The good news: Making a successful comeback

: The good news: Making a successful comeback

> The return of schools of bluefin tuna in the Pacific, the recovery of the fin whale population in the Southern Ocean: the many minor successes achieved in marine and species conservation show that the recovery of marine life is possible. It will take time, however, as well as appropriate conservation action, close-knit scientific monitoring networks and a rethinking of how we plan to use the ocean in future. Ultimately the effort will pay off – for a species-rich, well-functioning ocean that provides us with much of what we need for a secure and liveable future.

: Fin whales, sea turtles and other returnees
It must have been a breath-taking sight: on 20 March 2019, a group of marine biologists on board a research vessel in Antarctica sighted not five or ten but some 150 southern fin whales (Balaenoptera physalus quoyi) hunting for food off Elephant Island. Their mouths gaping wide, the rorquals dived and surfaced again and again, the jets from their blowholes forming a wall of dancing fountains on the surface of the sea.
Never before had the researchers seen so many southern fin whales congregating at a single site. For too long, the population of these ocean giants – a subspecies of fin whale that can reach an average length of up to 22 metres – was far too small for that. During the era of commercial whaling, stocks had been depleted, the whales hunted almost to extinction. Between 1904 and 1976 alone, whalers slaughtered more than 700,000 fin whales in the Southern Ocean – mainly in the waters around the northern Antarctic Peninsula, where krill and other prey are in plentiful supply. Fin whales have gathered at these feeding grounds since time immemorial.

6.1 > In the waters off Antarctica’s Elephant Island with their abundance of krill, southern fin whales now gather again in their hundreds to feed together.

: In the two decades after commercial whaling ended, however, observers from the International Whaling Commission (IWC) only sighted southern fin whales in this area in isolated cases. It seemed that the rorquals had vanished from their traditional feeding grounds. It took almost 40 years for the whale population to recover to such an extent that the fin whales were able to return to their traditional feeding grounds in their hundreds again.
The example of the southern fin whales proves that even depleted populations can recover if the causes of their decline are eliminated. And there have been reports of similar successes elsewhere in the past two decades: of humpback whales off the east coast of Australia, of sea otter populations in the Canadian province of British Columbia, of leatherback sea turtles nesting in the Virgin Islands, and of coastal areas where degraded or vanished mangrove forests, salt marshes, kelp forests or seagrass beds have been successfully re-established or replanted at their original sites.

6.2 > Am 2. On 2 December 1946, government representatives from 42 nations met in Washington D.C. in the USA to sign the International Convention for the Regulation of Whaling. Since then, a further 46 countries have signed this international treaty.

: The key pillars of successful marine biodiversity conservation
Experts have analysed many of these individual cases to determine which conditions must be put in place in order for heavily overexploited marine biocoenoses to recover. They found, firstly, that species and habitat loss can be halted only if all the causal stressors – not just one – are eliminated or substantially mitigated. This in turn requires holistic solutions that ultimately aim to fully satisfy all the basic needs of the marine organisms once more. These basic needs include clean water, adequate nutrition and an intact and protected habitat in which species can reproduce and raise their young.Secondly, successful biodiversity conservation requires the help and support of a multitude of stakeholders at various levels. It is therefore more likely to involve coordinated action than one-off initiatives. The analysis also showed that restoring heavily degraded habitats or depleted populations is a more promising approach than attempting to re-establish species and ecosystems that have vanished completely.
Factors which have contributed to successful marine biodiversity conservation in recent decades include measures such as banning or strictly regulating the hunting of marine organisms, various sustainable fisheries management strategies, and measures to reduce marine pollution and protect and restore significant coastal and marine ecosystems.

: Regulating the hunting of marine organisms
The population of southern fin whales was able to recover because in 1982, the parties to the International Convention for the Regulation of Whaling (ICRW) voted by a majority to impose a moratorium on the hunting of great whales. The moratorium came into force in 1986 and soon spelled the end for commercial whaling. Nowadays, the International Whaling Commission (IWC) – the ICRW’s governing body – keeps a precise record of the trajectories of various whale populations. It also collects and evaluates information about current risk factors such as underwater noise, ship strikes (collisions), marine pollution, diseases, entanglement in fishing lines, traps or nets, and the impacts of climate change.

6.3 > The International Whaling Commission’s Scientific Committee monitors the trajectory of individual whale populations using computer modelling. The results show that the number of gray whales in the Eastern North Pacific is slowly decreasing, while the vaquita is in immediate danger of extinction.

