Socioeconomic data

Population segments for collection of economic and social data for fisheries

  1. Description of methodologies used to choose the different sources of data.

Collection of the economic variables of the fleet is based on two major data sources:

  1. a) Fishery Information System administered by DoF (fishing activity variables, volume and value of blue diesel consumed per vessel; information on subsidies etc.); and
  2. b) Questionnaires for economic data collection.

The consistency of information coming from questionnaires and administrative sources is assured by cross-checking information from the different data sources.

  1. Description of methodologies used to choose the different types of data collection.

Economic variables will be collected by questionnaires; the type of data collection scheme is probability sample survey by stratified random sampling and in some cases a census survey. For the variables Consumption of fixed capital and Value of physical capital Indirect survey shall be applied.

  1. Description of methodologies used to choose sampling frame and allocation scheme.

Based on the basic data on the population and data on the use of fishing gears retrieved and stored, after data has been validated and verified, a segmentation of the fishing fleet is performed. In some cases fleet segments are clusered for sampling purposes or reporting purposes for confidentiality reasons. As clustering depends entirely on the activity of vessels, in cases where clustering is needed, vessel activity is reviewed on a vessel to vessel case. In cases where a vessel changes its activity from one year to another inconsistently, it is directly reflected in the clustering.

On the basis of determined fleet segments, the procedure for determining sample sizes is carried out.

In order to estimate the sample size for the collection of economic variables, the variability of GT and kW is calculated. Coefficient of GT variation is used as a basis to define the sample size of the total fleet.

The sample is distributed among the relevant strata with the principal objective of minimizing the sampling error to be obtained for the stratification variable. The optimum Neyman allocation, which guarantees a minimum variance for the variable used in the stratification, is used for this purpose.

The sample size for each stratum is adjusted in accordance with several minimum rules: not less than 10% of each stratum, not less than 5 observations per segment with <50 active vessels assuming the response rate of 50%. According to the distribution of the GT few segments need to be sampled on census basis.

  1. Description of methodologies used for estimation procedures

Estimation procedures are performed according to agreed methodologies published on the official DCF web site (

In cases where response rate is inadequate to reach a statistically sound estimation, a simple regression is used to cross-check results or estimate totals. Low response rate is typically a problem of data collection for the small-scale fleet, for which questionnaire return rate is low, data in questionnaires inconsistent, unreliable and sometimes unreadable as in most cases there is no professional accounting. To tackle these issues, considerably more effort is placed into data collection for the fisherman involved in small scale fisheries, including direct contact, reviewing questionnaires, cross checking data to ensure a more complete data sets, higher quality and more reliable results.

The calculation of variables Consumption of fixed capital and Value of physical capital is based on data from questionnaires and financial accounts in accordance with the PIM methodology, proposed in the report of study No FISH/2005/03. The age data is available per each vessel in the Fleet register. The data on the value of physical capital (replacement, insurance and purchase is collected through the questionnaire by DoF). The proposed DCF Excel template for the calculation of the capital costs will be used.

Estimation of direct subsidies: DoF records on direct subsidies are used as well as questionnaires. In cases where enterprises have more than one vessel, the amount of subsidies is allocated to vessels based on GT, as subsidies are collected on an enterprise level. The estimations are cross-checked by allocating the total amount of subsidies paid to respective fleet segments using the share of landings value of the fleet segment. In the end, three sets of estimations are compared to reach a sound conclusion.

Estimation of energy consumption and energy costs: For the estimation of energy consumption and energy cost blue diesel records are used. The register of blue diesel is updated annually on the amount of fuel consumed per vessel. No estimation to determine totals is used, as data is collected on a census basis. In order to estimate energy costs, data is collected both via questionnaires and by using average fuel prices.

Estimation of FTE: The number of hours worked during the year, collected from the enterprises through the economic questionnaire, is divided by national annual full-time working hours (based on the CBS methodology 2084 hours).

  1. Description of methodologies used on data quality

To ensure the quality of data collected accuracy of the data that will be calculated. The data quality evaluation depends on the data collection scheme. In all cases (census and probability sampling) unit response rate (number of enterprises responded/total sample) and item response rate (response rate per each variable) is calculated as follows:

– Response rate (per item j);

N – Total number of vessels in the sample;

n – Number of vessels which provided the data (questionnaire/per each variable).

Coverage rate (number of responses/total population) is calculated in case of probability sampling survey.

It is planned that random samples be used and the sample size adjusted in accordance with the response rate during the implementation.


Population segments for collection of economic and social data for aquaculture

  1. Description of methodologies used to choose the different sources of data

There are two main sources of data –  some variables will be collected from DoF database and subsidies register while some will be taken from questionnaires. For cross-checking, data from the Croatian Financial Agency (FINA) will be used, which is mostly connected with the balance sheet, but only for companies who have to deliver their data due to their size category or net profit.

  1. Description of methodologies used to choose the different types of data collection

Data collection for all techniquest and species groups shall be carried out on the basis of a census, except for Long line-Mussel which shall be sampled on the basis of a Probability Sample Survey.

Data collection will be conducted by phone contact with subjects, introducing them with the data collection, and sending questionnaires together with guidelines by post or email. To ensure data consistency for all segments, together with each variable defined in guidelines it will be given the link to accounting code in balance sheets. The subject will have time two weeks to prepare documentation for data collection and after that a data collector will arrange a visit to farm office or accounting office to check and collect the requested data. For some cases where it is not possible to ensure direct contact, the subjects answer the questionnaires with telephone consultation and send it to DoF by e-mail.

  1. Description of methodologies used to choose sampling frame and allocation scheme

Segmentation will be based on species and technique. Since a large number of enterprises are producing more than one species, additional segmentation is based on the value of production attributed to one species.  Collecting data shall be for all segments by a census, except shellfish farm, where collecting is based on probability sampling.

  1. Description of methodologies used for estimation procedures

One of the main problems is low response and cooperation so estimation needs to be used. Missing variables can be estimated from the FINA database and from Croatian national statistics bureau. Also, additional attention will be made on collecting data, especially on small-scale companies in marine aquaculture, so as in freshwater aquaculture. Since in Croatia there are different levels of enterprises legal registration with different accounting methods, it came clear during data collecting that is necessary to adjust guidelines for each of them. Two different questionnaires with different approach shall be devised. The first one, for small-scale companies, tailored to their business activities and the way of leading accounting records. Other for larger companies where it is easier to respond to inquiries and requests submitted to them.

  1. Description of methodologies used on data quality

Data collection will be performed through questioners created for this purpose. To ensure data consistency for all segments, together with definition of each variable in guidelines, link is made to accounting code in balance sheets. Some of variables also will be collected from the DoF subsidies register, since it is mandatory for all aquaculture producers in Croatia to report the production in volume and value each year at the farm level. Some of the variables will be taken from questionnaires. Some other variables, e.g. subsidies, will be collected through DoF register and questionnaires. For some segments with small-scale companies it will be necessary to put additional effort in future data collection since they have difficulties in recording financial documents.