15.8 Wednesday, Jan. 4 Impacts of Hypoxia and Domoic Acid on Large Muscle Activity in the Shrimp Litopenaeus vannamei BURNETT, K*; WISE, R; PETTY, A; FIRE, S; HAYNES, B; WANG, Z; HARDY, K; BURNETT, L; College of Charleston; College of Charleston; College of Charleston; Biotoxins Program, NOAA/NOS; Biotoxins Program, NOAA/NOS; Biotoxins Program, NOAA/NOS; Medical University of South Carolina; College of Charleston firstname.lastname@example.org
Low oxygen (hypoxia=H) slows the rate at which crustaceans can replenish arginine phosphate which powers anaerobic muscle activity. H often follows or coincides with harmful algal blooms. Domoic acid (DA), a toxin produced by the diatom Pseudo-nitzschia, binds to glutamate receptors of the neuromuscular junction in crustacean muscles. We tested whether H and DA, individually or combined, alter anaerobic tail muscle activity and/or recovery from fatigue in L. vannamei. Muscle activity (initial tail-flips to fatigue) was not significantly altered by H (O2=4.0 kPa, CO2<0.06 kPa) vs. air-saturated water (normoxia=N). However, fatigued animals that recovered for 10 min in H performed fewer tail-flips than controls recovered in N (H=9.0±3.8 SEM; N=17.4±3.8, P<0.001). In a second study, shrimp immersed for 30 min in seawater (SW) or SW with 400 ug DA L-1 were transferred to H or N and tested for anaerobic muscle activity and recovery from fatigue. As before, H reduced recovery tail-flips (2W-ANOVA, P=0.034). In contrast, DA reduced initial tail-flips to fatigue (2W-ANOVA, P=0.006). Thus, shrimp exposed to DA and H performed fewer initial tail-flips to fatigue (DA/H=24.6±2.7 SEM; SW/N=33.3±3.8) and after recovery (DA/H=13.6±1.5; SW/N=20.0±1.6). DA and H show independent and additive effects on anaerobic muscle activity in crustaceans. If predator avoidance is similarly impaired, then crustaceans may be vectors of DA to higher trophic orders in the marine food web (NOAA OHH at HML; NSF DBI-1062990, IOS-0725245).