Common Snook Centropomus undecimalis in Coastal Alabama: Climate-Driven Expansion of a Tropical Sportfish in the Northern Gulf of Mexico

As global temperatures increase, organisms have responded by expanding their distributions poleward. Rising minimum air and sea surface temperatures contribute to overwinter survival of cold-sensitive species, allowing tropical species expansion into subtropical and temperate environments. Recently, Common Snook (Centropomus undecimalis, hereafter “Snook”), a highly prized and predatory sportfish, has been documented in increasing abundance in coastal Alabama (USA). Historically, Snook have been latitudinally restricted to water temperatures > 10–12℃, but recent documentation of Snook at higher latitudes in Florida, South Carolina, and Texas suggests poleward range expansion of the species. This study documents the novel year-round presence of Snook in coastal Alabama through various news reports, social media, and personal communications with fishers, managers, and stakeholders, including confirmed survival of Snook following a historic cold event in January 2025. Up to 147 Snook sightings were recorded in Alabama between 2012 and 2025, with the highest number recorded in 2024; 32 sightings occurred in autumn (Sept-Nov), 29 in winter (Dec-Feb), 35 in spring (Mar-May), and four in summer (Jun-Aug). A breakpoint analysis of air temperature data in Mobile, Alabama (USA) from 1980 to 2025 identified a shift around 2010, after which the number of days ≤ 12°C decreased relative to previous decades, suggesting milder winters that may facilitate Snook survival and establishment. Following state record-breaking Snook catches in two consecutive years (2023 and 2024), Alabama resource managers enacted catch restrictions and regulations in anticipation of a growing Snook population. Sightings documented in this study support the presence of an established resident Snook population in coastal Alabama. In response to emerging management needs and growing public interest, plans for ongoing and future research aimed at characterizing abundance, life history parameters, and ecological interactions within this newly expanded range are presented.