Wax esters versus triacylglycerols in myctophid fishes from the Southern Ocean

• Published in: Antarctic Science
• Main Authors: Phleger, Charles F., Nelson, Matthew M., Mooney, Ben D., Nichols, Peter D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1999
• Subjects: Geology; Ecology, Evolution, Behavior and Systematics; Oceanography; Antarctic; Southern Ocean; The Antarctic; Antarctic Peninsula; Elephant Island; Antarc*; Antarctic Science; Euphausia superba; Copepods
• Online Access: http://dx.doi.org/10.1017/s0954102099000565; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102099000565

Five species of myctophid fishes were collected by trawl from the Elephant Island region of the Antarctic Peninsula between 60°30′–62°S and 55°–61°30′W. Two species, Gymnoscopelus braueri and Krefftichthyes anderssoni were lipid-rich (406–456 mg g −1 dry weight whole fish) with wax esters (WE) the major lipid class. In three species, G. opisthopterus, G. nicholsi , and Electrona carlsbergii , triacylglycerols (TAG) were the major lipid. All fish had oily bones, with values up to 471 mg g −1 dry weight in the vertebral centra of K. anderssoni. The principal fatty acids of the TAG-rich myctophids included the monoenes 18:1(n-9) and 20:1. There were lower levels of 16:0 and 18:0 saturated fatty acids. Polyunsaturated fatty acids (PUFA) were present at higher abundance in the TAG-rich E. carlsbergii and G. opisthopterus , with lower levels in G. nicholsi. In comparison, the WE-dominated species contained lower levels of PUFA than in the TAG-rich species. The principal fatty acids of the WE-rich myctophids included the monoenes 18:1(n-9), 16:1(n-7), and 18:1(n-7), with lower levels of the saturated acids 16:0 and 18:0. Fatty alcohols were dominated by 16:0 and 14:0 and the monounsaturated 18:1(n-9) with 16:1(n-7), 18:1(n-7), and 20:1(n-9). Based on the fatty acid profiles, the diet of G. opishtopterus and G. nicholsi , previously thought to be mainly Euphausia superba , is suggested to include copepods and other zooplankton with only a minor krill component, possibly consisting of other species than E. superba.