Ocean News

Putting critical sites for sharks on the map

By Isla Hodgson, 12th April 2022

Sharks, rays and chimaeras – collectively known as Chondrichthyes, the cartilaginous fish species – are one of the most threatened animal groups in the world. Of approximately 1,250 named species, at least 37% are estimated to be threatened with extinction. Dramatic declines in the global abundance of many species have occurred in the past 50 years as a direct result of increasing exploitation and human pressure, compounded by their life-history traits. Although these vary between species, generally sharks, rays and chimaeras are long-lived, take a long time to reach maturity, are slow to reproduce and, when they do, produce few young. These characteristics make them extremely vulnerable to overfishing and other human-induced impacts, like climate change and habitat degradation. It is crucial that we find new and effective ways to protect these species before it’s too late.

St Joseph Atoll, Seychelles, from above. Photo by Michael Scholl | © Save Our Seas foundation

An important step towards the global conservation of sharks, rays and chimaeras (for ease, we’ll refer to them as ‘sharks’ from now on!) is the identification of areas that are critical to the survival of these species. Sharks rely on specific habitats and locations for various reasons. Some species may only be found in one habitat or part of the world, like the pyjama shark that is endemic to the kelp forests of South Africa. Others may depend on certain habitats to support an individual life stage – like mangroves, which serve as nursery grounds for the juveniles of species such as blacktip, lemon and hammerhead sharks. There are locations around the world where several shark species aggregate at certain times of year to take advantage of seasonal abundances of prey or to mate. Or there are sites that act as strongholds for Critically Endangered species. Knowing where these areas are – and what threats overlap them – is essential to informing future conservation strategies and ensuring that they are targeted, systematic and effective.

Scientific research has pinpointed hundreds of these areas in the past few years. But, until recently, this information has stayed within academic circles or individual case studies. What is needed is for all the pieces to be put together so as to create a global picture of critical areas for shark, ray and chimaera conservation – and for this information to be made accessible and available so that governments, managers and other stakeholders can make informed decisions and put adequate protective measures in place. This is exactly what the Important Shark and Ray Areas (ISRA) project, led by the IUCN SSC Shark Specialist Group, aims to do. Its team is working closely with the IUCN Ocean Team and the IUCN Marine Mammal Protected Areas Taskforce to develop ISRA selection and review criteria, a critical component of the project that is being funded by the Save Our Seas Foundation (SOSF).

A juvenile lemon shark in a mangrove forest, Bimini, The Bahamas. Photo by Shin Arunrugstichai | © Save Our Seas Foundation

What are Important Shark and Ray Areas (ISRAs)?

ISRAs are officially defined as ‘discrete, tri-dimensional portions of habitat, important for one or more shark species, that have the potential to be delineated and managed for conservation’. Let’s break that down. ‘Discrete’ means that they are separate areas and are individually distinct. ‘Tri-dimensional’ sounds like something from outer space but refers to the fact that different shark species are not only found across the world’s oceans, but also at different depths. ISRAs, therefore, need to take a species’ depth range as well as its geographical range into account.

Finally, ISRAs describe the importance of these portions of habitat for shark survival and well-being, highlighting the potential for conservation and protection. This distinguishes them from marine protected areas that are established and where specific regulations have been put in place to control or mitigate negative impacts on marine life. ISRAs are what is known as a ‘spatial tool’; a tool for identifying and prioritising specific areas for conservation, marine spatial planning and restoration. They can help decision-makers and managers decide what actions are appropriate to best protect that area. This advice might include designating it as a marine protected area, but ISRAs are not marine protected areas in themselves.

Mating nurse sharks, The Bahamas. Photo © Shane Gross

Why are ISRAs important?

We’ve already talked about the dire situation sharks and their relatives are in and how identifying and mapping the areas crucial to their survival and well-being are important steps in reversing species’ declines. ISRAs provide a global-scale strategy to achieve this and they create accessible information that can be used to inform management and conservation actions specifically targeted to sharks. Until recently, shark conservation efforts have concentrated mainly on regulating fisheries and trade in a bid to tackle two of the greatest threats to sharks: overfishing and the trade in fins, meat and gill plates. Although some legislation has been monumental – such as the recent ban on the retention of North Atlantic shortfin mako sharks – fisheries and trade management alone is not enough. Equally, marine protected areas have been important in protecting species that spend a lot of time in one area, such as reef sharks, but they are less effective for highly mobile species. ISRAs will ensure that these species are no longer overlooked.

In addition, mapping ISRAs will enable governments to compare their location with information about human activity and could help to reduce harmful interactions, for example where fisheries overlap with ISRAs or where shark migratory routes intersect shipping lanes. This information can be combined with that from other similar initiatives – such as Important Marine Mammal Areas (IMMAs) and Important Bird and Biodiversity Areas (IBAs) – to inform protective measures for groups of species impacted by the same threat, such as bycatch. ISRAs are likely to be important not just for sharks; the protective measures they encompass will undoubtedly benefit other species living within them.

