Going For Roe-mance?: Fish Courtship Ritual And Breeding

 

Have you ever wondered how fishes mate? Or how do they lay their eggs? If you’re a ‘Dory’ and ‘Finding Nemo’ fanatic, or just simply admiring that delicious fish you ate for lunch, it most probably crossed your mind―how do fishes mate? Well, stick with us as we dive deep in a fin-tastic adventure!

The art of courtship has been mainly observed in just about every organism around the world. And yes, even those we consume (commercially, of course), like fishes! Male fishes work their ways to find their mates and breed. However, unlike the 1‘food delivery’ and ‘dancing moves’ of the male birds, or the male snake’s ‘bumping of his chin on the back of a female’s (snake) head and crawling over her’, or the male and female whales’ ‘rolling around each other, and taking a deep dive into the ocean abyss’, fishes have their own ways of courtship ritual.

Fishes, on the other hand, have varying ways depending on their specie. While it is most commonly observed as short and usually involves the male swimming around the female, showing off until he succeeds in stimulating her. For example, the courtship ritual of the Seabass family begin with the process of: First, the female enters the male territory. Second, males produce sound using their swim bladder. Next, males perform circling bouts around the females. Then, males performs fin displays, raising and lowering their dorsal, ventral, and pelvic fins. After a successful courtship, mating pairs rise off the bottom, and spawning occurs during a ventral mount with the broadcast release of sperm and eggs.  

In some species, such as the Tilapia (O. niloticus), the Oreochromis display an elaborate courtship behavior. Members of the Tilapia genus are substrate spawners. Tilapia species can be divided into three groups according to differences in their breeding behaviour; 'guarders', 'male mouth-brooders', and 'female mouth-brooders'. In 'guarder' species of Tilapia, the territory is used both for spawning and for the protection of the young. In ‘mouth-brooders’, the spawning ground provides a well-advertised meeting place for ripe fish. 3In all Oreochromis species, the male excavates a nest in the pond bottom (generally in water shallower than 3 feet). The nests are plaques of clean sand often raised on mounds; nest cleaning is done by 'mouthing', 'nosing' and 'fanning'. Females cruise over the spawning grounds singly or in small shoals; the male swims out to meet them as they enter his territory, turns and leads back to the nest. Often there is very little pre-spawning display and spawning may be complete in two to five minutes. After laying, the female collects the eggs in her mouth and leaves the spawning ground; the male remains in his territory and immediately starts courting other females. Fry remain in the females mouth through yolk sac absorption and often seek refuge in her mouth for several days after they begin to feed. 

But note, courtship rituals and behaviors can only be observed on wild fishes; those who aren’t farmed. Farmed-fishing or pisciculture involves breeding, rearing, and production of fish by artificial means―manipulation of sexually matured fish to spawn or reproduce in captivity. There are fishes such as, Pompano (Trachinotus) and Milkfish (Chanos Chanos) that are highly farmed and bred. Although Tilapia is also farmed, it is fairly easier to find and inexpensive than the  former because of lower feed cost, and ingests almost anything fish-edible. 

The importance of artificial breeding of fish is to obtain large quantities of quality hybrid fish seeds that, of course, have higher market value. And because Pompano and Milkfish are more costly than Tilapia, they are most commonly bred through artificial breeding, for commercial purposes. 5Like the very popular bangus, pompano can be cultured in marine cages.  Although it is less expensive to raise bangus, there is less competition in pompano as only fish growers raise them. In the Philippines, there are Bangus (Milkfish) and Pompano farmers that practice natural and or artificial breeding. It still requires an extensive and comprehensive study of the said fishes’ mating behavior so there are still little-to-no display and observation. 

Either way, we think that fish courtship ritual is interesting to share with you!  Follow our of-fish-ial website for more fin-teresting facts!