DMSP INCREASES SURVIVAL OF LARVAL SABLEFISH Anoplopoma fimbria

Dimethylsulfoniopropionate (DMSP) is released by phytoplankton when grazed by zooplankton. Some planktivorous fishes and birds are able to detect and aggregate around DMSP, which serves as a multitrophic chemical cue enabling predators to find prey. Greenwater (algae + seawater) is used to rear larvae of many marine fish species in captivity. DMSP might be a previously unrecognized benefit of greenwater. Supplementing with DMSP may increase greenwater's efficacy, or may allow other substances (e.g., clay) to replace algae. This study tested whether DMSP affects the growth or survival of larval sablefish (Anoplopoma fimbria). Sablefish is a candidate species for aquaculture, but high mortality during the larval stage is a major bottleneck for successful culture.

Larvae were stocked into 37-L tanks with claywater. Rotifers were fed twice per day, along with low-concentration DMSP (1 nM, n=8 claywater), high-concentration DMSP (100 nM, n=8 claywater), or water (control, n=8 claywater). After one week, we quantified survival and weighed larvae after drying overnight in an oven.  

High-concentration DMSP led to approximately 70% greater relative survival than no-DMSP control (p<0.05). There were no significant growth differences among treatments. Later, in order to get a sense of DMSP levels in the tanks, a single dose of low-concentration DMSP, high-concentration DMSP, or water control was added to study tanks under conditions identical to the rearing study, except no larvae were present (n=3 tanks per treatment). Water samples taken 10 minutes after DMSP or water addition showed DMSP concentrations of 3.4 nM (low-concentration DMSP), 61.6 nM (high-concentration DMSP), and 2.6 nM (water). The DMSP in the water control suggests that DMSP levels in the Puget Sound, from which we pump our seawater, could potentially influence hatchery rearing. We will discuss the potential for using DMSP and clay to rear larval sablefish.