Since culture experiments often involve more than one species, production by species is reported in this sub-table with one record per species used. Included in this table are the stocking practice, culture period, harvesting practice, mortality during the culture period and the gross yield per production cycle. The fields are described below:
Stocking rate: Refers to the amount of fish at the beginning of the culture period. The choices for the unit are: no./m2; no./m3; no./m3/d; kg/m3. This refers only to the species considered in this record.
Total stocking: Refers to the total initial biomass of the considered species, in kg.
Stocking length: Refers to the modal or typical length of individual fish at the time of stocking, in cm. Type of length measurement is also given (SL, FL, TL or OT).
Stocking weight: Refers to the modal or typical weight of individual fish at the time of stocking, in g live weight.
Stocking age: Refers to the average age of the stocked fish, in days. This is important because of old, stunted fish that might grow very slowly and might start to breed at small sizes.
Method used for estimation: Refers to the method used for growth. Choices include: Ford/Walford plot, von Bertalanffy/Beverton plot, Gulland and Holt plot, non-linear regression, ELEFAN I and other methods.
The von Bertalanffy growth parameters (L¥ , K) are given as the preferred measure for growth in length. These are described in more detail in a separate table (POPGROWTH table, this vol.), which distinguishes between fish grown in ‘captivity’ and in ‘open waters’ (see also Box 16 and Fig. 21).
Culture period: Refers to the duration of production from, e.g., fingerlings to marketable size, in days.
Harvesting practice: Refers to the method used in harvesting the stocked fish. Choices are: batch culture; continuous stocking and harvesting; periodical stocking and harvesting; periodical stocking and continuous harvesting; variable.
Harvesting length: Refers to the modal or typical length of individual fish at harvest, in cm.
Harvesting weight: Refers to the modal or typical weight of individual fish at harvest, in g.
Mature: Indicates how many fish are mature at harvest with the choices: most; some; none.
Mortality (M%): Refers to the losses encountered during the production period, in %, computed as follows:
....1)
where N0 is the number of fish at the beginning, and Nt the number at the end of period t.
Also, the Annual mortality rate (Z) is calculated as follows:
…2)
where M% is as defined, and D t = production period, in days.
The Specific growth rate (in %) is calculated as follows:
Ln (harvesting weight - stocking weight)
· 100/D t.
Gross yield:
Net yield is the Gross yield minus the biomass at stocking.
Extrapolated yield gives the hypothetical gross yield that would have been obtained had conditions remained the same and the production period lasted 365 days.
Comment: A field for miscellaneous remarks not addressed by other fields.
This table currently holds over 550 records. A graph is available which distinguishes the growth patterns of captive fishes from those of fishes in open waters (see Fig. 21).
There is a huge amount of literature dealing with aquaculture. Extracting usable information from this is quite difficult because there is a lack of standardization in the experiments. Note also that most of the references used in this table deal with freshwater fishes.
Clicking on the Biology button in the SPECIES window, the Fish as food button in the following window, the Aquaculture button in the BIOLOGY window and then the Cultured species button in the CULTURE SYSTEM window will bring you to this table. A list of species studied (for polyculture systems) is given and selecting a particular species and clicking on the Production button will give detailed information on yields. The graph in Fig. 20 is accessible from the Graphs Menu under Population Dynamics.
The CULTSYS and CULTSPEC tables were not yet available on the Internet in November 2000.
We thank Barry Costa-Pierce, Mikkel Christensen, Mark Prein and Anne van Dam for providing their data for distribution through FishBase and for their suggestions on how to improve the CULTSYS and CULTSPEC tables. We thank Liza Agustin, former member of the FishBase Team, for her contributions to this table and to a previous version of this chapter, while a member of the FishBase Team.
Roger S.V. Pullin and Christine Casal