How do Marine Ecosystems Serve Society

Question 1

What are the different types of Shrimp farming?

Answer 1

• Extensive: Large ponds which rely on natural productivity, native species with no feeds. Yields less than 500 kg/ha/yr
• Semi-intensive: Large ponds with hatcheries attached. No longer deriving larvae from the wild but instead hatcheries; caught in the wild, striped of their eggs and allowed to hatch in a captive environment. Fertilisers and feeds used. Yields above 500 kg/ha/yr
• Intensive farming: Smaller ponds, 5th of a ha. High water turnover, avoiding stratification of the water column and anoxic conditions forming. Major management - eliminating predators, antibiotic (density problems). 5000kg / ha /yr
• Super-intensive farming: independent of environment, high density, water circulation, zero effluent (eliminated the sludge forming at the bottom), closed life-cycle, all in-house. Tapping into natural lifecycle. Eggs from farm itself.

Question 2

Tony paper - inputs to shrimp aquaculture

Answer 2

Larsson J et al. 1994. Environmental Management 18: 663-676

• Find out what the basis of the shrimp productions actually were. Contributing to that they have looked at four different things, the marine ecosystem (natural marine ecosystems in the surrounding areas), inputs from agriculture, source of post larvae and nature of pond ecosystem itself.
• Shrimp production requires:
  
  • mangrove as natural source of postlarvae
  • food - pellets (70% diet) from marine and agricultural systems
  • food from mangrove detritus (30% diet)
  • clean water, solely (here) from mangrove lagoons. Using a pump or the tides.
  • sequestration of CO2 from industrial inputs (fuel, manufacturing)
  • EF = 36.8-188.9 ha mangrove per ha of prawn pond. (every hectare of shrimp pond 36 - 189 of mangrove and mangrove lined lagoon is needed to support its production. Providing a ecosystem service to support the shrimp farming.
• They calculated these different contribution to the shrimp farm production. (figure in notes)

Question 3

Benefits of shrimp farming

Answer 3

Positive

• Financial: profitable
• Economic: employment, good returns on investment risk
• Meet shrimp demand: capture fishery has peaked
• Farmed prawn production increased 10-fold 1982-94

Question 4

Issues with shrimp farming - Tony paper

Answer 4

Alongi DM 2002 Environmental Conservation 29: 331-349

Indonesian study, related shrimp catch to mangrove area in the province.

Positive correlation tidal wetland/mangrove area and catch notably some species of prawns (e.g. banana prawn, not tiger prawn)

Correlation could be due to another factor, is the mangrove area varying due to another reason?

Linkages between mangroves and capture fisheries include

• ‘nursery’ role (e.g. physical habitat acts as refuge for juveniles vulnerable to predation)
• ‘productivity’ role (e.g. habitat productive of food for developing juvenile)
• Productivity role localised (stable isotope data)
• • First production failures in Taiwan and China in 1988
• Many viruses: white spot (Asia), Taura (S America)
• 76% of N, 87% of P retained in sediments, too much can cause harmful algal blooms
• Stalinisation of groundwater, as farms have moved inshore adversely impacting agriculture
• Increased sedimentation and turbidity, chemical treatments
• Antibiotics being released
• Natural circulation impeded, keeping productivity inshore
• Acidic soils, in these environments which traditionally are dominated by mangroves you have a significant input of organic matter. This means that the oxygen in the water is used up, anoxic conditions form and sulphur becomes sulphide. When converted to shrimp ponds the sulphide is exposed away from anoxic conditions and becomes sulphate, acidifying things.
• Loss of mangrove, replacing the mangrove which is supporting the shrimp farm as an ecosystem process.

Question 5

WIDER READING: aquaculture - diminishing mangrove

Answer 5

Guimarães et al., 2010- Impact of aquaculture on mangroves

The study:

Contribution of aquaculture in the diminishing of mangrove areas along the northern coast of the State of Pernambuco (northeast Brazil) over the last 30 years.

The results:

Area and spatial distribution varied considerably over the last 30 years

Inadequate laws and lack of legislation caused a reduction of 255 ha of mangrove between (1999-2001) due to aquaculture and tourism

2052 ha of mangroves lost between 1973-2005

Of this reduction only 9.6% used for conversion for nurseries for aquaculture

Question 6

What does ecosystem services mean?

