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Rebecca Dolson

Over fishing: How can scientists tell?

By | Ocean Solutions | 4 Comments


What is “MSY”?

In the news, we often hear that global fish populations are over-exploited, declining, or have collapsed. For example, the FAO (2010) reports that up to 85% of the global fisheries are being fished at the populations’ maximum sustainable yield, are over-exploited, depleted, or recovering from being depleted.

What is the threshold or benchmark that a scientist or fisheries manager uses to say “Yes, this population is being over-exploited!” Or, in the worst case scenario “The population has collapsed.”

Many organizations rely on the traditional benchmark of Maximum Sustainable Yield, otherwise known as MSY.


Figure 19 – State of the World Fisheries and Aquaculture 2010

You can think of MSY like this: start with a fish population that is not exploited (no one fishes it). Left on their own the population will increase to a carrying capacity. The populations’ carrying capacity is exceeded when any more fish in the population would not survive because there are not enough resources to support any new individuals.

Now, suppose that a fish population is at its carrying capacity and every year some number of fish are caught in the fishery.  Fish caught and harvested (removed from the population) by the fishery would free up resources for young fish to enter the population, thereby allowing the population to return to its carrying capacity. The key here is that there has to be enough individual fish left, after fishing, to reproduce enough young fish and maintain population growth. So, MSY is the maximum sustainable catch (yield) of fish per year from a population by the fishery that will not result in a population decline.

This graph shows theMSY theory of maximum sustainable yield. The X-axis is fishing mortality, or effort expended to capture the fish, and the Y axis is the average number of fish caught, or yield. As long as the fishery does not take more fish than the recommended MSY, on the left hand side of the graph, the fish population will continue to sustain itself and the fishery can continue.

If more fish are caught annually than the recommended MSY, the right hand side of the graph, fishing effort may increase but the average catch would decline. This is because the remaining fish population cannot reproduce enough new individuals to compensate for the number of individuals being taken by the fishing industry. If fishermen continue to catch more than the MSY, for many years, they begin to deplete the population (sometimes recodferred to as stock size). When a population is severely depleted it is called ‘collapsed’. In Canada, the most famous fishery collapse is that of the cod.

To maintain populations that can sustain fishing, fisheries managers try to set fishing quotas at or below the MSY. Often, poor data quality leads to an overestimate of the MSY and fishing quotas that can result in population decline or collapse.

Now when you hear in the news that a fish population is over-exploited, over-harvested, or fished beyond its MSY – you’ll know exactly what that means!

This article by World Wildlife Fund gives more details on other sub-categories of MSY that you may find in fishery management reports (click here!)

There are many limitations of the MSY benchmark. MSY is usually a single fish species estimate limiting our ability to understand the influence of species interaction, it often does not account for year to year variability in climate or other environmental variables, and it takes A LOT of data to come up with a ‘good’ estimate of MSY, because it also requires estimating the populations’ carrying capacity.

Are there any other options for management benchmarks?

Multi-species and ecosystem-based management approaches have been making a big splash lately. Ecosystem-based management focuses on not just the abundance of one fish population, but the fish habitat, by-catch of a fishery, food-web effects, and genetic diversity. When we manage at the level of an ecosystem rather than individual species it is possible to set goals to sustain healthy ecosystems and implement policies that protect the structure and function of the whole ecosystem which will inevitably help sustain the target fish populations.

Shark Finning and Shark Fishing: What’s the Difference?

By | Ocean News | 8 Comments


All around the world sharks are fished in commercial and recreational fisheries. Sharks and shark products are sold in domestic and foreign markets as food, for use in medicinal products, and as an ingredient in pet food.  Many countries have banned shark finning but still allow shark fishing to occur within their territorial waters. What is the difference between shark finning and shark fishing?

Shark finning is the removal and sale of shark fins, while the rest of the shark body is dumped at sea (the sharks are often still alive!). Shark fishing typically refers to the catch and harvest of the entire shark (or most of it), or the practice of catch and release in a recreational fishery.

