Fish commonly eaten among major undersea engineers, according to research

Many of the fish we eat play an important role in maintaining the seabed. Convex seascape research scientists evaluated the role of fish in biological patrols (sedge cries and reprocessing) in shallow British seas. Their paper, published in the Journal Marine Environmental Research, is entitled “Fish Functional Evaluation as Bioter Bacter and Vulnerability to Local Extinction.”

Atlantic cod (a restaurant staple) has strode through the list of these important “ecosystem engineers” (along with Atlantic hugfish and European eels).

In total, 185 fish species were found to play a role in disruption. Of these, 120 are subject to commercial fishing.

“Sea sediments are the world’s largest organic carbon reservoir. What happens on the seabed due to our climate,” said the University of Exeter. Mara Fisher, a student who led the research.

“Depending on biological disturbances, it is extremely important for how the seabed absorbs and stores organic carbon, so this process is therefore essential to understanding how the oceans can absorb greenhouse gases and slow the rate of climate change.

“Biotransient is also important for the seabed and wider marine ecosystems.

“We really understand how invertebrates contribute to global bioturbation, but up until now we have been missing half of the story.

“Our research is the first to quantify the effects of biotranspiration in fish, indicating that they play an important, broad-ranging role.”

Over-fished and overlooked

“We found that the species with the highest impact of biotransformation is one of the most vulnerable species to threats such as commercial fishing,” said Professor Calum Roberts, co-author of the Ecology and Conservation Center at the Penlin Campus in Exeter, Cornwall.

“Many of the largest and most powerful miners and distances in submarine sediments, including giant skates, halibut and cod, are disrupted by all that they have disappeared from our oceans.

“These losses lead to a change in the size of the seabed ecosystem mechanisms, but they still turn into uncertainty.”

Researchers looked at records of all fish species living on the UK continental shelf and found that more than half plays a role in bioturbation, which forages, digs holes, and/or shifts sediment and excavates during construction.

These various methods of reworking sediments across fish size and bioturbation frequency have been used by researchers to calculate the various bio-combustion impact scores.

An example is:

European eel. Bioturbation mode: burrower. Bioturbation score (out of 125): 100. IUCN preservation status: Critically endangered species. Fishing is primarily done using traps and pheknets, and is considered delicate in many parts of Europe and Asia. To some extent, it is prepared as a dish such as smoked eels, eels and eel soups. Threats include climate change, diseases and parasites, habitat loss, pollutants and fisheries.

Atlantic cod. Bioturbation mode: Vertical excavator. Bioturbation score: 100. IUCN Status: Vulnerable. It is mainly caught using trolls and long linings and consumed in a variety of forms, including fish and chips, fresh fillets, salted cod, and cod liver oil. Threats include overfishing, climate change and habitat degradation. The population is declining in several parts of its range, particularly in the North Sea and the Western Atlantic.

A typical skate. Bioturbation mode: Side excavator. Bioturbation score: 50. IUCN Status: Critical at risk. Historically targeted by trolls and longlinings, this species is currently protected in several areas, but is often caught by chance (bycatch). The numbers have been significantly reduced due to overfishing. This species is vulnerable due to its large size, reduced growth rate and low reproductive rate. Approximately 40 eggs are laid every year, and it takes 11 years to reach maturity in each generation.

Black Seabream. Bioturbation Mode: Nest Builder. Bioturbation score: 36. IUCN Status: Minimal Concern. It was caught mainly using bottom trolls, guilnets, hooks and lines. Fishing during the spawning season in April and May can affect population replenishment. The bottom troll at this point may remove fish, nests and eggs.

Red Garnerd. Bioturbation Mode: Sediment Sieve. Bioturbation score: 16. IUCN Status: Minimal Concern. Historically, there has been no major interest in commercial fishing, but the species has targeted more in recent years (including Cornwall). They are mostly caught by trawlers. Currently, there is no management of Garnerd species in the EU. There is no minimum landing size or quota. This can lead to unsustainable fishing.

Julie Hawkins, another author of the study, said, “Everyone who has spent time in the water, whether snorkeling or diving, knows that fish are constantly digging up the seabed.

“It is hard to believe that such obvious and important activities are largely overlooked when it comes to understanding carbon burials in the ocean.”

Convex Seascape Survey is a partnership between the Blue Marine Foundation, Exeter University of Exeter, and Convex Group Limited. The ambitious five-year global research program is the biggest attempt to deepen the character and capabilities of the ocean and its continental shelf in the global carbon cycle, an urgent effort to slow climate change.