Author: Linnaeus, 1758
Petromyzon marinus Linnaeus, 1758
Status in World Register of Marine Species:
Accepted name: Petromyzon marinus Linnaeus, 1758 (updated 2009-06-25)
Diagnosis: in addition to the characteristics given in the key, a very large sucking-disc in both sexes with an average diameter equal to at least 70% of the branchial region and 7.5-10% of the total lamprey length. In immature specimens the dorsal fins are widely separated, but are close together in spawning individuals. This species has 67-74 trunk myomeres. Spawning males, in addition to a relatively long urogenital papilla, have a large rope-like ridge extending along the back from the head to the first dorsal fin. In mature females of this and other holarctic species of lampreys the urogenital papilla is also present but it is much shorter and barely visible from the outside; in addition spawning females of all lampreys have a well-developed anal fin-like fold. Size: up to 1,200 mm, it is the largest species among lampreys.
Habitat: typically an anadromous species but in some lakes of eastern North America there are present several land-locked populations. In the sea, littoral to meso-abyssal. Food: highly parasitic species, feeding on a variety of fish and marine mammals: Balaenoptera (Japha, 1910) and Phocoena phocoena (van Utrecht, 1969). Reproduction: spawning occurs mainly in June and July in running freshwater, brooks or rivers; females deposit numerous (up to 258,874), small (less than 1 mm in diameter) eggs in nests exclusively built by males. Duration of the ammocoete stage in the case of land-locked P. marinus can be very extensive, reported to be 18 or more years (Manion and Smith, 1978) prior to metamorphosis.
Distribution: from northern Africa throughout the western Mediterranean Sea, although absent in eastern Mediterranean and Black Seas; in the North Atlantic from Portugal to the North and Baltic Seas, except the Gulf of Bothnia; along the Norwegian coast to Barents Sea; from Iceland and Labrador to Florida and the northern shore of the Gulf of Mexico (Vladykov and Kott (1980)).
Spawning: P. marinus, as all other lamprey species, spawn in running fresh waters, in brooks or rivers, and deposit eggs in 'nests'; their larvae (ammocoetes) spend several years in fresh water before completing the metamorphosis (Hussakof, 1912: 729740| Coventry, 1922 :129-137 | Applegate, 1950: 83-113).
Eggs, larvae and young stages. Vladykov, 1950, (77): 73-95, fig. 1-13 | Applegate, 1950: 71;1951: 71-90| Vladykov, 1951b, (10) :1-14; 1952, (79): 89 | Applegate and Moffett, 1955: 36 | Vladykov, 1959: 207| MacDonald, 1959a, 28: 293-298; 1959b, 18: 91-95 | Vladykov, 1960, 17: 267-288, pl. 1-12 | Piavis, 1961, 182 (61): 111-143, fig. 1-29 | Hardisty, 1969, 2 :153-166.