Shark finning is a wasteful and cruel practice. It is wasteful because the entire body of the shark, which could provide a valuable source of protein as well as income, is dumped overboard at sea because the body would otherwise take up cargo space on the ship. In today’s markets, the fin alone is worth more than the rest of the shark. Shark finning is cruel because the fins are typically removed from live sharks, which are then thrown back into the ocean and left to drown. The impact of shark finning on the global shark population is dramatic and it has been cited as a major conservation concern. Globally, scientists and conservationists have reported a drastic decline in the abundance of assessed shark and ray species, with up to 30% of all species now classified as threatened or endangered. Limited data to assess how many and what type of sharks are being harvested results in a high level of uncertainty about the population status of many shark species. Shark finning contributes to this uncertainty because it is almost impossible to identify what species of shark has been caught based only on its fins.

The practice of shark finning has been a hot topic in the media, in Hollywood, and has been the focus of many organizations like Shark Savers and Shark Angels. But does that mean all shark fishing is bad? If shark populations can be managed to support sustainable shark fisheries, then there is a potential for economic and sustenance benefits, as well as achieving the goal of conserving sharks all over the world. Let’s take a look at some of the ways we can manage for healthy shark fisheries.

shark catch distribution

Canada and the Shark Fishing Industry

Canada banned the practice of shark finning in 1994, but sharks can still be fished for and harvested. The fishing regulations state that “When landed, the fins must not weigh more than 5% of the dressed weight of the shark.”  This means that while shark fishing is legal, shark finning is not. In Canada, it is legal to sell and purchase shark products, including shark fins. In fact, one of the first “certified sustainable” shark fisheries can be found on the coast of British Columbia (read about it here!).

The spiny dogfish shark is a coastal species captured on hook-and-line and are often captured as by-catch in ocean trawls. In B.C., the fishermen abide by conservatively small annual harvest quotas. They claim the number they remove each year is sustainable and not harming (over-exploiting) the population. The spiny dogfish is often used in fish and chips, sold as “rock salmon” in England, and their fins are also sold for use in shark fin soup. But, how sustainable is the fishery?  Scientists, the fisherman, and resource managers are monitoring the fishery carefully to find out. Spiny dogfish do not fully mature until they are 35 years old and females have a gestation (pregnancy) period of 2 years!  Spiny dogfish are long-lived and late maturing; these life history characteristics are typical of species that often become vulnerable to over-fishing.

Ok, so Canada seems to be managing its shark fishing industry (see the Federal governments Shark Management Plans – here!) but what about the rest of the world?  (I’m sure some of you might think differently; if so voice your opinions in the comments below!). Why are we always hearing about shark finning in the news? *** UPDATE – see Shannon Arnold’s comment below. Canada is not doing that well after all ****

International Shark Fishing Legislation

The European Union has legislation that requires fin weight to be less than 5% of the total weight of sharks landed. However, there is a loop-hole; the shark body is not required to be brought back to the harbour with the fins. Therefore, the fin to total body weight ratio is estimated at sea and may not  always be accurately recorded or monitored. Without the body of the shark – it is very difficult for enforcement officials at ship ports and harbours to estimate how much the fin weight actually relates to the unknown body weight! Scientists have denounced this regulation showing that it leads to gross species mis-identification as well as an underestimate of the number of sharks finned (Santana-Garcon et al. 2012*). Shark conservation organizations are working hard to close this loop-hole in the E.U. legislation.

You might now be asking – How do we conserve shark populations through sustainable fishing and yet stop the wasteful practice of shark finning?

Fins Naturally Attached


A policy initiative called “Fins Naturally Attached” is showing a lot of promise. Under this policy, shark fishermen would be required to leave the fin naturally attached to the body of the shark (or partially cut but still attached) after it is caught. This policy will drastically limit the number of sharks brought back to land for sale because the shark body will occupy space on the fishing vessel.  The policy will also allow resource managers to properly identify the shark species caught. Together, this means resource managers and scientists will have better data to set sustainable fishing quotas for many species of shark. Costa Rica was one of the first countries to adopt the fins naturally attached policy. Shark conservation organizations all over the world are pushing for fins naturally attached policies, including in the E.U. and New Zealand.

Here is what the Shark Trust has to say about the Fins Naturally Attached policy.

