Past research:
Broad salinity tolerance in the invasive lionfish Pterois spp. may facilitate estuarine colonization
As a generalist species, lionfish have been able to rapidly colonize a wide variety of ecosystems, including coral reefs, seagrass beds, mangroves, and the deep sea. While lionfish have been encountered in a number of estuarine systems, the spatial distribution of lionfish in estuaries is likely limited by the species’ ability to tolerate low salinities. Here, we experimentally identify minimum salinity tolerance in lionfish by measuring survival salinity minimum—the lowest salinity at which all individuals survive for 48 h. Additionally, we examine whether long-term exposure to low (but sub-lethal) salinities has negative effects on lionfish. Field observations in the Loxahatchee River estuary (Jupiter, FL) showed that lionfish can survive brief exposure to salinities as low as 1 ‰. Lionfish that were held at 7 ‰ for 28 days showed no differences in mortality, behavior or growth, when compared to control fish held at 35 ‰ (typical ocean salinity). This broad salinity tolerance may allow lionfish to colonize estuaries throughout their invaded range, and may facilitate dispersal across the Amazon-Orinoco plume. Because of the ecological and economic importance of estuaries, this facet of the lionfish invasion warrants further study.
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Lionfish alter benthic invertebrate assemblages in patch habitats of a subtropical estuary
Invasive lionfish (primarily Pterois volitans) have spread throughout the Caribbean region, Gulf of Mexico, and the Southeast US coast, and resulting impacts on reef fish populations have been well documented. We examined whether lionfish can likewise affect benthic invertebrate communities, using an in situ caging experiment, in the Loxahatchee Estuary, Florida, USA. We found that lionfish caused significant declines in the three most abundant benthic invertebrate species, driving an overall shift in assemblage composition. For example, grass shrimp (Palaemonidae) abundance was reduced by nearly 90 % in the presence of lionfish. Species richness of benthic organisms was significantly higher when lionfish were present, suggesting potentially complex emergent effects of lionfish predation on benthic assemblages. Despite the fact that this experiment was conducted in just a single location using relatively small experimental units, we show altered benthic invertebrate communities could well be an additional outcome of the lionfish invasion.
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