Population dynamics and biology of an invasive population of mosquitofish Gambusia affinis in a temperate estuarine lake system
Hans Sloterdijk
Nicola C James
M Kyle S Smith
Werner Ekau
Olaf LF Weyl
Abstract
This study investigates the distribution, relative abundance, population growth and biology of the alien invasive fish Gambusia affinis in the Wilderness Lakes System, a coastal lake system in the warm-temperate region of South Africa. Fish were collected throughout the system during four seasonal sampling trips in spring (October 2010), summer (February 2011), autumn (May 2011) and winter (July 2011). Gambusia affinis were widespread and abundant in all habitats from the freshwater reaches of the inflowing Touw River to the more saline lakes and estuary. Sex ratio was generally female dominated and mean length at maturity was 14.7 mm standard length (SL) for males and 20.3 mm SL for females. Reproduction was strongly seasonal with reproductively active fish sampled in spring and summer but not in autumn and winter. Relative abundance also varied seasonally, with populations following typical ‘boom and bust’ population dynamics. By winter, the population in all habitats was lower with mortality rates as high as 85%. The stronghold of the population appears to be in the channels between the lakes, where relative abundance was more consistent and winter mortality rates were lower. The survivors, which are primarily females, then reconstitute the population in the spring and summer months.
Sloterdijk H., James N.C., Smith M.K.S., Ekau W. and Weyl O.L. (2015) Population dynamics and biology of an invasive population of mosquitofish Gambusia affinis in a temperate estuarine lake system. African Zoology 50(1): 31-40. 10.1080/15627020.2015.1021169
@article{Sloterdijk2015,
Title = {Population dynamics and biology of an invasive population of mosquitofish Gambusia affinis in a temperate estuarine lake system},
Author = {Sloterdijk, Hans and James, Nicola C and Smith, M Kyle S and Ekau, Werner and Weyl, Olaf LF},
Editor = {},
Journal = {African Zoology},
Year = {2015},
Pages = {31-40},
Volume = {50},
Doi = {10.1080/15627020.2015.1021169},
Abstract = {This study investigates the distribution, relative abundance, population growth and biology of the alien invasive fish Gambusia affinis in the Wilderness Lakes System, a coastal lake system in the warm-temperate region of South Africa. Fish were collected throughout the system during four seasonal sampling trips in spring (October 2010), summer (February 2011), autumn (May 2011) and winter (July 2011). Gambusia affinis were widespread and abundant in all habitats from the freshwater reaches of the inflowing Touw River to the more saline lakes and estuary. Sex ratio was generally female dominated and mean length at maturity was 14.7 mm standard length (SL) for males and 20.3 mm SL for females. Reproduction was strongly seasonal with reproductively active fish sampled in spring and summer but not in autumn and winter. Relative abundance also varied seasonally, with populations following typical ‘boom and bust’ population dynamics. By winter, the population in all habitats was lower with mortality rates as high as 85%. The stronghold of the population appears to be in the channels between the lakes, where relative abundance was more consistent and winter mortality rates were lower. The survivors, which are primarily females, then reconstitute the population in the spring and summer months.},
}
TY - JOUR
AU - Sloterdijk, Hans
AU - James, Nicola C
AU - Smith, M Kyle S
AU - Ekau, Werner
AU - Weyl, Olaf LF
TI - Population dynamics and biology of an invasive population of mosquitofish Gambusia affinis in a temperate estuarine lake system
T2 - African Zoology
PY - 2015
SP - 31-40
VL - 50
DO - 10.1080/15627020.2015.1021169
AB - This study investigates the distribution, relative abundance, population growth and biology of the alien invasive fish Gambusia affinis in the Wilderness Lakes System, a coastal lake system in the warm-temperate region of South Africa. Fish were collected throughout the system during four seasonal sampling trips in spring (October 2010), summer (February 2011), autumn (May 2011) and winter (July 2011). Gambusia affinis were widespread and abundant in all habitats from the freshwater reaches of the inflowing Touw River to the more saline lakes and estuary. Sex ratio was generally female dominated and mean length at maturity was 14.7 mm standard length (SL) for males and 20.3 mm SL for females. Reproduction was strongly seasonal with reproductively active fish sampled in spring and summer but not in autumn and winter. Relative abundance also varied seasonally, with populations following typical ‘boom and bust’ population dynamics. By winter, the population in all habitats was lower with mortality rates as high as 85%. The stronghold of the population appears to be in the channels between the lakes, where relative abundance was more consistent and winter mortality rates were lower. The survivors, which are primarily females, then reconstitute the population in the spring and summer months.
ER -
