Vol. 2                                   September, 2003                               No. 3


Of all the factors affecting the health and sustainability of the world’s oceans, the status of
endangered species may be one of the most familiar to the public. The reason for this may stem
from that fact this topic is often the focus of the news media. As humans, we experience powerful
emotions when faced with a steady stream of information and images on our favorite sea life –
including, whales, dolphins, manatees, salmon, turtles, sharks, and now, the white abalone – in
peril. Perhaps it is because we admire and enjoy their beauty, intelligence, or, their sheer
existence, based on thousands of years of evolutionary adaptation. However, a greater reason for
preventing the extinction of marine plants and animals is they are vital components for
maintaining life on earth.

To understand the issues surrounding endangered
marine species, it is important to explore the                        CONTENTS
meaning of biological diversity, otherwise known       Invited articles
as “biodiversity.” This is defined as the variety of      1. Mud banks of(f) Kerala……..     2
life in all its forms and the interactions among          2. Bottom trawling……….........    4
these living forms and their environment. There        Book Reviews……………………...              5
are three general kinds of biodiversity: habitat       Recent Books………………………                6
diversity, genetic diversity, and species diversity.   News Briefs………………………...              6
The survival of each is linked to the health of the    Recent Publications……………….           8
other two, and together they comprise the wealth
of ecosystems.

Endangerment is a broad issue, one that involves the habitats and environments where species
live and interact with one another. There are many reasons why a particular marine species may
become endangered. Several factors leading to endangerment are habitat destruction,
introducing exotic species, overexploitation, disease and pollution. Although some measures are
being taken to help specific cases of endangerment, the universal problem cannot be solved until
humans protect the natural environments where endangered species dwell.

  This newsletter is a quarterly non priced publication of
  ENVIS Node on “Marine Ecosystem” at Department of                              June 10, 2003
  Geology, University of Kerala, Kariavattom. The Node is
  supported by funds from Ministry of Environment and
  Forests, Government of India, under EMCBTA Project of              Prof. Thrivikramji, K. P
  World Bank. The Node is building databases on information
  related to Marine Ecosystem and expertise available in the
  region and ongoing activities. The content of the newsletter
                                                                                 Dr. A.N. Rajan
  may be quoted or reproduced for non-commercial use,
                                                                                Program Officer
  provided source is duly acknowledged. Request for
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  subscription may be sent at the address given.
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                                             INVITED ARTICLES

          Prof. Thrivikramji.K.P., University of Kerala, Kariavattom Campus 695 581


Mud banks (MB) are very special to certain segments of the coastal waters of Kerala and were
first reported by Bristo, the founder of the Cochin port. This phenomenon, not known elsewhere in
the world is of interest not only to the fishing industry and Marine biologists, but also to physical
and chemical oceanographers as well as geoscientists. The immediate attraction to the fish-
workers is the very profitable fisheries opportunities due to very special fish species attached to
the MB or fishing ground the mud banks are synonymous with. Further, such a phenomenon is
also not noticed reported from elsewhere in the country. In what follows, one would come across
a useful summary or rather a review of the various aspects the MB.

                                             Fisheries potential

The huge fisheries potential that exist in the mud banks attract hundreds of migratory fish-workers
with their crafts and tools, financiers, buyers, seasonal workers in peeling and processing units
and others like truckers, porters, small business persons who find numerous but indirect business
opportunities. Due to abundance of Prawns, sardines, mackerels and soles in the waters during
the MB season, the small and big towns in the adjacent coastal land plunges into a frenzy, and
Thakazhi Sivasankara Pillai very aptly used this canvas for his great love story – Chemmeen,
which later on Ramu Karyat immortalized in his epic film of the same name.

                                                Previous work

Ever since Bristo made the first mention during his preliminary studies in connection with the
design and development of the Cochin Port, the MB attracted the curiosity of geologists as well
as Marine Biologists. The latter always worried and wondered about its fisheries potential, and
the causative biological and physical and chemical parameters. The Geoscientist, on the other
hand focused on the mineralogy of the (silty-, clayey-) sediment in suspension on the body of the
MB, and thereby the source/s and the mechanism that triggered, maintained, even controlled the
loci. Jacob, Dora, Narayana and Nair made significant contributions on the varied geological
aspects, where as, Kurup examined the phenomenon from a Physical Oceanographers

                                                What are MB?

