Climate Change Perceptions, Impacts and Adaptation Strategies: Insights of Fishers in Zambezi River Basin, Zimbabwe

Abstract

The Zambezi River Basin is considered to be highly vulnerable to the impacts of climate change and adverse weather events, which might cause serious environmental, economic, and social consequences for millions of people. Therefore, it is crucial to understand how natural resource-dependent people perceive climate change, and how they adapt to the changes, as it is very important for climate change adaptation policy formulation and its implementation. Therefore, this study seeks to assess fishers perceptions of climate change, its impacts on fishery resources and livelihoods, and their adaptation strategies. Data were collected from 120 fishers in two basins (Binga and Kariba) along the shores of Lake Kariba using a mixed-method research approach. Meteorological data were obtained from the Meteorological Department Services of Zimbabwe (MSDZ). The findings show that fishers of Lake Kariba have observed changes in temperature and rainfall trends. Fishers believe that the perceived changes of the climatic variables have led to a decline in fish productivity and fish catches. To cope with declining fish stocks and catches, fishers have adopted several adaptation strategies, including changing fishing gear, targeting new fish species, and increasing fishing efforts. These study findings help to set a path towards local specific climate change adaptation strategies for small-scale fishers. This study provided relevant information for policy makers and fisheries stewards to formulate appropriate policies and programmes aimed at enhancing fishers adaptation to climate change and promote sustainable fisheries.

1. Introduction

Climate change is a significant global phenomenon threatening all aspects of human development and environmental sustainability, making it an issue of pressing political and social concerns. The Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report confirms and supports the notion that climate change and variability pose significant economic, social, and environmental threats globally [1]. Near surface temperatures in most parts of Africa have increased by 0.5 °C in the past five to ten decades, with minimum temperatures increasing faster than maximum temperatures [2]. In addition, climate projections indicate that Africa’s temperature is expected to rise faster than the global average increase during the 21st century [2]. In southern Africa, climate models project an increase in temperature of between 3.4 °C and 4.2 °C above the 1981–2000 average under the A2 scenario (greenhouse gases emissions increasing due to change land use caused by high population growth and less rapid increases in agricultural productivity) towards the end of the 21st century [2]. Due to a lack of sufficient observational data across most parts of Africa, it is a challenge to draw robust conclusions on Africa’s annual rainfall trends over the past decades [2]. However, in areas where there is sufficient data, such as the Sahel, North Africa, and southern Africa, a decline in annual precipitation has been observed [2]. Furthermore, climate projection models such as the Coupled Model Intercomparison Project Phase 5 (CMIP5) projects a very likely decrease in annual rainfall in most parts of Africa, including Southern Africa, West Africa, and Northern Africa in the 21st century [2]. Nangombe et al. [3] state that the African continent has experienced a plethora of recording-breaking extreme weather events such as cyclones, floods, and droughts. In a study conducted by Gizaw and Gan [4], the General Circulation Models (GCMs) indicate that the frequency of short droughts is projected to increase by four to seven percent in the central, eastern, and southern parts of Africa between 2050 and 2080 [4,5]. Natural ecosystems, livelihoods and the food and nutrition security of people dependent on climate sensitive resources will be severely affected by the observed and projected changes in climate trends and the increased incidence of extreme weather events.

The fisheries sector that supports livelihoods, generates jobs, and ensures food and nutrition security for millions of people in rural sub-Saharan Africa (SSA) is highly susceptible to climate change. Mohammed and Uraguchi [6] argued that climate change and variability pose the most significant threat to fisheries more so than other stressors because they interact and amplify the existing non-climatic stressors. Gownaris et al. [7] and Kolding et al. [8] also indicate that fish production is more dependent on the external climatic drivers than on management interventions and human exploitation rates, especially inland freshwater fisheries. The World Forum of Fisher Peoples (WFFP) stipulates that water bodies that support inland freshwater fisheries are experiencing warming water, increasing salinity and decreasing water levels due to climate change [9]. These climate change impacts threaten freshwater species, fish habitats, and fishing grounds. For instance, studies by Ndebele-Murisa et al. [10]; Cohen et al. [11] and Nyboer and Chapman [12] indicate that elevated temperatures affect fish physio-chemical and biological processes such as metabolic rates, growth, and reproduction. Ndebele-Murisa et al. [10] and Cohen et al. [11] postulate that increasing temperatures due to climate change has significantly contributed to declining fish productivity in the Kariba and Tanganyika lakes, respectively. In addition, extreme weather events due to climate change and variability disrupt fishing schedules, destroy fishing infrastructures such as fish landing sites and fishing boats, and cause harm and loss of lives [13,14]. Generally, climate change scenarios project that maximum catch potential might decrease by 2.8% to 5.3% and 2.8% to 4.3% under RCP2.6 by 2050 and 2095 relative to 2000, respectively [15], indicating that climate change will adversely affect nations and communities that are dependent on natural resources for livelihood and food. However, climate change and variability in fisheries vary across nations, regions, fishing communities, and households.

The significant effects of climate change on fishery resources, such as declining fish productivity and the disruption of fishing schedules, are expected to result in profound impacts on the economic and social wellbeing of fishers [16]. The literature shows that fishers have adopted several strategies to safeguard their livelihoods and food security. Martins and Gasalla [17] state that fishers are able to adapt and cope with new conditions. In Malawi, some fishers on Lake Chilwa have diversified their livelihoods to farming and pastoralism, while others migrated in response to the decrease in fish catches [18]. In Lake Wamala in Uganda, fishers diversified livelihoods, targeted new fish species, increased fishing time, changed fishing gear, increased fishing effort and changed fishing grounds to deal with declining fish catches resulting from climate change [13]. However, adaptation practices are location-specific and are determined by specific local knowledge and conditions.

