Bishop, 1971


Bishop, F.G. (1971) Observations on spawning habits and fecundity of the Arctic grayling. The progressive Fish-culturist, pp. 12-19

Associated characteristics

Species Development state Trait Primary Data Secondary Data
Thymallus arcticus Spawning conditions Mating system The male and female were near the bottom. They were side by side, touching each other. The male had his fin erect and partly laid over the female, in much the same way it was laid on the boot or rock during the vibration. The female gaped widely, but the male did not gape until just before the act was over. The whole act took perhaps 7 seconds No category
Thymallus arcticus Spawning conditions Nycthemeral period of oviposition Montana grayling slackened its spawning activities after 11 p.m. [Also noted that in the afternoon the intensity of the spawning rose, reached a maximum when the water was warmest, and then gradually decreased in the evening] Day
Thymallus arcticus Spawning conditions Parental care The male swam off as soon as the act was over, the female stayed around for a few seconds and then also sawm off. Male parental care
Thymallus arcticus Spawning conditions Spawning substrate Studies showed that pure mud, sand, and clay were not chosen at all, only gravelled areas were used. Ambiguous
Thymallus arcticus Spawning conditions Spawning site preparation No redd was formed, but the eggs were covered by the loosened bottom material Susbtrate chooser
Thymallus arcticus Spawning conditions Spawning temperature Most of the spawning took place in a water at a temperature of about 10°C 10.0 °C
Thymallus arcticus Spawning conditions Spawning water type The spawning area of Providence Creek was a depper part of the stream just below a riffle used as a feeding area, the current about 25 feet per second Flowing or turbulent water
Thymallus arcticus Spawning conditions Spawning depth The depth was about 3 feet 3.0 m
Thymallus arcticus Male Male sexual dimorphism Territory-holding dish in their study had a different color, the flanks and back becoming a brownish or dark grey, while the tip of the nose in many specimens became white Absent
Thymallus arcticus Egg Egg adhesiveness The eggs were very adhesive when first stripped, but this stickinessgradually disappeared as the eggs became water-harened Adhesive
Thymallus arcticus Egg Incubation time 13.7 at 8.8°C 13.7 days
Thymallus arcticus Female Relative fecundity 310.9 eggs per ounce of fish [Also desribed as 376 eggs per ounce] 310.9 thousand eggs/kg
Thymallus arcticus Female Age at sexual maturity Fish in the 6- to 9- year group made up 93.5 percent of the run 6.0 years
Thymallus arcticus Egg Degree-days for incubation 216.5 [At 8.8°C], also described at 250 216.5 °C * day
Thymallus arcticus Egg Temperature for incubation 8.8°C 8.8 °C
Thymallus arcticus Spawning conditions Spawning migration distance Apparently grayling migrate from the lakes and larger streams to the smaller tributaries, which are the first to become free of ice No data
Thymallus arcticus Egg Egg size after water-hardening The average diameter of 100 measurements of water hardened eggs was 2.7 mm 2.7 mm
Thymallus arcticus Egg Oocyte diameter The diameter of fresh eggs measured 2.6 mm [Also found 2.5 mm before the eggs were water-hardened] 2.6 mm
Thymallus arcticus Female Absolute fecundity The 15 fish had an average of 9670 eggs [described in other studies as 4000 to 7000, but a few of the largest females yielded more than 10000 eggs each] 15.0 thousand eggs
Thymallus arcticus Spawning conditions Spawning season The spawning of the grayling in Gret Slave Lake and surrounding areas takes place during spring - from April to May. This spawning period corresponds to the breakup of the ice on the rivers ['April', 'May', 'June']
Thymallus arcticus Larvae Sibling intracohort cannibalism Most of the grayling were eating fish eggs, but it was impossible to tell whether they were grayling of pike eggs Absent
Thymallus arcticus Larvae Onset of exogeneous feeding Young grayling begin taking food as late as 9 days after hatching 9.0 °C * day
Thymallus arcticus Female Age at sexual maturity Fish in the 6- to 9- year group made up 93.5 percent of the run 6.0 year
Thymallus arcticus Spawning conditions Spawning release Grayling females in Providence Creek release most, or all, of their eggs in one act, because, as nearly as could be ascertained, no female was caught with only part of her ripe eggs remaining in the ovary No category