LM PRawn model
Introduction
The production of cultivated penaeid prawns in pond culture is an important economic activity in many coastal systems throughout the world. This website is designed for the farmer or for licensing purposes, in order to determine the appropriate density for optimal carrying capacity (the greatest sustainable yield of market-sized animals within a given time period). The intended scope of application is for shrimp farms, with or without application of artificial feed, in coastal and estuarine waters.
Prawn/Shrimp farming and its environment
Shrimp are cultivated in ponds and as rule artificially fed. Water renewal is usually carried out through a system of sluices, and sometimes occurs only a few times over a year.
In some countries, these ponds are used for polyculture. When shellfish are cultivated in this type of Integrated Multi-Trophic Aquaculture (IMTA) system, they are able to use waste matter from the shrimp culture, both from excess feed and from shrimp metabolism. This organic detritus, together with chlorophyll a (Chl a) forms the natural food supply which is filtered and eaten by shellfish such as razor clams. The shellfish reduce eutrophication symptoms in the pond, helping to promote higher dissolved oxygen levels, which in turn reduce shrimp mortality. Additionally they constitute a valuable crop in their own right.
The LMPrawn model allows you to calculate the yield of the farm based on:
food supply;- farm size;
- shrimp density;
- environmental parameters.
MODEL DESCRIPTION
Inputs
There are three types of settings, Environment, Farm Dimensions and Prawn/Shrimp Stock.
Environment - The environmental parameters determine the food supply to the farm. These include the current velocity and the concentration of the various food sources - example values are given in the table. Please change these to the ones that apply to the region of your farm.
Farm Dimensions - The farm dimensions are a critical factor in determining carrying capacity at the farm scale. This model considers a rectangular farm - example values are given in the table. Please change these to the ones that apply to your farm.
Prawn/Shrimp stock - You can define the shrimp stock in the farm. The stock you define is considered to correspond to small animals at the start of cultivation. The LMPrawn model calculates the shrimp densities for the shrimp farm based on your stocking definitions - example values are given in the table. Please change these to the ones that apply to your farm.
Model Run
- The model uses five weight classes for prawns: 2-6g, 6-10g, 10-14g, 14-18g and 18-22g (fresh weight), and will run for a period of several months;
- To run the model, hit the Simulate button;
- With the default settings, the model simulates a cultivation period of six months, and takes about ten seconds to run;
- The model also simulates the concentration of dissolved oxygen. This is combined with chlorophyll for assessment of environmental impact using the ASSETS method.
Outputs
After the model has run, results are produced for:
- Chlorophyll and dissolved oxygen concentration;
- Number of adult (harvestable) shrimp;
- Adult prawn shrimp (or if you are looking only at one individual, the final total fresh weight of the individual);
- Production analysis, including input/output, called the Average Physical Product (APP).
Saving and loading a model
The values you enter as inputs may be saved for future use. After you define the inputs, run the model to see the results. Then write your chosen model name in the Save model box and click the disk icon.
To load a previously saved model, choose it from the Open a model box. Models are saved on your computer (as cookies); this means that if cookies are disabled you will not be able to use this feature, and also that you will not be able to retrieve models saved on another machine.
Run the LM PRAWN model
Polite notice: The LM Prawn Model runs only on Internet Explorer. For IE8 users, please make sure that the "Compatibility View" option is selected in the "Tools" section. We apologise for this inconvenience.
UNIQUE LM PRAWN FEATURES
LM Prawn is available for use as a console version. The console version provides additional outputs which are not included in the web based version.
LM Prawn Drivers
- Allows for modelling of Penaeus vannamei and Penaeus indicus;
- Accounts for different types of shrimp farm layouts and number of ponds;
- Simplified driver data to run LM Prawn model;
- Allows users to input mortality, seed cost, sale price, feed cost, culture periods, etc.
LM Prawn Output & Results
- Growth modelling results for prawn/shrimp;
- Analysis of water quality effects, including dissolved oxygen, particulate organic matter, etc;
- Production analysis including total physical product, cost curves and profit maximising outputs;
- Produces insights for users about prospective and current shrimp farm operations.
Technical Information
The LM Prawn model and some of its applications have been presented to the industry, managers and scientists in Europe, the U.S. and Asia. A paper describing LM Prawn has been published in the journal Aquaculture. This section contains links to presentations.
Terms of Use and Disclaimer
The LMPrawn model uses state-of-the-art equations in order to determine farm-scale carrying capacity. There is currently no cost for usage. However, the authors cannot accept any liability for losses or consequential damages due to its application.
The model uses only unidirectional advective flow. The farm footprint due to organic enrichment of the sediment is not currently simulated.
Contact
For information regarding the LM Prawn model or any other related question, please contact info@longline.co.uk or visit http://www.longline.co.uk