CONSULTANCY AND RESEARCH IN AQUACULTURE AND THE AQUATIC ENVIRONMENT

1. A Company in the NIVA-group CONSULTANCY AND RESEARCH IN AQUACULTURE AND THE AQUATIC ENVIRONMENT Mitigating the environmental impacts of aquaculture

2. Acceptable impact? For impacts to be acceptable, the impact must be reversible or the ecosystem can recover. Impact to sediments, impact of nutrients in water column • AZE – acceptable zones of environmental impact – local to the farm or licensed area • Zoning of aquaculture so that impact is confined to certain zones Permanent impacts must be considered very carefully with a full risk analysis undertaken. Introduction of exotic species, cutting mangroves for ponds, draining wetlands • Precautionary approach

3. Recovery • Little is known about the rates of recovery of aquaculture sites, and most of what is known is from a small number of studies of abandoned sites. • More is known about short term recovery - fallowing • Oxygen dynamics play a major role in site recovery. Without adequate oxygen some of these processes cannot occur. • Many other factors, including physical conditions related to currents and mixing, can affect recovery.

4. Environmental management of aquaculture Mitigating environmental problems requires concerted action of all farms in the water body. There is pressure to reduce environmental impacts of aquaculture due to increased utilisation of aquatic resources, consumers, governments and the international community Improvements in environmental sustainability of marine fish farming have been the made by use of • fallowing, • improved cage design to minimize escapees • reduced usage of antibiotics.

5. Environmental management of aquaculture There is more effective enforcement of regulations throughout the world, although these measures are targeted at the farm level. Regulations appear to be strong in those countries where the growth of aquaculture has been most rapid and producing high-value commodities. In many countries, the industry has taken the lead to respond to the environmental pressures, mostly driven by market forces. • Producer organisations - Codes of Conduct, best practice, etc. • Wallmart – GAA – sustainable sources

6. Mitigation of impact As a general rule, inputs should be minimized or more efficiently used where possible. Mitigation of aquaculture impacts can take a variety of forms. • Improved feed quality • Improved feeding strategy • Fallowing • Distance between farms • Zoning • Extractive species • Integrated aquaculture

7. Fallowing • Fallowing is the removal or cages from an area after production to allow the sediments to recover before starting production again • It has been shown in Norway to reduce outbreaks of disease • It allows sediments to become repopulated. • Recovery rate of sediments is dependent on • Temperature • Oxygen • Currents • Level of impact

8. Improved feed conversion rate Feed is the greatest input to fish farming. If you can reduce feed input you will reduce waste output and environmental impact Automated feeding especially with feedback systems have significantly reduced feed inputs whilst maintaining productivity. In salmon farming feed conversion ratio have been reduced from 1.5 to near 1.1. Such reduction reduceds organic matter and nutrients discharged to the environment. However, other types of aquaculture (sea bream and sea bass in the Mediterranean Sea) have FCRs close to 2:1 and still need to improve their feed conversion ratios.

9. Improved digestibility of feed Dry Feed • Addition of a higher percentage of digestible proteins • Extruded feed vs pelleted feed

10. Improved feeding strategy – quantity of feed • Timing • feeds per day • Quantity per feed • Quantity of feed is affected by • Size of fish • Water temperature • Growth rate

11. Feeding Improved feeding strategy - timing

12. Feeding timing • In the Mediterranean, until we studied feeding behaviour of Mediterranean seabass we did not realise that during winter they preferred to feed at night • Fish feeding is affected by • cloudy days • Lightening • Time of day - early morning, early evening • Birds in area • Predator fish beneath cages • etc,

13. Seabream - Specific growth rate

14. Optimal feeding rates

15. Optimal feed conversion rate

16. Optimal number of pellets per day

17. Feed back systems The Mini-lift up is designed to drift with the prevailing current and to place its self under the feed spillage, which has been a problem with the more static solutions on the market. The grid from drain water can be placed on the side of the cage, where excess feed is lifted up by a collector can be viewed directly.

18. Simple cost effective feed back systems Systems to monitor and prevent over feeding such as feeding trays

19. Distance between farms • Minimum distance between farms or farm areas • Prevent disease transfer between farms • Prevent pollution between farms • Allow unimpacted zone between farms for recolonisation of the sediment • Prevent build up of nutrient levels to dangerous levels

20. Zoning Zoning of aquaculture areas • To choose the best areas suited for aquaculture • Calculate carrying capacity for those zones • Limit production within zone (prevent over production) • Restrict impacts to that zone • Prevent conflict with other users of the coastline

21. Use of extractive species • Mollusc or seaweed systems remove nutrients from the culture environment. • Effective integration of fed and “extractive” aquaculture practices can result in increase of productivity and can mitigate against nutrient build up in the environment. • Mixed culture of fish, molluscs and seaweeds practiced in the coastal bays of China is a good example. • However densely located extractive aquaculture systems can cause negative impacts on the environment, especially on sediments, as a result of faecal and pseudofaecal accumulation (Yellow Sea China).

