Potential southern flounder spawning locations identified with particle dispersal modeling

Historically, southern flounder (Paralichthys lethostigma) is one of North Carolina’s most valuable finfish fisheries. Despite this, the species is managed without knowledge of its spawning location making it difficult to determine an appropriate spatial scale for management. Southern flounder is regulated at the state level, despite evidence that a single genetic population exists from Virginia to Florida. In addition to current management challenges, southern flounder has experienced a long-term recruitment decline, which became more pronounced around 2007. Currently, little data exist for southern flounder spawning events. Here, potential spawning locations of southern flounder are identified using Lagrangian simulations that backtrack larval particles collected near Beaufort Inlet in North Carolina. Backtracking simulations are conducted using the Connectivity Modeling System (CMS) forced by ocean circulation fields generated by a global earth system reanalysis and then a ROMS model. Simulations reveal a large range of potential spawning locations exist for southern flounder. However, in all years analyzed and under both models, the highest probability of spawning occurred in southern Onslow Bay, NC. There is also evidence that some larvae may originate from other states, such as off the coasts of Georgia and Florida. This suggests that genetic homogeneity may result from infrequent, long-distance dispersal. These results provide useful insights on the primary spawning grounds of southern flounder, which can help to support better spawning stock biomass assessments.

Presentation Preference: Oral

Primary Presenter: Brian Bartlett, East Carolina University (bartlettbr24@ecu.edu)

Authors:

Brian Bartlett, East Carolina University  (bartlettbr24@ecu.edu)

Caitlin McGarigal, New Jersey Department of Environmental Protection  (caitlin.mcgarigal@gmail.com)

Victoria Garza, Lousiana State University  (vgarza6@lsu.edu)

Cheryl Harrison, Lousiana State University  (cherylharrison@lsu.edu)

Rebecca Asch, East Carolina University  (ASCHR16@ECU.EDU)