Proximate composition, energy content, and fatty acid composition of marine species from Campbell Plateau, New Zealand

Abstract

Campbell Plateau is an important fishing ground for the main commercial New Zealand species. Yet, studies on trophic interactions between species and their nutritional values are limited. The objectives of this study were to determine the proximate composition and energy contents of selected commercial and non-commercial marine species from Campbell Plateau and their fatty acid (FA) composition, and to evaluate the degree to which species can be differentiated by their FA compositions. We analysed 43 fish specimens from 5 different species (Macruronus novaezelandiae, Lepidorhynchus denticulatus, Pseudophycis backus, Hemerocoetes spp. and Squalus acanthias), 17 cephalopod specimens from 2 species (Nototodarus sloani and Enteroctopus zealandicus), and 6 Metanephrops challengeri (crustacean). The variation of energy contents between fish species was not significant, but their lipid and protein contents varied significantly. FA signatures distinguished the species analysed and, at a broader scale, the type of habitat. Within-specie s variability was important for benthic species. In general, the diet inference from FA trophic markers was consistent with reported diets from stomach contents.

Foraging diversity in lactating New Zealand sea lions: insights from qualitative and quantitative fatty acid analysis

“…The most important differences were 20:5n-3, 16:3n-4 (more concentrated in benthic individuals), and 18:1n-9 (more concentrated in mesopelagic females). The FA 20:5n-3 is found in higher concentrations in scampi and arrow squid than in fish, while 18:1n-9 is in high levels in hoki and rattails (Meynier et al 2008). Consistently, QFASA predicted more scampi and squid in the diet of benthic divers and more hoki and rattails in the diet of mesopelagic divers, although there was an overlap in the diet estimations of some individuals with different strategies (Fig.…”

“…The energy content and FA profiles of the common marine species found in the Auckland Islands region have been determined in a previous study in an attempt to build a reference prey library for QFASA estimations (Meynier et al 2008). Fresh specimens of hoki (Macruronus novaezelandiae), rattails (Macrouridae), southern arrow squid (Nototodarus sloanii), scampi (Metanephrops challengeri), opalfish (Hemerocoetes spp.…”

“…The diets of individual sea lions were estimated using QFASA described by Iverson et al (2004) and a prey FA library from the Auckland Islands region (Meynier et al 2008). The model takes the mean FA profiles of each prey species in the prey library and estimates the mixture of prey FA profiles that comes the closest to match the FA profile of the predator's adipose tissue.…”

Higher trophic level prey does not represent a higher quality diet in a threatened seabird: implications for relating population dynamics to diet shifts inferred from stable isotopes

“…Furthermore, the smaller body size of ERP relative to Magellanic penguins (bill length 21 % shorter, Marchant and Higgins 1990;Yorio et al 2001) may limit the ability of ERP to capture larger, reproductively mature fish which are typically of higher energy density (Anthony et al 2000). Additionally, the higher chick δ 15 N values in 2012 relative to 2011 likely also reflect a higher proportion of low-lipid cephalopod prey fed to chicks in 2012 (Cherel and Ridoux 1992;Meynier et al 2008). Small cephalopod beaks (n = 2 to >50) were found in the stomach contents of five chicks killed by Brown Skuas Catharacta antarctica lonnbergi in 2012, but no beaks were present in five skua-killed chicks in 2011 (K.W.M.…”

“…Fish generally have a higher lipid and energy density than zooplankton or cephalopods (Clarke and Prince 1980;Cherel and Ridoux 1992;Meynier et al 2008). Additionally, fish are more rapidly digested by seabirds, including SRP (Jackson 1992), than are crustaceans or cephalopods (Wilson et al 1985;Jackson et al 1987).…”