Modeled transport of winter flounder larvae spawned in coastal waters of the Gulf of Maine

Abstract

Winter flounder, Pseudopleuronectes americanus, from southern New England and the Gulf of Maine were historically considered to be obligate estuarine spawners. However, recent experiments and observations document that winter flounder in the Gulf of Maine also utilize coastal waters for spawning. An individual‐based modeling approach was used to investigate the transport of winter flounder larvae from three hypothesized coastal spawning grounds in the Gulf of Maine. Transport success rates were greatest for larvae released from Ipswich Bay, intermediate for Stellwagen Bank and least successful for those released from Jeffreys Ledge. There was substantial interannual variability in larval transport and geographic patterns of potential connectivity. Furthermore, the date of spawning had an important influence on transport success. Model results suggest that certain coastal spawning grounds used by winter flounder may serve as an important source of larvae to estuaries and nearshore nursery areas. The potential influx of coastal spawned larvae could have implications for the resilience, productivity and gene flow in local populations. Model results provide further support for the conclusion that winter flounder in the Gulf of Maine may not be solely dependent upon estuaries for spawning. Results also suggest that coastal spawning groups should be considered explicitly in the management of winter flounder, and protected under Essential Fish Habitat regulations.

Wind‐Modulated Western Maine Coastal Current and Its Connectivity With the Eastern Maine Coastal Current

“…The offline Lagrangian particle tracking was conducted using the Finite Volume Coastal Ocean Model (FVCOM) I‐State Configuration Model (FISCM) codes written originally to complement FVCOM model (https://github.com/GeoffCowles/fiscm; Decelles et al., 2015; Liu et al., 2015). Outputs from the NESS model were translated to FVCOM output format, which then drove FISCM to carry out the simulations.…”

Indications of Offshore Spawning by Southern Gulf of Maine Winter Flounder

“…Based on advances in tagging technology, divergent movement patterns of Winter Flounder populations during the spawning season are apparent, with some GOM Winter Flounder populations clearly neither estuarine dependent nor necessarily coastally dependent for spawning (DeCelles and Cadrin 2010;Fairchild et al 2013). Furthermore, although highly variable depending on the year and hatching date, modeling of Winter Flounder larval drift over a 5-year period, with early, mid-, and late-spawning groups, showed that Winter Flounder spawned and hatched from Stellwagen Bank, southern Jeffreys Ledge, and Ipswich Bay would contribute to estuarine juvenile populations (DeCelles et al 2015). Unlike the conventional belief that Winter Flounder larvae found within 25 km of shore are a result of outflowing from natal estuaries (Smith et al 1975), the inverse may be more apt for southern GOM Winter Flounder populations; these larvae originate from offshore spawning grounds, and a proportion of the larvae is advected into estuaries.…”

Northern quahog (Mercenaria mercenaria) larval transport and settlement modeled for a temperate estuary

“…Previous larval transport models for marine taxa have used various cues to indicate successful benthic settlement, including substrate type (North et al ; Liu et al ), depth (Decelles et al ), and spawning zones or stock biomass (Liu et al ; Munroe et al ). In laboratory settings, quahog have been found to prefer sand over mud as a settlement substrate (Keck et al ); however, quahogs have also been known as having a gregarious settlement behavior (Keck et al ), with settlement occurring in mud, sand, a mud‐sand mix, gravel, sand with rocks and shells, silt‐clay substrate, and eelgrass beds (Pratt ; Pratt et al ; Rice ) Larval settlement preferences have been attributed to several factors, including representing areas with lower predators (Bricelj ), absence of organic matter and its associated bacteria, and presence of quahog pheromones (Keck et al ).…”