: Strict international rules also apply to the trade in captured marine organisms; these rules are set out in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (Washington Convention – CITES), which entered into force on 1 July 1975. Its purpose is to ensure that international trade in specimens of wild flora and fauna does not endanger the species’ survival. To that end, CITES monitors international trade in wild flora and fauna on one of three species lists in the Appendices to the Convention. Traders wishing to import or export specimens of these species must apply for a CITES permit. A permit may be refused, depending on which of the three protection categories applies to the species concerned.
Also important for the survival of threatened marine species are measures that mitigate major sources of risk. Such measures can include new-style fishing nets with built-in escape hatches for sea turtles (bycatch), a speed limit for boats and ships crossing whale migration routes (collision risk), or artificial bubble curtains that reduce infrasound from marine construction or piling works (underwater noise).
The corresponding regulations and standards are generally adopted at the national level. One of the best-known rafts of legislation is the USA’s Marine Mammal Protection Act (MMPA), enacted in 1972, which aims to protect marine mammal species from localized extinction. The European Union’s Habitats Directive is broader in scope. In force since 1992, it requires EU member states to maintain and restore natural habitats and wild flora and fauna by establishing a coherent network of special areas of conservation on land and at sea.

6.4 > To maintain native populations of the hawksbill sea turtle and green sea turtle, the Royal Thai Navy operates sea turtle nurseries around the country. The turtles that are bred here are regularly released into the wild.: Sustainable fisheries management
With the aid of various measures to regulate fishing, it has been possible to rebuild depleted local and regional fish stocks in some regions of the world. Limited fishing quotas and fishing periods, fishing bans in selected zones, regulations on permitted fishing gear, and agreements on the integrated and sustainable management of marine regions and their resources have proved particularly effective in this context.
It was sustainable fisheries management that laid the foundation for the return of bluefin tuna (Thunnus orientalis) in the northern Pacific Ocean, for example. As a result of heavy overfishing in the 1990s and 2000s, stocks of this coveted predatory fish had declined to such an extent that the few remaining specimens amounted to just two per cent of its potential unfished level in 2009 to 2012. In 2011, the fishing nations concerned responded to this dramatic decline by reducing their catch of both juvenile and larger bluefin and henceforth coordinating their approach. As a result, more juveniles reached sexual maturity and were able to reproduce. Stocks experienced a remarkable recovery: by summer 2024, the population had rebounded to around 20 per cent of the potential unfished stock – ten years earlier than originally projected.

6.5 > Selected marine species that appear on the three species lists in the Appendices to the Washington Convention (CITES).

: Measures to reduce marine pollution
Various national provisions aimed at improving water quality in rivers and inshore waters have helped to reduce pollutant and nutrient inputs to coastal waters, mitigating the risk of unwanted algal blooms and hence the formation of oxygen-depleted zones. International agreements such as the Stockholm Convention on Persistent Organic Pollutants (POPs) have resulted in the banning or strict regulation of the use of certain chemicals that accumulate in the environment, so less of these pollutants enter the sea.
The International Convention for the Prevention of Pollution from Ships (MARPOL) has also had an effect. The Convention and a protocol thereto entered into force on 2 October 1983. It includes regulations aimed at preventing and minimizing pollution from ships – both accidental pollution and that from routine operations. The 1992 amendments to Annex I require shipping companies and shipbuilders, from 1996, to construct oil tankers with double hulls in order to increase safety in the transportation of crude oil and petroleum products by ship. If the outer hull is ruptured in a collision or stranding, the second hull is there to prevent oil spillage. The MARPOL Convention also includes specific provisions on the construction, equipment and operation of chemical tankers.

6.6 > How quickly do marine species recover from harmful impacts or events? That depends on their reproductive cycle. Oysters reproduce rapidly, but it takes 20 to 40 years for a few individual seals (pinnipeds) to develop into a colony.

