Download Taking stock: Alien species in Maltese waters

THE
LUMINARY
UNIVERSIT Y OF MALTA ALUMNI NEWSLET TER
www.um.edu.mt/alumni
AUGUST 2015
Taking stock:
Alien species
in Maltese
waters
The Department of Biology of the
University of Malta keeps track
of new species appearing in local
waters.
Discoveries of new species in
Maltese waters often turn out
to be records of non-native (or
‘alien’) species, that is, species
which do not occur naturally in
our waters but were directly or
indirectly introduced here through
human activities. Colonisation
by non-native species very often
represents a threat to indigenous
marine life since alien species can
compete directly or indirectly with
native biota, may modify habitats,
or lead to the introduction of
new parasites and pathogens.
Alien species can also impact the
economy or even human health:
little wonder therefore that reports
of new pest seaweeds, poisonous
fish or venomous jellyfish attract
public attention.
Documenting the arrival of
such newcomers is an important
scientific endeavour, and the
Marine Ecology Research Group
(MERG) at the Department of
Biology of the University of Malta
has been at the forefront of this
work for more than a decade.
However, recording new species is
only part of the story. For instance,
some alien species have only been
spotted once or twice and never
sighted again (these are referred to
as ‘casual’ species), and therefore
do not represent a major ecological
threat. On the other hand, other
species now occur as reproducing
and self-perpetuating populations
in the wild (‘established’ species),
and some of these have undergone
a very rapid growth of the
population to the extent that they
affect the diversity or abundance
of native species and the ecological
stability of the ecosystem (‘invasive’
species). The latter are clearly
of greater concern. To monitor
changes in the status of non-native
species in Maltese waters, CONT>
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AUGUST 2015
MERG researchers have been undertaking regular
biological surveys.
For management purposes, it is necessary to go
beyond records and studies of individual species and
to look at the broader picture. How many non-native
species occur in Maltese waters? Which plant or animal
groups do they belong to? Have they managed to
establish themselves? How are they getting here in the
first place? To answer these questions, Dr Julian Evans,
Ms Jacqueline Barbara and Prof Patrick J Schembri
have recently undertaken an extensive survey of the
scientific and other literature recording the presence
of new marine species in Maltese waters. These
data were then combined with other authenticated
but unpublished reports of such species, including
sightings made during the ongoing biological surveys
by the MERG team.
From this review it resulted that by the end of last
year, 61 authenticated alien species and another 5
unconfirmed ones had been recorded from Maltese
waters. Analysis of the known or probable mode of
arrival of these species indicated that most common
mode of introduction is through boating and shipping.
Other species were first introduced elsewhere in the
Mediterranean and then managed to spread to Maltese
Islands under their own steam. Thirty of these records
were made since the turn of the century, clearly
indicating that the rate of new records is at an all-time
high. This is likely due to the present day warming
trend of Mediterranean surface water, which favours
the occurrence, establishment and range extension
of warm-water species in the central Mediterranean.
In fact, the MERG researchers have also documented
another phenomenon – the spread of Atlantic warm-
2
water species to the central Mediterranean – which is
almost certainly related to this warming trend. To date,
7 such species have been recorded from the Maltese
Islands, so the total number of new species (aliens +
Atlantic range extenders) now stands at 73 species.
Overall, the most represented groups were
molluscs (21 species), fish (15 species), crustaceans
(8 species) and red algae (7 species). More than half
of the newcomers (38 species) have established
breeding populations, while a further 8 species are
considered to be invasive. These species are the
seaweeds Lophocladia lallemandii, Womersleyella
setacea and Caulerpa cylindracea, the bivalve
Brachidontes pharaonis, the crab Percnon gibbesi,
and the fish Fistularia commersonii, Siganus luridus
and Sphoeroides pachygaster. The latter species, a
pufferfish, is particularly interesting because it is one
of the Atlantic species that have extended their range
to reach the central Mediterranean independent of any
human involvement, and is therefore not considered
to be an alien species. Although recognition of the
threats posed by invasive species has resulted in the
inclusion of management of such species in a number
of recent policy actions, including local and EU
legislation, these legal documents refer exclusively to
“alien” species. The Maltese researchers have argued
that all newcomer species have the propensity to
disrupt native ecosystems, irrespective of whether
they are considered to be “alien” or “naturally rangeexpanding” species. Therefore, although humans
were not responsible for the introduction of rangeexpanding species, for management considerations,
assessment and monitoring of such species is as
important as for invasive alien ones.
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AUGUST 2015
UoM at Paris climate change scientific
conference
Mr Stefano Moncada presented the findings of his
Ph.D. research at a Paris climate change scientific
conference entitled ‘Our Common Future Under
Climate Change’ which was among the biggest events
of this nature held in recent years. Mr Moncada who
is an assistant lecturer at the University of Malta’s
Institute for European Studies, is also in the final stages
of his Ph.D. with the Department of Economics, FEMA.
Mr Moncada’s presentations dealt with climate
change adaptation and development in informal
urban areas, focusing on the effect of a biogas water,
hygiene and sanitation project on the adaptive
capacity of vulnerable communities in Ethiopia.
Mr Moncada also co-authored two other papers, the
first with Professor Lino Briguglio, Director of the Islands
and Small States Institute, on the ‘Vulnerability/Resilience
Framework Approach’, assessing the risks of being
harmed by climate change health impacts. Professor
Hilary Bambrick, from the University of Western Sydney,
presented the second co-authored paper entitled
‘Managing climate-sensitive health risks in vulnerable
Pacific Island communities: Lessons from Rabi Island’.
More than 2,000 scientists from over 100 countries
attended the Paris conference. The objective was to
inform the upcoming Conference of the Parties (COP21)
of the United Nation Framework Convention on Climate
Change (UNFCCC) scheduled for this autumn, also in Paris.
Cliff face collapse at Delimara
The seismic station at Wied Dalam, Birzebbugia,
operated by the Seismic Monitoring and Research
Group within the Department of Geosciences,
University of Malta, recorded a strong signal at 16:58
local time (14:58 GMT), on 09 August 2015, at the same
time as the cliff face collapse at Delimara. The signal
was also recorded at the seismic station installed at
the University, Tal-Qroqq. The SMRG operates a third
station in Gozo, which did not record the signal. The
signal appears not to be due to an earthquake but to the
impact of the cliff face collapsing onto the shore below.
A series of small earthquakes occurred the previous
week off the southern coastline but it is not likely that
there is a correlation between these two occurrences.
This newsletter is published by the Communications and Alumni
Relations Office within the University of Malta.
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