Decision points: experimental protocol

9 Tagging

We will tag as many animals per tagging period as is practical. Whether we decide to stop tagging after a tag-on depends mainly on 1) the quality of the attachment, and 2) our ability to track the animal(s).

* the experiment will stop 5 minutes after reaching full power. The 1 hr is what the model assumed when assessing the reduction in risk.

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How long post-tagging before start approach? What is the logic?

• if DTag 3 GPS not available, GPS tags + DTag would be useful (critical?) for tagging multiple animals, given that tracking boat is untested.

• Use 1 hrs principle for post-tagging if multiple individuals can be tracked.

• Probably long pre-exposure good to characterize movement.

• Post-exposure less critical in ramp-up experiment?

CPA estimation

The times tRU and tFP are based on the estimated closest point of approach (CPA) of the vessel to the whale. Therefore, the CPA has to be known before tRU is reached. As the CPA will depend on the sightings of the whale, we will determine the CPA while we are approaching the animal (as we have been doing during regular 3S experiments).

The predictability of the movements of the tagged animal is important to get a reliable CPA. We can decide to base the method of CPA estimation on the behavioral state of the animal, or decide to only start an experiment when animals are showing (or not showing) a certain type of behavior. For instance, when animals are feeding on one location (e.g.

while bubble-net feeding), the last sighting of the whale before tRU can be used as CPA.

When animals are travelling between feeding areas, or migrating, and are on a very directional path, it could be most useful to estimate CPA from the speed and heading of the whale. We are also likely to encounter whales that forage on euphausiids (Stevick, 2006). Because such animals may show more ‘patchy’ feeding behavior, it may be necessary to break off approaches or make extra turns before starting the final pass.

• we need a tool to predict the future position of the whale based on previous sightings.

• in both runs (no-ramp up/ramp-up) full power starts at this CPA position at tFP.

• The position of the whale is estimated by extrapolating the last whale sightings forward in time to tFP.

• The CPA = 0 m position is estimated as the most-likely location of the whale at start of full power tFP. Due to the uncertainties in whale movement, it is unlikely that the whale will be at exactly that location, but will optimize the proximity to the whale at tFP.

• at tRU minutes the ship heading is fixed toward the location where it is expected that CPA will be obtained at tFP.

•

collision and sonar mitigation procedures should be in place for the case when the source closely approaches the whale by R < Rmit.

•

the no ramp-up approach will not be performed in the first year (or only at the end?). The results from the ramp-up experiment from the first year will be used to assess the risk of doing the no ramp-up approach.

22 Distance to whale at full power

The ramp-up procedure is designed to reduce the risk of causing injury in nearby animals, thus we want to be fairly close to the whale and approaching it at this point during the

“no ramp-up” pass. We do not want the whale to actually receive levels that can cause injury, however this seems unlikely because the SPL @ 100 m from the source is down to

~174 dB (based on SL=214 dB and 20 log R). At these short distances, it is important to think in terms of distance from the source and not from the ship..

When we consider cumulative SEL to be more important than maximum SPL, it may be worse for the animal to have full power transmission starting before CPA. Another argument to start slightly before is that, because we are moving towards the animal, starting pinging behind the animal (due to uncertainty in whale position) would cause a much lower maximum level. Thus the variation in maximum level received will thus be larger in the full power dataset.

9 Angle of approach

As before in 3S, our goal is to approach the subject animal head on because then avoidance behavior is the most clear. Because the direction of movement of foraging humpbacks may be less predictable, we do not consider approaching head on to be an absolute requirement.

9 Whale swim speed

For travelling humpback whales, the reported mean horizontal speed is typically between 3 and 5 km/h (0.83 – 1.39 m/s). For example, 4 km/h for non-singing humpbacks

migrating along the coast of Australia (Noad & Cato, 2007), 3.6-5.4 km/h for humpbacks migrating along the East coast of South-Africa (Findlay 1994), 2.6-4.0 km/h in the presence of commercial shipping in Alaska (Baker et al 1993), and 3.0 and 4.5 km/h in the absence and presence of whale-watching vessels off the coast of Ecuador (Scheidat et al., 2004).

We will use a swim speed of 1 m/s in the ramp-up modelling work and for other initial calculations, but this value will be updated based upon our data collection in 2011.

9 Surface-active behavior

Humpback whales are famous for their surface-active behaviors (e.g., Stamation et al 2010 for a list). Some of these may be related to vessel presence, sound exposure, annoyance, etc. The observer protocols will be updated to include surface-active behaviors that are specific for humpbacks.

Dual tow

The Captas or Delphinus array may provide useful information on the whale location or potential vocal responses, but also may limit maneuverability and our ability to work in shallow water (array needs to be below the source).

Duration of full power transmission

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We maintain a 5 min rule (stop transmission 5 min after passing the animal).

Collision safety procedure t.b.d.

In document 11-01289 (sider 159-162)