Fecundity can be defined as "the number of ova that are likely to be laid by a fish during the spawning season". The number of eggs produced by a fish differs in different species, and depends on the size and age of the fish.
It may also differ in different races of the same species. Thus, fecundity is a measure of the reproductive capacity of a female fish, and is an adaptation to various conditions of the environment. It can be estimated by any of the following methods:. The fecundity of a number of species has been studied by several investigators.
Fecundity of Cirrhina mrigala varies from 75, to 11, 23, when the length ranges from — mm in length Hanumantha Rao, In Labeo gonius ranging between — mm, the fecundity varies from 47, to 3,80, Joshi and Khanna, , but according to Chondar the values are 2,73, to 5,39, in the fish ranging from — mm in length.
The differences in the values are possibly due to the collection from different habitats. Fecundity of the fish is closely related to the fish length and weight. A straight line relationship has been observed between the fecundity and the fish length, and the fecundity and fish weight in a number of species. Knowledge of the fecundity of fish is useful in fishery management and the information regarding the possible number of eggs and fry likely to be produced can be used for selecting the fish of high productivity for fish culture.
Some species of fishes exhibit well marked sexual dimorphism. In the Chondrichthyes , the eggs are fertilised within the body of the female and the males are provided with claspers or myxopterygia for transferring the sperms into the body of the female. Among teleosts, an intromittent copulatory organ is present only in those species like Mystus seenghala in which a conical genital papilla is present and fertilisation is external.
In Cyprinodonts eg Gambusia the vas deferens is produced into a tube up to the end to the interior rays of the anal fin. In the Poecillidae also the males are provided with complicated intromittent organ developed from modified anal fin rays, ending in curved hooks, spines and barbs. The male four-eyed fish, Anableps , is also provided with a special tube for copulation. In all these fishes, the fertilised ova are retained within the body of the female and young ones are born. In several species of fishes, the sexual differences are not related with copulation between male and female, and are generally well marked during spawning season.
In most of the teleosts, the females are larger in size with enlarged rounded belly during the breeding season. A common secondary sexual character is the brighter colour of the body and fins in the male as in Cyprinodontidae , Cichilidae , Labyrinthidae and Labridae. In a number of Cyprinids, the male becomes more brighter in colour during the breeding season. The male Bow-fin Amia has a characteristic black spot at the base of the caudal fin.
Some species show differences in the shape of their fins and the rays may be prolonged to from long feelers in the male.
In some cat fishes of the family Loricaridae, the sexes differ in the shape of their snout, mouth, lips and in the development of bristles on their head. In the male sword-fish Xiphophorus the lower lobe of the caudal fin is drawn out to form a long blade like structure. The male of many cyprinids develop horny tubercles on the head and body, especially during breeding season. In some Gobies and Blenies, the male possess enlarged canines.
The courtship of the female by the male consists in swimming merry go round fashion in her vicinity during which the male exhibits his brilliant colours, this is beautifully exhibited by some species as the Siamese much excited during the breeding season, that they fight with other males inflicting considerable damage to one another. The males of certain Gobies also fight with each other and the victorious one shows its bright colours to the female.
Many fishes do not care for their eggs and leave the spawning grounds after fertilisation. But some species have evolved various methods to ensure proper development of the eggs which may be protected by one or both the sexes. Some fishes prepare crude nests for egg lying. At first a suitable place for preparing the nest is selected and some species defend the place till death. Males of many species like the Darters Etheostoma sun fishes and the Cichilids, prepare a shallow basin-like nest and all stones and pebbles are carefully removed from its bottom.
The eggs are laid in the nest and the male after fertilising them keeps guard over them till the young ones are hatched. A few species, however, leave the nests unprotected. Some fresh water fishes prepare a nest by clearing space among aquatic vegetation.
The African lung fish Protopterus prepares a simple nest in the form of deep hole in swampy places along the river banks. The male prepares the nest and after spawning keeps guard over it, occasionally aerating the water by his slow body movements. The South American lung fish Lepidosiren , also prepares a nest in the form of a burrow in swampy places and the male develops highly vascularised filaments on the pelvic fins, which probably serve to secrete oxygen into the surrounding water.
The male Bowfin Amia prepares a crude circular nest among aquatic vegetation. The fertilised eggs are then protected by the male who keeps guard over the nest till, the young ones are hatched.
The young ones are allowed to leave the nest in a body under the protection of the father. Both the male and the female of some cat fishes of North America Amiuridae prepare a crude nest in the mud for egg lying. The nest is sometimes provided with a protective cover of logs, stones etc. The male Gasterosteus aculeatus , prepares an elaborate nest before courtship is begun. He selects a suitable place among the aquatic plants where water flows regularly but not swiftly.
He then collects plant material which is pressed into a clear area of the nest. A sticky substance is produced by the kidneys of the male and serves to join the plant pieces together. When sufficient amount of the plant material is collected, the male burrows through its centre, thus making a small tunnel, through which he brings a ripe female for egg lying. After the eggs have been fertilised, the female leaves the eggs and the male keeps guard over it. In the early stages of the development, the male "fans" the developing embryos by sending a current water through the nest.
