World Fish Migration Lower Hudson & Harbor Fish Count
Fish Migration!
Each spring the Hudson River is alive with migratory fish species that are drawn from the ocean into the protective waters of the estuary as part of their spawning cycle. Estuaries provide smaller, shallower waterways with protection from the much larger fish that circulate in the ocean, along with a wonderful buffet of foods. Most of our migratory species are anadromous, meaning they live in the ocean and move into estuaries and freshwater systems, like the Hudson, to reproduce. After spawning, most of the young fish spend only months in the Hudson, although some can spend a year or several years here before moving back out to the ocean waters.
The Hudson also includes the migration of a catadromous species, the American eel. Catadromous fish spend most of their lives in freshwater and travel to the ocean to spawn. Fully mature American eels leave the estuary in the fall, heading down in the Saragasso Sea to spawn. The young leaf shaped spawn travel for about a year, floating on the ocean current, before the are carried into the Hudson on the late spring currents, arriving as tiny transparent glass eels.
May 30th, 2026 we celebrated our 10th annual World Fish Migration Event! Over the 10 years of the event a few fish we have found in our nets every year! These include the Atlantic tomcod, also known as the frost fish due to its cold winter spawning. The numbers of this species have been in decline with the warming of the Hudson River water in the last few decades, but early in the season when the water remains cool we still find the young of year in our nets. Other fish netted each year of sampling include American eel, bay anchovy, mummichog, Atlantic silverside, northern pipefish, white perch, bluefish and winter flounder! This year Atlantic Silverside were found in the highest abundance, but over the 10 years no single species has dominated out nets.
Full summary of all the catches over all the years of the event can be found here.
World Fish Migration Day (WFMD) is a global celebration to create awareness about the importance of migratory fish and free-flowing rivers. On World Fish Migration Day, organizations from around the world coordinate their own event around the common theme of: CONNECTING FISH, RIVERS AND PEOPLE.
Environmental organizations of the Lower Hudson and Harbor have come together to put on our own family-friendly, free fishing events for the public to engage in the wonders of the Hudson River! Event times vary by site so please check the details below.
Below are the 2026 Fishing Sites!
EACH YEAR WE LOOK FORWARD TO MEMBERS OF THE COMMUNITY JOINING US!
Saturday May 30th, 2026 we had 14 sites host a free public fishing event with visitors joining in to help improve our understanding of both migratory and resident fish that are part of the Hudson Estuary. Data from each site supports a better understanding of the migratory use of the estuary, along with the biodiversity of the lower Hudson.
The full set of data allows to compare species richness and abundance to prior year spring fish counts and those that occur during other times of the year. This World Fish Migration Day event builds on spring public fish count events that were organized from 2015 through 2019 as part of the World Science Festival, and we are thankful that there are so many wonderful partners that connect annually to make this annual event a success! The full set of data are shared as part of our long term collection with each year’s building on prior events!