Source:Auckland Council Research and Evaluation Unit, RIMU
Snapper (Sparidae: Chrysophrys auratus) are one of the most ecologically important species inhabiting Auckland’s waters. However, they are highly valued both commercially and recreationally, and are coming under continuing pressure from intensive fishing efforts. This has led to a significant reduction in stock biomass, declines in genetic diversity amongst populations and changes in the ecosystem structure of reef communities.
Lipids and the associated fatty acid constituents are fundamentally important for growth, as sources of metabolic energy and as endogenous energy reserves for the purpose of reproduction. Within a population, the quantity and composition of an individual’s lipids can vary significantly. This is an important aspect because lipids such as triglycerides and certain fatty acids, play a more integral role than others in developmental processes.
Previous research has suggested that maternal age and size can have profound impacts on embryonic, larval, and juvenile survival, growth rates and functionality, due in part to a greater provisioning of energy rich and biologically important lipids from larger/older females. This was tested, using gas and liquid chromatography, to investigate triglyceride and fatty acid profiles of female snapper across age, size, reproductive stage and condition, throughout its spawning season between November 2015 and February 2016.
Lipid profiling was carried out in both gonadal and liver tissue (the liver is an important storage unit for lipids prior to transfer into the gonads), enabling us to also determine the provisioning strategy used by snapper.
By comparing lipid levels in the liver and gonads prior to and post spawning, we can obtain an indication of where on the capital – income spectrum snapper sit. If they are utilising all their lipids each time they spawn, this would indicate an ‘income’ strategy, whereas drip feeding stored lipids throughout their spawning season indicates a more ‘capital’ approach.
RIMU masters student research summary
MSc thesis, AUT
Lipid quantity, composition and provisioning in the New Zealand snapper/tamure Chrysophrys auratus