: In addition to technical provisions and legislation aimed at improving water quality, projects to restore marine habitats that naturally filter particles, nutrients and pathogens out of water bodies have also proved their worth. These are, specifically, mussel beds, seagrass meadows, salt marshes and mangrove forests.
In the extended harbour area of the US metropolis of New York City, for example, an environmental organization is attempting to reintroduce American oyster (Crassostrea virginica) at 18 sites. At one time, the natural oyster reefs here covered almost 900 square kilometres – 100 square kilometres more than the area of the city. The oyster reefs vanished in the 1920s, however, killed off by overfishing over the course of more than a century and by severe pollution of the rivers discharging into the sea.
Although rainwater and road runoff still enter the harbour via the city’s drainage system, the situation has been gradually improving over the last 20 years or so. Oysters can now survive along the New York shoreline again, and if the reintroduction is successful, water quality is likely to further improve. As suspension feeders, the American oyster removes nutrients from the water column that would otherwise drive algal growth and the formation of oxygen-depleted zones. The oysters filter surplus nutrient-rich particles out of the water, as well as microalgae that have grown as a result of eutrophication. Targeted oyster cultivation is thus seen as an innovative and cost-effective measure for coastal and water resources management.

6.7 > Volunteers from a marine conservation organization, the Billion Oyster Project, start work on restoring an oyster reef in the harbour of the US city of New York. Healthy oyster reefs filter water, provide food and habitat for hundreds of species and protect the shoreline from storm and flood damage.

: Meanwhile, on dry land, the government of the Australian state of Queensland was seeking a solution to the high sediment and nutrient inputs to the Great Barrier Reef, caused mainly by overgrazing on a large cattle station in the northern part of the state. In areas where overgrazing had exposed the soil, runoff of sand and other particulate matter frequently occurred during rainfall. These particles were then washed down the Normanby River into the northern coastal sea, reducing its water quality, with particularly adverse impacts on seagrass beds and the numerous corals in this marine region. To overcome the problem, the state of Queensland purchased the cattle station in May 2016. It phased out livestock farming, transformed the grazing land into a nature refuge and implemented various on-site measures to control erosion. In addition, since 2017, the government has been pursuing a specially designed programme to improve water quality on the Great Barrier Reef and, among other things, provides funding for training and research on minimizing erosion in farming.

6.8 > In 2016, the government of the Australian state of Queensland purchased large tracts of land within the Normanby River catchment in order to halt overgrazing. The conservation measures aim to reduce the sand and other sediment inputs from the river that cause turbidity of the water masses on the Great Barrier Reef.

6.8 > In 2016, the government of the Australian state of Queensland purchased large tracts of land within the Normanby River catchment in order to halt overgrazing. The conservation measures aim to reduce the sand and other sediment inputs from the river that cause turbidity of the water masses on the Great Barrier Reef.: Conservation and restoration of significant habitats
Over the past 30 years, countless initiatives have been launched to conserve and restore marine habitats around the world. They focus particularly on coastal ecosystems such as mangrove and kelp forests, seagrass beds and salt marshes, and mussel and tropical coral reefs. The most successful were conservation and restoration projects that were planned and implemented jointly by experts and local communities, covered as large an area as possible and whose funding was secure. These projects not only take scientific and indigenous knowledge into account; they also factor in that coastal communities need to harvest a certain amount of fish, shellfish, timber and other resources from the ecosystems in order to generate income. What is needed, therefore, is an adequate knowledge base, mutual agreements, and powerful incentives for local communities to act prudently and only extract as much food and material as the ecosystems can spare.
There is no “one-size-fits-all” solution for restoring marine habitats. In the past, many attempts to replant mangrove forests failed, either because they were planted in the wrong place or the wrong species were used. The experts therefore advise against actions of an ad hoc nature. Instead, each restoration measure should be well thought-out and planned and implemented in line with local conditions and needs.
An impressive success rate of 88 per cent has been chalked up by projects that have attempted, over the last 50 years, to free islands from the scourge of invasive rats. Wherever these efforts have been successful, not only have seabird colonies recovered: numbers of lizards and insects have also increased. Eradication campaigns of this kind have been carried out on the Galápagos island of Floreana, for example, as well as on South Georgia in the South Atlantic, one of the most important breeding sites for king and macaroni penguins.

6.9 > Seabirds such as the grey-headed albatross (Thalassarche chrysostoma) have benefited from the systematic eradication of rats from the island of South Georgia in the South Atlantic.

