Environmental Engineering Reference
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which is widely distributed in the Bay of Bengal (Tomascik
1997
). Some of the
other crab species recorded are
Atergatis integerrimus, Matuta lunaris
,
Matuta
planipes
,
Charybdis feriatus
,
Portunus pelagicus
,
Portunus sanguinolentus
,
Scylla
serrata
,
Thalamita crenata
,
Dotilla myctiroides
,
Ocypode ceratophthalma
and
Carcinoscorpius rotundicanda
(UNDP
2010
).
The fi sh and fi sheries resource of the St. Martin's Island of Bangladesh is
undoubtedly very rich in terms of species diversity. A total of 234 species of fi sh
have been identifi ed from the waters around the island, 89 of which are coral associ-
ated species, and only 16 of which are freshwater fi sh (UNDP
2010
). The most
abundant coral or reef associated fi sh are Damsel, Parrot, Surgeon, Groupers,
Snappers, Emperors and Butterfl y fi sh (Feeroz
2009
).
A total of 27 reptile species from 11 families of three orders have been recorded
from the island; of them 11 species are locally threatened (Tomascik
1997
). Three
species of marine turtles,
Lepidochelys olivacea, Eretmochelys imbricate,
and
Chelonia mydas
, are known to nest on the island. The island supports four amphibian
species: the Common Asian Toad (
Bufo melanostictus
), and three frog species:
Euphlyctis cyanophlyctis
,
Hoplobatrachus tigerinus
and
Polypedates maculatus
.
The site lies on the boundary or overlap zone of the East Asia-Australasian
Flyway and the Central Asian Flyway and provides a stepping stone for a number
of migratory wader or shorebird species. A total of 120 species of birds have been
recorded from the island (77 resident species and 43 migratory species) of which
18 species may be classifi ed as locally threatened (Tomascik
1997
; Moudud 2009 ).
A total of 19 species of mammals were reported from the St. Martin's, of which
dogs are the only land-based carnivorous animal living in the island. The waters
around St. Martin's Island are considered likely to be visited by six species of
marine mammals or cetaceans:
Sousa chinensis, Neophocaena phocaenoides
,
Orcaella brevirostris
,
Tursiops aduncus
,
Stenella attenuate
and
Stenella longirostris
(UNDP
2010
).
Environmental Threats to Biodiversity and Ecosystem
Climate Change Impacts
The effects of global climate change pose signifi cant threats to the biodiversity of
St. Martin's Island. The most noticeable damage caused by high sea temperature is
coral bleaching. Coral bleaching turns into colourless ugly coral. Coral reefs have
already suffered major mortalities as a result of high-temperature events. It is also
dependent on a species of algae that lives symbiotically in its body and produces
additional food by photosynthesis. When the sea temperature rises above 28 °C, the
coral expels the algae and consequently it starves (Rahman
2009
). Sea-level rise
causes erosion of turtle nesting beaches. Higher sand temperature leads to changes
in sex ratios or prevent eggs from hatching. Coral reefs are essential feeding habitats
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