Navigating towards resilient relationships with kelp

Abstract

As interest in kelp mariculture increases globally, we risk disrupting critical social-ecological relationships with kelps and the temperate, nearshore rocky reef ecosystems they shape. Using Canada’s Pacific coast as an example, we identify opportunities for transforming kelp mariculture amidst climate change, social inequities, and socio-political uncertainty. Just transitions towards regenerative kelp economies will require balancing diverse objectives among actors, equitably reforming laws and governance structures, and integrating coastal management practices.

Introduction

Economic and political pressures to develop ocean industries are intensifying amidst a rapidly changing climate, producing novel social-ecological risks, uncertainties, and opportunities¹. Within this dynamic seascape, addressing emergent challenges is complicated by interdependencies, cross-scale interactions, non-linear responses, and conflicting values and objectives among actors. Transformative and integrative solutions are needed to support resilient and regenerative ocean economies^1,2, lest we create gilded traps of ocean industry that yield short-term material benefits for a few but risk long-term social and ecological poverty³.

Global sustainability goals (e.g., United Nations Sustainable Development Goals) and blue economy initiatives⁴ are prompting the development of kelp mariculture—practices including wild kelp harvest and kelp cultivation—for sustainable aquatic food production, blue carbon markets, ecosystem restoration, and other climate-friendly applications^5,6. Kelps are increasingly touted as a “climate solution” due to their low aquaculture emissions⁷, role in carbon sequestration^8–10, and potential to offset more carbon- and land-intensive materials in commercial applications^11–13. However, kelps are directly and indirectly susceptible to increasing ocean temperatures and intensifying heatwaves caused by anthropogenic climate change¹⁴. The negative effects of climate change, which are regionally variable, will shape the future distribution and success of kelp mariculture activities^15–17. We foresee that this combination of global pressures and local limits to growth will generate a “squeeze”, with kelps increasingly caught between the weight of expectation created by climate-reactionary economic policy and their own physiological limits within a swiftly warming seascape.

Drawing on a series of intersectoral discussions among natural and social scientists, Indigenous and settler practitioners, and kelp mariculture industry members with diverse values, perspectives, and objectives, we conceptualize kelp mariculture using a systems approach to propose actions that may address the causes and consequences of this “squeeze”. First, we describe key interactions and scales within kelp mariculture systems and discuss challenges stemming from system complexities. Then, we articulate opportunities and uncertainties and suggest interventions at key leverage points for navigating towards a regenerative kelp economy grounded in resilient, reciprocal relationships among system components¹⁸. We use Canada’s Pacific coast as a case study, a system that is newly emergent among kelp industries globally, with many development trajectories possible, and with many enabling conditions for success^19,20, including progress towards equitable marine co-governance processes with Indigenous Nations, provincial, and federal governments²¹ amid regionally variable effects of climate change²². While our suggested interventions are place-based, which inherently limits their transferability to other systems^23,24, we draw generalities that may apply to kelp mariculture globally.

Viewing kelp mariculture through a systems lens

Within temperate coastal waters worldwide, kelp wild harvest and cultivation can vary in intensity from place-based to industrialized scales, with differing ecological effects and thresholds among mariculture practices. For instance, highly size-selective, moderate harvest of wild kelps may promote frond growth^25,26, while indiscriminate, intensive wild harvest may reduce the biomass of kelp-associated species²⁷. Similarly, kelp cultivation can produce both positive and negative ecological effects. For example, kelp farms may provide novel kelp canopy habitat and physical infrastructure that can attract transient or resident fish, mobile invertebrates, and benthic infauna^28–30, and fixation of nutrients and contaminants by cultivated kelps can combat eutrophication and pollution along urbanized coastlines^31–33. However, without ecologically informed implementation, kelp cultivation can also shade out or smother the benthos^28,32, genetically pollute wild kelp populations through spores from domesticated cultivars^32,34, or locally compete with phytoplankton for nutrients^32,35,36. The positive and negative effects of cultivation can be expected to scale with intensity (i.e., farm size and density)^36,37, and such scaling relationships may be non-linear³⁸.