ISRAs will also bring sharks into the conversation regarding global frameworks for wider marine conservation and make sure that they are considered in the decisions made to meet international biodiversity targets. This includes the ’30 by 30’ target outlined by the Convention on Biological Diversity, which aims to protect 30% of the global ocean by 2030. ISRAs will ensure that sharks – as one of the most threatened groups – are a key part of the decision-making when it comes to deciding on future protected areas.

Dr Alec Moore, a shark scientist who has contributed to IUCN Red List Assessments and conservation initiatives for highly threatened elasmobranchs, is the lead author of a recent journal article (alongside SOSF scientific advisor Sarah Fowler) on the desperate need for conservation tools and measures specific to sharks. Speaking about the importance of filling such a stark gap in the tools available for shark protection, he says, ‘The Environmental Impact Assessment process for marine development projects typically draws on well-known sources of information about environmentally sensitive areas, such as marine protected areas, IBAs and, more recently, IMMAs. These are freely available, scientifically robust mapping resources that clearly show why a given area is important, allowing decision-makers to avoid or reduce impacts on the group being considered. There was never anything similar specifically for sharks and rays, yet so many of them have spatially discrete areas that are important. [We are filling this gap by developing] a globally recognised, scientifically robust and freely available resource for decision-makers.’

Critically endangered bowmouth guitarfish, Seychelles. Photo © Byron Dilkes.

How are ISRAs identified?

ISRAs will be decided using a set of scientifically based criteria. These criteria are designed to capture essential aspects of shark ecology and biology and will be aligned as far as possible with those used for IMMAs, IBAs and Key Biodiversity Areas (KBAs,) which have already been tried and tested. Examples of the criteria are:

  • Uniqueness or distinctiveness: does the area support genetically, behaviourally or ecologically unique populations that can’t be found anywhere else?
  • Diversity: does the area support multiple different species or just a single species?
  • Vulnerability: is this area important for the survival and recovery of a declining or threatened species?
  • Distribution and abundance: does this area support a specific population? Do sharks aggregate in this area? Are there a high number of individuals in this one area?
  • Key life cycle areas: is the area essential to support a particular life stage of a species e.g. juveniles, feeding areas, migration routes?

The specific criteria for ISRAs have not yet been decided and they may have to be adapted from the above to make sure they work for all sharks. There are 130 known species of marine mammals but more than 1,200 species of sharks, so it’s likely that changes will need to be made.

As described in a recent study, Galápagos has the worlds largest shark biomass. Photos © Pelayo Salinas.

How are ISRAs being developed?

The ISRA project is currently being implemented by an international team of experts led by the IUCN SSC Shark Specialist Group. The first crucial step is to settle on the selection and review criteria that will be used to identify ISRAs. This is a task currently being completed as a collaboration between the Shark Specialist Group and the IUCN Ocean Team, funded by the SOSF through a grant and led by Lynn Sorrentino. The project, titled ‘Defining Criteria for Important Shark and Ray Areas: Regions, Networks and Intervention Points for Shark, Ray and Chimaera Conservation’, will aim to define the criteria necessary for the establishment, management and monitoring of ISRAs using the best available science and to highlight any gaps in the knowledge base. This information will then be turned into guidance that is accessible for stakeholders, funders and decision-makers to ensure it is used in marine management decisions moving forward.

Another essential step is to divide the world’s oceans and seas into workable ‘regions’. This makes it easier to identify potential ISRAs and cooperate with experts who know a lot about the area and the sharks within it. Once the criteria and regions are decided, the team will host a series of workshops on a region-by-region basis, where experts from that region will work closely together to identify ‘candidate’ ISRAs. This will be no easy task – ISRAs can be in any part of the ocean, from the high seas to the coasts and rivers, from the depths to the shallows. They may even include changeable boundaries like oceanographic fronts! The candidate ISRAs will then be reviewed by an independent panel and new ISRAs will be officially classified. ISRAs can then be put on the map and used by decision-makers for future designation as marine protected areas.

Oceanic manta ray, Mexico. Photo © Matthew During

It will be a long, complex journey against time and tide for the ISRA team – but a giant leap for shark conservation. As Dr Rima Jabado, chair of the IUCN SSC Shark Specialist Group, says, ‘Sharks, rays and chimaeras are facing a biodiversity crisis, with an estimated 37% of species considered threatened and at risk of extinction. While we have made incredible progress to conserve species, we need new approaches to complement fisheries and trade management actions. Delineating Important Shark and Ray Areas across the world’s oceans and inland waters will enable us to provide resource managers and decision-makers with the scientifically based actionable knowledge required for place-based conservation of sharks, rays and chimaeras. We are still at the early stages of this project, but I am confident that with our global network of members and other contributors, we will be able to make a difference and delineate ISRAs around the world by 2028.’

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