Two-tiered defense strategy may compensate for predator avoidance costs of an ecosystem engineer

Comparison of Nursery Methods to Strengthen Oysters for Aquaculture

“…Organisms may add calcium carbonate to their shells in response to predation risk, which can be added quickly to reach a size refuge and is energetically less expensive than adding organic tissue Taylor 1974, Currey andHughes 1982). In contrast, adding organic tissue increases shell strength, but is costlier for growth and fecundity (Frieder et al 2016, Scherer et al 2018. Oysters react to low risk levels by adding calcium carbonate and increasing in size and weight, without increasing in shell strength, but at higher risk levels, also add protein to their shells to increase strength (Scherer et al 2018).…”

“…In contrast, adding organic tissue increases shell strength, but is costlier for growth and fecundity (Frieder et al 2016, Scherer et al 2018. Oysters react to low risk levels by adding calcium carbonate and increasing in size and weight, without increasing in shell strength, but at higher risk levels, also add protein to their shells to increase strength (Scherer et al 2018). Differences in shell responses to predator cues between spat-on-shell and seed oysters may therefore be a consequence of different perceptions of predation risk as spat-on-shell exhibited characteristics of a low to moder-ate threat.…”

“…Oysters respond to chemical exudates from injured con-and hetero-specifics as well as predator exudates by building thicker shells and altering the composition of shells (Scherer et al 2016). Bivalves, including oysters, may increase the addition of calcium carbonate to make shells larger, add protein to their shells to increase its strength, or both (Currey and Taylor 1974, Frieder et al 2016, Scherer et al 2018.…”

Cloudy with a chance of mesopredator release: Turbidity alleviates top‐down control on intermediate predators through sensory disruption

“…On turbid reefs, crab mesopredators were 260% more abundant, and oyster abundance was lower, likely due to predation by crabs. Moreover, oysters were smaller and grew stronger shells in high turbidity, a response known to occur in response to crab exudates (Scherer et al 2016(Scherer et al , 2018. Juvenile oysters likely had to reallocate energy away from somatic growth and reproduction and toward fortifying shell defenses (Scherer et al 2018).…”

Individual and population level effects of ocean acidification on a predator-prey system with inducible defenses: bryozoan-nudibranch interactions in the Salish Sea

“…Predator-induced defenses are common in marine calcifiers, e.g. shell thickening in oysters (Lord & Whitlatch 2012, Scherer et al 2018, snails (Trussell & Nicklin 2002, Bourdeau 2010), and mussels (Leonard et al 1999). OA has been found to affect inducible defenses in some species.…”