Across this gradient of intensity, kelp mariculture interacts with ecological and social variables at multiple spatial scales. Kelp distribution and productivity are locally constrained by environmental conditions³⁹, grazing dynamics⁴⁰, and harvest regimes^25,27. As with other natural resource relationships, industry growth—partly driven by global sustainability goals—is reshaping place-based, reciprocal human-kelp relationships as kelp is extracted, processed, and distributed to more distant communities⁴¹. Governance structures at local, regional, and national levels, along with the values motivating these structures, mediate many of the ecological and social relationships within kelp mariculture systems.

We characterize kelp mariculture on Canada’s Pacific coast as a case study that may exemplify aspects of other kelp mariculture systems (Fig. 1). These temperate waters host over a quarter of the world’s known kelp species^42,43. Here, climate impacts on wild kelps are spatially variable; kelp populations in warming hotspots have declined or become locally extirpated, while populations elsewhere have remained resilient to climatic disturbances^22,44,45. Indigenous people have lived along Canada’s Pacific coast for at least 14,000 years⁴⁶ and have developed longstanding, reciprocal relationships with kelps^26,47–49. Within this ecological and historical context, commercial kelp mariculture is a growing industry. On this coast, commercial wild kelp harvest occurs at small to medium scales³², with over 500 metric tons of harvest reported in 2024 (K.A.P., personal communication). Cultivation occurs at small scales; currently, the largest licensed farm is 0.4 km², with no legislated limit on farm size³². The potential ecological effects of cultivation on coastal ecosystems remain understudied along this coastline, and while negative effects are generally predicted to be of low to moderate likelihood, their consequences are potentially high³². In the province of British Columbia (BC), ocean governance is siloed among governance institutions^50,51. Kelp mariculture activities are primarily managed by the Province of BC in consultation with coastal First Nations and federal agencies³². Marine plans co-developed by Indigenous Nations and the Province of BC²¹ and Canadian blue economic strategy⁴ have highlighted the potential for kelp mariculture expansion.

Fig. 1. Major social-ecological relationships and external disturbances influencing kelp mariculture activities on Canada’s Pacific coast.

Kelp social-ecological systems are represented within the light grey boundary, with relationships between variables represented by arrows. Kelp mariculture includes wild harvest and cultivation, and both modes of mariculture span an intensity gradient from small-scale, place-based practices to large-scale, industrialized practices. Variables operate across spatial scales from local to global, with interactions and feedbacks spanning spatial scales. The UN Sustainable Development Goals color wheel icon was downloaded from https://www.un.org/sustainabledevelopment. The content of this publication has not been approved by the United Nations and does not reflect the views of the United Nations or its officials or Member States.

Current and growing challenges within kelp mariculture

Human societies have harvested kelp for over 12,000 years⁵², but the advent of commercial mariculture and colonial governance structures is challenging ancestral relationships with kelp worldwide. Kelps have long been valued by Indigenous peoples and place-based societies as fertilizer, medicine, tools, and the foundation of food systems^47,48,53. Today, kelps are increasingly used for diverse commercial applications, including pharmaceuticals, cosmetics, biostimulants, biomaterials, and feed additives⁵⁴. Ancestral and industrialized human-kelp relationships may be shaped by vastly different worldviews and values. Relationships between Indigenous peoples of the northwest coast of North America and other-than-human species are guided by deeply held values enacted through governance principles of respect, responsibility, reciprocity, interconnectedness, and balance^55,56. These Indigenous principles are reflected in how kelp is valued, for example, for its existence, for future generations, and as kin⁴⁷. When these values, and the management objectives they underpin, conflict with values of kelp as a resource for job and income generation, trade-offs manifest, and tension can build within management spaces², as documented for Indigenous communities enmeshed in the gilded trap of salmon farming⁵⁷.

