Feeding habits of ocellate spot skate, Okamejei kenojei (Müller & Henle, 1841), in coastal waters of Taean, Korea

Abstract

The feeding habits of Okamejei kenojei were studied using 592 specimens collected in the coastal waters of Taean, Korea from April 2008 to March 2009. O. kenojei is a bottom-feeding carnivore that consumes mainly shrimp, fishes, and crabs. Its diet also includes small quantities of amphipods, mysids, cephalopods, euphausiids, copepods, isopods, and polychaetes. The total length (TL) of individuals in this study ranged from 8.2 to 49.0 cm. Cluster analysis based on %IRI (index of relative importance) identified three size classes. Group A (< 20 cm TL) ate primarily caridean shrimp and amphipods; group B (20-30 cm TL) ate exclusively shrimp; and group C (> 30 cm TL) ate penaeoidean shrimp, fishes, and crabs. O. kenojei showed ontogenetic changes in feeding habits. Although shrimps were the primary food consumed by all size groups, the proportion of shrimp in the total diet decreased and the consumption of fishes and crabs gradually increased with the body size of O. kenojei. Size of the prey organisms also increased. Smaller individuals fed mainly on small prey, such as amphipods, mysids, and small shrimp, whereas larger individuals preferred larger prey, such as larger shrimp, fishes, and crabs. The size-related diet breadth and the percentage of empty stomachs were significant; the diet breadth gradually increased with body size, whereas the percentage of empty stomachs decreased. Seasonal changes in the O. kenojei diet were not significant, but shrimp constituted 97.3% of the summer diet by %IRI. Seasonal changes in diet breadth and the percentage of empty stomachs were not significant.

Population structure of the ocellate spot skate (Okamejei kenojei) inferred from variations in mitochondrial DNA (mtDNA) sequences and from morphological characters of regional populations

“…Okamejei kenojei has considerable economic value in Korea and Japan (Ishihara, 1990;Ishihara et al, 2009;Baeck et al, 2011). Domingues et al (2018) suggested that management and conservation policies for shark and ray fisheries should include information on genetic diversity.…”

Trophic ecology of two syntopic sciaenid species (Micropogonias furnieri(Desmarest, 1823) andCtenosciaena gracilicirrhus) (Metzelaar, 1919) in a tropical bay in south-eastern Brazil

“…According to Gerking (), the diets of syntopic species in different genera are not expected to overlap, plus the availability of feeding resources influences the number of individuals and species that can coexist in a given habitat (Piet, Pfisterer, & Rijnsdorp, ; Schuckel, Sell, Kroncke, & Reiss, ). Spatial, temporal and/or ontogenetic segregation among the feeding resources are common strategies developed by species to avoid intra and interspecific competition (Baeck, Park, Choi, Hug, & Park, ; Lomiri, Scacco, Mostarda, & Andaloro, ; Young et al., ).…”

Age, growth, and age at sexual maturity of the commercially landed skate species,Dipturus chinensis(Basilewsky, 1855), in the northern East China Sea

“…The East China Sea, located across both temperate and subtropical zones and bound by China, South Korea and Japan, is near the southern border of the distribution range of D. chinensis. Skates are caught by Japanese and Korean trawlers, and are commercially important fish in the East China Sea and adjacent waters (Baeck, Park, Choi, Huh, & Park, 2011;Hara, Furumitsu, & Yamaguchi, 2014;Ishihara, 1990).…”

“…Skates are caught by Japanese and Korean trawlers, and are commercially important fish in the East China Sea and adjacent waters (Baeck, Park, Choi, Huh, & Park, 2011;Hara, Furumitsu, & Yamaguchi, 2014;Ishihara, 1990).…”