Traditionally, climate change observations and projections, particularly at global and regional scales, have been primarily based on meteorological data and climate models such as GCMs [19]. Randall and Wood [20] argue that GCMs provide credible quantitative estimates of the current and future climate change, particularly at larger scales, i.e., continental and global scales. Despite the capability of GCMs to provide good simulations of general atmospheric circulation at larger scales, they do not capture the finer detail required for local (national or community level) climate change assessments [21]. However, reliable climate change information at finer spatial scales is required to formulate local adaptation policies to deal with the effects of climate change and variability [21].

Boillat and Berkers [22] state that the ability to observe and ascribe meaning to changes in the occurrence of weather phenomena and their intensity is an important starting point for the capacity to adapt to climate change. Therefore, understanding how small-scale fishers conceptualize climate change, its effects on fisheries and their adaptation strategies to the effects of climate change is crucial for the development of climate change management actions and adaptation policies. Fishers’ observations of local climatic conditions and peculiarities are crucial to understanding micro level climate change, which is often difficult to detect with climate models, and they also help to understand the changes in climatic trends where historical data is missing [17]. For instance, Musinguzi et al. [13], Chen [23] and Hasan and Nursey-Bray [24] used fisher’s perceptions to document the perceived changes in climatic conditions and their impacts on fisheries and the livelihoods of fishing communities.

Several studies such as Musinguzi et al. [13]; Limuwa et al. [25]; Hasan and Nursey-Bray [24]; Martins and Gasalla [17]; Chen [23] have been conducted globally and within the sub-Saharan Africa region, assessing fishers’ perceptions of climate change and their adaptation strategies. Muringai et al. [26] assessed the fishers’ perceptions of climate change and their consequences on small-scale fisheries in Lake Kariba but did not assess the adaptation strategies used by the fishers to deal with the consequences of climate change. Hence, there is a paucity of knowledge on fishers’ perceptions of climate change and their adaptation strategies in Lake Kariba. Against that backdrop, this study seeks to assess the small-scale fishers’ perceptions concerning trend changes of climatic factors and adverse weather events, impacts on fish resources and catches, and fishers’ adaptation strategies. The study focuses on fishers as an integral part of the ecosystem, as their perception of the changing environment plays a crucial role in formulating climate change-centered adaptation and mitigation actions for the present and future. The study was conducted in two rural districts (Binga and Kariba) found on the shores of Lake Kariba in Zimbabwe, mainly because it has been acknowledged to be vulnerable to climate change, and fisheries are one of the primary sources of livelihoods and food and nutrition security in the area [27].

2. Materials and Methods

2.1. Study Area

Lake Kariba is the third-largest man-made lake in the world, measuring about 276 km in length, with an average depth and width of 29 m and 19 km respectively [28]. The lake lies along the Zambezi River, bordering Zambia and Zimbabwe (16.5221° S, 28.7617° E) (Figure 1). On the Zimbabwean side, the lake is divided into five hydrological basins, namely Binga, Mlibizi, Sanyati, Sengwa, and Ume [28,29]. The construction of Lake Kariba along the Zambezi River led to the development of the fishing and tourism industries along the lakeshores benefiting the district [30]. According to Ndhlovu et al. [29], there are six fishing camps and thirty-five fishing villages along the shores of Lake Kariba. Small-scale fishing is the main livelihood strategy in these areas, as all the camps and villages are within protected wildlife areas. The Statutory Instrument 360 of 1990 prohibits livestock rearing and farming in these protected areas [29].

This study mainly focused on two basins, Binga in the Binga Rural District (BRD) and Sanyati in the Kariba Rural District (KRD) (Figure 1). The Binga district is in Matabeleland, a northern province of Zimbabwe. Despite being regarded as one of the country’s poorest districts, BRD is endowed with vast natural resources that include wild animals, hot springs, timber, and the mighty Zambezi River waters [31]. The district is semi-arid with a tropical dry savannah climate [32], is characterized by a low and erratic rainfall of less than 600 mm per annum, and records high mean annual temperatures of about 30 °C [33]. According to Mago et al. [31], BRD is well known for inhospitable climate conditions, making it a drought-prone area. Conyers [30] states that most parts of BRD are not suitable for agriculture, since temperatures are high and rainfall is generally low and erratic. On the other hand, KRD is found in the Mashonaland West province of Zimbabwe. The climate of KRD is predominantly semi-arid [10] and characterized by mean annual rainfall of approximately 700 mm with a high rainfall recorded during the rainy season (October–March). Additionally, the mean annual minimum temperature and the mean annual maximum temperature are about 24 °C and 30.7 °C, respectively. Most of the people in KRD are directly or indirectly involved in fisheries as a full-time or part-time activity.

