Chapter 9 Review Questions

F (see “Oceanic Ecosystems”)

F (see “Fisheries”)

T (see “Energy”)

T (see “Fisheries”, Box 9.3)

F (see “The Nature of the Collapse”)

F (see “Fisheries”)

T (see “Indigenous Use of Marine Resources”, Box 9.6)

T (see “Aquaculture”)

F (see “Oceanic Ecosystems”)

F (see “Lessons”)

The Agreement covers an area of 2.8 million km² occupying international waters more than 200 nautical miles (370 kilometres) off any coastline and prevents commercial fishing in high seas areas for at least 16 years after entry into force. The Agreement also requires signatories to provide resources for research and monitoring to better understand the Arctic marine ecosystem. This marks the first time an agreement has been reached prior to fishing taking place. The Agreement is pre-emptive, uses a precautionary principle approach, and incorporates Indigenous perspectives.

Oceans are key components in global cycles and energy flows. Marine ecosystems are home to a vast array of organisms displaying greater diversity of taxonomic groups than their terrestrial counterparts. Marine organisms help feed us, and they are also the source of many valuable medicinal products. We use the seas to dump our waste products and to transport most of our goods around the world. The oceans also enrich our cultures.
(see “Oceanic Ecosystems”)

Found throughout tropical and subtropical seas, they are among the most diverse and productive ecosystems on Earth. Like the rainforests, they have an ancient evolutionary history, having first appeared more than 225 million years ago, with some living reefs perhaps as old as 2.5 million years. With solar radiation the primary source of energy, these habitats are found predominantly within 30° north and south of the equator.
(see “Oceanic Ecosystems”, Box 9.1)

The ocean surface takes up carbon by gas exchange, driven by wind exchange and imbalances between the amount of carbon in the atmosphere and in the oceans. Marine primary producers get their carbon from the dissolved CO₂ in the water as bicarbonate. There is a balance between the amount of CO₂ in the atmosphere and bicarbonate in the water. If there is too much in either compartment, a gradient is created, and the carbon migrates along the gradient between the ocean’s surface and the atmosphere. Carbon also is continuously being moved out of the surface layers of the ocean into deeper water, where it is stored in dead organisms, ocean sediments, and coral reefs. The more that is stored at depth, the greater will be the gradient pulling carbon out of the atmosphere and into surface waters to compensate for these losses.

Excess carbon dioxide in the atmosphere is absorbed by oceans and produces carbonic acid, making the oceans more acidic. If CO₂ emissions continue to rise at current rates, upper-ocean pH will decrease to levels lower than have been experienced for about 300 million years. Scientists predict that by the end of the century, nowhere on Earth will water chemistry still permit the growth of coral reefs. Their calcium skeleton will simply be melted away by the increased acidity, and the concentration of available carbonate ions will be too low for marine calcifiers, such as coral reefs, molluscs, crustaceans, and some algae, to build their shells and skeletons.

(see “Oceanic Ecosystems”)

Ocean waters are not uniform in temperature. There is usually a sharp transition in temperature between the warmer surface waters and the cooler waters underneath. This is known as the thermocline and generally occurs at a depth of 120 to 240 metres, depending on latitude and ocean currents. Water also is warmer nearer to the equator and coolest near the poles.

Water moves around the globe as a result of differing densities in a process called thermohaline circulation. The high salt content of sea water allows water density to increase before it freezes, and then sinks, at certain sites such as the North Atlantic, the Arctic Ocean, and the Weddell Sea in the Antarctic. This sinking is the main mechanism for removal of atmospheric carbon by the oceans. Cold water that has sunk moves along the sea floor until it mixes with surface waters and is transported back by wind-driven currents to the conversion areas. This results in a global system of currents that mediate Earth’s climate through transport of heat and water.

(see “Oceanic Ecosystems”)

Having good baseline data is important when trying to assess change. In fisheries, scientists have tended to look only at the most recent data rather than comparing them with historical catches. This problem is known as a shifting baseline, in which scientists have no other option than to take the current degraded state as the baseline rather than the historical ecological abundance. The lack of good baseline data for global fish populations led to overestimates of abundance that contributed to declines in fish stocks.

As target fish stocks decline, commercial fishing fleets first increase their efforts towards the target species and then turn to the next most profitable species until that, too, is depleted. Then they pursue the next most profitable species and so on. This is a familiar foraging behaviour in ecology, known as prey switching. In commercial fisheries it leads to serial depletion, in which one stock after another becomes progressively depleted even if the total catch remains the same.

A shift in target species is not the only change; we are also progressively exploiting lower and lower trophic levels as larger, more desirable fish decline. Some fisheries now focus on invertebrates like Atlantic crab. Large-sized fish no longer exist. This is known as fishing down the food chain.

(see “Fisheries”)

In longline fishing, long fishing lines strung with large hooks are baited and set to catch fish in both shallow and deep waters Longline fishing kills 40,000 sea turtles each year, along with 300,000 seabirds and millions of sharks. Bycatch of albatross, petrels, and shearwaters in longline fisheries is one of the greatest threats to these seabirds.

