Climate Change and Lionfish Go Hand in Hand

BY DANA TRICARICO

When marine scientists think of climate change, their mind may wander from those heartbreaking images of melting ice caps to more complex issues that are harder to see at first glance. There’s no doubt that, climate change aside, the ocean faces anthropogenic impacts from every direction. What happens to these threats in the face of our changing climate? Let’s dive into one example of a human-made problem that stands to get worse as seasonal cycles shift; the lionfish invasion.

 An invasive species is one that is non-native to a particular area AND is a threat to human health and/or the environment which it has invaded. Lionfish, originally from the Indo-Pacific, have effectively taken over reefs throughout the Caribbean, Gulf of Mexico and eastern Seaboard of the United States after likely being released into these waters in the 1980’s through the aquarium trade. They could harm humans with their venomous spines (if humans aren’t careful) and harm coral reef ecosystems by eating any native fish their gaping mouths can fit and swallow whole. With no native predators, an ability to reproduce year-round in large quantities and their wide-ranging thermal tolerance, lionfish show no signs of stopping their takeover. 

 Increasing ocean temperatures as a result of climate change can influence the growth and reproduction of marine life- specifically fish and invertebrates. This may not seem like such a bad idea for some native fish stocks that are decreasing from other anthropogenic threats, but for the voracious and invasive lionfish, this could mean catastrophic impacts to its new home waters. For example, a 2014 study by Whitfield et al demonstrates that warmer winters associated with climate change have the potential to expand lionfish population density in near-shore waters of North Carolina. 

 Based on a study published just this month by Steel et al, it looks like not only will the range they call home expand with warming water, but so will their appetite. In this study, feeding behavior was documented in winter temperatures and in peak summer temperatures. The findings? Lionfish can eat 42% more food during the months when the water is warmer. Unlike most fish, Lionfish direct more energy into digesting food than they do into swimming- a trait further exacerbated by the fact that they can fit 30 times their stomach volume at a given time. 

 While culling lionfish can’t hurt, it looks like they are not only in the Western Atlantic to stay. They will likely expand into new territories, eating more native species the warmer the ocean gets.

Stay involved, stay informed, and remember about those important ecosystems at risk below the waves. 

WOS editor, Dana Tricarico, does her part to cull the lionfish at Biscayne National Park in Homestead, Florida.