22. Integrated aquaculture Integrated aquaculture (IA) is a concept which has been developed to maximize water use efficiency by growing a number of species together or aqua/agri culture. Increase productivity of scarce freshwater resources and reduce pressure on natural resources. The three main environments are Irrigated systems, floodplains and inland valley bottoms In integrated systems, aquaculture there is multiple use of the water and can increase water productivity (e.g. rice-fish farming in Asia). However there are problems with the continuous supply of water, the use of agrochemicals

23. Managing the sector at an area level Planning and management • Proper zoning • Environmental impact assessments (EIA) • evaluation of the carrying capacity of the environment Some countries are already applying these tools as requirements for aquaculture licensing This helps to reduce the negative environmental impacts of aquaculture and encourage establishing sites in suitable locations.

24. Factors affecting impact • Analysis of monitoring results from 168 environmental surveys on 80 Salmon farm sites in Norway (APN, 2003) has shown that management practices as well as environmental factors play a strong role on the impact of sediments below the cages. • For salmon production in cold waters, management practices such as years in operation (without fallowing) and feeding strategy were found to have greater influence on impact than environmental factors such as current speed and water depth.

25. Multi-factorial analysis of environmental and management variables on sediment quality • Local carrying capacity • Depth • Currents • Sediment characteristics • Sediment turnover • Management practices: • Feeding regime • Stocking density • Time-scale of inputs

26. Analysis of Management Practices in Norway • Historical: • National environmental quality guidelines for coastal waters (1993) • Standardized monitoring schemes (1997) • National standard for monitoring (2000) • Samples (1996-1998): • 80 fish farms represented • 168 stations in the analysis

27. Close (0 m) Main current Intermediate (50- 100 m) Reference (1000m) Spatial distribution of samples • Close – under cages • 41 samples • Intermediate – 50-100m • 39 samples • Reference – 1000m • 49 samples • Baseline samples • 39 samples

28. Selected Parameters for Analysis • Environmental quality measure (Y-variable) • total organic content (TOC) in sediments • Environmental Variables • particle distribution in the sediments • depth at site • water currents • Management Variables • feed consumption over the last 12 months • number of years site is used in production • abandonment of sites (fallowing)

29. Predicted Sensitivity Environmental Quality Categorization of environmental variables

30. Univariate Results

31. Correlations (Spearman Rank Order Test)

32. Conclusions from this analysis • ~ 25% of the sites were heavily effected by organic enrichment • effects were local - 50 to 100 m from the cages, beyond that there was no evidence for increased organic enrichment • depth and speed of water currents are not sufficient as predictors for organic enrichment if used as single variables • fallowing has a strong influence reducing organic enrichment in the sediments

33. Results from EMMA project Environmental management of aquaculture • should be based on carrying capacity of the lake, river or bay area • Should have strong Government planning based on science • Government should control development and enforcement of regulations • Operator management options should be encouraged through Codes of Conduct, best practice, etc.

34. Government planning options • Zoning of aquaculture areas (max production per zone) • placing cages in areas with higher exchange • forcing integrated aquaculture (fish and mollusc/seaweed) • zoning (fish - mollusc - fish - mollusc etc.) • minimum distance between cages • minimum distances between farms • mariculture parks (controlled development) • controlled fry stocking season/date • Large farms to be forced offshore • Early warning systems for low oxygen/high algae conc/poor water exchange

35. Government management and enforcement of regulations • Regular environmental monitoring of aquaculture zones • Checking licences • removing abandoned structures • removing unlicensed farms

36. based on carrying capacity of the lake, river or bay area • Limit number of licences (number of cages, pens, etc) • limit number of structures per licence • Limit size of licence (50 tonnes, 100 tonnes/crop) • Limit volume of structure (1000 m3) • Limit surface area of utilisation • limit maximum standing stock biomass (50 tonnes per farm) • limit maximum density of stocking (fry per cage) • limit maximum density in cage (15 kg/m3) • Limit food purchase per farm • Limit food delivery per area

37. Other operator management options • Codes of Conduct • Best practice guidelines • limit maximum density in cage (15 kg/m3) • improved feeding strategy (time, frequency, quantity) • harvesting before risk periods • not feeding during risk periods • controlled stocking fry to miss high density during risk periods • moving cages after production to new area to allow fallowing of old area • moving further offshore or area with better water exchange