Meeting Abstract

28.1  Friday, Jan. 4  Extended starvation resistance and subsequent growth recovery in sea urchin larvae: Implications for lifespan in the plankton YU, P. C.*; MANAHAN, D.T.; University of Southern California; University of Southern California pcy@usc.edu

Food availability has a major influence on growth rates of feeding stages of larvae. Variability in oceanic food availability is well documented but knowledge of how such variability impacts larval survival remains incomplete. We investigated the survivorship and starvation recovery of sea urchin larvae (Lytechinus pictus) in the absence and presence of algal food. Survivorship was >77% in 5 larval families (each started from different parents) held without algae for periods of up to 2 weeks. In unfed larvae, total lipid and protein content declined within 2 weeks to ~50% of the initial egg quantities. Triacylglycerols were utilized by 5 days of development; phospholipids were partially depleted by 18 days without algal food. Unfed larvae maintained low respiration rates through 24 days (i.e., no metabolic depression observed). A small percentage (<5%) of unfed larvae survived for 41 days. Algal food (15,000 cells μl^-1) was introduced after varying periods of deprivation, ranging up to 20 days. Survival was >60% for those larvae initially unfed for ~2 weeks, a survival rate not significantly different (p>0.3) from control larvae fed algae once the first feeding stage was reached (day 3). However, survivorship of larvae decreased dramatically when fed after 18 or more days without food. When fed, larvae that recovered from initial deprivation of food grew and successfully metamorphosed. We conclude that extended periods (~2 weeks) without algal food does not limit subsequent growth recovery and metamorphosis. Defining physiological limits of larval survival and subsequent recovery will aid in modeling and predicting dispersal and recruitment potential under variable food environments.