Tag Archives: fish

Meat boom propels China’s ecosystems into total collapse Updated for 2026





China’s push for more intense farming has kept its city dwellers well-fed and helped lift millions of rural workers out of poverty. But it has come at a cost.

Ecosystems in what should be one of the country’s most fertile region have already been badly damaged – some beyond repair – and the consequences will be felt across the world.

This is part of a long-running trade-off between rising levels of food production and a deteriorating environment, revealed in recent research I conducted with colleagues from China and the UK.

Yields of crops and fish have risen over the past 60 years at several locations we studied in Anhui, Jiangsu and Shanghai Provinces in eastern China. But these are parallelled by long-term trends in poorer air and water quality, and reduced soil stability.

You may ask if this a bad thing. After all, increasing agricultural productivity has been one of the factors responsible for lifting millions of rural Chinese out of poverty. Does it really matter that the natural environment has taken a bit of a hit?

Well yes. For agriculture and aquaculture to be sustainable from one generation to the next, the natural processes that stabilise soils, purify water or store carbon have to be maintained in stable states. These natural processes represent benefits for society, known as ecosystem services.

‘Green revolution’ technologies tip the balance to perdition

Throughout the latter half of the last century, these services were being lost relatively slowly through the cumulative, everyday actions of individual farmers.

But the problems accelerated in the 1980s when farmers began to use more intensive methods, especially artificial fertilisers – and again after 2004 when subsidies were introduced.

Worryingly, in some localities, the slow deterioration has turned into a rapid downward spiral. Some aquatic ecosystems have dropped over tipping points into new, undesirable states where clear lakes suddenly become dominated by green algae with losses of high-value fish.

These new states are not just detrimental to the continued high-level production of crops and fish but are very difficult and expensive to restore.

These natural processes are degraded and destabilised to the point that they cannot be depended upon to support intensive agriculture in the near future. The whole region is losing its ability to withstand the impact of extreme events, from typhoons to global commodity prices.

What can be done?

National policy must prioritise sustainable agriculture. This will mean big changes on the farm: fertiliser and pesticides must be applied in the correct quantities at the right time of the year, cattle slurry and human sewage must be disposed of properly, chemicals getting into streams and rivers must be reduced, and fish feed has to be controlled.

Unfortunately, this is easier said than done. Farmers are still generally poor, badly educated and ageing. Good agricultural advice is lacking and big cities still tempt the younger farmers away from their fields. All these factors mean that rapid action is unlikely.

The recent introduction of the Land Circulation reform policy, allows farmers to rent their land to larger combines. The policy is designed to overcome the inefficiencies of small farm holdings but it may not be taken up widely in the more marginal landscapes where potential profits are low.

All the evidence points to a need for a significantly improved system of information and technology transfer to individual smallholders, probably involving a more efficient coordination between agencies.

The problem is global

But there’s a larger-scale context to this problem that may affect us all. China’s grain production has risen fivefold since the 1950s, outstripping the pace of population growth. Despite this, the nation is no longer self-sufficient.

The shift towards more meat production has placed a demand for soybean and cereal animal feed that can no longer be met internally. In 2012, China imported more than 60% of all the world’s soybeans that were available for export, and cereal imports are also on the up.

Reliance on imports to fill a shortfall in home produce is nothing new. But in China’s case, the additional risk that agriculture is increasingly unsustainable may amplify the demand. The potential scale of demand for imports is bound to have repercussions for global food production and food prices.

Unless reforms are introduced quickly, the rest of the world may well find that they are sharing China’s trade-off with nature – through the weekly shopping bill.

 


 

John Dearing is Professor of Physical Geography at the University of Southampton.

This article was originally published on The Conversation. Read the original article.

The Conversation

 




390879

Meat boom propels China’s ecosystems into total collapse Updated for 2026





China’s push for more intense farming has kept its city dwellers well-fed and helped lift millions of rural workers out of poverty. But it has come at a cost.

Ecosystems in what should be one of the country’s most fertile region have already been badly damaged – some beyond repair – and the consequences will be felt across the world.

This is part of a long-running trade-off between rising levels of food production and a deteriorating environment, revealed in recent research I conducted with colleagues from China and the UK.

Yields of crops and fish have risen over the past 60 years at several locations we studied in Anhui, Jiangsu and Shanghai Provinces in eastern China. But these are parallelled by long-term trends in poorer air and water quality, and reduced soil stability.

You may ask if this a bad thing. After all, increasing agricultural productivity has been one of the factors responsible for lifting millions of rural Chinese out of poverty. Does it really matter that the natural environment has taken a bit of a hit?

Well yes. For agriculture and aquaculture to be sustainable from one generation to the next, the natural processes that stabilise soils, purify water or store carbon have to be maintained in stable states. These natural processes represent benefits for society, known as ecosystem services.

‘Green revolution’ technologies tip the balance to perdition

Throughout the latter half of the last century, these services were being lost relatively slowly through the cumulative, everyday actions of individual farmers.

