Effect of Lethal and Sub-lethal Concentrations of Heavy Metal (Zinc) on Opercular Beat Frequency (OBF) in Cyprinus carpio var. communis
Nafath ul Arab *
Division of Aquatic Environmental Management, Faculty of Fisheries, SKUAST-K, Ganderbal –190006, J&K, India.
Adnan Abubakr
Division of Aquatic Environmental Management, Faculty of Fisheries, SKUAST-K, Ganderbal –190006, J&K, India.
Farooz Ahmad Bhat
Division of Fisheries Resource Management, Faculty of Fisheries, SKUAST-K, Ganderbal –190006, J&K, India.
Feroz Ahmad Shah
Division of Aquatic Animal Health Management, Faculty of Fisheries, SKUAST-K, Ganderbal –190006, J&K, India.
Monisa Malik
Division of Aquatic Environmental Management, Faculty of Fisheries, SKUAST-K, Ganderbal –190006, J&K, India.
Bilal Ahmad Bhat
Division of Agri- economics, Faculty of Agriculture, SKUAST-K, Wadoora–193201, J&K, India.
Imtiyaz Qayoom
Division of Aquatic Environmental Management, Faculty of Fisheries, SKUAST-K, Ganderbal –190006, J&K, India.
Asim Iqbal Bazaz
Division of Fisheries Resource Management, Faculty of Fisheries, SKUAST-K, Ganderbal –190006, J&K, India.
Snowber Mir
Division of Aquatic Environmental Management, Faculty of Fisheries, SKUAST-K, Ganderbal –190006, J&K, India.
*Author to whom correspondence should be addressed.
Abstract
In the present investigation, the acute and sublethal toxicity of a grey list heavy metal (Zinc) on the juvenile of Common carp (Cyprinus carpio) was evaluated to determine its effect on the Opercular beat frequency (OBF) under laboratory conditions. The fish was exposed to varying levels of the toxicant (2.12mg/L; 4.25mg/L and 8.50 mg/L) for 96 hrs using static bioassay. Opercular beat frequency (OBF) in exposed fishes initially increased at 6 hr and 12 hr time interval compared to the control followed by a gradual decrease at later time points (48, 72 and 96 hour time intervals) that reflected a mild inhibitory effect. The operculum beat frequency was significantly (P< 0.05) affected by the exposure and concentration indicating an impaired respiratory function. A decline or alteration in OBF suggests respiratory stress, which is a direct marker of toxic effects. This study gives clear insight into how zinc toxicity impair basic life-sustaining functions in fishes. These findings highlight the potential of opercular beat frequency as a sensitive bioindicator for assessing sublethal respiratory stress in fish exposed to heavy metal contaminants like zinc.
Keywords: Zinc, heavy metal, opercular beat frequency, carp, toxicity, lethal exposure