Tag Archives: mpa

Eric Eisenhardt: Efficacy of bottomfish recovery zones

We have a great op in the San Juan Islands to compare marine reserves set up in ~1990 (mandatory) with bottomfish recovery zones (BRZ) were established ~7 years later (voluntary).  Overall, regulations have changed over time, essentially getting more restrictive.

Methods: 300 dives since 1997; transects to compare recovery zones with paired (nearby) reserve

lingcod length: bigger in reserves (2001-2002), but not significantly differnt in 06-07.  Same results with copper rockfish.

populations declining over this period 01-07, except black rockfish which have increased in population and size.

Why aren’t BRZs working better?

  • Using substrate maps, we can see that BRZs have similar areas to the the reference sites and actually have proportionally more rocky habitat.
  • Fishing effort is pretty even over all (e.g. along the west side of San Juan Island, Pile Point and Lime Kiln are about the same as Eagle Point)
  • Compliance issues may be the problem, or the size of the BRZs may be too small

It’s been 10 years.  What shall we do next?

  • Change nothing
  • One larger BRZ?
  • Make BRZs mandatory
  • Make them larger and mandatory