In the first project phase, we have to coordinate your fish production and the appropriate process technology. The production plan is of vital importance for dimensioning or evaluation of the aquaculture systems. Either give me the production capacity or it will be limited by location factors like need for space (plot of land, existing buildings) and water availability (water intake, sewage discharge, existing aquaculture systems):
Fish production in water-saving RAS is limited by the nitrate content. For intensive production in aerated flow-through systems with water recirculation the pH value also has a decisive influence on the water demand. It is no longer the oxygen or carbon dioxide content but instead ammonia that is decisive:
Surface waters are mostly used for flow-through systems. The rearing conditions can therefore only be controlled to a limited extent, as there is a strong dependence on the receiving waters. Due to the high dilution, the runoff water from flow-through aquaculture is moderately polluted. Only the solids have to be removed mechanically before discharge.
The growth of the fish is determined by the water temperature in the course of the year. Depending on the frequency of stocking, I have to take different growth curves into account.
Recirculating Aquaculture Systems (RAS)
RAS are based on water transport and mechanical, biological, physical and chemical water treatment. By this RAS minimize water demand and realize optimal control of farming conditions. The wastewater from RAS is heavily polluted and must be treated mechanically (sludge, turbidity), biologically (nitrogen, BOD) and chemically (phosphorus) before it is discharged.
RAS are usually designed as indoor systems. Well water is usually used for fish farming in RAS. RAS with denitrification and ozonation require particularly little water:
Conventional RAS design
Parallel connected circular, rectangular or D-End fish tanks are the normal standard for rearing fry and fingerlings in hatcheries and for growout in small-scale and medium-scale RAS. Following figures show medium-scale circular tank RAS suitable for the production of trout, sturgeon, perch-like fish (pikeperch, barramundi, HSB, Nile tilapia, etc.) and carp:
Unique RAS design
For fish farming on a larger scale, I have developed unique RAS designs for growout and broodstock systems in recent years:
Raceway Loops© rex-m
Habitat: Parallel connected Raceway Loops –
Water depth < 2m
Characteristic: Raceway Loop internal recirculation and degassing
Benefits: Subdivision raceways, availability floor space, system security
Species: Trout, charr, sturgeon (caviar), tilapia, HSB, catfish, carp
Circular Tank Twins© rex-m
Habitat: Two large Circular Tanks –
Water depth > 3m
Characteristic: Separate water supply for each individual fish tank
Benefits: Water current, floor space required, investment costs
Species: Trout, coho salmon, tilapia, barramundi, pangasius, carp
The capacity of the fish farm, i.e. productive volume, flow rate and water treatment, is based on the parameters product, stocking material, stocking rate, species-specific indicators (growth, stocking densities, feeding, losses) and water supply. I differentiate the production of eggs (caviar, ovulated caviar), fish seed (fry, fingerlings, on-grown fish) and food fish.
Salmonids, sturgeon, perch-like fish, carp and catfishes are excellently suitable for aquaculture production. Retail price is market-specific and regularly correlates with the degree of domestication, difficulty, automation and processing:
SALMONIDAE – SALMONIDS
Atlantic salmon (Salmo salar, 2015: 2300 kt) dominates aquaculture in cold waters. Smolts are produced in land-based aquaculture systems. On-growing mainly is done in net pens.
Production of rainbow trout (Oncorhynchus mykiss, 2015: 900 kt) and coho salmon (Oncorhynchus kisutch, 2015: 150 kt) is of global interest too. These anadromous fish are euryhalin. Fishing, grading and counting is done by machine. All the year-round hatcheries provide fertilized eggs.
Farming cold-loving charr (Salvelinus spp.) and sensitive whitefish (Coregonus spp.) is more ambitious.
ACIPENSERIDAE – STURGEON
On a global scale Siberian sturgeon (Acipenser baerii, 2016: Caviar 31% / Meat 40%) is the dominant species. Sturgeon are mainly produced in the northern hemisphere.
Russian sturgeon (Acipenser gueldenstaedtii, 2016: Caviar 20%) provides ossetra caviar. Chinese make use of hybrid sturgeon (H. dauricus x A. schrenckii, 2016: Caviar 13%), North America and Italy of white sturgeon (Acipenser transmontanus, 2016: Caviar 12%). Beluga caviar (Huso huso) is the most expensive one. However beluga mature explicitly after. Instead sterlet (Acipenser ruthenus) matures most rapidly.
The hybrids H. dauricus xA. schrenckii and A. baerii x A. schrenckii share 36% of the global meat production, followed by Amur sturgeon (Acipenser schrenckii) with a portion of 10%.
PERCIFORMES – PERCH-LIKE FISH
Among perch-like fish, the biggest order of vertebrates, Tilapia (2015: 5350 kt) is the dominate genus. Following carp (2015: 26050 kt) the mouth breeder is number 2 in aquaculture. The most common is Nile tilapia (Oreochromis niloticus, 2014: 3670 kt).
Farming yellowtail (Seriola spp.), Barramundi (Lates calcarifer, 2015: 100 kt), titled Asian seabass too, groupers (Epinephelus spp., 2015: 50 kt), cobia (Rachycentron canadum, 2015: 50 kt), snappers (Lutjanus spp.) and HSB (Hybrid Striped Bass, 2014: 6 kt) is of global interest.
Asians produce Mandarin fish (Siniperca chuatsi, 2014: 294 kt) and snakeheads (Channa spp.). Gilt-head sea bream (Sparus aurata, 2014: 158 kt), European seabass (Dicentrarchus labrax, 2014: 156 kt) and meagre (Argyrosomus regius, 2014: 12 kt) are the dominant species in Mediterranen mariculture.
Europeans work on the domestication of pikeperch (Sander lucioperca, 2014: 0,89 kt). European perch (Perca fluviatilis) is produced in the Alpine region, yellow perch (Perca flavescens) in the area of the Great Lakes. Australia offers murray cod (Maccullochella peelii), jade perch (Scortum barcoo) and silver perch (Bidyanus bidyanus).
SILURIFORMES – CATFISHES
Shark catfishes (Pangasius spp., 2015: 2000 kt) are number 4 in aquaculture of finfish. Iridescent shark (Pangasianodon hypophthalmus) and basa fish (Pangasius bocourti) are well-known representatives.
African catfish (Clarias gariepinus, 2014: 237 kt) is able to breathe air and to tolerate incredibly high stocking densities and water parameters. American catfish in industrial-scaled aquaculture are channel catfish (Ictalurus punctatus, 2014: 390 kt) and blue catfish (Ictalurus furcatus).
Wels catfish (Silurus glanis) is farmed rearly by a couple of experts yet. The biodiversity of Amazonia proffers fantastic candidates. So family Surubi with its representative Pintado (Pseudoplatystoma corruscans), regional named Moleque, Bagre rayado or Pintadillo, rates as exquisite gourmet fish.