Ontogenetic changes in the body structure of the Arctic fish Leptoclinus maculatus

Histological studies of the ontogenetic changes in Arctic marine fishes are often fragmented and incomplete. Here we present a comprehensive histological ontogenetic analysis of the daubed shanny (Leptoclinus maculatus) from the Arctic, characterizing its development as it undergoes a series of changes in the organ and tissue organization, especially during the postlarvae transition from the pelagic to benthic lifestyle. The thyroid, heart, digestive tract, liver, gonads, blood, and the lipid sac of the postlarvae at different developmental stages (L1-L5) were studied for the first time. We found that L. maculatus has structural characteristics of marine fish developing in cold, high-oxygen polar waters. We conclude that the presence of the lipid sac and the absence of distinguishable red blood cells in pelagic postlarvae are unique features of the daubed shanny most likely linked to its successful growth and development in the Arctic environment.

Automated summary

This study presents a comprehensive histological ontogenetic analysis of the daubed shanny from the Arctic, focusing on the postlarvae transition from pelagic to benthic lifestyle. The research examined various organs and tissues, including the thyroid, heart, digestive tract, liver, gonads, blood, and lipid sac, in different developmental stages. The study found that the daubed shanny exhibits structural characteristics of marine fish in cold, high-oxygen polar waters, and suggests that the presence of a lipid sac and the absence of distinguishable red blood cells in pelagic postlarvae are unique adaptations for successful growth and development in the Arctic environment.