Jack mackerel Trachurus japonicus juveniles use jellyfish for predator avoidance and as a prey collector
- 156 Downloads
Juveniles of carangid fishes including jack mackerel Trachurus japonicus are known to associate with jellyfishes. The function of this association behavior was studied through rearing experiments and underwater visual observations. Association behavior of jack mackerel with moon jellyfish in experimental tanks was more frequent in the presence compared to the absence of predators (chub mackerel Scomber japonicus). In the experimental tanks, the presence of jellyfish, however, did not mitigate predation by these predators. Although jack mackerel did not feed on the jellyfish itself, they frequently fed on the captured prey (Artemia nauplii) whilst in the gut cavity of the jellyfish. Underwater observations of giant jellyfish Nemopilema nomurai off Kyoto and Fukui prefectures revealed that approximately 30% of these jellyfish were accompanied by jack mackerel juveniles with body sizes ranging 10–45 mm standard length (SL). Considering that jack mackerel juveniles found in subtidal rocky reefs ranged 40–120 mm SL, we considered that jack mackerel from 10 to 45 mm SL associate with jellyfish as a hiding place as well as a food collector, until they find a suitable reef habitat when they attain approximately 40 mm SL.
Key WordsAurelia aurita behavioral ontogeny Carangidae commensal behavior Nemopilema nomurai predation survival Trachurus japonicus
Unable to display preview. Download preview PDF.
- 2.Kingsford MJ. Biotic and abiotic structure in the pelagic environment: importance to small fishes. Bull. Mar. Sci. 1993; 53: 393–415.Google Scholar
- 6.Mitani T, Uehara S, Ishida M, Saito T. Abundance fluctuation and recruitment of Japanese jack mackerel, Trachurus japonicus, in the Pacific off southern Japan. Fish. Oceanogr. Kuroshio. 2001; 2: 45–54 (in Japanese).Google Scholar
- 10.Uye S, Fujii N, Takeoka H. Unusual aggregations of the scyphomedusa Aurelia aurita in coastal waters along western Shikoku, Japan. Plankton Biol. Ecol. 2003; 50: 17–21.Google Scholar
- 16.Masuda R. Seasonal and interannual variations of subtidal fish assemblages in Waskasa Bay with reference to the warming trend in the Sea of Japan. Envir. Biol. Fish. (in press) http://www.springerlink.com/content/cx303857725v0026/?p-aed0294bf583457ca52d9f8da0eff751&pi=23Google Scholar
- 19.Shojima Y. On the postlarvae and juveniles of carangid fishes collected together with the jelly-fishes. Cont. Seikai Reg. Fish. Res. Lab. 1962; 147: 48–58.Google Scholar
- 23.Masuda R, Tsukamoto K. Onset of association behavior in striped jack, Pseudocaranx dentex, in relation to floating objects. Fish. Bull. 2000; 98: 864–869.Google Scholar