Health Issues Related to Aquaculture

Nutrition:

-Farmed fish have less diet variation
-Higher fat content
-Fat concentrates PCBs and heavy metals
-Salmon fed dye to give them a red hue (but the dye is supposedly healthy for humans)
-Catching small fish to feed farmed predatory fish is depleting South American fisheries

Disease:

-High density leads to disease
-Farmed fish are kept on antibiotics, which lead to resistant strains and allows them to pass disease to wild fish
-the antibiotics can be misused
-excessive amounts result in potential toxicity
-often times fish get bacterial infections because their immune systems have been weekened by another stress(drastic changes in water temp, frequent transport, etc)
-farm-raised shellfish are particularly susceptible to bio-accumulation of "environmental residue"

why is disease transfer more apparent in fish farms?
-the density of the fish allows disease to spread faster
-in the wild diseased fish are rarely noticed as they are often just eaten by predators before they can spread disease

different aquaculture systems harbor the spread of disease more than others
-recirculating systems spread the fewest disease; water can be treated before it is released into the wild
-caged systems have the most disease because there is an immediate transfer of water into the wild

examples of problems
-salmon farms in particular have a lot of sea lice, a parasite
-abalone transferred to california for farming purposes gave rise to a parasitic worm affecting populations of this mollusk
-oyster farms usually raise different species together which has harbored the spread of disease around the world

sources
dave
http://www.seaweb.org/resources/aquaculturecenter/documents/Aquaculture.Diseases.pdf
http://www.biology.duke.edu/bio217/2005/ncm3/risks.htm

Fish Farm Construction

By far, the most common type of fish farm is pond-based farming. These fairly simple to build, and can thus be integrated into unused land for fishing, recreation or small fish harvests. The steps to build a pond are:

  1. Choose a fairly level site with a high water table
  2. Excavate land to desired level, building excavated dirt into a berm around pond
  3. Create a slight gradient from the inlet to the outlet (This is one of the most difficult parts to get right, and varies from pond to pond)
  4. The pond's depth should be between 3 and 6 feet
  5. Place netting over the inlet and outlet to prevent stock escape
  6. Put some sort of flow control system near the outlet (gate, steppes, ect)
  7. Stock your pond with fish and plants (this is location dependent)

I have not yet found much information regarding larger commercial farm construction.

Energy and Climate Issues, Competition with Traditional Fishing and Reasons other than Monetary Gain

First I just want to remind everyone about the website www.blackwell-synergy.com.  It's got a lot of scientific journals and stuff that might help us out. 

Next, I'm looking into competition between traditional fishing and aquaculture, and according to one article, aquaculture is actually hindering other fishing.  It says that when companies who plan on starting fish farms come, they get the rights to coastal wetlands that the local fishermen did not own, so the local fishermen are put out of their jobs, and it can really hurt the community.  Also, some of the pollution from the fish farms affects the coast, which hinders any business that depends on the water.  It compares it to traditional farming, where the small farms lose out to the big corporate farms.

Also, the article states that aquaculture is shifting from a means of financial gain, but more to a way to feed the growing populations of most countries.
I'm still searching for any climate and energy issues, but I should be able to find more information now that we know how to use the library.
Habitat Destruction

Most of the energy issues appear to tie in the food web and habitat destruction, so I thought I'd look into that a little bit.

According to one of  my sources, fish farming is wasteful because it takes about 5 pounds of wild fish to feed 1 pound of farmed fish, so this affects the wild population, usually ones that are already dwindling in numbers.  Also, runoff from the farms pollutes the surrounding waters, so wild populations of fish and other marine animals are affected even more. 

In addition to this, the farms bring non-native organisms to new ecosystems, which can be very detrimental.  This hurts the entire system, as food sources decrease and predation of other fish species increases.  But this also has some positive aspects, because some of the escapes fish can serve as new food sources in some habitats that are at risk.