But the problems accelerated in the 1980s when farmers began to use more intensive methods, especially artificial fertilisers – and again after 2004 when subsidies were introduced.

Worryingly, in some localities, the slow deterioration has turned into a rapid downward spiral. Some aquatic ecosystems have dropped over tipping points into new, undesirable states where clear lakes suddenly become dominated by green algae with losses of high-value fish.

These new states are not just detrimental to the continued high-level production of crops and fish but are very difficult and expensive to restore.

These natural processes are degraded and destabilised to the point that they cannot be depended upon to support intensive agriculture in the near future. The whole region is losing its ability to withstand the impact of extreme events, from typhoons to global commodity prices.

What can be done?

National policy must prioritise sustainable agriculture. This will mean big changes on the farm: fertiliser and pesticides must be applied in the correct quantities at the right time of the year, cattle slurry and human sewage must be disposed of properly, chemicals getting into streams and rivers must be reduced, and fish feed has to be controlled.

Unfortunately, this is easier said than done. Farmers are still generally poor, badly educated and ageing. Good agricultural advice is lacking and big cities still tempt the younger farmers away from their fields. All these factors mean that rapid action is unlikely.

The recent introduction of the Land Circulation reform policy, allows farmers to rent their land to larger combines. The policy is designed to overcome the inefficiencies of small farm holdings but it may not be taken up widely in the more marginal landscapes where potential profits are low.

All the evidence points to a need for a significantly improved system of information and technology transfer to individual smallholders, probably involving a more efficient coordination between agencies.

The problem is global

But there’s a larger-scale context to this problem that may affect us all. China’s grain production has risen fivefold since the 1950s, outstripping the pace of population growth. Despite this, the nation is no longer self-sufficient.

The shift towards more meat production has placed a demand for soybean and cereal animal feed that can no longer be met internally. In 2012, China imported more than 60% of all the world’s soybeans that were available for export, and cereal imports are also on the up.

Reliance on imports to fill a shortfall in home produce is nothing new. But in China’s case, the additional risk that agriculture is increasingly unsustainable may amplify the demand. The potential scale of demand for imports is bound to have repercussions for global food production and food prices.

Unless reforms are introduced quickly, the rest of the world may well find that they are sharing China’s trade-off with nature – through the weekly shopping bill.

 


 

John Dearing is Professor of Physical Geography at the University of Southampton.

This article was originally published on The Conversation. Read the original article.

The Conversation

 




390879

For the love of cod, let’s save our disappearing seagrass Updated for 2026





Seagrass is one of the most important coastal habitats where young ocean-going fish such as Atlantic cod can grow and develop before setting out on the journey of life.

But these critically important habitats, revealed in new research, are being damaged the world over and its not just threatening biodiversity but our food security.

Some 30,000 km2 of seagrass (Zostera marina) has disappeared over the past two decades, about 18% of the global area. This is incredibly important.

One hectare of seagrass absorbs 1.2 kilogrammes of nutrients each year, equivalent to the treated effluent of 200 people. It can produce 100,000 litres of oxygen per day, can support 80,000 fish and 100m invertebrates – and absorb ten times as much CO2 as a pristine area of Amazon rainforest.

A vital habitat for marine life

Providing shallow-water habitats where young ocean-going fish can grow and develop is one of the key ecosystem services that our coastal seas provide, but unfortunately we largely don’t recognise the value of them in supporting the fishery resources of vast ocean basins.

We continue to allow the loss of this coastal habitat to occur throughout the world – in spite of regulations in many nations to protect key habitats and biodiversity.

The diminished status of fisheries for species such as the Atlantic cod (Gadus morhua) means we need to move beyond purely managing adult fish stocks and consider the interaction of individual high-value species within the whole seascape and the critical habitats within that.

This is critical as our declining fishery stocks do not align with the needs of the region or the planet as a whole. To meet the needs of the predicted human population of 2050, an additional 75m tons of protein from fish and aquatic invertebrates will be required – this is a 50% increase in current supply.

Seagrass as a nursery for juvenile cod

The Atlantic cod is a species of significant economic and historic importance but is now better known for its catastrophic decline. Apart from overfishing, the causes of this decline and its subsequent lack of recovery remain largely unresolved.

The degree to which specific coastal and shallow-water habitats are important for this species still remains unquantified at the scale of the North Atlantic.

There is extensive evidence of the presence of juvenile Atlantic cod in seagrass throughout the North Atlantic. Juvenile cod have been recorded in such high density in seagrass that they average 246 individuals per hectare.

This density of juvenile Atlantic cod is higher in seagrass meadows compared to alternative habitats. This includes an incredible dataset from Norway where researchers have sampled juvenile cod in seagrass annually since 1919 and other recent studies observing juvenile cod in seagrass in North Wales by our team at Swansea University using stereo Baited Remote Underwater Video systems and seine nets.