: How long do marine organisms and habitats take to recover?
The more extensive the human-induced damage sustained by a marine ecosystem or population of marine organisms, the longer it will take for them to fully recover. In numerous cases, the extent of the degradation or population decline is severe.
Seabird counts in the United Kingdom and Ireland have revealed that populations of eleven of 21 native seabird species – in other words, over half – have declined by more than ten per cent since 2002. The ornithologists recorded population increases for just five species. The number of threatened warm-water coral species increased from 33 per cent to some 44 per cent between 2008 and 2024. This means that of the 892 known reef-building tropical coral species, at least 340 species now fall into one of the three IUCN Red List categories of threat. Among these, 56 species are “vulnerable”, 251 are “endangered” and 33 are “critically endangered”. An important point for any reader wishing to check the figures here: coral species for which the experts had deficient observation data were also classed as “vulnerable”.

6.10 > Staghorn corals (Acropora) are keystone marine species: with their many tiny “antlers”, they provide habitat and hiding places for other small marine organisms. Tropical coral reefs host an estimated 25 per cent of all marine species.

: How quickly can populations start increasing again? That partly depends on the speed at which the species reproduce. This then raises other questions: how many young are born in each reproductive cycle? How many of them ever reach sexual maturity? And how many older members of the population die within the same period? The great whales, for example, reach sexual maturity later than seals. In part, this explains why fin whales, blue whales and related species need more than 100 years of intensive protection to rebuild healthy populations after the calamitous whaling era, whereas elephant seals and fur seals, which were also hunted intensively, were forming large colonies again after just a few decades.
Sea turtles also take up to 100 years to recover from population decline. However, experience has shown that some populations are capable of far more rapid growth. In Hawaii, for example, the number of green sea turtles (Chelonia mydas) – strictly protected since 1974 – had increased sixfold by 2016. Two years after this reported success, however, a hurricane hit the turtles’ main nesting site, and wind and waves washed away large areas of the low-lying atoll. Will the turtles recover from this setback? Only time will tell.

Population recovery
Experts identify various stages of recovery, depending on population growth. A partial recovery means that population figures increase by ten to 50 per cent. A rise of 50 to 90 per cent is described as a substantial recovery, while a full recovery requires population growth of more than 90 per cent.: Planning for present and future impacts of climate change
The example of the green sea turtles illustrates the extent to which increasingly frequent weather extremes and other climate change impacts are jeopardizing the recovery of marine species and impeding effective conservation measures. The scale of these extremes and impacts also explains why the increase in great whale populations in the Southern Ocean does not, by any means, imply that their survival is guaranteed. The future of these recovering populations is uncertain, experts at the Scientific Committee on Antarctic Research note; they too identify climate-related changes in the ecosystem of the Southern Ocean as the cause.
In regional and global research networks and programmes, scientists from various disciplines are monitor-ing climate change and its impacts on the marine environment and forecasting the changes that can be expected in the next decades and centuries, depending on how quick-ly the Earth heats up.
In the international Fisheries and Marine Ecosystem Model Intercomparison Project (FishMIP), climate and ecosystem modelling experts combine the results of nine global ecosystem models with climate models that project changes in variables such as greenhouse gas emissions, water temperature, biomass production and the strength of the major ocean currents.
Among other things, they have found that by 2050, many of the world’s marine regions could see their fish biomass drop by more than ten per cent if humankind continues to produce such high greenhouse gas emissions and climate change continues apace. By 2100, the decline could even reach 30 per cent or more if there is no reduction of emissions and global temperatures rise by three to four degrees Celsius above pre-industrial levels.
Detailed projections such as these are urgently needed so that fisheries and other planned uses of the ocean can be adapted to the anticipated changes in environmental conditions. Identifying areas of the sea where marine heatwaves will occur more frequently in future or where ocean acidification and sea levels will rise dramatically also enables experts to decide where investment in costly restoration of salt marshes and other coastal ecosystems is worthwhile – and where projects of this kind would be very likely to fail due to climate change.

6.11 > During the summer drought in 2018, the surface of the German Wadden Sea’s tidal flats dried out completely in some places. These arid conditions put ground-dwelling organisms under extreme stress.

: Restoring marine flora and fauna – some guidance
Due to the resilience of many species and the successes achieved in restoring marine ecosystems, researchers are hopeful that marine flora and fauna can be rebuilt if simultaneous efforts to limit global warming and mitigate the impacts of climate change are successful. The experts recommend that every effort be made, above all, to increase the abundance of important marine habitats and keystone species and halt the degradation of biocoenoses on the seabed (bottom trawling, filling, laying of pipelines, cables, etc.).
A defining characteristic of significant habitats is that they serve as a breeding ground, nursery, refuge and food source for many species associated with the ocean. Examples are coral reefs, seagrass beds, mangrove forests, salt marshes and kelp forests, as well as many areas of the seabed at various water depths, including on submarine mountains. A keystone species, in this context, means a species that has a disproportionately large impact on the environment relative to its abundance and plays a key role in maintaining the functions of marine ecosystems.

