Hint: These fishes are believed to make regular circuits of migration in the sea before coming to their natal rivers is the term that describes fish born in freshwater who spend most of their lives in saltwater and return to freshwater to spawn.
On the northeast Atlantic coast, a large, anadromous, ectoparasitic fish is found called sea lamprey (Petromyzon marinus).
Sea lamprey (Petromyzon marinus) is also known as the "vampire fish".
Sea lampreys from their habitat like lake or sea, they migrate up rivers to spawn. Therefore they are anadromous.
Males make the nest in the substrate of the stream with a moderately strong current and females deposit a large number of eggs in these nests. Death of the adult fish after Spawning.
From the spawning area, Larva burrows in the sand and slides bottom in water which feeds on plankton and detritus.
The larvae undergo metamorphosis after several years in freshwater habitat and allow migration of young post-metamorphic lampreys to the sea or lakes, hence starting the adult hematophagous method of feeding.
Before migrating to the sea, some lampreys start hematophagous feeding in the river where sea lamprey feeds on a wide variety of fish.
Catadromous- these are the fishes that take birth in the saltwater and in their Juvenile phase, they migrate into the freshwater where they grow into adults and then again migrate back into the sea to spawn. Include American eel, European eel, inanga, shortfin eel, longfin eel.
Potamodromous- it is migratory like Anadromous or catadromous fishes but does not spend its whole life in freshwater like them.
So, the correct answer is option (A) ”Anadromous”.
Note: A parasitic lamprey found in the Northern Atlantic oceans along the shores of Europe and North America is Petromyzon.
Migration from the sea into the freshwater for spawning is done by Anadromous fishes. They stay entirely in the freshwater and migrate upstream to spawn.