Study link between the life history of Atlantic salmon and their behaviour.

Growth patterns might be linked to Atlantic salmon behavioural traits

UNITED KINGDOM
Saturday, March 16, 2019, 00:30 (GMT + 9)

Research in which the University of Stirling participated identified an association between differing growth patterns and body sizes in Atlantic salmon and their behaviour and other developmental characteristics, such as stress responsiveness.

►COPEWELL project aims to demonstrate and quantify the presence and consistency of individual coping styles in farmed fish, establish methods for reliable identification of these, and to provide causal mechanisms for their presence, by addressing the genetic regulation of coping styles at the level of the transcriptome, and by investigating differences in telencephalic structure and function

Dr Sonia Rey Planellas, of the Aquaculture Institute of the University of Stirling, collaborated with colleagues in Norway and the Netherlands on the project.

“One of the main challenges faced by the salmon industry is to understand why individuals within fish populations exhibit significantly different growth patterns and body sizes,” Dr Rey said. “This is important because a significant percentage of the animals do not smoltify – meaning many are lost in production and are potentially living under stressful conditions,” the scientist added.

Dr Rey explains that ideally, the fish would behave in the same way at the same time – but it is not well understood why this does not happen.

This research helps us to understand the different lifecycle strategies and will lead to improvements in the management and welfare of the fish too.

The research, led by Professor Børge Damsgård, of the University Centre in Svalbard, was conducted in Tromsø, where the fish were held and sampled.

Analysis of the data was carried out across a number of partner research institutions and organisations, including the Institute of Aquaculture; the Norwegian University of Life Sciences (Oslo); Radboud University (Nijmegen); Uni Research (Bergen); University of Agder (Kristiansand); Norwegian Institute of Water Research (Oslo); and Nofima (Tromsø).

Left : Development of bimodal growth pattern in Atlantic salmon, Salmo salar (n = 471–478). (a) Mean body mass ± s.e.m. (range 0.12–0.69), in slow-growing lower modal (LM) and fast-growing upper modal (UM) from hatching to endpoint sampling, (b) Weight frequency distribution at endpoint sampling. The dotted line represents the separation between LM (n = 89) and UM (n = 382).

Right: Hypoxia tests with Atlantic salmon, Salmo salar (n = 471). (a) Mean oxygen concentration (mg O2 l−1) in the hypoxia tank in 10 min time units, 80 min before and after the onset of hypoxia (solid line, ±s.e.m.), (b) Mean swimming depth (cm over bottom of the tank, ±s.e.m.) in the same time unit as (a), and (c) Mean swimming depth of the whole fish population (cm over bottom of the tank) as a function of oxygen saturation (% O2).(Click on the image to enlarge it)

The team found that fast-growing Atlantic salmon reach smoltification – where juvenile fish adapt from living in freshwater to seawater – sooner than slow-growing individuals. In addition, the fast-growing fish exhibited proactive, bold characteristics compared to the other group, including active hypoxia avoidance – where the fish attempt to escape low-oxygen conditions – and low stress responsiveness.

The COPEWELL consortium consists of 17 partners from 10 European countries, i.e. Denmark, France, Greece (3), Iceland, Norway (4), Portugal (2), Spain,Sweden,The Netherlands (2) and United Kingdom.(Click on the image to enlarge it)

The study was part of the COPEWELL project, funded by the European Union, which included an Institute of Aquaculture-led sub-project on stress coping styles in salmon, seabass and seabream.

The research, Proactive avoidance behaviour and pace-of-life syndrome in Atlantic salmon, is published in Royal Society Open Science.
 

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