Course:CONS200/2024WT1/The pros and cons of Octopus aquaculture: Is an ethical industry possible?

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Introduction

Common octopus (Octopus vulgaris).

Octopus are marine mollusks and members of the cephalopod class. They are highly intelligent creatures, medium to large in size, with eight arms, and primarily feed on shellfish and fish. Found in tropical, subtropical, and temperate waters, octopus are inhabitants of warm, coastal marine environments across the world and are abundant in areas such as the Mediterranean Sea, Japanese waters, and the Eastern Atlantic Ocean[1].

The consumption of octopus originally began in the Mediterranean and Southeast Asia, and has expanded as a commercial industry in many other parts of the world such as Europe and North America[2]. The most promising species for octopus aquaculture is the common octopus, Octopus vulgaris, which meets many requirements as a candidate for industry culture: easy adaptation to captivity conditions, acceptance of low-value natural foods, high growth rate, high reproductive rate, and high market price[3]. With worldwide demand on the rise, octopus are now the subject of large-scale aquaculture projects[4], through which production is constant and sustainable[2] in order to meet this demand. Octopus production through aquaculture works to meet consumer demand, increases economic growth, and is a staple food for various cultures around the world. However, it also has some adverse implications for the animal itself. Octopus are sentient beings, meaning they have the capacity to experience feelings and emotional reactions and to possess cognitive abilities. They are therefore vulnerable to injury and trauma when held in captivity, incapable of experiencing their natural environment, nor stimulation from their natural behaviors[2]. If provided with a rich environment that mimics their natural habitat, they can adapt well to being in captivity, however, conditions in aquaculture are generally bland and lack stimulants for the species. Octopus aquaculture has both advantages and disadvantages, these of which need to be balanced with one another; ethical and welfare concerns need to be balanced with octopus production.

The Common Octopus, Octopus Vulgaris

There are approximately 300 species of Octopus worldwide, all of which are exclusively marine, but occupy a variety of habitats ranging from intertidal pools only a few centimeters down to the abyssopelagic zone, up to 5000 meters deep[2]. Octopus are meroplanktonic, meaning they spend only one stage of their life cycles in the plankton. They generally live for a short range of one to five years. Depending on the species, octopus can lay hundreds of thousands of eggs and provide parental care for months until they hatch[2]. Many offspring do not survive to adulthood like other vertebrate and invertebrate species[2].

In aquaculture, the common octopus, Octopus vulgaris, is the species of choice for farming. It is found throughout the northeast and eastern central Atlantic Ocean, including central Atlantic islands and the Mediterranean Sea, and is absent in subpolar and polar regions[1]. This particular species is benthic, meaning it spends most of its time on the ocean floor, and inhabit rocks, coral reefs, and grass beds. The common octopus starts off as planktonic hatchlings, then grows into benthic juveniles and adults. As a benthic-dwelling species, it is selected for aquaculture because its environment can be replicated in an artificial setting[2].

Positives of Octopus Aquaculture

Include the scope/scale of the problem, intensity/frequency/severity of negative impacts, variables influencing those impacts and any other relevant information needed for understanding the issue.

Cultural Importance

Takoyaki. A cultural octopus dish in Japan.

The global seafood industry plays an essential role in providing food, jobs, and cultural significance[5]. Octopus, especially the common octopus, is one of the most commercially harvested species and holds both social and economic significance in southern Europe[6]. From a cultural perspective, octopus being rich in protein and amino acid became a cultural delicacy in the regions of Asia and the Mediterranean[7]. Spain, Italy, and Japan are among the highest consumer of octopus[8]. According to FishStatJ, a fishery statistical dataset by the National Centers for Coastal Ocean Science, by 2020, octopus production is said to have tripled over the last 50 years[6]. Aquaculture holds the potential to increase the resilience and diversification of the global seafood production system[5]. By developing sustainable aquaculture, communities in Asia and the Mediterranean can continue to celebrate their traditions and share their cultural importance with others.

