Categories Fish farming

aquaculture makes use of local photosynthetic production (extensive) or fish fed external food supply (intensive).

extensive aquaculture

aqua-boy, norwegian live fish carrier used serve marine harvest fish farms on west coast of scotland

growth limited available food, commonly zooplankton feeding on pelagic algae or benthic animals, such crustaceans , mollusks. tilapia filter feed directly on phytoplankton, makes higher production possible. photosynthetic production can increased fertilizing pond water artificial fertilizer mixtures, such potash, phosphorus, nitrogen, , microelements.

another issue risk of algal blooms. when temperatures, nutrient supply, , available sunlight optimal algal growth, algae multiply @ exponential rate, exhausting nutrients , causing subsequent die-off in fish. decaying algal biomass depletes oxygen in pond water because blocks out sun , pollutes organic , inorganic solutes (such ammonium ions), can (and do) lead massive loss of fish.

an alternate option use wetland system, such of veta la palma in spain.

to tap available food sources in pond, aquaculturist chooses fish species occupy different places in pond ecosystem, e.g., filter algae feeder such tilapia, benthic feeder such carp or [catfish, , zooplankton feeder (various carps) or submerged weeds feeder such grass carp.

despite these limitations, significant fish farming industries use these methods. in czech republic, thousands of natural , semi-natural ponds harvested each year trout , carp. large ponds around trebon built around 1650 still in use.

intensive aquaculture

in these kinds of systems fish production per unit of surface can increased @ will, long sufficient oxygen, fresh water , food provided. because of requirement of sufficient fresh water, massive water purification system must integrated in fish farm. 1 way achieve combine hydroponic horticulture , water treatment, see below. exception rule cages placed in river or sea, supplements fish crop sufficient oxygenated water. environmentalists object practice.

expressing eggs female rainbow trout

the cost of inputs per unit of fish weight higher in extensive farming, because of high cost of fish feed. must contain higher level of protein (up 60%) cattle feed , balanced amino acid composition, well. these higher protein-level requirements consequence of higher feed efficiency of aquatic animals (higher feed conversion ratio [fcr], is, kg of feed per kg of animal produced). fish such salmon have fcr around 1.1 kg of feed per kg of salmon whereas chickens in 2.5 kg of feed per kg of chicken range. fish not use energy keep warm, eliminating carbohydrates , fats in diet, required provide energy. may offset, though, lower land costs , higher production can obtained due high level of input control.

aeration of water essential, fish need sufficient oxygen level growth. achieved bubbling, cascade flow, or aqueous oxygen. clarias spp. can breathe atmospheric air , can tolerate higher levels of pollutants trout or salmon, makes aeration , water purification less necessary , makes clarias species suited intensive fish production. in clarias farms, 10% of water volume can consist of fish biomass.

the risk of infections parasites such fish lice, fungi (saprolegnia spp.), intestinal worms (such nematodes or trematodes), bacteria (e.g., yersinia spp., pseudomonas spp.), , protozoa (such dinoflagellates) similar in animal husbandry, @ high population densities. however, animal husbandry larger , more technologically mature area of human agriculture , has developed better solutions pathogen problems. intensive aquaculture has provide adequate water quality (oxygen, ammonia, nitrite, etc.) levels minimize stress on fish. requirement makes control of pathogen problem more difficult. intensive aquaculture requires tight monitoring , high level of expertise of fish farmer.

controlling roes manually

very-high-intensity recycle aquaculture systems (ras), production parameters controlled, being used high-value species. recycling water, little used per unit of production. however, process has high capital , operating costs. higher cost structures mean ras economical high-value products, such broodstock egg production, fingerlings net pen aquaculture operations, sturgeon production, research animals, , special niche markets such live fish.

raising ornamental coldwater fish (goldfish or koi), although theoretically more profitable due higher income per weight of fish produced, has been carried out in 21st century. increased incidences of dangerous viral diseases of koi carp, high value of fish, has led initiatives in closed-system koi breeding , growing in number of countries. today, few commercially successful intensive koi-growing facilities operating in uk, germany, , israel.

some producers have adapted intensive systems in effort provide consumers fish not carry dormant forms of viruses , diseases.

in 2016, juvenile nile tilapia given food containing dried schizochytrium in place of fish oil. when compared control group raised on regular food, exhibited higher weight gain , better food-to-growth conversion, plus flesh higher in healthy omega-3 fatty acids.