A Climate for Change

Human Development Report - Croatia 2008 The Fishing and Mariculture Industries^159

Groupers and bluefish are two examples where the ef-
fects on fish populations and the industry were mixed
or negative.

GroupersXXIII were rare fish in the Southern Adriatic
and non-existent in the Middle and Northern Adriatic
before the 1990s. In the 1990s, they began to migrate
and, in the last 10 years several additional grouper
species have been identified for the first time in the
Middle/ Northern Adriatic.^26 The overall impact on
commercial fishing has been positive: they are lucra-
tive, marketable fish. However, from a biological and
ecological standpoint, there have been negative ef-
fects: the abundance of some native speciesXXIV is now
significantly lower due to competition with groupers.^27

While the introduction of groupers had a positive eco-
nomic impact, the introduction of bluefish did not.
BluefishXXV were first recorded in the Northern Adri-
atic in 2004.^28 The fish is a typical predator, preying
mainly on grey mullets. It appeared several years ago
in the Neretva River estuary, where grey mullet fish-
eries are the most important segment of the fishing
industry, and decimated the grey mullet population in
only a few years. They also destroyed the nets particu-
larly adapted for the traditional grey mullet industry.
As the local fishermen have not developed the nec-
essary tools to catch the bluefish, the traditional grey
mullet fishery is close to collapse, while the economic
benefits that might have been gained by catching
bluefish have not materialised. In fact, most sugges-
tions for addressing the crisis focus on eradicating the
bluefish.^29

Two potentially poisonous fish species have also been
recorded in the Adriatic Sea^30 – the oceanic puffer fish
and the blunthead puffer fish.XXVI These fish have tox-
ins (tetrodoxin) in their body and if not prepared prop-
erly their consumption can lead to death, as observed
in Lebanon and Egypt. Although still rare fish in the
Adriatic, their presence should become the subject
of a public education campaign – especially amongst
subsistence fishermen – to raise awareness about the
potential danger of these fish to the public.

9.6. Potential socio-economic

impacts of climate change on

fisheries and mariculture

More research is necessary before determining the

likely net effect of climate change on the fishing sec-

tor, particularly because increased sea temperatures

affect species differently. However, certain relation-

ships are already emerging.

9.6.1. Changes in revenue

First, changes in the distribution of species in the Adri-

atic will result in changes in revenue for the fishery

sector, and benefits and losses may not be distributed

equally. Invasive species provide an illustrative exam-

ple. The destruction of the grey mullet population in

the Neretva River estuary by bluefish represented an

acute economic loss for the fishermen. On the other

hand, reductions in the populations of some coastal

fish due to the arrival of groupers were offset by the

ability to catch and sell this newer invasive species,

which resulted in a net economic benefit. However,

due to the illegal marketing of these lucrative species,

in both cases it is hard to estimate the present revenue

loss or benefit. This example also indicates the impor-

tance of adaptive capacity. In the case of the groupers,

the fishing sector was able to adapt to the arrival of

the new species by catching it and selling it. In the

case of the bluefish, the inability to capitalize on its

presence commercially meant that losses in the grey

mullet population were not offset by new revenue.

XIII fam. Serranidae

XIV These species are mainly sparids, such as white sea bream Di-

plodus sargus

XV Pomatomus saltatrix

XVI Lagocephalus lagocephalus lagocephalus and Sphoeroides pachy-

gaster.