Juvenile Atlantic cod have greater long-term viability after having spent time in seagrass, which improves their chances of reaching maturity. Our new analysis, published in the open access journal, Global Ecology and Conservation, illustrates how juvenile Atlantic cod grow faster in seagrass than in surrounding alternative habitat types and have higher survival rates from predation.

Although juvenile Atlantic cod do not always need to use seagrass meadows as juvenile habitats, it appears that they may intentionally select seagrass as a nursery habitat. This data comes from studies throughout the Atlantic including Newfoundland in the west and Sweden in the east.

Biodiversity and food security

The study, conducted in collaboration with Richard Lilley at Cardiff University, was an extensive meta-analysis of research on the life history of the Atlantic cod resulting in a review and synthesis of its nursery habitat usage.

It includes data sources from throughout the region, ranging from Newfoundland, to Norway, to Scotland and to Sweden.

Our work provides strong evidence that seagrass meadows are of significant importance to contributing to Atlantic cod stocks, and our review presents extensive quantitative evidence of the role of seagrass as valuable nursery habitat for Atlantic cod. These findings are of major significance given the continued threats to these systems.

Seagrass meadows are globally important resources that are being threatened by a whole series of issues ranging from climate change and major weather events to boating activity, poor water quality and coastal development.

This work clearly illustrates how key habitats in our coastal seas such as seagrass need protecting, not just for biodiversity but for the continued food security provided by our oceans.

 


 

Richard K.F. Unsworth is Research Officer (Marine Ecology) at the University of Swansea. He does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

This article was originally published on The Conversation. Read the original article.

The Conversation

 




386327

For the love of cod, let’s save our disappearing seagrass Updated for 2026





Seagrass is one of the most important coastal habitats where young ocean-going fish such as Atlantic cod can grow and develop before setting out on the journey of life.

But these critically important habitats, revealed in new research, are being damaged the world over and its not just threatening biodiversity but our food security.

Some 30,000 km2 of seagrass (Zostera marina) has disappeared over the past two decades, about 18% of the global area. This is incredibly important.

One hectare of seagrass absorbs 1.2 kilogrammes of nutrients each year, equivalent to the treated effluent of 200 people. It can produce 100,000 litres of oxygen per day, can support 80,000 fish and 100m invertebrates – and absorb ten times as much CO2 as a pristine area of Amazon rainforest.

A vital habitat for marine life

Providing shallow-water habitats where young ocean-going fish can grow and develop is one of the key ecosystem services that our coastal seas provide, but unfortunately we largely don’t recognise the value of them in supporting the fishery resources of vast ocean basins.

We continue to allow the loss of this coastal habitat to occur throughout the world – in spite of regulations in many nations to protect key habitats and biodiversity.

The diminished status of fisheries for species such as the Atlantic cod (Gadus morhua) means we need to move beyond purely managing adult fish stocks and consider the interaction of individual high-value species within the whole seascape and the critical habitats within that.

This is critical as our declining fishery stocks do not align with the needs of the region or the planet as a whole. To meet the needs of the predicted human population of 2050, an additional 75m tons of protein from fish and aquatic invertebrates will be required – this is a 50% increase in current supply.

Seagrass as a nursery for juvenile cod

The Atlantic cod is a species of significant economic and historic importance but is now better known for its catastrophic decline. Apart from overfishing, the causes of this decline and its subsequent lack of recovery remain largely unresolved.

The degree to which specific coastal and shallow-water habitats are important for this species still remains unquantified at the scale of the North Atlantic.

There is extensive evidence of the presence of juvenile Atlantic cod in seagrass throughout the North Atlantic. Juvenile cod have been recorded in such high density in seagrass that they average 246 individuals per hectare.

This density of juvenile Atlantic cod is higher in seagrass meadows compared to alternative habitats. This includes an incredible dataset from Norway where researchers have sampled juvenile cod in seagrass annually since 1919 and other recent studies observing juvenile cod in seagrass in North Wales by our team at Swansea University using stereo Baited Remote Underwater Video systems and seine nets.

Juvenile Atlantic cod have greater long-term viability after having spent time in seagrass, which improves their chances of reaching maturity. Our new analysis, published in the open access journal, Global Ecology and Conservation, illustrates how juvenile Atlantic cod grow faster in seagrass than in surrounding alternative habitat types and have higher survival rates from predation.

Although juvenile Atlantic cod do not always need to use seagrass meadows as juvenile habitats, it appears that they may intentionally select seagrass as a nursery habitat. This data comes from studies throughout the Atlantic including Newfoundland in the west and Sweden in the east.

Biodiversity and food security

The study, conducted in collaboration with Richard Lilley at Cardiff University, was an extensive meta-analysis of research on the life history of the Atlantic cod resulting in a review and synthesis of its nursery habitat usage.

It includes data sources from throughout the region, ranging from Newfoundland, to Norway, to Scotland and to Sweden.

Our work provides strong evidence that seagrass meadows are of significant importance to contributing to Atlantic cod stocks, and our review presents extensive quantitative evidence of the role of seagrass as valuable nursery habitat for Atlantic cod. These findings are of major significance given the continued threats to these systems.

