INLAND FISHERIES

Table 2 Population, economic contribution of inland captures fisheries and habitats important for inland capture fisheries production

Table 3 The major systems of inland fisheries habitats in Thailand included in the analysis

Figure 1 Map of 25 major river basins in Thailand

NATIONAL FISHERIES STATISTICS

There are two major categories of inland fisheries statistics: capture fisheries statistics and aquaculture production statistics. For each of these categories, yield and value are collected on a yearly basis and are used to indicate the status and trend in the fisheries sector at the national level.

Figure 4 Composition of inland capture fisheries by species 2004

REVIEWED GROSS PROVINCIAL PRODUCT (GPP) SURVEY IN THE FISHERIES SECTOR

FRAMEWORK FOR PREPARATION OF A NATIONAL SYNTHESIS ON INLAND CAPTURE FISHING IN THAILAND

The overall framework used for the estimation of inland capture fisheries production considered the production yield of fishing households rather than the production of professional fishers (Box 1). Fishing household could be commercial-scale, large-scale or medium-scale fishing households as well as a vast number of small-scale fishing households. The large and medium-scale fishing households are a group that uses large gear and conducts fishing to extract the resources for trade whereas the small-scale fishing households utilize the inland fisheries resources mainly for their own consumption.

Box 1 The overall framework for estimating inland capture fisheries production

In order to get detailed data on fishing households and participation in fisheries for the assessment of production, agricultural census data that provided information on fishing households at the village level were linked with the household production data from the GPP survey. Then the data from the different sources were combined and analyzed to quantify the total freshwater production yield of the fishing households.

A database was developed which effectively merged the data sets required for assessing inland capture fisheries. The data sets included in the database are: the agricultural census, the sample of fishing households under the GPP survey, census and GIS data on water bodies. These data sets were stored together and shared the same spatial references and were further linked to provincial political boundaries. In addition, data on household production and the household participation in the fisheries sector were matched with the GIS database for further spatial analysis. Using GIS gives considerable power in analyzing large data sets and the database also enabled overlay and mapping analysis. Hence, detailed information on production status and trends of inland capture fisheries in Thailand could be more accurately presented and estimated and should therefore be more useful for fisheries resources management and policy.

DATA SETS USED IN THE ESTIMATION

In order to estimate the inland fisheries production, two major parts of official statistics and data sets were used to extrapolate inland capture fisheries production.

INLAND CAPTURE FISHERIES PRODUCTION ESTIMATION

Before carrying out the "trial" estimate of inland capture fisheries production two main aspects were considered. First, data and information should be routinely collected to determine the status and trend of the fisheries sector. Second, the data should cover small-scale fishing households, which are always overlooked. Small-scale fishing households represent a large group of people in the rural area that utilize fisheries production for their own consumption and there is no useful statistical report of production from this sector. Therefore, the study aimed to cover all major groups of people who participate in the fisheries sector and to present more reliable information on inland fisheries production.

Besides strengthening inland capture fisheries information, the study also aimed to provide comments that could help to improve the process of fisheries data collection In addition, the information obtained can help clarify the status and trend in the inland capture fisheries sector and ultimately help to determine two main indicators, namely, a) the participation in the fisheries sector (number of people); and b) the socio-economic value of this sector.

PARTICIPATION IN INLAND FISHERIES SECTOR

Data derived from the agricultural census in 2003 showed that about 13.9 percent of the total households, or 2.5 million households throughout Thailand, conducted fishing activities in various inland fisheries habitats (Figure 5). The highest participation in inland fishing activities is in the North and Northeast regions where people depend more on freshwater fisheries resources to meet their dietary needs. Figure 6 presents the number of fishing households at district level in Thailand.

Figure 5 Total households and fishing households in Thailand and by region

SAMPLING OF FISHING HOUSEHOLDS

The trial study sampled fishing households that had been interviewed under the GPP survey of the inland capture fisheries sector. The sampled households had been asked to report the amount of household production, expenditure and income from fishing activities by habitat type. This survey was carried out throughout the country to estimate inland fisheries production and the value of this sector. Data from the GPP household survey of 2005 was used. After being checked, cleaned and stored in the database, a total of 2 215 households were available for analysis and used for production estimation and mapping.

DISTRIBUTION OF HOUSEHOLD PRODUCTION

The distribution of household production is shown in Figures 6 and 7. Household production by region varied widely among the small-scale and middle-scale to commercial-scale fishing households. Of the total 2 215 households, 77.1 percent reported production less than 300 kilograms (Figure 7). It could be assumed that one-third of the sampled fishing households' production is less than 25 kg/month.

Inland capture fisheries are very important to the livelihoods of the Thai people. Most of the households in the low-production group utilized their production mainly for household consumption, whereas the production from middle-scale to commercial-scale fishing was mainly for sale (Figure 8).

As in other studies/surveys in the fisheries sector, household production distribution from the GPP survey is skewed to the right. Mean production of the total 2 215 households is 401.6 ± 1 090.5 kg/year where half of the total sampled households (median of production distribution) reported their production less than 120 kg/year and 75 percent of the total sampled households reported their production less than 281 kg/year (Figure 9).

Figure 6 Distribution of fishing household in Thailand

Figure 7 Distribution of household production of total 2 215 sample fishing households

Figure 8 Distribution of production of sampled households

Figure 9 Distribution of household production by region

Figure 10 Distribution of production of sampled households divided into four regions

The average household production is different in the four regions (Figure 10). Interestingly, the mean production is highest in the central and southern regions where there were a smaller number of sampled households.

