Feeding competition between the native oyster Crassostrea virginica and the invasive mussel Mytella charruana

Abstract

The subtropical mussel Mytella charruana has been reported as invasive along the southeast coast of the USA since 1986. This mussel has been found to negatively impact the keystone species in its invaded range, the eastern oyster Crassostrea virginica. To date, however, no mechanism for this negative impact has been determined. To elucidate the role of the invasive mussel on economically important oyster reefs, we compared the feeding physiology of both species in a lagoon along the east coast of Florida (USA). Three different methodologies were used: 1) in situ filter-feeding experiments using the biodeposition method to estimate feeding behavior; 2) laboratory assays to estimate the depletion of bacterial particles using a flow cytometer; and 3) stable isotope analysis in conjunction with ellipse-based metrics to investigate the niche size and overlap of these two species. The in situ filterfeeding experiments revealed that M. charruana had significantly higher clearance, filtration, rejection, organic ingestion and absorption rates, as well as higher rejection percentage and absorption efficiency, but rejected the same amount of inorganic particles. Flow cytometry data suggested that bacteria were a food source for both bivalve species. Stable isotope values confirmed that M. charruana and C. virginica filled similar functional niches in this ecosystem. These results suggest that M. charruana can outcompete native oysters, the findings also demonstrate that an invasion of M. charruana might significantly alter plankton abundance, potentially limiting food sources available to other less efficient native filter-feeders such as clams.

Effect of species diversity on particle clearance and productivity in farmed bivalves

“…Similarly, ribbed mussels increased their gut residence time when supplied with high concentrations of seston that contained relatively low nutritional content (Galimany et al 2013). Interspecific competition, particularly with non-native species, can overwhelm these adaptive post-ingestion processes, thereby constraining growth (Galimany et al 2017). Yet, seasonal differences in the ways that physiological and competitive processes interact among suspension feeders can also alter these dynamics (Riera et al 2002).…”

Ecological Mechanisms Underpinning Ecosystem Service Bundles in Marine Environments – A Case Study for Shellfish

“…For example, an 80% decline in filtering capacity was found when comparing past and present situations in Chesapeake bay (Zu Ermgassen et al, 2013b) and restoration of reefs can help regain lost services (Coen and Luckenbach, 2000;Grizzle et al, 2008;Baggett et al, 2015;Milbrandt et al, 2015). Filtration rates for invasive versus native species were compared, where invasive mussels were more efficient than native species that occupied similar niche space (Galimany et al, 2017a), thereby outcompeting them (Ruesink et al, 2006).…”

Spatial and temporal shifts in the diet of the barnacle Amphibalanus eburneus within a subtropical estuary

“…This variation impacts an organism’s ability to acquire, sort, and select food particles and may allow individual species to specialize in a subset of available suspended particulate matter ( Dubois et al, 2007a ; Riisgård & Larsen, 2010 ; Dubois & Colombo, 2014 ; Richoux, Vermeulen & Froneman, 2014 ; Cresson, Ruitton & Harmelin-Vivien, 2016 ; Whalen & Stachowicz, 2017 ). For example, bivalves are able to sort and selectively feed on particles, releasing inorganic matter via pseudofeces and efficiently retaining high quality particles greater than 5 μm ( Jørgensen, 1974 ; Møhlenberg & Riisgård, 1978 ; Riisgård, 1988 ; Galimany et al, 2017a , 2017b ). Tunicates, barnacles, and gastropod mollusks, in contrast, largely lack structures that facilitate particle selection and are considered generalist or indiscriminate suspension feeders ( Lesser et al, 1992 ; Petersen, 2007 ; Dubois et al, 2007a ; Cresson, Ruitton & Harmelin-Vivien, 2016 ).…”

“…Coastal ecosystems are subject to seasonal shifts in environmental conditions and strong resource gradients from a combination of inputs from marine and terrestrial sources ( Deegan & Garritt, 1997 ). In addition, food webs in these systems are increasingly impacted by anthropogenically-derived pollution and harmful algal blooms ( Carlton, Newman & Pitombo, 2011 ; Lapointe et al, 2015 ; Galimany et al, 2017b ). Divergence in feeding mechanisms among coexisting suspension feeders may lead to differential responses of species to these changes and shape community composition across sites ( Dubois et al, 2007a ; Cresson, Ruitton & Harmelin-Vivien, 2016 ).…”