Seagrass meadows are globally important resources that are being threatened by a whole series of issues ranging from climate change and major weather events to boating activity, poor water quality and coastal development.

This work clearly illustrates how key habitats in our coastal seas such as seagrass need protecting, not just for biodiversity but for the continued food security provided by our oceans.

 


 

Richard K.F. Unsworth is Research Officer (Marine Ecology) at the University of Swansea. He does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

This article was originally published on The Conversation. Read the original article.

The Conversation

 




386327

For the love of cod, let’s save our disappearing seagrass Updated for 2026





Seagrass is one of the most important coastal habitats where young ocean-going fish such as Atlantic cod can grow and develop before setting out on the journey of life.

But these critically important habitats, revealed in new research, are being damaged the world over and its not just threatening biodiversity but our food security.

Some 30,000 km2 of seagrass (Zostera marina) has disappeared over the past two decades, about 18% of the global area. This is incredibly important.

One hectare of seagrass absorbs 1.2 kilogrammes of nutrients each year, equivalent to the treated effluent of 200 people. It can produce 100,000 litres of oxygen per day, can support 80,000 fish and 100m invertebrates – and absorb ten times as much CO2 as a pristine area of Amazon rainforest.

A vital habitat for marine life

Providing shallow-water habitats where young ocean-going fish can grow and develop is one of the key ecosystem services that our coastal seas provide, but unfortunately we largely don’t recognise the value of them in supporting the fishery resources of vast ocean basins.

We continue to allow the loss of this coastal habitat to occur throughout the world – in spite of regulations in many nations to protect key habitats and biodiversity.

The diminished status of fisheries for species such as the Atlantic cod (Gadus morhua) means we need to move beyond purely managing adult fish stocks and consider the interaction of individual high-value species within the whole seascape and the critical habitats within that.

This is critical as our declining fishery stocks do not align with the needs of the region or the planet as a whole. To meet the needs of the predicted human population of 2050, an additional 75m tons of protein from fish and aquatic invertebrates will be required – this is a 50% increase in current supply.

Seagrass as a nursery for juvenile cod

The Atlantic cod is a species of significant economic and historic importance but is now better known for its catastrophic decline. Apart from overfishing, the causes of this decline and its subsequent lack of recovery remain largely unresolved.

The degree to which specific coastal and shallow-water habitats are important for this species still remains unquantified at the scale of the North Atlantic.

There is extensive evidence of the presence of juvenile Atlantic cod in seagrass throughout the North Atlantic. Juvenile cod have been recorded in such high density in seagrass that they average 246 individuals per hectare.

This density of juvenile Atlantic cod is higher in seagrass meadows compared to alternative habitats. This includes an incredible dataset from Norway where researchers have sampled juvenile cod in seagrass annually since 1919 and other recent studies observing juvenile cod in seagrass in North Wales by our team at Swansea University using stereo Baited Remote Underwater Video systems and seine nets.

Juvenile Atlantic cod have greater long-term viability after having spent time in seagrass, which improves their chances of reaching maturity. Our new analysis, published in the open access journal, Global Ecology and Conservation, illustrates how juvenile Atlantic cod grow faster in seagrass than in surrounding alternative habitat types and have higher survival rates from predation.

Although juvenile Atlantic cod do not always need to use seagrass meadows as juvenile habitats, it appears that they may intentionally select seagrass as a nursery habitat. This data comes from studies throughout the Atlantic including Newfoundland in the west and Sweden in the east.

Biodiversity and food security

The study, conducted in collaboration with Richard Lilley at Cardiff University, was an extensive meta-analysis of research on the life history of the Atlantic cod resulting in a review and synthesis of its nursery habitat usage.

It includes data sources from throughout the region, ranging from Newfoundland, to Norway, to Scotland and to Sweden.

Our work provides strong evidence that seagrass meadows are of significant importance to contributing to Atlantic cod stocks, and our review presents extensive quantitative evidence of the role of seagrass as valuable nursery habitat for Atlantic cod. These findings are of major significance given the continued threats to these systems.

Seagrass meadows are globally important resources that are being threatened by a whole series of issues ranging from climate change and major weather events to boating activity, poor water quality and coastal development.

This work clearly illustrates how key habitats in our coastal seas such as seagrass need protecting, not just for biodiversity but for the continued food security provided by our oceans.

 


 

Richard K.F. Unsworth is Research Officer (Marine Ecology) at the University of Swansea. He does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

This article was originally published on The Conversation. Read the original article.

The Conversation

 




386327

For the love of cod, let’s save our disappearing seagrass Updated for 2026





Seagrass is one of the most important coastal habitats where young ocean-going fish such as Atlantic cod can grow and develop before setting out on the journey of life.

But these critically important habitats, revealed in new research, are being damaged the world over and its not just threatening biodiversity but our food security.

