Parental Care in Fishes
We can define parental care as an association between parents and the offspring through which the chance of survival of young ones gets increased or any behaviour performed by parents that appears likely to improve the survival and reproduction of the young.
In the case of fishes, all fishes do not provide parental care, but in many species of fish, parental care is provided to increase the chance of survival and development of their eggs into adults.
Estimation of parental care in Fishes:
- 77 percent of fish show no parental care
- 17 percent of fishes shows care of eggs only and,
- 6 percent of fishes care for their eggs and are newly hatched young.
Various methods are adopted in fishes, in the process of parental care, in this process one and both sexes maybe get involved.
Patterns and Various Methods of Parental Care in Fishes:
- Deposition of eggs in suitable places
- The simplest form of fish parental care is hiding the eggs
- Self-made nest for deposition of eggs
- Concealing eggs and young inside or on their body
- Viviparity in some fishes
- Care of independently swimming young ones
Deposition of eggs in suitable places:
In some fish species, the eggs are deposited at their own designed suitable places. They choose places like:
- Deposition of eggs in sticking covering
- Carps are laid with special sticky coverings for attachment to each other or to stones, weeds, etc.
- Yellow perch deposits eggs in a rope-like structure, and a long floating membrane works for eggs to hold together.
- Flying fishes, garfishes, skippers, etc. secrete a sticky thread-like substance from the kidney by which eggs remain attached.
- laying eggs at suitable places
- The anadromous fishes like Acipenser, Onchorynchus, etc. lay their eggs in suitable places for spawning. They lay their eggs in pits and cover them with gravel and desert them.
- Depositions of eggs on dead shells of bivalves
- Fishes like the female of European bitterling (Rhodeus amarus), and females like the cyprinid family deposits their eggs in dead shells, water Mussels.
- scattering of eggs over aquatic plants.
- Examples of such parental care in fishes as such pikes, carp, the eggs are scattered and attached to aquatic plants.
Self-made nest for deposition of eggs:
Some species of fish prepare different types of nests for the deposition and protection of their eggs. These nests may be Basin-like, Circular nest, Hole, burrow nest, Barrel shaped to nest, Cup-shaped nest, Floating nest, or Foamy nest.
Examples of different types of nests made during parental care:
- Female Darter makes basin-like depression and deposits eggs in it. The eggs are fertilized by the male and covered by a sticky secretion from its kidney. These sticky eggs stay attached to the stone till hatching.
- The Cichlid fishes build a basin-like nest and it is guarded by both parents.
- Male Bowfin (Amia calva) makes a circular nest
- The male African lungfish (Protopterus) makes a nest in the form of a deep hole in swampy places along the river bank.
- The male Mormyrids (Gymnachus) make a floating nest in aquatic vegetation.
- The male Betta fish (Fighting fish) makes a nest by blowing bubbles of air and sticking mucus that adheres and forms a floating mass of foam on the water surface. The fertilized eggs are collected in the mouth of males. The male stays and guards the eggs and fights till death to protect them.
Concealing eggs and young inside or on their body:
Some fish species keep eggs and young in their body or mouth or brood pouches.
Example of Concealing eggs inside the body:
- in cichlids, the female keeps the fertilized eggs in their mouth.
- In Catfishes (Arius) and cardinal fishes, the male carries eggs and young ones in their mouth. During this period the male fish does not take food.
- The male Kurtus (nursery fish) of new guinea, carries eggs on the forehead, held in the cephalic hook.
- Some parents keep eggs in Brood pouches: like sea horses (Hippocampus). In sea horses, the fertilized eggs are transferred by the female into the brood pouch of the male. The brood pouch is found on the lower abdomen. For several weeks the male hippocampus provides nutrients and oxygen to the fertilized eggs.
- In male pipefishes (Syngnathus) a brood pouch is formed between two flaps of skin, on the underside of the body. The female lays eggs on these brood pouches.
Viviparity in some fishes:
This is the highest degree of parental care, found in viviparous species. Some species provide maximum protection, and internal incubation and they give birth to young ones.
Example of Viviparous parental care:
- Viviparous Elasmobranchs: Viviparity is found in most shark families. Fishes such as Scoliodon, Mustelus, etc, eggs develop in the uterus, and the mucus lining of the uterus forms fluid-filled protective compartments, for each of the embryos. Each embryo gets nourishment in the form of embruotrophe or uterine milk, from uterine tissue through the yolk sac placenta.
- Viviparous bony fishes: Teleost species like gambusia, poicilia, etc also show internal fertilization and the young one develops in the ovary but is free from its wall.
- Shiner perch fertilizes eggs in the ovarian follicle and is very soon released into the ovary cavity. These are nourished by a secretion from the ovary. The young are retained in the ovary till they become sexually mature.
Care of independently swimming young ones:
In some species, parental care does not stop with caring for eggs. In these families the fishes care for young ones, placing them in a safe place and protect from predators and enemies. For example- the families such as Gasterosteridae, Centachidae, and Ictaluridae.
You can also read:
- Scales in Fishes
- Migration in Fishes
- Scoliodon – Dogfish, Classification, and Characteristics
- Herdmania- Sea Squirts
References: Vertebrte – Kotpal text book
Thank You 🙂