Onset of Dormancy in the Copepod Calanus pacificus californicus Off Southern California
Abstract
This grant supported the Ph.D. dissertation research of Catherine L. Johnson. Dr. Johnson was awarded her Ph.D. in May 2003. The research conducted under this grant examined the onset of and emergence from dormancy of C. pacificus californicus and its distribution at depth during dormancy in the region off Southern California. A novel method using hormonal differences between dormant and active individuals was developed to examine preparation for dormancy. The vertical distribution and abundance of dormant C. pacificus were described over eleven months at San Diego Trough (SDT) and at basin and open-water stations during three months. Variation in molting hormones was characterized through the CV molt cycle, and both molting-hormone level and jaw phase morphology were used to examine changes in molt phase indicating onset of dormancy in surface CVs. The observed dormancy response did not support hypotheses that either photoperiod or food limitation alone induces dormancy. Dormant copepods were present at all stations examined between June and January. At SDT, they occupied the California Undercurrent at the beginning and end of the dormant period, indicating a poleward transport for part of the year. The abundance of dormant CVs was not different in basin and open-water stations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 10, 2003
- Accession Number
- ADA414753
Entities
People
- David M. Checkley