Location: Gulf of Mexico Estuary near Port Aransas, Texas. FAML: pier at in Corpus Christi Channel, Port Aransas, TX, United States, Fisheries and Mariculture Laboratory of the University of Texas Marine Science Institute (lat. 27.8396111, lon. -97.0827222); MI: Mud Island in Aransas Bay, TX, United States (lat. 27.9362222, lon. -97.0217777)).

Methods & Sampling

Total lipids were measured for samples of marine animals and fish eggs collected from the field. Plankton net (500-µm mesh) samples were sorted immediately after collection (live material).  Samples of jellyfish were collected using dip net. Animals were transferred to holding tanks to evacuate their guts for 4-5 hours. Fish were collected using cast net and seines. Fishes were immediately euthanized with lethal dose of MS-222. The euthanized fish were placed on ice and liver was collected. Each sample was rinsed twice in distilled water and frozen at -80°C for subsequent analysis. The time between collection and analysis ranged from 2 months to a year.

For total lipids, each sample was lyophilized, homogenized, and weighed. Total lipid was measured by the phosphosulphovanillin method (Barnes and Blackstock, 1973). Briefly, lipids were cold extracted from lyophilized and homogenized samples with 2:1 chloroform: methanol (v/v). A calibration curve was prepared by performing 1:2 serial dilutions on a cholesterol standard (Millipore-Sigma, Burlington, MA, USA) dissolved in 2:1 chloroform:methanol (v/v). Blank, standards, and extracted lipid samples were reacted with concentrated sulphuric acid and vanillin (vanillin in 4:1 85% phosphoric acid: water v/v) and were run in duplicate. Absorbance was measured using a Spectramax 190 Microplate Reader (Molecular Devices, San Jose, CA, USA) at a wavelength of 520 nm. Total lipids were expressed as mg g−1 dry weight.