TY - JOUR AU - Katsanevakis, Stelios AU - Verriopoulos, George PY - 2004/03/30 Y2 - 2024/03/29 TI - Den ecology of Octopus vulgaris Cuvier, 1797, on soft sediment: availability and types of shelter JF - Scientia Marina JA - Sci. mar. VL - 68 IS - 1 SE - Articles DO - 10.3989/scimar.2004.68n1147 UR - https://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/352 SP - 147-157 AB - To avoid predation, octopuses select and actively modify shelters (also called dens) in the substratum, where they remain most of the time, especially during daylight hours. The main questions that this study deals with are: Is den availability a significant constraint for the distribution of <i>Octopus vulgaris</i> on soft sediment? What kind of dens does O. vulgaris use on soft sediment and what factors affect the selection of one type instead of another? With population density measurements by SCUBA diving and enrichment experiments with artificial dens, we concluded that the availability of solid materials necessary for den construction is a limiting factor for the distribution of O. vulgaris on soft sediment. <i>O. vulgaris</i> used four different types of den on soft sediment: well (a vertical hole in the sediment), rock/stone (the octopus uses a rock or a large stone to dig a cavity under it), shell (an empty shell is used), human origin (a solid material of human origin is used). The relative proportion of the four types of den in the areas studied was: 38.7% human origin, 29.7% well, 21.5% rock/stone, 2.9% shell. Also, 7.3% of the octopuses were found outside their den. The main types of den were found in different relative proportions in relation to the depth, the distance from shore, the octopus size and the granulometry of the sediment. ER -