Answer 6

Loss of these ecosystems means loss of the benefits they bring (mostly at no or little cost) to society

Ecosystem services ‘benefits [and occasional disbenefits human populations derive, directly or indirectly, from ecosystem functions’

Question 7

Give some types of ecosystem services

Answer 7

• provisioning
• regulating
• cultural
• Supporting
• Food - all food products derived from plants, animals, and microbes.
• Fibre - wood, jute, cotton, hemp, silk, and wool.
• Fuel - wood, dung, and other biological sources of energy.
• Genetic resources - genes and genetic information used for animal and plant breeding and biotechnology
• Biochemicals, natural medicines, and pharmaceuticals - e.g. alginates
• Ornamental resources - e.g. skins, shells, flowers used as ornaments
• Fresh water - drinking, washing, energy etc

Question 8

Regulating ecosystem services

Answer 8

• Air quality regulation - chemicals influencing atmospheric composition
• Climate regulation - local (e.g. changes in land cover affecting temperature and precipitation) and global (e.g. greenhouse gases)
• Water regulation – e.g. runoff, flooding, and aquifer recharge influenced by land cover such as by conversion of wetlands or forests
• Erosion regulation – e.g. vegetation retains soil, prevents landslides
• Water purification and waste treatment – e.g. natural sources of impurities, filtering of organic wastes, assimilation and detoxification of compounds through soil and subsoil processes
• Disease regulation – influence on abundance of human pathogens (e.g. cholera) and disease vectors (e.g. mosquitoes)
• Pest regulation - effects on crop and livestock pests and disease prevalence
• Pollination - impacts on pollinators
• Natural hazard regulation – e.g. mangroves and coral reefs reduce hurricane damage
  *

Question 9

Cultural services: non-material benefits

Answer 9

• Cultural diversity - influences on diversity of cultures
• Spirituality and religion – influences of ecosystems or their components
• Knowledge systems - both traditional and formal
• Education - basis for both formal and informal education
• Inspiration - e.g. of art, folklore, national symbols, architecture and advertising
• Aesthetics - e.g. values reflected in the support for parks, selection of housing locations
• Social relations - e.g. fishing societies vs nomadic herding or agricultural societies
• ‘Sense of place’ - associated with recognized features of their environment
• Cultural heritage – e.g. historically important landscapes, culturally significant species
• Recreation and ecotourism – e.g. leisure based in part on natural or cultivated landscapes

Question 10

Supporting services: necessary for production of all other ecosystem services, fundamental properties and processes in systems like photosynthesis.

Answer 10

• Soil formation – influence of soil formation
• Photosynthesis – O2 production essential for most living organisms.
• Primary production - assimilation or accumulation of energy and nutrients by organisms
• Nutrient cycling – cycling and maintenance at different levels of ca. 20 nutrients essential for life
• Water cycling – fluxes of water essential for other organisms and processes
• Impacts on people often indirect or chronic

Question 11

WIDER READING: mangrove goods and services

Answer 11

Ewel et al., 1998- Different types of mangroves provide different goods and services

The study:

• Classification of mangrove forests and to identify which goods and services are likely to come from which kinds of forests

The results:

• Fringe mangroves- Primarily important for shoreline protection- removal can cause soil erosion and sediment deposition
• Basin mangroves- Important sources of wood, serve as natural sink (lack of water turnover leads to high levels of Nitrogen because of denitrification in anaerobic habitat) for both natural and anthropogenically enhanced ecosystem processes
• Riverine mangroves- Most productive, important to animal and plant productivity, could be due to high nutrient levels due to sediment trapping (Can be used to prevent excess sediment e.g. from construction of roads from being washed offshore to seagrass beds and coral reefs)

Question 12

How do you measure ecosystem services?

Answer 12

Direct use:

• can be easy e.g. knowing volume of good and market price, can estimate value

Indirect use:

• tends to be more difficult e.g. coastal protection ES knowing what it would cost to replace that ES for example man-made coastal protection structures or e.g. money spent to enjoy good or ES through tourism

Bequest and existence values:

• more intangible still e.g. surveys of people’s willingness to pay for knowledge that ecosystem (or rare species?) exists. (what would you be willing to donate to a charity ensuring that sea cows exist along a coastline?)

