posted on December 01, 2002 06:17
(updated 19 December 2002)
S.A. Pedersen and L. Storm
Greenland Institute of Natural Resources/Danish Institute for Fisheries Research
Department of Marine Ecology and Aquaculture
Kavalergården 6, DK-2920 Charlottenlund, Denmark
Source - Journal of Northwest Atlantic Fishery Science, Volume 30:47-60
Lipid class and fatty acid compositions were determined in shrimp larvae (Pandalus borealis and P. montagui) collected along transects across banks on the West Greenland shelf in June 1999, May and July 2000. The lipid class contents were investigated as indices of larval shrimp lipid condition and food type. Fatty acid compositions were investigated for lipid biomarkers to establish trophic relationships between larval shrimp and potential prey.
Phospholipids were the dominant lipid class in all six pelagic development stages of larval P. borealis and P. montagui, accounting for 80 to 92% of the total lipid.
In all six stages the contents of free fatty acids were more abundant than triacylglycerol. With increasing larval size from hatching to a carapace length of ~2.3 mm, there was a decreasing trend in the contents of hydrocarbons attributed to reduced amount of phytoplankton in the diet. Triacylglycerol (TG) content to wet weight ratio was investigated as index of nutritional larval condition and survival potential. Proportions of larvae with TG indices >0.2 were relatively high in May 2000 and June 1999, but generally low in July 2000.
The fatty acids 16:0, 16:1n-7, 18:0, 18:1n-9, 18:1n-7, 20:5n-3, and 22:6n-3 were major lipid components of the larvae and their mean proportions varied within relatively small ranges between larval stages. The dominant fatty acids were 16:0, 20:5n-3, and 22:6n-3 with average proportions of about 17%, 20%, and 13%, as percentage of total fatty acids. Biomarkers for algae (16:0, 16:1n- 7, 18:1n-7, 20:5n-3, diatoms: elevated 16:1n-7/16:0 ratios), flagellates (18:0, 18:4n-3, 22:6n-3), and zooplankton (18:1n-9, 20:1n-9, 22:1n-11) indicate that larval P. borealis and P. montagui are omnivorous.
ZI larvae in high concentrations at coastal and fjord stations in May 2000 and most larvae (ZIV–ZVI) from July 2000 were low in lipid. Larvae from June 1999 had relatively high lipid contents probably due to better feeding and growth history. Our results suggest variability in growth and survival expectations of larvae related to variations in larval food availability between years.
Language - English
Publisher - Northwest Atlantic Fisheries Oragnization (NAFO), Dartmouth, N.S., Canada
Publication Date - 2002
Publication Type - Journal Article