Four-spined stickleback

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Four-spined stickleback
Four-spined stickleback (Apeltes quadracus)

Four-spined stickleback ( Apeltes quadracus )

Systematics
Order : Perch-like (Perciformes)
Subordination : Cottoidei
Partial order : Sticklebacks (Gasterosteales)
Family : Sticklebacks (Gasterosteidae)
Genre : Apeltes
Type : Four-spined stickleback
Scientific name of the  genus
Apeltes
De Kay , 1842
Scientific name of the  species
Apeltes quadracus
( Mitchill , 1815)

The four- pronged stickleback ( Apeltes quadracus ) is a fish that mainly lives in brackish water .

Originally assigned to the genus Gasterosteus , the four-pronged stickleback has such a large number of individualities in form and behavior that it was raised to the rank of a genus of its own.

distribution and habitat

The four-spined stickleback is mainly found in brackish river mouths, where it prefers quiet areas with dense vegetation. Populations in salt or pure fresh water are possible, but rare.

The distribution area is limited to the east coast of North America.

features

With a maximum length of 6 cm, this type of stickleback remains relatively small.

The skin of the four-pronged stickleback is bare, which means that, unlike most other stickleback species , it has no signage with bone plates.

On the back there are 4 slender spines (rarely 1 to 3) in front of the soft dorsal fin. The last of these spines stands immediately in front of the dorsal fin, and there is a clear gap between it and the front spines.

The comparatively weak protection against predators due to the lack of signage and the fragile dorsal spines is also indicated by the generic name ( Apeltes - the defenseless ).

The body has a brown-olive basic color, the back is darker and the underside is lighter. Above it is a dark brown pattern of spots. A light stripe runs along the sidelines. The male lacks a distinctive breeding dress, only the ventral spines take on a dark red color (orange in the female) and the markings on the head are more prominent.

Number of fin rays :

  • Dorsal 1 IV (I-VII)
  • Dorsal 2 9-14
  • Anal I / 7-11
  • Pectorals 11 (12)
  • Ventral I / 2
  • Caudal 12

behavior

The main source of food for the four-spined stickleback is small arthropods , but it also acts as a "cleaner fish" and collects parasites from other fish's skin.

Due to its weak defensive armament, it immediately flees into vegetation in dangerous situations and is also able to hide in the muddy ground. Otherwise he is relatively shy.

The spawning season lasts from May to August. The very small nest built by the male is cup-shaped and is hung in or leaned against plants. When defending the territory, the four-spined stickleback is less aggressive than its relatives from the genus Gasterosteus . During courtship, the “zigzag dance” known from the three-spined stickleback is missing , instead the male leads his partner in a spiral path to the nest. During spawning, the male touches the flanks of the female more often. If the clutch is inseminated, the female is driven away. After a while, the male repairs the nest damaged during spawning, or builds another one on its roof. In this way, several “floors” with clutches can arise during subsequent spawning acts. The male supplies the clutch with oxygen by creating a flow of water by sucking the mouth - in contrast to the other stickleback species, which do this by ventilating with the pectoral fins. The brood hatches after about a week. The male does not bring back larvae that have fallen from the nest.

The four-pronged stickleback is short-lived, the males are 1 year old, the females at most 3 years old.

literature

  • Hans-Joachim Paepke: The sticklebacks: Gasterosteidae , Westarp Sciences, Magdeburg 1996, ISBN 3-89432-492-9

Web links