Vulnerability of freshwater fisheries and impacts of climate change in south Indian states economies

Abstract

We compare the vulnerability of 5 states in India national economies to potential climate change impacts on their capture fisheries using an indicator-based approach. States in India (e.g. Karnataka, Tamilnadu, Andhrapradesh, Kerala and Maharashtra) were identified as most vulnerable. This vulnerability was due to the combined effect of predicted warming, the relative importance of fisheries to national economies and diets, and limited societal capacity to adapt to potential impacts and opportunities. Many vulnerable states were also among the country's least developed states whose inhabitants are among the poorest and as twice as reliant on fish, which provides 32% of dietary protein compared to 12% in less vulnerable states. These states also produce 25% of the country's fish exports and are in greatest need of adaptation planning to maintain or enhance the contribution that fisheries can make to poverty reduction. Reducing fish mortality in the majority of fisheries, which are currently fully exploited or overexploited, is the principal feasible means of reducing the impacts of climate change. Dharwad in 2003. He received the prestigious IISc centenary post doctoral fellowship from IISc. He is presently working as a scientist in Indian Institute of Science, in centre for sustainable technologies department, Bangalore and has many research papers published and presented at national and international level. His research areas of interests are ecotoxicology, aquatic biodiversity, natural resources monitoring, assessment of coastal ecosystem and marine biodiversity. He is a member of FSBI (UK), National Geographic (Hong Kong), BES (UK), NALMS (USA). He is also a member of the Society for Experimental Biology (UK) and Biochemical Society (UK).

Full text

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Author version: Interdis. Environ. Rev., vol.12(4); 2011; 283-297
Vulnerability of freshwater fisheries and impacts of climate change in south
Indian states economies
D. Sannadurgappa
Centre for Sustainable Technologies, Indian Institute of Science, Bangalore 560012, India.
E-mail:durgappa@astra.iisc.ernet.in
Tel-91-080-22933346

R. Abitha
Centre for Sustainable Technologies, Indian Institute of Science, Bangalore 560012, India.

Soniya Sukumaran
Regional Centre, National Institute of Oceanography, Mumbai 400 053, India
Abstract: We compare the vulnerability of 5 states in India national economies to potential climate
change impacts on their capture fisheries using an indicator-based approach. States in India (e.g.
Karnataka, Tamilnadu, Andhrapradesh, Kerala and Maharashtra) were identified as most vulnerable.
This vulnerability was due to the combined effect of predicted warming, the relative importance of
fisheries to national economies and diets, and limited societal capacity to adapt to potential impacts and
opportunities. Many vulnerable states were also among the country’s least developed states whose
inhabitants are among the poorest and as twice as reliant on fish, which provides 32% of dietary protein
compared to 12% in less vulnerable states. These states also produce 25% of the country’s fish exports
and are in greatest need of adaptation planning to maintain or enhance the contribution that fisheries can
make to poverty reduction. Reducing fish mortality in the majority of fisheries, which are currently
fully exploited or overexploited, is the principal feasible means of reducing the impacts of climate
change.
Key words: climate change, fisheries, vulnerability, poverty

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Reference to this paper should be made as follows: Sanndurgappa, D. (2010) “Impacts of climate
change on fisheries and vulnerability of southern Indian state economies”, Interdisciplinary
Environmental review.
Biographical notes: D. Sannadurgappa received his PhD in Zoology from Karnataka University
Dharwad in 2003. He received the prestigious IISc centenary post doctoral fellowship from IISc. He is
presently working as a scientist in Indian Institute of Science, in centre for sustainable technologies
department, Bangalore and has many research papers published and presented at national and
international level. His research areas of interests are ecotoxicology, aquatic biodiversity, natural
resources monitoring, assessment of coastal ecosystem and marine biodiversity. He is a member of FSBI
(UK), National Geographic (Hong Kong), BES (UK), NALMS (USA). He is also a member of the
Society for Experimental Biology (UK) and Biochemical Society (UK).
Biographical notes: R. Abitha completed her Bachelor of Engineering in Environmental Engineering
and is currently working as a research scholar (Ph.D) in Indian Institute of Science in the centre for
sustainable technologies department.
Biographical notes: Dr. Soniya Sukumaran working as Scientist in Regional Centre in National
Institute of Oceanography, Mumbai 400 053, India

