Tag Archives: seal

John Calambokidis PSGB’09 talk

Changes in marine mammal populations of the Salish Sea: What will the future look like?

Pinnipeds

  • Harbor seal populations have stabilized — probably at historical levels –  in all areas of Washington after rising from lows of the 70s and 80s, often generating (old) conflicts with human fishers…
  • Many haulout areas were actually dynamited, so artificial areas are often used.
  • CA and northern sea lions: Conflicts at Ballard Locks and more recently at Bonneville dam due to human-made structures that were meant to help (not concentrate for predators) threatened fish species

Cetaceans:

  • Grey whales: abundance about 20k up from ~10k in ~1970; seasonal resident whales have been in conflict; ’99-2000 mortality/stranding events was prey-related, but there are ship-strike issues and entanglement questions
  • Fin whales: 2002 four were struck/found in Salish Sea (probably hit on outer coast)
  • Harbor porpoise: common in PS prior to 1950s; virtually eliminated; on the rise; 2007 three strandings with evidence of entanglement.
  • Humpbacks: dramatic recovery off US west coast 600 in early 1990s, to 1500 now, increasing at 7.5%/yr; used to be whaled in BC, but now we’re getting sighting in inland sea; SPLASH (’04-’07) showed extreme site fidelity, North Pac pop estimate of ~20k.  Since 1990 prey has switched from krill to fish, partially because of more coastal habitat use.
  • Blue whale: Jan 2009 first confirmed sighting in 50yrs.

What will future look like?

  • Protection does work: PCB ban reduced levels in seals; ESA listing has helped many populations, e.g. greys
  • Challenges remain: emerging contaminants; conflicts with fisheries (KW-Chinook link); vessel traffic and development
  • Many populations could reach carrying capacity like the seals
  • Conflicts with shipping, development…