2.2. Data Collection

This study is based on both primary and secondary datasets collected from a survey of fishing households in BRD and KRD and the Meteorological Services Department of Zimbabwe, respectively. Semi-structured questionnaires assessing fishers’ observations, interpretation of changes in climatic trends, impacts of climate change on fisheries and adaptation strategies to changing conditions were administered to the fishing households in KRD (November to December 2018) and in BRD (November to December 2020). A total of 120 household heads in fishing communities were purposively selected to participate in the study, with 55 from Binga and 65 from Kariba. Fishers were selected based on their availability and willingness to participate in the study. The participants’ selection criteria were based on the involvement in fishing and its related activities, the household head, and permanently residency in the study areas.

Table 1. Socio-economic demographic profiles of fishers.

Household Characteristic		Study Areas		Total (n = 120)	Percentage (%)
		Binga (n = 55)	Kariba (n = 65)
Age	<20	1	3	4	3.3
	21–30	4	6	10	8.3
	31–40	11	24	35	29.2
	41–50	13	26	39	32.5
	51–60	19	4	23	19.2
	>60	7	2	9	7.5
Gender	Male	43	49	92	76.7
	Female	12	16	28	23.3
Marital Status	Never Married	4	11	15	12.5
	Married	43	51	94	78.3
	Divorced	1	-	1	0.8
	Widowed	7	3	10	8.3
Education Level	Never attended	5	9	14	11.7
	Primary school	12	14	26	21.7
	Secondary school	38	41	79	65.8
	Tertiary	-	1	1	0.8
Household Size	1–3	5	9	14	11.7
	4–6	31	44	75	62.5
	7–9	16	11	27	22.5
	>9	3	1	4	3.3
Period of Stay in the Area	<5	-	1	1	0.8
	6–10	3	7	10	8.3
	11–15	10	11	21	17.5
	16–20	8	16	24	20
	21–25	6	9	15	12.5
	26–30	5	11	16	13.3
	31–35	10	8	18	15
	>35	13	2	15	12.5
Household dependents	0	6	13	19	15.8
	1–3	10	11	21	17.5
	4–6	13	7	20	16.7
	>6	26	34	60	50

shows the socio-economic demographic information of the fishers who participated in this study.

Fishers were asked (1) whether they had observed changes in temperature, rainfall, and frequencies of extreme weather events (drought and floods); (2) and if they had observed any changes, what changes they had observed; (3) the perceived consequences of these changes on fisheries; and (4) the adaptation strategies adopted to deal with the effects of climate change. Furthermore, eight key informant interviews were conducted with Lake Kariba Fisheries Research Institute (LKFRI) ecologists, traditional leaders, and village elders.

For triangulation purposes, four focus group discussions (FGDs) were held to share, validate, and explore the household survey findings and key informant interviews in greater detail [19]. The FGDs were made up of six to ten people, of which two discussions had mixed genders, one was only male and one had only female participants. FGDs with separated genders were done to ensure that female participants fully participated and expressed their perceptions without male intimidation, as in some cultures women are not allowed to talk in the presence of male counterparts. Lastly, meteorological time-series data (temperature and rainfall) was obtained from the Meteorological Services Department of Zimbabwe (MSDZ). The time-series data was used to validate the perceptions of respondents about climate patterns and trends.

2.3. Data Analysis

Data collected through the household survey questionnaire were coded by assigning numerical codes to the responses. The IBM SPSS Statistics version 27 was used for statistical analysis. Frequencies and percentages were mainly used to summarize the gathered household and perception information. The meteorological data were subjected to linear trend analysis using Microsoft Excel (2016). Furthermore, the multinomial logistic regression model was used to analyze the socioeconomic factors and perceptions influencing the fishers’ choices of adaptation strategies to climate change [34]. In this model, the dependent variable was multinomial, with several categories based on the climate change adaptation strategies identified in past studies. The model can be reduced to the following Equation (1):

Yi = f(X1, X2, X3…….,X6)

(1)

where, Yi, the dependent variable, represents the climate change adaptation strategies selected by the fishers. In this case, the dependent variable (Yi) is coded 0 for “change fishing gear,” 1 for “targeting new fish species,” 2 for “increasing fishing time/days (increasing the number of days the fisher practices fishing activities),” 3 for “diversifying livelihoods,” 4 for “increasing fishing effort (increasing fishing gear e.g., boats and nets),” 5 for “migrating to new fishing communities,” and 6 for “no adaptation”. X1 to X6 are explanatory variables that affect the fisher’s choices. X1 = age, X2 = gender, X3 = marital status, X4 = education level, X5 = fisheries experience and X6 = fisher’s perceptions. The “no adaptation” category was used as the base category to estimate the model of multinomial logical regression in this study.

Table 2. Description of explanatory variables included in the regression model.

Explanatory Variables	Coding	Category
Age	Years	Continuous
Gender	0 = male, 1 = female	Dummy
Marital status	0 = married; 1 = otherwise	Dummy
Education level	0 = formal education; 1 = no formal education	Dummy
Fishing experience	Years	Continuous
Perception of Climate Change	0 = knowledgeable; 1 no knowledge	Dummy

describes and summarizes the variables used in the model.

The qualitative data gathered through key informant interviews and FGDs were transcribed and translated to English and analyzed using content analysis by identifying recurring themes, trends, and keywords [19,25]. Data were then classified into different themes based on fishers’ perceptions of climate change, climate change impacts on fisheries and livelihoods, and the fishers’ adaptation strategies. Some fisher’s responses were also quoted in the study.

