Tag Archives: acoutics

Vessel interactions/noise talks

14:55 Val Veirs giving Marla’s talk on “Vocal Compensation in SRKWs”

  • Background noise levels had mean of 110.1 DB +/- 4.1; range 98-123dB
  • Call source level: mean of 55.3dB +/-7.4 dB
  • Lombard effect in SRKWs is present; ~1dB increase in S1 call source level for every 1dB increase in ambient noise level
  • ambient noise increases with rising number of vessels <1km away
  • There may be a threshold effect, where call source level doesn’t increase until ambient noise reaches ~105dB

15:20 Giles

  • Began studying orcas at age 18, 21 years ago; 2005 Soundwatch intern; worked in land surveying for 11 years; now working on PhD at UC Davis
  • Goals: map vessels and environmental data (bathy) during focal follow observing group cohesion and activity state
  • Equipment: GPS acts as data logger; 1.5-4 power Hakko scope; rangefiner +/-1m at 200om; eye-safe lasers
  • Emulating Rob Williams study of northern residents
  • What portion of observed boats are staying outside of the 1/4nm no-go voluntary zone?  ~50% of private boats, >90% of whale watch vessels.

15:40 Giles talking for Dawn Noren

  • From 2003-2006, we used two Palm Pilots to collect behavioral data during focal follows.  GPS locations and vessel counts <1km also taken.
  • Prelim results for relationship between vessel numbers and diving parameters and swim speeds: some behavioral parameters (like dive duration or surface duration) show breakpoints, vessel counts at which the relationship changes
  • In some cases, the breakpoint changes or the relationships disappear between years.  Why?
  • Relationships between surface active behaviors (SABs) and point of closest approach (POCA) of vessels (2005-6 data): tail slaps represented 2/3 of all SABs.