PS 21-200 - Abundance of larvaceans in the northeastern Gulf of Mexico

Background/Question/Methods

Larvaceans, gelatinous tunicates, are the second most abundant zooplankton globally. They are filter feeders that contribute greatly to biogeochemical processes, shedding their particulate-rich cellulose houses to rapidly transport carbon to depths. In addition, larvaceans are prey to economically important fish and found in all oceans. Despite their importance, little is known about larvacean abundance and ecological structure in the Northeastern Gulf of Mexico (NEGOM). This study uses samples collected in the NEGOM between August 2010­­–2014 with the novel Shadowed Image Particle Profiling and Evaluation Recorder (SIPPER), a zooplankton imaging system deployed throughout the water column. Data collected via SIPPER demonstrated that traditional methods of sampling have underrepresented larvacean abundance by 300%.

Results/Conclusions

Preliminary data indicated variability in environmental parameters that influenced larvacean abundance between summer seasons of 2012, 2013 and 2014. Furthermore, there was a significant difference in abundance between summer, spring, and winter of those years. This study aims to determine what environmental conditions govern the seasonal and interannual variability in larvacean abundance, and to quantify their vertical distribution in relation to physical processes, environmental parameters, and potential predators. This study aims to serve as a baseline for larvacean abundance and distribution in the Northeastern Gulf of Mexico.