Some animals (mainly fish) in the ocean migrate regularly back and forth along certain routes because of spawning, feeding, or seasonal changes. Also known as backward swimming.

Migration is a special form of fish movement, is the active, regular, directional, clustered, species-specific horizontal movement of some fish. Migration is also a periodic movement that repeats itself annually as each part of the fish life cycle passes.

Through migration, the fish change the living waters of each life period in order to meet the needs of the living conditions in different life periods, and successfully complete the important life activities in the life history. The distance of migration varies with species, and some species travel thousands of kilometers in search of suitable external conditions and specific spawning sites.

Expanded Information:

Migratory Classification:

1. Reproductive Migrations

Based on the behavior of most of the fishes in their migrations, they are generally classified as reproductive migrations. behavior, generally can be divided into reproductive migration, bait migration and seasonal migration. For example, some fish in the process of gonadal maturation and development, each year in a certain period of time clusters, and according to a certain route to the coast, estuaries, deep sea or upstream to the river and other suitable places for spawning, known as reproductive migration.

2, bait migration

Some fish in the fattening stage often swim in groups to the bait-rich places to ingest food, this search for food migration, known as bait migration. For example, after spawning in Bohai Bay, small yellowtail, before returning to the deep-sea overwintering site, to be in the vicinity of the spawning site and return to the overwintering site on the way, to seek food more places to feed.

3, seasonal migration

Some fish with the change of water temperature in different seasons, often in groups to the place suitable for their lives, this migration with the change of the season, known as seasonal migration. For example, cod swim to the north in spring and summer, and to the south in late fall.

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