California spiny lobster (Panulirus interruptus) movement behaviour and habitat use: implications for the effectiveness of marine protected areas

Abstract

The effectiveness of conservation efforts, including marine protected areas (MPAs), hinges on adequate knowledge of movement patterns, habitat associations and habitat-specific survival rates of mobile organisms. California spiny lobsters (Panulirus interruptus) support commercial and recreational fishing in southern California; however, we lack basic information to determine whether MPAs planned for the region will enhance abundance. Working within and outside a small southern California MPA, we (1) quantified the movement patterns and home ranges of the lobster over two time scales, (2) determined lobster day and night habitat associations and (3) determined habitat-specific predation risk. Lobsters exhibited high site fidelity and small home ranges (geometric mean of 651 m2 and 5912 m2 per week, on the basis of 50% and 95% kernel utilisation distributions, respectively). Lobsters were associated with rocky habitat during the day and with the red algae Plocamium cartilagineum while feeding at night. Relative survival rates of lobsters were high across vegetated and unvegetated habitats at night, and were highest in surfgrass (Phyllopsadix torreyi) habitat during the day. Our results highlight the need to consider how movement patterns vary over short and long time scales, and how habitat use may vary from day to night for nocturnally active species such as lobsters, when planning MPAs.