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

Abstract

Invasive green crab populations initially established in Canada within the Bay of Fundy, New Brunswick in the 1950s and were present in all five Atlantic provinces by 2007. Genetic evidence suggests that the Atlantic Canadian populations originated from two separate introductions with differences in time of establishment among regions and possible populationlevel behavioural differences. In this study, we examine intraspecific foraging behaviour among crabs from different populations, and interspecific foraging behaviour between genetically similar crabs and juvenile lobsters. Both sets of foraging experiments involved competition for a limited food source over a 1-h period. In intraspecific match-ups, recent invaders from Newfoundland (NL) were significantly superior foragers than long-established invaders from Nova Scotia (NS) and New Brunswick (NB) populations; however, we found no differences between NL and Prince Edward Island (PE) invaders. Crabs from PE were better competitors than those from NS and NB, but these differences were not significant. Interspecific competition experiments indicated that the feeding behaviour of recent invaders (NL) and genetically similar, but long-established invaders (NS), differed in the presence of juvenile lobsters. Our study documents striking behavioural differences among populations of green crab from a small geographic region, which may reflect a combination of both genetic differences and time since establishment. These differences may result in varying impacts on newly invaded habitats.

The trophic position of the Atlantic blue crab Callinectes sapidus Rathbun 1896 in the food web of Parila Lagoon (South Eastern Adriatic, Croatia): a first assessment using stable isotopes.

“…The green crab, similarly to C. maenas, is a voracious shore predator, preying especially on molluscs (Sanchez-Salazar et al, 1987), and is an active scavenger (Moore & Howarth, 1996;Bergmann et al, 2002). It is characterized by trophic habits similar to those shown by adult blue crabs (Hines, 2007); however, its size at maturity is much smaller than that of the blue crab (Berrill, 1982;Kennedy & Cronin, 2007), it is less aggressive and thus http://epublishing.ekt.gr | e-Publisher: EKT | Downloaded at 11/05/2018 23:10:53 | more susceptible to negative competitive and predatory interactions (Rossong et al, 2012). Indeed, C. sapidus is acknowledged as a major predator of C. maenas in North American coastal habitats, where the green crab is an invasive species, and at high enough densities can limit green crab populations (deRivera et al, 2005(deRivera et al, et al, 2005; see also Johnson, 2015).…”

Advancing impact prediction and hypothesis testing in invasion ecology using a comparative functional response approach

“…1b-d). Further, Dick et al (2013) showed that differential functional responses are consistent across the invader's geographical range (see also Lohrer et al 2000), thus demonstrating that this technique offers advantages over other trait-based predictions, since other traits often vary across an invader's range (Olden et al 2006;Rossong et al 2012;Parker et al 2013). At present, there are insufficient studies to perform a formal meta-analysis to test the overall hypothesis that ecologically damaging invasive species have higher functional responses than comparator native species (see Table 1).…”

Revisiting recent history: records of occurrence and expansion of the European green crab across Prince Edward Island, Atlantic Canada

“…The arrival and mixing of genotypes from populations originating from northern and southern Europe is believed to have facilitated the northern spread of green crab populations in Atlantic Canada. Moreover, this mix of populations may have modified some physiological and behavioural traits across subpopulations (Blakeslee et al 2010, Rossong et al 2012. For example, green crabs from areas most recently invaded (Newfoundland and Prince Edward Island) have been shown to be more aggressive and more successful in competitive trials against a native species than those from areas invaded several decades ago (e.g.…”

“…Genetic analyses have also indicated that a separate introduction occurred along the eastern Scotian shelf in the 1980's (Roman 2006;Blakeslee et al 2010) which has resulted in a mixing of northern and southern European green crab genotypes. Evidence suggests that this mixing may have widened the species' environmental tolerance locally, likely contributing to physiological and behavioural changes across subpopulations (Blakeslee et al 2010, Rossong et al 2012. It is also thought that this genetic mixing may have accelerated the species' eastward spread along the Nova Scotian coast (Blakeslee et al 2010) despite prevalent downstream current systems (Brickman 2014;Gharouni et al 2017).…”