In bottom trawling, heavy nets are dragged along the sea floor, scooping up everything in their path, including organisms that provide key habitat and food, such as sponges and corals. This leads to secondary food chain effects. It is commonly used for shrimp, but is very inefficient, with only 10 per cent of the catch being shrimp and the rest bycatch. It is also used for groundfish. It is one of the most destructive fishing methods; it is as damaging to the seabed as all other fishing gear combined.

Bycatch is where harvested biomass is discarded and dumped because it is not the right species or size.

(see “Fisheries”)

Chemical pollutants take two main forms: toxic materials and nutrients. Many are toxic materials that are harmful to life and may cause instant death if released in sufficient quantity, or have sub-lethal effects such as inhibition of reproduction. Chemicals are also subject to bioconcentration, particularly along the boundaries of atmosphere and ocean, or seabed and water.

Many chemicals in everyday use have been found to mimic endocrine processes that control bodily processes such as sex, metabolism and growth. These are known as endocrine disruptors and are found in commonly used products such as soaps and detergents. The major effect of these chemicals on marine life detected so far is the feminization of various aquatic species.

Nutrient enrichment in oceans leads to oxygen depletion and the development of large dead areas within the oceans. These dead zones lack sufficient oxygen to sustain most sea life, and hypoxia also promotes development of far more male fish than females, which may lead to extinction. Individuals that can escape dead zones often become more vulnerable to predation, and have a reduced ability to find mates. Global warming will exacerbate the growth of dead zones because warmer water holds less oxygen.

Plastics are now found throughout the oceans. Plastic ingestion can lead to direct death of seabirds and fish, and to other effects such as loss of appetite, stunted growth, and exposure to pollutants that leach out of the plastic.

(see “Pollution”)

Following the wreck of the Exxon Valdez off Alaska, for example, more than 750 sea otters were killed. Long-term effects of the spill were even greater due to such ongoing impacts as contaminated food chains. Importantly, the Pacific herring, considered an important keystone species in the affected ecosystem, was still listed as “not recovering” more than 25 years after the spill. Oil is lethal to marine life in its physical effects and its chemical composition. Cleanup attempts following oil spills can also damage many species. This example highlights the long-term consequences of oil spill pollution in marine environment. (see “Energy”)

Climate change will have many effects on marine ecosystems, and because of our lack of understanding of these systems, the impacts are not easy to predict. Two main expected changes include:

• Rising sea levels due to thermal expansion of water and melting of land-based glaciers, which will lead to increased storm impacts, degradation of coastal habitats, alteration of tidal ranges, flooding, changes in sediment and nutrient patterns. Rising levels could displace approximately 1 billion people, many of them among the poorest in the world.
• Increasing sea surface temperature which could cause global destruction of coral reefs, lead to ice break-up, and may shut down or slow thermohaline circulation which in turn would cause widespread climate change, movement of fisheries, and risk of deep-sea hypoxia.
  (see “Climate Change”)

Marine protected areas are underwater reserves that are designated as protected from human activities due to their special values. Marine reserves

• conserve both fisheries and biodiversity;
• protect resident species;
• provide a critical benchmark for the evaluation of threats to ocean communities;
• are required in networks for long-term fishery and conservation benefits; and
• are a central management tool supported by existing scientific information.
  (see “Marine Protected Areas”)

Coastal and marine resource management is typically fragmented and often ineffective in Canada due to the size of Canada’s coastal zone, and length of our shorelines, but also because jurisdiction is split between federal and provincial governments, and influenced by municipal management. This overlap often leads to conflict in priorities and actions.

(see “Canada’s Motto”)

Some reasons for the collapse:

• Foreign overfishing
• Domestic overfishing
• Imperfect science and management
• Inappropriate incentives for processing plants and fish workers
• Changing environmental conditions
• Predators
  (see “Some Reasons for the Collapse”)

Key aspects of the changes related to Indigenous peoples include:

• Increased opportunities for Indigenous participation. The changes allow the minister to enter into agreements and cooperation with Indigenous peoples to further the goals of the Act. These agreements may provide for the application of Indigenous laws and Indigenous administration and enforcement within their own territories. However, the federal government is not required to enter into these agreements.
• Consultation requirements. The revised language in the Act aligns with requirements that the government consult with Indigenous peoples and consider any adverse impacts that a decision may have on the rights of Indigenous peoples. However, there is no requirement to gain consent of Indigenous peoples.
• Consideration of traditional knowledge. While the changes do not require the minister to consider traditional knowledge, the Act provides for the consideration of traditional knowledge with respect to decision-making.
• Enhancing Indigenous partnering opportunities. Not explicitly outlined in the changes to the Act, the federal government has proposed a modernized fish habitat protection program to provide enhanced and meaningful opportunities for Indigenous communities to be involved.
  (see “Indigenous Use of Marine Resources”)

Salmon are anadromous, living in both salt and freshwater, and they depend on a wide range of conditions that link the mountains to the sea. If any of these myriad factors go awry, then higher mortality rates can drastically reduce the numbers of fish returning to spawn in subsequent years. These factors are the links in a chain reflecting the limiting factor. It also means that salmon are good indicators of the overall health of our environment and our resource management practices.