Later, the male stops the fanning activities and keeps close watch over the brood, not allowing any young one to go astray. Many of the Labyrinth fishes prepare a nest by blowing bubbles of air and sticky mucus. These adhere forming a floating mass of foam on the surface of water. The male fighting fish, Betta, also prepare a nest in the same way. The fertilised eggs are collected by the male in his mouth who gives them a coating of mucus and sticks them to the lower surface of the foamy nest. The nest is then protected by the male.
The male paradise fish Macropodus , also prepare a similar foamy nest but in this species the eggs are lighter than water, and rise to the nest without the active participation of the father. The European Bitterling, Rhodeus , takes extra care for the protection of eggs. When the female is ready to spawn, the oviduct extends out to form a long tube acting as an ovipositor which is used to deposit the eggs within the valves of the fresh water mussel.
The male fertilises the eggs as they are laid. After hatching, the fry leave the host and thus remain well protected from the enemies. In some species, eggs develop within the mouth of the parents. In many Cichilids, the female carries the eggs in her mouth.
After hatching also, the young fry do not leave the shelter for some time and swim about in water very near the mouth, so that they can return to it in case of danger. In the cat fish, Aureus , the male carries the eggs and young one in his mouth, who does not take food during this period.
The Butter fish Pholis rolls the eggs into a rounded ball and then one of them remains on guard by coiling round it. It is not definitely known whether the male or the female or the both take part in protecting the eggs in this way.
A cat fish, Platystacus , a cat fish of Brazil exhibits an interesting phenomenon of parental care. The skin at the lower surface female becomes soft and spongy and it presses the body against the eggs so that each one of them get attached to the skin by a small, stalked cup. The eggs remain fixed in this position till hatching.
In the Pipe fish Syngnathus and the sea horse Hippocampus the fertilised eggs are transferred by the female into the brood pouch of the male who carries them till the time of hatching. Finally, highest degree of parental care is exhibited by those species which are viviparous and produce young one.
Many marine fishes migrate to the rivers for spawning. These are called anadromous fishes and include Lamprey Petromyzon , Salmon and hilsa. Most of these fishes produce a very large number of eggs that are left uncared for. They ascend the rivers during the breeding season and on entering the fresh water give up feeding and lose weight.
During spawning they change colour and their fairly dull exterior changes to bright oranges and bright greens. They like to spawn in gravel or pebble areas when the water is between Degrees C.
Bream are famous for having very obvious tubercles white bumps on their head at spawning time and the temperature they begin spawning various quite a lot ranging between degrees. They are another species that likes shallow, weedy areas and they will spawn more than once, often with an interval of about a week between sessions.
The males get very territorial during spawning and will even attack lures intended for perch quite viciously on occasion. Bream will migrate huge distances 60Km plus to visit historic spawning areas, often swimming past very similar habitat to get to where generations of bream have spawned in years past. Most of the information above is gleaned from exprience, other anglers and a couple of books which I can highly reccomend: Freshwater Fishes in Britain was published in by Harley Books and includes contributions from many Environment Agency Fisheries staff that I have had the pleasure to work with while running Angling Trust Regional Fisheries Forums right round the country, they include Jon Shelley, Graeme Peirson, Paul Frear and Matt Carter.
Skip to content. PIKE Pike like to spawn in shallow, weedy water when the water temperature reaches around 9 degrees C which means that they are one of the first coarse fish species to spawn and it normally takes place between February — May depending on latitude and weather conditions. The author with a pike female pike from Esthwaite in the Lake District. PERCH Perch, like pike, are also early spawners, but they like the water to be a little warmer at around 13 degrees C. A River Thames perch caught on the first day of the season a few years ago.
DACE Dace are one of the species that you are least likely to see spawning as they seem to prefer to lay their eggs at night, like perch they usually spawn when the water is around degrees C, but unlike perch they deposit their eggs in gravel. CHUB Chub are gravel spawners and congregate in large numbers, often in small feeder streams where there are good gravels, high oxygen levels and warm temperatures. Barbel love to spawn on gravel in well oxygenated water.
CARP Carp are one of the easiest fish to spot spawning as they love to thrash about in the shallow weedy edges of lakes and rivers and generally make their presence well known. A few weeks before this picture was taken there were spawning carp crashing about in the shallow water under the trees in the background.
Once you know what freshwater species you want to target and where you want to go, you can make an educated decision on when to plan your trip based on a few key factors. Water temperature: Fish spawning times will vary for different species and can also vary depending on the size and depth of a waterway.
As an example, largemouth bass prefer water temperatures between degrees for spawning, while bluegill spawn when water temperatures are in the degree range. Size and depth of waterway: Keep in mind that not all areas of a large lake will reach the desired spawning temperature range in a uniform manner. This means that fish inhabiting different areas of a large lake may spawn at different times. In the case of the largemouth bass, longer periods of daylight not only heat the water, but bass eggs need sunlight to hatch.
Rainfall or current: An increase in rainfall can create additional current in a waterway, which can delay spawning activity. Stable water levels along with stable water temperatures are preferred. Sign Up. Fishing , How to , Freshwater.
Read More. Go To Fish Identifier. First Name Required. Differences between the sexes are most apparent near spawning time, when the females lay their eggs and males fertilize and often guard the nests, which is most often in the spring or early summer, depending on the species. Give a Gift Subscriber Services.
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