Life-history traits of chaw, Salvelinus alpinus, from a High Arctic watercourse on Svalbard

Three arctic charr (Salvelinus alpinus) morphs coexist within the Dieset wa tercourse (79 degrees 10 'N, 11 degrees 20 'E) on Spitsbergen, Svalbard. Sm all freshwater resident charr exhibited a very slow growth rate, while larg e freshwater resident charr grew at a rate comparable to that reported for cannibalistic charr elsewhere. First-time sea migrants of the anadromous ch arr were similar in size to their more southern-living Norwegian conspecifi cs, but on average two years older. The average number of sea runs before f irst-time spawning was 3.6 for males and 4.4 for females. Veteran migrants displayed growth comparable to that of anadromous charr from more southern populations. In all three morphs, sex ratio did not differ from unity. The short-lived small residents matured from an age of 4 years, 3 to 4 years ea rlier than did large residents and anadromous charr. The majority of small resident and anadromous charr spawn a maximum of three times, while large r esident charr may spawn up to seven times. Although 69% of large resident c harr were older than 15 years, only 5.7% of reproductive anadromous charr e xceeded this age. This divergence may indicate different reproductive strat egies between the two morphs. There was no evidence of reproductive isolati on between these High Arctic charr morphs.