Preliminary trials on the use of large outdoor tanks for the ongrowing of Octopus maya juveniles

Abstract

AbstractOctopus mayahas high growth rates, direct embryo-nicdevelopmentandhighhatchlingsurvival,makingit a good candidate for aquaculture diversi¢cation.The present study was designed to evaluate growthrate,survivalandfoodconversionofO.mayajuvenilescultured in outdoor tanks. Octopuses were capturedfrom the wild during the ¢shing season, and fed dis-carded ¢sh heads and whole crabs.Three trials wereconducted between 23 and 32 days, in September(trial1),October(trial2)andNovember(trial3)wherea decrease in sea water temperature was registered(29^24 1C,fromSeptembertoNovemberrespectively).Octopuseswereheldinthreeoutdoortanksof5m 2 ofbottom area and 0.5m deep, aerated sea water andwater £ow allowing10% of water exchange per day.Initial density was between 2.9 and 3.8kgm 3 withdiierent initial mean weight of 542.3 18.8,493 11.9 and 321 7.8g, for trials 1, 2 and 3 re-spectively. Speci¢c growth rate varied between 1.8and 2.7%BWday 1 with no apparent relation withthe culture temperature. These results put in evi-dencethattanksusedareadequatefortheongrowingof O. maya juveniles, with commercial size being at-tainedinafewweeks.Keywords: cephalopods,culture,growthrate,foodconversion,Octopusmaya,outdoortanksIntroductionThestudyofOctopusspp.culturehasrecentlyunder-gone a signi¢cant increase throughout the world,particularly in Spain, Italy, Portugal and Greece(Vaz-pires, Seixas & Barbosa 2004; Iglesias, Sanchez,Bersano, Carrasco, Dhont, Fuentes, Linares, Mun oz,Okumura, Roo,Van Der Meeren,Vidal & Villanueva2007). The need for diversi¢cation, taking into con-sideration biological and economical aspects, makescephalopods in general and octopuses in particular,potentialcandidates for industrialculture.TheYucatanoctopus,OctopusMaya,isanendemicspeciesfromtheYucatanpeninsula,withdistributionranging from the Campeche bay, in the North of theYucatanpeninsula,toIslaMujeres(Solis1967).Lately,the range has beenwidened inthe Northern limit toCiudaddelCarmen,Campeche(Solis1997,1998).Thisspecies accepts dead prey or prepared diets immedi-atelyafterbeingborn,andeasilyadaptstolaboratoryconditions (Rosas,Tut, Baeza, SaŁnchez, Sosa, Pasc-ual,Arena,DominguesC Derusha, Forsythe, Dimarco & Hanlon1989; Solis1998; Domingues, Lo¤pez, Mun oz, Maldo-nado, Gaxiola & Rosas 2007; Rosas, Cuzon, Pascual,Gaxiola, Lo¤pez, Maldonado & Domingues 2007; Ro-sas,Tut, Baeza, SaŁnchez, Sosa, Pascual, Arena, Dom-ingues&Cuzon2008)upto four(Hanlon&Forsythe1985) or ¢ve (Van Heukelem1983) generations. Thisspecies has fast growth rates up to 8%BWday