Economy

Floating cages

The cultural importance of octopus fishing and the economic benefits from aquaculture have provided income for local economies[6]. Octopus can easily adapt to captivity life like aquaculture[3]. Habitats such as aquaria, cylindrical-conical containers, and floating cages are easily adaptable for octopus as they allow for fast feeding and reproduction[3]. To prevent octopus from escaping captivity areas with their ability to stick to surfaces, aquacultures tend to use a porous surface layer to surround the tank above sea level that prevents octopus from attaching to the walls[3]. Octopus generally have short life cycles with rapid growth and elevated food conversion[7]. For the economic value of feeding, the common octopus can be fed with low-value natural crustaceans and fish that can be fresh or frozen[3].  Additionally, the reproduction of octopuses in captivity allows for large hatchlings, which also allows for the trade of octopus eggs[7]. About 50% of aquaculture is internationally traded[5]. A female common octopus can produce up to 100,000-500,000 eggs[3]. In a local economy, small-scale octopus fisheries have provided jobs and have especially provided employment for women[9]. In regions near the Pacific, 56% of small-scale catches were done by women[9]. In Asia, countries like Indonesia have women employed in small-scale octopus fisheries where their income is higher than national wages[9]. With rapid growth and high survival rates, octopus biomass accumulates into a marketable commodity[7].

Mitigating Effects of Climate Change

With carbon emissions increasing global temperatures and causing ocean warming, marine species, such as octopus, are at risk of extinction and species invasions[10]. Specifically, the Mediterranean sea, the habitat of the common octopus, has seen increasing water temperatures due to human-induced global warming[11]. The Mediterranean sea has also seen effects on its salinity, water mass movement, and nutrient exchange due to climate change[11]. The common octopus has specific water quality requirements that allow them to thrive[3]. Water features such as temperature, salinity, oxygen, and ammonia are all essential to octopus livelihood[3]. Generally, the growing temperatures for octopus ranges from 10°C to 20°C, and on the higher end of the temperature range is where higher growth rates happen[3]. Temperature is also essential for females laying eggs as they require proper temperature for embryonic development[3]. The common octopus can only tolerate high levels of salts and low salinity can be fatal for the octopus[3]. The common octopus has a very short range of tolerance for salinity, and fluctuations can be stressful on octopus[3]. Salinity is another factor for the proper embryonic development of reproducing female octopus[3]. Oxygen and ammonia levels are important for octopus health as oxygen is used for digestion and ammonia passed out as waste is important to prevent toxicity[3]. Octopus aquaculture allows for proper water conditions for octopus survivability, while open oceans have more variability in their conditions[3]. A closed-off system where octopus aquaculture accounts for water variables can help mitigate the effects climate change has on the common octopus, and allow for successful reproduction and survivability of octopus species[3].

Negatives of Octopus Aquaculture

Captivity Effects on Octopus

Octopus are highly intelligent creatures and are considered among researchers to be sentient beings, possessing the ability to experience pain, anxiety, fear, and excitement. The U.K. Government, for example, declared octopus as sentient beings after passing the Animal Welfare Act in 2022 thanks to research done by Jonathan Birch, an associate professor of philosophy at London School of Economics and Political Science[12]. Because octopus have highly-developed nervous systems and are therefore highly sensitive animals, they may suffer from a lack of stimulation when held captive in a bland environment[2]. Upon experiencing stress and boredom in captivity, they may exhibit darting behaviour, or an escape response, involving fast movement that results in harm and/or ulcerations (i.e. breakage on the skin)[2]. Moreover, octopus are highly susceptible to such injuries due to their fragile skin and  not having an internal or external skeleton acting as protection. When injured, their ulcers do not heal well, and often become infected, causing either permanent damage or death when the infection spreads[4].

Dense octopus stacking on its growth

Octopus aquaculture involves densely packed population in limited space to maximize profit. Growing market demands require the octopuses to grow in space that is much smaller compared to their natural habitat. In the wild, octopuses inhabit vast territories, but in aquaculture, they are confined to much smaller spaces significantly impacting their growth and welfare.

Research reveals that higher stocking density correlates with reduced growth rates. Zheng et al. found that the denser the habitat is, the lower the body weight it was for A. fangsiao[13]. High stocking density had a significant effect on the energy acquisition and conversion of juvenile A. fangsiao [13]. The experiment by Rosas et al. reveals that when prey density and other factors were constant, the growth rate declined significantly when there were more octopuses per given area[14]. The specific growth rate when there were 140 octopuses m-2 was above 6% bw d-1, while the specific growth rate was below 4% bw d-1 when there were 280 octopuses m-2 [14]. The reduced growth rates stems from heightened competition for food and territory consequently in overcrowded environements. Competition for prey consumes a lot of energy which led to limited growth rate[14]. The overcrowded conditions result in poor octopuses’ welfare. The competition for prey in higher stocking density leaves the octopuses in more stressful conditions limiting their growth.