1 Introduction
The North Sea ecosystem provides 5 per cent of the global fish harvest and has been fished heavily with
a particular effect on cod (Gadus morhua L.) (Hulme et al., 2002). It is previously shown that
temperature is more important than wind intensity and direction, salinity, nutrients and oxygen in
determining the North Atlantic and North Sea ecosystem dynamic regime (Smit and Wandel, 2006).
During the 1980s, the North Sea experienced a change in hydro-climatic forcing that caused a rapid,
temperature-driven ecosystem shift (Newton et al., 2007). Because of the unrealized response of the
climate system to historical greenhouse gas emissions, the planet is committed to at least as much
warming over the 21st century as it has experienced over the 20th century (≈0.75°C) regardless of
possible future actions to reduce emissions. Failure to slow the increase in atmospheric greenhouse gas
concentrations only increases the warming. Adaptation to the anticipated warming is essential.

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As the planet's climate changes so too will populations, species and ecosystems, with profound
consequences for fisheries change (Smit and Wandel, 2006). Where will climate change impacts on
fisheries have greatest social and economic significance? This is a simple question, but a comprehensive
answer would require predictions of the geographic patterns of global warming (from global circulation
models) and predicted impacts of atmospheric warming on climatic, hydrological and oceanographic
processes (from physical models). These changes in physical processes would then need to be linked to
ecological processes using coupled physical-ecosystem models – if they were available (Brander, 2007).
Yet informed predictions at these scales are urgently needed, because most policy responses relating to
planned climate change adaptation and fisheries management are or will be implemented at national
levels and even those at local levels will be derived from decisions made at national levels. Until the
development of detailed global-scale 'physics-to-fish-to-fishers' models, one pragmatic approach is to
use indicators in combination with a risk-assessment or vulnerability framework (Newton et al., 2007).
Ecosystems exist as dynamic regimes controlled by the interplay among species, the
environment and how they interact with external forces such as climate. Many studies have reported the
rapid alteration of marine ecosystems throughout the world (Jennings and Blanchard, 2004). Although
human activities and especially fishing are often held responsible for these abrupt ecosystem shifts, the
oceanic biosphere is now also experiencing rapid global climatic change. But all of this takes us only
half way to an answer; predicting the impacts on people would further require an understanding of the
social and economic dynamics of fishing fleets and fishing communities, and their capacity to adapt to
change. Such integrated predictions of the impact of climate change are beyond the current frontiers of
our knowledge, particularly at national or smaller scales. In the meantime, fishers are already being
affected by changes that are ultimately driven by rising global atmospheric temperatures. For example,
coastal fishers in Bangladesh face increased frequency and severity of hurricanes, coupled with the
greater penetration of saline water into coastal land due to thermal expansion of the warming oceans
(Unnikrishnan et al., 2006) the people of the Chad basin converge around their shrinking lake, as
regional warming drives decreased rainfall and increased evapotranspiration and the coastal fishers cope
with bleached coral reefs as atmospheric warming leads, in turn, to warmer seas and higher bleaching
susceptibility. Set within a context of overexploitation of many of the world's fisheries (Mullon et al.,
2005; Newton et al., 2007), policy makers urgently require information and analysis to guide
investments and initiatives in climate change mitigation and adaptation.