6.12 > In order to protect sharks and rays effectively, it is essential to know which regions of the world’s oceans are frequented by these predatory fish. An international team of experts took on the task of identifying and mapping these areas of the sea.

If keystone species vanish from their ecosystem, this can lead to dramatic shifts within the community and radically change ecosystem dynamics. Identifying and preserving keystone species is therefore crucial for ecosystem resilience and stability – on land and in the ocean. Unfortunately, experts do not always agree on a definition of “keystone species” or which species should be described as such. In essence, however, keystone species fall into the following three categories:

Habitat-forming species, also known as ecosystem engineers: Through their growth and distribution, they contribute to the creation of new three-dimensional habitats that can be colonized by other species. This category includes seagrasses, macroalgae, corals, mangroves, salt marshes, reef-building mussels and glass sponges.
Prey species: They generally occur in large schools and serve as a food source for a wide variety of predators. Without Antarctic krill, for example, baleen whales, penguins, fish, seals and other seabirds in the Southern Ocean would starve. Other typical prey species are schooling fish such as herring, anchovy and sardine. In Arctic waters, copepods play a key role in the food web.
Predatory species that have a disproportionately large impact on the structure of their community’s food web: In simple terms, these are predators that keep other species in check and thus maintain a balance within their habitat. They include sea otters, which feed on sea urchins; limpets (Patellidae), which graze on algae on rocky shores; sea stars, which hunt mussels in the intertidal zone; and orcas – predators which patrol Prince William Sound off the west coast of North America, where sea otters are their preferred prey.

: There is, however, also some discussion as to whether keystone species should, perhaps, be defined as a species complex on which the structure, functioning and all the various characteristics of the entire ecosystem depend. This refers to core species within an ecosystem that interact with each other in predator-prey relationships and on whose interaction all the other species are dependent. An example of a species complex is the interplay between microalgae, seagrass, zooplankton, invertebrates, hogfish (Lachnolaimus maximus), snappers and other predatory fish on the Media Luna Reef off the coast of Honduras.
What action needs to be taken to strengthen keystone species and habitats in the ocean? There is a wealth of knowledge and a consensus among experts here.
Firstly, it is essential to preserve the remaining intact marine and coastal areas and protect them from more intensive use. In densely populated coastal areas, this may prove challenging because very few healthy, unaltered biocoenoses still exist. On the remote shores of North and South America, in the Arctic and Antarctic, and in parts of Africa and Australia, however, there are certainly still some intact species-rich marine ecosystems that should only be used sustainably, if at all.
Secondly, all the conservation measures that have already been initiated and are proving effective must be continued and their scope expanded. There is a particularly urgent need for action to combat the contamination of the marine environment by new persistent pollutants such as “forever chemicals” and plastic. Due to the slow recovery of many keystone species and habitats, it may take many decades for the hoped-for successes to be achieved.

Extra Info Scenarios conducive to achieving the best aspirational outcomes towards rebuilding marine life: Thirdly, for all degraded key marine ecosystems, rapid and mutually reinforcing conservation and rebuilding measures must be taken – also to avoid potential tipping points. If these tipping points are crossed, there is a risk of irreversible ecosystem collapse. The packages of measures must aim to protect and restore species and habitats in all their diversity and functionality, limit all forms of use to a sustainable level, reduce all forms of marine and coastal pollution or prevent them entirely, and effectively mitigate climate change and its numerous impacts.
In order to achieve these objectives, responsible, integrated action by policymakers, business, the scientific community and civil society is required at all levels. With consistent, knowledge-based marine management, the researchers say, humankind may yet succeed in strengthening marine biodiversity on a lasting basis so that by 2050, many significant marine ecosystems are able to recover, with increased resilience, and life in the ocean can once again provide the multitude of services that are essential for human survival.