Question 13

Tony paper - monetary value on ecosystem services

Answer 13

• An example (Indonesia) of looking at the impacts of different types of activities on coral reefs. Gains to individuals (US$ 000s per km2) of various threats to coral reefs (benefits per stakeholder in brackets)
• Comparisons of gains to individuals (US$ 000s per km2) with those to society of various threats to coral reefs (benefits per stakeholder in brackets). Losses from protection, mining, fishing tourism ect. Compare net benefits to net losses.

Question 14

Coral reef management in Indonesia raises important societal issues

Answer 14

• Fishermen gain from reef blasting, but this may adversely affect other sectors (e.g. tourism)
• Should poor fishermen lose out (e.g. gear bans, MPAs) to accommodate overall societal benefits
• What are the cultural implications (e.g. sea gypsies in Indonesia)
• Sustainable financing of measures such as MPAs

Question 15

Summary

How do marine ecosystems serve society?

Answer 15

Mangroves and coral reefs provide excellent examples of how ecosystems generate goods and services, which benefit society

Yet these ecosystems are subject to multiple sources of degradation: e.g. shrimp farming (mangroves), ocean acidification, fishing effects, nutrient loading (coral reefs)

Valuing ecosystem services helps accounting for benefits of conservation against costs of degradation

Question 16

WIDER READING: Economic impacts caused by coral reef destruction

Answer 16

White et al., 2000 - Economic impacts caused by coral reef destruction

The study:

• Approximate economic losses being incurred from the destruction of coral reefs as well as the potential economic gains from reef management

The results:

• Healthy coral reefs can produce, on a sustainable basis, 20 t or more of fish and other edible products km2/yr ; once destroyed by use of dynamite or cyanide for fishing, production is reduced to less than 4 t/km2/yr
• The potential and real losses to the Philippines alone as coral reefs are destroyed are already more than US$ 1 billion/yr.
• Apo island, 1km 2 protected. The initial US$ 75 000 investment now annually returns between US$ 31 900 and 113 000 in the form of fish catch and island-based tourism revenues.

Question 17

Whta is the theory behind MPA’s?

Answer 17

Example of how things are expected to happen with an MPA with respect to fish. By reducing impact in MPA, mortality on target species is reduce and abundance increases. More animals will reproduce and support the wider population. In theory this creates a recruitment effect, and can also create a spill over effect if there is a net movement of individuals out of the MPA. There is almost no evidence for a larval recruitment effect.

(Measuring a larval spill over effect can be difficult as you need measurements of fluxes of individuals in and out of the reserve. This could be density dependent, providing motivation to move out of the reserve.)

Question 18

Well know because they form classic studies of the impact of marine protected areas on fish and coral reef ecosystems.

Apo and Sumilon are small island in the central Philippines.

Nick paper

Answer 18

Russ GR et al. 2005 Marine Ecology Progress Series 292: 1-12

Habitat structural complexity data, whether the habitat complexity is changing over time - as this may affect the abundances of species they are looking at. Very little change observed. Conclusion habitat has remained roughly the same.

Apo Island of the coast of Negros. A large community of people living there.

Sumilon, of the Southern tip of Cebu. Uninhabited, watched over by a coastguard.

Taken the biomass data, derived from underwater visual census work. The biomass of these target species has increased significantly, and something similar has played out in the others.

At Sumilon, abundances of large predatory fish have declined, increased and fallen again with cycles of protection. This is because the protection actually broke down and was brought in again.

At Apo, abundances of large predatory fish have steadily increased, this is because the protection hasn’t broken down.

(Figures in notes)

Question 19

Nick paper dissapointment

Answer 19

Used survey data to create a disappointment ranks. Ranked what people wanted to see and took it away from the rank of what people actually saw. All the things that came up in the top 5 disappointment rank, such as large animals which are the sort of things that study’s show are being increased by marine protected areas, showing that they are effective.

Question 20

Nick paper things other then MPA’s

Answer 20

MacNeil MA et al. 2015 Nature 520: 341-344

Put together global data across a whole range of countries. Looking at the trajectory of different species and of all fish biomass combined. Argues MPAs provide opportunity for recovery. Emphasises a significant level of recovery that also goes on where you do other things to manage the system, gear, species restrictions. Positive message not to just concentrate on MPAs.

Question 21

Nick paper limits to scientfici understanding

Answer 21

Sale PF et al. 2005 Trends in Ecology and Evolution 20: 74-80

Crucial gaps in scientific understanding re fisheries:

Larval dispersal to and from MPAs e.g. ‘source’ and ‘sink’ areas?