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Additionally, little attention has been given to the consequences of changing fisheries
ecosystems on people, particularly so for the millions of small-scale fisher folk (fishers, fish processors,
traders and ancillary workers) in the developing world who are among the most vulnerable to climate
change (McClanahan et al., 2008). While there is a growing body of case studies on the observed effects
of climate change on the distribution and production of individual fisheries (Brander, 2007), it is
difficult to estimate or predict the broader or aggregate effects of climate change at national and regional
scales (Brander, 2007). To date, global and regional climate vulnerability assessments have focused on
agricultural production; fisheries have not yet been systematically evaluated (Tubiello et al., 2007).
Vulnerability is typically defined as a combination of the extrinsic exposure of groups or
individuals or ecological systems to a hazard, such as climate change, their intrinsic sensitivity to the
hazard, and their lack of capacity to modify exposure to, absorb, and recover from losses stemming from
the hazard, and to exploit new opportunities that arise in the process of adaptation ( Smit and Wandel,
2006). This analysis is the first systematic attempt to compare the relative vulnerabilities of national
economies to potential climate change impacts on fisheries at a global-scale. In this paper, we provide an
indicator-based analysis of the relative vulnerabilities of 5 states to climate change impacts on fisheries.
We use a vulnerability assessment framework developed to identify states highly exposed to
hazards related to climate change, where livelihoods and economic growth depend on climate-sensitive
industries, such as agriculture, fisheries, forestry and tourism, and where limited resources,
infrastructure and societal capacity constrain adaptation (Smit and Wandel, 2006). The increase in
carbon dioxide emissions has resulted in an increase in CO2 concentrations in the oceans (IPCC, 2007),
reducing oceanic pH and changing the saturation horizons of aragonite, calcite, and other minerals
essential to calcifying organisms (Newton et al., 2007).
2 Study Area
The study areas selected are 1) Aghanashini river in Karnataka. 2) Lakshmipuram reservoir of
Vishakapatanam district in Andhrapradesh. 3) Kempanayakana palya of Coimbatore district in
Tamilnadu. 4) Periyar river in Kerela and 5) Tansa river in Thane, Maharashtra shown in Figure 1.

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Figure 1
India map showing study area of five states i.e. Karnataka, Tamilnadu, Kerala,
Maharashtra and Andhrapradesh.

3 Methods
3.1 Climate vulnerability assessment
While this analysis may have greatest relevance to the national policies in India that facilitate climate
adaptation processes and management of fisheries systems, our approach complements local site-
specific assessments looking at individual and fisher folks' community adaptation, as well as case
studies investigating the impact of climate change on particular states. We focus on the vulnerability of
state economies to potential impacts of a single large-scale driver, climate change. While additional
drivers such as fishing pressure, fuel prices, future changes in trade flows and consumption patterns are
important in shaping fisheries production systems. We choose to focus on a state scale, mainly because
appropriate policies are generally formulated and implemented at this scale, but also because many
global indicators are available only at states and national scale. State-level assessments provide a broad
view of vulnerability patterns and may be used to identify particularly vulnerable regions and eventually
facilitate comparison of vulnerability assessments across natural resource-dependent industries,
potentially providing insight into processes that cause and exacerbate vulnerability (Yohe et al., 2006).

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3.2 The three components of vulnerability
Vulnerability to climate change depends upon three key elements: exposure (E) to physical effects of
climate change, the degree of intrinsic sensitivity of the natural resource system or dependence of the
national economy upon social and economic returns from that sector (S), and the extent to which
adaptive capacity (AC) enables these potential impacts to be offset (IPCC, 2001a). There are no
objective, independently derived measures of exposure, sensitivity, or adaptive capacity, and so their
relevance and interpretation depend on the scale of analysis, the particular sector under consideration
and data availability (Sullivan and Meigh 2007).
We chose measures of exposure, sensitivity and adaptive capacity that likely to best capture the
properties of interest, based on previous vulnerability studies (O'Brien et al., 2005). The choice of
variables is similar to that of other constructed indices such as the Disaster Risk Index, Water Poverty
Index and the Hotspots program (Sullivan and Meigh, 2007), and was driven by a consideration of a
number of factors including: the number of states for which data were available, the availability of
recent data, and the degree of direct relevance to the phenomena that the indicators are intended to
represent. As this is the first study that specifically addresses the sensitivity of the fishery sector, we
identified indicators of economic dependence on fisheries based on a review of the scientific literature
(Adger et al., 2005). For the three key elements of vulnerability (i.e. Exposure, Sensitivity, and Adaptive
Capacity) the derivation of each indicator is detailed below.
3.3 Effects of fishing

