Stock Status within the North Sea Haddock

Saltmarsh landscapes (fig. 1) are common to Scotland. They are found in the intertidal zone (where the sea rises and falls between over the course of a day), in areas sheltered from the worst of the waves (NatureScot, 2023). They grow from the gentle settling of sediments into mud substrate, forming patches of vegetation separated by streams of water (Scottish Seabird Centre, n.d.). Their soils are waterlogged due to the frequent input of seawater, often resulting in the formation of peat (National Ocean Service, 2024). Saltmarshes are the mid to higher latitude equivalent of mangroves, which form in similar intertidal environments of the tropical latitudes (Davidson-Arnott, 2009). 

In terms of biodiversity, saltmarshes are incredibly important environments. They are the spawning grounds for many economically important fish species (The Wildlife Trusts, n.d.), and support communities of unique plants, small mammals, and lots of insects, in addition to their best-known residents – birds, be they permanent or migratory visitors (Scottish Seabird Centre, n.d.). 

Not only are these environments ecologically important, but they also provide more direct benefits to the human population. Their sediments can trap contaminants and improve water quality, while their complex structures are excellent flood defences (fig. 2) (Hudson, Kenworthy, and Best, 2021). They are also a significantly important component in the fight against climate change…. (Hudson, Kenworthy, and Best, 2021). 

Due to the anaerobic soil (lacking in oxygen), carbon that becomes incorporated into the soil via plant photosynthesis decays very slowly, potentially being stored for millenia if undisturbed (NOAA, n.d.). When stored in this coastal/marine enviornment, the carbon is known as ‘blue carbon’. Saltmarsh carbon burial is one of the most efficient natural methods of carbon sequestration (fig. 3), better than both seagrass and forests (Hudson, Kenworthy, and Best, 2021). This also means the loss of saltmarsh landscape is highly damaging – releasing the long-buried carbon back into the atmosphere and contributing to planetary warming.