Impacts and Adaptations to Climate Variability and Change in Inland Fisheries and Riparian Ecosystems 1 Ogutu-Ohwayo R., K.N. Odongkara 1 , W. Okello 1 , S.B. Wandera 1 , J. Efitre 2 , M. Bwambale1, V. Natugonza 1 1 National Fisheries Resources Research Institute, Jinja, Uganda 2 Departments of Biological Sciences, College of Natural Sciences, Makerere University, Kampala, Uganda
Outline of the Presentation I. General Aspects of Climate Change; II. Vulnerability and Impacts of Inland Aquatic Systems and Fisheries; III. Adaptation and Coping Strategies by Fishers and Riparian Communities; IV. Conclusions and Recommendations for Action; and V. Mainstreaming Climate Change in Fisheries.
I. General Aspects of Climate Change
1. Definition and Parameters of Climate Change Climate is the average weather of a given region averaged over a long period (at least 30 years) & includes weather parameters such as: Temperature; Droughts and dryness; Atmospheric pressure; Humidity; Wind speed; Precipitation (rainfall); Sunshine; and Cloud cover Climate variability and change involves a shift in these parameters due to natural or human factors
2. Manifestations of Climate Change Climate change is manifested in the form of: Rising temperatures; Increased evaporation; Fluctuation in precipitation (rainfall); Floods and wetness; Droughts, desiccation and dryness; Intense winds, storms and hurricanes; and Re-configuration of ecosystems & organisms including changes in their productivity and biological characteristics.
3. Socio-economic Impacts Displacement of communities; Damage to infrastructure; Water and food shortages; Poor sanitation; Increasing incidences of diseases e.g. cholera, & bilharzias; and Changes in resource availability.
4. Causes of Climate Change Climate change is caused by global warming due to accumulation of green house gases (GHG) mainly CO 2 in the atmosphere from burning of fossil fuels. It is exacerbated by deforestation which reduces the capacity to absorb GHGs. The GHGs have accumulated for over 100 years & even if emissions were eliminated it would not immediately stop global warming. Hence the need for development of adaptation strategies.
5. Vulnerability The poor are most vulnerable to climate variability and change and there is need to safeguard them. About 30% of Ugandans live below the poverty line and 70% depend on crops, livestock and fisheries which are sensitive to climate variability and change. A large proportion of Ugandans are therefore vulnerable and there is need to understand the impacts of climate change on these sectors and to equip, especially the poor, with knowledge and practices to adapt and become more resilient.
6. Importance of Aquatic Resources The East African Great lakes region is rich in inland aquatic resources Uganda has 5 large lakes, 160+ small lakes, rivers & wetlands covering about 21% of the national surface area. These aquatic systems, most of which are shared with her neighbors, cover about 80,000 km 2 , hold 3,000 km 3 of freshwater, & produce about 1.5 million tons of fish annually They are important sources of: Food, income & export earnings; Biodiversity; Water for domestic, agriculture & industrial use; Hydropower; Navigation & Modulation of local climate.
7. Addressing Impact of Climate Change Addressing climate change in Uganda and elsewhere has concentrated on crops, livestock & forestry & less on fisheries despite the high economic importance of fisheries to the national economies and vulnerability of fish production systems to climate variability and change. There is no adaptation plan of action for fisheries in the Ugandan National Adaptation Plan of Action (NAPA) to climate change. NARO and NaFIRRI recognize climate change as a major problem but fisheries research has not previously had it among its core research areas. Local, regional and international examples show that climate change affects riparian & aquatic ecosystems fisheries, & livelihoods, & should be mainstreamed into fisheries & NAPA.
8. How Climate Change Operates The heat increases the Greenhouse gases Earth’s temperature trap heat Result in socio-economic Increased temperatures affect consequences physical, chemical & biological processes
9a. Evidence of Climate Change The Intergovernmental Panel on Climate Change (IPCC) has reported that the last two decades of the 20 th century were the warmest; The average global temperature increased by 0.7 o C since mid-20 th century & that over Africa by about 0.5 o C; The surface temperature of aquatic systems increased; and Fluctuations in intensity of storms, floods, droughts, hurricanes, precipitation & frequency of droughts has increased.
