Top-down effects of predators in systems depend on the rate at which predators consume prey, and on predator preferences among available prey. In invaded communities, these parameters might be difficult to predict because ecological relationships are typically evolutionarily novel. We examined feeding rates and preferences of a crab native to the Pacific Northwest, Cancer productus, among four ...

Most hermit crabs have a specialized lifestyle that requires them to occupy gastropod shells. The size of shells that hermit crabs inhabit relative to their body size affects their growth, survival and fecundity. In this study, the effects of shell fit on individual growth rate, risk of predation, feeding rate, and activity level were examined in the laboratory for hermit crabs Pagurus longicar...

Pea crabs are globally ubiquitous symbionts in the marine environment that cause serious economic impact in the aquaculture production of several major bivalve species. However, little is known about their host-parasite interactions, especially the mating behaviour of these parasites that could prove useful for controlling their infestation in aquaculture. In this study, the mate location behav...

A survey of recreational boat-based and shore-based fishing in the Swan-Canning Estuary Basin was conducted between August 1998 and July 1999. During the survey 1,302 interviews were conducted at boat ramps. The majority of these (62%) were not involved in fishing or crabbing activities, with a further 18 per cent fishing in the adjacent ocean. Of the remainder, 139 boats had been crabbing and ...

Each spring adult horseshoe crabs migrate from deep bay waters and the Atlantic continental shelf to intertidal sandy beaches to spawn. Horseshoe crabs are an important food source for migrating shorebirds that feed on the eggs, for migrating fish that feed on the eggs and larvae and for Atlantic loggerhead turtles that feed on horseshoe crabs while using the Chesapeake Bay as a summer nursery ...

The interactive effects of predator density and prey distribution on the foraging behavior of an important estuarine predator were studied, at a fine temporal scale, using ultrasonic telemetry. The movement and agonistic activity of individual blue crabs Callinectes sapidus were monitored in large field enclosures, in which the density of crabs and the distribution of patches of bivalve prey Ma...

An aluminum smelter situated at the head of Kitimat Arm (BC, Canada) has discharged polycyclic aromatic hydrocarbons (PAHs) into the receiving waters since 1954. The purpose of the present study was to examine the distribution of PAHs contaminants in dungeness crabs (Cancer magister) collected in Kitimat Arm and Douglas Channel (BC, Canada) by determining the concentrations of PAHs in the hepat...

Most oceanic islands harbor unusual and vulnerable biotas as a result of isolation. As many groups, including dominant competitors and predators, have not naturally reached remote islands, others were less constrained to evolve novel adaptations and invade adaptive zones occupied by other taxa on continents. Land crabs are an excellent example of such ecological release, and some crab lineages ...

Commercial Atlantic blue crabs (Callinectes sapidus) were exposed to 2.0x10(4) infectious waterborne oocysts of Cryptosporidium parvum. The study demonstrated that blue crabs can transfer C. parvum oocysts to persons involved in handling or preparing crabs and that they may contaminate other surfaces or products during storage.