(from fishinghurts.com) 

Effects on Ecosystems and Multitrophic Aquaculture

Here's that article on sponges I was going on about, just in case anybody wants to see it: 

http://proquest.umi.com/pqdweb?did=1296800901&sid=2&Fmt=2&clientId=5482&RQT=309&VName=PQD

This one's a study on tilapia grown with and without prawn. They tended have better survival rates in the polyculture system (with prawn). Hope this makes sense. Just one bit of supporting evidence for multitrophic auqaculture (I'm really a broken record about this)

http://proquest.umi.com/pqdweb?did=1307668871&sid=3&Fmt=2&clientId=5482&RQT=309&VName=PQD

This is a pretty in dept article on what the farmed fish industry should do and where it should go. It touches on a lot of very relevant aspects.

http://proquest.umi.com/pqdweb?did=1256969451&sid=5&Fmt=3&clientId=5482&RQT=309&VName=PQD\\

Aquaculture Proposal: Intensive- Pond and Lake

-         Definition of Intensive (Pond and Lake) Aquaculture

-       Intensive Aquaculture is a form of aquaculture wherein the fish are raised in a hatchery from birth until they are harvested and sold

-       This particular form involves cultivating the fish in either a lake or pond or river setting -         Mechanics of Aquaculture

-       Fish are raised in a man made pond that is preferably in a wetland environment, or possibly near a source of free flowing water (i.e. a river)

-       One recommended method is to build integrated ponds into wetland areas, so that water may flow through the pond, but fish are still contained

-       At times, they need backup generators for emergency aeration -         Operation Regulations

-       Fish must be raised in a healthy environment to ensure that they will be able to be sold

-       Operation of the fish farm must not affect surroundings

-       Also, it is preferred that food source for fish is not another form of fish

-       Water must be tested multiple times a day to prevent disease -         Versatility of Methods for countries and species of fish

-       Most fish can be bred in aquaculture

-       Some farms can hold multiple species of fish

-       As long as fish have fast growth rate, understandable and controllable life cycles, tolerance to many economic conditions, good immune systems, and it helps if they are herbivores or omnivores

-       Tilapia is one type of fish that meets most of the criteria

-       Settings can very from country to country, but as long as the general environmental criteria is met -         Funding

-       Tend to have a high start up cost, yet when farm is successful, it is bound to be a worthy investment -         Economic Impact

-       Aquaculture industry can bring more jobs to a country, thus improve the country's economy and raise the standard of living

-       Gives the country a new possible export -         Cheapest Method versus Most Effective Method

-       In the beginning, this is not a cheap, but with its great production, it is a worthy investment -         Consequences of Immediate Action versus Consequences of Procrastination

-       Due to high increase in population, the use of aquaculture will help meet needs of food
-         Projected Outcomes

-       The use of intensive aquaculture can solve the future problems that stem from (very) possible collapse of fisheries and also can help with the need for food that will come with the population growth

-       Also, aquaculture greatly exceeds production of regular agriculture due to difference in habitat -         Sources

-  http://www.tracc.org.my/Borneocoast/aquaculture/AQUACULTURE.htm

-  Aquaculture by Mike Rice P1415 (Journal)

-  http://vasatwiki.icrisat.org/index.php/Intensive_(closed-circulation)_aquaculture

-  http://northernaquafarms.blogspot.com/search/label/intensive%20aquaculture Possible Solutions

Okay, so based on the goals that were established last Monday, here's some possible solutions that we could look into:

Population Size

1) If fishing in a certain area is halted for a period of time, the fish that are usually fished from that area can be farmed and distributed to the consumers.

2) Farmed fish can be added to the wild population to increase their numbers.

              - Problem- issues with putting genetically modified fish in the ecosystem
 

Predator-Prey Ratio

1) Prey fish can be farmed and put into the wild population to guarantee that predators still have food to survive.

 Recovery of Crashed Populations

1) Use fish farms to feed humans and also breed fish to help regenerate the population.

