Fight or flight: an investigation of aggressive behavior and predator avoidance in two populations of blue crabs (Callinectes sapidus Rathbun) in New Jersey

Abstract

Recent literature has suggested aggression may be context dependent. The purpose of this investigation was to examine aggressive and predator avoidance behaviors in juvenile blue crabs of two populations. Furthermore, we wanted to determine whether aggression persisted into the adult stages. Juvenile blue crabs collected from an impacted estuary, the Hackensack Meadowlands (HM), were found to attack a threatening stimulus significantly more often (70%) than conspecifics from a less impacted estuary (Tuckerton-TK). TK juveniles responded significantly more often with a flight (*35%) or mixed response (*30%). Additionally, HM juveniles were significantly more successful than TK juveniles at avoiding an adult blue crab predator when sandy substrate was present in laboratory experiments. However, the video clarity made it impossible to determine which interactions were allowing survival. To determine if ''aggression'' exhibited by the HM juveniles was the reason for their enhanced survival, follow-up predator avoidance experiments were conducted without substrate and videotaped. The results of these experiments suggest that aggression per se is not the reason since aggressive juveniles were no more successful than non-aggressive individuals. The aggressive behavior exhibited by HM juveniles continues into the adult stages. This behavior may be important to recognize when estimating population size as well as local fishery efforts.

Population biology and distribution of the portunid crab Callinectes ornatus (Decapoda: Brachyura) in an estuary-bay complex of southern Brazil

“…Larger blue crabs behave aggressively toward conspecifics (CLARK et al 1999, REICHMUTH et al 2011, and might also be aggressive toward other species. We speculate that the presence of the other, larger Callinectes species such as C. danae (SANT'ANNA et al 2012a) in the estuary-bay complex may influence the distribution of C. ornatus, combined with the euryhalinity characteristic of the species.…”

Effects of the Parasite Loxothylacus texanus on the Agonistic Behavior of the Crab Callinectes rathbunae

“…Other researchers have observed that juvenile organisms of Callinectes sapidus are aggressive, react to external stimuli, such as foreign objects and they are cannibals, and these behaviors persist in adult stages (Hines and Ruiz, 1995;Clark et al, 1999;Hines, 2007;Reichmuth et al, 2011). Pedetta et al (2010) It was observed that in those parasitized crabs, the agonistic behavior decreased consistent with the maturation process of the externa.…”

Regional differences in foraging behaviour of invasive green crab (Carcinus maenas) populations in Atlantic Canada

“…During initial establishment at a new location, densities of green crabs increase rapidly, a phenomenon often associated with higher agonistic interactions in similar crab species (Clark et al 2000;Reichmuth et al 2011). Green crabs are generalist predators (Ropes 1968;Grosholz and Ruiz 1996;Klassen and Locke 2007), capable of depleting food resources in an area before moving on to new locations.…”

“…Although foraging success and aggression may be correlated (Reichmuth et al 2011) it is clear that they are not necessarily equivalent. For example, in a study on juvenile crab foraging, green crabs were first to the bait in competition experiments (therefore considered more successful foragers) but were less aggressive than blue crabs (Callinectes sapidus; MacDonald et al 2007).…”