Fisheries might interact with climate change in causing changes in fish populations, through various
mechanisms. Climate change could affect the distribution of particular species and hence their
susceptibility to particular fishing fleets, becoming more or less "catchable" as a result. Similarly,
climate-related distribution shifts may affect the protective capabilities of closed-areas, because species
or life stages may shift outside the boundaries of the protected area and hence become vulnerable to
fishing (O’Brien et al., 2000).
Extensive fishing may cause fish populations to become more vulnerable to short-term natural
climate variability (O’Brien et al., 2000), by making such populations less able to "buffer" against

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the effects of the occasional poor year classes. A major implication is that fishery-induced
impoverishment of stock structure (reduced and fewer ages and smaller sizes) can increase the sensitivity
of a previously "robust" stock to climate change Conversely, long-term climate change may make
stocks more vulnerable to fishing, by reducing the overall carrying capacity of the stock, such that it
might not be sustained at, or expected to recover to, levels observed in the past (Bakun, 1990).
Fishing will have a major influence on the size structure and species composition of fish
assemblages and thus will affect predator–prey relationships (Barange, 2002). Fishing will interact with
global warming, because body size generally increases with latitude (CWP, 2004) and small fish species
may take advantage of the removal of the larger predatory fish (Edwards et al., 2002). Fishing may
also affect ecosystem control causing bottom-up systems to become top-down controlled systems (see
the section "Ecosystem response"). How climate change will interact with fishing will depend on the
species affected and eventually on the prevailing patterns of ecosystem structure and function
(Handisyde et al., 2006). Hence, the response of ecosystems under climate and fishing pressure
is currently difficult to predict.
3.3.1 Sensitivity
Table 1 Relative vulnerabilities of state economies and climate change-driven impacts on fisheries.
Rank State Vulnerability E S AC

1 Kerala 0.74
0.72
(36)
0.66
(54)
0.60
(32)
0.67
(22)
0.64
(24)

0.59(47)

0.45(42)
0.94 (2)
2 Karnataka 0.72 0.91 (5)
3 Andhrapradesh 0.71 1.00 (2)
0.73
(28)
0.75
(25)
0.55 (76)
4
5
Maharashtra
Tamilnadu
0.71
0.70
0.84 (12)
0.56(45)

Index values (rankings) of exposure (E), sensitivity (S) and adaptive capacity (AC). All rankings are
relative to the entire dataset (n = 5 states).

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Two metrics of the contribution we used for fisheries to national employment: total number of
fishers and the number of fishers expressed as a proportion of the economically active population (EAP).
These two variables are only weakly correlated (Spearman's ρ = 0.40) and they capture and represent
different elements of sensitivity, because strong dependence on fisheries for employment may reflect
either high absolute dependence (i.e. a large number of fishers) or relative dependence (i.e. a large
proportion of the national workforce), or in some cases, both. Estimates of fisher numbers were derived
from the most recent national census data; we caution that these values probably underestimate true
numbers because of the recognized difficulties in enumerating fishers (CWP, 2004). Sensitivity is
usually defined as the intrinsic degree to which biophysical, social and economic conditions are likely to
be influenced by extrinsic stresses or hazards (IPCC, 2001a). However, because climate change may
influence ecological and human aspects of fisheries in complex ways, we considered sensitivity in a
slightly different context. Instead we assume that the sensitivity, in this context, is represented by the
fisheries dependence which we consider to be the importance of fisheries to national economies and
food security. The nutritional dependence of the human population on fisheries was represented by the
total fish available for consumption per country expressed as a proportion of all consumed animal
protein. Fish consumption was estimated as annual total supply (production + imports - exports - non-
food uses) from FAO food balance sheets, and expressed as grams of product consumed per person per
day (FAOSTAT, 2004).
3.3.2 Adaptive capacity
Elements of adaptive capacity comprise such as levels of social capital, human capital and the
appropriateness and effectiveness of governance structures (Vincent, 2007). The adaptive capacity index
in this study was a composite of four human development indices (healthy life expectancy, education,
governance and size of economy). These variables were chosen on the assumption that states with high
levels of economic and human development have the resources and institutions necessary to undertake
planned adaptation. CAIT is an information and analysis tool on global climate change, providing a
publicly available database of comparable climate-relevant indicators, which are drawn from reputable
international and national sources. The Climate Analysis Indicator Tool (CAIT) developed by the World
Resources Institute was used to combine these four variables (CAIT, 2005).