Aggressive behaviour

Overcrowding in aquaculture settings not only stunts growths but also triggers aggressive behaviours among octopuses. Confinement forces these solitary creatures into frequent interactions, heightening stress levels and leading to territorial disputes, cannibalism, and physical harm.[15]. Rosas et al. found that the increased frequency of encounter results in higher rates of cannibalism[14]. The ratio of attack on each species also increased with more frequent encounters[14]. Zheng et al. described extreme scenarios where multiple octopuses participated in “gang fights,” leaving victims with bite marks or broken arms and, in severe cases, causing fatalities. These behaviors highlight the physical and psychological toll of high-density environments.[13].

Aggression poses significant challenges to sustainable aquaculture. The injuries, stress, and mortality associated with such behaviors reduce productivity and compromise animal welfare. While maintaining lower stocking densities could mitigate these issues, many operations prioritize economic efficiency over ethical considerations, further amplifying these problems.

Mortality rates

Octopus aquaculture presents significant challenges due to high mortality rates, largely stemming from the species' solitary nature and sensitivity to stress in confined environments. High stocking densities exacerbate aggression and territorial conflicts, often leading to cannibalism. In the experiment conducted by Zheng et al., murder (cannibalism) and suicidal behaviour (escaping from the tank) were the two leading causes of death among octopuses[13]. As the density of the tank went up, the cannibalism and suicides were more abundant. As the density gradually increased along the four tanks, the number of death gradually increased: 3, 5, 19, 32[13]. The behaviour of both the aggressor and the victim contributes to incidents of cannibalism, and these interactions are often density-dependent[14]. Cannibalism among the octopuses is triggered by frequent interactions in confined spaces and exacerbated by competition for food and territory. Moreover, the octopus farm will be exposed to light 24 hours. The consistent exposure to light significantly increases the stress level in octopus as they tend to avoid light[15]. The suicidal behaviour results from octopuses trying to escape the light looking for dark habitat to avoid predators. The high mortality rates observed in current systems not only spotlight serious welfare concerns but also challenge the long-term viability of farming octopuses.

Consequences of feeding practices

The feeding practices of octopus aquaculture makes the consumers questions its efficiency. The feeding practice in octopus aquaculture rely heavily on wild-caught fish[16]. The dependency pressurizes wild fish populations impacting marine ecosystem. As octopuses are carnivorous species, forage fish must be used to feed the octopus aquacultures[15]. By shifting forage fish into the production of fishmeal, these resources are being depleted while at the same time impairing marine food webs and reducing ecological stability. Forage fish population is critical in transferring energy from primary producers to higher tropic-level species[15]. Unlike other sustainable aquacultures, octopus aquaculture eventually leads to overfishing and food conflict as fish and soybean are used for feedstock[15]. With nearly 20 million tonnes of fish are delivered and processed to be fed by fish, pigs and chickens annually, the inefficient manner of production concerns the production system[16]. Ironically, octopus aquaculture emerged as sustainable act to meet the market demand. However, in reality, the feeding practices are expensive and reduce the environmental stability.

Enviromental Impacts

There are many environmental controversies regarding the ethicality of octopus aquaculture, including chemical pollution, parasites and disease outbreaks, wild and farmed species, and freshwater and land usage[5]. These controversies apply to octopus aquaculture[5]. When octopus aquaculture produces waste from feed left uneaten by octopus and medication used for octopus health, it leads to excess nutrients and chemicals in the ocean[5]. This can lead to eutrophication, which is when excess nutrients are released into the water and lead to algae blooms depleting oxygen and killing all marine life[17]. Chemicals from medication can leak into oceans and negatively affect other marine species and the surrounding environment[5]. Aquaculture medication has also been found in soil and waterways and causes ecosystem imbalance[17]. With the lack of diversity and adaptations within octopus aquaculture, diseases and parasites are issues that need to be addressed to sustain an ethical environment with octopus aquaculture[5]. Diseases and parasite outbreaks lead to threats to wild octopus species, as farmed octopus can escape and increase competition with wild species[5]. Lastly, operating octopus aquaculture utilizes land and freshwater, which are limited[5]. Mangrove forests, an ecologically important system home to many diverse species, have been deforested to make room for aquaculture in Asia[17]. Overusing land to operate octopus aquaculture and filling tanks with water to their proper conditions leads to resource competition and overall affects biodiversity[5].

