Effect of feeding frequency on growth performance, antioxidant status, immune response and resistance to hypoxia stress challenge on juvenile dolly varden char Salvelinus malma

Abstract Although intraspecific interactions likely affect habitat choice and foraging behaviour in animals, our knowledge regarding how these factors interact is frequently limited to either lab or field studies, but not both. We observed pairs of dominant and subordinate drift-foraging Dolly Varden char (Salvelinus malma) in an Alaskan stream, and quantified intraspecific interactions and foraging behaviour. Dominant individuals had higher foraging rates, occupied slower holding velocities and were displaced shorter distances during bouts compared to subordinate individuals. Individuals initiated bouts more frequently from the downstream position, than from lateral or upstream positions. Dominant individuals were more likely to occupy the upstream position after a bout than subordinates, which ensures that dominants have the first opportunity to capture drifting prey.

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Combined phylogenetic analysis of ribosomal ITS1 sequences and new chromosome data supports three subgroups of Dolly Varden char (Salvelinus malma)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f99-103 ◽

1999 ◽

Vol 56 (8) ◽

pp. 1504-1511 ◽

Cited By ~ 22

Author(s):

Ruth B Phillips ◽

Linda I Gudex ◽

Kathleen M Westrich ◽

Alfred DeCicco

Keyword(s):

Phylogenetic Analysis ◽

Dna Sequences ◽

Lake Trout ◽

Salvelinus Alpinus ◽

Dolly Varden ◽

Salvelinus Malma ◽

Dolly Varden Char ◽

The North ◽

Rdna Sequences ◽

Kamchatka River

A phylogenetic analysis of the subspecies of Salvelinus malma (Dolly Varden char) was done using DNA sequences from the first internal transcribed spacer (ITS1) of the ribosomal DNA (rDNA). Sequences were obtained from the northern S. malma malma from the Noatak River, Alaska, and the Kamchatka River, Russia; from the southern North American form S. malma lordi from the Fox River, Kenai peninsula, and Auke Bay near Juneau, Alaska; and from the southern Asian form S. malma krascheninnikovi from Belaya River in Sakhalin Island, Russia. These sequences were combined with others from Salvelinus alpinus (Arctic char) from several locations in the North Pacific and Europe and analyzed using maximum parsimony and neighbor joining algorithms with Salvelinus namaycush (lake trout) as an outgroup. The resulting trees had two well-supported groups: S. m. malma and S. m. krascheninnikovi in one group and S. m. lordi and various populations of S. alpinus in the other. Salvelinus m. malma and S. m. krascheninnikovi were sister taxa, and S. m. lordi was most closely related to S. alpinus from Northwest Territories (S. a. erythrinus). New chromosome data from S. m. malma from northwestern Alaska supported the three named subspecies because S. m. malma from both Alaska and Russia have 2n = 78 compared with 2n = 82 for the two southern forms and the location of the nuclear organizer regions (NORs) was different in each of the three subspecies.

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