2.4. Ethics Statement

The University of KwaZulu Natal approved the study, and an ethical clearance certificate, reference number HSSREC/00003055/2021 was granted by the Humanities and Social Sciences Research Ethics Committee (HSSREC). Permission to carry out the study was granted by the Zimbabwe Ministry of Local Government, Public Works, and National Housing in 2020. Fishers’ participation in the study was voluntary, and all participants gave verbal informed consent to participate in the study.

3. Results

3.1. Socio-Economic Profile of Respondents

A total of 120 fishers in two districts, Binga and Kariba, which are located along the shores of Lake Kariba, participated in this study. The socio-economic characteristic of fishers across the two districts were collected, tabulated, analyzed, and presented in Table 1. The age distribution of the fishers shows that the majority (32.5%) of the fishers who participated in the study were aged between 41 and 50 years, followed by the 31 to 40 age group, which constituted about 29% of the participants. Fishers who were above 60 and below 20 years of age were represented least, accounting for 7.5% and 3.3% of the total fishers who participated in the study. The majority of the study participants were males (76.7%), and females constituted 23.3% of the participants, and most (78.3%) of the fishers were married and less than 1% (0.8) divorced. The literacy levels of respondents were found to be very high, with more than 85% of the respondents having attended formal education, which can be either primary, secondary, or tertiary. Furthermore, 62.5% of the fisher’s households were comprised of four to six members and only 3.3% of the households had more than nine members. Approximately 80% of the respondents had stayed in the areas under study for more than 10 years. The study areas are characterized by high household dependent ratios, as about 50% of the households had more than six economically dependent people.

3.2. Fishers’ Perceptions of Changes in Climate Trends and Extreme Weather Events

Fishers were asked if the climatic variables in their respective communities have changed over the past 10 years. The findings indicate that 83.8% of the fishers believe that temperature has increased during the past 10 years (

Table 3. Fisher’s perceptions of changing climate trends over the past 10 years.

Climate Parameters	Participant’s Response
	Increase (%)	Decrease (%)	No Change (%)	Do Not Know (%)
Temperature	83.8	11.9	4.3	-
Rainfall	5.6	76.3	6.3	11.8
Frequency of floods	56.9	12.5	21.9	8.7
Frequency of droughts	63.1	18.1	3.8	15
Surface water levels	25	37.5	30.6	6.9

). During the FGDs, some of the fishers in Binga District mentioned that:

When it comes to the issue of temperature and rainfall, everything has changed in the past 10 years. The weather was not as bad as it is now. The temperatures are very high throughout the day, and they are few cold days even during the winter season which is different from what we used to experience in the past …

(Male, Binga District)

We have already started experiencing hell on earth, in the past few years, from around August to March we are experiencing extreme hot days. Now I must wake up very early in the morning to cast my fishing nets because by eight in the morning it will be hot already …

(Male, Binga District)

Fishers from the Kariba District also perceived that the temperatures in their area were getting warmer, as the following statements show:

The temperature has drastically increased in the past 10 years, the summer season has just become too hot, and I am starting to worry about how it is going to be in the next five to ten years from now …

(Male, Kariba)

Some days are just becoming too hot for me. If I remember well in the past few years, we were not experiencing hot days as we are experiencing today …

(Female, Kariba)

The majority of the fishers (76.3%) believe that the amount of rainfall received in their respective areas has decreased during the last 10 years. Results from the FGDs also show that fishers from both districts believe that rainfall has declined and is becoming more unpredictable. Some fishers expressed that:

The way it is hot these days we also expect good rains. We used to know that if we have two or three consecutive hot days then it rains but nowadays it can be hot for several days or weeks without a single drop of rain …

(Female, Kariba District)

We used to receive considerable amounts of rainfall usually from late October to March but now September and October are usually dry, and we receive little rainfall maybe towards the end of November. Generally, the amount of rainfall is decreasing that’s why we are experiencing a lot of drought seasons

(Male, Kariba District)

This area is in the low veld region, and it is generally characterized by low rainfall, but in recent years our area is becoming drier and drier, rainy days have decreased and when it rains the rainfall is not enough to fill up the lake or sustain our crops …

(Female, Binga)

In addition, a key informant in Binga mentioned that:

The rainfall patterns in this area are becoming more and more unpredictable as we can have long periods of little rainfall causing serious drought situations, and then sometimes we get rainfall of high intensity we usually cause flooding. However, from my personal experience, the area is becoming dry, there is a noticeable decrease in the amount of rainfall received …

(Male, Binga)

Extreme weather events are common features in the study areas. Most fishers (63.1%) indicated that in the past 10 years there has been an increase in the occurrence of droughts, with 56.9% indicating that the occurrence of floods has increased, and 37.5% perceiving that the lake water level has decreased (Table 3). A key informant and a fisher said that:

The water level is always fluctuating with the low water level being very common during the winter season and the level increasing during the rainy season. In recent years, the water level is no longer reaching the higher levels it used to reach in the previous years which might be associated with low rainfall and high evaporation due to increasing temperatures …

(Key Informant, Kariba)

In the past few years, the water level is not rising as it used to during most rainy seasons. During the rainy season, the water level used to rise and cover all those small shrubs close to the banks of the lake …

(Male, Binga)

The statements in the group discussions generally corroborated with most responses from the household questionnaires, as the fishers emphasized increasing temperature, declining and unpredictable rainfall patterns, increasing occurrence of droughts, and decreasing surface water level (Table 3). However, the nuanced views on floods seen in the household interviews were not repeated in the group discussions, where fishers did not agree on an increased incidence of floods.