Current Remedial Actions

Research regarding the aforementioned problem of lack of stimulation in captivity suggests that, to avoid increased mortality, octopus, as highly intelligent creatures with a complex nervous system and intricate behavioral patterns, require some sort of stimulation or enrichment regarding their natural environment and day-to-day behaviors. Sentience in octopus, a highly debated topic in the veterinary community, is at the center of addressing this issue. Evidence from various studies over time suggests that octopus, or rather cephalopods in general, are sentient beings due to their observed cognitive abilities such as puzzle solving and their ability to adapt quickly to different tasks given them as per past experimentation. In light of this debate, scientists propose the incorporation of environmental enrichment into octopus aquaculture. Environmental enrichment can be defined as the addition of new environmental stimuli to meet the physiological and behavioral needs of the farmed species, in this case octopus [1]. It acts as a remedy to the boredom and curiosity octopus experience when kept in captivity, and can take the form of puzzles, interactable objects [2], hiding places, or habitat-mimicking objects such as sand, rocks, or coral. This kind of enrichment improves feeding behavior and prevents injuries [2], facilitates biological functioning, and may therefore increase the chance of success in the rate of species survival in octopus aquaculture operations. Many environmental enrichment practices on terrestrial species such as rats, chimpanzees, and black bears have been proven successful [1], the same levels of environmental enrichment practice have not yet been applied to cephalopods such as the octopus species. Being a highly intelligent species, especially exhibiting mostly vision-dependent intelligent behaviours, the methods of implementing enrichment would need to follow this line of reasoning. Focusing on stimulating visual problem solving abilities such as spatial learning, associative learning, and observational learning [1] enhances the captivity and aquaculture to provide an environment that promotes mental engagement to reduce stress-related behaviors. In many regions, issues regarding cost and sterilization of enrichment equipment to prevent disease transmission do exist [2]. Moreover, the implementation of environmental enrichment has not been yet adopted by many organizations [2]. Further, there is no standardized framework or general organization governing aquaculture practices, resulting in variable ethical care and treatment for octopus aquaculture across different regions [2]. In many areas, ethical and sustainable aquaculture practices have been underway. Essentially, measures to adapt these practices address both current criticisms, and solutions to the challenges associated with aquaculture that exists today. Considerations include selecting appropriate farming sites and species, implementing optimal culture systems, adopting the best feed and feeding practices, utilizing bioremediation systems, reducing reliance on fishmeal and fish oil, managing effluents effectively, attaining sustainability certifications, and advancing research and legislation to assess and mitigate aquaculture impacts [17]. One of the main goals in cephalopod aquaculture is to minimize the amount of octopus that are being harvested. Because octopus fishing is also culturally significant to many places in Europe, many artisanal fisheries in Europe have been attempting to regulate these actions by integrating value analysis to the product, not just by market value [6]. By integrating and conveying knowledge, as well as stakeholder learning exchanges value product diversification, the goal of market development will be fostered by an environment that benefits all participants [6]. Ultimately, addressing the ethics of octopus aquaculture is the key to sustainable development that requires a multifaceted approach. While budgets and ethical consideration may be challenging, new ideas and technologies such as environmental enrichment and stimuli, stakeholder collaboration, and overall thinking intelligently when it comes to farming where, why and how, the future of octopus aquaculture is headed for a more ecologically balanced and humane future.

Conclusion

Octopus aquaculture is a rapidly growing industry driven by increasing global demand and its potential to support economic growth and cultural traditions. Among many species, the common octopus (Octopus vulgaris) is the primary species farmed due to its adaptability, fast growth, and high market value. Nevertheless, the high level of intelligence among octopus has raised ethical concerns about the aquaculture practice regarding animal welfare, as octopuses often face stress and injury in overcrowded and unstimulating captive environments. Efforts to address these issues, such as implementing environmental enrichment strategies, have shown promise but are not yet widely adopted due to costs and lack of standardized practices. Additionally, the environmental impacts of aquaculture, including ecosystem disruption and resource competition, highlight the importance of developing sustainable and ethical aquaculture practices. As the industry continues to evolve, striking a balance between meeting global demand and ensuring ethical and sustainable operations remains a critical priority, and is a path that with collaborative efforts as well as innovative solutions, has the potential to achieve a responsible and resilient future in aquaculture.

