Anne Beaudreau on lingcod in the San Juan Islands

What are the interacting relationships between rockfish, the lingcod that eat them, and the fishers who take lingcod (and rockfish)?  In reserves we can look at predatory role of lingcod without fishing pressure.  We can also look at differences in lingcod population structure and feeding between non/reserves.

Most samples from central San Juan Channel in rocky habitat.

Body size:

  • non-reserve: 35-80cm, mean ~45cm
  • reserve: quite a few large females, 80-120cm.

Catch rate: in reserves we had many more days when we caught >3 lingcod/hour.

Acoustic telemetry synopsis

  • Limited movement: 8/9 tagged lingcod never left reserve
  • Diet composition: rock fish are 20% of diet in reserves, only 5% in non-reserves (maybe because there are more rockfish in reserves, or maybe larger rockfish in reserves eat more rockfish, or maybe there are habitat differences)
  • Estimated rockfish consumption (modeled): consumption of rockfish in reserves may have been 5x non-reserve, with implications for how to recover rockfish!


  • Pop structure differs between non/reserves
  • diet variations suggest local diffs in fish communities
  • there are unexpected ecological consequences of creating reserves…
  • match scales of research and management (got to get down to pretty small scales!)

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>