PRESENT AND PERSPECTIVES OF STURGEON CONSERVATION
IN THE LOWER DANUBE RIVER, ROMANIA
Suciu R. *, Knight C.M.**, Onara D.F*., Paraschiv M.*, Taflan E.*, Iani M.*, Holostenco D.*
* Sturgeon Research Group /Danube Delta National Institute (DDNI), Tulcea, Romania
**Norwegian Institute of Water Research (NIVA), Oslo, Norway
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Outline:Why conservation measures?
Goals of conservation and recovery program
Conservation regulation of May 2006
Preserving genetic diversity
First recaptures and post stocking evaluation
Perspectives
Discussions
News on ongoing projects
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Why conservation measures ?
- Option to recover: “build up of stocks by hatchery production and return brood stock to home system”
(Cowx 1999)
1990-1999 :10 years of intensive and uncontrolled fishing(Navodaru et. al. 1999)
Arguments: - decline of catches - disrupted age class structure- poor / lacking natural recruitment
•stellate sturgeon severely suppressed•Russian and beluga sturgeon - relict status facing extinction by Alee effect (Alee 1931)
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Example of Alee effect: Recession and extinction of European sturgeon (Acipenser sturio) from rivers of Western Europe
■ Catches of European sturgeon in the Lower Elbe River during 1890 – 1918 (Kinzelbach, 1997). Note that extinction occurred during only 10 years (1909 - 1918)
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Decreasing of catches:A. güldenstädti (1920 - 2005)
Catches of Danube sturgeon recorded in Romania during 1920 - 2005
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250
1920
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Year
[tons
]
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Decreasing of catches:H. huso (1920 - 2005)
Catches of beluga sturgeon recorded in Romania during 1920 - 2005
0
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1920
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Anul
[ton
e]
Iron Gates I
No data
Iron Gates II
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Decreasing of catches:A. stellatus (1920 - 2005)
Catches of stellate sturgeon recorded in Romania during 1920 - 2005
0
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1920
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Year
[tons
]
Under-reporting of catches
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
0
500010000
15000
2000025000
3000035000
40000 [Kg]
2002 2003 2004 2005Year
Sturgeon landings - Romania - 2002- 2005
Beluga sturgeonDanube SturgeonStellate sturgeonTotal [Kg]
37 tons
29 tons
17 tons 11 tons
Sturgeon catches in Romania (2002 - 2005)
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Methods: (1) Age determination Pectoral bony fin rays collected by professional fishermen
cross-sections
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
• stellate sturgeon (A) cohort consists mainly of first time spawners (6 – 8 years old) • Russian sturgeon (B) and beluga sturgeon (C&D) clearly lack first time spawners
Age class structure (2003 - 2004):
0
5
10
15
20
25
14 15 16 17 18 19 20 21 22 23 24
Age [years]
frequ
. %
(N landed = 97; N sampled = 25)C
(N captured = 344; N sampled = 137)
05
10152025
3035
5 6 7 8 9 10 11 12 14 18
Age [years]
freq
u. [%
A
0
5
10
15
20
25
30
35
15 16 17 18 19 23 27Age [years]
Freq
. [%
]
( N landed = 29; N sampled = 12 )B
( N landed = 62; N sample = 22)
0
5
10
15
20
25
30
35
40
16 17 19 20 21 23 24
Freq. [%]
Age [years]
D
Stellate sturgeon males (2003)Russian sturgeons / mixed sexes (2003)
beluga sturgeons / mixed sexes (2003) beluga sturgeons females (2004)
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
(2)Catching larvae in the RiverFishing with drift nets set at 12 – 15 m depth in the Danube River, downstream of potential spawning sites, in years 1999, 2004, 2007 and 2008, we collected six Acipenser (?) / Huso (?) larvae (Paraschiv et al. 2007).