(see “Indigenous Use of Marine Resources”, Box 9.5)

The main sources of marine toxic pollution in Canada originate with the deposition of airborne pollutants from fossil-fuel combustion, agricultural runoff, inadequately treated sewage, and by-products or waste materials from refining processes (e.g., effluent from pulp and paper mills).

(see “Pollution”)

Salmon farming provides economic opportunities that can be lifesavers for some remote communities, especially Indigenous communities. Nonetheless, serious concerns exist about aquaculture:

• Escapement: species being farmed may escape and become invasive species, such as Atlantic Salmon being farmed in BC
• Disease: high stocking levels in aquaculture make farmed species susceptible to disease, and disease can easily spread to wild population nearby
• Lice: strong scientific evidence indicates that pink salmon smolts (salmon changing from a freshwater to a saltwater environment) in certain areas of the coast are being weakened by excessive sea lice coming from farms near their migration routes
• Pollution: antibiotics used to fight disease in farmed population can harm marine life as they are released directly into the ocean, as are excess food and feces, which act as organic pollution and deplete oxygen on the sea floor, release noxious gases, and smother benthic organisms
• Predator control: aquaculture farmers routinely shoot predators such as seals and sea lions, and these shooting are likely under-reported
• Energetics: farmed fish, and salmon in particular, are usually fed other fish, which is energetically wasteful and leads to depletion of other fish stocks
• Social dimensions: most aquaculture profits go to multinational corporations, and do not provide substantial benefits to local economies. At the same time, mechanization has led to lost jobs, and the negative impacts of farmed fish on wild populations reduces the ability of local people to rely on them
• Human health: farmed fish, including salmon, are often fed artificial colouring to give them a desirable pink hue. Some common colourants such as canthaxanthin, cause retinal damage.
• Genetic modification: The first genetically engineered animal approved for sale in Canada in 2016 was Atlantic salmon
  (see “Aquaculture”)

Marine protected areas (MPAs): established by the Department for Fisheries and Oceans (DFO) under authority of the Oceans Act. Their purpose is to conserve commercial and non-commercial fisheries, protect species at risk, and conserve unique habitats—i.e., areas of high biodiversity or biological productivity.

National Marine Conservation Areas (NMCAs): developed by Parks Canada under the Canada National Marine Conservation Areas Act. These areas differ from national parks in that they are managed for sustainable use and not necessarily for the protection of ecological integrity.

Other effective area-based conservation measures (OECMs): comprises the most significant amount of protected areas announced by the Canadian government in 2017. They are outside formal government protected area systems and were designed to allow inclusion of areas such as tribal parks that also have a strong biodiversity mandate but heretofore have not been included in global calculations.

Wildlife areas and sanctuaries: through the Canadian Wildlife Service (CWS), Environment and Climate Change Canada has several programs that may include designation of marine sanctuaries such as national wildlife areas and migratory bird sanctuaries.

National parks: Finally, Canada has established 46 national parks managed by Parks Canada under authority of the National Parks Act. Although not specifically for marine areas, approximately one-half border one of the oceans or Great Lakes and have the potential to exert strong protective powers.
(see “Ocean Protection Strategies in Canada”)

The collapse of the Atlantic groundfish fishery highlights how some contemporary resource management practices may encourage resource liquidation. In theory, fisheries managers around the world and in Canada seek to manage the fishery according to three priority considerations: ecological sustainability, economic goals, and social outcomes. In reality, these goals are often in conflict, at least in the short term, and the second goal often becomes paramount because of political interference.

The case study illustrates that fisheries management requires scientific understanding of the biophysical resource system, a greater appreciation of traditional or local ecological knowledge, and parallel understandings of the history, culture, economy, and politics of the region, as well as federal and provincial fisheries and regional development policies. It demonstrates conflict among different values and interests (as discussed in Chapter 6) and the manner in which conditions can change dramatically over a relatively short time. The Atlantic fishery also provides an excellent example of how inexact science often is and the extent to which complexity and uncertainty dominate.

(see “Lessons”)

Three principles to guide all ocean management decision-making:

• Sustainable development “recognizes the need for integration of social, economic, and environmental aspects of decision-making and that any current and future ocean resource development must be carefully undertaken without compromising the ability of future generations of Canadians to meet their needs.”
• Integrated management “is a commitment to planning and managing human activities in a comprehensive manner while considering all factors necessary for the conservation and sustainable use of marine resources and shared use of ocean spaces.”
• The precautionary approach is defined in the Oceans Act as “erring on the side of caution.”
  (see “Canada’s Oceans Strategy”)