Some 30,000 km2 of seagrass (Zostera marina) has disappeared over the past two decades, about 18% of the global area. This is incredibly important.

One hectare of seagrass absorbs 1.2 kilogrammes of nutrients each year, equivalent to the treated effluent of 200 people. It can produce 100,000 litres of oxygen per day, can support 80,000 fish and 100m invertebrates – and absorb ten times as much CO2 as a pristine area of Amazon rainforest.

A vital habitat for marine life

Providing shallow-water habitats where young ocean-going fish can grow and develop is one of the key ecosystem services that our coastal seas provide, but unfortunately we largely don’t recognise the value of them in supporting the fishery resources of vast ocean basins.

We continue to allow the loss of this coastal habitat to occur throughout the world – in spite of regulations in many nations to protect key habitats and biodiversity.

The diminished status of fisheries for species such as the Atlantic cod (Gadus morhua) means we need to move beyond purely managing adult fish stocks and consider the interaction of individual high-value species within the whole seascape and the critical habitats within that.

This is critical as our declining fishery stocks do not align with the needs of the region or the planet as a whole. To meet the needs of the predicted human population of 2050, an additional 75m tons of protein from fish and aquatic invertebrates will be required – this is a 50% increase in current supply.

Seagrass as a nursery for juvenile cod

The Atlantic cod is a species of significant economic and historic importance but is now better known for its catastrophic decline. Apart from overfishing, the causes of this decline and its subsequent lack of recovery remain largely unresolved.

The degree to which specific coastal and shallow-water habitats are important for this species still remains unquantified at the scale of the North Atlantic.

There is extensive evidence of the presence of juvenile Atlantic cod in seagrass throughout the North Atlantic. Juvenile cod have been recorded in such high density in seagrass that they average 246 individuals per hectare.

This density of juvenile Atlantic cod is higher in seagrass meadows compared to alternative habitats. This includes an incredible dataset from Norway where researchers have sampled juvenile cod in seagrass annually since 1919 and other recent studies observing juvenile cod in seagrass in North Wales by our team at Swansea University using stereo Baited Remote Underwater Video systems and seine nets.

Juvenile Atlantic cod have greater long-term viability after having spent time in seagrass, which improves their chances of reaching maturity. Our new analysis, published in the open access journal, Global Ecology and Conservation, illustrates how juvenile Atlantic cod grow faster in seagrass than in surrounding alternative habitat types and have higher survival rates from predation.

Although juvenile Atlantic cod do not always need to use seagrass meadows as juvenile habitats, it appears that they may intentionally select seagrass as a nursery habitat. This data comes from studies throughout the Atlantic including Newfoundland in the west and Sweden in the east.

Biodiversity and food security

The study, conducted in collaboration with Richard Lilley at Cardiff University, was an extensive meta-analysis of research on the life history of the Atlantic cod resulting in a review and synthesis of its nursery habitat usage.

It includes data sources from throughout the region, ranging from Newfoundland, to Norway, to Scotland and to Sweden.

Our work provides strong evidence that seagrass meadows are of significant importance to contributing to Atlantic cod stocks, and our review presents extensive quantitative evidence of the role of seagrass as valuable nursery habitat for Atlantic cod. These findings are of major significance given the continued threats to these systems.

Seagrass meadows are globally important resources that are being threatened by a whole series of issues ranging from climate change and major weather events to boating activity, poor water quality and coastal development.

This work clearly illustrates how key habitats in our coastal seas such as seagrass need protecting, not just for biodiversity but for the continued food security provided by our oceans.

 


 

Richard K.F. Unsworth is Research Officer (Marine Ecology) at the University of Swansea. He does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

This article was originally published on The Conversation. Read the original article.

The Conversation

 




386327

For the love of cod, let’s save our disappearing seagrass Updated for 2026





Seagrass is one of the most important coastal habitats where young ocean-going fish such as Atlantic cod can grow and develop before setting out on the journey of life.

But these critically important habitats, revealed in new research, are being damaged the world over and its not just threatening biodiversity but our food security.

Some 30,000 km2 of seagrass (Zostera marina) has disappeared over the past two decades, about 18% of the global area. This is incredibly important.

One hectare of seagrass absorbs 1.2 kilogrammes of nutrients each year, equivalent to the treated effluent of 200 people. It can produce 100,000 litres of oxygen per day, can support 80,000 fish and 100m invertebrates – and absorb ten times as much CO2 as a pristine area of Amazon rainforest.

A vital habitat for marine life

Providing shallow-water habitats where young ocean-going fish can grow and develop is one of the key ecosystem services that our coastal seas provide, but unfortunately we largely don’t recognise the value of them in supporting the fishery resources of vast ocean basins.

We continue to allow the loss of this coastal habitat to occur throughout the world – in spite of regulations in many nations to protect key habitats and biodiversity.

The diminished status of fisheries for species such as the Atlantic cod (Gadus morhua) means we need to move beyond purely managing adult fish stocks and consider the interaction of individual high-value species within the whole seascape and the critical habitats within that.

