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Aquatic Preserves

Nassau River-St. Johns River Marshes Aquatic Preserve

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Located on the northeastern coast of Florida, the aquatic preserve lies along the Atlantic intracoastal waters of the St. Marys, St. Johns and Nassau rivers. The preserve is situated between the cities of Fernandina Beach and Jacksonville.

History

The Nassau River-St. Johns River Marshes Aquatic Preserve was officially designated on Nov. 24, 1969. The primary goal of its establishment was the protection of the vital estuarine resources found within the Nassau Sound area's marshes and associated waters. This area was recognized as a "biological" preserve due to its ecological significance. The establishment of the preserve aimed to safeguard the region's delicate ecosystem against the threats of urban, residential and industrial development.

Scientific Information

The coastal region of Northeast Florida, where the Nassau River-St. Johns River Marshes Aquatic Preserve is located, boasts over 100 documented archaeological and historical sites. This abundance of cultural remnants underscores the attractiveness of this area to its past inhabitants, who were drawn to its fertile marshes, bountiful offshore waters and numerous inlets and natural harbors. The earliest traces of human presence in the region date back to approximately 3500 BC. These early inhabitants, identified as the Timucuan Indians, thrived in the coastal areas between the mouth of the St. Marys River and the region below St. Augustine. The Timucuan people sustained themselves through a blend of horticulture, shellfish gathering and hunting and gathering activities. Archaeological excavations of midden deposits have revealed that mullet, sheepshead, black drum and catfish constituted their primary fish diet, while oysters, clams, mussels and whelks served as essential shellfish resources.

The geological formations within the Nassau River-St. Johns River Marshes Aquatic Preserve, encompassing barrier islands, marshes, channels and tributaries, are classified as the southernmost extension of the St. Marys Meander Plain. This coastal expanse, stretching from the St. Johns River to the Santee River in South Carolina, is known as the “Sea Islands” due to its distinctive chain of barrier islands. These islands, separated from the mainland by meandering tidal creeks, are the product of alluvial and tidal sedimentation within ancient lagoons. The salt marshes within the preserve, formed through the continuous accumulation of sediment, are steadily increasing in elevation. However, this upward growth is counterbalanced by the ongoing rise in sea levels.

The Nassau River-St. Johns River Marshes Aquatic Preserve boasts a rich and dynamic ecosystem dominated by expansive salt marshes. These marshes serve as vital nurseries for a diverse array of fish and wildlife species. Frequent tidal flushing contributes to high primary plant production, ensuring a continuous flow of nutrients within the estuary. The preserve also features numerous tidal creeks, essential feeding grounds for commercially valuable fish species. The interplay of salt marshes, tidal flats and beaches creates a complex and interconnected web of life, supporting a thriving ecosystem.

Wildlife Habitat and Ecosystem Types
Aquatic preserve 

Nesting and Migrating Birds
Clapper rails, willets, red-winged blackbirds, seaside sparrows, marsh wrens, herons, egrets, ibis, wood storks

Mammals
Raccoon, marsh rabbit, opossum, bobcat, river otter, white tailed deer, rice rat, cotton mouse, bottlenose dolphin, manatee

Reptiles
Loggerhead sea turtle, green sea turtle, diamondback terrapin, American alligator 

Fish
Ladyfish, Atlantic menhaden, spot, mummichog, silverside, striped mullet, spadefish, pinfish, spotted sea trout, red drum, weakfish, croaker, northern kingfish, jack crevalle, lookdown, Florida pompano, pigfish, grunt, threadfin herring, southern flounder, summer flounder, bluefish, butterfish, mojarra, sheepshead

Conservation Efforts

The core conservation objective for the Nassau River-St. Johns River Marshes Aquatic Preserve is to safeguard its essentially natural condition for the benefit of future generations. This involves minimizing water pollution and the loss of wetlands, particularly in light of the increasing urban, residential and industrial development in the surrounding region. Key conservation efforts focus on:

  • Maintaining the health of salt marshes: Salt marshes are crucial for estuarine productivity, providing essential habitat for fish and wildlife. Conservation efforts aim to protect these areas from development and pollution.
  • Managing water quality: Protecting the high water quality of the estuary and ensuring the natural seasonal flow fluctuations of freshwater into the system are critical for the health of the ecosystem.
  • Protecting threatened and endangered species: The preserve provides habitat for a variety of rare and endangered species and conservation efforts prioritize the protection and enhancement of their habitats.

Ongoing Research

The management program will rely on research conducted by various entities, including government agencies, colleges, universities, scientific foundations and private consultants. The insights gained from this research will inform management decisions and ensure the long-term health of the preserve's ecosystem. One notable research effort mentioned is a study by the Department of Natural Resources' Marine Lab that focuses on fishery habitat losses in the Tri-River System. This research will contribute valuable data to the development and implementation of the preserve's management plan.

Frequently Asked Questions

While the aquatic preserve offers year-round recreational opportunities, if guests are wanting to get into the water, April through October offers average water temperatures above 70 degrees. November through March provides excellent fishing opportunities from shore or boat as well as beach combing and bird-watching on much less crowded beaches than the warmer months. 

For a comprehensive understanding of available educational activities, explore the websites of the surrounding parks and relevant organizations.

Yes. Aquatic preserves often are adjacent to other conservation areas that may have nesting birds or other easily disturbed wildlife. Please do not let your pet run free in areas not designated for pets, and please pick up after your pet to avoid hazardous pathogens in our coastal waters. 

Follow current FWC saltwater fishing regulations.

Follow current FWC boating regulations.

Seagrass is protected within aquatic preserves; avoid shallow waters and raise motor if over seagrass. Damage to seagrass can result in a fine up to $1,000. 

Call Florida Fish and Wildlife Conservation Commission at 1-888-404-FWCC (3922).

ADA accommodations are specific to each access point and the managing entity for that site. 

Donations toward public efforts that qualify through Florida Department of Environmental Protection's standards of ethics are accepted.

Contact the office staff and request a volunteer packet.

Partner Groups

  • U.S. Fish and Wildlife Service
  • U.S. Army Corps of Engineers
  • Florida Marine Patrol
  • Florida Fish and Wildlife Conservation Commission
  • Northeast Florida Regional Planning Council
  • Nassau and Duval counties
  • City of Fernandina Beach
  • City of Jacksonville