The MB are very special and uniquely present only in the coastal waters of Kerala and that too
these become active only during the SW monsoon season. Another, attraction of the MB is the
excellent fisheries potential they offer the fishing industry. This phenomenon appears only in the
segment between Thirkunnapuzha and Kozhikode (distance=270Km). Another important attribute
is that mud banks are migratory in nature, i.e., these migrate up coast or down coast, in that they
do not recur in the same spot or sector year after year.

Nair reports at least at 27 locations in this sector, where MB had appeared at one time or other.
The marine geology of the MB sector is generalized as below. A map of the sea bed geology of
the shelf published by Siddique, Mallick and Srivastava (1978), all of the Geological Survey of
India, shows the presence of an inner-shelf mud in the MB region, in addition to a narrow ribbon

EMCB-ENVIS Node on “Marine Ecosystem” Department of Geology, University of Kerala, Kariavattom – 695 581, INDIA
of sand lacing the sea bed from north to south – a seaward extension of the sediment in the
beach face.

Kurup reported that usually low phosphate content of the mud water rises during the MB
generating SW monsoon season, but salinity down by 8% of the normal. The June-July period is
roughest in the Laccadive Sea with highest 10% waves. Mud content in the range of 1200 mg/lit
on the surface waters of MB to 1500 mg/lit in the bottom layer exists. The mud is
characteristically made of clay (45-65%; Kaolinite, 60 to 65%; montmorillonite, 15-20%; and illite
15-20%; and traces of chlorite, quartz and gypsum), followed by silt and very little sand. The
temperature between surface and bottom waters in the MB differs only by 1.0- 1.5 o C.

In the late sixties, a Norwegian research ship had collected bottom sediment samples in the
coastal waters of the MB region. The samples archived in the KERI were studied for
characterizing the clay mineralogy, and there is a report on the presence of coarse sand grade
Selenite grains (crystals) - a transparent variety of gypsum – showing a nucleus of sand particle,
clay lumps or shell fragments.

I believe that these Selenite grains would have rather formed in the pore waters of tropical beach
sediment due to super-saturation of its pore water with respect to gypsum. Absence of such
crystals in the eroding modern beach (sediment) then must be taken as a robust evidence for the
occurrence of beach complexes (sand bodies) in the offshore that formed during the low sea level
stands in the Pleistocene. Selenite along with the mud is stirred up by the wave climate of the SW
monsoon. Kurup too supported a wave initiated triggering mechanism for the MB.

                                              Why Mud-banks?

This phenomenon offering the twin benefits of (a). rather very safe and harbour like clam pool of
water on its shore ward side, during the other wise hostile sea conditions and (b). a stupendous
fishery potential, is an important contributor to the nations GDP. Therefore, from a scientific point
of view, the mud banks are “an essential phenomenon” for the marine biologist and the Marine
Geologist. More over, a coastal sea sans MB for Kerala and the nation will be equally
devastating. The “erosion shadow” offered to the beach by the MB is equally beneficial to the
settlers in the respective backshores, as well as to the exchequer. Therefore these themes have
legitimately become a field of study to examine the sustainability of the phenomenon and
resource potential.

        The MB phenomenon has been attributed to mundane geological phenomenon like
submarine spring sapping and the sea bottom sediment stirring monsoon wave climate. However,
the investigations by various groups and individuals have come to suggest the role of waves on a
sea bed with large quantity of dominantly muddy sediment. The migratory nature of mud banks
obviously reflects the link between availability of suitable bottom mud (sediment) and wave
climate – the latter however is a trans-Laccadive sea phenomenon. The nutrient that surfaces
due to upwelling caused by the wave activity attracts marine life of sorts to this region creating a
transient but rich fishing ground.

                                              What lies ahead?

