Survey of Climate-Related Risks to Tilapia Pond Farms in Northern Thailand

doi:10.4236/ijg.2013.45B009

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International Journal of Geosciences, 2013, 4, 54-59

http://dx.doi.org/10.4236/ijg.2013.45B009 Published Online September 2013 (http://www.scirp.org/journal/ijg)

Survey of Climate-Related Risks to Tilapia Pond Farms

in Northern Thailand

Pornpimol Pimolrat1, Niwooti Whangchai1, Chanagun Chitmanat1, Jongkon Promya1, Louis Lebel2

1Faculty of Fisheries Technology and Aquatic Resources, Maejo University, Chiang Mai, Thailand

2Unit for Social and Environmental Research (USER) Faculty of Social Science, Chiang Mai University, Chiang Mai, Thailand

Email: [email protected]

Received July 2013

ABSTRACT

Climate is an important factor for aquacultur e production. This study aimed to understand how farmers that culture til a-

pia in earthen ponds perceive and respond to climate impacts. Important climate-related risks identified include extr eme

temperatures (hot and cold), excessive rainfall, prolonged cloud cover, flood and drought. Site visits and data collection

using questionnaires were conducted to identify important factors influencing farm profits, losses, decision to increase

or decrease ponds. Special attention was given to knowledge about fish markets and weather and the impacts of weather

and climate on fish growth, diseas e outbre aks and water quality in ponds . Altoge ther 585 fish farms in four prov inces in

northern part of Thailand selected to cover a range of elevations above sea level and thus climate were surveyed (Na-

kornsawan < 100 m, Lampang 100 - 300 m, Phayao 300 - 500 m and Chiang Mai > 500 m). Fish farms at different ele-

vations reported different climate and weather-related impacts. In the area where elevation above sea level is < 100 m,

farmers were affected more by floods and extreme hot weather which caused fish deaths and stress that reduced feeding

and growth rates. Conversely, fish farmers in the area where elevation above sea level is >500 were impacted mainly by

drought and cold weather. These conditions also caused disease outbreaks and reduced feeding rates. Farmers respond-

ed by reducing the amount of feed supplied and considering non-fish pond or non-farm supplementary occupations as

an adaptation strategy. Among non-climate related factors high prices of feed were most commonly identified as a key

issue by farmers. The differences among sites at higher and lower elevation provided insights into the kind of changes

in risks farmers may face as climate changes that could be helpful in developing adaptation strategies for individual

farmers and the sector as a whole.

Keywords: Climate; Tilapia Pond Culture; Aquaculture; Thailand

1. Introduction

Climate is an environmental factor that is strongly asso-

ciated to aquaculture productivity [1]. Being coldblooded

animal, fish is affected by the temperature of the sur-

rounding water which influences the body temperature,

growth rate, food consumption, feed conversion, and

other body functions [2,3]. Over the past few years, ris-

ing global temperatures have received much attention

because of their worldwide impact on ecosystems. The

climate models referenced by the Intergovernmental

Panel on Climate Change (IPCC) [4] predicted that glob-

al temperatures are likely to increase by 1.4˚C to 6.4˚C in

this century.

Nile tilapia (Oreochromis niloticus) is a freshwater

fish of great commercial interest. It is easy to cultur e and

adapts well to a range of environments. Tilapia culture is

one of the largest aquaculture industries in Thailand [5].

In the mountainous northern region, relatively high alti-

tude and latitude contribute to more pronounced seasonal

temperature variation, with cooler winters than in other

regions. Numerous climate variables vary with elevation

[6].

Some farmers rear fish in cages suspended in rivers.

This culture system is sensitive to extreme weather

events, such as floods or droughts [7,8]. It is also sensi-

tive to seasonal differences in water temperature, flow

speeds and water quality. Ponds, however, are the most

common production systems on a worldwide basis. Tila-

pia fish culture in earthen ponds in northern Thailand can

be divided into three categories: commercial, integrated

(with pig or chicke n) and subsistence.

