The Importance of Marine Bivalves in Invasive Host–Parasite Introductions

Abstract

Although research into the ecology and impacts of invasive species is prevalent, there are knowledge gaps relating to the role of invasive species in parasite transmission. This work synthesises invasive host–parasite interactions and impacts, using marine bivalves as a model group, to consider how global movement of shellfish consignments for aquaculture purposes facilitates the unintentional transfer of invasives. We discuss how invasive species can act as both hosts or parasitic organisms themselves, and introductions may lead to diseases within the bivalve aquaculture sector. This review highlights the importance of interdisciplinary research, with particular regard to the fields of parasitology and invasion ecology. We suggest that further integrating these fields will enhance critical knowledge of marine diseases, parasite-invasive-bivalve interplay dynamics, and potential mitigation strategies, including temperature-based disease surveillance models. We also address how climate change might impact invasive species, again with a focus on marine bivalves, and the potential outcomes for parasite transmission, including changes in host/parasite distribution, life-history and virulence. We acknowledge the importance of horizon scanning for future invasive host–parasite introductions and note that increased screening of invasive species, both in their native and invaded ranges, will provide clarity on invasion dynamics and potential impacts.

Guests or pests? Eirenid hydroids living on the soft tissue of bivalves

“…food availability). Eugymnanthea inquilina in M. galloprovincialis from the North Adriatic Sea peaked in late summer (prevalence 86.7%, T = 20.3°C) and declined in winter (37%), with an average sea temperature of 9.1°C, 14 but never entered dormancy, suggesting that this species has a wider thermal tolerance limit than other eirenids.…”

“…In the North Adriatic Sea, salinity and oxygen content have a statistically significant correlation with E. inquilina infection: a hydroid prevalence peak was reported in September (oxygen 6.9 mg/L and salinity of 39‰), while the lowest values occurred in March (oxygen 11.6 mg/L, salinity 32.5‰ 14 ).…”

Managing risk of non‐indigenous species establishment associated with ballast water discharges from ships with bypassed or inoperable ballast water management systems

“…Non‐indigenous species (NIS) are a leading cause of biodiversity loss (Duenas et al, 2018), especially in aquatic ecosystems (Clavero & García‐Berthou, 2005). NIS directly affect native species through predation (Albins & Hixon, 2013; Jänes et al, 2015; Pratchett et al, 2017), competitive displacement (Katsanevakis et al, 2014; Pyšek et al, 2017), parasitism (Costello et al, 2021; Dunn et al, 2012; Goedknegt et al, 2016) and complex ecosystem alterations (David et al, 2017; Kelly et al, 2010; Kotta et al, 2018; Zeug et al, 2014).…”

The immunobiology of Crepidula fornicata and its potential to act as a harbourer of infectious disease

“…IAS that act as vectors for infectious agents can cause parasite "spillover" into native populations, causing an emerging disease (Costello et al, 2021). When an invasive species acts as an alternative host for native or already established parasites, they may result in the parasite population size rising, leading to increased levels of infection in native host populations, i.e.…”

“…protozoa, bacteria, and viruses) that show high rates of direct reproduction within the host (Anderson and May, 1979). Both macro-and micro-parasites can affect both wild aquatic species and commercial species used in cultured systems and local, often traditional, shellfisheries (Costello et al, 2021).…”