Considering the huge reserves of sandy-clayey, clayey bottom sediment that had been
accumulating since the Pleistocene (since 1.8 Ma) in the continental shelf of Kerala, the state
shall not have to worry about the rebirth of the MB in the coastal waters and hence the income
from the MB related fisheries. The chances are that the size of reservoir of mud must be on the
increase, as a result of selective shoreward transport of ilmenite rich sand (now exploited by the
Rutile manufacturing industry), leaving behind a lag sediment rich in mud.

EMCB-ENVIS Node on “Marine Ecosystem” Department of Geology, University of Kerala, Kariavattom – 695 581, INDIA
                                       Some additional readings

Anonymous, 1969. Kerala Mud Banks and shore stability: Rpt.25th Zonal Meeting, Trivandrum

Bristow, RC, 1938. History of Mud Banks: 1&2, Cochin Govt. Press, Ernakulam, 174p.
Krishnanath,R, 1970

Kurup, PG, 1969. Present status of knowledge on the physical aspects of mud bank formation
along the coast of Kerala: Mahasagar, 2(3), 25-31

Nair, ASK, Interim Report on study of Mud banks off Kerala coast, India, Tech. Rpt., 21, CESS,
Trivandrum, 20p

Nair, RR, 1976. Unique mud bank off Kerala, south west India: Bull. AAPG,60, p. 616-21.

Srivastava, PS, et al, 1968. Monthly wave characteristics of the Arabian sea: Ind. Jour. Met &
Geophy., 19, 329-330.

                                            BOTTOM TRAWLING

     A. N. Rajan, EMCB-ENVIS Node on “Marine Ecosystem” Department of Geology
                     University of Kerala, Kariavattom – 695 581

Bottom trawling is one of the most disruptive and widespread human induced physical
disturbances to seabed communities and has become a global environmental concern.

The effects of bottom trawling and use of other mobile fishing gear on the seabed resemble forest
clear-cutting, a terrestrial disturbance recognized as a major threat to biological diversity and
economic sustainability. Most structures in seabed communities are smaller than those in forests,
but are no less important to their biodiversity. Use of mobile fishing gear crushes, buries, and
exposes marine animals and their structures. It also alters biogeochemical cycles, perhaps even
globally. Recovery after disturbance is often slow, sometimes decades or more for structure-
forming species. Recent advances in fishing technology have all but eliminated the natural
refuges. The frequency of trawling (in percent of the continental shelf trawled per year) is orders
of magnitude higher than other severe seabed disturbances, annually covering an area
equivalent to perhaps half of the world's continental shelf, or 150 times the land area that is clear-
cut yearly. Mobile fishing gear can have large and long-lasting effects on seabed communities,
including young commercially important fishes, although some species benefit when structural
complexity is reduced.

Fishermen have recognized and complained about the effects of bottom trawling since the 14th
century. As early as 1366, a petition was filed with Britain's Commons to outlaw the
Woundrychoun, probably Britain's first bottom trawler, because "the long iron presses so hard
upon the ground when fishing that it destroys the living slime and plants growing on the bottom
under the water, and also the spat of oysters, mussels and of other fish, by which the large fish
are accustomed to live and be nourished." A study published in the journal “Conservation
Biology” (December 1998) by Les Watling of the University of Maine and Elliott A, Norse of
Marine Conservation Biology Institute reveals that bottom trawling is the most important source of
human-caused physical disturbance of the seabed, threatening marine biological diversity and the
sustainability of fisheries. Its impacts in the sea can be compared with those of forest clear cutting
on land, yet the area it affects is far greater.

Marine biologists know that the structural complexity of rocky reefs, boulders, cobbles and
gravels is necessary for the survival of many marine species, including juvenile fish. Scientific
studies show that trawling reduces structural complexity and eliminates nursery habitats. A

EMCB-ENVIS Node on “Marine Ecosystem” Department of Geology, University of Kerala, Kariavattom – 695 581, INDIA
diverse habitat structure is vital to a wide variety of marine life because it provides surfaces for
feeding and hiding places from predators. The young of many fish species are found near
seemingly unimportant habitat features like sand ripples, clam shells, and stationary creatures
like sponges. Not only do these natural features provide cover for commercially important species
such as cod and lobster, but also for their prey which includes crabs, small crustaceans, marine
worms, and sea urchins. Studies have shown greater survival of juvenile fish such as cod in
habitats that retain their structural complexity and decreases in species diversity in areas that
have been trawled.

