Stats biolog. cand. mag. K. Larsen
Head, Salmon and Freshwater Fisheries Division
Danish Institute of Marine and Fisheries Research
Eels are present in practically all types of Danish inland waters: lakes, ponds, marl pits, peat pits, rivers, brooks, canals and ditches. Furthermore they are present in all coastal waters. Silver eels from the Baltic area are heavily exploited during their migration through the Sound and the Belts.
The gears used in inland waters vary much from place to place, being adapted to suit local conditions. All of it can however be traced back to a few basic types.
Pound nets for silver and yellow eel are used on the big commercially managed lakes. In these lakes this gear also serves the function of reducing the competitors for the food of eel, first of all bream, but often also small perch, ruffe and roach. The leaders for these pound nets may be up to 1 000 m and more in length depending on the slope of the bottom, but more usually they are located close to the banks e.g. in continuation of a point or a foreland) and extend only 100–150 m into the lake. Leaders may be supported by floats or mounted on poles. In the smaller bodies of water such as marl pits or peat pits, where commercial eel fishing normally does not take place, such large gear is not employed, neither is it used in running waters.
Fyke nets occur in two forms: the normal type fyke mounted on poles and the small, movable fykes (e.g. summer fykes). The latter consist of two small fykes facing each other and connected by a leader. They are stretched apart by being anchored by means of two stones or two poles fastened one at each end. A number of units are often combined together to form long chains. The large eel fykes are used by commercial fishermen mainly to catch yellow eels in lakes. The small summer fykes are also used to catch both yellow and silver eels in small water bodies, both by commercial fishermen and also by part-time fishermen and sportsfishermen.
Fykes on poles are used commercially in bigger streams, mainly for silver eel, in which case the entrance is turned upstream. In streams where yellow eels ascend the river from coastal waters in October-November the fykes are turned so that the entrance faces downstream after the silver eel migration has ended. In the spring when these yellow eels descend again (together with some belated silver eels) the fykes are turned again so that the opening faces upstream. Small fykes (or traps), often made of wire netting, are used in small streams to catch silver eels.
Trawl fishing takes place only in large lakes to catch yellow eels, especially in spring when eel prices are sufficiently high to warrant this rather expensive fishing method. Trawling is also undertaken to reduce the number of competitors for the food of eel.
Beach seines are used to a small extent, principally in medium or small lakes to catch yellow eels during the summer.
Longlines, like eel trawls and eel seines, are rather labour-consuming gear, are commercially used only to a small extent for the capture of the yellow eel and mainly early in the fishing season. In sport fishing, however, fishing with longlines (mounted with 50–100 hooks) is very commonly used in all kinds of stagnant waters, though sometimes also in bigger streams and canals.
Angling with only 1–3 hooks per line, used under the constant supervision of the fishermen, is practised only in sport fishing.
Bobbing is a special way of angling, used by sport fishermen in bigger streams, especially in Jutland. The bob consists of a cotton or nylon line, 1–2 m long, on which earthworms are threaded. The line is then twisted into a ball which is suitably weighted, and is lowered down to the bottom. When the eel bites into the bunch of worms the gear is gently hauled. The teeth of the eel are then caught by the fine threads of the line, so it can be landed into the boat or on to the bank.
Eel traps for the capture of descending silver eels are in use in several streams; most often they are incorporated with water mills. They may however be permitted also in the outlet from lakes and smaller water bodies where the fishery proprietor intends to exploit the eel stock in a rational way (i.e. by reduction of the competitors for the food of the eels and by the liberation of elvers and small eels up to 30 cm).
Eel-spears, eel-forks and scoop-nets are prohibited in Danish inland waters. This also applies to fishing with electricity, poison, explosives or by draining. These prohibitions, however, do not apply to waters which are the property of one fishery proprietor only and without inlet and outlet.
McGrath expressed interest in the practice of reversing the direction of a set of fyke nets to trap the upstream run of yellow eels in autumn.
Larsen - this takes place only in Limfjord and on the west coast.
Deelder - eels in Waddensee live amongst mussels and try to move into fresh water in autumn; they apparently move toward fresh water for hibernation.
Vickers - In River Bann in spring there is a build-up of yellow eels at the downstream entrance of salmon pass.
McGrath - In River Erne at Ballyshannon an elver pass had been built in the cross walls of a salmon pass consisting of a slot filled with large stones through which it was expected elvers would make their way upstream. It was discovered that in addition to elvers trying to make their way upstream there was also a run of larger-sized eels which became stuck in the stones.
O'Leary - In the River Shannon, eels at 60 per lb had been recorded going upstream through a salmon fish pass 16 miles upstream of salt water; their length/weight curve coincides with that of German eels.
McGrath asks for reason for prohibition of spear-fishing.
Larsen - due to pressure from sports fishermen.
McGrath - do pound nets conflict with sport fishing?
Larsen - sport fishing takes secondary place in these fisheries.
O'Leary - are eels in hibernation in spring?
Larsen - activity begins at temperatures from 9° to 10°C.