Meeting Abstract
Wave forced detachment from a substrate has fitness consequences for Leptasterias spp, a genus of small, brooding sea stars with low dispersal. At low tide, Leptasterias are found in wave-protected (pool) or wave-exposed (rocky) microhabitats. Variation in attachment strength between pool and rock stars could indicate microhabitat selection or a flexible response to environmental stress. We investigate the attachment strength of Leptasterias by quantifying resistance to detachment by measuring the force required to pull a star away from its substrate (a “pull”). A flexible, piano-wire clamp connected to a spring scale is used to minimize interference between the tube-feet and substrate. Pulls were recorded in the field and lab, along with the star’s weight. Rock star field pulls from Pigeon Point (CA) ranged from 73-860 g (n=7), and the combined range for 2 similar WA locations was 300-2500 g (n=9). Dividing the pull force by the weight of the star gives the specific pull-strength (SPS). For rock stars, the SPS ranged from 400 to 1000, with values tightly clustered about 400-600. Wave-protected pool stars from Pigeon Point attached less strongly: 175-450 g (n=8), with SPS in the range 33-210. Larger sample sizes are needed to fully resolve the difference in attachment strength between pool and rocky microhabitats and to address the causes and limits of variation within individuals related to environmental stress. Variation in pool and rock star attachment strength may be useful for monitoring changes in Eastern Pacific coastal communities impacted by increasing physical stress from altered water quality and wave impacts.
