Tuesday March 26, 2024
NOAA Fisheries —
Last fall, I participated in Leg 2 of our Bottom Trawl Survey aboard the NOAA ship Henry B. Bigelow, marking the 60th anniversary of this survey. Leg 2 lasted 3 weeks and I looked forward to a break from the office to reconnect with the fieldwork, the fish, and the fabric of life at sea. As a biologist in the Population Dynamics Branch, I also wanted to refresh my memory and appreciation for the data collection that occurs on the survey, particularly as it relates to stock assessments.
A stock assessment is a critical tool that managers use to identify how many fish can be harvested every year without depleting the population. Conducting an assessment involves estimating past, current, and future stock sizes. To understand the forces at play, scientists often develop mathematical models. Data from our survey are crucial for stock assessments.
During the survey, we sample and collect data at a series of predetermined stations. It starts with the ship crew conducting Conductivity, Temperature, and Depth (CTD) sampling to record water column properties. Some stations are also sampled for plankton and larval fish using a bongo net. This provides habitat characteristics and oceanographic conditions over space and time, which contribute to a greater understanding of the state of the ecosystem and provide useful insight for stock assessments.