Spoil Islands Near Sebastian — Sebastian, Florida

The small wooded islands scattered along the Indian River Lagoon off Sebastian are not natural. According to the Florida Department of Environmental Protection (FDEP), spoil islands were created from dredge material during the construction of the Intracoastal Waterway, and the deposited material consists of sand, shell, muck and limestone rubble. They line the channel through the Indian River-Malabar to Vero Beach Aquatic Preserve, the state-protected stretch of lagoon that runs past Sebastian, Roseland and Wabasso.

Although FDEP describes spoil islands as not a natural community, the agency says they have become an important biological and recreational component of the Indian River Lagoon and have evolved into ecological communities that contribute to its biodiversity. The most striking measure is birds: FDEP states that spoil islands support the majority of bird rookeries in the Indian River Lagoon Aquatic Preserve system, which includes the waters off Sebastian.

The most specific public count for the Sebastian stretch comes from the state's 1986 management plan for the Indian River-Malabar to Vero Beach Aquatic Preserve. That plan notes that the Intracoastal Waterway extends the entire length of the preserve and counts approximately 55 spoil islands within it, while also noting islands that have eroded to shoals. The same plan describes Sebastian Inlet as the only opening to the ocean in this area and records salinities of 30 to 36 parts per thousand at Sebastian, compared with 20 to 26 near Malabar, a gradient that shapes which plants and animals settle on and around the islands.

FDEP today gives the preserve's size as 28,000 acres in Brevard and Indian River counties. The preserve was designated by the state Board of Trustees in 1970, included in the Aquatic Preserves Act of 1975 and designated as Outstanding Florida Waters in 1979. Some of the islands near Sebastian fall inside federal land as well: the U.S. Fish and Wildlife Service notes the many spoil and mangrove islands within the boundaries of Pelican Island National Wildlife Refuge, the refuge created in 1903 in the lagoon off Sebastian.

The islands are a mix of introduced and native habitat. FDEP reports that much of the vegetation on the spoil islands is exotic, consisting primarily of Brazilian pepper and Australian pine, while the shallow edges have been colonized by mangrove forest, salt marsh and seagrass beds. In the Malabar to Vero Beach preserve, which includes the waters off Sebastian, FDEP lists wading birds, seabirds and shorebirds, Atlantic bottlenose dolphin, West Indian manatee, green and loggerhead sea turtles, and fish such as redfish, black drum, tarpon, snook and mullet among the species of the preserve.

Bird nesting is the reason the islands receive special management. The 1986 state plan for the Sebastian area preserve set an objective to manage state-owned spoil islands within the aquatic preserve as bird rookeries and wildlife habitat areas. FDEP lists protecting bird nesting areas, planting mangroves, oyster reef restoration and seagrass surveys among current conservation efforts in the preserve, along with ongoing shorebird and seabird nesting research. Pelican Island National Wildlife Refuge, which holds many of the islands near Sebastian, provides feeding, nesting and roosting areas for over 130 species of birds, according to the Service.

Responsibility is shared. The Florida Inland Navigation District (FIND) maintains the Intracoastal Waterway that created the islands, and its dredging and land management program states that FIND started a long-term dredged material management program in 1986 to establish permanent facilities for material dredged from the 398 miles of the Intracoastal Waterway, which passes Sebastian on its way from Nassau County to Miami-Dade County. FIND also runs a Small-Scale Spoil Island Restoration and Enhancement program to promote the adoption and stewardship of spoil islands. Awards are capped at $20,000 per project and no more than $60,000 per county per fiscal year, and are open to government agencies, including Indian River County and its municipalities, that own a spoil island or hold at least a five-year lease or management agreement.

Restoration has a long local record. The NOAA Restoration Center lists the Spoil Island BC 48 Habitat Restoration in the lagoon off Grant-Valkaria in Brevard County, north of Sebastian, begun in July 2001 with the Sebastian Inlet Sportfishing Association as partner. The project removed invasive exotic plants that had colonized the island and created and restored two acres of mangrove habitat along with seven acres of surrounding upland habitat, adding an interpretive trail about the Indian River Lagoon.

Volunteer work continues. Sebastian Daily reported that on March 11, 2026, more than 20 volunteers restored three spoil islands in the Indian River Lagoon during the Environmental Learning Center's Spoil the Lagoon event, organized with Friends of the Spoil Island and FDEP's regional aquatic preserves office. Volunteers cleared overgrown trails, installed barbecue grills and logged 190 iNaturalist observations representing 37 species.

The islands are reached only by water. FDEP lists boat ramps and launches serving the Malabar to Vero Beach preserve, including the Main Street Boat Ramp in Sebastian, Sebastian Inlet State Park, the Wabasso Causeway Boat Ramp, MacWilliams Park, Christenson's Landing, Dale Wimbrow Park and Jorgenson's Landing. FDEP says spoil islands provide recreational opportunities for boaters through the lagoon and points visitors to the Friends of the Spoil Islands for visiting and camping information.

The water around the islands carries its own rules. FDEP states that seagrass is protected within aquatic preserves, advises boaters near Sebastian to avoid shallow water and raise motors over seagrass, and notes that damage to seagrass can result in a fine of up to $1,000. FDEP names fall and spring as the best times to visit the preserve, and lists beach and spoil island cleanups among its volunteer opportunities.