┴ al■jˇlegri rßstefnu um bleikjurannsˇknir sem haldin var Ý ReykjavÝk 2. til 5. ßg˙st 2006 sřndi J. Brian Dempson frß Kanada tv÷ kvikmyndaskei af bleikju. Myndirnar eru teknar ß um 50m dřpi Ý Gander vatni sem er ß Nřfundnalandi og sřna bleikju vi fŠuleit ß dj˙pbotni vatnsins. Myndkeiin eru ßhugaver ■vÝ ekki eru til m÷rg slÝk skei sem sřna atferli bleikju Ý nßtt˙rulegu umhverfi. Sjß mß fiskinn sem er 15 - 18 cm langur, synda um og rˇta Ý botninum eftir ßnam÷kum og lirfum rykmřs.
Gandervatn er (48░55 N, 54░35┤ W) stˇrt, 113 ferkÝlˇmetrar og 288 metra dj˙pt, nŠr 270 m undir sjßvarbor. Hefur bleikja veist Ý net Ý vatninu niur ß 280 metra dřpi sem er meal dřpstu staa sem bleikja hefur veist ß. Myndirnar eru teknar me kafbßti.
Remarkable videoclip of Arctic charr in deep waters!
At the5th International Arctic charr Symposium (August 2th-5th 2006, ReykjavÝk, Iceland), J. Brian Dempson at Fisheries and Ocean Canada, showed two videoclips of Arctic charr (Salvelinus alpinus) acting in the profundal habitats at great depths in Gander Lake, Newfoundland. We found the videoclips very interesting because video-recordings of Arctic charr behaviour in nature are rare, not to mention if the behaviour does not appear to have been observed before, as seems to be the case here.
The video presented here displays Arctic charr, 15-18 cm in total length, on the bottom of Gander Lake at 53 m depth (173 feet) on September 8th, 2005. On this video, tracks the charr makes in the substrate can clearly be seen as it swims along the bottom, appearing to burrow, somewhat, in the sandy-silt bottom. äPuffingô by the charr can also be seen at times, i.e. on several occasions the charr seems to suck in water and/or debris and spit it out again, indicating that it might be filtering material, even that it is feeding, perhaps on some sediment organisms, e.g. oligochaetes, chironomids, or freshwater sphaeriid clams. The tracks made by the charr resemble very much tracks on soft mud bottom made by diving ducks when feeding on chironmidae larvae, e.g. as is well known from Lake Myvatn, Iceland.
On the bottom left part of the videoscreen D is the depth in meters and H is directional heading value (somewhat meaningless here). Information on the videocamera can be found at the follwing link.
Gander Lake (48░55 N, 54░35┤ W, Newfoundland), is a large lake, 113.2 km2 in surface area, and deep (288 m) whose maximum depth is about 270 m below sea level. Arctic charr in Gander Lake has been caught with gillnets down to a depth of 280 m depth, which is among the deepest recorded Arctic charr to date.
To watch the video simply click on the icon below.