Resolving such conflicts is difficult due to underlying inequities and power imbalances between nation-states, industry actors, and traditional caretakers and rightsholders. Ongoing colonial harms within Canada have suppressed the rights and responsibilities of coastal Indigenous Nations, restricting their ability to practice ancestral relationships with resources, including kelp, which has had detrimental impacts on cultural identity and human health⁵⁸. While progress is being made towards formalized ocean co-management between the Province of BC and coastal Indigenous Nations^21,59,60, the policy landscape remains volatile. The province currently has a duty to consult with Indigenous Nations when developing kelp mariculture policy and issuing harvest licenses and farm tenures³², moving toward consensus where possible, with industry proponents expected to do the same. However, at this time, consultation does not constitute joint decision-making as mandated by BC’s Declaration on the Rights of Indigenous Peoples Act (DRIPA), and while actions have been recommended to align current provincial practices with DRIPA⁶⁰, this nexus of policy and politics remains unstable.

Despite narratives about the potential for kelp mariculture to empower coastal economies, industry growth along Canada's Pacific coast is constrained by market, policy, and supply chain challenges shared by other emergent kelp sectors globally. Within North America’s largest kelp economy, the Gulf of Maine’s sugar kelp industry, farms are small, labor costs are high, and processing capacity is limited, translating into a prohibitively high per-unit cost of production for biomass-intensive applications such as biofuels and a current focus on kelp as a value-added ingredient in artisanal foods and cosmetics^61–65. In BC, purpose-built policy instruments for regulating kelp mariculture are lacking³², which both increases potential environmental risk and results in an opaque and lengthy permitting process for industry proponents^32,61. For operators based in remote coastal communities, accessing kelp nurseries and sufficiently large processing facilities can be logistically complex and costly^32,61. Taken together, these barriers can impact profitability⁶⁶, thereby limiting investment, innovation, and industry development⁶⁷. Today, BC’s kelp mariculture sector is dominated by wild harvest³², but greater cultivation will be needed to grow production without overharvesting wild populations. While increasing farm size and processing capacity to industrial levels present in Asia could increase profitability as the material costs of cultivation are spread across more product^68,69, social license would be needed to accommodate accompanying shifts in coastal space use and potential increased risks to coastal ecosystems, which has not been evident within BC or other emergent kelp economies, including the Gulf of Maine^43,70–72. Kelp mariculture development in BC must be strategic to ensure that economic viability is achieved within ecological limits and what is considered socially acceptable.

Imagining a regenerative kelp future: opportunities and uncertainties

Although kelp mariculture faces many challenges, opportunities exist to cultivate regenerative human-kelp relationships that balance profit with ecological health and cultural integrity. Regenerative economies are those that enable reciprocal, nurturing relationships between ecosystems and humans for mutual flourishing and value the wellbeing of human and other-than-human communities, beyond solely customers and shareholders^2,18,73. This mode of development prioritizes equity and respects ecological limits to growth, which necessitates a holistic understanding of and partnership with place⁷³. Embracing a regenerative approach for kelp mariculture may help balance diverse objectives, including food sovereignty, cultural uses, and economic empowerment for coastal communities, ultimately yielding a more valuable industry when economic, social, and ecological dimensions are considered together⁷³. While a goal of regenerative development is to advance social equity, legal reforms are needed to correct power imbalances within governance structures and ensure economic development is truly equitable.

Governance institutions, as key intermediaries between industry, coastal communities, and ecosystems, can facilitate just transitions towards regenerative kelp mariculture. Just transitions seek to utilize or transform existing systems to advance practices that equitably respect governance structures and a plurality of worldviews, knowledge, priorities, cultures, and legal systems, invite inclusive decision-making, and fairly distribute the benefits and harms of decisions among groups⁷⁴. For kelp mariculture, just transitions can be enacted by reforming laws and policies to empower local decision-makers within management spaces, as is happening within BC through the co-development of the provincial Coastal Marine Strategy with Indigenous Nations⁵⁹—a blueprint for implementing ecosystem-based coastal stewardship at a provincial level— and of regional marine plans via an Indigenous and provincial partnership²¹. Clear, strong policy guardrails and holistic, science-informed management strategies co-developed with local leadership are essential for governance institutions to establish both social license with coastal communities and a resilient kelp sector.