In recent years, production of pond-raised tilapia in

northern Thailand has been hampered by climate-related

risks including extreme temperatures (hot and cold), ex-

cessive rainfall, prolonged cloud cover, flood and

drought all of which potentially cause fish deaths, stress

and reduced feeding and growth rates. In order to better

understand the effects of climate on tilapia pond farms

P. PIMOLRAT ET AL.

this study compared sites along an elevation gradient in

northern Thailand. The specific objective of this study

was to improve understanding of how fish farmers in

different elevation perceive and respond to climate im-

pacts. The differences among sites at higher and lower

elevation provided insights into the kind of changes in

risks farmers may face as climate changes that could be

helpful in developing adaptation strategies for individual

farmers and the sector as a whole.

2. Material and Methods

2.1. Sampling of Fish Farms

A total of 585 fish farmers were interviewed for this

study. The tilapia farmers were randomly selected from

the list of farmers in collaboration with the fisheries of-

ficers of the Department of Fisheries. An effort was

made to interview fish farmers currently or recently hav-

ing reared tilapia in fish ponds in nine provinces in

northern part of Thailand. Not all who had recently

stopped farming could be contacted. Local fisheries offi-

cials, community leaders and private sector feed and

stock suppliers were used to help locate farmers. Almost

all farmers approached agreed to participate in the survey

and were able to answer all questions. Interviews were

carried out using a structure d questionnaire with farmers.

The questionnaire covered individual, farm and site level

characteristics as well as more detailed sections about

impacts from extreme temperatures (hot and cold), ex-

cessive rai nfal l, prol onged cl ou d cove r, fl ood a nd droug ht .

Sites were grouped by provinces into four elevations

for analysis: <100 meters above sea level (masl) (Nak-

honsawan, Pichit, Kamphengphet, Uttaradit and Phitsa-

nulok), 100 - 300 masl (Lampang), and 300 - 500 masl

(Phayao and Chiangrai) and >500 masl (upland areas in

Chiangmai). The characteristic climate of each elevation

are described and summarized in Tabl e 1.

2.2. Data Analysis

The data were compared between elevations for each fish

farm. All reports about difference in this text were sig-

nificant at the P < 0.05 or better level; Tukey HSD tests

were used post-hoc to separate means following detec-

tion of a significant main effect in ANOVA when there

was three or more means.

3. Results and Discussion

3.1. Characteristics of Fish Farmers

The characteristic of the farms and farmers’ obtained

from the present study are presented in Table 2. The re-

sults show that there were more male farmers than fe-

males. Fish farmers were mostly middle-age and had a

primary school level of education. Approximately 30%

of households had a monthly income in the range of

5,000 - 10,000 Thai Baht. The fish farmers’ commonly

had pond-culture experience ranged from 3 - 10 years.

3.2. Climate Impacts at Di f f erent Elevation

The likelihood of climate impacts on farms in different

range of elevation (masl) is shown in Figure 1. Fish

farms at different elevations reported different climate

and weather-related impacts. In the area where elevation

above sea level is <100 m, farms were affected more by

floods (36%) and extreme hot weather (31%). Farms at

elevation above sea level 100 - 300 had higher drought

(35%) problem than other areas. The highest long cloud

cover (51%) impact was foun d in 300 - 500 sites. On the

other hand, fish farmers in the area where elevation

above sea level is >500 were impacted most by extreme

cold weather.

Table 1. Climate in the four study areas (between years 1990-2010). Provinces for which precipitation and temperature data

are shown bel ow are underlined.

Conditions E levation MASL (m)

<100 100 - 300 300-500 >500

Provinces Nakon-swan Kamphengphet Phitsanolok Uttaradit Lampang Phayao Chiangrai Chiangmai

Mean minimum temp in coldest month 18.6 (Jan) 15.7 (Jan) 13.3 (Jan) 12.6 (Dec)

Mean maximum temp in coldest month 37.6 (Apr) 37.9 (Apr) 35.4 (Apr) 27.4 (Apr)

Mean precipitation in wettest month 250.2 (Sep) 218.6 (Sep) 281.2 (Sep) 186.8 (Sep)

Mean precipitation in driest month 4.4 (Jan) 3.9 (Jan) 7.4 (Jan) 3.3 (J an)

Average mean annual precipitation (mm) 1289.4 900.3 1398.9 1233

CV (mean annual precipitation) 0.07 0.47 0.30 0.16

P. PIMOLRAT ET AL.

Table 2. Selected demographic characteristics of the fish farmers (n = 585).

