Essay Example on Freshwater fishkeeping is the more popular area of the Hobby









This is evident because most pet stores contain some variety of freshwater fish Most freshwater aquaria are community tanks meaning they contain many different species of fish It is also common to have a single species breeding aquarium A more difficult but equally popular type of aquarium is creating aquascapes using live aquatic plants and fish Freshwater aquarium fish can come from many different locations around the world The most common areas these species come from are the Amazon River basin parts of Asian countries and throughout Africa For the purposes of this paper a common type of freshwater aquarium fish are cichlids These fish come from Lake Victoria Lake Malawi and Lake Tanganyika of eastern Africa as well as the Amazon River basin Generally these various species are easy to breed and care for The only difficulty is with choosing the appropriate community of fish because they can be aggressive The freshwater aquarium trade is a very large market Species come from all over the world One type of fish that is the most popular are cichlids Cichlids are one of the largest vertebrate families in the world 

They are most diverse in Africa and South America Africa by far contains the largest amount but the actual number of species is unknown with estimates varying between 2 000 and 3 000 Carleton 2009 Cichlids species sizes range from as small as 2 5 cm to about 1 m in length Many cichlids play vital roles in things other than the aquarium hobby Tilapia for example are important food fish The most popular aquarium fish come from South American and are called angelfish oscars and discus Cichlids have the largest number of endangered species among vertebrate families Carleton 2009 Cichlids have evolved rapidly into a large number of closely related and diverse species within the large lakes of Tanganyika Victoria Malawi Cichlids are found mostly at shallow depths with a few exceptions Lake Victoria is one of Africa's great lakes Lake Victoria occupies a shallow depression in Africa so the average depth is only about 150 feet The lake contains hundreds of cichlid species Lake Victoria used to be very rich in fish but many of these became extinct during the last 50 years Wolfshaar et al 2014 The main group of cichlids in Lake Victoria are the haplochromine cichlids The lake contains more species than any other lake in the world other than Lake Malawi The haplochromines are also part of several smaller lakes nearby have some sort of connection to Lake Victoria and are relatively shallow Katunzi et al 2010 Lake Kyoga is a good example of a lake that was easily accessible to Victoria cichlids However due to the introduction of invasive species in this lake and Lake Victoria haplochromines have become increasing hard to find During the 1950 s Nile perch were introduced into Lake Victoria 

This species of fish can grow to be about six feet long The decision was made to introduce this fish in order to increase the amount of fish that could be caught for consumption Wolfshaar et al 2014 Before about 1995 Lake Victoria supported Africa's largest inland fishery Haplochromines and other native species continued to dominate fisheries until the 1970 s van Zwieten et al 2016 After this point there was a strong shift towards the catch of non native Nile perch At the peak of catching Nile perch in the early 1990's over 500 000 tons were caught annually However these numbers have declined significantly in the years to follow because of possible overfishing As with most invasive species the expected results of introducing the Nile perch did not go well for the haplochromines and ecology of the lake As a result of predation by the Nile perch many changes to the lakes ecosystem happened It is estimated that at least about 40 percent of Lake Victoria haplochromines have become extinct over the last 50 years or so van Zwieten et al 2016 It was feared that this number was even higher but several species that were feared extinct have been rediscovered after the Nile perch started to decline in the 1990 s Another impact the Nile perch had on the overall ecology of the lake was an alteration in the food chain This decreased the number of algae eating fish found in the lake and allowed for the algae to grow at an alarming rate van Zwieten et al 2016 The increasing amounts of algae increased the amount of dead plant material that falls to the deeper portions of the lake before decomposing The process of decomposition reduces the amount of oxygen in the area Without oxygen fish cannot exist in the deeper parts of the lake 

This essentially forced all life to exist within a narrow range of depth Haplochromines have been adapting to the changing ecology of Lake Victoria Some examples of adaptations include a larger gill area for oxygen poor water changes in the feeding apparatus and changes to the eyes Brawand et al 2014 Some of the threatened Lake Victoria cichlid species have populations located in zoos public aquaria and among private aquarists There are even a few species that are extinct in the wild and only found in captivity The steep decline in the haplochromines of Lake Victoria has led to them becoming a rarity in the aquarium hobby Most haplochromine are hard to find aside from one or two species that are thriving in the lake or have been bread in abundance The literature has not totally agreed upon a solid reason for the demise of the haplochromine cichlids although human involvement has proven to be the overall factor van Zwieten et al 2016 The next and most important step is to decide what to do about saving the species we have and preserving the ecology of Lake Victoria

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