Because of uncertainties associated with climate change, ecological impacts, and market forces, kelp mariculture under business-as-usual development may represent a gilded trap³. That is, mariculture activities may initially proliferate, requiring businesses and communities to invest in the infrastructure, equipment, and permits needed for kelp mariculture. However, if environmental, economic, and policy conditions do not support ecologically and socially sustainable outcomes, then kelp mariculture may underdeliver on its promising rhetoric of economic empowerment for coastal communities or, at worst, result in ecological and social harms. In BC, continued kelp species losses are anticipated under growing climate perturbations¹⁹, making the long-term outlook for kelp mariculture unclear. Elsewhere, others have proposed “future-proofing” kelp cultivation and restoration through selectively breeding warm-adapted genotypes^34,75 and thermally priming juvenile kelps to increase resilience to marine heatwaves⁷⁶, but it is unclear if such interventions are scalable, can keep pace with climate impacts, or could have their own unintended consequences if enacted. The ecological effects of kelp mariculture—and how these effects will be mediated by climate change—remain understudied^9,28,32. Long-term economic viability will require greater domestic demand for kelp products or an ability to access and compete within international markets, but the pace of industry development remains uncertain. Developing kelp mariculture against this backdrop of known and unknown risks challenges communities, regulators, and businesses, and interventions are needed now to ensure future sustainability.

Navigating towards a regenerative kelp economy for Canada’s Pacific coast

System transformations, such as those required to shift towards a regenerative development paradigm, can be accomplished by intervening at multiple leverage points⁷⁷. These interventions range from those that are more easily enacted and result in incremental changes to those that are more difficult to enact but can generate radical changes⁷⁸. Here, we propose actions to navigate towards more resilient relationships with kelps on Canada’s Pacific coast (Fig. 2), which may apply to emergent kelp mariculture systems more broadly.

Fig. 2. Possible trajectories of kelp mariculture systems along Canada’s Pacific coast through time.

Industry value will grow from the present (left blue circle) to possible future states (right divided circles). Possible futures differ in their relative social, ecological, and economic value (represented through circle divisions) and in their social-ecological resilience. To achieve a more regenerative future, interventions (central wedge) must be enacted over time, concurrently or sequentially, at multiple leverage points within kelp mariculture systems.

Pluralism in worldviews

Scholars increasingly recognize the need for collective leadership and transdisciplinary partnerships to address complex challenges in sustainability^79,80. Academic and industry leaders recently drafted a “Seaweed Manifesto” outlining United Nations SDGs advanced by the seaweed industry, barriers to industry success, and strategies for change⁶. However, enacting global goals necessitates downscaling them to a local level, which requires concordance with community priorities, values, and objectives⁸¹. Thus, to responsibly develop kelp mariculture, we must empower local communities within decision-making processes and balance diverse objectives for the future among actors^32,82. This process will require acknowledging pluralism in worldviews and remaining transparent about the trade-offs involved in pursuing different objectives. The recent creation of Alaska Mariculture Development Plan at the direction of state government exemplifies these necessary intersectoral dialogues; this plan outlines guiding principles for growing a profitable mariculture sector that complements existing coastal uses, preserves ecosystem integrity, and benefits Alaska Natives⁸³. In BC, a similar process could build upon the visions articulated by coastal Indigenous Nations and the provincial government when co-developing regional marine spatial plans²¹ and the BC Coastal Marine Strategy⁵⁹ to chart an ecologically sustainable and socially just path forward for kelp mariculture.

