Marine biodiversity

Marine biodiversity is vital to life in our ocean. We can all play a part in protecting marine biodiversity.

What is marine biodiversity?

Marine biodiversity is the variety of life in our ocean. It includes all animals, plants and microorganisms living in our ocean, from barnacles to whales to coral reefs. The term is also used to describe the abundance of species living in an area.

Some places have such a large variety of different and rare species, they are referred to as biological “hotspots”. These are areas of high biodiversity that generally support important biological processes such as spawning, nurseries or feeding areas. Some also have species not found anywhere else in the world.

Examples of marine biodiversity hotspots include the Benguela Current Large Marine Ecosystem off the coast of Namibia and the Central Indo-Pacific region, which includes the coral reefs of Southeast Asia and Australia and contains the most species of any ocean area.

The importance of marine biodiversity

Marine biodiversity allows nature in our ocean to be productive, resilient and adaptable to environmental changes. Marine biodiversity can prevent one species’ extinction from causing wider negative impacts on a marine ecosystem.

We say an ecological system is resilient if it keeps functioning even when the population of a species declines, or a species becomes extinct. A functioning ecosystem means the natural processes are working effectively, including those providing goods and services to humans, such as storing carbon or filtering water.

Each species in the ocean has a particular role to play, whether that is marine worms converting organic material into carbon dioxide for marine plants to photosynthesise or sharks controlling prey populations. Some species play similar roles in an ecosystem, so if one species becomes extinct, another will be able to carry out the same function or ‘service’.

Risks to marine biodiversity

Some species are unique in function and their extinction would represent the loss of millions of years of evolution. For example, the largetooth sawfish is the most evolutionarily distinct and globally endangered ray fish in the world, targeted by the wildlife trade and vulnerable to bycatch.

The more biodiversity becomes depleted, the less nature can provide the food, economic and cultural benefits it currently provides to humanity. But even if humans disappeared tomorrow, biodiversity would still remain vital to the planet’s success. Manatees, sharks or sea squirts have the right to exist and thrive for their own sake.

Major risks to marine biodiversity include:

  • Overfishing
  • Bycatch
  • Climate change
  • Pollution
  • Invasive species
  • Other human-related impacts

Solutions to protect marine biodiversity

  1. Choose sustainable seafood: look for the blue fish tick on seafood products
  2. Use less plastic: be mindful about single-use plastic 
  3. Recycle: from schemes like RecycleSmart to local council pick-ups
  4. Reduce your carbon footprint: from cutting down on red meat to switching to renewable electricity
  5. Pick up litter at the beach: just a little each time can make a difference
  6. Support sustainable fishing practices: you can donate to the MSC and support our mission to end overfishing 
  7. Promote ocean literacy: encourage your local school to use our free ocean-themed learning resources

MSC certified sustainable seafood

The effects of fishing on marine biodiversity

Overfishing can seriously impact marine biodiversity. Around 34.4% of the world’s fish stocks are currently overfished, and if this continues there will be less fish in the ocean for future generations as well as less biodiversity.

Overfishing not only impacts the fish that are targeted for harvesting but also other marine life that interacts with fishing vessels. Oceanic shark and ray species have declined by 71% since the 1970s, with overfishing the primary cause of the decline.

Bycatch is one of the leading threats to marine biodiversity. It is estimated that 9.1 million tonnes (around 10% of annual catches) are discarded by marine commercial fisheries each year.

Minimising the impact of fishing on marine biodiversity

A key component of the MSC Fisheries Standard is assessing the fishery’s impact on the wider biodiversity and ecosystem. Many fisheries that enter the MSC program are given conditions of certification, which are a series of improvement goals they must meet to keep their certificate.

From 2018 to 2021, these conditions led to a total of 372 improvements. This includes 66 improvements benefitting ecosystems and habitats and 134 improvements benefitting endangered, threatened and protected species and reducing bycatch among others.

The Australian Eastern Tuna and Billfish Fishery introduced circle hooks, de-hookers and line cutters to help mitigate turtle bycatch as well as implementing electronic monitoring on all its vessels. In Greenland, scientists at ZSL (Zoological Society of London) are helping map the seabed floor to help fisheries avoid vulnerable marine ecosystems. The work has identified over 230 groups of organisms from underwater images and has subsequently helped close all but two conditions relating to the wider ecosystem. In Cornwall, hake fishers have used pingers – acoustic devices – to deter marine mammals from becoming entangled in gillnets, reducing harbour porpoise bycatch by 80%.

The MSC Fisheries Standard is also reviewed and updated regularly, in line with global best practices, policies and science. Our analysis shows that the average scores of fisheries significantly improve as they stay in the program. This shows that fisheries that remain in the MSC program actively improve their practices to reduce their impact on biodiversity.

Supporting global biodiversity conventions with ocean data 

The MSC program also contributes to the work of United Nations (UN) bodies such as the Food and Agriculture Organization (FAO) in several ways. Data from the MSC is used by the UN Environment Programme and other intergovernmental organisations to track progress towards international goals to end overfishing and protect biodiversity. In 2020, the MSC’s contribution to sustainable fishing and progress towards biodiversity goals was acknowledged by the UN

The MSC program incentivises sustainable fishing practices that ensure target fish stocks are healthy, fisheries are well managed and the impacts on marine biodiversity are actively minimised.

Ecosystems and Improvements

In 2020, 100 improvements were made by fisheries as part of being certified to the Marine Stewardship Council’s sustainability standard – with over half of those related to endangered, threatened and protected species.

Unsustainable fishing practices are a serious threat to the biodiversity and productivity of our oceans. Yet we know that with proper management, depleted stocks and damaged ecosystems can recover.

Dr Rohan Currey, MSC Chief Science & Standards Officer
Sustainable seafood guide

Sustainable seafood guide

Where to buy, what to look for and the questions to ask.

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