Unsupported Browser Detected

Internet Explorer lacks support for the features of this website. For the best experience, please use a modern browser such as Chrome, Firefox, or Edge.

Data Collection Mile after Mile, Year after Year

September 06, 2022

The need for reliable and consistent data to support stock assessments highlights the importance of conducting the bottom longline survey annually for sharks and reef fish.

Eric Hoffmayer from SEFSC tagging sandbar shark.JPG Eric Hoffmayer is measuring a sandbar shark on the cradle. The data collected from each retrieval is vital for multiple purposes, such as describing the age structure of the sampled population, size at maturity, and life stage specific distribution patterns, among many other uses. Credit: NOAA Fisheries/ Ellie Hartman

Sometimes we’re asked why we need to do these surveys every year—wondering if the information really changes that quickly. Having long-term, consistently gathered data allows scientists and resource managers to identify trends and anomalies for a species. The better we can interpret the data, the more reliable our management actions will be. 

Long-Term Data Sets for Shark Species

“This is a unique survey because it provides us with scientific data on sharks over a very broad spatial and depth range,” said Walter Ingram, Ph.D., NOAA’s Southeast Fisheries Science Center research fisheries biologist. 

James Rhue and Christian Jones tag, measure, and collect data from a scalloped hammerhead shark.
James Rhue (left) and Christian Jones (right) bring a scalloped hammerhead up in the cradle, aboard NOAA Ship Oregon II, to measure, tag, and collect biological samples from the shark before returning it to the ocean. Credit: NOAA Fisheries/ Ellie Hartman

This bottom longline survey has completed nearly three decades of research—it has gathered a lot of information. This is critical to many species because we can understand how different populations have fluctuated over multiple years. Also we can look at their migratory patterns and temperature-related depth distributions to see if changes have occurred over time. 

Christian Jones tags, measures, and collects data on a scalloped hammerhead
Christian Jones has been assisting in the collection of bottom longline survey data for almost twenty years. As one of the field party chiefs, he works to ensure that the team collects the data needed to properly assess these species. Here, he is preparing to collect information on a scalloped hammerhead. Credit: NOAA Office of Marine and Aviation Operations/ Ensign Justin Weeks

For instance, a few scientists from the survey are noticing an increasing trend in sandbar shark abundance in the southeast region. Eric Hoffmayer, Ph.D, a research fisheries biologist with NOAA's Southeast Fisheries Science Center, explained, “In 2008, the sandbar shark population was considered overfished, so there were restrictions instituted on sandbar shark capture in recreational and commercial fisheries. Thanks to those regulations, we’ve seen an increase in the annual number of sandbar sharks caught on this survey.”

Our team of scientists use other tools, such as tags, to collect movement and habitat utilization pattern data on sharks. The tags can provide valuable information that can be compiled for long-term analysis. We use two types: dart tags and satellite tags. The satellite tags are not used on every shark, but there are certain species of interest where they are used to fill data gaps. For example, Dr. Hoffmayer stated, “Our current interest is the habitat use patterns of great hammerheads in the Gulf of Mexico because of the lack of information on their movements and migratory patterns in this region.”

Assessing Reef Fish Populations 

On the bottom longline survey, we also collect data on several commercially and recreationally important species of grouper, snapper, and tilefish. Many of these reef fish populations have endured overfishing. “Several reef fish species that we catch on this survey are considered high priority, so we need to collect relative abundance data annually,” reiterated Dr. Hoffmayer. This annual survey informs stock assessments and is critical to the sustainability of these fisheries.

Bringing in a grouper for reef fish research on bottom longline survey
Sustainable fisheries management relies on fisheries-independent and dependent data collection. Glenn Knot and Jacob Gonzalez pictured. Credit: NOAA Fisheries/ Ellie Hartman

The red snapper is a primary focus for this survey,” explains Christian Jones, Ph.D., a research fisheries biologist at NOAA's Southeast Fisheries Science Center. “We also want to collect as much data as we can for all of the species we encounter because it is important for stock assessment and ecosystem management.”

Both the reef fish and sharks we see on this survey play an important ecological and economic role in the region. Having data about these species that is consistently collected on an annual basis, over a long period of time, ensures that resource managers have the information they need to best manage these populations. Without this data from the survey, there would be gaps in information needed for accurate and informed stock assessments that promote a healthy ecosystem. 

Meet the Blogger

A smiling young woman holding a camera

Ellie Hartman

Ellie Hartman was born and raised in Breckenridge, Colorado. She was a communications intern, research assistant, and marine mammal observer for NOAA's Southeast Science Center. She graduated from Barry University with a Master's of Business Administration and graduated from University of Miami with a Master's of Professional Science in Marine Conservation. Meet Ellie


Previous: Sharks, Snapper, and Science—Kicking off the 27th Year of the Southeast Bottom Longline Survey Next: Being a NOAA Fisherman on the Bottom Longline Survey

Last updated by Southeast Fisheries Science Center on March 11, 2024