Table 2. Comparison of krill (Nyctiphanes australis) aggregation depth in the South Taranaki Bight, New Zealand, not within 2 km radius of blue whale (B. m. brevicauda) sightings and those within 2 km of sightings.
The mean dive time of whales at each sighting by group (all, foraging observed, surface lunge feeding observed) are also given.
| Sample size (blue whale sightings/ krill aggregations) | Mean krill depth (m); (SE) | Mean dive time (min) (SE); n = # of dives | |
|---|---|---|---|
| All krill aggregations not at sighting | NA/2019 | 47.31 (±0.71) | NA |
| All sightings | 32/892 | 38.09 (±0.92) | 2.83 (±0.18); n > 248a |
| All foraging sightings | 15/398 | 32.64 (±1.27) | 2.56 (±0.19); n > 137b |
| Sightings with surface lunge feeding observed | 6/122 | 26.42 (±2.01) | 1.77 (±0.07); n = 80 |
Notes.
a
The number of dives monitored to assess mean dive time was not maintained for four out of 32 blue whale sightings, although the mean dive time at all sightings was recorded. Therefore, a minimum sample size of dives monitored (n = 248) is provided.
b
The number of dives monitored to assess mean dive time was not maintained for two out of 15 foraging blue whale sightings, although the mean dive time at all sightings was recorded. Therefore, a minimum sample size of dives monitored (n = 137) at foraging sightings is provided.