A dynamical model for invasive round goby populations reveals efficient and effective management options

Abstract

Abstract1. When prevention of invasive species' introductions fails, society faces the challenge to manage invasive species in an effective and efficient way. The success of this depends on biological aspects and on cooperation between decision makers and scientists.Using the case of the round goby Neogobius melanostomus, one of Europe's "worst invasive species", we propose an approach guiding scientists to co-produce effective and efficient population control measures in collaboration with decision makers.2. We surveyed the effectiveness, urgency and simplicity perceived by decision makers as well as the support of two population control options: removal of eggs and/ or adults. Using a field study and a dynamical population model, we investigated the effectiveness and efficiency for both options in different population contexts.3. Decision makers initially seemed to lack a clear preference for either control option.After being presented with preliminary field and modelling results, decision makers mostly approved measures being developed to implement the two control options.4. Starting population control early after detecting the species requires in total fewer years for eradication than controlling an established population: to reach an eradication success rate of 95%, 13 years for early start vs. 18 years for late start are needed when removing eggs and adults; when removing adults only, 20 vs. 29 years are needed. Removing eggs and adults combined results in a yearly effort of 5.01 h/m 2 , while removing adults only results in a yearly effort of 1.76 h/m 2 . Thus, removing adults only proves to be the most efficient option to eradicate the population. Nonetheless, considerable effort is needed: when removing less than 57% of the adult population, eradication is not feasible, even assuming low survival and fecundity rates for the population. Furthermore, inflow of new propagules renders eradication efforts ineffective. Synthesis and applications.Scientists who aim to support decision makers in finding an optimal control strategy for invasive species need to be able to provide scientific knowledge on effectiveness and efficiency of different options. For round goby and most non-native species, eradication is only feasible if started early in recently arrived populations and if inflow of new propagules can be prevented.

Passive acoustic monitoring shows no effect of anthropogenic noise on acoustic communication in the invasive round goby (Neogobius melanostomus)

“…It can be difficult to monitor round goby populations using traditional methods because of their sheltering activity (Ray & Corkum, ) and there is great interest in effective monitoring to track their spread into new areas. While early detection of new life stages of migrants has been attempted (Kornis et al., ; Phillips, Washek, Hertel, & Niebel, ), a better use of control strategies (Isabella‐Valenzi & Higgs, ; N'Guyen et al., ) might be to target breeding populations for effective use of limited resources. Passive acoustic monitoring is in its infancy as a tool for invasive species monitoring (Juanes, ; Rountree & Juanes, ; Rountree et al., ) but has potential as a low‐cost and effective monitoring tool for at least soniferous species (Luczkovich et al., ).…”

“…While early detection of new life stages of migrants has been attempted (Kornis et al, 2012;Phillips, Washek, Hertel, & Niebel, 2003), a better use of control strategies (Isabella-Valenzi & Higgs, 2016;N'Guyen et al, 2017) might be to target breeding populations for effective use of limited resources. Passive acoustic monitoring is in its infancy as a tool for invasive species monitoring (Juanes, 2018;Rountree & Juanes, 2017;Rountree et al, 2006) but has potential as a low-cost and effective monitoring tool for at least soniferous species (Luczkovich et al, 2008).…”

Decision‐making for mitigating wildlife diseases: From theory to practice for an emerging fungal pathogen of amphibians

“…This approach is particularly useful considering that decision analysis is an iterative process, where different components can be revisited as needed. For example, new actions could be devised using the initial results as an indication of the effects of manipulating different model parameters (N'Guyen et al., ).…”

“…Therefore, we used a formal expert elicitation process to estimate the model parameters; this ensured that all evidence available was incorporated, while making explicit any additional uncertainty expressed by experts. We carried out the elicitation in a group of 10 experts (all listed co-authors except SC, CB and EG, who acted as facilitators) during a 4-day workshop, using a best-practice approach (Martin et al, 2012). For each parameter, each expert was initially asked to provide estimates individually (minimum, most likely and maximum values), then allowed to revise those after group discussions based on critically evaluated published and unpublished evidence.…”

Egg predation on native fish by invasive round goby revealed by species-specific gut content DNA analyses

“…Based on existing population control models (N'Guyen et al, 2018), eradication of round goby in secluded areas might be achieved by a long-term yearly removal of 85% of all the population's adult individuals. Our own experience with sampling in 2018 and participation in the 2017 electrofishing campaign indicates that round goby populations at the nase spawing site can be substantially reduced by electrofishing.…”