Spawning ground selection and larval feeding habits of Arabesque greenling Pleurogrammus azonus around the Matsumae Peninsula, Japan

We investigated the geographical distribution and feeding habits of Arabesque greenling Pleurogrammus azonus larvae along the Tatehama coast of Hokkaido Japan and its eastern waters from November to February. The goal was to gain insights into choice of spawning grounds and early life history. Yolk-sac larvae were predominantly found in the surface water layer near the Tatehama coast during late January to late February, and they were transported to the offshore regions by the Tsushima-Tsugaru Warm Current. During the early developmental stages, the yolk-sac larvae primarily fed on Oithona similis copepodites, which are larger than the copepod nauplii consumed by other marine fish species. Our observations of high feeding activity in the surface layer in offshore deep-water areas led us to hypothesize that the Tatehama coast may serve as a spawning ground for adult P. azonus due to its proximity to offshore areas, allowing larvae to quickly reach suitable feeding grounds after hatching. The larger egg diameter, longer body length, larger eyes with guanine pigmentation, coiled digestive system, and heavy body pigmentation of P. azonus suggest their ability to prey on copepodites and maintain sustained feeding intensity.