One of the biggest issues facing shark conservationists, scientists, and resource managers today is how to enforce new stricter shark fishing legislation on a global scale. Enforcement is a major issue and it raises two questions. First, how do we make sure all harvested sharks are reported, including those captured in one ocean and then sold on the other side of the world? Second, how can we be sure shark products exported to, and imported from, other countries were sustainably harvested? Costa Rica continues to battle such questions as it tries to conserve the shark species in its waters and enforce the fins naturally attached policy (see the article here!).

So what can we do to help conserve sharks? We can buy local, certified sustainable shark products (or don’t by them at all!). We can lobby with local conservation organizations to push our governments for stronger shark fishing legislations.  We can support organizations that provide education on the impact of shark finning. Education is our greatest tool; we can change the perception of sharks and promote sustainable shark fishing. A noticeable positive change in the public perception of sharks in recent years is a fantastic success and provides hope for future shark conservation goals (see our latest blog on the perception of sharks here!)

Do you think people should be fishing for sharks? Let us know in the comments below

Conservation Organizations: Spotlight on Canadian Marine and Freshwater Groups

By | Ocean Solutions | One Comment

There are so many volunteer, non-profit, and non-governmental organizations out there. Canada has plenty. Below is a short-list of key organization you may not have heard of, but provide outstanding opportunities to participate in conservation!

National Organizations


CIDA is operated by the Canadian federal government. Its mission is to lead Canada’s international effort to help people living in poverty. CIDA supports and provides resources to achieve meaningful, sustainable results and engage in policy development in Canada and integrenadarnationally to help our country, and others, reach development objectives. One of CIDA’s cross-cutting themes is to increase global environmental sustainability, which is integrated into all of its programs and policies. Not unsurprisingly, you may expect that CIDA supports projects promoting ocean and ocean resource conservation. And you are right! One example is Carriacou, a small island off the coast of Venezuela,  which is part of the tri-island nation of Grenada. In Carriacou, CIDA provided assistance to a small non-governmental organization KIDO Ecological Research Station, whose mission is to “To preserve the natural ecosystems, arts, heritage, and encourage sustainable development of the Southern Grenadines through environmental education, social development, scientific research and eco-tourism.”

CIDA supports Canadians who are looking to donate to worthwhile causes and volunteer or study abroad. Check out the website below to see how you can get involved! Want to participate? Click here!


Have you ever driven by a river in your city and seen a bunch of people on the riverbanks planting trees, or hammering logs into place? It may well have been volunteers with Trout Unlimited Canada (TUC). This organization began in 1972 in an effort to “conserve, protect and restore Canada’s freshwater ecosystems and their cold water resources for current and future generations”.  TUC uses a science based appryelloworadoach for restoration and conservation with the help of a dedicated staff and strong volunteer base. They operate in many cities in Canada and have large chapters in Alberta and Ontario. If you’re interested in pursuing a career in aquatic conservation this group is a great place to meet experts in the field! Many government and academic scientists are members and can often be found along the river bank directing and participating in events! One engaging and successful project is TUC’s Yellow Fish Road. Yellow Fish Road gives kids the opportunity to get involved in protecting their local rivers, streams, and lakeshores.

Now is the time to get to know your local TUC volunteer organizers so you can join the fun in the summer of 2013! Find your local chapter here and get involved today!


Project Seahorse is a non-profit science based marine conservation organization that operates out of the University of British Columbia. They are “committed to the conservation and sustainable use of the world’s coastal marine ecosystems. We generate cutting-edge research and turn our findings into highly effective conservation interventions. We collaborate with other researchers, governments, and local communities.” You may be thinking ‘Seahorses. They are neat… but it’s just one group of species. How does Project Seahorse promote overall ocean conservation?

Well, the organization attains broad conservation goals by studying the habitat (water quality as well as physical habitat) necessary for several threatened species of seahorses; the same habitat where many other species live. By understanding the habitat needs of seahorses and fighting for their protection, all of the animals and plants in that area also benefit, just like when a marine protected area focuses on shark conservation (see our blog on Sharks Saved in Marine Protected Area?).  Some of these other species may not get protection on their own because they are not known to be threatened or endangered.  Many species of seashores are found in the coastal waters of our oceans, an area in desperate need of protection, restoration, and commitment to sustainable development.