3.3. Empirical Evidence of Climate Variability and Trends

The perceptions of fishers about the observed trends of climate variables in the past 10 years were compared with meteorological time series data, and correspondences were confirmed on perceptions about the temperature in both study areas. Congruent to the fishers’ perceptions of increasing temperatures, the results from the temperature historical data show an overall increase in temperature between 1987 and 2017 (Figure 2), but the increase is insignificant in both Binga (R² = 0.0004, p > 0.05) and Kariba (R² = 0.0015, p > 0.05) (Figure 3). Figure 3 shows a variation in the mean annual temperature over the 1987–2017 period. The temperature anomalies in Figure 3 show a slight increase in temperature in both study areas reflecting warming temperatures. The temperatures were warmest in 2002 in both Binga (28.2 °C) and Kariba (27.3 °C), and the lowest below-average temperatures were recorded in 2011 (23.6 °C) in Binga and 2013 (23.3 °C) in Kariba.

The meteorological data confirmed the fisher’s perception of decreasing rainfall for the BRD (Figure 4). Figure 4 shows that the total annual rainfall in BRD decreased between 1987 and 2017. Contrary to the fishers’ perception of declining rainfall in KRD, the meteorological data shows a perceptible increase (about 30%, R² = 0.3091, p < 0.05) of rainfall in Kariba, and the period 2004–2007 is characterized by above-average rainfall (Figure 5). Figure 5 depicts annual rainfall variation for BRD and KRD between 1987 and 2017, which had a mean annual rainfall of 532.7 mm/year and 689.3 mm/year, respectively. The study areas were characterized by highly variable rainfall patterns between 1987 and 2017, as shown by the rainfall anomalies (Figure 5). Between 1987 and 2017, BRD was mainly characterized by below-average rainfall (below 532.7 mm. year), particularly between the years 2000 and 2016. KRD was mainly characterized by above-average rainfall (above 689.3 mm/year) between 1987 and 2017.

3.4. Observed Weather Changes and Their Impacts on Fisheries

Fishers and key informants were aware of the effects of climate change on fisheries and human wellbeing. Climate change has generally led to a decline in fish production in most freshwater fisheries in the sub-Saharan Africa region. Based on results shown in Figure 6, 63.3% of the fishers indicated that climate change has resulted in declining fish stocks. Most fishers (58.5%) reported changes in fish species composition, 45.3% indicating an increase in invasive species due to climate change. The decline in fish stocks owing to climate change has led to a decrease in profits obtained from fisheries, as indicated by 55.3% of the fishers. Fishers also perceive that the shrinking of fishing grounds and food insecurity is a result of climate change, as indicated by 49.3% and 76% of the fishers, respectively (Figure 6).

In the FGDs, changes in rainfall and temperatures patterns were perceived as the main climatic factors affecting the fisheries sector as a whole. However, most fishers expressed more concerns about the declining total amount of rainfall than increasing temperatures, as the following statements show:

I have been fishing in Lake Kariba for more than 30 years now and over time I have noticed that the amount of rainfall we used to receive has declined to cause the lake water level to decline and small water bodies close to our community are drying up. Our prescribed fishing grounds are shrinking due to disappearing surface water resulting in reduced fish catches for us. I used to catch lots of fish in a day and now I have to fish for three or four days to get the same amount I used to get in a day …

(Key informant, Kariba)

I am a full-time gill net fisher and climate change, particularly changes in rainfall patterns have affected my fishing profits. Fish come with rains, but in the past years, the rainfall is too little to increase fish availability. During the rainy season, my fish catches used to be amplified but that is no longer the case these days …

(Male, Kariba)

The rain has become more unpredictable, and the rainy season is now shorter which is affecting our overall food security situation. Fish is our main source of animal protein and now we are catching less of it if we eat most of the catch, we won’t have a surplus to sell. Droughts are affecting our crops as well; we are not harvesting enough crops to sustain us for the whole year …

(Female, Binga)

3.5. Adaptation Strategies of Fishers in Response to Changing Climate

Fishing is the main occupation for all study participants. The high degree of dependence on fishing activities requires major adaptation measures, as the sector is directly affected by climate change. The study findings in

Table 4. Adaptation strategies adopted by fishers.

Strategies	Frequency (n = 120)	Percentage (%)
Change fishing gear	51	42.5
Targeting new fish species	24	20
Increasing fishing time/days	53	44.2
Diversifying livelihoods	17	14.2
Increased fishing effort	54	45
Migrating to a new fishing community	9	7.5

NB: Fishers can adopt more than one adaptation strategy.

show that fishers adopted a range of practices in response to the perceived effects of climate change on fisheries. The most common responses indicated by the fishers included increasing the fishing effort (45%), increasing fishing time/days (44.2%), changing fishing gear (42.5%), and targeting new fish species (20%) (Table 4). Other responses included diversifying livelihoods (14.2%) and migrating to new fishing communities (7.5%). However, the type of adaptation strategies used by fishers is influenced by several socioeconomic factors and perceptions of climate change.

The multinomial logistic regression (MNLR) model was used to estimate the effect of socioeconomic characteristics and perceptions on the fishers’ decision to select climate change adaptation strategies. The results indicate that the fishers’ experience positively and significantly influenced the adoption of all adaptation strategies except livelihood diversification (n = 120; 1.257, p > 0.05) (

Table 5. Socioeconomic and perception determinants of climate change adaptation strategies adopted by fishers.