6.14 > A pod of humpback whales gorges on Californian anchovy (Engraulis mordax) in Monterey Bay off the coast of the US state of California. Once a heavily polluted stretch of coastal water, the Bay is now known as the “Serengeti of the Sea”.: The need for dynamic marine management
What might sustainable, biodiversity-boosting marine management look like? There is no universally valid answer to this question. The packages of measures adopted must be tailored to local conditions – while also aligning with regional, national and international framework strategies. In view of the growing frequency of weather extremes such as storms and marine heatwaves, and with climate-related shifts in community composition, dynamic forms of marine management that facilitate prompt and far-sighted action are required.
If, for example, a coastal area is affected by a prolonged heatwave that inhibits the reproduction of native mussel beds or fish populations in full or in part, it would be sensible to cancel the planned mussel harvest or fishing season in order to prevent any further weakening of the biocoenosis. Similar decisions may be required if ocean warming causes herring or other schooling fish to spawn prematurely, before the blooming of the microalgae that serve as their larvae’s food supply. Conditions such as these can result in the loss of an entire year’s offspring – with dramatic impacts on the population as a whole.
Timely and, above all, science-based action in such scenarios is conditional upon three sets of measures, however: firstly, the environmental parameters and ecosystems in sea areas with human use must be closely monitored and all changes documented. Secondly, technical staff are required to evaluate the data and produce recommendations for action. In a third step, these recommendations must then be implemented, with monitoring of compliance – which requires other processes and rules and is, in turn, conditional upon all participants and stakeholders showing the necessary insightfulness.

: Dividing the sea into zones
If marine life is to recover while human claims on the ocean simultaneously increase, the division of the ocean into separate zones is likely to be unavoidable. On the one hand, well-functioning and interconnected marine conservation areas are needed in which marine biocoenoses are genuinely protected from direct human impacts. On the other, some marine regions will have to be intensively used. Even here, however, marine biodiversity can benefit if the various forms of use are coordinated and their environmental impacts are balanced out. Monterey Bay on the Pacific coast of the US state of California shows what this sustainable use of the ocean might look like.
Around 90 years ago, the sea here was a stinking cesspool. Wastewater was discharged untreated into the ocean. The many fish canning factories dumped their waste in the Pacific. Sea otters, once native to the Bay, were now close to extinction, and the kelp forests had largely vanished. When the sardine fishery collapsed from the latter half of the 1940s onwards due to massive overfishing, and the canning factories were forced to close, it seemed that the fate of the local marine ecosystems and, with them, the region as a whole was sealed.

6.15 > Sunlight pierces the interior of a smokehouse belonging to the Nisga’a, an indigenous people on Canada’s Pacific coast. In spring, the coastal dwellers catch and process eulachon (Thaleichthys pacificus), which migrate in large schools from the sea into the Nass River in order to spawn there.

: A change for the better began with a shift in mindset on the part of the local community. In October 1984, a new marine aquarium opened in Monterey; since then, it has kept locals and visitors informed about the importance of local marine flora and fauna. New legislation was adopted to regulate fishing, and in September 1992, the coastal waters from San Francisco in the north to San Luis Obispo in the south were designated a protected area, where the discharging of wastewater, drilling for oil and gas, marine mining and the hunting of marine mammals are prohibited. Marine research institutes were established in the Bay area.
Nowadays, fisheries experts from Monterey Bay Aquarium collaborate with local fishermen: together, they inform the public which species of fish should be eaten at which time of the year, where fish and shellfish can be purchased from local and sustainable fisheries, and which local restaurants have them on the menu.
All these conservation measures are having an effect. Not only have the fish and otter populations and kelp stocks recovered over time. Monterey Bay has now been dubbed the Serengeti of the Sea: alongside blue, gray and humpback whales, the Bay now hosts at least 525 species of fish, more than 180 coastal and seabird species, four species of sea turtle, around 450 different species of algae, and numerous and diverse invertebrates. This abundance of species, along with California’s beautiful beaches, attracts holiday-makers and sports enthusiasts from all over the world to the Pacific coast. Ocean tourism is now a major source of income for local people. The balance between marine conservation and use will only function, however, as long as the impacts of climate change on life in and near the ocean can be kept to a minimum. Sadly, it does not augur well at present.