There are several ways you can get involved with Project Seahorse! Check out their page here!

Ontario Organizations


Do you live in the Greater Toronto Area (GTA)  of Ontario? Have you ever wanted to get out and clean up your local river or stream? Have you ever felt the need to plant vegetation along a barren river bank, or wanted to restore the in-water habitat in your favorite stream? Ontario Streams, a local non-governmental conservation organization, may be the volunteer opportunity you’ve been looking for.  Ontario Streams was established in 1995 and is dedicated to the conservation, rehabilitation and monitoring of streams and wetlands through education and community involvement. They are involved in the Atlantic Salmon Restoration project for Lake Ontario, several restoration projects in the watersheds of the GTA, invasive species monitoring, as well as participating in the program ‘Save the Redside Dace’ a threatened cold-water minnow species once abundant in the rivers and streams of the GTA.

If you’d like to get out and help restore and protect the rivers and streams in your backyard, connect with Ontario Streams today here!


Have you ever wanted to be a scientist? Now, with Citizen Scientist, you can! Imagine collecting fish, benthos (little invertebrates that live in the sediments of rivers, streams and lakes), and habitat data! You can also help enter and analyze the data. Citizen Scientists is a non-profit organization that monitors the aquatic community in the Rouge River watershed, in the GTA of Ontario. Citizen Scientistsci has been training volunteers in ecological monitoring since 2001. Leaders and volunteers follow the provincially standardized monitoring protocol for small streams, called the Ontario Streams Assessment Protocol (OSAP). Using a standardized protocol allows scientists to compare the data across years to see if there have been any changes. This is very useful when we want to see if our restoration efforts are improving the fish community and overall health of the stream.

If you want to try your hand at electrofishing to help monitor the fish community in a tributary stream of the Rouge, count salamanders in Rouge Park, or collect benthic bugs and identify them, Citizen Scientist is the organization for you! See how you can get involved here!

Seafood Choices: Harvard Changing The Way Students Eat Their Fish

By | Ocean News | One Comment

Universities, especially large schools like Harvard, have a lot of hungry minds and mouths to feed. The Harvard University Dining Services (HUDS) has risen to the challenge of making their operation more sustainable, from both an energy and food waste perspective. Now, HUDS is also offering sustainable seafood menu choices  in their campus food courts.

Previously, Harvard’s food courts offered meals of tuna, tilapia, shrimp and salmon among other tasty ocean creatures. Starting in the fall of 2012, after months of planning, sustainable dishes are being featured as alternatives for the fish foodies of Harvard. The dishes include as swai (a South Asian catfish), as well as mussels and shrimp caught nearby on the East Coast of Canada and the US.

What the HUDS has undertaken is no small task. Buying ‘sustainable’ seafood is not as easy as it sounds. Buyers need to consider so many variables that it can be difficult to find a truly sustainable meal. Some considerations include, buying wild or farmed fish; local species which may be in limited supply or international species where we don’t know the harvesting practices. And in some sad cases, you have no idea what you’re buying without performing a DNA analysis. All over the world threatened and endangered species are often sold under common fish names such as ‘cod’ or ‘catfish’. In Toronto and New York markets, research has shown that many fish species are mislabelled , making it nearly impossible for conscious shoppers to make a sustainable choice.

Fishing practices over the past two centuries as well as habitat degradation has decimated many of our fish stocks. While calling for a moratorium on all fish and seafood consumption is unrealistic, there are many actions we can each individually and collectively take to preserve what we have left in the oceans and promote its restoration. HUDS is developing guidelines for sustainable seafood that will help many large organizations adapt to similar practices in the future. This is the crux of the matter, since most sustainable eating guidelines are aimed at individuals and families, not a dining hall that may feed several thousands of people. However HUDS isn’t doing it alone. They are getting a lot of help from sustainable seafood advocate Barton Seaver who authored “For Cod and Country”. Together, they will monitor the success of the HUDS program and report their findings so that other large organizations can model similar programs based on HUDS’ success.

seafood watchWhile HUDS faces the daunting task of feeding thousands, most of us only have a few hungry mouths to feed. Happily, there are many places you can go for sustainable seafood guidance. One widely used source is produced by the Monterey Bay Aquarium’s SeaFood Watch. It helps seafoodies make the best sustainable choices for their meals. There is even an iPhone app!