Variable	Change Fishing Gear		Targeting New Fish Species		Increasing Fishing Time/Days		Diversifying Livelihoods		Increased Fishing Effort		Migrating to a New Fishing Community
	Coeff.	Sig. (p-Value)	Coeff.	Sig. (p-Value)	Coeff.	Sig. (p-Value)	Coeff.	Sig. (p-Value)	Coeff.	Sig. (p-Value)	Coeff.	Sig. (p-Value)
Age	−1.687	0.215	−1.632	0.207	1.577	0.304	4.203	0.035 *	0.771	0.052	0.020	0.892
Gender	−0.002	0.996	0.232	0.564	0.603	0.139	0.128	0.257	0.888	0.030 *	−0.055	0.257
Marital status	0.129	0.638	0.037	0.895	0.049	0.224	0.290	0.063	−0.014	0.771	−1.607	0.230
Education level	1.708	0.048 *	0.218	0.721	0.153	0.812	2.249	0.009 *	1.747	0.068	0.0153	0.670
Experience	0.314	0.006 *	0.323	0.004 *	0.384	0.001 *	1.257	0.066	0.331	0.004 *	−3.345	0.072 **
Perception on CC	0.029	0.415	1.755	0.040 *	0.183	0.877	2.300	0.007 *	2.211	0.010 *	−0.004	0.927
Base category Total number of observations Likelihood ratio Chi2 Log Likelihood	No Adaptation 120 141.564 −123.567

Significance at * 5% and ** 10% probability level, respectively, Likelihood ratio Chi² = model goodness of fit (p < 0.05).

). Moreover, the results show that the level of education positively and significantly affected the fishers’ decision to change their fishing gear (n = 120; 1.708; p < 0.05) and to diversify their livelihoods (n = 120; 2.249; p < 0.05). Table 5 shows that the fishers’ perceptions of climate change positively influenced their decision to target new fish species and diversify livelihoods as climate change adaptation strategies, showing a statistical significance of n = 120; 1755; p < 0.05 and n = 120; 2.300; p < 0.05, respectively (Table 5).

4. Discussion

4.1. Fishers’ Perceptions of Climate Change and Variability

Fishers are aware of climate change and there is consensus that temperature and rainfall trends have changed over the past decade. These findings are in line with Dube and Nhamo [35]; Mahere et al. [36], and Ndebele-Murisa et al. [37], findings that also detected increasing temperatures in areas around Lake Kariba. According to Ndebele-Murisa et al. [37], in the past decades, temperatures in areas surrounding Kariba have been rising at a faster rate than the IPCC regional projections for the semi-arid regions of Africa. Furthermore, studies by Martins and Gasalla [17] and Hasan and Nursey-Bray [24] also report that fishers perceived an increase in temperature in the South Brazil Bight and coastal Bangladesh, respectively. This increasing temperature trend is of great concern, as several studies such as Cohen et al. [11], Gobler et al. [38], and Harrod et al. [39] have demonstrated that increasing water temperatures, caused by increasing air temperatures, bear adverse impacts on freshwater ecosystems’ fish productivity.

The linear regression analysis of rainfall data (Figure 4 and Figure 5) validates the fishers perceived decrease in the total amount of rainfall received in BRD and not in KRD. The fishers’ perceptions are reinforced by Magadza [40] and Ndebele-Murisa et al. [10] whose study findings revealed that rainfall in the Zambezi valley is decreasing by between 1 to 6 mm per decade. However, the disparities between the results from the linear regression analysis of the rainfall data in this study and Ndebele-Murisa et al. [10] and Magadza [40] might be attributed to the differences in periods analyzed. For instance, this study’s findings indicate that total annual rainfall increased between 2003 and 2017, while Ndebele-Murisa et al. [10] analyzed rainfall data from 1964 to 2008. Contrary to this study’s findings, a study by Muchuru et al. [41] on the variability of rainfall over the Lake Kariba catchment area in the Zambezi River basin, which includes BRD and KRD, revealed a normal distribution of rainfall across the catchment area. On the other hand, findings by Hasan and Nursey-Bray [24] indicate that most fishers in Bangladesh observed increasing rainfall over the past decades. The differences between the two findings might be attribute to the geographical locations of the study areas, as the ZRB is in the southern hemisphere and Bangladesh is in the northern hemisphere, which are characterised by different climates.

The government of Zimbabwe (GoZ) postulated that Zimbabwe is susceptible to periodic droughts attributed to El Nino events [42]. In the current millennium, devasting droughts were experienced in 2001/02, 2002/03, 2004/05, 2006/07, 2011/12, 2015/16, and 2018/19 [42,43,44]. These recurrent drought episodes, coupled with variable rainfall patterns have caused water levels to fluctuate in Lake Kariba [44]. This supports the fishers’ perceptions on increased drought occurrence and decreasing surface water levels.

4.2. Perceived Impacts of Climate Change and Extreme Weather Events on Fisheries

Understanding the perceptions of fishers about the effects of climate change and adverse weather events is an important basis on which to build climate change adaptation and mitigation measures. This study found that fishers in Lake Kariba agreed that changing climatic trends and extreme weather events owing to climate change have affected the freshwater ecosystem and the livelihoods of the fishery-dependent households. Several studies found that drought events can have severe effects on freshwater fisheries such as disturbing fish habitats [45,46], fish physiological functioning [47], spawning [48], and fish assemblages [49]. For instance, the decline in the Nile tilapia in Lake Wamala (Uganda), was associated with reduced lake levels since the 1980s due to droughts, which may have created unfavorable conditions that reduced the volume and area of open water habitat, reducing breeding and nursery areas [13]. Lake water levels decrease due to persistent low rainfall and drought events, which affect fish production. Maulu and Musuka [50] have stated that the decline of Lake Kariba’s water level in 2014 led to the sudden decline observed in the annual production of fish, as measured in metric tonnes.

