Influence of the marine feeding area on the muscle and egg fatty‐acid composition of Atlantic salmonSalmo salarspawners estimated from the scale stable isotopes

Abstract

Fatty acids in muscle tissue and eggs of female Atlantic salmon Salmo salar spawners were analysed to evaluate the dietary quality of their final feeding areas in the Baltic Sea. The final likely feeding area was identified by comparing stable carbon and nitrogen isotope composition of the outermost growth region (final annulus) of scales of returned S. salar with that of reference S. salar caught from different feeding areas. Some overlap of stable-isotope reference values among the three areas, in addition to prespawning fasting, decreased the ability of muscle tri-acylglycerols to discriminate the final likely feeding area and the area's dietary quality. Among three long-chained polyunsaturated fatty acids, docosahexaenoic acid (DHA; 22:6n-3), eicosapentaenoic acid (EPA; 20:5n-3) and arachidonic acid (ARA; 20:4n-6), the proportions of ARA in total lipids of spawning S. salar muscle and eggs showed a significant negative correlation with increasing probability of S. salar having returned from the Baltic Sea main basin (i.e. the Baltic Sea proper). The results suggest that ARA in muscle and eggs is the best dietary indicator for dietary characteristics of final marine feeding area dietary characteristics among S. salar in the Baltic Sea.

Fatty acid signatures connect thiamine deficiency with the diet of the Atlantic salmon (Salmo salar) feeding in the Baltic Sea

“…In addition to energy reserves used for maintaining the basal metabolism and for swimming, body nutrients are incorporated into developing oocytes. However, particularly concerning HUFAs, the muscle and egg FA composition of spawning female salmon of the River Simojoki were similar (Torniainen et al 2017 ).…”

“…The same conclusion, based on the similarities in the organochlorine profiles between sprat and salmon that ascended the River Simojoki to spawn in comparison to more dissimilar organochlorine profiles between herring and salmon, was earlier reached by Vuorinen et al ( 2002 ). Moreover, results obtained by estimating the feeding area by SIA demonstrated that ARA was present in lower proportions in those salmon that were assigned to the southern parts of the Baltic Sea, although the SIA method could not perfectly segregate the reference salmon of the BS and the BPr (Torniainen et al 2017 ). After having been insignificant for 4 years, M74 returned, apparently as a consequence of an exceptionally strong year class of sprat in 2014 in the Baltic Sea (ICES 2018b ).…”

“…These variations are thought to depend on the feeding area and consequently on feeding to a different extent on sprat and herring. A relationship between FAs and thiamine in the food web is probably the cause of M74, but this needs to be investigated, as stable isotope analysis (SIA) could not provide that information (Torniainen et al 2017 ). Knowledge of the FA composition of salmon caught during their feeding migration that have fed in different areas, and thus on different diets, is needed to resolve the nutritional origin of this reproductive disorder of salmon.…”

Higher Frequency of Fish Intake May Be Associated with a Lower Neutrophil/Lymphocyte Ratio: Anti-Atherosclerotic Effects of Fish Consumption

“…), the portion of fish that was cooked, or how the fish was prepared in this study. Since fish eggs contain high amounts of AA [34], which produces eicosanoid fatty mediators and plays a central role in the activation of neutrophils, especially in the early phase of the inflammatory response [35], it cannot be denied that this study results were affected. In addition, fish are rich in vitamin D, which may have exerted anti-inflammatory effects [36].…”

Population and size‐specific distribution of Atlantic salmon Salmo salar in the Baltic Sea over five decades

“…Despite that, salmon from all 10 populations eventually reach the southern Baltic Sea, population‐specific differences in latitudinal distribution remain also among the largest individuals. Similar to our findings, previous studies on the distribution of salmon at sea originating from Finnish rivers have shown that different salmon populations can feed in different areas of the Baltic Sea (Kallio‐Nyberg et al ., , Kallio‐Nyberg & Ikonen, , Torniainen et al, , ). Our study complements these earlier studies, showing that distribution at sea varies with body size, both within and between populations.…”