Choosing to buy sustainable seafood whether it is sustainably harvested, farmed, or wild, can make a big difference in what ends up on all our plates at home and in our restaurants.  This is one Ocean Conservation action to which we can all contribute!

Will you use the Seafood Watch app now that you know you can make more sustainable seafood choices?

Plastic, plastic, everywhere. Even in the Great Lakes?

By | Ocean News | One Comment

Plastic. It’s in pretty much everything. There is almost no part of your day when you’re not using something made of, or containing plastic. But…we recycle? So, no big deal right? Wrong. It’s a huge deal. While scientists have known for years that the amount of plastic in the oceans is rising, it now looks like it is rising in the Great Lakes as well.

In the summer of 2012, researchers from the State University of New York (SUNY) sailed across the Great Lakes collecting water samples. They were looking to see how much plastic they would find. The researchers, led by Dr. Sherri Mason, found that in two of the 21 samples they collected the concentration levels of plastic was extremely high, greater than 600,000 plastic pieces per square kilometer. Other samples had a much lower concentrations of plastic, nearer 600 plastic pieces per square kilometer.

The researchers were shocked to find that the highest concentration of plastic they observed in the Great Lakes was greater than what has been reported from the Great Pacific Garbage Patch, which is found in a large gyre in the North Pacific Ocean. A gyre is a circular current in the ocean that causes debris to collect and get trapped at its center, where it accumulates.

While Dr. Mason’s research is preliminary and still needs to be processed through the rigorous process of peer-review; these initial findings are a cause for concern.

Plastics end up in our streams, lakes, and oceans due to improper disposal. Littering, as well as misplaced debris during garbage collection and other practices can lead to plastic ending up in our waters. The plastic we find in the water isn’t always a plastic bag, water bottle or toy. These plastics can break down into smaller pieces of microplastic that we may not easily see, but still pollute the water.

Plastic in our oceans and lakes may lead to several problems. Here are two examples:

1) Oceanic and freshwater species may eat the plastics. For example, sea turtles are known to eat floating plastic debris because they mistake it for food, potentially jelly fish. This can cause the sea turtle to become impacted and die.

2) Plastics tend to absorb toxins (PCB’s, DTD’s etc.) that could be transferred to any animal that eats the plastic, and then potentially humans.

So what can YOU do?

Read Speak Up For Blue’s tips on how to reduce your plastic use.

Help out our Great Lakes through volunteer beach and shoreline clean up’s. TD’s Great Canadian Shoreline Clean Up is a fun event and helps save our Great Lakes!

If you’re interested in learning more about plastic in the ocean the documentary “Addicted to Plastic” is an in-depth look the global plastic problem. This documentary has won numerous awards and is often featured at environmental film festivals all over the world.

What are you doing to reduce your single use plastic? Tell us in the comments below!

Check Out the Trailer Below!!!

Sharks saved in Marine Protected Areas?

By | Ocean News | 2 Comments

A recent research study by Knip and fellow researchers (2012) published in the journal Biological Conservation, evaluated a Marine Protected Area (MPA) for the conservation two species of coastal sharks. The scientists studied the movement patterns of the sharks and determined how much time they spent in the recently established MPA, the Great Barrier Marine Park in Australia. Before I discuss their results with you, we should go over some basic background information.

What is a Marine Protected Area?

A Marine Protected Area (MPA) is an area of ocean or coastline where human activities are restricted. The restrictions in an individual MPA may vary with the specific goals and objectives of that particular MPA. For instance, some MPA’s restrict all human activities, including tourism. This type of MPA can be called a “sanctuary” or a “reserve”. Other MPA’s may only limit fishing and exploitation during a specific season or for a certain species. Most often, MPAs are created to ensure the conservation of some or all species, habitat, and/or resources within them.

In 2010, the International Union on the Conservation of Nature (IUCN) estimated that there are roughly 5880 MPA’s, covering nearly 1.2% of the world’s oceans. This is an increase of over 150% since 2003.

