Description of the life cycle of Dolops discoidalis (Branchiura: Argulidae), collected in Pseudoplatystoma punticfer raised in captivity in the Peruvian Amazon

Abstract

Species of Branchiura have structures that undergo evolutionary modifications such as: oral suction apparatus and hook-shaped appendages, which are used for attachment to the host causing lesions on the skin (that can lead to secondary bacterial infections) and anaemia that can cause high mortality rates. The present study aimed to describe the life cycle of the branchiuran Dolops discoidalis (Bouvier, 1899) in order to contribute to the knowledge of the biology of this parasite and for future studies focused on its prevention and control in fish farming. Samples were collected in July 2021 from a fish pond located in Iquitos, Peru. Branchiurans were observed parasitizing the dorsal and ventral part of the body of Pseudoplatystoma punctifer (Castelnau, 1855). Parasites were collected using tweezers and placed in a container with water for later transfer to the laboratory. In the laboratory, collected branchiurans were placed in glass aquariums lined with plastic, waiting for mate and/or oviposition. Once oviposition was observed, eggs were transferred to 500 mL capacity beakers with constant aeration provided by a small diffuser stone connected to a hose. Eggs were observed once a day and changes in their morphology were photographed and registered. The observation of the eggs was carried out until the hatching of the juvenile. The life cycle of D. discoidalis from egg laying to juvenile hatching lasted 23 days. Since P. punctifer is being bred in captivity in the Peruvian Amazon, it is necessary to know aspects related to sanity, emphasizing the problems caused by parasites. The knowledge of the life cycle of D. discoidalis helps us to adopt measures to prevent and control the parasitism of this species and thus contribute to aquaculture activities in the Peruvian Amazon. © 2022 Elsevier B.V.