Cape Cod Seals: Successful Recovery or Overpopulation?

Can the successful return of a population after decades of hunting be a bad thing? It seems the answer depends on your perspective…or your job.

In Alaska, for example, sea otters were successfully reintroduced in 1960 after being nearly wiped out. Now, populations are booming and conservationists are thrilled. Many fishers, however, are not; they say the otters are unnecessary competition for shellfish.

Gray and harbor seals on the beach at Jeremy Point in Wellfleet, Mass.

Gray and harbor seals on the beach at Jeremy Point in Wellfleet, Mass. Photo credit: Meghann Murray, NOAA Fisheries.

Cape Cod is experiencing a similar problem: seal populations, once dwindling, have exploded, sparking debate between fishers, conservationists and beachgoers.

In 1991, researchers counted six seal pups on a particular island. On that same island in 2007, they counted 2,096. Exact overall population numbers aren’t known, but the National Marine Fisheries Service estimates that there are around 15,756 seals. That’s nearly three times what there was in 1999.

At the Outer Cape Seal Symposium last week, scientists, fishermen, captains of seal-watching boats and decision-makers gathered to discuss the issue. They focused on what we do and do not know and what, if anything, can or should be done about it. One of the biggest problems is that there isn’t enough data and the research is underfunded.

In the beginning, it was mostly fishers who complained about increasing seal populations as they competed for the same fish. Now they’re gaining allies as many others have started to worry about the associated increase in great white shark sightings. Sharks have found that this is the new hotspot for dinner, so as seal populations continue to increase, so will shark sightings.

But are those reasons enough to start a seal cull? That is likely to be debated for some time to come, particularly because many researchers say a cull won’t do any good without proper research.

In addition, seals have been federally protected under the Marine Mammal Protection Act since 1972. If the decision is made to thin the population, it will involve changing a federal law which won’t be an easy process. The process would be made more difficult by those who oppose it, like local tour-boat captains who are greatly benefiting from the increase in both seal and shark populations.

We’ll keep you posted as research continues and decisions are made.

To learn more, read some of these articles:

Harbor seals and a few gray seals at Chatham Harbor on Cape Cod, Mass.

Harbor seals and a few gray seals at Chatham Harbor on Cape Cod, Mass. Photo credit: Meghann Murray, NOAA Fisheries.

Copyright © 2013 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. .


If you enjoyed this article, subscribe now to receive more just like it.

Subscribe via RSS Feed Find MST on Instagram Connect with MST on Google Plus

2 Reader Comments

Trackback URL Comments RSS Feed

  1. John Leek says:

    Changing the Federal Marine Mammal Protection Act is not needed. Language is built in to end the “moratorium” on hunting, etc if NOAA will judge a population to have reached its “Optimum Sustainable Population” (out of danger). NOAAA is just reluctant to admit it has happened, in spite of all evidence. The seals did not reproduce this fast. They have found urban beaches are safe places and have left the wild to live among people, because people don’t eat seals. This is tinkering with nature by the Feds, not preservation of a threatened species.

  2. Emily says:

    Thanks for your comment, John. If the population is really as big as it seems, why do you suppose NOAA is so reluctant to say that the seals are out of danger?