A common criticism of new MPAs is that they are implemented with little prior knowledge of how well they will protect habitat or species in the given area. This is because within one MPA there can be many habitat types, from lagoon and coral reefs, to the open ocean. Managing all of these habitat types and the species that live within them can be a daunting task. Also, it can be hard to estimate how effective the MPA is for the conservation of a specific species, or groups of species such as sharks. What measure scientists use to estimate effectiveness is also important. Should effectiveness be based on the amount of time a species spends in the MPA, much much area of the total MPA they use, or some other measure? What is important to remember is that any protection is better than nothing and all MPA’s provide some amount of conservation protection.

To successfully manage a MPA, partnerships and collaboration between local citizens who use the resource and conservation groups, the government, and sometimes private businesses are needed. Who is involved really depends on the goal of the MPA.

Sharks are a mobile species. What does that mean?

Many shark species use a lot of different habitats throughout their life. Some are born in shallow coastal areas but leave once they grow up. For example, lemon sharks are born in shallow lagoons often near mangrove forests. When the sharks reach 2 to 3 years old they will venture out into the larger coastal zones of the ocean. We call these species mobile because they travel between many different habitats. There are some sharks though, like the spottail in the study we’re going to talk about, that stay close to shore for their entire lives.

Sharks and MPA’s

Most of the research on the effectiveness of a MPA has been based on sedentary species. That is, species that don’t move around a lot, such as a clam. So, we could protect a clam and their habitat relatively easily by putting a small MPA around the habitat they live in.

Planning and managing a MPA for sharks is complicated. In order to maximize the benefit of the MPA to a shark species we need to know what type of shark we are trying to conserve, are they more or less mobile, what life stage will use the MPA, and so on. Through their research, discussed below, the scientists asked this type of question: Does a new MPA within the Great Barrier Reef Marine Park offer conservation benefits for two species of sharks, the pigeye and spottail?

What does the research show?

Knip and fellow researchers looked at whether a MPA on the Great Barrier Reef in Australia was beneficial for two kinds of sharks, the pigeye and spottail. The pigeye is a large shark that only uses the coastal area as a juvenile and the spottail is a medium sized shark and stays in the coastal area for its entire life. Both sharks are known to use the coastal area where the new MPA was established. Fishing is restricted (but not forbidden) in the MPA, so the sharks are able to reproduce and grow up to a reasonable size before they must face the big ocean, and potentially more fishermen.

The researchers tagged sharks and tracked their movements to see how often they used the MPA. Based on how much time the sharks spent in the MPA the researchers could say if the MPA offered a conservation benefit to them. The researchers found that both of the sharks DO use the MPA and even though the pigeye leaves and comes back, it is likely offering a conservation benefit by having the MPA as a refuge. They also found that the pigeye sharks usually left and entered the MPA at the same ‘exit points’. Like taking the same path through a forest each time you’re out for a hike. This kind of information can be very helpful for MPA managers because they might be able to provide enhanced protection in high use areas.

Conservation managers can use the results of studies like this of to help improve existing MPAs and plan new MPA’s that are more effective to help shark conservation.

How to you TRACK a shark?

By now you’re probably asking: HOW do you track a shark?! It takes a lot of work, but it can be very fun! While volunteering with the Bimini Biological Field Station in 2003, I participated in a study that was looking at the movement patterns of young lemon sharks. We used a tracking method similar to the study by Knip and others. First of all, you have to catch the shark. We used nets, while Knip and fellow researchers used baited hooks to capture the sharks, but neither method harms the sharks. Once captured an ‘acoustic tag’ is attached to the shark which sends out a pulsing beep in a particular sequence, say 2-3-2, that a special kind of receiver (underwater computer) can hear. Once the shark is released, anytime it comes within a certain distance from the receiver, the shark is recorded as being nearby. We call this passive tracking because receivers are placed at several places and we hope the shark swims by. Tags that send data to satellites in real time are also very popular for passive tracking.

Here are some resources if you’re interested in learning more about MPA’s

Global Ocean Protection: Present Status and Future PIUCNossibilities. 2010-11-23.