Furthermore, fishers perceived that floods caused damage to fishing gear, disrupted fishing schedules, and sometimes lead to injuries or loss of lives. These findings correspond to those of Musinguzi et al. [13] and Westlund et al. [14], who reported that floods damaged fishing boats, fishing gear, damaged landing sites, and reduced fishing days in Uganda and caused loss of lives in Indonesia, respectively. Additionally, fishers in Tam Giang Lagoon, Vietnam state that floods damage their fixed fishing gear, such as bottom nets and coral nets [51]. However, injuries and the loss of lives of fishers in Lake Kariba are associated with strong winds that increase the severity of waves, for instance, the most violent wave locally known as the “Binga wave”, which capsizes boats leading to drowning and loss of life. On the other hand, research indicates that floods recharge the water bodies, thereby increasing the surface water level which provides the habitat for fish production. This causality was observed by Njaya et al. [18] in lake Chilwa and Mboya [52] in Mbita division-Homa bay county in Kenya.

Fishers in Lake Kariba could not associate changes in temperature to any direct effects on fisheries. However, research shows that temperature drives most of the biological and physio-chemical processes in aquatic environments [39]. Ficke et al. [53] state that all freshwater fish are exotherms that cannot regulate their body temperature through physiological means and their body temperatures are almost identical to their environments. Since freshwater fishes are ectotherms, warming temperatures can elevate physiological functions and increase metabolic demands, which directly affects productivity, growth, reproductive success, thermal tolerance, and food consumption [5,11,47,53,54,55]. For example, a study by Nyboer and Chapman [12] which investigated the effects of elevated temperatures and acclimation time on the Nile perch (Lates niloticus) of Lake Victoria found that exposing Nile perch fish to increasing temperatures for three weeks resulted in reductions in the standard metabolic rate of the fish, consequently affecting the growth rate. In addition, warming temperatures affect primary productivity and plankton abundance in freshwater ecosystems. Primary productivity and plankton abundance has declined in several African great lakes including Kariba, Kivu, Malawi, and Tanganyika [5,37]. Ndebele-Murisa et al. [10] found that warming water temperatures led to a decline in Kapenta (Limnothrissa miodon) fish catches. Hence, the perceived declining fish stocks and fisher’s catches in Lake Kariba can be associated with the observed increasing temperatures.

Besides playing a crucial role in recharging lake water, rainfall plays a significant role in transporting nutrient-supplying sediments into the lake [56], which is a source of fish feed. Bootsma et al. [57] postulate that high rainfall brings nutrient fluxes into lakes through rivers. Nutrient availability in the lake enhances fish production. Therefore, despite the increasing trend in the rainfall meteorological data of KRD, the perceived change in rainfall patterns affects fish production. Fishing is the primary livelihood and source of food for the fishers in BRD and KRD, hence the changing environment and declining fish resources led fishers to adapt and develop strategies to deal with the effects of climate change.

4.3. Adaptation Strategies of Fishers in Response to Changing Climate

Fishers of Lake Kariba interpret and react to climate change impacts in different ways based on the perceived effects of climate change on fishery resources, which may help them to cope with the impending changes. This study’s findings show that fishers of Lake Kariba demonstrated the capacity to adapt to the declining fish abundance, changing fish species composition, and reduced fish size. Increasing fishing effort and fishing days might be the most beneficial adaptation strategies for the fishers to deal with declining fish catches. Sanders and Morgan [58] defined fishing effort as the product of fishing power and the number of unit operations and is, therefore, the total effective area covered by the gear during a number of unit operations. In Lake Kariba, fishers have increased their fishing gear to increase their fish catches. This finding coincides with Nyamweya et al. [59] who found that fish catches in Lake Victoria increased with increasing fishing effort. However, the increasing fishing effort strategy may be beneficial for a short period but have detrimental effects on fish abundance in the long run, thereby jeopardizing the capacity of fish resources to sustain fishers’ livelihoods and food security.

Fishers of Lake Kariba changed their fishing gear to deal with the change in fish species composition and reduced fish sizes. A study by Karenge et al. [60] indicated that the fish species composition in Lake Kariba was changing. Fish species such as the C. gariepinus, Labeo spp. and Distichodus spp., which were the abundant species in the 1960s have declined rapidly, and now the S. zambezenis seems to be most abundant fish species [60]. Most of the fishers in the surveyed communities are gillnet fishers who use nets to catch fish. However, small scale fishers of Lake Kariba mainly target Oreocromis niloticus, H. vittatus and T. rendalli fish species due to their economic and diet significance. Changing fishing gear is a widely used strategy used by several fisheries across the globe to deal with dwindling fish stocks. For instance, Makwinja et al. [61] found that fishers in Lake Malombe in Malawi changed their fishing gear to cope with the declining fish stocks. In Lake Wamala, the mesh size of gillnets, which are the dominant fishing gear used by small-scale fishers, dropped from 88.9 mm to 38.1 mm [13]. Furthermore, McLean et al. [62] also reported that most households in Lake Tanganyika used bed nets to increase their fish catches. These fishing practices might increase fish catches in the short term but not be sustainable in the long term, putting the livelihoods and food security of the future generation at risk. For instance, a study by Pedroza-Gutiérrez and Lopez-Rocha [63] indicates that increasing fishing effort and changing gear type are the main causes of overfishing, and they led to a decline in the total fish production in Mexico.

