New Record and Biology of the Molly Poecilia sphenops (Poeciliidae), Discovered in the Northern Sahara of Algeria

Abstract

This study reports data on the first observation and biology of the Molly Poecilia sphenops, an exotic fish species recently introduced into two natural and artificial aquatic hydrosystems of Northern Sahara (Algeria). A total of 56 individuals were captured during September 2017 in Lake Megarine and tested for morphometric. Females of P. sphenops are larger than males (mean TLFₑₘₐₗₑ = 56 ± 6.33 mm, mean TLMₐₗₑ = 46 ± 8 mm). The allometric type determination reveals isometric growth of the different morphometric characters considered as a function of total length in both sexes. Females weight more than males. The lenghth-weight relationship in both sexes follows an isometric evolution (bfₑₘₐₗₑ = 3.04, bₘₐₗₑ = 3.44). The sex ratio is in favour of females (1.0 : 1.2), it varies significantly according to the size classes (χ² = 10.68, p = 0.03). The gonado-somatic index is larger in females (18.3 ± 9.8) than in males (3 ± 1.8). Mean absolute fecundity is 93.5 ± 63.83 eggs and varies independently of the length and total weight of P. sphenops. KEYWORDS: exotic fish, introduction, growth, reproduction, Northern Sahara, Algeria