Deep shift: an introduced seagrass, Halophila stipulacea, expands nursery habitat for Caribbean juvenile fish into deeper waters

Seagrass beds provide essential habitat for many fish species. This study utilized over a decade (2009 to 2022) of annual seagrass monitoring data to investigate trends in seagrass composition with the introduction of the non-native species, Halophila stipulacea. Fish community surveys, as well as benthic community surveys, were also conducted within soft bottom habitat of two Caribbean bays in 2023. Seagrass composition saw a shift from sparse mixed native beds dominated by Syringodium filiforme to mixed beds dominated by H. stipulacea whose percent cover fluctuated with storms. In 2023, benthic surveys provided evidence that the introduction of H. stipulacea expanded the nursery habitat for commercially important species into soft bottom areas deeper than 15 meters. This shift in seagrass composition expands available habitat for local seagrass-associated fish communities, including commercially important species such as yellowtail snapper (Ocyurus chrysurus) and lane snapper (Lutjanus synagris) into depths beyond the reach of native seagrasses, expanding available habitat and potentially providing a thermal refuge.