Burrows protect postlarval lobsters Homarus americanus from predation by the non-burrowing cunner Tautogolabrus adspersus, but not from the burrowing mud crab Neopanope texani

Abstract

Groups of 10 late Stage IV or early Stage V lobsters Hornarus arnericanus were introduced into seawater table sections consisting of either a bare sand substrate or a rocky substrate from a subtidal area with some rocks covered by Fucus spp. The lobsters were given 2 d in which to build burrows or depressions. Predators were then introduced into all sections, except those which had been designated as predator-free, sand control tanks. These latter tanks served as an estimate of the natural mortality of the lobsters without predation. After 8 d, or after all of the lobsters in a section were consumed, the predators were removed and the number of surviving lobsters was counted and compared to the number surviving In the predator-free control tanks. When subject to predation by non-burrowing fish Tautogolabrus adspersus, more lobsters survived in the rocky substrate than in the sand substrates. However, when burrowing mud crabs Neopanope texani were used as the predator, no significant difference was apparent between the number of lobsters surviving in the rocky and the sand substrates, although significant differences were found between the rocks and controls and the sand and controls. Thus predation occurred in both substrates with the crab predators, indicating that lobsters burrowed under rocks are not protected from burrowing predators. Natural mortality without predation was low during the entire group of experiments.