An area of Bimini, Bahamas was declared a marine protected area in 2008. Follow the MPA development here:

Search MPA global database for MPA’s near you. There may be volunteer opportunities near by!

Ocean Fertilization: What’s a little bit of iron sulphate to a big ocean?

By | Ocean News | 8 Comments

In October, conservation groups, scientists, and the Canadian public were surprised to learn that an ‘ocean fertilization’ experiment had been completed off the coast of British Columbia in July. It made national and international news; sparking debate, anger, and frustration among scientists and the public.

So, what’s the big deal?

The Haida Salmon Restoration Corporation performed what they referred to as a ‘salmon restoration project’. The project involved dumping nearly 100 tonnes of iron sulphate into the ocean off the coast of B.C., claiming it would benefit the local salmon population. Although critics have said the project was really a geoengineering scheme aimed at selling carbon credits.

What is ‘Ocean Fertilization’?

Ocean fertilization is the process of adding limiting nutrients or elements to the ocean in order to promote the growth of microscopic plants, called phytoplankton. Think of it as fertilizing your lawn. By adding nitrogen to your lawn you give the grass what the soil did not have enough of. In the ocean, iron sulphate is often a limiting element that controls the amount phytoplankton that can grow. When we add iron to the water, phytoplankton have been shown to ‘bloom’, that is, they reproduce…a lot!

What does Ocean Fertilization have to do with Climate Change?

In the 1980s John Martin decided to re-investigate an old idea; if we add limiting elements and nutrients to the oceans, can we increase productivity? Basically, the idea was that if you add iron sulphate to the ocean it will promote phytoplankton blooms. Because phytoplankton are plants, they use the carbon dioxide from the air to make oxygen, just like trees. It has been proposed that phytoplankton in these large ‘fertilized’ blooms could help global climate change by removing carbon dioxide from the atmosphere. The amount of carbon dioxide (and other greenhouse gases) in the atmosphere is a leading cause of climate change.

Why is Ocean Fertilization not a great idea?

You may be asking; “if we can remove carbon from the atmosphere and help local salmon populations, why have scientists, along with the United Nations and other conservation organizations (including World Wildlife Fund) said ‘No’ to ocean fertilization?” What’s the problem?
Here’s a brief list:

  • A recent research study showed that “up to half” of the plankton bloom may die and sink to the ocean bottom, taking the carbon with them. We don’t know what happens to the other half of that plankton bloom.
  • The ocean bottom is not always barren. It can provide important habitat for many organisms, including deep sea corals, juvenile fish, crabs, lobster, and other bottom dwelling animals. This is especially true closer to shore. The home of these bottom dwelling creatures may be impacted by the dying phytoplankton. Bacteria living on the ocean floor use oxygen from the water as they digest the phytoplankton that have rained down on them. This can create an oxygen ‘dead zone’. Dead zones can lead to fish kills as well as harm many of the creatures that live on the ocean floor.
  • The cost effectiveness of ocean fertilization is very low. It costs a lot of money to get all of the necessary material out to sea, because a large amount of iron must be added to see any change in phytoplankton abundance.
  • Some research shows that methane and nitrous oxide may be released back into the atmosphere when some of the phytoplankton die. You guessed it, those gases also influence climate change!
  • All life in the ocean is connected. We call this the food web. If you add a lot of biomass to the bottom of the food web there may be untold implications for every rung on the web. What’s not clear is, how much bottom biomass is too much? What species would benefit, or be harmed? How long will a single phytoplankton bloom influence the local food web? Scientists are still looking for answers to these questions.

Overall, the scientific community has been clear: right now, the risk of ocean fertilization far outweighs the benefits. All signatory countries of the UN convention on biological diversity, including Canada, voluntarily agreed to NOT participate in ocean fertilization. What is not clear, however, is how involved was the Canadian government in this project? Why was no action taken to stop the ‘non-experiment’? Did the project really occur outside of Canada’s 200-mile territory? We’ll be waiting to see if the enforcement branch of Environment Canada takes action to find out answers to these important questions. Unfortunately, all we can do now is wait to see if the world’s largest ocean fertilization ‘experiment’ has any effect on carbon sequestration, salmon rehabilitation, or the larger food web.

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