This is critical as our declining fishery stocks do not align with the needs of the region or the planet as a whole. To meet the needs of the predicted human population of 2050, an additional 75m tons of protein from fish and aquatic invertebrates will be required – this is a 50% increase in current supply.

Seagrass as a nursery for juvenile cod

The Atlantic cod is a species of significant economic and historic importance but is now better known for its catastrophic decline. Apart from overfishing, the causes of this decline and its subsequent lack of recovery remain largely unresolved.

The degree to which specific coastal and shallow-water habitats are important for this species still remains unquantified at the scale of the North Atlantic.

There is extensive evidence of the presence of juvenile Atlantic cod in seagrass throughout the North Atlantic. Juvenile cod have been recorded in such high density in seagrass that they average 246 individuals per hectare.

This density of juvenile Atlantic cod is higher in seagrass meadows compared to alternative habitats. This includes an incredible dataset from Norway where researchers have sampled juvenile cod in seagrass annually since 1919 and other recent studies observing juvenile cod in seagrass in North Wales by our team at Swansea University using stereo Baited Remote Underwater Video systems and seine nets.

Juvenile Atlantic cod have greater long-term viability after having spent time in seagrass, which improves their chances of reaching maturity. Our new analysis, published in the open access journal, Global Ecology and Conservation, illustrates how juvenile Atlantic cod grow faster in seagrass than in surrounding alternative habitat types and have higher survival rates from predation.

Although juvenile Atlantic cod do not always need to use seagrass meadows as juvenile habitats, it appears that they may intentionally select seagrass as a nursery habitat. This data comes from studies throughout the Atlantic including Newfoundland in the west and Sweden in the east.

Biodiversity and food security

The study, conducted in collaboration with Richard Lilley at Cardiff University, was an extensive meta-analysis of research on the life history of the Atlantic cod resulting in a review and synthesis of its nursery habitat usage.

It includes data sources from throughout the region, ranging from Newfoundland, to Norway, to Scotland and to Sweden.

Our work provides strong evidence that seagrass meadows are of significant importance to contributing to Atlantic cod stocks, and our review presents extensive quantitative evidence of the role of seagrass as valuable nursery habitat for Atlantic cod. These findings are of major significance given the continued threats to these systems.

Seagrass meadows are globally important resources that are being threatened by a whole series of issues ranging from climate change and major weather events to boating activity, poor water quality and coastal development.

This work clearly illustrates how key habitats in our coastal seas such as seagrass need protecting, not just for biodiversity but for the continued food security provided by our oceans.

 


 

Richard K.F. Unsworth is Research Officer (Marine Ecology) at the University of Swansea. He does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

This article was originally published on The Conversation. Read the original article.

The Conversation

 




386327

For the love of cod, let’s save our disappearing seagrass Updated for 2026





Seagrass is one of the most important coastal habitats where young ocean-going fish such as Atlantic cod can grow and develop before setting out on the journey of life.

But these critically important habitats, revealed in new research, are being damaged the world over and its not just threatening biodiversity but our food security.

Some 30,000 km2 of seagrass (Zostera marina) has disappeared over the past two decades, about 18% of the global area. This is incredibly important.

One hectare of seagrass absorbs 1.2 kilogrammes of nutrients each year, equivalent to the treated effluent of 200 people. It can produce 100,000 litres of oxygen per day, can support 80,000 fish and 100m invertebrates – and absorb ten times as much CO2 as a pristine area of Amazon rainforest.

A vital habitat for marine life

Providing shallow-water habitats where young ocean-going fish can grow and develop is one of the key ecosystem services that our coastal seas provide, but unfortunately we largely don’t recognise the value of them in supporting the fishery resources of vast ocean basins.

We continue to allow the loss of this coastal habitat to occur throughout the world – in spite of regulations in many nations to protect key habitats and biodiversity.

The diminished status of fisheries for species such as the Atlantic cod (Gadus morhua) means we need to move beyond purely managing adult fish stocks and consider the interaction of individual high-value species within the whole seascape and the critical habitats within that.

This is critical as our declining fishery stocks do not align with the needs of the region or the planet as a whole. To meet the needs of the predicted human population of 2050, an additional 75m tons of protein from fish and aquatic invertebrates will be required – this is a 50% increase in current supply.

Seagrass as a nursery for juvenile cod

The Atlantic cod is a species of significant economic and historic importance but is now better known for its catastrophic decline. Apart from overfishing, the causes of this decline and its subsequent lack of recovery remain largely unresolved.

The degree to which specific coastal and shallow-water habitats are important for this species still remains unquantified at the scale of the North Atlantic.

There is extensive evidence of the presence of juvenile Atlantic cod in seagrass throughout the North Atlantic. Juvenile cod have been recorded in such high density in seagrass that they average 246 individuals per hectare.

