Effect of Temperature on Maturation, Spawning and Pigmentation of Xiphophorus helleri (Swordtail)
Sabreena Bhat
Division of Aquaculture, Faculty of Fisheries, Rangil, Shere –e- Kashmir University of Agricultural Sciences and Technology, Srinagar, India.
Anayitullah Chesti
Division of Aquaculture, Faculty of Fisheries, Rangil, Shere –e- Kashmir University of Agricultural Sciences and Technology, Srinagar, India.
Mansoor Rather *
Division of Aquaculture, Faculty of Fisheries, Rangil, Shere –e- Kashmir University of Agricultural Sciences and Technology, Srinagar, India.
Shahied Khan
Division of Aquaculture, Faculty of Fisheries, Rangil, Shere –e- Kashmir University of Agricultural Sciences and Technology, Srinagar, India.
Ahsan Kamil Lone
Division of Aquatic Environmental Management, Faculty of Fisheries, Rangil, Shere –e- Kashmir University of Agricultural Sciences and Technology, Srinagar, India.
Imtiyaz Qayoom
Division of Aquatic Environmental Management, Faculty of Fisheries, Rangil, Shere –e- Kashmir University of Agricultural Sciences and Technology, Srinagar, India.
Sabina Darve
Division of Fisheries Resource Management, Faculty of Fisheries, Rangil, Shere –e- Kashmir University of Agricultural Sciences and Technology, Srinagar, India.
*Author to whom correspondence should be addressed.
Abstract
This study assessed the impact of varying water temperatures on spawning, maturation, and pigmentation in Xiphophorus helleri (swordtail) over a period of sixty days. Four temperature treatments were set up at 21°C (T0), 24°C (T1), 27°C (T2), and 30°C (T3), with ten fish per tank using a 25-litre aquarium. Continuous aeration and thermostatic control maintained stable conditions. The daily water exchange ensured cleanliness by removing leftover feed and excreta. Among the treatments, 27°C (T2) showed the best reproductive performance. This temperature yielded the highest Gonadosomatic Index (GSI) for females (9.60±0.009) and males (7.83±0.008), as well as Hepatosomatic Index (HSI) values (1.47±0.008 for females). T2 also had the best spawning rate (21.85±2.10) and fry production (30.00±0.816), along with the most advanced oocyte maturation stages (vitellogenic oocytes). In terms of skin pigmentation, carotenoid levels were also highest at 27°C (2.92±0.170), with the best survival rate observed at 95.00% for this treatment, though survival differences across treatments were statistically non-significant (p>0.05). The current study affirmed that temperature is a pivotal factor in regulating spawning, maturation, and the enhancement of pigmentation in swordtails.
Keywords: Xiphophorus helleri, spawning rate, maturity stages, pigmentation, carotenoid content