RNA content of the Antarctic krill (Euphausia superba DANA), an estimator of natural growth rate

• Main Author: Tsutomu Ikeda
• Format: Report
• Language: English
• Published: Japan Sea Regional Fisheries Research Laboratory 1989
• Subjects: Antarctic; The Antarctic; Wilkes Land; Antarc*; Antarctic Krill; Euphausia superba; Polar Biology; Proceedings of the NIPR Symposium on Polar Biology
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=5046; http://id.nii.ac.jp/1291/00005046/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=5046&item_no=1&attribute_id=18&file_no=1

The ribonucleic acid (RNA) content of the krill was measured on specimens collected during the KAIYO-MARU cruise to the Wilkes Land, Antactica, January 1980. Of 41 specimens analysed, the RNA content varied from 2.5 to 8.2% of body protein (mean: 5.1%). A higher RNA content was seen in smaller specimens, and the relationship was log Y=-0.34logX+1.27, where Yis the RNA content as percent of protein, and X is the body size as mg protein. Combining this equation with the RNA-growth rate equation of BÅMSTEDT and SKJOLDAL (Limnol. Oceanogr., 25, 304,1980), the growth rate of the krill was estimated to be 0.17-0.19 mm day^<-1> for specimens greater than 30 mm body length. Assuming a favorable feeding period of 6 months in a year for this animal, post-larvae could grow to the final size adults in 201 days. Validity of these results depends on the RNA-growth rate equation. In the light of possible species-specific variation in the RNA-growth rate relationship, this relationship needs to be established for the Antarctic krill in future laboratory experiments.