MINHO RIVER BASIN 1St Seminar INDICANG, Rochefort, 18/05/2005 19, 20 JUNE - NANTES Minho River PORTUGAL

FINAL MEETINGMINHO RIVER BASIN 1st Seminar INDICANG, Rochefort, 18/05/2005 19, 20 JUNE - NANTES Minho River PORTUGAL

Carlos Antunes, Alfredo Oliveira, Sérgia Dias, João Coimbra Centre for Marine and Environmental Research (CIIMAR) –University of Porto

MINHO RIVER BASIN 1st Seminar INDICANG, Rochefort, 18/05/2005

LEON

Catchment area (total): 17 080 km2 International sub-basin area: 1 934 km2 Catchment area in Spain: 16 250 km2 Catchment area in Portugal: 800 km2 Total surface water area: 800 km2

International river: Spain and Portugal River spring: Spain, at “serra de Meira”, 750 m altitude. Course: 300 km, the first 230 km in Spain. The final 70 km are the border between Portugal and Spain. Geographical location

Minho River Basin: Physical caracteristics (as a unity) MINHO RIVER BASIN Altitude 1st Seminar INDICANG, Rochefort, 18/05/2005 Minho – 750 m Sil – 1 500 m

800 e os 2300 mm/ano

Air temp. 7ºC – 15ºC

600 e 850 mm/ano

MINHO RIVER BASIN Geology 1st Seminar INDICANG, Rochefort, 18/05/2005

Land ocupation: Forest - 64% Agriculture - 33% Urban and artificial areas - 2% Water - 1% Hidrography: Temp.- 9ºC - 21ºC

Estuary length – 35 Km Main tributaries: Salinity – 0,1 - 34,6 Mean monthly discharge – 834 615 dam3 Area of the sub- Name basin

Sil (1) 8000 km2 (50%) Spain Arnoya (2) 725 km2 Left bank

Neyra (3) 832 km2

Tea (4) 411 km2

Avia (5) 670 km2

Ferreira (6) 266 km2 Right bank

Ladra (7) 886 km2

Támoga (8) 233 km2 Portugal Mouro (9) 141 km2 Left bank Coura (10) 268 km2 MAIN ENVIRONMENTALMINHO CONSTRAINTS RIVER BASIN 1st Seminar INDICANG, Rochefort, 18/05/2005 TO EEL POPULATION DAMS Dam locations in Minho catchment area

SPAIN: 44 PORTUGAL: 3 NO FISH PASS(46) OR NOT WORKING(1)

FIRST DAM (80 Km))

Accessible area = 11% of total catchment area

MINHO RIVER BASIN ENVIRONMENTAL 1st Seminar INDICANG, Rochefort, 18/05/2005 CONSTRAINTS

pollution

Lugo Urban

Ponferrada Orense Industrial and Urban Urban Rio Barbaña Industrial

Rio Louro Industrial - Industrial sewage VN Cerveira - Urban sewage Industrial - Solid residues - Dilution caudal - Dams eutrofication

MINHO RIVER BASIN 1st Seminar INDICANG, Rochefort, 18/05/2005

ENVIRONMENTAL CONSTRAINTS Metals (Fe, Mn, Zn, Cu, Pb, Cr, Al, Ni, Cd)

Sediment quality Pesticidas Organoclorados (a-Lindane, b-Lindane, g-Lindane, d- Lindane, Heptacloro, AldrinR, Heptacloro Epóxido, Endosulfan, Heavy metals DDE, Dieldrin, Endrin, DDD, Endosulfan, DDT e Metoxicloro) Pesticides

MET 3

20 g) / 15 g n (

onc 10 C

0 Janeiro Abril Julho Outubro a-Lindane b-Lindane g-Lindane d-Lindane Heptac loro AldrinR Heptacloro Epóxido DDE DDT Metox ic lor o

MINHO RIVER BASIN 1st Seminar INDICANG, Rochefort, 18/05/2005 ENVIRONMENTAL CONSTRAINTS Exotic species

MOLLUSCS – 3 CRUSTACEANS – 2 FISHES – 7 BIRDS – 3 MAMMAL - 1

Micropterus salmoides Cyprinus carpio Prochambarus clarkii Corbicula fluminea

MINHO RIVER BASIN ENVIRONMENTAL 1st Seminar INDICANG, Rochefort, 18/05/2005 CONSTRAINTS Parasites

Prevalence of Anguillicola crassus (1995/96) = 15 – 87,5 % New data for 2006/07

Variação sazonal das prevalências (%) de parasitose 2005/06 100,00

80,00 Myxidium giardi 60,00 Pseudodactylogyrus 40,00 anguillae 20,00 Gnathiidae gen. sp. 0,00 Ergasilus gibbus

ra o o o e rã n rn v e to e a V u v m O in ri P

Hermida, M. et al. (2006) MINHO RIVER BASIN 1st Seminar INDICANG, Rochefort, 18/05/2005

GLASS EEL EXPLOITATION

Number of fishing licences general > 1000 glass eels = 350 – 400 fishery data declared = 50 - 60%