: Utilizing coastal indigenous peoples’ traditional knowledge
In the search for solutions that enable the sea to be used in ways which promote biodiversity, researchers are increasingly exploring the traditional knowledge of coastal indigenous peoples, integrating these communities’ expertise into research projects and involving them in decision-making processes. Many indigenous peoples have made sparing use of the ocean’s resources since time immemorial and are privy to powerful lore and rules that are not written down in any textbook or academic paper.
This new co-creation of ocean knowledge does not mean, however, that indigenous communities do not also pursue their own commercial interests in their management of marine resources. On Canada’s northeast coast, for example, the indigenous-led regional government and Canada’s national parks administration (Parks Canada) agreed to adjust the boundary of a newly planned marine conservation area so that local fishing families could continue to fish for mussels, shrimp and flatfish with trawl nets in their traditional fishing grounds. In the rest of the Inuit-led marine conservation area, this highly destructive fishing practice will be banned in future.

: From individual to collective responsibility
Successful nature and marine conservation often starts with a growing awareness on the part of a few individuals, followed by their commitment to engage actively for the conservation of species and habitats. They may be local environmental activists who protect sea turtle beaches and eggs or protest against destructive practices. However, they may also be researchers who voice their concerns on the basis of their monitoring or research findings, or persons in leadership roles who have their own conception of what constitutes sustainable use of the marine environment and are willing to work towards, and implement, the necessary policy, legislative and management reforms.
The transformation that is required may be initiated by grassroots projects whose agenda or actions then have an impact on the political level (bottom-up), or conversely, by the adoption of reforms at the political level, whose provisions must then be implemented nationally, regionally and locally (top-down). A current example of a top-down process is the European Union’s Marine Strategy Framework Directive, adopted in 2008. It requires coastal states in the EU to develop a national marine strategy to assist in achieving or maintaining good environmental status in marine waters. The national strategies and associated programmes of measures are reviewed and updated every six years.

: A worthwhile investment
Protecting marine habitats and biodiversity and restoring them wherever they have been degraded requires collective action and adequate financial resources. It is estimated that the international community will need to invest at least ten to 20 billion US dollars annually in order to extend existing conservation measures to cover around half the world’s ocean. Additional resources would be required to fund the necessary restoration measures. The financial return on this investment would be substantial, however, amounting to roughly ten US dollars for every dollar invested. More than a million new jobs would be created at the same time.
Investing in marine conservation pays off, as projects in Chile and Australia show. In both countries, the desig-nation and implementation of marine protected areas have led to an increase in biological diversity, greater abundance of fish for human consumption, higher incomes for local communities and – in Australia’s case – higher revenues from tourism. Worldwide, wildlife tourism – safaris, whale-watching and other wilderness experiences on land and at sea – contributed 120 billion US dollars to global GDP in 2018. Around 21.8 million people were employed in this sector over the same period.
Healthy marine ecosystems could offer additional economic benefits for fisheries and aquaculture facility operators, as well as for the insurance industry. With sus-tainable fishing, breeding and farming methods, the former can potentially achieve a sixfold increase in the amount of food harvested from the ocean compared with the present level – with a smaller environmental footprint. Meanwhile, the insurance industry could save many billions of dollars annually if intact coastal ecosys-tems were in place to lessen the impact of storm surges and thus limit the damage they cause.

Extra Info A third conservation goal: Genetic diversity for better adaptation prospects

A global partnership

Restoring marine ecosystems, some of which are heavily degraded, requires a global multi-stakeholder partnership. These diverse stakeholders particularly include governments, businesses, artisanal fishermen and others whose livelihoods are directly dependent on the sea, as well as civil society. They must all reach agreement on a knowledge-based action plan that comprises the following elements:

clear guidelines for equitable marine conservation policies and related decision-making processes (including provision for local community participation and free access to all information of relevance to the process),
adequate financial resources,
coordinated agendas for marine research and for education providers,
clearly defined objectives and measurable performance indicators, and
a business plan showing how the investment will pay off in monetary terms.

In addition, proven experts are required to provide the knowledge and technologies needed to rebuild marine biodiversity and habitats. And lastly, adequate human resources must also be available to deliver the agendas.
Our fundamental conception of how we use the seas must also change. While this previously focused primarily on individual benefit or corporate profits, a new direction of travel is needed for the future. Human communities should utilize the ocean solely in ways which strengthen marine ecosystems and, in an ideal scenario, create other additional benefits – namely, increasing everyone’s prosperity, or motivating decision-makers to make further efforts to rebuild marine life. The successes achieved in species conservation to date reinforce the message that healthy and intact marine habitats are an entirely realistic goal.