Characteristic Percentage Characteristic Percentage

Age in years Education

<=30 3.6 No formal 4.5

31 - 44 15.7 Primary 60.2

45 - 57 42.7 Lower Secondary 12.6

58 - 71 30.8 Upper Secondary 11.8

72 + 7.2 University 3.8

Household average monthly income (Thai Baht)

Gender

Male 55.9

Female 44.1

<5000 12.8 Pond-culture experience (yrs)

5000 - 9999 30.3 <= 2 7

10000 - 14999 19.3 3 - 10 62.6

15000 - 19999 9.9 11 - 20 19.0

20000 - 29999 12.8 21 - 29 9.2

30000+ 14.5 30+ 2.2

Figure 1. Percentage of climate impacts in different range of

elevation above sea level.

3.3. Effects of Elevation on Culture Type,

Purpose of Culture and Farm Size

Most farmers in northern Thailand cultured tilapia for

consumption (94% of total 585) and many cultured mul-

tiple fish species in ponds (Figure 2(b)). About 47% of

farmers cultured tilapia fish for sale. Commercial farms

were most common at 300-500 masl sites and these sites

also had higher farm size (4+ ponds) than other elevation

sites (Fi gure 2(a) and (b)).

3.4. Perception of Non-Climate-Related and

Indirectly-Related Risks

In present study, w e explored the concern of fish farmers

Figure 2. Percentage of farm size (total ponds) and culture

type of tilapia fish in different range of elevation above sea

level.

about various risk such as disease outbreak, fish theft,

poor feed and fingerling quality, and feed prices. Patterns

of association with elevation varied among risk types.

Fish farmers were most concerned about risks to profita-

bility from low quality fingerlings in all elevation area

(Figure 3). Disease outbreak was of comparatively less

P. PIMOLRAT ET AL.

Figure 3. Level of concern of fish pond farmers over five types of non-climate-related and indir ectly-related risks in four ele-

vations in northern Thailand. Concern was scored on a scale of 1 (not concerned) to 5 (very concerned). Plotted are means

and 95% confidence intervals for the means.

concern relative to other risks in the area where elevation

above sea level is <100 masl and >500 masl. Concern

with feed price and fish theft were lower at the >500

masl elevation site than in other three sites (p < 0.05,

Tukey’s HSD after ANOVA) conversely fish farmers at

300 - 500 masl had highest level of concern about feed

prices.

4. Discussion

Aquatic systems in which animals are reared are directly

influenced by climate. Climate-related risks increase

production costs by making it harder to manage the farm

efficiently and as a result of direct production losses [9].

The climate data from Table 1 indicated that there were

variations in temperatures a mong sites at different elev a-

tions as would be expected. Air and water temperature

are generally cooler at higher elevations [10] and the

temperature of the water is regulated mainly by the tem-

perature of the surrounding air. The importance of dif-

ferent climate-related risks to pond aquaculture varied

with elevation. As elevation increases (>500 masl),

mostly tilapia fish farmers face the extreme cold weather

impact which resulted in reduced feeding and growth due

to the negative effects on the rate of metabolism, chemi-

cal reaction and oxygen consumption [11]. Temperature

is one of the most important environmental factors with

the greatest influence on the growth performance of ani-

mals [12]. Hamdan and colleagues [1] reported that the

significant association between production loss and the

decrease and increase of water temperature indicating

that climate indicators especially temperature is most

influential in the aquaculture production. Water temper-

ature affects the quantity of oxygen dissolved in the wa-

ter, evaporation and aquaculture productivity directly

[13]. The aquaculture species are growing dynamically in

the minimum and maximum tolerance limit of tempera-

ture and survive in optimal temperature. Although tilapia

fish has proven popular for its ease of culture, robustness,

palatability and tolerance of a range of environmental

conditions [5] but these fish do not grow well at temper-

ature below 16˚C and cannot usually survive for more

than a few days below 10˚C [14]. Watanabe [15] re-

ported 25˚C to be the optimum temperature for nutrient

digestibility in tilapia, O. niloticus (L.) and the optimum

temperature for feeding, growth and reproduction is be-

tween 26˚C and 30˚C [16]. Additionally, the highest

P. PIMOLRAT ET AL.

percentage of small farm size (one pond) was also found

in this elevation (>500 masl) one reason possible because

of the unsuitable temperature for culture tilapia fish.

