Plankton Survey

Plankton and environmental sampling are carried out during dedicated plankton surveys and on other resource surveys (trawl) at predetermined stations arranged in a fixed, systematic grid pattern across the entire Gulf of Mexico. Most but not all stations are located at ~56 km or ? degree intervals along this grid. Sampling is conducted primarily within 0.5 to 1m of the ocean surface and down to a maximum depth 200 m (or to within 2 to 5 m of the bottom) with standard SEAMAP neuston and bongo nets, respectively. Physical oceanographic data (temperature, salinity, fluorescence, oxygen) are collected at each station and chlorophyll measurements are taken at three depths.

The original plan for SEAMAP plankton surveys called for seasonal (quarterly) Gulf-wide surveys over both continental shelf (10-200 m depth) and open ocean waters (>200 m to the EEZ). This goal has never been achieved and, as a result, SEAMAP plankton surveys have yet to encompass the spawning seasons and spawning habitats/areas of all Gulf of Mexico species. The most significant sampling and data deficiencies are open ocean waters in summer, fall and

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winter months; shelf waters during spring; and the west Florida shelf in summer and fall months. The importance of these data deficiencies were obvious when researchers tried to respond to the Deepwater Horizon oil spill.

Data from expanded Gulf-wide monitoring and early life history studies would fill major gaps in our knowledge of fish and invertebrate spawning seasonality and early life histories. The expansion of sample and specimen analyses would fill major data gaps and, in many cases, first ever data on developmental stages, species-specific vital rates (age, growth and mortality) and trophic dynamics. These data, in conjunction with other data collected during current and expanded surveys, would provide a more complete and detailed picture of the Gulf of Mexico ecosystem. Information would be used to develop ecosystem models for the Gulf of Mexico, as well as providing a baseline for any future ecosystem impact assessments.