Meeting Abstract
The invasive European green crab has detrimental effects on soft shell clam (Mya arenaria) populations and clam fisheries have collapsed due to green crab invasions. Growing evidence supports the idea that trophic interactions between predator and prey have the ability to alter morphological and physiological. These shifts in prey species have the potential to alter future predator/prey interactions. This project investigates morphological and physiological changes in both juvenile and young adult soft shell clam populations when subjected to varying densities of green crab presence. Juvenile and young adult clams were exposed to green crab chemical cues in three different densities: control (no crabs), low predation (3 crabs/0.15m2), and high predation (7 crabs/0.15m2). Juvenile clams were exposed to the crabs for six months, and the young adult clams for 72 hours. Juvenile clams were measured for shell length, siphon length, AMPK activity, HSP70, and RNA:DNA ratio, while young adults were tested for AMPK, RNA:DNA ratio, HSP70, shell opening, heart rate, and oxygen consumption (last three adult parameters tested with varying levels of both predator and conspecific chemical cues). First results for juveniles exhibit increased siphon length and reduced siphon thickness, as well as reduced shell length in the low predation density. Exposing adult clams to predatory chemical cues leads to reduced frequency of shell opening. Ongoing analyses of cellular stress parameters explore the underlying cellular mechanism. Our preliminary results indicate that the presence of predators affects growth rates and/or energy utilization in clams, with subsequent effects on the shellfish industry.
