Spatiotemporal occurrence and feeding habits of tonguefish,Cynoglossus lightiNorman, 1925, larvae in Ariake Bay, Japan

Abstract

Summary Spatiotemporal occurrence and feeding habits of tonguefish (Cynoglossus lighti Norman, 1925) larvae were investigated in an offshore area (>5 m in depth) of the inner part of Ariake Bay, Japan. All specimens were symmetric, free‐swimming larvae. Although their seasonal abundance and distribution in the study site varied from year to year, spawning started in June and the larval abundance was high in August and September with a wide distribution in the inner part of the bay. Both present and previous study results strongly suggest that larvae may settle primarily in the estuary and near‐shore areas of Ariake Bay after their wide distribution in the offshore area of the bay during the free‐swimming stage. Larvae showed a clear feeding rhythm in which they fed on prey mainly during the daytime. Larvae fed exclusively on copepods, and identified prey were mostly Paracalanidae (mainly Parvocalanus crassirostris), Microsetella norvegica, and Oithona davisae. Pre‐metamorphosis larvae fed primarily on Paracalanidae and O. davisae, whereas O. davisae formed a smaller proportion of the early‐metamorphosis diet. In early metamorphoses, larvae fed preferentially on Paracalanidae and M. norvegica.

Does structural change in the zooplankton community affect larval fish feeding in anthropogenically disturbed tropical waters?

“…Copepod nauplii and eggs were mainly eaten by the preflexion stages of these families, and it is noted that the ingested copepod eggs could also be contributed by the detached eggs of egg-bearing copepods. Our findings are consistent with the study by Kume et al (2015) in Japanese waters for the diet of Cynoglossus lighti which prey mainly on paracalanid (P. crassirostris), harpacticoid (M. norvegica) and oithonid (Oithona davisae) copepods. Sampey et al (2007) reported a similar dietary composition of harpacticoids, cyclopoids and calanoids for the postflexion stages of the Cynoglossidae and Callionymidae in Australian waters.…”

Re-evaluation of the taxonomic status of four nominal, western Pacific species of tongue soles (Pleuronectoidei: Cynoglossidae: Cynoglossus), with redescription of C. joyneri Günther, 1878

“…Consequently, reliability of conclusions of these earlier studies is difficult to assess. Although several previous investigations concluded that C. lighti is a synonym of C. joyneri (Matsubara 1955;Menon 1977;Wang et al 2018), C. lighti still appears in contemporary literature (Koshiishi et al 2001;Yamaguchi & Kume 2004;Yagi et al 2009;Kume et al 2012;Ping & Liu 2014;Kume et al 2015;Song et al 2015;Wang et al 2018;Sun et al 2021) indicating that taxonomic status of these nominal species remains unresolved.…”