Behavioral responses to variable predation risk in the California spiny lobster Panulirus interruptus

Abstract

Shelter dwelling and gregariousness are behavioral strategies used by benthic marine organisms to reduce the risk of predator-induced mortality. For spiny lobsters, the relative and synergistic success of shelter dwelling and aggregation in reducing mortality may vary with the perceived risk of predation as well as the availability and size distribution of conspecifics and shelters. We tested how these factors influence antipredator behavior in the California spiny lobster Panulirus interruptus in southern California kelp forests. We measured shelter and lobster characteristics, predator density, relative lobster mortality outside of shelter, and quantified lobster antipredator behaviors in (1) the La Jolla Ecological Reserve (LJER), a marine protected area with high densities of large fishes known to be lobster predators, and (2) the Point Loma kelp forest, a nearby, heavily fished area. Predator densities and the relative mortality of tethered juvenile and adult lobsters were much higher in the LJER than in Point Loma, as was mean lobster size. In response to higher predation risk, solitary lobsters in the LJER used shelters more closely scaled to their body size than lobsters in Point Loma, thereby restricting predator access to shelters. In addition, aggregations of 2 or more lobsters were more frequent than expected by chance in the LJER, but not in Point Loma. Lobsters in Point Loma commonly were found outside of shelter during the day, whereas no lobsters ever were observed outside of shelter during daylight hours in the LJER. Overall, our results indicate that California spiny lobsters modify their antipredatory behaviors with level of predation risk and that behaviors designed to minimize predator-induced mortality are similar between California spiny lobsters and other spiny lobster species. KEY WORDS: Spiny lobster · Predation · Shelter · Behavior · Panulirus interruptus · Tethering Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 420: [135][136][137][138][139][140][141][142][143][144] 2010 reducing prey mortality will vary with availability and size distribution of conspecifics and the availability and size-distribution of shelters (Eggleston et al. 1990, Berger & Butler 2001. However, the risk of predation seldom is consistent temporally and spatially, and prey therefore may alter their behavior depending on their perceived predation risk. For example, an organism's perceived risk of predation may change with body size if predators are incapable of preying upon larger individuals (Ryer 1988, Orth & van Montfrans 2002. In Bahia de la Ascension, Mexico, solitary Caribbean spiny lobsters chose to inhabit smaller shelters scaled to their body size under conditions of high predation risk and low conspecific density, and chose to inhabit larger shelters that allowed aggregation under conditions of low predation risk and high conspecific density (Eggleston & Lipcius 1992). Shelter-dwelling organisms that are vulnerable to predators, such as lobste...

Interactive effects of predator and prey harvest on ecological resilience of rocky reefs

“…, Levin and Lubchenco ), which our sub‐web model ignores at all three trophic levels. One potentially key missing species from our model is California sheephead, which prey on both urchins (Cowen ) and lobsters (Loflen and Hovel ). While sheephead and other fish predators likely have lower handling times and higher attack rates on urchin prey (R. P. Dunn, personal observation ), these parameter changes do not qualitatively alter the baseline dynamics produced (Appendix : Fig.…”

No evidence of nonlinear effects of predator density, refuge availability, or body size of prey on prey mortality rates

“…Refuge availability has been shown in other systems to decrease the mortality of prey (Alexander et al., ; Anderson, ; Savino & Stein, ). Typically, increased predation risk leads to an increased use of refuge (Loflen & Hovel, ). As predator density increased, we predicted increased use of refuge by the prey, and consequent decreased prey mortality per predator (Forrester & Steele, ).…”

“…Third, prey exhibit a wide range of antipredator behaviors in response to changes in predator density (Preisser, Orrock, & Oswald, 2007;Smith & Belk, 2001;Stier et al, 2013;Willems & Hill, 2009). Thus, individual level responses by prey may not translate into population level differences in mortality rate because of adjustments in predator foraging time (Loflen & Hovel, 2010) or tradeoffs in prey between feeding and refuging behaviors (Gilliam & Fraser, 1987;Stankowich & Blumstein, 2005).…”

Shifts in attack behavior of an important kelp forest predator within marine reserves

“…Nonetheless, it is unlikely that such changes accounted for the differences in lobster behavior that we observed. Large predatory fish such as giant sea bass Stereolepis gigas are universally rare in southern California, and other species that potentially feed on lobsters such as the California sheephead Semicossyphus pulcher and kelp bass Paralabrax clathratus tend to be larger and more abundant inside reserves (Tetreault & Ambrose 2007, Loflen & Hovel 2010. Higher densities and larger sizes of these potential predators inside reserves should, if anything, have made reserve lobsters more skittish and less likely to attack the sea hares presented by divers.…”