Experimental evidence indicates that native freshwater fish outperform introduced Gambusia in mosquito suppression when water temperature is below 25°C

Craig Lawrence,Dean Meredith,Neil Rutherford,Rod Hamilton

doi:10.1007/s10750-015-2470-3

Craig Lawrence, Dean Meredith + Show 2 more

Open Access

https://doi.org/10.1007/s10750-015-2470-3

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Abstract

In a series of laboratory trials, we compared the mosquito larvae predation efficacy of four endemic fish species and the introduced Gambusia holbrooki at different temperatures. Galaxias occidentalis and Galaxias truttaceus, consumed more mosquito larvae at 15 and 20°C and were equally effective consumers of mosquito larvae as G. holbrooki at 25°C. Nannoperca vittata and Bostokia porosa were equally as effective at consuming mosquito larvae as G. holbrooki at 15, 20 and 25°C. G. occidentalis in particular warrant further investigation as a mosquito control agent, not only due to their high consumption of mosquito larvae, but also due to their propensity to kill, but not consume more mosquito larvae than the other four fish species at both 15 and 20°C. For this species, stomach size and digestion rate do not appear to limit the number of mosquito larvae killed. These results indicate that endemic fish species may be more successful than the introduced G. holbrooki at mosquito control.

Highlights

Despite a lack of research quantifying their effectiveness as a biological control agent for mosquitoes, in the early 1900s international health authorities and philanthropic organisations introduced Eastern Gambusia (Gambusia holbrooki Girard, 1859 Poeciliidae) or Western Gambusia (Gambusia affinis Baird & Girard, 1853 Poeciliidae) to all continents except Antarctica (Courtenay & Meffe, 1989; Lloyd, 1990)
In 1934, without any prior evaluation of endemic fish species, G. holbrooki was introduced to Western Australia and distributed by the Public Health Department to prevent the spread of mosquito-borne disease (Mees, 1977)
The temperate endemic galaxiids (G. occidentalis and G. truttaceus) consumed more mosquito larvae at both 15°C (P = 0.04) and 20°C (P = 0.01) than G. holbrooki. Both endemic galaxiids were effective consumers of mosquito larvae compared to G. holbrooki at tropical temperatures 25°C (P = 0.49) (Table 1)

Summary

Introduction

Despite a lack of research quantifying their effectiveness as a biological control agent for mosquitoes, in the early 1900s international health authorities and philanthropic organisations introduced Eastern Gambusia (Gambusia holbrooki Girard, 1859 Poeciliidae) or Western Gambusia (Gambusia affinis Baird & Girard, 1853 Poeciliidae) to all continents except Antarctica (Courtenay & Meffe, 1989; Lloyd, 1990). G. holbrooki has a colonizing life history (i.e. early maturation, high reproductive effort) that enables them to rapidly populate a waterbody (Macdonald & Tonkin, 2008) This combined with their agonistic behaviour has contributed to the loss of endemic fish species (Myers, 1965; Coy, 1979; Gill et al, 1999) and has led to them being the most abundant freshwater fish species on the Swan Coastal Plain, where they represent 79% of the total fish abundance in this region (Hourston et al, 2014). Despite the wide distribution and abundance of Gambusia, in south-western Australia the incidence of mosquito-borne diseases such as Ross River virus, Barmah Forest virus, Murray Valley encephalitis virus and Kunjin virus has not decreased (Russell, 1998, 2002)

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