Legal and policy reforms

Enacting a just transition that acknowledges diverse worldviews and objectives requires purpose-built, equitable policies rooted in local knowledge and current science. At present, provincial regulators in BC must contend with rigid, now-outdated, colonial legislation (e.g., Land Act, Fish and Seafood Act) when issuing harvest and cultivation licenses³². These laws do not explicitly or comprehensively address kelp mariculture, creating regulatory loopholes³². The potential ecological risks of kelp mariculture are currently mitigated using conditions of license, which prevent the cultivation of non-native species, require diverse, locally sourced broodstock, and delineate ecologically appropriate areas for farm siting, among other guidelines, a system which relies on good-faith participation by industry actors. However, there are limited mechanisms for reporting and enforcement, which may challenge compliance as the sector grows³² unless communities are invited to inform regulations and legitimized and resourced to enforce them, as has been effective for nearshore fisheries in Chile and Mexico^53,84. While the Province of BC is updating marine plant policies to tighten regulations, underlying legal frameworks do not yet recognize Indigenous Nations as equal decision makers. Though processes for joint decision-making between the Council of the Haida Nation and provincial and federal colonial governments have recently been formalized, broader proposals to align the Land Act with DRIPA and allow for joint decision-making between provincial and Indigenous managers on public land use—including marine tenures—have stalled as of 2024. A just transition within kelp mariculture requires that the Province of BC move beyond Indigenous consultation and towards comprehensive co-governance agreements for water, land, and resource management in Indigenous territories. In this way, historically marginalized Indigenous values, knowledge, objectives, and sovereignty can be upheld within decision-making processes to ensure that the risks and benefits of kelp mariculture are equitably distributed among actors.

Polycentric governance

Within BC, enabling joint decision-making between Indigenous and provincial decision makers can allow collaborative, polycentric management of kelp resources, which is currently complicated by jurisdictional overlaps between Indigenous, provincial, and federal governance institutions³². Effective polycentric and collaborative governance systems can help reconcile these overlaps, mobilizing the innate strengths of distinct governance institutions around a common purpose by devolving decision-making authority to local scales and among semi-autonomous groups while clearly delineating and coordinating their responsibilities⁸⁵. Globally, community-implemented management systems rooted in local knowledge have proven effective at stewarding collective resources, particularly when facilitated by larger-scale governance processes that can provide venues for exchanging technical expertise and sharing information, legitimize and amplify community objectives, and support enforcement of those objectives^84,86. For instance, Chilean and Japanese artisanal kelp fishers and fishing cooperatives in Baja California, Mexico have maintained high densities of kelps within areas where centralized governments have conferred exclusive rights to customary harvest of kelps and kelp-associated invertebrates^53,84,87,88. In BC, coastal Indigenous Nations have stewarded their resources within spatially explicit areas for millennia^48,49,55,56—including through periods of climate disturbance and swift sea level change⁸⁹—and manage at scales relevant to ecological dynamics, making them ideally suited to detecting, understanding, and adapting to changing conditions⁸⁵. Along BC’s Central Coast, the Coastal Guardian Watchmen program has demonstrated that local Indigenous management can decrease the delay between observing climate impacts on kelps and mobilizing a response⁹⁰. Meanwhile, the Province of BC and multi-Nation organizations are well-positioned to coordinate regional management efforts and provide technical and logistical support, as has been demonstrated through recent co-developed management plans and coastal strategies^21,59,91. We imagine a future where autonomous, yet coordinated coastal Nations continue to steward marine ecosystems, including kelps, according to ancestral governance principles honed over millennia, with regional collaborative governance institutions assisting local actions, providing resources and technical support where needed, and facilitating equitable and shared decision-making at coast-wide scales. Poorly delineated polycentric governance systems can stymie community-led industry growth, as in coastal Norway, where federal top-down conservation priorities have conflicted with municipal objectives to grow local marine industry, despite a shared responsibility for coastal zone planning⁹². However, with communication and collaboration among individual institutions, clarifying an equitable polycentric governance approach for kelp mariculture in BC can guard against power inequities and enable effective place-based management while supporting the provincial government’s mandate to align existing policy and practice with DRIPA⁶⁰.