April 28, 2007 Danube River Km 310
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
bp
1500
850
400
200
50
Identification of larvae captured in the Lower Danube River (1999 - 2008)
(Onara 2008) using cytochrome b region of mt DNA cut with MseI)
A d u l t s L a r v a e
R e f e r e n c e s a m p l e s
May 29, 1999
May 2, 2008
May 20-21, 2004
Apr. 28, 2007
husoruthenusstellatus güldenstädti
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Methods:(3) Bottom drifting trammel net to capture YOY
(90 x 1.8) m , 20 mm mesh size
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Beluga sturgeon- Huso huso
0123456789
101112
2000 2001 2002 2003 2004 2005 2006 2007Year
CPUE
Russian sturgeon - Acipenser gueldenstaedti
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
2000 2001 2002 2003 2004 2005 2006 2007Year
CPUE
Stellate sturgeon - Acipenser stellatus
00.2
0.40.6
0.81
1.21.4
1.6
2000 2001 2002 2003 2004 2005 2006 2007
Year
CPUE
Sterlet - Acipenser ruthenus
02468
10121416
2000 2001 2002 2003 2004 2005 2006 2007Year
CPUE
Natural recruitment in the Lower Danube River (2000 – 2007)Juvenile index (Paraschiv et al. 2007)
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Conservation regulation of May 2006
• Migratory Fish Monitoring Station (Isaccea, Danube River km 100)
•joint Ministerial Order (May 4, 2006):- conservation of wild sturgeon populations / stocks - development of sturgeon aquaculture in Romania
•allows only the capture of brood fish from the wild (special authorization) for artificial propagation:
- supportive stocking of the Danube River -development of sturgeon aquaculture
•use non-destructive artificial propagation procedures
•release PIT tagged wild brood fish back in the Danube River
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Goals of the conservation and sustainable use program (Suciu et al. 2007)
•Prevent population extinction
•Preserve genetic diversity of populations / stocks
•Rebuild natural age class structure by implementing of Supportive Stocking Program (SSP)
•Restore natural recruitment
•Develop sturgeon aquaculture to lower market pressure on wild populations / stocks
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Structure of Supportive Stocking Program:•catch and PIT tag of wild brood stock in limited number of sites (2) and time ( 15.02 – 15.04)•use minimum effective annual number of brood fish•apply non-destructive artificial propagation procedure
•apply fertilization scheme to maximize genetic variability
•release all spent brood fish back in the Danube River
•grow offspring separately in families to a TL ≥ 15 cm•tag all young sturgeons individually using CWT•stock young sturgeons close to catch sites of brood fish•monitor survival in the DR and the Black Sea costal waters
•conduct post stocking evaluation
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Capturing of wild adult sturgeons(Suciu et al. 2007)
Fishing of live wild adult sturgeons permitted only in two locations:
* Km 120 - 130 (downstream of Grindu)* Km 40 – 48 (on the Borcea branch)
Fishing sites - surveyed day and night by the FisheryInspection to: prevent illegal catch
PIT tag the fish
Give a chance to all other sturgeons to spawn naturally in the river.
Bulgaria
Romania
Serbia
Ukraine
BlackSea
Iron Gates I (1974)
Iron Gates II (1984)
Danube River
Tulcea
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Catching and tagging wild adult sturgeons• All brood-fish captured live and immediately PIT tagged,
transported to hatcheries - kept in covered concrete tanks. • All PIT serial numbers – recorded - data base at
NAFA Romania.• Clip fins were sampled for later DNA analysis in DDNI lab.
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Preserving genetic diversity: (i) minimal effective number of brood fish + multiple male fertilizing
Sperm was extracted with a silicon tube attached to syringes -kept on ice for “multiple male” fertilization
Ovulation - induced using Nerestin - synthetic product with soft action - avoids over – maturation of brood fish.
Eggs - obtained by stripping after a minor internal incisionin the ovarian duct
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
YOY grown in families and tagged individually - CWT(Paraschiv et al. 2008)
Tags injected alternatively in right /left pectoral fin (2005 / 2006)
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Stocking the Danube River
• data base with CWT serial numbers of young sturgeonsstocked from each family was established at DDNI andNAFA Romania.
