TheLojsta Lakes (Swedish:Lojstasjöarna) (sometimes referred to as the Lojsta Lake) (Gutnish:Lojsta träsk) are five lakes inLojsta andStångasockens,[1]Gotland, Sweden. The names of the lakes are (west to east)Bjärsträsk,Fridträsk,Rammträsk,Slottsträsk andBroträsk. Their outflow is in theStorkanalen at Kvarnåkershamn on southweetsern Gotland. Four of the lakes are connected by manmade canals.[2] The Gutnish word for lake isträsk.[3] TheSlottsträsk, the "Castle Lake", (sometimes known asLillträsk) got its name from theLojsta Castle, aMedieval defence-structure, situated by the lake.[4][5]
The lakes form a peculiar landscape, not found anywhere else on the island and reminiscent of therift valleys of central Sweden with steep cliffs and deep lakes.[6] The other lakes on Gotland are very shallow, bowl-shaped depressions in the bedrock, filled with water. For example,Lake Bästeträsk is no more than 5.5 m (18 ft) at its deepest andLake Tingstäde no more than 3 m (9.8 ft). In relation to this the Lojsta Lakes are deep, more than 10 m (33 ft) withRammträsk as the deepest at 15.4 m (51 ft), making it the second deepest lake on Gotland. The deepest lake isSigvalde träsk at 15.8 m (52 ft).[7][8] Lake Sigvalde is situated some kilometers east of the Lojsta Lakes, and is part of the same rift valley as them.[3]
The area around the lakes contains an unusual amount ofreef limestone. This limestone was originally imbedded in sedimentary limestone, but the latter was shaved off during the latestIce age when the inlandice sheet moved, leaving high hills of reef limestone.[9] Along the south side of the lakes is a layer of limestone which exceptionally rich infossils.[10] Most of the cliffs formed from reef limestone have a steep, sometimes vertical, side facing north. In these cliffs (Gutnish:klintar) are small caves, the largest of which can be found atRammträsk andBroträsk.[3]
There are large stands ofwhite waterlilies in the lakes, a plant rarely seen in Gotlandic lakes.[2] Among the fishes that can be found in the lakes areeuropean perch,northern pike,common roach andruffe.[11] It is possible to rent canoes and paddle through the lake system,[4] as well as purchase afishing license forrecreational fishing on the lakes. Fishing competitions are held on the lakes during the winter.[12]
Geographical facts about the five Lojsta Lakes.[7][13]
| Name | Area | Elevation | Average depth | Maximum depth | Volume | Coordinates |
|---|---|---|---|---|---|---|
| Bjärsträsk | 0.008 km2 (0.0031 sq mi) | 45 m (148 ft) | 4.4 m (14 ft) | 11.9 m (39 ft) | 15,000 m3 (530,000 cu ft) | 57°18′43″N18°23′25″E / 57.31194°N 18.39028°E /57.31194; 18.39028 |
| Fridträsk | 0.0883 km2 (0.0341 sq mi) | 45.1 m (148 ft) | 1.9 m (6.2 ft) | 3.3 m (11 ft) | 379,000 m3 (13,400,000 cu ft) | 57°18′57″N18°23′57″E / 57.31583°N 18.39917°E /57.31583; 18.39917 |
| Rammträsk | 0.095 km2 (0.037 sq mi) | 39.5 m (130 ft) | 5.8 m (19 ft) | 15.4 m (51 ft) | 555,000 m3 (19,600,000 cu ft) | 57°19′9″N18°24′23″E / 57.31917°N 18.40639°E /57.31917; 18.40639 |
| Slottsträsk | 0.101 km2 (0.039 sq mi) | 44.6 m (146 ft) | 2.8 m (9.2 ft) | 5.3 m (17 ft) | 44,000 m3 (1,600,000 cu ft) | 57°19′17″N18°25′7″E / 57.32139°N 18.41861°E /57.32139; 18.41861 |
| Broträsk | 0.032 km2 (0.012 sq mi) | 40 m (130 ft) | 4.5 m (15 ft) | 9.5 m (31 ft) | 145,000 m3 (5,100,000 cu ft) | 57°19′7″N18°25′8″E / 57.31861°N 18.41889°E /57.31861; 18.41889 |
