Low Susceptibility of Invasive Red Lionfish (Pterois volitans) to a Generalist Ectoparasite in Both Its Introduced and Native Ranges

Abstract

Escape from parasites in their native range is one of many mechanisms that can contribute to the success of an invasive species. Gnathiid isopods are blood-feeding ectoparasites that infest a wide range of fish hosts, mostly in coral reef habitats. They are ecologically similar to terrestrial ticks, with the ability to transmit blood-borne parasites and cause damage or even death to heavily infected hosts. Therefore, being highly resistant or highly susceptible to gnathiids can have significant fitness consequences for reef-associated fishes. Indo-Pacific red lionfish (Pterois volitans) have invaded coastal habitats of the western tropical and subtropical Atlantic and Caribbean regions. We assessed the susceptibility of red lionfish to parasitic gnathiid isopods in both their native Pacific and introduced Atlantic ranges via experimental field studies during which lionfish and other, ecologically-similar reef fishes were caged and exposed to gnathiid infestation on shallow coral reefs. Lionfish in both ranges had very few gnathiids when compared with other species, suggesting that lionfish are not highly susceptible to infestation by generalist ectoparasitic gnathiids. While this pattern implies that release from gnathiid infestation is unlikely to contribute to the success of lionfish as invaders, it does suggest that in environments with high gnathiid densities, lionfish may have an advantage over species that are more susceptible to gnathiids. Also, because lionfish are not completely resistant to gnathiids, our results suggest that lionfish could possibly have transported blood parasites between their native Pacific and invaded Atlantic ranges.

Parasitism inPterois volitans(Scorpaenidae) from Coastal Waters of Puerto Rico, the Cayman Islands, and the Bahamas

“…Here, we present results from a 4 yr study of the parasites of invasive red lionfish that included a total of 326 samples from 3 different island groups. These include Puerto Rico and Cayman Islands (lionfish appeared in 2008 at both sites) (Schofield, 2009), which have not been previously studied, and the Bahamas, where only Gnathia marleyi Farquharson, Smit & Sikkel, 2012, has been previously reported infecting caged lionfish (Sikkel et al, 2014). This study therefore provides the first comprehensive assessment of parasites from invasive P. volitans from the broader Caribbean region.…”

“…Records of parasites from invasive lionfish in the tropical western Atlantic include a leech attached to the tongue of a male lionfish from Jacksonville, Florida (Ruiz-Carus et al, 2006), which was identified as Trachelobdella lubrica Grube, 1840, after reexamination by Bullard et al (2011); the trematode Lecithochirium floridense (Manter, 1934) in lionfish stomachs from North Carolina (Bullard et al, 2011); and an isopod from the genus Excorallana from Bonaire (Poole, 2011). Gnathiid isopods were observed infecting lionfish from the Cayman Islands, Virgin Islands, and the Bahamas (Sikkel et al, 2014); however, these were on lionfish held in cages near to heavily infected native fishes, and so these cannot be considered as a record of naturally occurring parasites of invasive P. volitans. Here, we present results from a 4 yr study of the parasites of invasive red lionfish that included a total of 326 samples from 3 different island groups.…”

Lionfish: a major marine invasion

“…Native predators are apparently de - terred by the unusual shape, cryptic coloration, and venomous spines of lionfish, although there is debate regarding whether large native groupers are a major threat to the invader (Mumby et al 2011, Hackerott et al 2013, Valdivia et al 2014. Few parasites attack invasive lionfish (Sikkel et al 2014), native mesopredators appear to be ineffective competitors (Albins 2013), and even highly territorial damselfish do not chase them (Kindinger 2015). Additionally, lionfish use a variety of feeding behaviors, including ambushing and corralling prey (Morris & Akins 2009), as well as blowing jets of water at prey (Albins & Lyons 2012).…”

Lionfish cause increased mortality rates and drive local extirpation of native prey

“…These voracious, generalist predators have strong direct effects on native prey fishes via consumption of newly settled recruits and adults of small species (Albins & Hixon 2008, Albins 2013, Côté et al 2013, Benkwitt 2015, Ingeman & Webster 2015 and have the potential to alter invaded reef ecosystems directly through consumption of ecologically important native fishes and via the indirect effects of predation (Albins & Hixon 2013). To date, few biotic controls have been identified in the invaded range: Atlantic lionfish are relatively free of parasites (Sikkel et al 2014) and do not experience increased mortality or emigration even at extreme densities (Benkwitt 2013). Lionfish possess an impressive array of traits that may render them difficult to detect and/or may confuse prey (Lönnstedt & McCormick 2013, Marsh-Hunkin et al 2013, Black et al 2014 and are themselves well-defended from predation by venomous dorsal spines (Halstead et al 1955).…”