r te e a n n i w o t z g l n a n i s io y - t Atlantic a h i JUV t s s ENI S e n LE r a ( f r 3 t -4 r herring e y v e i ec Jan a r D rs A ) a V m e R F o s v e A The area’s name Haringvliet A r o b D o L F N t U L refers to the past, when a T e r M s t e the Haringvliet teemed a c v r i m r O o with juvenile herring. r o F t Herring are born at sea. A p p e r The juvenile larvae then S migrate to coastal waters M g a y u and to the freshwater- A J u l n u saltwater transition zone J where they grow into adults. Subsequently, the adult herring migrate again to sea Fish migration to spawn. European From river to sea and vice versa sea sturgeon JUVEN ILE (2 -4 y In 2018, when the Haringvliet sluices will be slightly opened, the Haringvliet will again e Much effort is put into ec Jan a D rs ) securing the return of this F v e become the gateway to the rivers Rhine and Meuse. In the Haringvliet, migratory fish o b N prominent and impressive J U will then be able to acclimatize in brackish water, before continuing their journey to ) V migratory fish to Dutch s E r M t N a c a e I r L waters. Sturgeons are born y O E the river or to sea. Based on historical data, we have displayed how 16 fish species 2 1 upriver. Juvenile sturgeons - A 8 ( D A made use of the freshwater-saltwater transition zone in the Haringvliet, i.e. during p run downriver and stay U p E e r L L S I T which part of their life cycle and during which period of the year. The fish migration N a considerable time in E V M the freshwater-saltwater U g a u J y A calendar provides insight into developments that can be expected to take place after transition zone and only J l u u n J the Haringvliet sluices are opened in 2018. become adult fish at sea. Mature sturgeons run upriver during the summer to produce offspring. Spring: Autumn: All year round: migration from migration from nursery area for Atlantic sea to river river to sea juvenile fish salmon ADULT Salmon stay the greater The fish migration calendar on From July until December the In addition to being a route of part of their life cycle at ec Jan JU the inside of the leaflet features prevailing migration pattern is passage for migratory fish such D V E F N sea, but just like sturgeons v e a complex mixture of migration downstream, from the river to as salmon and sturgeon, the o b IL N E they depend on fresh water patterns. Throughout the year sea. The predominantly juvenile freshwater-saltwater transition ( 1 - 3 M fish run upstream towards the fish, which were born in the river, zone also plays an important role for their reproduction. y t a e c r a river or downstream towards the such as allis shad, twait shad, sal- as refuge and nursery area for O Throughout the year adult r s sea. From February until July, the mon, sturgeon and sea lamprey, juvenile fish. Juvenile European ) salmon run upriver to A prevailing migration pattern is migrate through the Haringvliet sprat, smelt, river lamprey, p p spawn, showing a peak from r e upstream from sea towards the to sea to forage, to grow into European seabass and herring S May to August. Juvenile river. Species such as stickleback, adults and to spawn. Before any stay sometimes for 1 to 2 years in M a g salmon, also known as y u allis shad, twait shad, sturgeon transition from fresh water to salt this brackish-water zone before A smolts, need a gradual J u l n u water and vice versa it is vital they continue their journey to J and smelt run upriver to spawn. that migratory fish can acclimati- sea or to the river. Juvenile fish freshwater-saltwater ze in an undisturbed brackish-wa- also serve as food for numerous transition in order to be ter zone, which the Haringvliet other fishspecies and birds, able to adapt to saltwater Illustrations: will provide after 2018. including migratory species. © Jeroen Helmer, ARK Natuurontwikkeling conditions. FROM SEA TO RIVER FROM RIVER TO SEA STAYING IN FRESHWATER-SALTWATER TRANSITION ZONE SOURCE: The Fish Migration Calendar has been drawn up by Bart Reeze (Buro Stroming), Martin Kroes Fish Migration Calendar (Kroes Consultancy), Willie van Emmerik (Sportvisserij Nederland) and Jaap Quak (Sportvisserij Nederland) Haringvliet based on historical and biological data. LIFE PHASE JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC EXPLANATION European eel glass eel 1-3yrs Reproduction at sea. Glass eels migrate to coastal waters and various freshwater bodies. Anguilla anguilla yellow eel 2-17yrs Grow also in the estuary and can be found all year round. adult Mature eels migrate to the sea/the ocean to