Platichthys solemdali
| Platichthys solemdali | ||||||||||||
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In Vääna-Jõesuu caught on the southern edge of the Gulf of Finland flounder. Probably Platichthys solemdali . |
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| Scientific name | ||||||||||||
| Platichthys solemdali | ||||||||||||
| Momigliano , Denys , Jokinen & Merilä , 2018 |
Platichthys solemdali is a flatfish from the genus of flounder ( Platichthys ), which is endemic to the Baltic Sea . It inhabits the area between Öland in the south, the western Gulf of Finland in the east and the Åland islands in the north. It is not yet known whether the species also occurs south of Öland. The fish live in brackish water of various salinity on soft and hard soils down to a depth of 50 meters. The species is the only endemic fish species in the Baltic Sea. It was described in 2018 and named after Per Solemdal (1941-2016), who discovered that the flounder populations in the Baltic Sea some " pelagic " (in the water column floating) eggs with relatively high inflation lay eggs while others with relatively little lift that sink to the ground. The common flounder ( Platichthys flesus ), which is also found in the North Sea and along almost the entire European coast, lays the pelagic eggs. The flounder, which lays eggs that sink to the bottom, wasnewly describedas Platichthys solemdali .
features
Outwardly , Platichthys solemdali hardly differs from the common flounder. The side of the eye is dark brown, gray or olive colored and patterned with reddish dots. Like many other flatfish, however , Platichthys solemdali can change its color and adapt to the subsurface. The ventral side is whitish, sometimes patterned with scattered brownish spots. In most specimens, the eyes are on the right side of the body, but on the small Estonian island of Prangli , the left-eyed specimens make up up to 50% of the population. The proportion of left-eyed specimens may vary depending on the area and over the years.
Platichthys solemdali has fewer rays in the dorsal fin (46–59 vs. 51–66) and anal fin (35–41 vs. 35–45) and the rays in the dorsal and anal fin are not streaked. Genetically, however , the two species can be clearly distinguished. The eggs of P. solemdali have a diameter of about 1 mm and only float freely in the water at a salinity between 19 and 21.5 psu , which means that they always sink to the bottom in the already less saline habitat of P. solemdali , while those of the common flounder have a diameter of 1.3 to 1.5 mm and float at a salinity of 12 to 18 psu.
Way of life
Like almost all flatfish, P. solemdali lives on the sea floor and feeds primarily on mussels and other bottom -dwelling invertebrates. Migration between deeper wintering regions and flat regions for feeding and spawning is very limited. The fish spawn from April to June near the shore at a depth of 5 to 20 m at a water temperature of around 8 ° C. Females lay up to 2 million relatively small eggs on sandy or stony ground or in underwater vegetation. Almost nothing is known about the larval phase . In Gotland, where both P. solemdali and the common flounder occur, females become sexually mature with an age of 2 to 5 years and a length of 20 to 25 cm. Males become sexually mature at 2 to 3 years of age.
supporting documents
- ↑ a b c d Paolo Momigliano, Gaël PJ Denys, Henri Jokinen and Juha Merilä: Platichthys solemdali sp. nov. (Actinopterygii, Pleuronectiformes): A New Flounder Species from the Baltic Sea. Frontiers in Marine Science. Vol. 5, item no. 225, July 11, 2018, doi: 10.3389 / fmars.2018.00225