The Mozambique tilapia, scientific name Oreochromis mossambicus is an Oreochromis cichlid fish native to southeastern Africa.
Uninteresting colored, the Mozambique tilapia usually lives as much as a decade in its native habitats. It’s a common fish for aquaculture.
Mozambique tilapia facts
On account of human introductions, it’s now discovered in lots of tropical and subtropical habitats across the globe, the place it could turn into an invasive species due to its sturdy nature.
These similar options make it a great species for aquaculture as a result of it readily adapts to new conditions. It is named black tilapia in Colombia and as a blue kurper in South Africa.
The native Mozambique tilapia is laterally compressed and has a deep physique with lengthy dorsal fins, the entrance a part of which has spines.
Native coloration is a uninteresting greenish or yellowish, and weak banding could also be seen. Adults attain as much as 39 cm (15 in) in customary size and as much as 1.1 kg (2.Four lb).
Dimension and coloration might fluctuate in captive and naturalized populations attributable to environmental and breeding pressures. It lives as much as 11 years.
Distribution and habitat
The Mozambique tilapia is native to inland and coastal waters in southeastern Africa, from the Zambezi basin in Mozambique, Malawi, Zambia, and Zimbabwe to Bushman River in South Africa’s Japanese Cape province.
It’s threatened in its house and varies by the launched Nile tilapia. Along with competing for similar assets, the 2 readily hybridize.
This has already been documented from the Zambezi and Limpopo Rivers, and it’s anticipated that pure Mozambique tilapia ultimately will disappear from each.
In any other case it’s a remarkably sturdy and fecund fish, readily adapting to obtainable meal sources and breeding below suboptimal situations.
Though primarily a fish of contemporary and brackish waters, it could stay in saltwater, and even in hypersaline situations the place the salinity may be about thrice as excessive as seawater.
Among others, it happens in rivers, streams, canals, ponds, lakes, swamps, and estuaries, though it usually avoids fast-flowing waters, waters at excessive altitudes, and the open sea. It inhabits waters that vary from 17 to 35 °C (63–95 °F).
The Mozambique tilapia or hybrids involving this species and different tilapia are invasive in lots of components of the world outdoors their native vary, having escaped from aquaculture or been intentionally launched to manage mosquitoes.
The Mozambique tilapia has been nominated by the Invasive Species Specialist Group as one of many 100 worst invasive species on the planet.
It might probably hurt native fish populations by way of competitors for meals and nesting houses, in addition to by straight consuming small fish.
In Hawaii, striped mullet Mugil cephalus is threatened due to the introduction of this species. The inhabitants of hybrid Mozambique tilapia x Wami tilapia in California’s Salton Sea may additionally be chargeable for the decline of the desert pupfish, Cyprinodon macularius.
Mozambique tilapia are omnivorous. They’ll devour detritus, diatoms, invertebrates, small fry, and vegetation starting from macroalgae to rooted crops. This broad food regimen helps the species thrive in numerous places.
On account of their sturdy nature, Mozambique tilapias usually over-colonize the habitat round them, ultimately turning into probably the most considerable species in a selected space. When over-crowding occurs and assets get scarce, adults will typically cannibalize the younger for extra vitamins.
Mozambique tilapia, like different fish reminiscent of Nile tilapia and trout, are opportunistic omnivores and can feed on algae, plant matter, natural particles, small invertebrates, and different fish.
Feeding patterns fluctuate relying on which meals supply is probably the most considerable and probably the most accessible on the time. In captivity,
Mozambique tilapias have been identified to learn to feed themselves utilizing demand feeders. Throughout business feeding, the fish might energetically bounce out of the water for meals.
Communication and aggression
Urine in Mozambique tilapias, like many freshwater fish species, acts as a vector for communication amongst people.
Hormones and pheromones launched with urine by the fish usually have an effect on the conduct and physiology of alternative intercourse. Dominant males sign females by way of the usage of a urinary odorant.
Additional research has urged that females reply to the ratio of chemical compounds inside the urine, versus the odor itself.
Nonetheless, females are identified to have the ability to distinguish between hierarchical rank and dominant vs. subordinate males by way of chemical compounds in urine.
In step one within the reproductive cycle for Mozambique tilapia, males excavate a nest into which a feminine can lay her eggs.
After the eggs are laid, the male fertilizes them. Then the feminine shops the eggs in her mouth till the fry hatch; this act is named mouthbrooding.
One of many most important causes behind the aggressive actions of Mozambique tilapias is entry to reproductive mates.
The designation of Mozambique tilapias as an invasive species rests on their life-history traits:
Tilapias exhibit excessive ranges of parental care in addition to the capability to spawn a number of broods by way of a prolonged reproductive season, each contributing to their success in various environments.
Within the lek system, males congregate and show themselves to draw females for matings. Thus, mating success is very skewed in the direction of dominant males, who are typically bigger, extra aggressive, and simpler at defending territories. Dominant males additionally construct bigger nests for the spawn.
Throughout courtship rituals, acoustic communication is broadly utilized by the males to draw females. Research has proven that females are drawn to dominant males who produce decrease peak frequencies in addition to increased pulse charges.
On the finish of mating, males guard the nest whereas females take each the eggs and the sperm into their mouth.
On account of this, Mozambique tilapias can occupy many niches throughout spawning for the reason that younger may be transported within the mouth. These proficient reproductive methods will be the trigger behind their invasive tendencies.
One of many prices related to this synchronization is the rise in competitors amongst males, that are already excessive on the dominance hierarchy.
In consequence, completely different mating ways have developed in these species. Males might mimic females and sneak copy makes an attempt when the dominant male is occupied.
Likewise, one other technique for males is to exist as a floater, traveling between territories in an try to discover a mate. Nonetheless, it’s the dominant males who have got the best reproductive benefit.
Sometimes, Mozambique tilapias, like all species belonging to the genus Oreochromis and species like Astatotilapia burtoni, are maternal mouthbrooders, which means that spawn is incubated and raised within the mouth of the mom.
Parental care is, subsequently, virtually unique to the feminine. Males do contribute by offering nests for the spawn earlier than incubation, however, the vitality prices related to nest manufacturing are low relative to mouthbrooding.
In comparison with nonmouthbrooders, each mouthbrooding and rising a brand new clutch of eggs will not be energetically possible. Thus, Mozambique tilapias arrest oocyte development throughout mouthbrooding to preserve vitality.
Even with oocyte arrest, females that mouthbrooding takes vital prices in physique weight, vitality, and low health. Therefore, the parental-offspring battle is seen by way of the prices and advantages to the dad and mom and the younger.
A mother caring for her offspring carries the price of lowering her personal particular person health. Not like most fish, Mozambique tilapias exhibit a prolonged maternal care interval believed to permit social bonds to be fashioned.
Use in aquaculture
Mozambique tilapia are hardy people which can be simple to boost and harvest, making them a great aquacultural species.
They have got a gentle, white flesh that’s interesting to customers. This species constitutes about 4% of the full tilapia aquaculture manufacturing worldwide, however, is extra generally hybridized with different tilapia species.
Tilapia are very prone to illnesses reminiscent of whirling illness and ich. Mozambique tilapia are proof against large forms of water high-quality points and air pollution ranges.
Due to these talents, they’ve been used as bioassay organisms to generate metallic toxicity knowledge for danger assessments of native freshwater species in South Africa rivers.