Upload
others
View
5
Download
0
Embed Size (px)
Citation preview
Status of long distance migratory fish species (sturgeons, shads) in
Lower Danube Region
Lenhardt Mirjana
Institute for Biological Research and Institute for Multidisciplinary Research University of Belgrade, Serbia
Migratory fish species
• There are approximately 30,000 fish species worldwide of which only 165 species are migratory
• They can move alone or in schools
• the key role in their return to natal place has use of magnetic fields, environmental cues, and olfactory memory
• Migratory fish species are important as fishery resource and they have economic, cultural and natural values
Anthropogenic pressure
• over-exploitation, illegal fishery
• river modifications due to navigation
• dam building, hydropower plant
How to achieve effective protection of migratory fish species?
To improve:
• knowledge about rivers and environments
• fish physiology
To establish:
• collaboration among many stakeholders: local, state and regional agencies, conservation organizations, research institutions, the navigation company, and the hydroelectric company where new technologies can help to restore rivers
The Danube still has 863 km of free running river with the first barrier represented by the
Iron Gate II dam
Danube – long migratory fish species
In this part of the Danube River from the Black Sea still migrate three anadromous sturgeon species
• beluga sturgeon, Huso huso
• Russian sturgeon, Acipenser gueldenstaedtii
• stellate sturgeon, Acipenser stellatus
and two shads
• Pontic shad, Alosa pontica
• Black Sea shad, Alosa tanaica
Status in accordance with IUCN Red List
Three sturgeon species are Critically endangered
Pontic shad is Vulnerable
Black sea shad is Least concern
The Danube Gorges - Mesolithic and Early Neolithic Animals that were ‘coming back’,
repeating their journey year after year
The majority of whirpool fishing spots mentioned by Mihailo Petrović overlap with the locations of
Mesolithic- Neolithic sites in the Gorges
Sturgeon catch by unbaited hook lines
Iron Gate I dam was designed in part to improve navigation (strong current, rapids and exposed rocks were hazardous to shipping)
Picture by Dr J. Jeffery Isely, South Carolina Cooperative Fish and Wildlife Research Unit, Clemson University
Female beluga, caught in 2001 downstream Djerdap II47 years old
Male beluga caught in 2001 downstream Djerdap II, 35 years old, 110 kg
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
22000
CA
TC
H (
kg
)
Stellate sturgeon
1970
Djerdap I Dam
1984
Djerdap II Dam
1960 1997
*
*
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
22000
CA
TC
H (
kg
)
Russian sturgeon
1970
Djerdap I Dam
1984
Djerdap II Dam
*
*
1960 1997
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
22000
CA
TC
H (
kg
)
1970
Djerdap I Dam
*
*
1984
Djerdap II Dam
Beluga
1960 1997
Sturgeon catch
in Serbia
Sinusoidal oscillation model for beluga sturgeon and estimation the danger of extinction
Estimated extinction time for beluga
Sinusoidal oscillation model for Russian sturgeon and estimation the danger of extinction
Estimated extinction time for Russian sturgeon
Anthropogenic pressure in the Black Sea
Christian custom of local people
to eat Pontic shad during Lent
Shads migration in Lower Danube Region
Danube Delta, total length 25.4 cm, weight 137.6 g, condition factor 0.84
862 kilometer of the Danube, total length 25.6 cm, weight 85.7 g, condition factor 0.51
Investigation of Pontic shad in Romania
Catch statistics of Pontic shad from the Romanian portion of the Danube River
y = 1E-10x6 - 7E-10x5 - 3E-06x4 + 0.0003x3 - 0.0114x2 + 0.1484x - 0.2059R² = 0.4772
0
1
2
31920
1923
1926
1929
1932
1935
1938
1941
1944
1947
1950
1953
1956
1959
1962
1965
1968
1971
1974
1977
1980
1983
1986
1989
1992
1995
1998
2001
2004
2007
Catc
h (
t x 1
000)
Catch evolution of Pontic shad (Alosa imaculata)from Danube delta, Romania
Reconstruction (1920-2013) and forecast (2014-2033) of the mean annual catch of Alosa immaculata from
the Danube River in Romania
Pontic shad in Lower Danube Region
• Pontic shad is protected in Serbia from 1993 by Decree of Natural Rarities Protection.
• It is included in Red Book of Bulgaria as vulnerable The prohibited period for catch -15 April to 15 May
• In the Danube Delta Red Book in Romania Pontic shad is stated as not threaten. The prohibited period:
• Black Sea – rkm 43 20-24 April
• Rkm 43 – rkm 238 24 April – 13 May
• Rkm 238 – rkm 845.6 28 April – 27 May
• Pontic shad has status data deficient in Ukraine
Satellite and Airborne Remote Sensing Applications for Freshwater Fisheries
• New sensor platforms and technology now yield imagery with higher spatial, temporal, and spectral resolutions, which has accelerated development of remote sensing products that more accurately characterize aquatic environments
• Deriving river bathymetry using space borne remote sensing techniques
Using high resolution monitoring of water level (red line) and temperature (black line) to predict
movements of migratory sea trout (gray bars)
Ion Gate II dam
Specific Objectives of MEASURES• (1) Identification & mapping of migratory fish habitats.
• (2) Development of a harmonized & improved strategy (including prioritization) for the re-connection of migratory fish habitats to secure and re-establish vital ecological corridors in the DRB to be implemented into policy and management plans.
• (3) Provision of a strategy to conserve Danube sturgeon species, including an appropriate design of broodstockfacilities.
Workpackages in the MEASURES project
WP M
Project
Management
BOKU
Communi-
cation
WWF - RO
WP C WP T1
Infosystem Eco-Corridors
IBRA
WP T2
Mapping the Corridor
DDNI
WP T3
Strengthen Migratory Fish
NAIK-HAKI
WP T4
Securing the Eco-Corridor
BOKU