Methods for assessing social status in Arctic charr

Abstract

The aggression index is a more reliable method for assessing the social status of Arctic charr Salvelinus alpinus held in small groups, than is food intake or position relative to a defensible food resource. However, care must be taken when assigning rank, as all three of these commonly used methods can result in different social ranks for an individual fish. 2000 The Fisheries Society of the British Isles

The aggressive behavior of Nile tilapia introduced into novel environments with variation in enrichment

“…The initiator of an attack was identified by observing who approached the opponent and directed the attack; the loser was the fish that left the place of attack. From these data, we identified the social status (dominant or subordinate) by calculating the dominance index, which is equal to the number of attacks directed by one fish divided by the total number of interactions in the pair (Bailey et al, 2000). In the control condition, dominant and subordinate fish showed a dominance index of 0.87 ± 0.12 and 0.17 ± 0.18, respectively; in the enriched The data are means (±SD) and were compared by repeated measures one-way ANOVA followed by Scheffé's test (n = 11 pairs for each condition).…”

Is white muscle anaerobic glycolysis capacity indicative of competitive ability in Arctic charr?

“…Several methods exist of measuring the behavioural patterns that discriminate a fish's dominance status (e.g. aggression index, food intake or position relative to a defensible food supply) (Bailey et al, 2000). Two methods were chosen in order to assess muscle metabolism in relation to dominance.…”

The Arctic charr story: development of subarctic freshwater fish farming in Sweden

“…In situations, where dominance hierarchies exist in Arctic charr, we classified individuals as dominant, subdominant and subordinate according to Symons (1970). We developed methods for studying behaviour of fish: first, by assessing social ranks of individual fish in small groups of Arctic charr using aggressive interactions, food intake and position relative to a defendable food source as visible indicators (Bailey et al, 2000). Second, we set up a system where individual fish in small as well as large groups could be automatically monitored using PITtag systems .…”

“…The effect of feeding the fish with defendable or non-defendable food source on the mean growth rate of dominant, subdominant and subordinate fish (lower figure; Brännäs, unpublished results). Each individual was socially screened in smaller groups (five fish) prior to the test according to Bailey et al (2000) and then merged into groups of 20 fish each forming six experimental groups in total, three for each treatment Hydrobiologia (2010) 650:265-274 269 competitive rank (Fig. 4).…”