagrass meadow that feed the entire estuarine ecosystem, whether it is Tampa Bay or the Indian River Lagoon.
Mangroves and seagrass benefit both fish and people photo: Dr. Phil StevensMullet, menhaden and anchovies, the grazing cows of Florida estuaries benefit directly from the fungal, bacterial and algal communities that are supported by mangrove and seagrass communities. All our major fishery species depend on these three major fish grazers for food. This includes snook, tarpon and spotted seatrout as well as numerous other fishery species.
In 2004 and 2005 the South Florida Water Management District supported a survey of juvenile snook settlement habitat along the north Fork of the Loxahatchee River. Years of study had demonstrated that juvenile snook first settle into shallow nearshore waters that allow access to early food sources such as mosquitofish, and give some measure of escape from predators in deeper water. Unfortunately, there was very little of this habitat downstream where development had installed seawalls and docks. However, where there were natural sandbars and protected vegetated margins, there were snook, in some cases in large numbers. Fortunately most of this habitat was in the protected waters of Jonathan Dickensen State Park. The Park appears to be supporting most of the juvenile snook in the Loxahatchee River. Similar protected streams and mangrove forests throughout Florida are the sites that keep our snook and tarpon fisheries viable.
Armored coastline will not support abundant marine life. photo: Dr. Phil Stevens So how many miles of Florida estuaries have been converted into seawalls? I am sure someone in the State has that figure, but you know it is a large number. What can a fisherman do to enhance Florida fisheries if he happens to live on the water and has a seawall? Let plants grow in front of the seawall, even if they are bonsai mangroves. Even trimmed mangroves are better than concrete in producing organic food and shelter for estuarine shrimp, crabs and fish.
There are thoughtful and progressive people that have already done this and I applaud their efforts. Now it is time for everyone else with seawalls to get into the act and increase fishery production in Florida. If everyone did this increase in fishery production would far outweigh all the hatcheries in the State and it would not cost us anything!
Read More about...
The Role of Rivers in Snook Recovery
The Characteristics of Juvenile Fish Habitat
