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

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1960 1997

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Russian sturgeon

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Beluga

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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

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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