Eastern North Pacific
Gray Whale Calf Production Survey
Piedras Blancas Lighthouse, CA
23 March –
Notes from the Field:
Week 10: During the final week, the visual survey team at Piedras Blancas Lighthouse recorded 7 cow/calf pairs, down from 58 the previous week.
Figure 1. Gray whale calf/cow counts by week for 2015 field season.
Notes from the Field continued:
Week 9: Week nine of the northbound gray whale calf survey experienced a late surge with 58 calves recorded in good sighting conditions.
Week 8: Week eight of the shore-based survey of northbound gray whale cows and calves logged 69 calves, bringing the season total to 343.
Week 7: Seventh week of the shore-based survey of northbound gray whale cows and calves logged 127 calves, the highest weekly count to date for this season. Weather was generally quite good; 75 minutes of effort was lost due to a small front passing along the Central California Coast. This week's count brings the season total to 276 calves which puts this count in line with counts from 2012 and 2013, each resulting in total estimates of northbound calves of around 1100 (about 5.5-6% of the estimated size of this population).Sixth week of shore-based survey of northbound gray whales resulted in 62 calves recorded during 42 hours of watch effort. Generally the weather was very good, in spite of losing a full day to fog and wind.
Week 6: Sixth week of shore-based survey of northbound gray whales resulted in 62 calves recorded during 42 hours of watch effort. Generally the weather was very good, in spite of losing a full day to fog and wind.
Week 5: Fifth week of the shore-based survey of northbound gray whale calves produced a count of 48 calves in just over 59 hrs of survey effort in very good to excellent sighting conditions. Sighting rates continue to increase.
Week 4: The fourth week of the survey showed an increase of calves relative to previous weeks: 20 cow/calf pairs were recorded, including a calf that breached.
Week 3: The third week of the survey had some wind and rain that cut down effort and only three cow/calf pairs were seen. This is about normal for this time of the year and next week we expect to see the counts of calves start to increase.
Week 2: The team completed the second week of the survey of northbound gray whale calves on Friday, April 3rd. The team recorded 10 northbound calves and also the first blue whale of the season. The second week was characterized by high winds that cost 14 hrs of effort. Still, counts of calves (14 for the season) are running
a little higher than normal for this stage of the migration which is consistent with what has been reported from the lagoons and others counting northbound gray whales.
Week 1: The team completed the first week of the annual survey of northbound gray whale cows and calves from the Piedras Blancas Light Station last week, recording 4 calves in the 46 hours of survey effort; about 11 hours of effort was lost to fog and high winds. In addition to gray whales, there were sightings of killer and humpback whales from the watch station.