FISHING REGULATION (2006/07) Stow net: O1 Nov. – 30 March Hand dip net: 01 Out. – 30 March

Photograph by Eliseo Alonso

Hand-held dip net -“rapeta”

Stow net - “tela”

MINHO RIVER BASIN 1st Seminar INDICANG, Rochefort, 18/05/2005 YELLOW EEL EXPLOITATION

Fyke-nets

FISHING REGULATION (2006/07) Fyke-net: 01 Sept.-30 Nov. Baited hooks: All year Length > 20 cm

MINHO RIVER BASIN 1st Seminar INDICANG, Rochefort, 18/05/2005

n 30 To OFFICIAL DATA OF GLASS EEL CATCHES 20 FROM PORTUGAL (P) AND SPAIN (SP) IN THE MINHO RIVER (1974-2006) 10

0 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 year Average price – 300 € / Kg (2006/2007)

Portugal Spain Total

Ton 6

OFFICIAL DATA OF YELLOW EEL CATCHES 4

FROM PORTUGAL AND SPAIN IN THE 3 MINHO RIVER (1983-2006) 2

Average price – 7,5 € / Kg (2006/2007) 1

0 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 The data are underestimated. year

Portugal Spain Total MINHO RIVER BASIN 1st Seminar INDICANG, Rochefort, 18/05/2005 glass eels (g/h)

5000

4000

3000 Experimental glass eel fishery

2000

1000

0 Nov J MMJl S N JMMarMJlAOD F A J AOD F

81 82 83 00 month

100%

80%

YIELD (g/h) 60%

PIGMENTATION STAGE 40%

LENGTH AND WEIGHT 20%

ENVIRONMENTAL DATA 0% Fev Mar Abr Mai Jun Jul Jul'' Ag Set Out Nov Dez Jan Fev Mar Abr Mai Jun Jul Ag Set Out BY-CATCH COMPOSITION 00 01

VA VB VIAo VIA1 VIA2 VIA3 VIA4

MINHO RIVER BASIN 1st Seminar INDICANG, Rochefort, 18/05/2005 Glass eels and leptocephali - otolith microstructure analyses

LII

LIII

Antunes C & Tesch FW, 1997

MINHO RIVER BASIN 1st Seminar INDICANG, Rochefort, 18/05/2005

YELLOW EEL

Fyke-nets

N=470 0,9 eels/fyke-net/night

1 800 ind./ha – 77 Kg/ha

N=600 2400 ind./ha – 44 Kg/ha

800 ind./ha – 33 Kg/ha

1 600 ind./ha – 32 Kg/ha

1 400 ind./ha – 52 Kg/ha

4,5 eels/fyke-net/night 9 500 ind./ha – 383 Kg/ha Electric fishery in small tributaries

MINHO RIVER BASIN SILVER EEL 1st Seminar INDICANG, Rochefort, 18/05/2005 No historical data available

600 Average length N = 1261 500

400 Salmon ladders mm Xunta Galiza 300 Minho tributaire 200

100

0 2000 2001 2002 2003 2004 2005 year

yellow silver

MINHO RIVER BASIN Minho River 1(semi-closedst Seminar INDICANarea)G, Rochefort, 18/05/2005 4 fyke-nets in water continuously PIT tag Complete biometric data OTC Tatooing

ye ll ow / si lver ee ls 90

) 50 m c ( h t g 40 len

Mean 0 Mean± SD jan feb m ar apr m ai Mean± 1,96* SD m ont h

0,27 eel/fyke-net/night recapture - 6,25%

MINHO RIVER BASIN 1st Seminar INDICANG, Rochefort, 18/05/2005 WORK CARRIED OUT IN INDICANG PROJECT

ENVIRONMENT

• database organization in a Geographical Information System (GIS) (Hidrology, land uses, geology, dams and its characteristics). New data will loaded in the future. • water quality - 29 automatic stations (temp., pH, conduct., oxíg., turb., NH4+), 385 periodic sampling stations, international area – 8 sampling stations analysing 68 parameters (physical, chemical, bacteriological, heavy metals) • water uses (consumption, agriculture, aquaculture....)

IN THE FIELD: • complete characterization of the obstacles in the bassin (not finished) • sediment quality analysis concerning heavy metals and pesticides in Minho river estuary, including saltmarsh areas

WORK CARRIED OUT IN INDICANG PROJECT MINHO RIVER BASIN 1st Seminar INDICANG, Rochefort, 18/05/2005 EEL POPULATION

• monthly experimental glass eel fishery (biometric and pigmentation stage of glass eels data were registered, environmental data, by-catch)

• accurate fishing data from fishermen to apply in glass eel estimation entrance; it was done a first adaptation of the Loire model to Minho

• parasites (comparing actual prevalence of Anguillicola with old data); other parasites

• exotic species

• potencial predators (eg. Cormorant – Phalacrocorax carbo)

• mark – recapture studies in yellow eels

• Abundance of eel population in tributaries (electric fishery) – not finished