Evaluating Household's Willingness to Pay for Catfish Species Conservation in Lake Hawassa, Sidama National Region State, Ethiopia

Description of the Study Area

The study was carried out in Lake Hawassa, Sidama National Regional State, Ethiopia. It is 275 km from the capital city of Ethiopia, Addis Ababa. The Lake lies in between 60 56’ to 70 0’ N and 380 24’ to 380 28’ E E. Hawassa city characterized by medium rainfall with a mean annual rainfall of 1000 mm. The annual temperature ranges from 140C to 28 0C with a mean 210C [10]. The Lake is surrounded by four districts such as Addis Ketema, Hayk Dar, Tabor, and Tula [11]. The Lake stretches 16km from the Northeast to Southwest direction and extends 8km from northwest to southeast direction having an approximate water volume of 1.3 billion meter cube (45.9 billion feet3). The maximum depth of the Lake is 21.6m (70.9 feet) with a mean depth of 11m [12]. The catchment has a total area of 1455 km2 of which 93.6 km2 is the surface area of the Lake that may increase up to 99.3 Km2 in the rainy season. The annual net groundwater outflow from Lake Hawassa to adjacent basins is estimated at 58 ×106 m3 [13, 14] (Figure 1).

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Sampling Techniques and Sample Size Determination

Three-stage sampling techniques were applied to select sampled respondents. In the first stage, 2 districts were selected randomly from 4 surrounder districts to the Lake. In the second stage, 2 kebeles that are potential in fish production were purposively selected from selected 2 districts. In the third stage, 200 sample respondents were selected using a simple random sampling technique based on probability proportional to the size of the population in the 2 selected kebeles. The sample size of the research was determined based on the Kothari formula for determining the sample size of respondents as follows:

2 $$ n = \frac {z ^ {2} \times p \times q \times N}{e ^ {2} (N - 1) + z ^ {2} \times p \times q} - 1 $$ ( ) Where N is the total size of respondents population, n is the sample size, Z is Z value which is 1.96 as per the table of the area under the normal curve for the given confidence level of 95%, e=margin of error is the plus or minus figure usually, expressed as a decimal (0.05); the estimate should be within 5% of true value. The researchers desire to be used 95% confident that the percentage has been estimated. p=sample proportion, success for each respondent to be included in the sample which is p=0.7, q=1–p, failure for each household to be included in the sample (1- P =0.3).

Types, Sources, and Data Collection Methods

Both primary and secondary sources of data were used in this study. Primary data collected from the surrounding respondents through a structured questionnaire to know their willingness to pay for the conservation of the catfish species and secondary data which was collected from the Lake Hawassa Fishery Association and Hawassa City Agricultural office were used. A Direct (face-to-face) interview method of data collection was used to conduct the survey.

**Descriptive Results**

The socio-economic and demographic characteristics of respondents were computed using minimum, maximum, mean, standard deviation, percentages, frequency distributions, and inferential statistical test. Therefore, a total of 200 respondents from the Addis Ketema and Tabor districts were surveyed and had a complete response. The mean age of respondents is 29 years with a minimum of 15 and a maximum of 65 years. The minimum, maximum and mean distance of Lake from the home of respondents is 1, 180, and 42 minutes respectively which is statistically significant at $t$-value of 2.61. The mean fishing experience of respondents is 9.3 years with a minimum of 0 and a maximum of 50 year/s and also statistically significant at $t$-value of 3.617. The mean landholding size of respondents is 0.23 hectares with a minimum of 0 hectare and a maximum of 2 hectares which is statistically significant at $t$-value of 1.97. The average income of each respondent per year is 85.8 US$ with a minimum of 7.9 US$ and a maximum of 526.3 US$ and also it is statistically significant at $t$-value of 4.92 (Table 1).

From a total of 200 respondents, 165 (82.5%) of them showed interest to contribute money for catfish species conservation since the catfish species population and quality of the Lake Hawassa were decreased from year to year and 35(17.5%) respondents had not been interested. The main reasons of the 35 respondents who had not been interested in contributing money for catfish species conservation were: Proper management of the catfish species conservation is the responsibility of the government (27,77%), I am poor (I cannot pay)(7,20%) and I am satisfied with the current situation (it does not need improvement) (1, 3%) respectively. From the165 respondents who showed interest to contribute money for catfish species conservation, (95,58%) respondents preferred money to be collected through association payment, (45,27%) of them wanted direct payment, and the remaining (25,15%) preferred via the chairman of the kebeles.

Out of the total surveyed respondents, 75% of respondents were found to be males, while the rest 25% were females. From total respondents 14.5%, 5%,16%, 24% and 40.5% had 1,2,3,4 and more than 4 family members respectively. Out of the total respondents 3.5%, 10.5%, 58.5% , 18.5% , 2% and 7% were illiterate, have none formal schooling, elementary, high school, vocational and college/ university respectively. As the surveyed study showed, 21.5% of respondents didn’t take training and 78.5% of respondents took training, and also 28% of respondents weren’t a member of an organization working on an environmental project, and 72% of respondents participated in the environmental project (Table 2).