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3.3.3 Economic impacts
A key factor concerning future economic impacts is the need to identify which countries and regions are
most vulnerable. Modeling studies have assessed country vulnerability on the basis of exposure of its
fisheries to climate change, high dependence on fisheries production, and low capacity to respond. The
studies show that climate will have the greatest economic impact on the fisheries sectors of central and
northern states of India. Indirect economic impacts will depend on the extent to which local economies
are able to adapt to new conditions in terms of labour and capital mobility. Change in natural fisheries
production is often compounded by decreased harvest capacity and reduced access to markets. Country’s
fish production is forecast to increase more slowly than demand to 2025, and the proportion of
production coming from aquaculture is forecast to increase. Therefore, zero growth in capture fisheries
production will not threaten total supply unduly, but a decline could affect countries fish consumption
(Hulme et al., 2002).
4 Results
4.1 Present fisheries production, trends, and threats in southern India
4.1.1 Production and trends
Sixty one percent of the 78 million tons total country’s aquatic production in 2006 was from marine
systems, and the remaining 22% was from inland waters. Aquaculture production is rising rapidly, and
by 2030 it is estimated that aquaculture production will be close to that of capture production in southern
India (Newton et al., 2007). Human impacts on fisheries production and consumption represented in
ratio, consumption increased in faster rate than production and 30% of livelihood is affected and 10% of
fish species reduced. These trends are shown in the Figure 2.
4.1.2 Threats
The principal threats to future fisheries production identified here are expected to act progressively (i.e.,
a linear response) and to interact with each other. However, marine ecosystems can also respond to
changes in physical or biological forcing in a nonlinear way (Hulme et al., 2002,), e.g., when a threshold
value is exceeded and a major change in species composition, production, and dynamics takes place. We
know that such nonlinear responses occur but do not yet understand how or under what conditions. This
is a key limitation in our ability to forecast future states of marine ecosystems.

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Figure 2
Trends of fisheries in southern India (a) Human impact on Fish Resources, (b) Impacts
on Livelihood, (c) Disappeared Species




4.2 Fishing activity
Fishing is the greatest threat to future fish production; however, the impacts of fishing and of climate
change interact in a number of ways, and they cannot be treated as separate issues. Fishing causes

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changes in the distribution, demography, and stock structure of individual species and direct or indirect
changes in fish communities and marine ecosystems. These changes have consequences for other
ecosystem services (such as nutrient cycling and recreational use) and for sustainability, resilience and
ability to adapt to climate change, and other pressures. Figure 3 shows the relationship between the
impacts of climate change and fishing activity on the marine ecosystem and its fish component. Future
sustainable fisheries depend on effective management of fishing activity, which in turn requires an
understanding of the effects of climate change on the productivity and distribution of exploited stocks.
Management must take into account the interactive effects of fishing, climate, and other pressures.
Fishing is size-selective and causes changes in the size and age structure of populations, which
results in greater variability in annual recruitment in exploited populations. The truncation of age
structure and loss of geographic substructure within populations makes them more sensitive to climate
fluctuations (Newton et al., 2007). To sustain the resilience of fish populations, in particular when they
are confronted by additional pressures such as climate change, their age and geographic structure must
be preserved rather than relying only on management of their biomass. We are currently fishing most
stocks at levels that expose them to a high risk of collapse, given the trends in climate and the
uncertainty over impacts.
Figure 3 schematic representations of impacts of climate change and fishing activity on the marine
ecosystem and its fish component.

