Mahseer is the edible fishes from the genus Barbus, and from the carp family Cyprinidae. The common names used for the Mahseer fishes genera are Tor, Neolissochilus, Naziritor and Parator.
The mahseer fishes are widely found in freshwater rivers and lakes of India and Southeastern Asia. These fishes are widely spread throughout the world from Vietnam in the north and China in the south, through Cambodia, Laos, Malaysia, Thailand, Indonesia, and across southern Asia including Sri Lanka, Indian Peninsula, Afghanistan, and Pakistan.
Mahseer has thick scales, large powerful jaws, and protrusible. Mahseer belongs to the bottom feed species as their lips adapted at the bottom for taking its feed and they are growing fleshy. This mahseer can attain a maximum size of about 90kgs with a 2-meter height. Mahseer species are widespread over the Indus river.
Mahseer fish in India are commercially important game fish. They are highly esteemed food fish. The mahseer species are fetching high market prices so, they are potential candidate species for aquaculture. Many mahseer fishes are suffering to survive because of the threatened pollution, loss of habitat, overfishing, and unregulated release of artificially bred stock
The taxonomy of the mahseers still remains complicated due to their exhibiting morphological variations. They are developing strategies for Mahseer aquaculture and propagation-assisted rehabilitation of mahseer species. Mahseers can inhibit both rivers and lakes. Most of the species will choose rapid streams with rocky bottoms to ascend their breeding. Like other carps they are omnivorous, so they are can eat algae, insects, frogs, crustaceans, and other fishes. They can also take fruits as their feed.
Golden mahseer is widespread in the Himalayan region. They live in fast-moving waters. They are inhabitants in the hilly streams with stony and rocky substrates. The Golden mahseer species can live and withstand temperatures between 5°C to 25°C. These fishes are also introduced in the lakes and other large reservoirs. The Golden Mahseers are inhabited and distributed along the Himalayan foothills, Indus, Brahmaputra, and Ganga basins. They are also found in some southern river basins like Tambraparini, Balamore, Cauvery, and Kosi Rivers. These Golden mahseer fishes can migrate according to climatic conditions and their body condition. Like it migrates towards upstream during torrential monsoon conditions to find out the best spawning grounds. In their matured condition, it will stay in lowland rivers and lakes.
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Characteristics of Mahseer
The mahseer has large scales along with the lateral lines with two pairs of barbels. The male species of mahseer can be identified by their long pectoral fins with a length of 2.7 m and weigh well over 100 lbs. As the mahseers are migratory species, they start moving upstream during the rainy season. Usually, Mahseer prefers fast-flowing, clean, and oxygenated waters. Mahseers will lay eggs based on their body weight, the count of eggs is more than carps. Likewise, mahseer species choose gravel /sandy stream beds to breed and they will migrate for a considerable distance to find it’s suitable breeding grounds. The Spawning period of mahseer fishes fall between April to September, but some younger fish can spawn earlier. Mahseer species are omnivorous. They will undergo voracious appetites and enter into diets in a wide range with frogs, insects, crustaceans, algae, other fishes, and fruits from trees, etc. The mahseer fishes are termed for their sportsman’s delight and are considered as cultural and religious significance. They are very strong and agile, they are the hardest fighting freshwater sport fish in the world. Hence, its recreation is generating considerable revenue. They are also considered as the bio-indicator of river basins.
Mahi stands for fish and seer stands for tiger, as the name refers, the mahseer is the tiger among all other fishes. It is the largest fish in cyprinid and it is known to be the toughest sportfish among the freshwater species. The colour of an adult golden mahseer will have golden dorsal sides and reddish-yellow fins. Like mahseer fish, golden mahseer also contains large scales and powerful lips, which contain relatively longer barbels. Barbels represent the hair-like sensory organs found in front of the mouth.
These fishes will often choose ephemeral headwaters. Further, it produces 6,000 – 10,000 eggs per kg during its sexual productivity. Every individual will grow at 10cm annually. Most of the mahseer species have omnivorous habits. During migration, and aged fishes remain carni-omnivorous and the fishes which are less than 46 cm long follow the piscivorous characteristics.
The scientific name of Humpback mahseer is Tor remadevii. It is a charismatic fish species widely found in the Cauvery river and present in the list of endangered species. Humpback mahseer was considered as one of the world’s top 20 freshwater megafaunas. Also, they are popularly known as "Tiger of the Cauvery river". IUCN kept this species in the red lists, which needs immediate conservation. Some efforts have been taken by NGOs to retain a few of its population in the Cauvery river basin. The migratory fishes are facing more struggles due to habitat manipulation, over-harvesting, and competition from other fish species. In recent days, the taxonomy and ecology system of this species brings the attention of scientists.
