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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
Mangroves are key to healthy fisheries, finds study
(7/21/2008) Mangroves serve as a critical nursery for young marine life and therefore play an important role in the health of fisheries and the economic well-being of fishermen, report researchers writing in the early online edition of the Proceedings of the National Academy of Sciences.
Marine no-take zones are succeeding beyond expectations
(7/16/2008) Two recent reports show that marine no-take zones, where fishing is completely prohibited, are helping to rejuvenate commercial species faster than expected.
The global rich are eating the poor's fish: new report shows tropical fish catch gravely under-estimated
(7/10/2008) After a week of bad news regarding marine life — it was reported that half of U.S. coral reefs are in fair to poor condition and one-third of all coral species are threatened globally — there is still more: a study of twenty tropical islands showed that recreational and subsistence fishing has gone almost completely unreported from 1950 to 2004. In fifteen of twenty cases the fish take was at least doubled when local fish catches were added, and in the most extreme case, American Samoa, the amount of fish collected was 17 times what was previously recorded.
Census of marine life opens with 122,000 species
(7/1/2008) Discovering a new species can be the highlight of a biologist's career. Yet once a species enters the formal literature, complications may develop. The systen has been especially problematic because for centuries biologists have lacked the tools to construct a full and flexible list of the world's innumerable species. Using the Internet and hundreds of scientists around the world, the Census of Marine Life is attempting to take on this monumental task.
Large shark populations fall 97% in the Mediterranean
(6/12/2008) Populations of some shark species in the Mediterranean have plunged by more than 97 percent over the past 200 years, report researchers writing in the journal conservation Biology. Several species are at risk of extinction.
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