Den-Associated Behavior of Octopus rubescens Revealed by a Motion-Activated Camera Trap System

Abstract

Dens are a crucial component of the life history of most shallow water octopuses. However, den usage dynamics have only been explored in a few species over relatively short durations, and Octopus rubescens denning behavior has never been explored in situ. We built four underwater camera traps to observe the behavior of Octopus rubescens in and around their dens. To distinguish individuals, octopuses were captured and given a unique identifiable visible implant elastomer tag on the dorsal side of their mantle. After being tagged and photographed, each octopus was released back to its original capture site within its original den bottle. The site is unique in that octopuses reside almost exclusively in discarded bottles, therefore aiding in locating and monitoring dens. Motion-activated cameras were suspended in a metal field of view above bottle dens of released octopuses to observe den associated behaviors. Cameras were regularly retrieved and replaced to allow continuous monitoring of den locations in 71-hour intervals for over a month. We found that O. rubescens was primarily active during the day and had frequent interactions with conspecifics (other members within the species). We also found that rockfish and red rock crabs tended to frequent den locations more often when octopuses were not present, while kelp greenling both visited dens more frequently and stayed longer when octopuses were present. Our results demonstrate the utility of motion-activated camera traps for behavioral and ecological studies of nearshore mobile organisms.

Bathyal octopus, Muusoctopus leioderma, living in a world of acid: First recordings of routine metabolic rate and critical oxygen partial pressures of a deep water species under elevated pCO2

“…These depths are shallower than the depths of OMZs along the west coast of North America typically occur ( Kamykowski and Zentara, 1990 ). Like other shallow water species O. rubescens has an ink sac, performs dynamic skin color and texture change, ( Packard and Hochberg, 1977 ), and is most active during the day ( Humbert et al, 2022 ). This species and its shallow water congeners have not experienced the same environmental hypoxia and hypercapnia of species who live at depths corresponding to OMZs and thus may not have the same physiological adaptations.…”

“…Octopus rubescens, like other species of octopus, spends the majority of each 1 day period in a den ( Kayes, 1973 ; Mather, 1988 ; Humbert et al, 2022 ). While their natural dens in the wild have not been studied extensively, they are regularly observed using rocky outcroppings, large empty barnacle shells, beer bottles, and other hard containers of sufficient size ( Anderson, 1997 ; Anderson et al, 1999 ) .…”

The Open-source Camera Trap for Organism Presence and Underwater Surveillance (OCTOPUS)

“…We tested the performance of this camera system in one of the most challenging situations for an aquatic camera trap: tracking the movements of a highly mobile animal (octopuses) in a high-current location. Four camera systems were built and tested at Rosario Beach Marine Laboratory followed by a series of field deployments at Driftwood Park, in Island County, Washington state to monitor ruby octopuses ( Octopus rubescens ) at den sites [10] . Driftwood Park is located on Admiralty Inlet, one of only two inlets to the Puget Sound, Washington, USA, and therefore experiences significant and frequent tidal currents.…”

“…System settings for these field deployments were configured to utilize auto exposure without auto contrast, an ISO of 800, image quality of 95 and monochrome image depth. The data collected led to insights into the diel activity cycles of this octopus species and revealed new inter-species interactions, specifically with kelp greenlings, examples of these interactions can be found following the attached link [10] .…”

Octospy: What Octopus insularis do in their dens

“…In the past dozen years, laboratory studies have been conducted on a broad range of octopus behaviors, including sociality (Edsinger & Dölen, 2018), sleep (Medeiros et al, 2020), motor control (Gutnick et al, 2020), problem‐solving (Richter et al, 2016), personality (Pronk et al, 2010), and the ability to recognize individual conspecifics (Tricarico et al, 2011) as well as individual humans (Anderson et al, 2010), among others. Octopus have also been studied in their natural habitats, including determination of prey choice and its correlates with individual personality (Scheel, Leite, et al, 2017), responses to novel objects as well as simulated prey items (realistic rubber crab) and conspecifics (mirror; O'Brien, Di Miccoli, & Fiorito, 2021), interaction and communication with conspecifics (Godfrey‐Smith et al, 2022; Humbert et al, 2022; O'Brien, Di Miccoli, & Fiorito, 2021; O'Brien, Taylor, et al, 2021; Scheel et al, 2016; Scheel, Chancellor, et al, 2017), interactions and niche partitioning with sympatric octopus species (Bennice et al, 2019; Huffard & Bartick, 2015), interactions with fish (Humbert et al, 2022; Sampaio et al, 2020), ecosystem engineering (Scheel et al, 2014, 2018), and habitat use (Scheel & Bisson, 2012).…”