View
1
Download
0
Category
Preview:
Citation preview
CH - 1131 Tolochenaz | Tél: +41 (0)21 802 20 75
Route de Genève | Le Boiron | C.P. 88
www.maisondelariviere.ch
Route de Presinge 150
CH – 1254 Jussy | Tél: +41 (0)22 546 68 87
www.hesge.ch/hepia jean-francois.rubin@hesge.ch
FISHES OF SWITZERLAND,
MANAGEMENT AND ECOLOGY
Survey and investigations in lakes
DR JEAN-FRANÇOIS RUBIN,
Prof HES et Président de la Fondation
Table of contents
Description of the habitat Lake type Formation Spatio-temporal evolution
Origin of the fish
Fishing in lakes
Monitoring Fishing statistics Gill nets Ecosounding Diving
• Skin diving • Submarine
Examples The Arctic charr in Lake Geneva The Whitefish in Lake Joux
Practice Gill net survey Analysis of statistical fishing data
Description of the habitat
Typology
Temporary pond= Water body that sometimes dries up
Pond = Water body without different thermic layers
Lake = water surface div ided into two water bodies with temperatures that vary according to the season
Typology based on fish composition
Typology based on flora composition
Charion Potamion
Lemnion Nymphaeion
Mountain lake
• Diatomae, green algae on the banks
• Some macrophyte
• Char, coregonids , trout
Low altitude lake
• Sometimes eutrophic, bottom with mud
• Phytoplancton frequent, macrophytes on the edges
• Cyprinids , perch, pike
Evolution
Lake Bienne in 4’000 ans
Lake Geneva in 30-50’000 ans
Lake Geneva Origin
Dinosaurs never drank the water of Lake Geneva
15’000 years ago, A geological revolution
Lake and glaciers
Lake habitat
Physicochemical parameters
Water temperature
Air temperature Situation in Switzerland
Années au-dessus de la moyenne 1961-1990 Tendance en Suisse 1864-2011 Tendance dans l’hémisphère nord (terres) 1864-2011
Années au-dessous de la moyenne 1961-1990 Tendance en Suisse 1961-2011
Lake water temperature
Oxygen
Oxygen W
ate
r d
en
sity
Water temperature°C
Late winter
Early winter
Summer
Oxygen
Oxygen concentration at -309 m Limit depth of oxygen 4 mg/l
Phophorus
Eutrophication
Eutrophication
Situation in Switzerland
Evolution in Lake Geneva
Physicochemical monitoring of Lake
Evolution of the lake shores
Veveyse 1886
today
Evolution of the lake shores
Ouchy 1887
Ouchy today
Evolution of the lake shores
Montreux vers 1860
Montreux today
Evolution of the lake shores
Vegetation
Land planning
Origin of the fishes
Origin of the fish species in Lake Geneva
Native fish
Introduced fish
14 species
16 species
30 species
How to research the origin ?
Historical data
Archeological data
Fishing statistics
Scientific s tudies
Example of introduced
species
Carp, Cyprinus carpio
During the Middle Ages, food allowed during fasting were:
• fish
• amphibians
• crayfish and …
• beavers !
The Gold fish
Jeanne Antoinette Poisson, Marquise de Pompadour
Shéhérazade
1730 in France
The Cat fish
From Canada….
To Lake Geneva
The main groups
Salmonids
Cyprinids
The others…
Evolution of the catch
Evolution of the catch
For many years
Fish = Economical ressource
Unclear systematic
Many common names
Management based on economy
Evolution of the catch
In Lake Geneva, 30 species
… only 5 commercially fished
Economical species… managed
Other species… less or not managed
Evolution of the catch
Interest only for fishing
Action on one species
Stocking
Interest for biodivers ity
Action on the habitat
Renaturation
Evolution of the catch
Common biais in the management: Construction of fish ladder
Action after a pollution
Fishing in lakes
Fishing in lakes
Fish monitoring
• Fishing statistics
• Gill nets
• Ecosounding
• Diving
Fishing statistics
Fishing statistics
Fish monitoring
• Fishing statistics
• Gill nets
• Ecosounding
• Diving
Gill nets
Gill nets are selective depending on the mesh used
Gill nets
Gill nets
Gill nets
Gill nets
Gill nets
Gill nets
Gill nets
Gill nets
Fish monitoring
• Fishing statistics
• Gill nets
• Ecosounding
• Diving
Ecosounding
Ecosounding
Ecosounding
Fish monitoring
• Fishing statistics
• Gill nets
• Ecosounding
• Diving
Diving
Recommended