This density of juvenile Atlantic cod is higher in seagrass meadows compared to alternative habitats. This includes an incredible dataset from Norway where researchers have sampled juvenile cod in seagrass annually since 1919 and other recent studies observing juvenile cod in seagrass in North Wales by our team at Swansea University using stereo Baited Remote Underwater Video systems and seine nets.

Juvenile Atlantic cod have greater long-term viability after having spent time in seagrass, which improves their chances of reaching maturity. Our new analysis, published in the open access journal, Global Ecology and Conservation, illustrates how juvenile Atlantic cod grow faster in seagrass than in surrounding alternative habitat types and have higher survival rates from predation.

Although juvenile Atlantic cod do not always need to use seagrass meadows as juvenile habitats, it appears that they may intentionally select seagrass as a nursery habitat. This data comes from studies throughout the Atlantic including Newfoundland in the west and Sweden in the east.

Biodiversity and food security

The study, conducted in collaboration with Richard Lilley at Cardiff University, was an extensive meta-analysis of research on the life history of the Atlantic cod resulting in a review and synthesis of its nursery habitat usage.

It includes data sources from throughout the region, ranging from Newfoundland, to Norway, to Scotland and to Sweden.

Our work provides strong evidence that seagrass meadows are of significant importance to contributing to Atlantic cod stocks, and our review presents extensive quantitative evidence of the role of seagrass as valuable nursery habitat for Atlantic cod. These findings are of major significance given the continued threats to these systems.

Seagrass meadows are globally important resources that are being threatened by a whole series of issues ranging from climate change and major weather events to boating activity, poor water quality and coastal development.

This work clearly illustrates how key habitats in our coastal seas such as seagrass need protecting, not just for biodiversity but for the continued food security provided by our oceans.

 


 

Richard K.F. Unsworth is Research Officer (Marine Ecology) at the University of Swansea. He does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

This article was originally published on The Conversation. Read the original article.

The Conversation

 




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For the love of cod, let’s save our disappearing seagrass Updated for 2026





Seagrass is one of the most important coastal habitats where young ocean-going fish such as Atlantic cod can grow and develop before setting out on the journey of life.

But these critically important habitats, revealed in new research, are being damaged the world over and its not just threatening biodiversity but our food security.

Some 30,000 km2 of seagrass (Zostera marina) has disappeared over the past two decades, about 18% of the global area. This is incredibly important.

One hectare of seagrass absorbs 1.2 kilogrammes of nutrients each year, equivalent to the treated effluent of 200 people. It can produce 100,000 litres of oxygen per day, can support 80,000 fish and 100m invertebrates – and absorb ten times as much CO2 as a pristine area of Amazon rainforest.

A vital habitat for marine life

Providing shallow-water habitats where young ocean-going fish can grow and develop is one of the key ecosystem services that our coastal seas provide, but unfortunately we largely don’t recognise the value of them in supporting the fishery resources of vast ocean basins.

We continue to allow the loss of this coastal habitat to occur throughout the world – in spite of regulations in many nations to protect key habitats and biodiversity.

The diminished status of fisheries for species such as the Atlantic cod (Gadus morhua) means we need to move beyond purely managing adult fish stocks and consider the interaction of individual high-value species within the whole seascape and the critical habitats within that.

This is critical as our declining fishery stocks do not align with the needs of the region or the planet as a whole. To meet the needs of the predicted human population of 2050, an additional 75m tons of protein from fish and aquatic invertebrates will be required – this is a 50% increase in current supply.

Seagrass as a nursery for juvenile cod

The Atlantic cod is a species of significant economic and historic importance but is now better known for its catastrophic decline. Apart from overfishing, the causes of this decline and its subsequent lack of recovery remain largely unresolved.

The degree to which specific coastal and shallow-water habitats are important for this species still remains unquantified at the scale of the North Atlantic.

There is extensive evidence of the presence of juvenile Atlantic cod in seagrass throughout the North Atlantic. Juvenile cod have been recorded in such high density in seagrass that they average 246 individuals per hectare.

This density of juvenile Atlantic cod is higher in seagrass meadows compared to alternative habitats. This includes an incredible dataset from Norway where researchers have sampled juvenile cod in seagrass annually since 1919 and other recent studies observing juvenile cod in seagrass in North Wales by our team at Swansea University using stereo Baited Remote Underwater Video systems and seine nets.

Juvenile Atlantic cod have greater long-term viability after having spent time in seagrass, which improves their chances of reaching maturity. Our new analysis, published in the open access journal, Global Ecology and Conservation, illustrates how juvenile Atlantic cod grow faster in seagrass than in surrounding alternative habitat types and have higher survival rates from predation.

Although juvenile Atlantic cod do not always need to use seagrass meadows as juvenile habitats, it appears that they may intentionally select seagrass as a nursery habitat. This data comes from studies throughout the Atlantic including Newfoundland in the west and Sweden in the east.

Biodiversity and food security

The study, conducted in collaboration with Richard Lilley at Cardiff University, was an extensive meta-analysis of research on the life history of the Atlantic cod resulting in a review and synthesis of its nursery habitat usage.