The tilapia (Oreochromis), also known as the bream, is the most popular fish caught and traded by small-scale fishers in Lake Kariba. Maulu and Musuka [50] state that the tilapia fish population in Lake Kariba has declined, which forces small-scale fishers to target new species. The fishers pointed out that they are targeting new fish species for food and selling them to generate income. These perceived changes in fish species composition are supported by Karenge [60] who stated that the fish composition in Lake Kariba was changing, with S. zambezensis becoming the dominant species. Therefore, fishers are targeting the S. zambezensis for food and income. Musinguzi et al. [13] reported similar findings indicating that fishers in Lake Wamala observed a decline of the Nile tilapia and the increasing dominance of the African catfish, which created different fishing opportunities for fishers.

Smaller groups of fishers indicated the diversification of livelihoods and migration to new fishing grounds as some of the strategies adopted to cope with declining fish resources. Diversification of livelihoods by small-scale fishers has been reported in Lake Malawi [25] and Lake Wamala [13]. Brugere et al. [64] argue that diversifying to non-fishery activities could be the most beneficial adaptation strategy for fishers, as non-fishery activities can provide income during periods of low fish catches. However, in the areas under study, agriculture or livestock production is prohibited under Statutory Instrument 362 of 1990, which limits livelihood options for fishers of Lake Kariba [29]. Therefore, some adaptation strategies adopted by fishers to cope with declining fish resources are location specific.

The results of the factors influencing the adoption of specific adaptation strategies by fishers suggest that the fisher’s experience is the most significant and positive factor influencing the choice of adaptation strategies of fishers. Fisher’s experiences allow them to react and act against the effects of climate change on the fisheries sector. This finding is in agreement with the study by Sereenonchai and Arunrat [65] which found that fishers’ experience played a significant role in influencing their decision to adopt adaptation strategies in the Chumphon province of Thailand. In studying crop farmers, Tazeze et al. [66]; Oyekale et al. [67], and Nhemachena et al. [68] also found that farming experience influences the farmers’ decision to adapt to changing climatic conditions and the type of adaptation strategies adopted. Fishers’ education levels and perceptions about climate change significantly influenced their choice to adopt some adaptation strategies. Several studies have shown that the level of education correlates with the level of knowledge and the ability to make sound decisions [34]. Furthermore, the fishers’ perceptions influenced their choice of adaptation strategy because fishers have observed and experienced changes in fishery resources owing to climate change. This is supported by Nhemachena and Hassan [69], who state that farmers who noticed changes in climate had higher chances of adopting strategies to respond to the changes caused by climate change.

4.4. Limitations of the Study

The fishers’ perceptions of climate change, its effects on fisheries and adaptation strategies employed by fishers are specific to fishers in Lake Kariba and cannot be generalized to represent other small-scale fishers in Zimbabwe or the ZRB at large. Additionally, due to limited time, inadequate human and financial resources and limited access to some remote areas, data was collected from a small group of fishers based on their availability and willingness to participate in the study. Therefore, the sample is not an ultimate representation of all fishers in the area and data saturation might not have been achieved. The study assessed the socioeconomic factors that influenced the adoption of adaptation strategies employed by fishers but did not further investigate the influence and role of institutions in enhancing climate change adaptation in fishing communities found in the Zambezi River Basin in Zimbabwe.

5. Conclusions

The assessment of the fishers’ perceptions about climate change, its impacts on fisheries, and fishers adaptation strategies revealed that fishers have observed changes in temperature and rainfall trends over the last 10 years. Fishers have observed an increase in temperature and a decline in rainfall over the years. The frequency of extreme weather events, particularly drought, has increased. These observed changes has adversely affected the fisheries sector in multiple ways, including but not limited to fish habitat loss, declining fish stocks, reduced fish catches, reduced profits from fishery-related activities, food security, and increased threats to fishers’ lives. Fishers in Lake Kariba have adopted several strategies, such as changing fishing gear, increasing fishing time, increasing fishing effort, targeting new fish species, adopting alternative livelihoods, and migration in order to deal with changing fisheries resources due to climate change. However, some of the strategies adopted by fishers are detrimental and could enhance unsustainable fishing practices that can reduce the resilience of the ecosystem. Moreover, the fishers’ decisions to adopt certain adaptation strategies are mainly influenced by the fisher’s fishing experience, perceptions about climate change, and education level.

These local perspectives, when combined with scientific results for the study area, shed light on fishers social, economic, and environmental vulnerabilities, and can help inform local decision-making in terms of developing climate change adaptation measures. The study suggests the incorporation of fishers perceptions of climate change and the adaptation strategies used by them when formulating climate change adaptation policies for the fisheries sector. To understand how fishers perceive and adapt to climate change at a regional level, future researchers should conduct similar studies in fishing communities within the basin. Furthermore, there is a need to assess the local determinants of climate change adaptation and the role of institutions in enhancing the adaptation within fishing communities.