Blog | The 5 W’s of the Sentinel Survey

The Sentinel Survey is just one part of Maine Center for Coastal Fisheries’ (MCCF) methodical approach to groundfish research and policy over the past 14 years. At MCCF, we use local knowledge to create conditions for groundfish stocks to recover, while also working to regain access rights for local fishermen.

Who works on the survey?

Lead researcher for the Sentinel Survey, graduate student Mattie Rodrigue

The Sentinel Survey is conducted by Maine Center for Coastal Fisheries, in collaboration with the University of Maine. Spearheading the survey is University of Maine graduate student, Mattie Rodrigue. In addition to Rodrigue, groundfish samples are also collected by graduate student John Carlucci, and two fishermen, Mattie Thomson of Monhegan and Steve Brown of Cherryfield, captain the vessels from which the research is conducted. Numerous fishermen have worked on the survey over the years, from Tenant’s Harbor to Jonesport.

What are you sampling?

Data is collected on more than 20 groundfish species, most notably cod, halibut, mackerel, cusk, haddock, pollock, and hake. In addition to gathering abundance and distribution information for each species, the original purpose of the survey, data on the specific biological breakdown of each species has increased in recent years. Thanks to biological data, a single fish can help paint a picture of where that species has been and what it has been doing.

Examples of biological samples collected are:

Gonads: tell us about reproductive maturity and whether a fish is pre- or post-spawn

Stomach contents: tell us what a fish is eating

Otoliths: or ear bones, tell us how old a fish is

Fin clips: genetic analysis identifies what stock or sub stock population the fish belongs to

Muscle tissue: tells us about diet patterns

Photographs: used for morphometric studies


When does the survey take place?

Data collected during the Sentinel Survey is distributed to partners both domestically and internationally

Data is collected and processed from June to October. Maine Center for Coastal Fisheries’ permit to fish during the summer season is unique for the region and results in a data source that is highly sought after.

Biological data collected supports a variety of ongoing research efforts beyond Maine Center for Coastal Fisheries. MCCF has led a highly collaborative effort to distribute groundfish data up and down the coast, from Massachusetts all the way into Canada. Partner institutes include the University of Maine, the University of New Hampshire, Gulf of Maine Research Institute, Woods Hole Oceanographic Institute, Massachusetts Division of Marine Fisheries, and Fisheries and Oceans Canada (DFO).

Where is data collected?

During a single sampling year, fishermen visit a total of 84 survey stations throughout Eastern Maine. The survey uses longline and jig hook gear to gather samples in areas that trawling sampling methods cannot adequately cover due to rocky bottoms and the prevalence of lobster traps. The survey follows a traditional fisheries-independent survey design, where stations are randomly selected each year and divided across depth ranges called strata. Additionally, there is a component where we ask fishermen to select their own stations based on their knowledge of fishing areas within Eastern Maine.

Fisherman Steve Brown and graduate student John Carlucci steam to a survey station on day one of the 2017 Sentinel Survey season

Why do you participate in the Sentinel Survey?

For generations, the groundfish industry was a fundamental component of Maine’s diverse and thriving fishing economy. However, in the mid-90s, groundfish populations collapsed in the eastern Gulf of Maine. With fishermen no longer fishing for these species, knowledge of the groundfish populations also came to a halt. The Sentinel Survey ensures the monitoring of these various species in Eastern Maine continues – providing a baseline to measure change against. And if, or when, the stock rebuilds, we will be better positioned to sustainably manage the fishery.

The data collected in Eastern Maine can also supplement state and federal assessments, as it provides data in an extremely data-limited region.

Learn more about our work with groundfish here.