Restored Coastal Habitat Can “Reel In” Juvenile Sportfish: Population and Community Responses in the Indian River Lagoon, Florida, USA

Abstract

Coastal habitats are declining worldwide, which has impacted economically important fisheries, especially in the Indian River Lagoon, Florida. As a result, extensive intertidal oyster reef and living shoreline restoration projects have been implemented. Restoration can also theoretically benefit predator populations, but this relationship is understudied. Here, the impact of habitat restoration on juvenile predatory fish (i.e., sportfish) populations (abundance) and communities (species richness, diversity, and assemblage) was assessed prior to and following oyster reef restoration and living shoreline stabilization for up to three years, and incorporated the influence of 17 environmental predictor variables. Juvenile sportfish abundance and richness (n = 11) were variable over time but collectively higher on restored oyster reefs compared to controls, and similar between control and stabilized shorelines. Sportfish abundance was best described by a combination of biotic features of the site (e.g., reef height and benthic substrate cover), prey abundance, decreasing distance to the nearest ocean inlet and dissolved oxygen. Results suggest future restoration site selection should emphasize adequate dissolved oxygen (~6 mg/L), oyster densities above 50/m2 and reef height above 55 mm, and minimum shoreline vegetation coverage of 50% to support macrofaunal prey and subsequently attract sportfish. These findings can help natural resource managers better use habitat restoration as a tool for enhancing fish populations in the future.

Impact of Oyster (Crassostrea virginica) Reef Restoration on Benthic Invertebrates and Coastal Birds in a Subtropical Estuary

“…Lenihan et al [58] found that piscivorous fish abundances around restored reefs were similar to those around natural reefs in a North Carolina estuary. In Mosquito Lagoon, Loch et al [59] also found an increase in juvenile sport fish around restored reefs. The ability of these restored reefs to support higher trophic-level organisms such as piscivorous fish and birds indicates success in restoring the trophic structure on these reefs.…”

Evidence of ontogenetic partitioning of restored coastal habitat by a generalist sportfish

“…bulkheads and riprap) using a seaward breakwater consisting of stacked oyster shell bags to attenuate wave energy, and shoreward planted vegetation (i.e. cordgrass Spartina alterniflora and mangrove Rhizophora mangle ) to reduce shoreline erosion (see Donnelly et al 2017; Loch et al 2021). Three stabilized shorelines were compared to two control (i.e.…”

“…1). Oyster density, reef height, and shoreline vegetation percent cover data were collected (Donnelly et al 2017;Loch et al 2021; Walters et al 2021). Sportfish were captured using a bag seine (21.3 × 1.8 m; 3.175 mm mesh) pulled parallel to the site prior to and following restoration at 1, 2, 4, 6, 8 and every 12 weeks thereafter for up to 3 years.…”

“…However, coastal habitat modification has resulted in declines in fish diversity, abundance, biomass, and fisheries landings (Gilby et al 2018; Freeman et al 2019). Thus, restoration of benthic habitats in coastal and estuarine systems can be used to recover the abundance and diversity of macrofauna (Rezek et al 2017; Searles et al 2022), and resident and transient fishes (Lewis et al 2021; Loch et al 2021; Mahoney et al 2021; Troast et al 2022). More specifically, restored oyster reefs and living shorelines have the ability to increase the biomass and production of mobile fish and crustaceans (Peterson et al 2003; Gittman et al 2016; zu Ermgassen et al 2016; McCoy et al 2017; Isdell et al 2021).…”

“…More specifically, restored oyster reefs and living shorelines have the ability to increase the biomass and production of mobile fish and crustaceans (Peterson et al 2003; Gittman et al 2016; zu Ermgassen et al 2016; McCoy et al 2017; Isdell et al 2021). This translates to greater commercial fisheries value (Grabowski et al 2012), notably to sportfish, defined here as higher trophic level fishes targeted by anglers (Humphries & La Peyre 2015; Loch et al 2021).…”