MEPS 256:171-182 (2003)  -  doi:10.3354/meps256171

Offense versus defense: responses of three morphological types of lobsters to predation

Diana E. Barshaw1,4,*, Kari L. Lavalli1,3, Ehud Spanier1,2

1Leon Recanati Institute for Maritime Studies, and
2Department for Maritime Civilizations, University of Haifa, Mount Carmel, Haifa 31905, Israel
3The Lobster Conservancy, PO Box 235, Friendship, Maine 04547, USA
4Present address: Israel Oceanographic & Limnological Research Institute, PO Box 8030, Haifa 31080, Israel

ABSTRACT: We compared the antipredator mechanisms of 3 morphological 'types' of lobsters: slipper lobsters Scyllarides latus, spiny lobsters Palinurus elephas and clawed lobsters Homarus gammarus. These lobsters differ in the extent and effectiveness of their weaponry and armor, which we assessed by: (1) field tethering experiments that compared relative survival of intact and manipulated (clinging ability, antennae, or claws removed) lobsters in the face of predation, and (2) measurements of the breaking strength and thickness of the carapace of each species. Intact clawed lobsters suffered higher mortality than either intact slipper or spiny lobsters after both 4 and 24 h. At 24 h, intact spiny lobsters also had higher mortality than intact and manipulated slipper lobsters. The intact spiny and clawed lobsters suffered less predation after 4 h than the manipulated lobsters (lacking weapons); however, this advantage diminished or vanished by 24 h. This indicates that weapons provided some measure of protection in the short-term, which might be sufficient to allow the lobsters to escape from a predator using a strong abdominal tail flip. Triggerfish Balistes carolinensis were the primary predators on the lobsters. We also saw octopuses Octopus vulgaris feeding on lobsters, but these were never observed subduing a live lobster. 'Punch'-tests (i.e. puncture tests) on the carapaces of each of the 3 species showed that slipper lobsters had stronger armor than either spiny or clawed lobsters, while the spiny lobster armor was intermediate in strength. These results suggest that the defensive strong armor of slipper lobsters is a more effective antipredatory mechanism than the offensive morphological weapons of the spiny and clawed lobsters.

KEY WORDS: Predator-prey interactions · Predator-avoidance · Antipredator mechanisms · Weapons · Armor · Lobsters · Scyllarides latus · Palinurus elephas · Homarus gammarus

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