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Fishing is one of a number of human pressures that have resulted in a global decline in biodiversity. This
raises concerns over the role biodiversity plays in maintaining ecosystem services and, in particular,
resilience to climate change. A recent meta analysis concluded that the oceans' capacity to provide food,
maintain water quality, and recover from perturbation has been impaired through loss of biodiversity
(Vincent, 2007), but other studies of the relationship between biodiversity and ecosystem functioning
and services produce a more nuanced picture.
4.3 Direct and indirect effects of climate change on distribution, productivity, and extinction.
In India climate change has both direct and indirect impacts on fish stocks that are exploited
commercially. Direct effects act on physiology and behaviour and alter growth, development,
reproductive capacity, mortality, and distribution. Indirect effects alter the productivity, structure, and
composition of the ecosystems on which fish depend for food and shelter.
The effects of increasing temperature on marine and freshwater ecosystems are already evident,
with rapid pole ward shifts in distributions of fish and plankton in regions, where temperature change
has been rapid (Sullivan and Meigh 2007). Further changes in distribution and productivity are expected
due to continuing warming and freshening. Some of the changes are expected to have positive
consequences for fish production (Vincent, 2007), but in other cases reproductive capacity is reduced
and stocks become vulnerable to levels of fishing that had previously been sustainable. Local extinctions
are occurring at the edges of current ranges, particularly in freshwater and diadromous species (Adger ,
2000).
4.4 Exposure to climate change
Warming will be moderate in southern parts of India. Relatively smaller temperature increases are
predicted for nations in northern part. Predicted temperature increases for the final 5 states in the dataset
were very highly correlated between the two scenarios.

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4.5 Sensitivity or dependence of national economies upon the fisheries sector and adaptive capacity
and vulnerability

The largest fisheries in terms of total capture production and employment were in the Kerala and
Tamilnadu. As expected, the largest reported landings were associated with those states traditionally
considered the countries major fishing nations (FAO, 2007). The lowest levels of production were
mainly associated with landlocked states (e.g. Karnataka). The states with the lowest adaptive capacity
were concentrated almost exclusively Tamilnadu, and Kerala. Virtually all south Indian states, except
Karnataka, had low adaptive capacity. The only highly vulnerable states in the higher latitudes were
Tamilnadu, Andhrapradesh and Kerala, reflecting their relatively important fishing fleets, high level of
exposure to predicted climate change and relatively low adaptive capacity. The region’s most vulnerable
to climate-induced changes in fisheries were particularly Tamilnadu, Andhrapradesh and Kerala.

5 Discussion
The high vulnerability in Indian states reflects different combinations of climate exposure, sensitivity or
fisheries dependence and adaptive capacity (Table 1). Understanding how these various factors combine
to influence vulnerability provides a useful starting point for directing future research and climate
change adaptation and mitigation initiatives. This study is the first to identify states whose economies
are potentially the most vulnerable to future climate change impacts on the fisheries sector. Although
warming will be most pronounced at high latitudes, the states with economies most vulnerable to
warming-related effects on fisheries lie in the tropics.
South Indian states fisheries are important to the poor, and regional assessments indicate that
fishery production in both continental and marine waters is closely tied to climatic variation. West Coast
states have large coastal populations that rely upon exploitation of rich marine upwelling fisheries,
landings from which are largely driven by irregular low frequency oscillation in oceanic and
atmospheric climate conditions (Dulvy et al., 2009). Fish are an important protein source for some of
these West coast states, comprising nearly two-thirds of daily animal protein intake (FAO, 2004). Many
of these fisheries are already subject to overfishing by both local, Indian fishing fleets with access
agreements (Mitchell et al., 2004). In Eastern fisheries, landings are derived largely from freshwaters
(FAO, 2004). In the deeper Rift Valley lakes, such as Lake Tanganyika, climate change has been