• artificially produced young sturgeons - stocked closeto locations where their parents were captured
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Preserving genetic diversity:(ii) Releasing of wild brood fish after artificial propagation
•172 wild sturgeons - captured in year 2007 for SSP:16 – beluga sturgeons; 5 - Danube sturgeons88 – stellate sturgeons; 60 - sterlets
•After artificial propagation 169 – released back in the Danube River
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Preserving genetic diversity:(iii) cryopreservation of sperm (Suciu et al. 2008)
- to enable multiple male fertilisation in species lacking brood fish (A. güldenstädti) – cryopreservation of sperm was applied for the first time in May 2007 at Isaccea hatchery
-Sturgeon sperm bank - 24 ml of high quality sperm from: 2 stellate sturgeons1 sterlet 2 Russian sturgeons
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Preserving genetic diversity:(iv) preserve rare genotypes
(Onara et al. 2007)
RFLP of mtDNAregions ND 5/6 and Cyt b
A. stellatus brood fish having rare ND 5/6 (II - VI) and Cyt b (II - III)haplotypes migrate in the Danube in early spring
Their spawning grounds are more distant from the seaand therefore were historically more vulnerable to the fishery
To preserve the genetic diversity of A. stellatus rare mtDNA genotypes should be used in SSP separately
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Duration of SSP:Until full restoration of natural recruitment and rebuilding of natural age class structure butNOT longer than 10 years
YOY stocked into the Danube River (2005 - 2008)Year Huso huso A. gueldenstaedti A. stellatus
[No. of specimens] Mean [No. of specimens] Mean [No. of specimens] Mean TW [g] TW [g] TW [g]
2005 2 500 235 7 800 33 2006 12 500 123 Ø 53 000 282007 15 000 345 96 500 96 2008 20 000 142 40 000 213 25 000 35 Total 47 500 139 000 85 800
Cost of SSP: ≈ 1 million € / year
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Survival of tagged juveniles• During experimental fishing to monitor natural recruitment, in June –
Sept 2007 seven CWT tagged stellate sturgeons were captured at Danube R. Km 119 and 100.
• Each fish had CWT tags in their left pectoral fin, showing that they were tagged and released in December 2006 on the Borcea branch (Km 39).
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
First post stocking evaluation (June - Sept 2007)
Average TL of stellate sturgeon recaptured after: 6 month 37.75cm8 month 43.18 cm
i.e. growth rates of 3.27 - 3.45 - cm / month
Average TL of stellate sturgeon at release (Dec. 2006): 17 cm
Average annual growth rate recoded in white sturgeonsstocked in the Kootenai River was 6.4 cm / year (Ireland 2002)
June 5, Danube Km 119
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Discussion:
Difficulties:
• in some years insufficient number of brood fish of Russian sturgeon • deficient enforcement of regulations (3 governments in just 3years)• illegal fishing / poaching of sturgeons still present •Monitoring Center Isaccea of DDBRA still not operational
Weaknesses of SSP:
• in some years stocking delayed due to difficult public acquisition process of young sturgeons (improved in 2009)
• lack of involvement of local fishermen communities• survival evaluation survey still missing• fall migrants still not propagated separately
Satellite telemetryMay 2009 – for the first time on the Danube River and in Europe
Ongoing projects: Best Combat (RO & NO)
Satellite telemetryArgos satellite - first locations of tagged beluga in the Black Sea
10.08.2009 / 75d
St. George
Chilia delta
30.07.2009 / 65d
DIDSON camera
First Dual Frequency Identification Sonar (DIDSON - € 75,000) in Romania & lower Danube River
Dan Ericson / USA Kate Hawley / NIVA- No
Marian Iani / DDNI - Ro
DIDSON
viewing large fish in deep & turbid water/ Danube River
Acoustic telemetry(Oct. – Nov. 2009)
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Perspectives:
JOP Black Sea (2010 - 2012): All Black Sea survey (CWT) of survival and distribution of young sturgeons stocked in the Danube River (2005 -2009) (TR, BG, RO, UA & GE)
BestCombat project (2009 - 2011): (i) present and ancient genetic diversity in beluga sturgeon - microsatellite and mtDNA genes; (ii) location of essential spawning and wintering habitats in the river using up to date acoustic telemetry and DIDSON camera; (iii) finalizing survey of movements and distribution in the sea using satellite transmitters.
Improving SSP (2010 - 2015): (i) propagate fall migrants separately; (ii) avoid late stocking during the year
Assist NAFA to improve regulation enforcement (2010 - 2015): (i) involving local fishermen communities; (ii) include in long-term contracts with private hatcheries
guarding of fishing sites
Sixths International Symposium on Sturgeon – Wuhan / China: 26 - 29 Oct. 2009
Acknowledgments:
Research funded by projects:
DanStur (348,000 € / 2006 - 2008 ) – project 120 / 2006 - CEEX Programme - Romanian Research Agency
BestCombat (1.234 million € / 2009 - 2011) – project 112231 / 2009 - Norwegian Cooperation Programme for Bulgaria and Romania (85%) and Romanian Ministry of Environment (15%)
The authors are grateful to Marilena & Dumitru Maereanuand to Robert Radutafor providing the fish and logistical assistance for the satellite telemetry
and to Fishermen Association Fetestifor assistance in capturing beluga sturgeons for acoustic telemetry
THANK YOU VERY MUCH FOR YOUR ATTENTION!