Movements of juveniles and adults and whether there is a density effect.

Shifts in community structure as we vary the abundance of predation in the system?

Coastal hydrodynamics: water quality, larval dispersal effects?

Management successes and failures

Question 22

Summary

Answer 22

Tropical MPAs provide the strongest examples of increased abundance, size and biomass of site-attached target species (e.g. groupers, snappers) within their boundaries.

Where this increase occurs there is an expectation of spill-over and larval export effects; there is some evidence for the first but the latter remains unquantified and the fishery benefits are variable (e.g. Sumilon and Apo).

There are alternative objectives and approaches to MPA management. MPAs have potential benefits (e.g. nature-based tourism) but there is also a downside (e.g. loss of fishing ground), important in deprived areas, especially in poor countries.

Question 23

WIDER READING establishment of MPA’s alone does not restore coral reed communities.

Answer 23

Cox, C et al, 2017 (Marine Biology Progress Series)

Establishment of marine protected areas alone does not restore coral reef communities in Belize

• Annually surveyed 16 reefs in Belize from 2009 to 2013, 8 MPA’s and 8 unprotected sites.
• Measured the biomass of reef fishes, coral and macroalgal cover, and several biotic and abiotic variables that are known to affect reef inhabitants
• Mean macroalgal cover was above 40% across all sites, and no change in coral cover was observed during the study.
• The results indicate that fisheries restrictions alone do not lead to increases in coral cover even when successful for fishes. Both illegal and legal fishing may be compromising Belize’s MPA network goals.
• Management strategies that are suggested to be required alongside MPA’s are not limited to MPAs for example:
  
  • a recent ban on herbivorous fish harvesting in all national waters in Belize may be necessary to promote parrotfish population recovery independent of MPA’s
    
    • restoring parrotfish populations in locations with high macroalgal cover such as Belize may be not be enough to reverse the shift from coral to macroalgal dominance
  • Strengthening enforcement, limiting poaching within MPA boundaries, and implementing fisheries policies that cross MPA boundaries could promote faster recovery of fish communities.
  • Improving water quality by managing terrestrial runoff and sources of nutrients (particularly sewage treatment) to reduce macroalgae and restoring coral reef communities.

Question 24

WIDER READING: increase fish size, biomass and potential value

Answer 24

Chirico, A, A, D., et al 2017, (PLoS ONE)

‘Community- and government-managed marine protected areas increase fish size, biomass and potential value’

• Compared community-managed MPAs, governmental MPA’s and fished areas on seagrass and coral reef ecosystems using field surveys along the Kenyan coastline.
• MPAs harboured larger sized fish and fish communities with higher biomass and much higher potential monetary value than fished reference areas.
• The study suggests that small and recently established community MPAs s (< 1 km2, <5 years of protection) can increase fish size and total biomass, just like larger government MPAs (> 6 km2; > 20 years of protection).
• In addition, both community and government MPAs benefitted seagrass fish communities in similar ways as coral reef fish.
• The effect of protection of MPA’s was greatest for fish’s monetary value in comparison to density, size and biomass. This is due to the relationship between increasing fish biomass and its monetary value. The effect of time since closure showed a positive relationship with the density of high-value species (primarily rabbitfish).

Question 25

WIDER READING benefots in phillipeano reefs

Answer 25

Eklöf, J.S. et al, 2009 (Marine Ecology Progress Series)

‘Reef-wide beneficial shifts in fish population structure following establishment of marine protected areas in Philippine coral reefs’

• To determine the effect of MPAs on fish density, visual surveys of fish families across 39 pairs of no-take MPAs and fished reefs were taken in the Philippines. Surveys consisted of replicate transects both inside and outside of each MPA.
• Over relatively few years of protection, MPAs in the Philippines were able to promote beneficial shifts in fish population structure throughout entire reef systems rather than simply maintaining stable populations within their borders.
• The benefit to adjacent reefs is important to the success of MPAs in the Philippines because compliance with closures of fishing grounds increases with realized benefits to fishing communities.
• The density of large-bodied fish both within and outside of MPA boundaries increased over the first 5 years of protection. This is critical to food security for sustenance fishermen and the sustainability of fish populations.
• Increases of species targeted by fisherman within the zones were able to offset declines outside the MPAs, making the whole population stable on the reef. The average sizes of these fish on the reef were seen to increase.