Peer-Reviewed Journal Details
Mandatory Fields
Davenport, J., McCullough, S., Thomas, R., Harman, L., McAllen, R.
Marine Biodiversity Records
Nassarid Whelks hitch-hiking on an edible crab: phoresis, commensalism or fouling?
Optional Fields
The behavioural responses of scavenging animals to mackerel (Scomber scombrus) baits were studied by short-term video photography in shallow water (1618 m depth) at Lough Hyne, Ireland. Earliest arrivals (after seconds/minutes) at baits were small fish or swimming crabs (Liocarcinus depurator), followed by crawling portunid crabs. After tens of minutes, juvenile whelks 24 mm shell length (Nassarius reticulatus and/or Nassarius incrassatus) sometimes arrived to feed. They moved at a mean speed of 1.24 (SD 0.392) mm s21. After tens of minutes or hours, single large scavengers arrived, consuming most of the bait; the most common of these were Cancer pagurus that fed in a wasteful fashion, generating large quantities of mackerel scraps. Cancer pagurus moved into view at a mean speed of 48.7 (SD 16.9) mm s21(39 times the whelk speed). A single individual of C. pagurus (197 mm carapace width) arrived at a bait carrying 24 juvenile whelks on the dorsal surface of its carapace. No whelks were present on walking legs or chelipeds. The crab fed for 6.8 min and 3 whelks fell off before it departed. The nature of this crab/whelk association is discussed; on balance it appears that it is a previously unreported example of phoresy/phoresis. No whelks were observed being carried by other edible crabs or upon large numbers of scavenging portunid crabs.
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