It includes data sources from throughout the region, ranging from Newfoundland, to Norway, to Scotland and to Sweden.

Our work provides strong evidence that seagrass meadows are of significant importance to contributing to Atlantic cod stocks, and our review presents extensive quantitative evidence of the role of seagrass as valuable nursery habitat for Atlantic cod. These findings are of major significance given the continued threats to these systems.

Seagrass meadows are globally important resources that are being threatened by a whole series of issues ranging from climate change and major weather events to boating activity, poor water quality and coastal development.

This work clearly illustrates how key habitats in our coastal seas such as seagrass need protecting, not just for biodiversity but for the continued food security provided by our oceans.

 


 

Richard K.F. Unsworth is Research Officer (Marine Ecology) at the University of Swansea. He does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

This article was originally published on The Conversation. Read the original article.

The Conversation

 




386327

For the love of cod, let’s save our disappearing seagrass Updated for 2026





Seagrass is one of the most important coastal habitats where young ocean-going fish such as Atlantic cod can grow and develop before setting out on the journey of life.

But these critically important habitats, revealed in new research, are being damaged the world over and its not just threatening biodiversity but our food security.

Some 30,000 km2 of seagrass (Zostera marina) has disappeared over the past two decades, about 18% of the global area. This is incredibly important.

One hectare of seagrass absorbs 1.2 kilogrammes of nutrients each year, equivalent to the treated effluent of 200 people. It can produce 100,000 litres of oxygen per day, can support 80,000 fish and 100m invertebrates – and absorb ten times as much CO2 as a pristine area of Amazon rainforest.

A vital habitat for marine life

Providing shallow-water habitats where young ocean-going fish can grow and develop is one of the key ecosystem services that our coastal seas provide, but unfortunately we largely don’t recognise the value of them in supporting the fishery resources of vast ocean basins.

We continue to allow the loss of this coastal habitat to occur throughout the world – in spite of regulations in many nations to protect key habitats and biodiversity.

The diminished status of fisheries for species such as the Atlantic cod (Gadus morhua) means we need to move beyond purely managing adult fish stocks and consider the interaction of individual high-value species within the whole seascape and the critical habitats within that.

This is critical as our declining fishery stocks do not align with the needs of the region or the planet as a whole. To meet the needs of the predicted human population of 2050, an additional 75m tons of protein from fish and aquatic invertebrates will be required – this is a 50% increase in current supply.

Seagrass as a nursery for juvenile cod

The Atlantic cod is a species of significant economic and historic importance but is now better known for its catastrophic decline. Apart from overfishing, the causes of this decline and its subsequent lack of recovery remain largely unresolved.

The degree to which specific coastal and shallow-water habitats are important for this species still remains unquantified at the scale of the North Atlantic.

There is extensive evidence of the presence of juvenile Atlantic cod in seagrass throughout the North Atlantic. Juvenile cod have been recorded in such high density in seagrass that they average 246 individuals per hectare.

This density of juvenile Atlantic cod is higher in seagrass meadows compared to alternative habitats. This includes an incredible dataset from Norway where researchers have sampled juvenile cod in seagrass annually since 1919 and other recent studies observing juvenile cod in seagrass in North Wales by our team at Swansea University using stereo Baited Remote Underwater Video systems and seine nets.

Juvenile Atlantic cod have greater long-term viability after having spent time in seagrass, which improves their chances of reaching maturity. Our new analysis, published in the open access journal, Global Ecology and Conservation, illustrates how juvenile Atlantic cod grow faster in seagrass than in surrounding alternative habitat types and have higher survival rates from predation.

Although juvenile Atlantic cod do not always need to use seagrass meadows as juvenile habitats, it appears that they may intentionally select seagrass as a nursery habitat. This data comes from studies throughout the Atlantic including Newfoundland in the west and Sweden in the east.

Biodiversity and food security

The study, conducted in collaboration with Richard Lilley at Cardiff University, was an extensive meta-analysis of research on the life history of the Atlantic cod resulting in a review and synthesis of its nursery habitat usage.

It includes data sources from throughout the region, ranging from Newfoundland, to Norway, to Scotland and to Sweden.

Our work provides strong evidence that seagrass meadows are of significant importance to contributing to Atlantic cod stocks, and our review presents extensive quantitative evidence of the role of seagrass as valuable nursery habitat for Atlantic cod. These findings are of major significance given the continued threats to these systems.

Seagrass meadows are globally important resources that are being threatened by a whole series of issues ranging from climate change and major weather events to boating activity, poor water quality and coastal development.

This work clearly illustrates how key habitats in our coastal seas such as seagrass need protecting, not just for biodiversity but for the continued food security provided by our oceans.

 


 

Richard K.F. Unsworth is Research Officer (Marine Ecology) at the University of Swansea. He does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

This article was originally published on The Conversation. Read the original article.

The Conversation

 




386327