The Global Centre for Risk and Innovation (GCRI)
Coastal and marine ecosystems, from mangroves and seagrass to coral reefs, kelp forests and the open ocean, support fisheries, protect shorelines and store carbon. They face fishing, coastal development, pollution, warming and acidification at once, and much of the ocean is observed only sparsely. This page sets out how marine biodiversity, fish stocks and coastal integrity are measured, how pressures interact, and what the evidence means for fisheries, coastal and marine authorities.
Marine biodiversity is the variety of life in coastal and ocean ecosystems, from mangroves and seagrass to coral reefs, kelp forests and the open ocean. It faces fishing, coastal development, pollution, warming and acidification at once, while much of the ocean is sparsely observed. Fish stocks, coral cover and mangrove extent are among the measures used.
The working screen behind this subject: its structure, terms and states. Names are placeholders and values illustrative.
Coastal and marine biodiversity · Wetland complex · Accounting year 4
| Water level regime | 0.7 | 0.5 | 1.0 |
| Native vegetation cover | 0.8 | 0.8 | 1.0 |
| Invasive species pressure | 0.3 | 0.3 | 0.0 |
| Connectivity | 0.5 | 0.6 | 1.0 |
Marine ecosystems, fish stocks and coastal integrity. The dossier below sets out how the risk develops, what is measured, where the data come from, how it is modelled and who decides.
Fishing beyond what stocks can replace reduces abundance, shifts catches toward smaller species and removes predators that structure food webs. Bycatch affects seabirds, turtles, sharks and marine mammals, and illegal fishing hides the true pressure.
Marine heatwaves bleach corals and kill kelp and seagrass; warming shifts species toward the poles and changes where stocks can be fished. Acidification lowers the saturation of the carbonate minerals that corals and shellfish need to build skeletons.
Mangroves, salt marshes and seagrass are cleared for aquaculture, ports and housing, and hemmed in by sea walls as sea level rises. Losing them removes nurseries for fish and natural buffers against storm surge.
Nutrient runoff from land fuels algal blooms and low-oxygen zones; weakened reefs recover more slowly from storms and heat. Declining coastal fisheries then reach food security, tourism revenue and the insurance of coastal property.
Each term as this page uses it. Where a standard-setting body defines the term, the wording follows that body.
| Term | Definition |
|---|---|
| Coral bleaching | The loss of the algae living in coral tissue under heat stress, which turns coral white and can kill it if stress persists. |
| Biologically sustainable fish stock | A stock at or above the abundance that can produce maximum sustainable yield; SDG indicator 14.4.1. |
| Marine heatwave | A period of unusually warm sea temperature relative to the local seasonal climate, lasting at least several days. |
| Coastal squeeze | The loss of intertidal habitat trapped between rising seas and fixed structures such as sea walls. |
Each indicator carries its unit, its cadence, the kind of source behind it and the evidence label a value would carry. No values are shown: a programme supplies them under its own authority.
| Indicator | Unit | Cadence | Source type | Label |
|---|---|---|---|---|
| Fish stocks within biologically sustainable levels | percent of assessed stocks | biennial | Stock assessments compiled under SDG indicator 14.4.1 | OFFICIAL |
| Live hard coral cover | percent of reef area surveyed | annual | Reef surveys and photo transects | OBSERVED |
| Mangrove extent | hectares | periodic | Satellite radar and optical classification | OBSERVED |
| Marine heatwave days | days per year above the seasonal threshold | daily, summarised annually | Satellite sea surface temperature | OBSERVED |
| Ocean surface pH | pH units | monthly | Moorings, ship surveys and models | ESTIMATED |
| Marine protected area coverage | percent of national waters | monthly | World Database on Protected Areas | DECLARED |
| Apparent fishing effort | hours of fishing per grid cell | daily | Vessel tracking from automatic identification systems | ESTIMATED |
| Coastal eutrophication | chlorophyll-a anomaly index | monthly | Satellite ocean colour | MODELLED |
The topic as a computational graph: named sources feed the methods, an evidence review gates the outputs, and the decisions stay with the authorities that hold them.
Fig. 02Nodes carry their type, two metric rows and a state; connectors show what feeds what; dashed frames name the owners; the timeline is the cadence. Design of the pipeline, not a record of a run.
Named public datasets and institutional records, each with its licence class. Sources by agreement are used only under their terms and never republished.
| Source | What it gives | Licence class |
|---|---|---|
| Ocean Biodiversity Information System (OBIS) | Marine species occurrence and abundance records | CC0, CC BY or CC BY-NC per dataset |
| FAO FishStat and the State of World Fisheries and Aquaculture | Capture, aquaculture and stock status statistics | Free and open, attribution |
| RAM Legacy Stock Assessment Database | Compiled biomass and fishing mortality series from stock assessments | Free and open, attribution |
| Global Mangrove Watch | Mangrove extent and change from satellite radar and optical data | Free and open, attribution |
| Allen Coral Atlas | Shallow reef habitat maps and bleaching monitoring | Free and open, attribution |
| Global Fishing Watch | Apparent fishing effort and vessel presence from vessel tracking | Free for non-commercial use, attribution |
| Copernicus Marine Service | Ocean temperature, currents, biogeochemistry and ocean colour | Free and open, attribution |
| Global Coral Reef Monitoring Network | Compiled reef survey data on coral and fish condition | Terms per data contributor |
Biodiversity Nexus prepares evidence. The decisions below are taken by the authorities named, under their own rules, and never by the platform.
| Who decides | The question | Evidence this page serves |
|---|---|---|
| Fisheries ministries and regional fisheries management organisations | What catch limits, closures and gear rules keep stocks within sustainable levels | Stock status and trend with assessment uncertainty; fishing effort maps |
| Marine protected-area and coastal zone authorities | Where to protect, how to manage, and whether protection is effective | Habitat maps, coverage and connectivity, condition inside and outside protection |
| Coastal planners and port authorities | Whether development removes mangroves, marshes or seagrass that protect the coast | Habitat extent and change, shoreline protection function, sea-level scenarios |
| Insurers and development finance institutions | Where reef and mangrove loss raises coastal flood losses, and what protection is worth financing | Habitat condition linked to exposure and flood models, each with its label |
Marine ecologists and fisheries scientists ask a recurring set of questions.
Marine ecosystems face three broad sets of pressure. Fishing removes biomass and can alter food webs when predators or grazers are depleted, and destructive gear damages seabed habitat. Coastal development and land-based runoff remove mangroves and marshes and deliver sediment and nutrients that smother reefs and seagrass. Climate change warms and acidifies the ocean, causing coral bleaching, shifting species towards the poles and deeper water, and changing the timing of productivity.
Habitat-forming species such as corals, mangroves, kelp and seagrass create the structure that many other species need, and they also dissipate wave energy and trap sediment. Their loss therefore reduces both biodiversity and coastal protection at once, raising erosion and flood exposure for the communities behind them.
Catch data, surveys and population models estimate stock status. Many stocks, particularly in small-scale fisheries, are data-poor.
Satellite, aerial and acoustic surveys map shallow habitats, through ocean and coastal science and Earth observation. Deeper and turbid waters are hard to observe.
Buoys, floats and satellites track temperature, chlorophyll and heatwaves. Biological observation at sea remains sparse.
Models estimate wave reduction by habitats. Results are sensitive to habitat condition and storm characteristics.
The current service level is R0: information and enquiries. An enquiry receives a reference and names the next step; applications, payments, compute allocations and registrations open only when their team, terms and review capacity exist.