The Seascapes

The Seascapes

Tuesday, November 22, 2011

The “Butterfish Smackdown” I. A Little Background

Butterfish habitat model "hindcast" for October 18, 2010 in the mid-Atlantic Bight.  This model will be used in "nowcast" mode in a field evaluation we will perform with a squid fisherman in December  this year.

We are currently in panic mode preparing for a field test of a habitat model for butterfish we built collaboratively with squid fisherman from Cape May, New Jersey, Narragansett, Rhode Island, and Montauk, New York.  Our “Butterfish Smackdown’s” were meetings held over the past year in which fisherman and scientist competed, in a friendly way, and then collaborated to build the statistical model we are about to test.  Our goal was to develop a statistical model we could couple to near real time ocean observations (MARACOOS) to make a regional scale “nowcasts” of butterfish habitat.  If effective, these “nowcasts” might allow fisherman to reduce catches of butterfish as they fish for squid.  This bycatch problem is hard to solve, because when the animals are offshore during the winter and early spring about 4 of 10 trawl samples containing squid also contain butterfish.

Juvenile butterfish hanging out among the tentacles of lions mane jellyfish

Butterfish (Peprilus triacanthus) are small silvery fish that live in the water column and mostly in the coastal ocean from eastern Newfoundland to Florida and the Gulf of Mexico. In the Northwest Atlantic, they migrate from oversummering areas inshore and to the northeast, to the south and offshore to the edge of the continental shelf in the mid-Atlantic Bight during the late fall.  Butterfish are one of the few marine animals that eat jellyfish and salps (also jelly like organisms), as well as other types of zooplankton. The juveniles also seem use jellyfish to avoid predators by hiding among their tentacles.  If this is the case, they have developed a nearly perfect strategy to overcome the “life-dinner principle”  (1).  The principle states that its good to get your dinner, but its much more important to run for your life if you are about to become somebody else’s dinner.  I.e. growth is good but nothing reduces fitness faster than getting killed and eaten.  Butterfish mature at about a year of age and have an extremely high reproductive rate. Minimum population doubling time is estimated to be about 15 months.

We have been focusing our habitat modeling efforts on butterfish and other species that play central roles in the Mid Atlantic Bight Ecosystem.  Butterfish, along with longfin squid, are prey for many to apex predators in the Bight like tuna’s and are therefor important for the transfer of energy from lower trophic levels to upper trophic levels in the food web (2). We just recently published an article demonstrating that ocean observing systems like MARACOOS are useful for describing the coastal ocean habitats of keystone animals such as butterfish (3)

But we wanted our efforts to extend beyond an article in an obscure academic journal and try too operationalize our science by making a useful tool for marine ecosystem management.   We thought involving fisherman in our current project could improve the accuracy of our models.  Fisherman are, of coarse, great practical marine ecologists.  And it has been particularly fascinating to try to understand the physics and ecology in their insights into the sea and the animals they hunt in it.. all of us who are involved in the project share a deep love for the sea.

Collaborators in “Smackdown's” up to this time have included:

Danny Axelsson, 'H&L Axelsson'
Lars Axelsson, 'H&L Axelsson'
Eleanor Bochenek, Rutgers University
Jason Didden, Mid Atlantic Fisheries Council
Greg DiDomenico, Garden State Seafood
Kyle Goodwin, SeaFreeze LTD
Glenn Goodwin, SeaFreeze LTD
Steven Gray, University of Hawaii
Jimmy Harris,  'Trawler Abracadabra'
John Hoey, NEFSC Cooperative Research
Olaf  Jensen, Rutgers University
Josh Kohut, Rutgers University
John Manderson, NEFSC, Behavioral Ecology
Geir Munson, SeaFreeze LTD
Matt Oliver, University of Delaware
Laura Palamara, Rutgers University
Chris Roebuck, SeaFreeze LTD
Wayne Reichle, Lund's Fisheries, Inc
Joel Sonnen, SeaFreeze LTD

1) Dawkins R, Krebs JR (1979) Arms Races between and within Species. Proceedings of the Royal Society of London Series B, Biological Sciences 205:489-511

2) Link J, Overholtz W, O'Reilly J, Green J, Dow D, Palka D, Legault C, Vitaliano J, Guida V, Fogarty M, Brodziak J, Methratta L, Stockhausen W, Col L, Griswold C (2008) The Northeast U.S. continental shelf Energy Modeling and Analysis exercise (EMAX): Ecological network model development and basic ecosystem metrics. Journal of Marine Systems 74:453-474

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