scholarly journals Niche segregation between American lobster Homarus americanus and rock crab Cancer irroratus

1989 ◽  
Vol 52 ◽  
pp. 155-168 ◽  
Author(s):  
C Hudon ◽  
G Lamarche
PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8444
Author(s):  
Nicola Zargarpour ◽  
Cynthia H. McKenzie ◽  
Brett Favaro

Marine species invasions pose a global threat to native biodiversity and commercial fisheries. The European green crab (Carcinus maenas) is one of the most successful marine invaders worldwide and has, in the last decade, invaded the southern and western coastal waters of the island of Newfoundland, Newfoundland and Labrador (NL), Canada. Impacts of green crab on the American lobster (Homarus americanus), which are native to Newfoundland, are not well understood, particularly for interactions around deployed fishing gear. Declines in lobster catch rates in invaded systems (i.e., Placentia Bay, NL), have prompted concerns among lobster fishers that green crab are interfering with lobster catch. Here, we conducted a field experiment in a recently-invaded bay (2013) in which we deployed lobster traps pre-stocked with green crab, native rock crab (Cancer irroratus) (a procedural control), or empty (control). We compared catch per unit effort across each category, and used underwater cameras to directly observe trap performance in situ. In addition, we used SCUBA surveys to determine the correlation between ambient density of lobster and green crab in the ecosystem and the catch processes of lobster in traps. We found: (1) Regardless of the species of crab stocked, crab presence reduced the total number of lobster that attempted to enter the trap, and also reduced entry success rate, (2) lobster consumed green crab, rock crab and other lobster inside traps and (3) there was a positive association between lobster catch and ambient lobster density. Our results suggest that while there was a relationship between in-trap crab density and trap catch rates, it was not linked to the non-native/native status of the crab species.


1995 ◽  
Vol 52 (2) ◽  
pp. 315-324 ◽  
Author(s):  
R. J. Miller ◽  
J. T. Addison

The relationship between trap catches of decapods and their abundance is not well established. Because it is difficult to manipulate density in the field, laboratory tanks were used to examine 10 hypotheses about the intra- and interspecific interactions of rock crab (Cancer irroratus), green crab (Carcinus maenas), and American lobster (Homarus americanus). The proportion of rock crabs captured did not differ among high, medium, and low densities, but the proportion captured was reduced at high densities for both green crabs and lobsters. Additional experiments demonstrated that large green and rock crabs in the tanks reduced the catch of small green and rock crabs and that the presence of lobsters reduced the catch of both crab species considerably. However, small rock crabs did not reduce the catch of large rock crabs, and neither green nor rock crabs reduced the catch of each other. Reductions in the catch of a target species caused by interactions in the field can perhaps be lessened by removing the catch from the trap at intervals of less than 24 h. Then the catches would be summed over 24 h for an index of abundance.


1979 ◽  
Vol 36 (5) ◽  
pp. 537-543 ◽  
Author(s):  
Robert W. Elner ◽  
Glen S. Jamieson

Various predation techniques used by rock crabs, Cancer irroratus, and American lobsters, Homarus americanus, to open sea scallop, Placopecten magellanicus, prey are reported. Adult rock crabs and lobsters successfully fed on sea scallops up to 72 and 76 mm in height, respectively. Juvenile lobsters were capable of preying on scallops whose height exceeded their own carapace length. Daily predation rates on a range of scallop sizes by various sizes of predator were obtained. Given a choice, both rock crabs and lobsters showed distinct and constant preferences for certain size scallops. This preferred prey size increased with predator size. These laboratory studies demonstrated that both rock crabs and lobsters are potential scallop predators. Key words: sea scallops, crabs, lobsters, predation techniques, prey selectivity


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