Young Fish Are Also Moving North, Thanks to Climate Change

Written by on October 5, 2015 in Fish, Marine Life

Several studies have shown that the distribution of adult fish in the Northeast U.S. is changing, but few studies have examined the distribution of young fish. A new study from NOAA Fisheries focused on the early life stages of fish to find out what’s happening.

Pelagic juvenile (top) and larval (bottom two) Haddock (Melanogrammus aeglefinus). Photo credit: Harvey Walsh NEFSC/NOAA.

Pelagic juvenile (top) and larval (bottom two) Haddock (Melanogrammus aeglefinus). Photo credit: Harvey Walsh NEFSC/NOAA.

Most marine fish go through several distinct life stages. They start out as tiny eggs (about 1/20 of an inch in diameter) that float around with ocean currents. They then hatch into larvae that don’t at all resemble the fish they will grow up to be. At this point, most of them still have only limited eyesight and many of them don’t have mouths. Then, weeks to months later, they transition into juveniles that look like small versions of the adults we’re familiar with.

Researchers have long known that the distribution of larvae is determined by a combination of where the adults reproduce and the currents that transport the eggs. To determine how the distribution is changing, researchers from NOAA’s Northeast Fisheries Science Center (NEFSC) compared data collected from 1977 to 1987 with data collected from 1999 to 2008.

They found that “the distribution and timing of the life cycle of many fish species are changing,” lead author and fisheries biologist Harvey Walsh explained in a news release.

The researchers found that larval stages of 43% of species studied experienced changes in distribution and timing. Distribution of the adult stages of 50% of those species also shifted. Most species in adult and larval stages shifted northward, which was to be expected with warming temperatures.

“The consequences of these changes for fisheries management need to be considered, but an important first step is documenting that change is occurring,” Walsh said.

To learn more:

Copyright © 2015 by Marine Science Today, a publication of Marine Science Today LLC.

About the Author

About the Author: Emily Tripp is the Publisher and Editor of She holds marine science and biology degrees from the University of Miami's Rosenstiel School of Marine and Atmospheric Science and a Master of Advanced Studies degree in Marine Biodiversity and Conservation from Scripps Institution of Oceanography. When she's not writing about marine science, she's probably running around outside or playing with her dog. .


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