▁authority . ▁Its ▁range ▁extends ▁from ▁Norway ▁to ▁the ▁Mediter rane an ▁Sea ▁and ▁the ▁Az ores . ▁It ▁occurs ▁on ▁the ▁se ab ed ▁on ▁soft ▁substr ates ▁including ▁co arse ▁sand , ▁fine ▁sand , ▁gra vel ▁and ▁mud dy ▁sand . ▁It ▁is ▁common ▁round ▁the ▁coast s ▁of ▁the ▁British ▁Is les ▁and ▁has ▁occurred ▁at ▁dens ities ▁as ▁great ▁as ▁ 9 0 0 ▁per ▁. ▁ ▁Bi ology ▁O phi ura ▁alb ida ▁is ▁a ▁pred ator ▁and ▁sc aven ger ▁and ▁fe eds ▁on ▁such ▁small ▁in verte br ates ▁as ▁pol ych a ete ▁w orm s , ▁cr ust ace ans ▁and ▁b ival ve ▁m oll us cs . ▁In ▁the ▁Balt ic ▁Sea ▁it ▁is ▁the ▁favour ite ▁food ▁of ▁the ▁star fish ▁Lu idia ▁s arsi ▁and ▁is ▁chosen ▁in ▁preference ▁to ▁other ▁brit t le ▁stars . ▁In ▁the ▁Irish ▁Sea ▁it ▁is ▁e aten ▁along ▁with ▁the ▁common ▁brit t le ▁star ▁( O phi oth rix ▁frag ilis ) ▁by ▁the ▁fast - mov ing ▁seven ▁armed ▁star fish ▁( L uid ia ▁c ili aris ). ▁ ▁Ind ividual s ▁of ▁this ▁species ▁are ▁either ▁male ▁or ▁female . ▁F ert il isation ▁is ▁external ▁and ▁the ▁lar va e ▁are ▁pl ank ton ic . ▁It ▁is ▁a ▁fast - g row ing ▁brit t le ▁star ▁and ▁is ▁not ▁thought ▁to ▁live ▁for ▁more ▁than ▁three ▁years . ▁ ▁References ▁ ▁Category : O phi