Tench fish, its habitats, characteristics, fishing methods and techniques.
Tench (Tinca tinca) are a widespread species of freshwater fish native to temperate Europe and Asia. Popular as an angling species, they have been introduced to a number of countries as a sport fish. Their omnivorous diet and tolerance of a wide range of environmental conditions has lead to some countries labelling tench an invasive species, due to concerns over competition with native fish. Tench are a heavy-built, thick-set fish with a small barbel at each corner of the mouth. Colour ranges from deep blackish-olive to pale golden tan, with a bright reddish eye. The body is slimy, with the small scales being covered by a thick layer of mucus. Very large specimens may reach 800mm in length and 8kg in weight.
A combination of understanding the fish and the techniques used to catch them will help you to hook more fish to the end of your line. Better knowing and understanding of the fish that you are trying to catch will make you a more successful angler, whether you are fishing for trout on a river or surfing on the beach or trolling on the open water.
The Tench (Tinca tinca) or doctor fish, also known as
Линь in Russian, is a freshwater and brackish water fish of the
Cyprinid family, Carp family found throughout Eurasia from Western Europe including the British Isles east into Asia as far as the Ob and Yenisei Rivers. It is also found in Lake Baikal. It normally inhabits slow-moving freshwater habitats, particularly lakes and lowland rivers.
The Tench is a medium-sized fish, typically attaining 60-80 cm and weighing 2-3 kg with a maximum size of about 84 cm and 8 kg. Tench have a stocky, carp-like thick shape, and the caudal peduncle is deep and short, olive-green skin, darker above and almost golden below. The caudal fin is square in shape. The other fins are distinctly rounded in shape. The head is triangular, generally averaging just 30% of a body. The snout is relatively long and the interorbital distance is broad. The mouth is terminal, oblique, and rather narrow and provided at each corner with a very small barbel. Pharyngeal teeth are in a single row, typically with either 4 or 5 on each side. In juveniles, the pharyngeal teeth may be wedge-shaped and slightly hooked at the tip. There are about 10-20 gill rakers on the first arch. The rakers are moderately long. The dorsal fin is rounded and has 6-9 soft dorsal rays. The anal fin is also rounded and has 5-9 soft rays. The caudal fin is somewhat truncate (squared).
The eyes are small and red-orange in color. Sexual dimorphism is weak, limited to the adult females having a more convex ventral profile when compared with males. Males may also possess a very thick and flattened outer ray to the ventral fins. The Tench has very small scales, which are elongated horizontally and deeply embedded in a thick skin, leaving only 1/4-1/3 of the scale exposed and making it as slippery as an
American Eel. The skin is covered with a thick layer of mucous and is extremely slimy. Lateral-line scales number 70-120.
The body is dark green on the back and greenish-brown to dark brown on the sides. The belly typically has a yellowish tinge. Body coloration may vary with habitat, ranging from almost black in shallow, muddy lakes to much lighter in running water or clear water lakes. The fins are dark gray to dark brown to black. Eyes are orange-red. An ornamental variety Golden Tench is orange-yellow or reddish.
Sexual dimorphism is evident but not pronounced. In mature males, the second unbranched ray of the pelvic fins is thickened and is accompanied by a muscular protuberance from the flank. Additionally, these fin rays are longer, reaching past the vent and extending to the anal fin.
Tench can be distinguished from native cyprinids by the combination of a single barbel at the end of each maxilla (one pair), while Common Carp has two pair, thicker body and the presence of deeply embedded, 70-120 fine scales in lateral line, 26-31 in
Crucian Carp, 40 or fewer in Common Carp. The dorsal fin is short and lacks a heavy spine-like ray, which distinguishes it from
Goldfish, and Crucian Carp. Additionally, the Tench has a squared caudal fin (as opposed to a forked one in
Common Carp and the truncated tail fin in Crucian Carp) and very small bright red eyes.
Habitat and Habits
The Tench prefers shallow, vegetated areas of
lakes and ponds, lower reaches of slow-moving
rivers, adjacent backwaters, and oxbow lakes. Larvae and juveniles inhabit areas characterized by dense aquatic vegetation. During summer months, the Tench seeks cooler temperatures by concentrating in deep holes and shaded areas. It tends to be inactive during the day, resting in favored habitats such as dense aquatic vegetation, and forages for food after dusk. The Tench is most often found in still waters with a clay or muddy substrate and abundant vegetation. This species is rare in clear waters across stony ground, and is absent altogether from fast-flowing streams. It tolerates water with a low oxygen concentration, even being found in waters where the carp cannot survive.
The Tench appears to be a relatively unselective, generalist predator of invertebrates (especially benthic organisms) in both native and introduced regions. In Ireland, 4 year or younger Tench fed primarily on plankton, whereas larger and older fish consumed mollusks, chironomids, other insects, and plankton. In Spain, cladocerans, gastropods, small crustaceans, and insect larvae and older fish preferred prey items. In Australia, Tench consumed chironomids, pulmonate gastropods, cladocerans, amphipods, ephemeropterans, and odonates. In England and France the young larvae primarily preyed on cladocerans, whereas older larvae and juveniles primarily consumed cladocerans and copepods. Older Tench in the United Kingdom ate a wide variety of benthic invertebrates, including bivalves, amphipods, isopods, trichopterans, and other insects. The diet of small Tench (6-12 cm) consisted of aquatic insect larvae, especially mayflies, damselflies, midges, and caddisflies. Larger fish consumed whatever invertebrates were available, including snails, mollusks and oligochaetes.
Males generally mature in their third year, females mature a year before. Spawning is usually occurs in summer when water temperatures reach 18-20°C. The species aggregates for spawning in shallow, usually among aquatic plants, vegetated areas where the adhesive green eggs are deposited over vegetation. The Tench is a batch spawner and will spawn over artificial substrates resembling vegetation. Fecundity increases with body mass and length. The maximum fecundity is more than 1,200,000 eggs in Eastern Europe. Fecundity can be high. In Russia, fecundity varied from 230,000-400,000 eggs. Eggs are small, 1-1.2 mm, yellow or green, and hatch in 3-8 days at 22-24 °C. Growth is rapid, and fish may reach a weight of 0.11 kg (0.25 lb) within the first year.
Large Tench may be found in gravel pits or deep, slow-moving waters with a clayey or silty bottom and lots of aquatic vegetation. They take a variety of baits but are "nibblers" and are difficult to hook. Fish over 1 kg (2 lb) in weight are very strong fighters when caught on a rod. Tench fishing is a summer pursuit, as these are warm weather fish and in winter they tend to become dormant. They vary from bronze through olive green to almost black, depending upon habitat. Golden tench have been bred selectively and in the wild they are very vulnerable to predatory birds.