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02 October, 2007

Shrimp Sampling 01 - Background, Objectives and Types of Samplings

Shrimp sampling is an activity that is absolutely necessary in an activity on the shrimp farming. As noted in earlier discussion, that one of the characteristics of shrimp farming is 'unvisible object', which means that any behavior, condition and growth of shrimps in ponds can not be observed directly because it was blocked by the waters of the habitat. Based on the characteristics, one of the alternative activities that can be carried out to estimate the profile of shrimp in the pond is through sampling activities.

Shrimp sampling in a simple can be interpreted as activities to take a few sample of shrimp in one population within a specified period of time. Referring to the notion mentioned above, it is suggested should be carried out sampling activities on a regular basis from the fry until big shrimp and time to harvest. The purpose of sampling on shrimp farming in general, among others, to know:
  1. Shrimp condition associated with quality of shrimp. At the time of sampling can be made direct observation of the quality of shrimp into the sample observations. Results from observations of several conditions of shrimp from sampling activities can be used as a reference in decision making in the provision of treatment / treatment related to the technical cultivation. In certain circumstances / special, when the shrimp exposed to severe category of problems with sampling activities can be used as a basis for a decision that led to the harvesting.

  2. Shrimp uniformity level, ie uniformity level of shrimp size and weight in a population at relatively the same age at a specific time period. Level of uniformity of shrimp in a population is relatively good if the size and weight of shrimp is relatively the same (uniform), on the contrary, if in a population of shrimp has a size and weight of shrimp has varied the level of uniformity is relatively poor. Level of uniformity of shrimp in a shrimp farming will be very influential in the preparation of food programs related to the type, size and weight of feed given daily.

  3. Survival Rate (SR), namely the level of life of shrimp in ponds at a specific time period compared with the initial population. The approach used to determine the value of SR is to calculate the average number of shrimp caught in nets particular area multiplied by the plot of a pond compared to the vast area of the used nets.

  4. Average Body Weight (ABW), which is the average weight of shrimp in a shrimp population during a specified period. ABW is obtained by calculating the total weight divided by the number of shrimp from the shrimp caught in nets.

  5. Biomass of shrimps, ie the number of the total weight of a population at a specific time period and is usually expressed in units of weight. Shrimp biomass can be estimated by multiplying the SR with initial population size multiplied by the ABW of shrimp at a given time.

  6. Size of shrimp. Size of shrimp can be interpreted as a measure based on the number of shrimp shrimp contained in 1 kg of shrimp, or can be formulated as: shrimp Size = 1000 gr / ABW (g). For example: ABW of shrimp = 25 gr, then size = 1000/25 = 40.

  7. Pond bottom conditions. In the sampling activities carried out mainly using nets, one aspect that can be observed other than those related to the quality of shrimp pond bottom is the aspect conditions. Agency at the time of the nets used / thrown into a pond will soon be down to the pond bottom so that when withdrawn in addition to shrimp nets will also bring items, including dirt at the bottom waters. The observation that needs to look at is the existence of black mud and dead shrimp under conditions outside the acceptable limit.

  8. The presence and level of predator / competitors populations in the pond. At the time of sampling using nets can predict the type and density of predators / competitors who live side by side with the shrimp within the pond.
As a side note: the item no (2) and no (4) above is still a rough estimate of value however the shrimp aquaculture as an object has a characteristic that can not be regarded as a static object and spread flat on the pond bottom.

Referring to some shrimp sampling purposes mentioned above, we can conclude that the results from sampling activity are expected to serve as the basis of considerations in terms of:
  1. Making technical decisions related to their cultivation in accordance with the conditions / quality of shrimp and the pond bottom conditions at that time.

  2. Estimation / adjustment needs an appropriate level of shrimp feed shrimp needs at that time.
As already mentioned above that the shrimp sampling activities should be conducted regularly from the age of shrimp fry until shrimp adult age and just before harvest. Duration of time between sampling events within a period of shrimp culture in its application in the field can be said to vary depending on the habit, for example, 10 daily, 20 daily or once a month, which primarily is its periodic and regular.

In addition to periodic and regular sampling, under certain conditions can be carried out incidental sampling caused by infected shrimp indicated a problem, so it needs to direct observation of the quality of shrimp in the pond in an attempt to estimate the level of sustainability of one cycle of cultivation in these ponds. Especially for indications of problems characterized by mass mortality of shrimp in the pond bottom, then by performing the sampling nets can be estimated severity of the problem. If the shrimp death had spread in pond bottom can be indicated then that problem is very serious level and decision-making should lead to harvesting. Incidental sampling is also commonly done at the time before normal harvest primarily to provide data / information to prospective buyers about the size and quality of shrimp produced, so it can be an agreement on price / value of sale of shrimp.

Based on the tools used the activities of the shrimp can be divided into two types namely:
  1. Sampling using ancho. The sampling activity is performed using the tool as a means of ancho on shrimp sampling. Sampling using ancho is usually done for the shrimps are still relatively small. Note: Ancho in shrimp farming is a tool used to control the feeding programs, growth and quality of shrimp on a daily / insidental. Ancho usually a square the size of 1 mx 1m with a frame of wood / iron, and its center is associated with nylon gauze.

  2. Sampling using nets. The sampling activity is performed using the tool as a means of nets of shrimp sampling. Sampling using nets are usually done for the shrimps and relatively large size (> 2.5 g) was thus caught in a used mesh. Commonly used nets is 6 meters on diameter, length 3 to 4 meters with mesh sizes vary depending on location and the producer (adjusted mesh size of shrimp is the target sampling). Although the tool used is different but the goals to be achieved almost the same relative that is to know the condition / quality of shrimp and water as described in the above explanation.
In addition to the above two types of sampling are also sampling of fries. The sampling activity is usually done at the time of fry procurement benur at hatchery and at the start of the fry density sampling. The goal of sampling is more directed fries estimate the number / population of fries, as well as the condition / quality will be stocked fry. The sampling activity is done manually counting and careful visual observation, so that at the time of the density can know what level of density (population) and the condition / quality of fries in a pond.

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Related Post :

  1. The Concept of Size and Quality of Shrimp for Price
  2. Shrimp Sampling-04 - Sampling of Jala
  3. Shrimp Sampling 03 - Sampling of Ancho
  4. Shrimp Sampling 02 - Equipments/Tools and Shrimp Sampling Stages

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