Probit Model Results

It was applied to estimate coefficients of independent variables for a single bounded dichotomous choice. Before estimating the effect of explanatory variables on respondent’s willingness to pay an assumption test was made for the prevalence of multicollinearity and heteroscedasticity problems. Therefore, from the correlation matrix generated, it was observed that there is no multicollinearity problem. Variance inflation factor (VIF) was 1.32, which is less than ten (10) and implies again there is no series multicollinearity problem. The model passed the assumption test of the overall significance of explanatory variables by using the Wald test. The Wald test takes a chi-squared (χ2) distribution with 10 degrees of freedom was about 72.16 with a p-value (prob> chi2) 0.0000 tell us the probit model as a whole is statistically significant. The likelihood ratio test of overall significance also approves a similar result that the null hypothesis of zero coefficients was rejected at 5% level of significance. Pseudo R-sq is found to be 0.81 in the probit model. This implied the model explains 81% of the variation in willingness to pay. The estimates of the probit regression model also showed that among the ten variables five (training on fish conservation, the distance of respondent’s home from the Lake, experience of respondents, respondent’s land size, and respondent’s total income) were found to be statistically significant in affecting the willingness to pay for catfish species conservation (Table 3). The estimated mean willingness to pay for catfish species conservation of Lake Hawassa from the probit model was 3.62US$ per year (Table 4). Also, from the targeted 256,280 households, the aggregate economic benefit was 954,090.23US$ (Table 5).

Descriptive Analysis

Respondents who showed interest to contribute money for catfish species conservation were 82.5% since there was the problem of: contamination of water in the Lake by different industries, decrement of a catfish species population in the Lake, and lack of proper management of the Lake. Respondents had unwilling to contribute money for catfish species conservation were 17.5%. The main reasons given for this were: (a) proper management is the responsibility of the government, (b) lack of money to pay (poverty), and (c) satisfaction with the current situation.

Econometric Analysis

Factors affecting willingness to pay for catfish species conservation: The results of the probit model were subjected to post estimation test using marginal effect analysis to estimate the trivial change from each factor that influences willingness to pay. Quantification of the marginal effects of these variables is vital to estimate the change that will occur for a change in one unit of that variable. Accordingly, the model results for each significant variables were discussed as follows:

Training on fish conservation: The coefficient for the training on fish conservation had a statistically significant and positive relationship with willingness to pay at 1% significant level. This is consistent with the prior expectation that those respondents who are well trained in fish conservation were more willing to pay than those who didn’t have training on fish conservation. A positive effect of this variable suggested that well-trained respondents are more likely to be efficient in resource allocation, practical use of modern techniques, adoption of improved aquaculture production practices, and use inputs in the right way. The marginal effect result implies that well-trained respondents have a probability of willing to pay which is 8.94×10-3 % greater than those respondents with no fish conservation training. This result implied that investing in the training of respondents is an important mechanism of conservation of catfish species. The result has similar users [18, 21, 22] who understand what the resource is, have a greater appreciation of its importance, and are willing to pay more for conservation.

The distance of respondent’s home from Lake: The coefficient for distance from respondent’s home to the Lake was found to be the expected sign, negative and it is significant at 10% level. This implies that increased distance from the Lake makes the respondents unwilling to contribute to the catfish species conservation program and vice versa. This is because respondents who are at a relatively farther distance from the Lake are assumed to get less access to the fish product as compared to the closer ones and less responsible for managing the catfish. The marginal effect of distance of respondent’s home from Lake implies that as other factors held constant, the distance respondent’s of home from Lake increase by one minute, their probability of willing to pay also decrease by 1.31×107%. This result is in line with the works of Ramanathan B and Belete Z, et al. [22, 23] whereby willingness to pay for conservation decreases as households gets farther away from the resources.

Experience of respondents: The result of the model showed that fishing experience is positively, and significantly at 5% correlated with willingness to pay for the proposed hypothetical catfish species conservation program. The marginal effect result shows that for each additional increase in the year of experience of the respondents, the probability of the willingness to pay for the catfish species conservation will increase by 7.66×10-7 %. The reason for this might be that respondents who have started fishing earlier might have developed good knowledge about the trend of the fishing production system. This is inlined with CSA [25] who reported that fishing experience is positively and strongly significant to the willingness to pay for Lake management.

Land size of respondents: Respondent’s land size was found to be a significant variable at 1% with an expected negative sign. The marginal effect of land size implies that as other factors held constant when the respondent’s landholding size increase by one hectare, their probability of willingness to pay decreases by 1.22×10-5 %. As land size increases, willingness to pay for catfish species conservation may decrease; because they are maybe getting more benefit from their land than the fishery. The result is in line with Nigus HY and Assefa M, et al. [19, 24] who reported that land size had a negative influence on willingness to pay for conservation activities.

Total income of respondents: Total income is also a significant variable at a 1 % level of significance and has an expected positive sign. As the income of respondents increases, their willingness to pay will also increase. The marginal effect showed that when the income raises by one US dollar the probability of willingness to pay for conservation increases by 2.33×10-8 %, other factors remain constant. The implicationis that as the income of the respondent increase, the paying power will also be increased. The result is consistent with Belete Z and Satyanarayana K, et al. [23, 26] who reported that respondents with higher yearly income were more likely to contribute the first bids than households with lower income.

Estimation of mean willingness to pay and aggregate economic benefit: The estimated mean willingness to pay for catfish species conservation of Lake Hawassa was 3.62 US$ per year. Thus, 3.62 US$ estimated from the first equation was used in this study to estimate the mean willingness to pay. From a total of the targeted 256,280 households, the aggregate economic benefit was 954,090.23US$.