Once established, lionfish tend to stay close to home, study finds

Lionfish may quickly overcome native species in an area, but new research has found that they don’t wander very far. Findings from this research may aid efforts to control lionfish populations and estimate their movements.

To study lionfish movements, a group of researchers from North Carolina surgically inserted trackers into 25 lionfish and released them on two different dates, two months apart, at a hard bottom reef called “210 Rock” off of Cape Lookout, North Carolina. The team set up nine receivers around the study site, seven of which remained active for the entirety of the study, which lasted from December 2008 until June 2009. A control transmitter helped the team test the transmission signals since it was attached to one of the receivers and would not move very far.

The transmitter detection test showed that transmissions were best during the day and lowest at sunrise, and transmissions became weaker as water temperature rose. The team found that the detection ability of the transmitters was directly related to the environmental conditions each day.

Of the 25 lionfish released at 210 Rock, only 3 remained for the entire study. Five disappeared immediately after their release, and the other 17 disappeared at various times during the study. Nearly all lionfish moved farther from the time of their release in December (A group) or February (B group) until the end of April than they did during the summer months. A few fish from A group traveled for a long distance for a few days in April and May. Both groups exhibited more movement the week after their release than in subsequent weeks.

Researchers surmise that one of the reasons for the movements in the early spring is that lionfish cannot tolerate water temperatures below 14 degrees Celsius, so the water temperatures during the summer months may have been comfortable enough for them to stay in one location.

Estimated distances of movement ranged from 50 to 400 meters for the period of the study. Receivers were placed 300 to 350 meters apart to maximize coverage, as reception was lost at a 300m distance from the transmitters. Some fish seemed to move less than 200m throughout the study, while others traveled up to 400m. Researchers accounted for some variability, however, as the control transmitter (that was tied to one of the receivers) appeared to move about 200m.

The difference in movements suggests that lionfish have the potential to migrate into new territories, although once settled, they seem to stay around the same area.

Source: Bacheler, N.M., Whitfield, P.E., Muñoz, R.C., Harrison, B.B., Harms, C.A., and Buckel, C.A. (2015). Movement of invasive adult lionfish Pterois volitans using telemetry: importance of controls to estimate and explain variable detection probabilities. Marine Ecology Progress Series, 527:205-220. doi: 10.3354/meps11241

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