Reproductive ecology of Garra ghorensis, a critically endangered fish in Jordan
2015
Hamidan, Nashat | Britton, J Robert
The life history traits of desert fishes indicate their resilience to environmental change and vulnerability to extirpation and extinction. Garra ghorensis is a small (<140 mm) riverine cyprinid fish endemic to the Southern Dead Sea area and is critically endangered through habitat loss and invasive species. Here, the reproductive ecology of three Jordanian populations of this species were assessed through the collection of monthly samples between February 2011 and January 2012 in a region where air temperatures ranged between below 0 °C and over 40 °C through the year. Samples contained fish up to 137 mm fork length, with most <100 mm. Fish matured at length below 40 mm and at ages <1 year. Except one population of female dominated, sex ratios were not significantly different from 1:1. Reproductive effort, as gonado-somatic index (I G), peaked in both sexes in May, indicating spawning commenced soon after, with gonad maturation occurring at mean air temperatures below 20 °C and spawning above 20 °C. Mean female I G by month suggested protracted spawning throughout the summer months. Both mean I G and fecundity varied between sites, with the highest values at the most disturbed site. In combination, these outputs suggest G. ghorensis has an opportunistic life history strategy with sufficiently plastic reproductive traits that enable adaptation to shifting conditions. These are likely to provide resilience to habitat alterations and suggest that the plasticity of their reproductive traits might be important in developing strategies to safeguard their populations in the face of continued habitat degradation.
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