reproduce. European juvenile Reproduction at sea. Juveniles migrate to shallow coastal waters until reaching freshwater river areas. flounder juvenile 2-4yrs Juveniles grow up in the estuary. Platichthys flesus adult Mature adults migrate to foraging grounds in the coastal zone and to the sea to reproduce. Three-spined juvenile 0.5yrs Reproduction in the downstream part of the river. Juveniles migrate to the estuary and coastal zone. stickleback adult Present throughout the year in estuaries and shallow coastal zones (including the Wadden sea). Gasterosteus aculeatus Migrate from the sea to the river to spawn. Thinlip mullet juvenile 9-11yrs Reproduction at sea off the coast. Juveniles live in the estuary’s shore area. Liza ramada adult Present throughout the year in the estuary. Migrate to the estuary and river during spring and in the opposite direction during autumn. Allis shad juvenile 0+yrs Reproduction on the river. Juveniles migrate to the estuary. Alosa alosa juvenile 0-1yrs Continuing their journey to the coastal zone and the sea as from October (or a year later). adult At sea / in coastal waters. Migrate upriver to reproduce. Reproduction in the freshwater area of the tidal zone or slightly more upstream. Twait shad juvenile 0+yrs Juveniles migrate to the estuary. Alosa fallax juvenile 0-1yrs Migrate immediately to the coastal zone and the sea (or a year later). adult At sea/ coastal waters. Migrate downriver to reproduce. Atlantic larva Reproduction at sea. Larvae migrate to coastal waters and the estuary. Herring juvenile 3-4yrs Nursery areas in coastal waters and estuaries. Migrate at a later stage to deeper waters / the sea. Clupea harengus adult At sea. In March-June small numbers stay in the Voordelta/Goereese Gat areas. Spawn in the midstream/downstream part of the river. Houting juvenile Juveniles go slowly downriver to the coastal zone and the estuary. Coregonus oxyrinchus juvenile 2-4yrs and adult Stay all year round in the shallow coastal zone and the brackish-water area of the estuary. Mature adults migrate upriver and downriver to reproduce. larva 3-4.5yrs Reproduction on the river and brooks. After 3-4.5 years the larvae float down the river to the estuary. River lamprey juvenile 1.5yrs Grow up further in the estuary and later at sea. Lampetra fluviatilis adult Live in estuaries, coastal waters and the open sea. Migrate to rivers and brooks to spawn. Reproduction on the river, just upstream of the tidal zone. Smelt larva Larvae grow in freshwater areas and the estuary. Osmerus eperlanus juvenile 2-3yrs and adult Grow up and live in the estuary and the coastal zone. adult Migrate upriver (and downriver) to reproduce. European sprat larva Reproduction at sea /in coastal waters, larvae float to coastal waters or estuaries. Sprattus sprattus juvenile <2yrs Nursery areas in coastal waters and estuaries. Migrating later on to deeper waters/ the sea. adult Adults stay in the estuaries during winter /older adults stay at sea. juvenile Reproduction on the river. Juveniles migrate to the estuary. European sea juvenile 2-4yrs Juveniles grow up in the estuary. sturgeon juvenile 8-12yrs Older juveniles migrate to the coastal zone and the sea where they continue their development. Acipenser sturio adult At sea. Mature adults migrate to the river to spawn. Atlantic Salmon juvenile 1-3yrs Reproduction on the river. Juveniles migrate to the sea and have a short stay in the estuary. Salmo salar adult At sea. Mature adults migrate to the river to spawn, all year round with a peak from May-August. European seabass juvenile 4-5yrs Reproduction at sea. Juveniles migrate to estuaries, harbours and lagoons (warm, shallow waters). Dicentrarchus labrax adult summer Migrate to the estuaries’ foraging sites during summer and to the sea during winter. Sea trout Reproduction at the upstream part of the rivers. Salmo trutta trutta juvenile 2-3yrs Juveniles migrate (rapidly) through the estuary towards the coast and the sea. adult In coastal waters, gathering in estuaries before migrating to the river to reproduce. Sea lamprey Petromyzon marinus juvenile 2-3yrs Reproduction in the midstream/upstream parts of the river. Juveniles migrate to the sea. adult At sea. Migrate upriver to spawn. t F o r o r m i v e s r e a t F o r o s e m a r i v e r t r f a r S e n t s s a h i t y - i o s i n a n g l t z w i o n a n t e e r Migratory fish in and around the Haringvliet Visit haringvliet.nu In 2018, the Haringvliet sluices will be slightly opened so that fish will be able to migrate again between the river and the sea.