Written & Edited by Rachel Pichette

Posted by Ricardo Serrano

One of the students whose excellent work we are spotlighting this week is Nicholas Calabrese, a Ph.D. student studying living marine resource management. Calabrese is from Wilbraham, Massachusetts, and received his bachelor’s degree in Marine Biology from Roger Williams University. He then pursued an MS in living marine resource management from the UMass Dartmouth – School for Marine Science and Technology.

Calabrese’s research focuses on the Gulf of Maine Atlantic cod fishery. When pursuing his master’s degree he helped to develop the SMAST video trawl, which was used to survey Atlantic cod in the Gulf of Maine. The net is open with a camera to count fish as they pass through it. The count is taken without capturing or killing the fish sampled.

In order to set catch limits on commercial fishing, scientists need a close estimate of fish populations. Fishery surveys are crucial to this endeavor.  However, when surveying fish the net cannot catch all of the fish in a given area. Some fish escape, while others are not sampled to begin with. For his Ph.D. Calabrese is working to design new technology to help determine the catchability of Atlantic Cod. Calabrese states, “Catchability is the parameter that allows you to scale your catch to the population in the area. To estimate this, we need to have a separate estimate of the population in the surveyed area, and because fish move these estimates need to be made simultaneously. Using this estimate and our catch we can calculate catchability.” 


In order to estimate population size, he will be performing a mark-recapture experiment. In regards to this, Calabrese says, “In these experiments, a large number of fish are caught and tagged, then the area is fished again. The ratio of untagged to tagged fish in the second sample allows you to calculate population size. The novel part of my project is the method with which we will be conducting this experiment. Since we fish the video trawl survey with an open net we won’t have the fish on deck to check for tags. Instead, we developed a passive integrated transponder (PIT) tag reading system that can be placed in the net. The fish are tagged with a PIT tag which operates in a similar manner to the RFID chip in your UMass Pass. The antennae in the net will scan any PIT tags as they pass through and record their unique ID number.”

Why is this work important to you and to the larger community?

Gulf of Maine Atlantic cod is one of the oldest fisheries in North America, and it is what I grew up fishing for. In the past decade or so there has been a dramatic decline in their population, and the recreational fishery I used to enjoy has been closed entirely. It has been hard to identify the exact cause, but I wanted to be part of the solution. The first step in that direction is getting a better idea of how many fish are actually out there.”

What is the most challenging aspect of your research?

Calabrese: “Field-work in the marine environment is always challenging. The saltwater takes a toll on electronics and developing new systems is always a trial and error process. This is compounded by the fact that we typically perform two to three surveys a year. When issues arise there is typically no way to quickly repeat an experiment. In order to complete an experiment not only does all the equipment need to function properly, but the weather and the fish need to cooperate. If we don’t find any fish we can’t tag anything.”

What part of your research are you most proud of?

Calabrese: “I think I am most proud of the technology we have been able to design and build ourselves. From the video itself to the PIT tag readers, we have had to become our own engineers, and have done so successfully. Though not on the first try.”

What long-term goals do you have for your work?

Calabrese: “Our long term goal is to expand our survey technique into one that is used across the entire stock area to produce data that can be used in stock assessment. After I graduate I would like to continue working on fisheries independent surveys, with the hopes of eventually becoming a professor.”

When Calabrese is not at sea for work, he spends his free time on the water fishing for fun.  He plans to graduate with his Ph.D. in 2022.  You can follow Nick and his work on Facebook and Instagram on his personal accounts or at the SMAST lab.

Nicholas Calabrese Social: 

Facebook: https://www.facebook.com/nicholas.calabrese.5

Instagram:  @ncalabrese285

Lab Facebook: https://www.facebook.com/fisheriesfieldresearch

Lab Instagram: @marinefisheries_smast

You can also check out academic papers Nick has contributed to below:

Kevin D.E. Stokesbury, Nicholas M. Calabrese, and Travis M. Lowery (2019) Windowpane Flounder seasonal distribution and survey availability on the southern portion of Georges Bank, USA, Marine and Coastal Fisheries, 11, 353-361.

Nicholas M. Calabrese. A Video Trawl Survey for Atlantic Cod (Gadus morhua) in New England. Master’s Thesis. University of Massachusetts Dartmouth School for Marine Science and Technology, Fairhaven, MA.

Kevin D. E. Stokesbury, Steven X. Cadrin, Nicholas Calabrese, Emily Keiley, Travis Lowery, Brian J. Rothschild, Gregory R DeCelles Towards a New Sampling System for Surveying New England Groundfish Using Video Technology, Fisheries, 42:8, 432-439.

David L. Taylor, Nicholas M. Calabrese (2018) Mercury content of blue crabs (Callinectes sapidus) from southern New England coastal habitats: Contamination in an emergent fishery and risks to human consumers, Marine Pollution Bulletin 126, 166-178.

Gregory R. DeCelles, Emily F. Keiley, Travis M. Lowery, Nicholas M. Calabrese & Kevin D. E. Stokesbury (2017) Development of a Video Trawl Survey System for New England Groundfish, Transactions of the American Fisheries Society, 146:3, 462-477