Swordtails, Guppies, Platies, One Spot Livebearers and Sailfin Mollies all belong to a group of fish known as livebearers (Family Poeciliidae).
Livebearers, or ovoviviparous fish, have internal fertilisation in which embryos develop fully within the female, culminating in birth of live larvae.
These exotic species are known to dominate fish communities in many streams in the Brisbane region, often resulting in either a reduction in native fish numbers or the total elimination of native fish species. Many of these streams have a high level of habitat disturbance.
Swordtails (Xiphophorus helleri) and platies (X. maculatus) are popular non-indigenious a
quarium species.
Swordtails in particular are now widely distributed in Brisbane and further north in coastal streams. Swordtails appear to compete for space rather than food.
The platies (X. maculatus) and sailfin molly (Poecilia latipinna) have a patchy distribution throughout Australia.
In general, the introduction of a livebearer (Poeciliid species) has been shown to have detrimental effects on small surface-dwelling native fish populations.
When two or more species of livebearers are present, all surface-feeding native fish species become rare or disappear.
For example, gambusia and swordtails found together and in large numbers depress endemic fish populations.
Where guppies (Poecilia reticulata) and gambusia are abundant in Brisbane streams, native fish are rare. |
