Dominance behaviour in a non-aggressive flatfish, Senegalese sole (Solea senegalensis) and brain mRNA abundance of selected transcripts

Abstract

Dominance is defined as the preferential access to limited resources. The present study aimed to characterise dominance in a non-aggressive flatfish species, the Senegalese sole (Solea senegalensis) by 1) identifying dominance categories and associated behaviours and 2) linking dominance categories (dominant and subordinate) with the abundance of selected mRNA transcripts in the brain. Early juveniles (n = 74, 37 pairs) were subjected to a dyadic dominance test, related to feeding, and once behavioural phenotypes had been described the abundance of ten selected mRNAs related to dominance and aggressiveness was measured in the brain. Late juveniles were subjected to two dyadic dominance tests (n = 34, 17 pairs), related to feeding and territoriality and one group test (n = 24, 4 groups of 6 fish). Sole feeding first were categorized as dominant and sole feeding second or not feeding as subordinate. Three social behaviours (i. “Resting the head” on another fish, ii. “Approaching” another fish, iii. “Swimming above another” fish) were associated with dominance of feeding. Two other variables (i. Total time occupying the preferred area during the last 2 hours of the 24 h test, ii. Organisms occupying the preferred area when the test ended) were representative of dominance in the place preference test. In all tests, dominant fish compared to subordinate fish displayed a significantly higher number of the behaviours “Rest the head” and “Approaches”. Moreover, dominant sole dominated the sand at the end of the test, and in the group test dominated the area close to the feed delivery point before feed was delivered. The mRNA abundance of the selected mRNAs related to neurogenesis (nrd2) and neuroplasticity (c-fos) in dominant sole compared to subordinate were significantly different. This is the first study to characterise dominance categories with associated behaviours and mRNA abundance in Senegalese sole and provides tools to study dominance related problems in feeding and reproduction in aquaculture.

Diel and seasonal changes in the spatial behaviour of a soft-sediment fish (Solea senegalensis) inside a marine reserve

“…These interpretations are further supported by previous studies on S. senegalensis juveniles and adult specimens kept in captivity, which observed not only higher locomotor activity during nocturnal periods (Bayarri et al 2004), but also higher metabolic rates (Castanheira et al 2011), stronger spawning activity (Oliveira et al 2009) and more frequent feeding after dark (Boluda Navarro et al 2009). Moreover, Fatsini et al (2017) described daytime burying behaviours in dominant soles under experimental conditions. If these results are found to accurately represent S. senegalensis diel patterns in the wild, then they would point towards a high behavioural uniformity within the Soleidae family, as nocturnal activity rhythms have been also described for the closely-related common sole, Solea solea (Sureau & Lagardére 1991), whiskered sole, Monochirus hispidus (Amaral & Cabral 2004) and solenette, Buglossidium luteum (de Groot 1971).…”

Characterization of the different behaviours exhibited by juvenile grey mullet (Mugil cephalus) under rearing conditions

“…food, feeding areas, others). Unlike, in other reared species such as the rainbow trout there is a marked competition for resources, (Øverli et al ., 2004) or the presence of dominance in sole, conferring an advantage of some fish over others access to the food (Fatsini et al ., 2017). Therefore, the absence of hostile behaviours in the grey mullet could be considered as an important factor for the aquaculture of this fish species.…”

Use of an acoustic telemetry array for fine scale fish behaviour assessment of captive Paiche, Arapaima gigas, breeders

“…But if we consider the observed accuracy (<1 m) we still have highly reliable position accuracy as fish average size was 1.67 ± 0.15 m. This accuracy around the meter range is similar to that obtained with Chinook salmon in similar 4,000 m 2 enclosure using a 9‐hydrophone array (Semmens, ) and an 8‐hydrophone array in a 10,000 m 2 natural lake (Baktoft et al., ). Although this technique gives the best accuracy over all other telemetry techniques in turbid environment, the underwater video observation would be of great interest to get complementary and detailed data on fish behaviour as reported for other aquatic animals (Ebner, Clear, Godschalx, & Beitzel, ; Fatsini, Rey, Ibarra‐Zatarain, Mackenzie, & Duncan, ; Mills, Verdouw, & Frusher, ; Struthers, Danylchuk, Wilson, & Cooke, ). Nevertheless in turbid environments the video option is not possible.…”