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Rosa, Rui; Roura, Alvaro; Gleadall, Ian G.; Guerra, Angel; Gonzalez, Angel F.; Lopes, Vanessa M.; Pereira, Joao; Pierce, Graham J.; Sampaio, Edwardo (2024). "Octopus vulgaris, the common octopus". Octopus Biology and Ecology: 187–216 – via Elsevier Science Direct. Cite error: Invalid <ref> tag; name ":11" defined multiple times with different content
  2. ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 Powell, Ashley L. (2022). "Octopus aquaculture: Welfare practices and challenges". The Canadian Veterinary Journal. 63: 1072 – via National Library of Medicine. Cite error: Invalid <ref> tag; name ":12" defined multiple times with different content
  3. ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 3.12 3.13 3.14 3.15 Vaz-Pires, Paulo; Seixas, Pedro; Barbosa, Alexandra (2004). "Aquaculture potential of the common octopus (Octopus vulgaris Cuvier, 1797): a review". Aquaculture. 238.
  4. ↑ 4.0 4.1 Natali, Meganne; Gisie, Laure (2024). "Cephalopod Welfare and Laws in Industrial Aquaculture: Exploring the Irrelevance of Octopus Farming Projects". Derecho Animal - Animal Legal and Policy Studies. 2: 124–153 – via DALPS.
  5. ↑ 5.00 5.01 5.02 5.03 5.04 5.05 5.06 5.07 5.08 5.09 5.10 Lam, Mimi E. (2016). "The Ethics and Sustainability of Capture Fisheries and Aquaculture". Journal of Agricultural and Environmental Ethics. 29: 35–65.
  6. ↑ 6.0 6.1 6.2 6.3 6.4 Ainsworth, Gillian B.; Pita, Pablo; Pita, Cristina; Roumbedakis, Katina; Pierce, Graham J.; Longo, Catherine; Verutes, Gregory; Fonsec, Tereza; Castelo, Daniela (2023). "Identifying sustainability priorities among value chain actors in artisanal common octopus fisheries". Reviews in fish biology and fisheries. 33: 669–698.
  7. ↑ 7.0 7.1 7.2 7.3 Villanueva, Roger; Sykes, António V.; Vidal, Erica A.G.; Rosas, Carlos; Nabhitabhata, Jaruwat; Fuentes, Lidia; Iglesias, José (2014). "Current Status and Future Challenges in Cephalopod Culture". Cephalopod Culture. 1: 479–489.
  8. ↑ Pita, Cristina; Roumbedakis, Katina; Fonseca, Teresa; Matos, Fábio L.; Pereira, João; Villasante, Sebastián; Pita, Pablo; Bellido, José Maria; Gonzalez, Angel F. (2021). "Fisheries for common octopus in Europe: socioeconomic importance and management". Fisheries Research. 235: 105820.
  9. ↑ 9.0 9.1 9.2 Willer, David F.; Aldridge, David C.; Gough, Charlie; Kincaid, Kate (2023). "Small-scale octopus fishery operations enable environmentally and socioeconomically sustainable sourcing of nutrients under climate change". Nature Food. 1: 1–11.
  10. ↑ Lima, Françoise D.; Ángeles-González, Luis Enrique; Leite, Tatiana S.; Lima, Sergio M. Q. (2020). "Global climate changes over time shape the environmental niche distribution of Octopus insularis in the Atlantic Ocean". Marine Ecology Progress Series. 652: 111–121.
  11. ↑ 11.0 11.1 Lejeusne, Christophe; Chevaldonné, Pierre; Pergent-Martini, Christine; Boudouresque, Charles F.; Pérez, Thierry (2010). "Climate change effects on a miniature ocean: the highly diverse, highly impacted Mediterranean Sea". Trends in Ecology & Evolution. 25: 250–260.
  12. ↑ Birch, Jonathan (2022). "The science of feeling: why octopuses, lobsters and crabs require animal welfare protection". The London School of Economics and Political Science.
  13. ↑ 13.0 13.1 13.2 13.3 13.4 Zheng, Jian; Qian, Yaosen; Zheng, Xiaodong (2023). "Effects of stocking density on juvenile amphioctopus fangsiao (mollusca: Cephalopodasca: Cephalopoda): Survival, growth, behavior, stress tolerance and biochemical response". Aquaculture. 567 – via Elsevier Science Direct.
  14. ↑ 14.0 14.1 14.2 14.3 14.4 14.5 Rosas, Carlos; Mascaró, Maite; Mena, Richard; Caamal-Monsreal, Claudia; Domingues, Pedro (2014). "Effects of different prey and rearing densities on growth and survival of octopus maya hatchlings". Fisheries and Aquaculture Journal. 5 – via Omits Publishing Group.
  15. ↑ 15.0 15.1 15.2 15.3 15.4 Lara, Elena (March 2023). "Octopus factory farming: A recipe for disaster". Compassion in World Farming and Eurogroup for Animals.
  16. ↑ 16.0 16.1 Cashion, Tim; Le Manach, Frédéric; Zeller, Dirk; Pauly, Daniel (September 2017). "Most fish destined for fishmeal production are food‐grade fish". Fish and fisheries. 18 – via Wiley.
  17. ↑ 17.0 17.1 17.2 17.3 Martinez-Porchas, Marcel; Martinez-Cordova, Luis R. (2012). "World aquaculture: environmental impacts and troubleshooting alternatives". The Scientific World Journal. 1: 389623.
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