Change is Here

As of March 2015, the AFS University of Maryland Subunit has new government!  Running opposed, the members voted in:

President: Brian Gallagher
Treasurer: Grey Redding
Secretary: Emily Liljestrand

The members of the new government endeavor to maintain the quality of meetings, outreach, and to continue the traditions of this organization.  They also intend to have a greater online presence and increase the volume of blog posts and news dissemination.

Student Research Profile: Migration in white perch

Student Research Profile

Name: Brian Gallagher

Degree Sought: M.S.

Advisor: Dr. Dave Secor

Brian Gallagher (poorly) holding a large white perch caught this past spring.
At the top of the picture, you can see Dr. Dave Secor's finger.

            For a long time, fisheries scientists thought of migration in fish populations as more or less uniform; that is, fish from the same population will have very similar migration patterns, give or take a few “outliers.” This focus on dominant trends meant that individuals who displayed unusual migratory behavior received very little attention from researchers. In the last few decades, however, more attention has been paid to these outliers as scientists have continually detected the presence of two or more distinct migratory groups within many different fish populations. This type of migratory behavior is termed “partial migration,” and the migratory groups are (usually) called “contingents.”

            My research is looking at a model species of partial migration in fishes, fondly referred to by my advisor as the “rats of the estuary,” the white perch (Morone americana). A heap of previous work done in the tributaries of the Chesapeake Bay consistently detected two contingents of white perch: one which migrated between brackish and freshwater habitat, and one which resided in freshwater for the entirety of its lifespan. Looking into this further, researchers found that the prevalence of each contingent in each year class was related to environmental conditions and that growth during the larval period largely determined whether fish became resident or migratory. Contingents also experienced differences in growth later in life, such that migratory fish grew faster than their resident counterparts, but at the cost of exploiting a more uncertain environment (think of the tortoise and the hare). Finally, characteristics of both contingents were incorporated into an age-structured population model, which showed that having both migratory behaviors present in the population made it more stable over time and more resilient to perturbations.

Electron micrograph of a white perch otolith. At each point (white squares)
an instrument measures the chemistry of the otolith, which can in turn be used
to reconstruct the migratory behavior of individual fish.

            Extending from this impressive foundation, the goal of my thesis work is to validate partial migration in white perch within the Hudson River Estuary. The presence of partial migration in a different system would indicate that this behavior may be a general phenomenon in white perch, and perhaps warrants investigation in more species. Using otolith microstructure, otolith chemistry analyses, and a long time series of environmental data, I will be exploring potential causes and consequences of partial migration, with the previous work done in the Chesapeake serving as a baseline. Once I get an idea of how the environment influences migratory behavior, and how the characteristics of the contingents differ, the final goal is to apply a similar model as the one mentioned previously, but include projected regional warming trends to see how the population is likely to respond to climate change in the future.

            Who would have thought those “outliers” could have such a big impact?

Guess Who’s Back? (Back Again…)

Hey everyone! We’ve been out of contact on this blog for quite some time now. Back in September, the AFS Tidewater Subunit at CBL had some new faces take over executive duties; they are Alex Atkinson (President), Andrea Sylvia (Secretary) and Brian Gallagher (Treasurer). Since March, the subunit has met three times, each time discussing a recent paper in fisheries science.

More recently, the subunit helped organize and set up a display at the Bernie Fowler Wade-in on June 8th and the St. Mary’s County Crab Festival on June 14th. At both of these events, we talked to folks about some of the research focuses here at the lab, particularly fish and shellfish in Chesapeake Bay. In addition, the CBL seine survey, which has been run by Dr. Dave Secor’s lab for 15 years now, kicked off in May and will continue every week until October.

We’re hoping to be more active on the blog up in the coming months, and we hope to report back soon with posts detailing the research currently being done by our subunit members. We hope to get one student research summary posted every two weeks, so stay tuned!

Nicole Selected As A 2013 Knauss Felllow

Former president, Nicole Bransome Mehaffie, has been selected for a 2013 Knauss Marine Policy fellowship.  She will serve as the Inaugural Knauss fellow for the Ocean, Coastal and Great Lakes Coordination Team in the Office of Policy Analysis at the U.S. Department of the Interior.  She’ll coordinate ocean, coastal and great lakes policies between Interior’s diverse bureaus including U.S. Fish and Wildlife Service, U.S. Geological Survey, and the National Park Service, to name a few. Her position will support the U.S. Coral Reef Task Force and the National Ocean Council in its implementation of the National Ocean Policy.  Nicole is excited for the unique opportunity to see how the federal government manages fisheries and a diversity of other natural resources.  The fellowship begins February 4, 2013 and runs through January 2014.

Patuxent River Appreciation Day

The University of Maryland subunit had a fun time volunteering at the 35^th annual Patuxent River Appreciation Days in October 6-7^th 2012.  Blue crabs were the highlight of the display put on by the Chesapeake Biological Laboratory.  Visitors of all ages were roped in by a colorful poster, larger-than-life blue crab figurines and a fun game for kids.  As an iconic and delicious part of Maryland culture, it was great to see Maryland natives and visitors alike learn about blue crab biology and their recovering population.  Visitors learned of the migration pattern of blue crabs in Chesapeake Bay and how to distinguish between male and female blue crabs.  Volunteers provided an update on the status of the population after the fishing moratorium on female blue crabs in 2008.  Kids got the chance to “be a crab” by using tongs as claws to fish for their food.  With delicious food, unique vendors, engaging displays and music, P.R.A.D. provided an exciting atmosphere for all ages.  Overall, a great time was had by all at Patuxent River Appreciation Days 2012 and thanks to Debbie Hoffbeck for coordinating our display and taking photos!

 By Alex Atkinson

Alex teaching kids how to "be a crab"  Credit Debbie H