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associated with increases in surface water temperature, reduced primary productivity and reduced fish
catch rate over the last century (Metzger et al., 2005). Water levels and surface areas of some large
shallow African lakes (Lakes Chilwa, Bangweulu and Chad) fluctuate with regional rainfall anomalies
(Reid et al., 2007), these climatic and hydrological fluctuations are mirrored by changes in fishing
activity and catches. Vulnerable Asian countries face combinations of three issues: high fisheries
dependence, heavily-exploited marine ecosystems, and high exposure of major riverine and coastal
fisheries to climate change.
Fish constitute a high proportion of export income in parts of South and Southeast Asia, and a
major source of dietary protein – typically 40% of all animal protein consumed per year. The
consequences for the region's highly productive river and floodplain fisheries – a vital component of the
rural economy - are uncertain and depend on the interaction between local rainfall and glacier melt
profiles, the importance of dry vs. wet season water levels for fish productivity, and increasing irrigation
demands for domestic, agricultural and industrial use (Vorosmarty et al., 2000; Alcamo et al., 2003).
Fisheries production of some of the more vulnerable countries in Asia relies on rivers that arise in the
Himalayan Mountains - the Indus, Brahmaputra, Ganga and Mekong. Climate change is likely to cause
earlier season peak flows and possible reductions in flow, attributable to reduced snowfall and melting
glaciers (Barnett et al., 2005). For example, predicted summer flows in the Ganges will be reduced by
two-thirds (WWF, 2005). Southeast Asian coral reef fisheries already appropriate four times their
sustainable catch and their reefs are heavily at risk from coral bleaching induced by climate change
(Bryant et al., 1998; Warren-Rhodes et al., 2003; Newton et al., 2007). Climate shocks on these Asian
fisheries are predicted to have significant economic consequences for the poorest consumers (Briones
et al., 2005).

to a change in temperature (and other climate-driven changes in abiotic factors). It will allow us to define
Knowledge of the eco-physiology will provide a strong basis to infer the response of a species
the bioclimateenvelope and evaluate the change in habitat suitability (Perry et al., 2007), or
evaluate whether observed temperature changes may be responsible for the change in the population
abundance, such as for the eelpout in the Wadden Sea (Pauly et al., 1987). Although we have mainly
dealt with temperature, climate change may also affect oxygen, salinity, and ocean pH. These factors
may load the metabolic scope and decrease the tolerance range of the organism (Sims et al., 2001),
subsequently making it more vulnerable to climate change.

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6 Conclusions

While the detailed effects of climate change and direction of change on the physical and biological
processes that affect individual fisheries are uncertain. An important element of climate change that
could represent 'dangerous anthropogenic interference' (UNFCCC, 2006) is the vulnerability of the
economies of some of the countries fishing states to climate change impacts which could affect their
food security and levels of poverty by elevating stress on fisheries production. In addition to the effects
of climate change, fisheries production systems are already under considerable stress from overfishing,
habitat loss, pollution, invasive species, water abstraction and damming. Overall the large-scale climate-
related changes in fisheries are likely to bring either increased economic hardship or missed
opportunities for countries that depend upon them but lack capacity to adapt. Fortunately most climate
change adaptation measures thus go hand-in-hand with attempts to reduce both poverty and overfishing
through strengthening livelihoods, economies and environmental governance.

Building adaptive capacity is a necessary response, both for countries where climate change may
bring improved fishing opportunities and for those where detrimental impacts are foreseen. Countries
with weak economies and poor governance are less able to translate improved fishery productivity into
reduced poverty. In the absence of enhanced capacity to cope with and adapt to the impacts of climate
change, the disruption of fisheries by climate change is likely to affect large numbers of poor people,
and reduce the options for future economic growth in those states for which fisheries are important
sources of food, employment and export revenues. South Indian states that are most vulnerable to
climate change impacts on their fisheries are also the poorest: The inhabitants of vulnerable states are
twice as dependent upon fish for food as those of other states, with 32% of dietary protein derived from
fish compared with 12% elsewhere. Yet a considerable proportion of fish captured by the most
vulnerable states is exported. The most vulnerable states produce 25% of counties fishery exports.


response of affected fish population too is multifaceted, we believe that scientific progress will benefit
from an approach where a priori hypotheses are formulated based on first principles of the relevant
levels of organization. The hypotheses proposed here are by no means complete. They should rather be
regarded as a first set of hypotheses. These hypotheses seek to compare species and species-groups that
Given the complexity of the problem, where climate change is a multifaceted driver and the