Remove or capture non-native, invasive or other problematic species
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
Background information and definitions
Non-native, invasive and other problematic species can impact on native subtidal benthic invertebrate species through predation, competition for resources (food & space), contamination (from pathogens and diseases), or hybridization (through reproduction) (Molnar et al. 2008; Bishop et al. 2010). Physical removal can be used to attempt to control populations of non-native, invasive or other problematic species (Hewitt et al. 2005; Thresher & Kuris 2004). Physical removal can be achieved by using tools (Piazzi & Ceccherelli 2006), manually (Hewitt et al. 2005; Wright et al. 2005), or through capture (Calderwood et al. 2015). Capture can be carried out for instance by using sex pheromones or baited traps to attract the target species (Calderwood et al. 2015).
For example, problematic overgrazing sea urchins, for instance due to range extension, can cause a shift from kelp forests to barren areas (Wright et al. 2005). Their removal can allow for the kelp forest to recover over time (Wright et al. 2005), and in turn help subtidal benthic invertebrates associated with kelp forest recover as well.
Bishop M.J., Krassoi F.R., McPherson R.G., Brown K.R., Summerhayes S.A., Wilkie E.M. & O’Connor W.A. (2010) Change in wild-oyster assemblages of Port Stephens, NSW, Australia, since commencement of non-native Pacific oyster (Crassostrea gigas) aquaculture. Marine and Freshwater Research, 61, 714–723.
Calderwood J., O'Connor N.E. & Roberts D. (2015) Effects of baited crab pots on cultivated mussel (Mytilus edulis) survival rates. ICES Journal of Marine Science, 72, 1802–1810.
Hewitt C.L., Campbell M.L., McEnnulty F., Moore M.M., Murfet N.B., Robertson B. & Schaffelke B. (2005) Efficacy of physical removal of a marine pest: the introduced kelp Undaria pinnatifida in a Tasmanian Marine Reserve. Biological Invasions, 7, 251–263.
Molnar J.L., Gamboa R.L., Revenga C. & Spalding M.D. (2008) Assessing the global threat of invasive species to marine biodiversity. Frontiers in Ecology and the Environment, 6, 485–492.
Thresher R., Grewe P., Patil J.G., Whyard S., Templeton C.M., Chaimongol A., Hardy C.M., Hinds L.A. & Dunham R. (2009) Development of repressible sterility to prevent the establishment of feral populations of exotic and genetically modified animals. Aquaculture, 290, 104–109.
Wright J.T., Dworjanyn S.A., Rogers C.N., Steinberg P.D., Williamson J.E. & Poore A.G. (2005) Density-dependent sea urchin grazing: differential removal of species, changes in community composition and alternative community states. Marine Ecology Progress Series, 298, 143–156.
Supporting evidence from individual studies
A replicated, controlled, before-and-after study in 2004–2006 of 20 plots in one rocky reef area of the southwest Atlantic, Brazil (De Paula et al. 2017) found that after a year, the effect of removing the invasive corals Tubastraea coccinea and Tubastraea tagusensis on the cover of native zoanthid Palythoa caribaeorum and native sponges varied with the removal method used. Sponge cover was greater in plots where multiple removals of invasive corals occurred (35%), and lower in plots where removal occurred once (15%), where the whole seabed community was removed once (21%), and where no removal occurred (17%). Zoanthid cover was lower in the single-removal plots (10%) compared to the no-removal plots (22%), while community-removal plots were never recolonised (0% cover after a year). Zoanthids were absent from the multiple-removal plots before removal and did not colonise over time. After a year, invasive corals had recolonised all removal plots (single-removal: 14%; multiple-removal: 3%; community-removal: 14%; no removal: 27%). The two corals invaded the reef approximately 20 years prior. Twenty 0.16 m2 plots, all with ≥20% cover of invasive corals were selected. Four treatments were used (5 plots/treatment): a single removal of invasive corals (December 2004), multiple removals of invasive corals, a single removal of the whole community (December 2004), and no removal. Removal was done manually by divers. Before, immediately after first removal, and on eight occasions afterwards, divers counted corals, zoanthids and sponges in each plot, and removed invasive corals in the multiple removal treatment. Before removal, all plots had similar covers of sponge and zoanthids (apart from multiple-removal plots where zoanthids were absent).Study and other actions tested