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LIVEBEARERS
LIVEBEARERS
Livebearers belong to the massive order, Cyprindontiformes and are made up of, among others,
the families Anablepidae, Goodeidae, Hemirhamphidae, and Poeciliidae. Livebearers are the most popular of
all aquarium species due to the wide availability, relatively peaceful behavior, and their colors. Livebearers
have a wide range of appearance, from the common guppy to the odd Freshwater Sting Ray (Potamotrygon sp.). Livebearers are distributed
throughout Southeast Asia, the Americas, and the Caribbean.
The eggs are fertilized internally in the female. The eggs are fertilized by the male
through a mating organ, usually a modified anal fin.
The embryos develop in one of two ways depending on the fish:
(1) In ovovivoparous species, the young develop inside eggs within the mother's body. The
nourishment is provided by the yolk of the egg.
The young hatch inside the mother's body and pass out through the anus.
(2) In viviparous species,
the young develop without egg inside of the mother's body. The young are nourished by secretions of the
female or through an umbilical-like cord.
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Recent news
Using fish as livestock feed threatens global fisheries
(11/18/2009)
Fish doesn't just feed humans. Millions of tons of fish are fed every year to chickens, pigs, and even farmed fish even in the midst of rising concerns over fish stocks collapses around the world. Finding an alternative to fish as livestock feed would go a long way toward preventing the collapse of fish populations worldwide according to a new paper in Oryx.
ICCAT fails to protect critically endangered tuna—again
(11/15/2009)
The International Commissions for the Conservation of Atlantic Tuna (ICCAT) ignored the advice of its scientists to end fishing of the Atlantic bluefin tuna. Instead ICAAT set a quota of 13,500 tons of fish. This is not the first time ICCAT has flouted its own researchers' advice: it has repeatedly set quotas well-above its researchers' recommendations.
Governments, public failing to save world's species
(11/04/2009)
According to the International Union for the Conservation of Nature's (IUCN) 2008 report, released yesterday, 36 percent of the total species evaluated by the organization are threatened with extinction. If one adds the species classified as Near Threatened, the percentage jumps to 44 percent—nearly half.
Atlantic bluefin tuna should be banned internationally: ICCAT scientists
(10/29/2009)
Scientists with the International Commission for the Conservation of Atlantic Tuna (ICCAT) have said in a new report that a global ban on Atlantic bluefin tuna fishing is justified. ICCAT meets in November to decide if they will follow their scientist's recommendations.
The Yangtze River may have lost another inhabitant: the Chinese paddlefish
(10/22/2009)
In December of 2006 it was announced that the Yangtze River dolphin, commonly known as the baiji, had succumbed to extinction. The dolphin had survived on earth for 20 million years, but the species couldn't survive the combined onslaught of pollution, habitat loss, boat traffic, entanglement in fishing hooks, death from illegal electric fishing, and the construction of several massive dams. Now, another flagship species of the Yangtze River appears to have vanished.
Freshwater species worse off than land or marine
(10/15/2009)
Scientists have announced that freshwater species are likely the most threatened on earth. Extinction rates for freshwater inhabitants are currently four to six times the rates for terrestrial and marine species. Yet, these figures have not lead to action on the ground.
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