Seasonal growth dynamics of two temperate New Zealand finfish, Australasian snapper (Chrysophrys auratus) and yellow-eyed mullet (Aldrichetta forsteri) – two strategies for the common success.

• Main Author: Flikač, Tomislav
• Format: Other/Unknown Material
• Language: English
• Published: University of Canterbury 2018
• Subjects: New Zealand; Pacific; North East Atlantic
• Online Access: http://hdl.handle.net/10092/16110; https://doi.org/10.26021/6452

Proteins sourced from the sea make up a crucial part of global food production and considerably supports sustainability of human demographic growth. However, many fish stocks worldwide are overexploited or depleted and production enhancement is required. Here in New Zealand, certain finfish species are targeted to boost production to address the increase in market demand. One of them is Australasian snapper, Chrysophrys auratus, an iconic New Zealand species with a reputable history of exploitation and research whose growth potential is still not fully understood. When compared with kin species (e.g. Sparus aurata – North-East Atlantic /Mediterranean Sea and Pagrus major from North Pacific) it becomes obvious that a further increase in snapper production and exploitation in New Zealand waters should be possible. The main objective of this thesis was to explore the maximum potential growth capacity and the underlying physiology of snapper, as well as yellow-eyed mullet (YEM), Aldrichetta forsteri, as a comparative model species. The objective was investigated at three levels: First, by measuring growth morphometrics, which includes measuring growth parameters, mass and length, and determining supplementary organosomatic indices from fish kept on an unrestricted diet that enabled maximum growth rates. Second, energy generation, utilisation and partitioning requirements in association with such growth performance could be addressed by investigating metabolic (i.e. resting and maximum metabolic rates and associated aerobic metabolic scope) and digestive (specific dynamic action, SDA – increase in metabolic rates due to feeding) capacities. The third addressed the question – what happens on the biochemical level in organs/tissues actively involved in maximum growth performance? This stage was investigated by determining concentrations of key tissue metabolites and activity of enzymes involved in pathways associated with energy production necessary for growth as well as those related to digestion. Finally, this thesis ...