Even in a net of trawled fish the presence of a smelt is easy to recognize. Its cucumber aroma is very potent and has made it a popular bait with pike anglers.
The smelt’s body shape is similar to that of the salmon and trout but, because of slight differences in its anatomy, it appears in a separate family — the Osmereidae. This group includes ten other species – the capelin is one – that mostly inhabit North American coastal waters, estuaries and areas of low salinity.
Other than small trout or salmon, there are very few fish with which the smelt can be confused. Like salmonids, it has an adipose fin on the back between the dorsal fin and the tail.
Its head is scaleless and its fragile body scales are easily dislodged. The mouth is large, with numerous teeth in the jaws and palate and on the tongue.
Smelt spawn in the spring, usually moving into the upper part of river estuaries where the water is brackish and the bottom is gravel or coarse sand. The eggs sink to the bottom and stick to stones or river bed plants. Many of them break free, then wash up and down with the tides for a while, before hatching.
The adults leave the estuary after spawning but the young fish stay in the river until the following winter.
These fish feed heavily on crustaceans throughout their lives. The young eat minute water-flea-like copepods which are abundant in unpolluted tidal rivers, while the larger fish feed on estuarine amphipods (including freshwater shrimps). They also eat gobies, sprats and small herring.
Smelt live in low salinity areas and can adapt to life in slightly brackish or even fresh water. In Scandinavia extremely small smelt survive in a number of landlocked lowland lakes.
Unfortunately they have proved to be vulnerable both to changes in water quality and to the introduction of other fish.
River Thames return
The fish’s estuarine habitat has left it vulnerable to pollution in British and continental European rivers. In the Thames it became rare during the years of pollution, though it was always present in small numbers at the seaward end of the estuary.
Once the river had been cleaned up enough, it quickly re-established itself and is now present in large numbers. However, the stocks still fluctuate depending on the survival success of the young smelt. Poor weather conditions and commercial overfishing also contribute to a ‘bad’ smelt year.
Because of its size, the smelt does not receive much attention from anglers but it does get caught in herring trawls. It can be taken on light tackle using a small worm or fly. In some areas it is eaten both fresh and smoked. It is said to taste quite like sprat -but it certainly doesn’t smell like one.