2) Floating cages to protect eggs from predators (inverse cage):  very little impact on genetics/environment, lots of fingerlings 

Intensive (closed-circulation) aquaculture; ( Points of Discussion )

Technique Involves;

  • cultivate fish in closed areas as long as sufficient oxygen, fresh water and food are provided.
  • Imperative to have sufficient fresh water with a a massivewater purification system
  • aerationof the water necessary for growth but achieved by bubbling, cascade flow or liquid oxygen.
  • Variety of fish species can be grown

Pros and cons

  • Ability to control fish production per unit of surface at your will- increase or decrease based on demand
  • massive water treatment plant is required but no necessary since you can use technique of hydroponic horticulture ( use mineral nutrient solution instead of soil) and water treatment.
  • The cost of inputs per unit of fish weight is higher than in extensive farming, especially because of the high cost of fish food, which must contain a much higher level ofprotein(up to 60%) . This frequently is offset by the lower land costs and the higher productions which can be obtained due to the high level of input control.
  • Risks of infections due to high density, pollutants
  • needs tight monitoring and expertise
  • can compensate for overfishing practices
  • ensures maturity of juvenile fish species. Thus, sustainability of ecological systems. However, fish vulnerable to predators when introduced in the wild
  • cost of maintenance high but can be solved through forming cooperative unions,partnerships between foreign investors, selling of shares or using area as a tourist location.
  • Development in technology and research can reduce long term marginal production costs

Current Statistics shows long term gain with this scheme. For example;

-In 2003, the total world production of fisheries product was 132.2 million tonnes of which aquaculture contributed 41.9 million tonnes or about 31% of the total world production.

-The growth rate of worldwide aquaculture is very rapid (> 10% per year for most species). Example, salmon aquaculture has become a major export in southern Chile,- trickle down effects on city's social and economic development

- Today there are a few commercially successful intensive koi growing facilities in the UK, Germany and Israel.

Overall Solutions

In the solutions task force on Wednesday, they mentioned how aquaculture needs to be a main part of the solution, whether its used before or after the fisheries collapse.  The main thing they wanted to know is "Given that aquaculture will be necessary, what methods/places are best economically?"  In English, that means where is it most productive without having negative effects?  I think with the information we have, we can answer that,  but we still need numbers.  I don't think any of the groups have given us ballpark numbers on how much fish (in weight) will not be able to be taken from the ocean once they implement their ideas.  Once we get those, then we can give an initial possible solutions.

And here are two sites that I just found with some good information:

http://www.northernaquafarms.com/aquaculture/page2.html

and

http://www.fao.org/docrep/005/y7300e/y7300e04.htm

Each gives a few numbers that could help us out.

Now that the solutions meeting has occurred, it seems that the group as a whole is looking for guidelines for implementing aquaculture.  I found the following at http://www.paffa.state.pa.us/paffa2/files/approvedpractices/aquaintens.pdf.  It's like a mini how to guide to create intensive aquaculture facilities.  We could base the national guidelines off this by tailoring it to fit a larger scale.

APPROVED PRACTICES FOR
INTENSIVE AQUACULTURE PRODUCTION

1. Select species appropriate for local conditions
2. Select animals which are healthy
3. Prepare an aquarium for holding, breeding or raising fish
4. Select appropriate physical and chemical filter systems
5. Provide for proper aeration in the aquarium
6. Select appropriate feeds
7. Construct a tank facility
8. Construct a mechanism for solid waste removal
9. Construct a mechanism for ammonia removal
10. Provide for manual or automatic feeding
11. Use water test kits to conduct periodic water tests in tank including dissolved oxygen,
ammonia, nitrite and pH
12. Monitor water temperature
13. Properly sample and weigh fish
14. Calculate daily feed ration
15. Calculate fish growth
16. Properly tag fish to monitor individual growth
17. Properly treat water for salinity, disease or plant control
18. Check system for leaks, algae growth, etc.
19. Perform daily and weekly cleaning of the system
20. Perform necropsy on mortalities
21. Diagnose fish diseases and ailments
22. Provide breeding areas for brood fish
23. Control fish diseases and parasites
24. Care for fry and fingerlings
25. Properly kill and harvest fish
26. Properly prepare fish for retail and/or consumption
27. Complete a PA Fish Commission "Artificial Propagation Permit"
28. Market fish through local outlets
29. Keep accurate enterprise records
30. Summarize and analyze records

 
This raises many good points that I think we could look into.

Useful Sources

In case we need to look into anything else, here are some websites that will help out a lot, with finding information.

  • An Aquaculture Blog: 

All of these provide lots of useful information for our group and people outside of our group to gain more information and understanding of aquaculture.

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