9b. Frequency of Droughts in Uganda The frequency of drought in Uganda increased since 1970s (NAPA, 2007) which coincides with the period of the highest global warming reported by IPCC showing that Uganda is being impacted by climate change.
II. Vulnerability and Impacts of Inland Aquatic Systems and Fisheries
10a. Vulnerability of Fish Production Systems Fish production systems are highly vulnerable to climate variability and change. Lakes in Eastern Africa have experienced fluctuation in water levels, desiccated and even dried due to climate variability and change. (Nichoson & Xungang, 2001)
10b. Lake Chad Shrunk to 10% its size within 15 years between 1972 (left) and 1987 (right) [Dropped 22,903 to 304 km 2 :1963 & 2001]
10c. Changes in water levels of Ugandan Lakes Edward and George had low water levels over the past 5000 years, Albert was reduced, Victoria was dessicated as recently as 12,000 years BP and the water levels of these lakes have fluctuated in recent times as demonstrated by lakes Victoria 1870 - 2000 (top) and Kyoga1948 - 2003, (bottom) water levels. Although these changes are due to natural cycles, they show that aquatic systems are vulnerable to human induced changes in climate.
10d. Trends in Annual Precipitation near Lake Wamala 1950-2004 Annual precipitation around Lake Wamala varied due to natural causes but has become more erratic since the about 1975 when climate change became more intense
10d. Fluctuations in Area of Lake Wamala The lake covered ~250 km 2 in 1980s, shrank to about half in early 1990s, recovered from late 1990s into late 2008 but the water gauges were still above water level by 2011 suggesting that it had not fully March 1995 July 1984 recovered Dec. 1999 Feb. 2008 May 2011
11. Components of Aquatic Ecosystems Impacted Riparian ecosystems & infrastructure; Aquatic habitats; Aquatic productivity processes (nutrients, phytoplankton & Invertebrates); Life history of fishes; Fisheries production; and Livelihoods of fishery dependent communities
12a. Effects on Riparian Ecosystems and Infrastructure Flooding; Desiccation and shrinkage; Infrastructure damage; Displacement of communities; Effect on ecosystem integrity and biodiversity including wetlands.
12b. Impact of Floods on Lake Kyoga El-Ni ń o rains of 1997/98 dislodged water hyacinth & papyrus Cyperus papyrus which blocked the outlet, raised the water level by 1.5 m, increased the volume of the lake from an average of 7.7 km 3 in 1997 to 13.6 km 3 in 2003, flooded 580 km 2 of land, displaced human populations, destroyed infrastructure and caused economic losses
13. Effects on Aquatic Habitats Fluctuations in water levels in both shallow and deep lakes; Shrinkage and even desiccation and as in Chad, Chilwa and Wamala; and Affects water circulation, causes stratification and enhances anoxia (oxygen deficiency) in deep lakes
14a. Effects on Aquatic Productivity Processes Changes in nutrient circulation; Changes in phytoplankton primary production & composition; Changes in invertebrate production & composition; Alteration in food-webs; and Shifts in fish communities and fisheries.
14b. Changes in Phytoplankton Production in Lake Tanganyika Warming of surface waters of Lake Tanganyika by about 2 o C is estimated to have decreased algal productivity by 20% and fisheries yield by 30% (O’Reilly et al., 2003)
15a. Impacts on Life History of Fishes Physiology of fishes which are cold blooded; Composition and diversity; Distribution; Relative abundance; Population structure; Recruitment rates; Biological characteristics of fishes (food and feeding habits, size at maturity, sex ratios, condition factor etc.).
15b. Changes in Water Level, Life-history Parameters and Fishing Practices for Nile Tilapia on Lake Wamala Parameter Water depth (m) 1.5 4.0 Max. Size (cm) 20 40 Size at maturity (cm) 15 25 Mesh size of net used to fish (mm) 51 102 Fluctuations in depth of Lake Wamala between 1.5 and 4 m was accompanied by fluctuations in max. size of Nile tilapia between 20 and 40 cm, the size at first maturity between 15 and 25 cm, and shifts in the gillnet mesh size used for fishing between 51 and 102 mm.
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