Monday, December 17, 2012

Big News for a Little Keystone Species!

Young menhadenThe Chesapeake Bay’s menhaden (Brevoortia tyrannus) (photo from NOAA, 2012) scored a big victory last week, when the Atlantic States Marine Fisheries Commission (ASMFC) voted to reduce the catch of Atlantic menhaden by 20% per year.  The goal is to reduce overfishing of this important species and leave more individuals to mature to year three, when they’ll be ready to reproduce.  Menhaden are a small, oily fish historically used for bait.  Recently, though, menhaden fishing has become a big industry, supplying fish for the booming Omega 3 fatty acid market.  Menhaden are currently fished using spotter planes and huge purse seine nets (the recreational bait fishery also uses cast nets); populations are now only about 8% of their all-time population highs. 

Menhaden are important, because they’re what scientists call a “keystone species.” A keystone species is a species that has a disproportionate impact on its ecosystem, relative to its biomass; like a keystone in an archway, if the keystone species is removed, the arch, or ecosystem, will collapse.  Keystone species include the sea otter population in the Pacific, desert tortoises in the western U.S., and even prairie dogs (many species depend on their burrows for shelter and hunting).  Removal of menhaden will impact species up and down the food chain and will remove a critical link in the ecosystem. Menhaden sit at the center of the Chesapeake Bay food web.  They are a filter feeder, feeding on zooplanton and phytoplankton, and they’re a vital food source for rockfish, weakfish, bluefish, and predatory birds such as osprey.  Without healthy populations of menhaden, ecosystems will suffer, as will the fisheries that depend on these healthy ecosystems.

So score one for the menhaden!  Now it’s time for the Virginia General Assembly to approve the new catch limits.  VA legislatures need to hear from greenmomsters and dads who would like to protect this valuable resource and ensure a healthy Chesapeake Bay for future generations!   Don’t know who your representative is?  Check out the VA General Assembly website.


Chesapeake Bay Foundation.  2012.  “Atlantic States Take Action to Protect ‘The Most Important Fish in the Sea’ “  Chesapeake Bay Foundation, Bay Daily Website.  Accessed 12/17/12.

Maryland Sea Grant.  2011.  “The Case for Fishing Menhaden.”  Chesapeake Quarterly.  October 2011.  Accessed online 12/17/12.

NOAA Chesapeake Bay Office.  2012.  “Menhaden"  NOAA website, January 2012.  Accessed 12/17/12.

No comments:

Post a Comment