Larval fish distributions in relation to diel cycle, bottom water hypoxia, and a thin layer of phytoplankton collected aboard R/V Point Sur cruise PS17_02 (PTS03) in the northern Gulf of Mexico from 2016-07-24 to 2016-07-28

This dataset contains larval fish distributions in relation to the diel cycle, bottom water hypoxia, and a thin layer of phytoplankton collected aboard the R/V Point Sur cruise PS17_02 (PTS03) in the northern Gulf of Mexico from 2016-07-24 to 2016-07-28. As part of the CONCORDE field sampling campaign, we sampled with an In Situ Ichthyoplankton Imaging System (ISIIS) along one transect spanning about 10 km three times during the day and three times during the night. This dataset examines the western-most corridor for abundances of different larval fishes during day and night in summer 2016. Particles above a 2000 pixel size threshold (~3.3 mm equivalent spherical diameter) were automatically extracted and manually identified with the highest taxonomic resolution possible (in many cases, to genus or species level). The ISIIS collected images of plankton along with high-resolution physical oceanographic data, which were merged using the nearest time stamp. Larval fishes were also extracted from a dataset sampling a thin layer in the same location three days prior (July 24, 2016). Larval fishes were identified, the standard length was measured in pixels, which is then converted to mm in the R code (2048 pixels is equal to 120 mm). The dataset also contains dates, longitude and latitudes of sample collection. In addition, measurements of temperature, oxygen content, and salinity were recorded. The goal of the study was to understand the distribution of different larval fish families in relation to the diel cycle, low oxygen conditions, and fine-scale aggregation of plankton, all of which are likely common in the Mississippi Bight during the summer. Other related zooplankton, ichthyoplankton, BIONESS (Bedford Institute of Oceanography Net Environmental Sampling System) profile, and zooplankton net samples data collected during this cruise are available under GRIIDC Unique Dataset Identifiers (UDIs) R4.x260.000:0009 (DOI: 10.7266/n7-0txv-z733) and R4.x260.000.0003 (DOI: 10.7266/N74T6GQD).