Inprovidingshelterforsea-cucumbers,artificialreefsalsoprotectandenhancesea-cucumberstocks.However,fewstudieshavebeenconductedonthebenefitsandattractiveeffectsofartificialreefsontheJapanesesea-cucumber,undernaturallightinanexperimentalwater-tank,withandwithout(controlgroup)artificialreefmodels,wasobserved.of2–7cmbodylengthand2–30gbodyweightwereused.Thefloorofthewatertankwasdividedinto15sectionswithdifferentartificialreefmodelsvaryinginshape,materialanddistancefromthetankbottom(referredtoas“space”).Meandistributionrates(MDR)ofwererecordedandthemeanattractiverates(MAR)ofthereefmodelswereanalyzedandcompared.Observationsdemonstratedthattendedtoclimbthetankwallinsearchofshadedareasornarrowinterspaces.ForthePVCreefmodels,passedthroughthembutseldomstayed.TheMARforthetriangularprismmodelwithoutabaseandspacewassignificantlydifferentfromthecontrolgroup(<0.01),thetriangularprismmodelwithabaseandspaceandthetriangularprismmodelwithabaseandwithoutspace(<0.05).TheMARoftheclaymodelwassignificanthigherthaneitherthecementorPVCmodels(<0.05).TheMARofthetilemodelwitha3.4-cmspacefromthetankbottomwasverysignificantlydifferentfromthecontrolgroup((2)thepreferenceforreefshapewasrelatedtointerspacesanddegreeofshade,and(3)thepreferenceforreefmaterialwasrelatedtosurfaceroughness,whichwastoppriorityfor