Adaptive management

To increase the safe operating space for kelps amidst rapid ocean change, adaptive management, where interventions are treated as experiments and regularly evaluated for effectiveness, could permit a nimbler response to unexpected system changes⁹³. From BC to Baja California, Mexico, place-based management actions have demonstrated potential to increase the resilience of kelps to climate change impacts, such as through the conservation of predator populations^87,94 and thinning of dense kelp canopies to increase water flow and decrease temperatures⁹⁰. Adaptive, ecosystem-based management of marine resources, including kelp, has been advocated for in BC by Indigenous, federal, and regional marine plans²¹ and the new Coastal Marine Strategy⁵⁹, but has not yet been fully operationalized since legal, policy, and governance reforms are a necessary and time-intensive foundation for this management approach. To progress towards implementation, wild kelp monitoring efforts should be expanded, both to detect early-warning signals of climate perturbations³⁸ and ecological tipping points associated with kelp mariculture activities. In neighboring Washington State, this expansion has been achieved through legislating kelp conservation planning (RCW 79.135.440), which has helped mobilize resources to monitoring programs. To increase adaptive potential and reduce risk within the kelp mariculture industry, provincial regulators should create specific licensing avenues for small-scale harvest and experimental cultivation to pilot growing techniques, monitor ecological effects, and test growing conditions at new sites prior to scaling production, as is currently allowed in Maine⁷² and elsewhere. These measures, combined with continued place-based research in collaboration with kelp mariculture practitioners, may allow regulators to formulate climate-adaptive harvest practices and cultivation policies, increasing the ecological and economic resilience of kelp mariculture and de-risking industry investment.

Resources

These proposed interventions only become practically possible through additional funding and capacity building for industry, management, and governance institutions. Substantial funding for businesses and communities is needed to defray the initial infrastructure costs of mariculture, build accessible kelp nursery and processing facilities, stimulate innovation, and develop profitable domestic markets⁶⁷. In BC, such opportunities are particularly needed for Indigenous Nations to reduce barriers to industry entry and ensure Nations have the requisite resources and staff for stewarding wild kelps and associated species within their territories. Small grants are available for supporting Indigenous food sovereignty initiatives in BC (New Relationship Trust; https://newrelationshiptrust.ca/), but scaling the industry will require additional funding supports. In BC and elsewhere within Canada, project finance for permanence (PFPs) models (https://coastfunds.ca/news/indigenous-led-pfps-global-impact/) and Conservation Impact Bonds⁹⁵ that combine government and private funding are being used to simultaneously fuel Indigenous economies and stewardship efforts. These arrangements, along with benefit-sharing agreements for companies operating in Indigenous territories, could assist with developing Indigenous-led kelp industries and funding community-based kelp monitoring and adaptive management efforts in BC.

Conclusions

As we grapple with the challenge of developing sustainable ocean economies amid a climate crisis, systems thinking offers a helpful lens for revealing solutions. Here, we find that across kelp mariculture contexts and spatial scales on Canada’s Pacific coast, provincial and Indigenous governance institutions and their interrelationships through co-governance processes represent key arenas for resolving tensions between conflicting values and relieving the foreseeable “squeeze” of industry development and climate change. We offer a utopic vision of place-based, regenerative kelp mariculture industries that empower coastal economies while nurturing cultural and ecological integrity. However, key uncertainties remain about the social-ecological impacts of scaling up kelp mariculture in a warming ocean. To navigate towards resilience and, in colonial contexts, to uphold our legal and moral obligations to reconciliation, we need the leadership of coastal communities within kelp decision, management, and industry spaces to amplify local priorities and knowledge while enriching and diversifying place-based economies.

Author contributions

A.K.S. conceived of this work and its approach. All authors contributed ideas throughout. A.V.H administered the project, created figures—supported by S.B.G., A.E.A., C.M.A., A.S.W., and A.K.S.—and wrote the initial manuscript draft. A.V.H. and A.K.S. led manuscript revisions, supported by S.B.G., A.E.A., C.M.A., K.A.P., D.R.P., A.S.W., and A.C.M. A.K.S. and A.S.W. acquired funding for this work.

Data availability

No datasets were generated or analysed during the current study.

Competing interests

The authors declare the following competing interests: D.R.P. is the CEO of Ocean Regenerative, a mariculture company based in Vancouver, Canada; A.S.W. serves on the advisory board for Ocean Regenerative in a non-remunerated capacity and was the founding director of Willow Grove Foundation, a funder of this work.