Testing the efficacy of lionfish traps in the northern Gulf of Mexico
Spearfishing is currently the primary approach for removing invasive Indo-Pacific lionfish (Pterois volitans/miles complex) to mitigate their impacts to western Atlantic marine ecosystems. However, a substantial portion of lionfish spawning biomass is beyond the depth limits of SCUBA. Innovative technologies may offer an alternative means to target lionfish and allow for the development of a deepwater lionfish trap fishery, but the removal efficiency and potential environmental impacts of traps have not been evaluated. We tested a collapsible non-containment trap (the Gittings trap) near artificial reefs in the northern Gulf of Mexico. A total of 327 lionfish and 28 native fishes (4 of which regulated species) recruited to traps (i.e., number of fish observed within the trap footprint) during 82 trap sets, catching 144 lionfish and 29 native species. Lionfish recruitment was highest for single (versus paired) traps deployed <15 m from reefs with a 1-day soak time, for which mean lionfish and native species recruitment per trap were approximately 5 and 0.1, respectively. Gittings traps selected for larger lionfish (mean size 277 mm total length) compared to spearfishing (mean size 258 mm). Community impacts from Gittings traps appeared minimal given recruitment patterns and catch rates were >10X higher for lionfish versus native fishes. Gittings traps did not move on the bottom during two major storm events; however, further testing will be necessary to test trap movement with surface buoys. Additional research should also focus on design and operational modifications to improve Gittings trap deployment success (68% successfully opened on the seabed) and reduce lionfish escapement (56% escaped from traps upon retrieval). While removal efficiency for lionfish (12-24%) was far below that of spearfishing, study results demonstrate Gittings traps are suitable for future testing on deepwater natural reefs, which constitute >90% of the regions reef habitat.