A comparison of the small-scale fishing households and the group of fishing households using larger gear or conducting fishing activities for commercial purpose reveals that the total production of the small-scale fishing households is lower (Figure 11).

Figure 11 Distribution of production of sampled households based on the utilization of production

Figure 12 Distribution of production of sampled households divided into two groups based on amount of fish caught

Following the distribution analysis on household production, 75 percent of the sampled households' production was less than 281 kg/year. Therefore, the fishing households are separated into two groups based on production reported, i.e. households reporting a production over 281 kg/year (large catch households (LCH)) and households reporting a production less than 281 kg/year (small catch households (SCH)). All production amounts from each sampled household are summed even if they came from different fishing habitats. The mean production of the SCH is 101.6 kg/year and for the LCH the mean production is 1 305.6 kg/year (Figure 12). These mean productions are then used to calculate the total production by multiplying with the total number of households in small-scale fishing households (SSFHH) and medium-scale to commercial-scale fishing households (M/CSFHH) (Table 5).

Table 5 Average, median household production of all sampled households and average household production of small-scale and middle-scale to large-scale fishing households and inland fisheries production estimation (tonnes)

AN ESTIMATION OF INLAND CAPTURE FISHERIES PRODUCTION

As stated, the estimation of the total production yield for Thailand is based on two data sets from two different surveys: the agricultural census and the GPP survey of inland capture fisheries. Table 5 summarizes the number of fishing households from the agricultural census and the results of the descriptive analysis of production of 2 215 sampled fishing households including the trial analysis of production. Two methods are used to estimate the total production: (1) estimation of production yield based on all sampled fishing households; and (2) estimation of production yield by separating fishing households into two groups of small-scale (SSFHHs) and medium-scale to commercial-scale fishing household (M/CSFHH).

Mean production derived from a descriptive analysis of the two methods is then multiplied by the number of fishing households from the agricultural census. Results from the two methods are summarized below.

Estimated production based on all sampled fishing households:

• The total number of fishing households in Thailand engaged in fishing in all type of habitat is estimated to be 2 639 582 households.
• The sampled fishing households surveyed under the GPP Survey and included in the trial analysis included a total of 2 215 fishing households and their production came from five major habitats of natural swamp and ponds, river and stream, reservoir, irrigation canal and pond trap accounting for 53, 29, 17, 1 and 0.004 percent of total production, respectively.
• The arithmetic mean of the annual production per household is 401.6 kg, with a 95 percent confidence interval of 385.0 to 418.4 kg.
• The total number of fishing households derived from the agricultural census in 2005 is 2 639 582 households.
• The total production from the GPP survey conducted in 2005 in four regions (which included all provinces) is estimated to be 2 639 582 *401.6 = 1 060 056 tonnes/year.
• Estimated inland fisheries production yield from various habitat types is approximately 1 060 056 tonnes/year, with a 95 percent confidence interval of 1 016 239 to 1 104 401 tonnes/year.

Estimated production based on two separate groups of small-scale and medium-scale to commercial-scale sampling fishing households:

• The total number of households in the two groups ofSSFHHs and M/CSFHHs provided the arithmetic mean of annual production per households of 101.6 and 1 305.6 kg with a 95 percent confidence interval of 96.9 to106.7 kg and 1 202.5 to1 420.9 kg.
• Assuming 75 percent of total fishing households from agricultural census, this gives 1 979 687 households engaged in small-scale fishing and the remaining 659 896 or 25 percent of households conducted fishing for sale or falling into the M/CSFHHs group.
• The total production of SSFHHs or low-fish production group from the GPP survey is estimated to be 1 979 686 * 101.6 = 201 136 tonnes/year whereas the total production from the M/CSFHHs or high-fish production group is estimated to be 659 896 *1 305.6 = 861.560 tonnes/year.
• Estimated inland fisheries production yield from two groups of SSFHHs and M/CSFHHs is approximately 1 062 696 tonnes/year, with a 95 percent confidence interval of 939 828 to 1 140 878 tonnes/year.

The use of production data estimated from fishing households multiplied by the total number of fishing households could be a proper approach for estimating capture fisheries production. Range of fisheries production yield from various habitats including river and stream, reservoir, canal, natural swamp and man-made fish pond, etc. could be estimated to produce about 901 974 to 1 158 592 tonnes per year. This is a little higher than the production estimated in the previous study by Coates (2002) which was from five major habitats types and stated to be 472 314 to 1 118 909 tonnes per year and other estimates (Table 6).

Table 6 Reported and estimated production from inland capture fisheries

POTENTIAL SOURCES OF ERROR IN THE GPP PROCESS

In the GPP survey, information on household production, expenditures and income earned from capture fisheries is collected by means of interviewing a sample of households selected using a statistical sampling technique. The whole process of sampling fishing households and conducting the survey is carried out by the Provincial Fisheries Office. Since some of the provincial fisheries officers do not have basic knowledge of statistical processes, this might cause sampling errors. Preferably, random samples of households should be selected throughout the country by FITC and thereafter the provincial offices should conduct the field surveys.

Besides sampling errors, the ability of households to recall the actual production figure could be another possible source of error. The usual method of collecting fishing statistics is to conduct an interview with the household head and to ask him/her to recall monthly production and the fishing effort spent. It has been demonstrated in scientific surveys that the ability to accurately recall information decays within 48 hours (Coates, 2002). This problem is more prominent in the small-scale production fishing households since the respondents probably get only a small production per day and do not conduct fishing activities throughout the year.