Zooplankton in neritic and oceanic waters in the Western Gulf of Mexico

The biomass of 14 zooplankton groups collected from the neritic and oceanic waters of the western Gulf of Mexico is presented. The zooplankton samples were part of the project “Environmental framework of oceanographic conditions in the northwest sector of the Exclusive Economic Zone of Mexico in the Gulf of Mexico,” and were collected during July 2010, January 2011, and October-November 2012. A total of 83 stations were sampled using a Bongo net with a mesh opening of 333 μm. A flowmeter was placed on each net to estimate the volume of the filtered water. The samples were fixed with formaldehyde (4%) and neutralized with sodium borate. Each sample was processed using a Folsom plankton splitter in the laboratory. The main zooplankton groups were identified in each fraction. The biomass of each group was expressed as the displaced volume. (mL/100 m3). Fourteen groups of zooplankton belonging to six phyla were identified. The zooplankton community was represented by 14 main groups (amphipods, copepods, decapod larvae, megalopa, stomatopod larvae, fish larvae, luciferids, jellyfish, mollusks, ostracods, polychaetes, chaetognaths, salps, and siphonophores). All groups were present in the three periods analyzed and most of them were very abundant in July, among which the chaetognaths, copepods, and luciferids were the most prominent.