In an octopus's garden in the shade: Underwater image analysis of litter use by benthic octopuses

Interaction of elasmobranchs with litter in South Brazil: ingestion and oviposition patterns

Elasmobranchs, one of the most endangered animal groups, have been affected by different anthropogenic stressors, including marine litter. To better understand the interactions of elasmobranchs with litter we analyzed the gastrointestinal tract of sharks and examined skate nest composition in southern Brazil. Among 47 sharks caught in longline fisheries, three had ingested mesoplastic items (FO = 6.4 %); a subsample of 18 of these sharks was assessed for microplastic ingestion, revealing 34 microplastics in 12 individuals (FO = 66 %). Gillnet-captured sharks (n = 7) only ingested three microplastics (FO = 42.85 %). Sixteen skate nests examined for litter interaction presented a total of 269 egg capsules and 1676 litter items. The FO of litter in nests was 100 %, with plastic being the predominant material (96.71 %), mainly fishing lines (85.98 %). While litter ingestion by sharks was less frequent than other groups, litter prevalence in skate nests was high and primarily linked to fishing activities.

What lies underneath: Comparison among beach litter in the underwater bathing area and exposed beach

The standard techniques for monitoring beach litter focus on the litter that is accumulated on beaches. Therefore, the underwater bathing area is usually overlooked. Our study aims to start the discussion about the litter in the bathing area, an important connection between the exposed beach and the ocean. We aimed to compare sampling methodologies between the underwater bathing area and the exposed beach. We highlighted litter's similarities and differences regarding the amount, material, possible sources, and interaction with the biota. We also performed a brand audit on the underwater bathing area litter. In the underwater region, 106 items were collected while 1706 items were collected from the exposed beach region. Plastic was the dominant type of material in both sites, exposed beach (89.92 %) and bathing area (83.96 %). The litter's possible source was different. In the underwater bathing area was more related to food packages (couscous, rice). On the other hand, litter on the exposed beach was associated with beach use (single-use plastic such as plastic cups). The brand audit identified 21 companies, whereby most brands were Brazilian and food-related. Regarding interactions with the biota, the litter in the bathing area had more bio-fouling (87.73 %) than the litter collected on the exposed beach (10.00 %). Information about bathing area litter can be useful to draw different management strategies. Due to the differences in litter types and behavior between the two sites, the same mitigation strategies might not be equally efficient.

Understanding the interactions between cephalopods and marine litter: A research evaluation with identification of gaps and future perspectives

Litter is known to negatively affect numerous marine organisms, but the extent of such impacts is not well known for several groups, including cephalopods. Considering the ecological, behavioral and economic importance of these animals, we reviewed the types of interactions between cephalopods and litter in the scientific literature, to evaluate impacts and knowledge gaps. We found 30 papers, which included records of microplastic ingestion and the transfer of synthetic microfibers along the food web. The largest number of records involved litter use as shelter, and the common octopus was the most frequent species. At first sight, litter use as shelter could appear to be a potential positive effect, but it is necessary to clarify the implications of this choice and its long-term consequences. Regarding ingestion and trophic transfer, further research is needed to elucidate its occurrence and impacts on cephalopods and their predators, including humans.

The Case for Octopus Consciousness: Valence

Octopuses may demonstrate perceptual richness, neural unity, temporality, and finally, valence or affective evaluation, as the neural basis for consciousness. Octopuses attach a positive valence to food as 'specializing generalists' with long-term learning and flexible choices. They value shelter, yet modify, adapt and even transport it where necessary. They attach a negative valence to what may be described as pain, monitoring and protecting the damaged area and learning to associate locations with pain relief. Finally and surprisingly, octopuses attach a negative value to uncertainty so that they explore their environment before exploiting certain aspects of it and even exhibit motor play. This series of four papers, culminating in the present one, demonstrates in detail why the Cambridge Declaration of Consciousness has suggested octopuses might have the substrate for consciousness, although it is likely not similar to or as complex as that shown by 'higher' vertebrate lineages.

Den Associated Behavior of Octopus Rubescens Revealed By a Motion-Activated Camera Trap System

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.