Importance of Humpback Mahseer
The Humpback Mahseer was the largest mahseer on planet earth: Its largest specimen weighed with a record of 54 Kilograms and it was found in the Cauvery River.
Humpback Mahseer is the part of the Cauvery river system: Historically, these species are distributed over the upper and middle Cauvery Basins and not found elsewhere.
In 2019, the Humpback Mahseer population was marked as a critically endangered species and attached to the IUCN Red List as threatened species.
Mahseer fish in India has been considered sacred species So, from the Vedic period people conserving and protecting mahseers in the temple ponds.
Protecting mahseer habitat also benefiting other endangered species like marsh crocodile, Grizzled giant squirrel, smooth-coated otter, tiger, leopard, and the majestic.
The humpback mahseers are acting as an important bio-indicator for the health of rivers, which gives lifelines for living organisms.
Humpback Mahseers are world-famous species and they are considered as one of the finest fighting fish in the world.
Mysore Palace have trophy specimens of some of the record catches preserved by the famous taxidermists, the Van Ingen’s of Mysore
Conservation Issues For Mahseer
Since the 1850’s the translocation movements of mahseer species are observed all over India. But during that period, the identity and integrity of the species are poorly understood. This may cause unintentional issues of hybridization among the species or competition from invasive species.
The Lakes of Kumaon hills are placed as the best-documented area. Because, the fish movements, improving angling sport, or attempting to augment declining stocks are the reason. In 1858, Sir H. Ramsey stocked the mahseer from the Kumaon lakes in Uttarakhand, Nainital Lake, Bhimtal Lake, Sattal Lake, and Naukuchiatal Lake with stock from the rivers Gaula and Kali. According to the study of the Walker, the Bhimtal stocking was less successful until the second batch of fishes was introduced in 1878. This was explained in 'Angling in the Kumaon Lakes'. In 1945, Dr. Raj a fisheries development officer from the united provinces provided the report regarding the decline of mahseer fishes stocks in the lakes. And mentioned as “From all reports, these isolated lakes had hardly any fish in them before the introduction of mahseer.” This shows the misunderstanding in the history of mahseers in the lakes, as mentioned earlier by Walker as “When I first angled in Nainital Lake, in 1863 and 1864, there were comparatively few large mahsir in it
In Himachal Pradesh, The depletion rate of golden mahseer was faster, even though it was categorized under endangered species by the National Bureau of Fish Genetic Resources as early as 1992.
In general, the geographical area covered by mahseers are depending on various factors and this is mainly due to the anthropogenic distortion of rivers like multipurpose dams, construction of river valley projects, shrinking habitats, poaching, and other stock exploitation, and some invasion of other species. The intentional stocking of mahseer fishes in India is in the trans-Himalayan regions, which are taking place for several years, which are taking place for several years. Also, yearly thousands of golden mahseers are reported from the Teesta river in Sikkim and West Bengal from 2014. This was during the drive to promote angling in those regions.
Out of 47 existing species of Mahseer in the world, India had fifteen species. In that Tor remadevi is the newest identified species. Also, the species Tor moyarensis is confined in the Moyar river of Tamil Nadu.
Initiatives of WWF for Conservation of Mahseer
World wildlife fund has found that Mahseer fishes are severely dangered. Later, they convened a national meeting in New Delhi to identify the cause of problems, reviewed the current conservation initiatives, and developed many plans for conservation of mahseers and to improve the status of mahseer species in the lakes, rivers, and other freshwater resources. All the government officials, civil society groups, scientists, and other NGOs interested in the conservation of Mahseer fishes in India participated in the meeting. Also, the World wildlife fund - India conducted the Golden Mahseer survey and prepared the species management plan for 30km in the river Kosi in Uttarakhand.
Reason for Decline in Mahseer Populations
Most of the mahseer populations are in its end line. Many man-made changes and natural disasters are the reason for the decline in Mahseer populations. Various factors are listed below.
Degradation in its Habitat
Low water flow rates through these habitats.
Dams between the rivers obstructing fish migration.
Invasion of other species and competition between species.
Pollution caused by the human activities
Pollution due to agriculture and industrial activities.
Unsustainable and illegal fishing methods like poisoning and gill netting
Lack of awareness about illegal commercial fishing among the local community
Action against misusing laws.
Absence of larger conservation community for mahseer conservation.