Seasonal Impacts of Physical and Chemical Factors on Aquatic Fungi and Common Carp

Abstract

Saprolegniosis is recognized as one of the most widespread fungal diseases in freshwater fish, affecting fish and eggs of all ages and causing significant economic losses globally. The primary infectious agents are aquatic mold fungi belonging to the Saprolegnia spp. This study aimed to investigate the impact of physical and chemical factors on aquatic fungi and their relationship with common carp. This study was conducted over 12 months from July 1; 2021, to 1 July 2022, at Khurmal Pond, located in Sulaimani Governorate. Eight sites were selected, and a baiting method was used to isolate the aquatic fungus from water samples. The water temperature ranged between (11.3-26.6 centigrade °C), the pH ranges from 7.2 to 7.8 indicating a neutral to slightly essential, dissolved oxygen (DO) levels varied between 6 to 8.4 mg/L at the months of the experiment, total alkalinity (218-272 mg/L), the concentration of nutrient like as NO3 (5.33-9.26 mg/L), SO4 (30.3-35.3 mg/L) and PO4 (0.15-0.64 mg/L). Twenty-five species of fungi were isolated in this detection: 17 species of Zoosporic fungi and eight species of conidial fungi representing eleven genera, namely: Zoosporic Fungi belonging to 5 genera Achly, Aphanomyces, Dictyuchus, Pythium, and Saprolegnia, Conidial fungi were belonging to 6 genera Alternarea, Aspergillus, Curvulari, Fusarium, Pencillum and Rhizopous. In conclusion, Saprolegniosis threatens freshwater aquaculture globally and explores how physical and chemical factors affect the occurrence and frequency of aquatic fungus in common carp disease.