O. niloticus is known to tolerate high temperatu res: up

to 40˚C - 42˚C [17]. However, rapid temperature varia-

tion will have a negative effect on these species growth

due to the less dissolved oxygen in the warm water [12].

The present study clearly showed that farmers growing

fish above sea level, <100 and 300 - 500 masl, were af-

fected more by extreme hot weather than other areas.

Especially, farms at 300 - 500 elevation sites which are

in the highest commercial categories, and the larger farm

sizes (4+ ponds) are usually found in this elevation, the

farmers should be more aware of this important risk be-

cause the association between high temperature and dis-

solved oxygen (DO) have impact on fish production. In

addition, the temperatures above 32˚C may significantly

results in slow growth, reduce feeding efficiency and

increase mortality [12].

Floods are seasonal phenomena happening frequently

during rainy season in certain regions [13]. In 2011,

many areas in Thailand had severe flooding leading to

highest ever damage costs [18]. The present study clearly

showed that the fish farmers at elevation <100 masl

(Nakonswan, Phijit, Kamphengphet, Phitsanolok and

Uttaradit) faced higher impact from floods than in other

regions. According to the flood, many farmers have to

leave their houses, farms, and lose their job therefore

most farms in this site are smaller (one pond) and were

mostly subsistence culture. For reduction and adapting to

this impact, some farmers who cultured tilapia in these

areas changed to culture other fish species for example

Mekong giant catfish (Pangasianodon gigas) or used the

bigger fingering to reduce time of culture per crop. This

strategy will help them minimize the production loss and

ensure that the percentage of new fish stock rises suc-

cessfully and survive in the massive raining season that

occurs at year end. Generally, the impact of drought or

amount of precipitation (Table 1) has been associated

with the volume of water for exchange during culture.

The long drought season and raining fluctuation impli-

cated less DO problem to the pond water [1]. In this

study, the impacts from drought were mostly founded at

100 - 300 masl where highest percentage of poly culture

system has been carried out.

Finally, levels of concern on non-climate risks are as-

sociated between elevation and culture type of fish. It

was found that the unqualified fingering and feed prices

implicated more concerned to culture tilapia fish, espe-

cially at the large commercial tilapia culture of northern

Thailand (at 300 - 500 masl, Phayao and Chiangrai

provinces). To reduce or solve this problem, research in

genetics and selective breeding will be needed to im-

prove pr od uc tion effi c iency.

5. Conclusions

This study showed that the climate-related events and

phenomenon (flood, drought, long cloud cover, and ex-

treme hot and cold weather) to tilapia pond culture var ies

with elevation and culture systems. The extreme cold

weather are mostly presented at >500 masl elevation

where the highest percentage of small farm size (one

pond) was found. On the other hand, the fish farmers at

<100 masl elevation (Nakonswan, Phijit, Kamphengphet,

Phitsanolok and Uttaradit) faced higher impact from

flooding than in other regions. Moreover, the data from

our quantitative survey indicated that low quality finger-

ings and high feed price are factors of high concern to

tilapia farmers, especially at the large commercial tilapia

culture of northern Thailand (at 300 - 500 masl, Phayao

and Chiangrai provinces). The findings of our survey

improve understanding of how fish farmers at different

elevation obtain the climate impacts that could be helpful

in developing adaptation s trategies for individual f armers

and the sector as a whole. Future work should focus on

how farmers manage risks and awareness of climate

change.

6. Acknowledgements

The work was carried out with the aid of a grant from the

International Development Research Centre, Ottawa,

Canada, as a contribution to the AQUADAPT project.

Thanks to the many field assistants, students, officials

and farmers who he lpe d with the surveys.

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