Differences in Relative Predation Vulnerability Between Native and Non-native Oyster Larvae and the Influence on Restoration Planning in an Estuarine Ecosystem

Abstract

The costs and benefits of non-native introductions as a restoration tool should be estimated prior to any action to prevent both undesirable consequences and waste of restoration resources. The suggested introduction of nonnative oyster species, Crassostrea ariakensis, into Chesapeake Bay, USA, provides a good example in which the survival of non-native oysters may differ from that of native oysters, Crassostrea virginica, during the larval stage. Experiments were conducted to compare the predation vulnerability of native and non-native oyster larvae to different predator types (visual vs. non-visual, benthic vs. pelagic). The results suggest that the non-native larvae are more vulnerable to visual and non-visual pelagic predators. Although vulnerability was similar for larvae exposed to benthic non-visual predators, the consumption of one nonnative strain was higher than the consumption of native C. virginica larvae. When vulnerability data are combined with predator feeding rates, the predation mortality for nonnative larvae in the wild can be much higher than for native larvae. Small changes in larval mortality rates can yield large changes in total larval delivery to the reef for settlement, so these differences among species may contribute to differences in settlement success. These results provide an example of how a comprehensive examination of the perceived benefits of non-native introductions into complex ecosystems can provide important information to inform management decisions.

Natural Populations of Shipworm Larvae Are Attracted to Wood by Waterborne Chemical Cues

“…If swimming activity incurs costs, e.g. increased predation risk [ 63 ], an option may be to increase swimming velocity only within the envelope of a waterborne cue and thus enhance encounter rate with the substrate when swimming through the boundary layer. Although Chan et al [ 64 ] recently showed that gastropod larvae significantly modify the swimming velocity through adjustment of velum extension there is yet no information about this mechanism in shipworm larvae or in response to a chemical cue.…”

Large and mesoscale meteo-oceanographic patterns in local responses of biogeochemical concentrations

“…Environmental changes affect species in many different ways, altering their productivity and interactions with other species and understanding these effects of ecosystems is a challenge for research management (Breitburg et al 1999;Harrington et al 1999). Intentional changes for ecosystem management represent an investment to improve ecosystem services, such as fishing or aquaculture production, but can also pose risk interactions between native and non-native species and it may have unintentional consequences on the environment (Fulford and Breitburg 2011).…”

Interactions of larval dynamics and substrate preference have ecological significance for benthic biodiversity and Ostrea edulis Linnaeus, 1758 in the presence of Crepidula fornicata

“…This occurs through the production of mucoidal pseudofaeces, which converts predominantly sandy substrata into mud-dominated substrata with a high organic content that rapidly becomes anoxic and unsuitable for other species (Streftaris & Zenetos, 2006). This includes oysters that prefer less silty and muddy waters (Barnes et al, 1973;Bromley, McGonigle, Ashton, & Roberts, 2016;Fulford, Breitburg, & Luckenbach, 2011;Walne, 1979).…”

“…This occurs through the production of mucoidal pseudofaeces, which converts predominantly sandy substrata into mud‐dominated substrata with a high organic content that rapidly becomes anoxic and unsuitable for other species (Streftaris & Zenetos, 2006). This includes oysters that prefer less silty and muddy waters (Barnes et al, 1973; Bromley, McGonigle, Ashton, & Roberts, 2016; Fulford, Breitburg, & Luckenbach, 2011; Walne, 1979). Ostrea edulis populations are also negatively impacted through a reduction in suitable substrata available for larval settlement (Blanchard, 1997), hindering recruitment and potentially oyster restoration efforts on the seabed.…”