Many marine organisms dig into muddy bottoms to create burrows and tubes to hide from
predators and capture food. On these bottoms, trawl gear collapses the burrows and breaks the
tubes, exposing inhabitants to predators. Some of these small species -- essential links in the
marine food chain -- are unable to rebuild their homes. Moreover, trawling re-suspends plumes of
sediment, clouding the water and potentially affecting critical natural processes such as
photosynthesis and feeding. Dredging is an even more severe disturbance as it actually digs
through the seabed to take scallops and other animals off the bottom.

Some types of fishing such as long-lining and gillnetting do not harm seafloor habitat as bottom
trawling does. However, these types of fishing reduce biodiversity by removing large amounts of
targeted commercial species plus undersized fish and other marine organisms that are caught
incidentally (known as bycatch or bykill). Bykill is a problem with most types of commercial
fishing, including bottom trawling.

                                               BOOK REVIEWS

A Field Guide to Marine Food Fishes of Andaman and Nicobar Islands / P.T. Rajan. Kolkata,
Zoological Survey of India, 2003, xiv, 260 p.,

This book is the result of consolidated information gathered since, 1990 from diverse habitats,
and from the variety and variability one encounters in the fish market at Port Blair. This book
deals with 282 commercially important marine fish species of Andaman and Nicobar group of
islands. The book intends to serve the needs of those working in field as well as in laboratories,
besides development of fishery biology in this island. The author also feels that the present work
will assist in resolving the difficulties of identification of this large group in the field and the
baseline data together with pictorial illustration given in this book will assist one and all in the field
of fishery biology.

Aquatic Ecosystems / Arvind Kumar. New Delhi, A.P.H., 2003, xi, 437 p.

This book is the unique compilation of 51 research articles contributed by eminent aquatic
biologists which will be immensely helpful for university teachers, research scholars, scientists
and for everyone dealing with aquatic environment.

Indian Seashells : Part-I: Polyplacophora and Gastropoda / N.V. Subba Rao. Kolkata,
Zoological Survey of India, 2003, x, 416 p., [Records of the Zoological Survey of India:
Occasional Paper No. 192]

The first two chapters provide general background information on the phylum mollusca such as
classification, general organization, abundance, distribution, size and diversity. The values of
molluscan diversity are explained bringing out their importance as objects of aesthetic,
commercial, food and biomedical nature and role in marine biodeterioration. The references at
the end of the chapter would provide additional information and help in further research. Chapter
3 deals with the systematic account of Polyplacophora and Gastropoda consisting of as many as
530 species belonging to 80 families. Under each class and family and some subfamilies
important diagnostic characters are given. Each species is described giving salient shell

EMCB-ENVIS Node on “Marine Ecosystem” Department of Geology, University of Kerala, Kariavattom – 695 581, INDIA
characters and also illustrated so as to facilitate easy identification. Based on the collections
available and also literature records, distribution of each species in India and elsewhere given.
Wherever possible, additional information on the status, habitat etc. of the species are indicated.
At the end of some families a few important references are cited.

Recent Books

Manual on Identification of Schedule Molluscs from India / Ramakrishna and A. Dey.
Kolkata, Zoological Survey of India, 2003, 40 p.,

Studies on the Soft Corals (Octocorallia : Alcyonacea) of Andaman Islands, Bay of Bengal
/ D.V. Rao and Kamla Devi. Kolkata, Zoological Survey of India, 2003, 99 p.

Sustainability and Management of Aquaculture and Fisheries / H.D. Kumar. New Delhi,
Daya Pub., 2003, xvi, 429 p.

                                                NEWS BRIEFS

Concerned citizens seek reclassification of Marina ecosystem, (The Hindu, April 22, 2003)

CHENNAI - Citizen's group in Chennai have joined hands to preserve the Marina ecosystem,
calling for reclassification and up-gradation of the ecologically sensitive area under the Coastal
Regulations Zone Rules.

In a memorandum to the Union Ministry of Environment and Forests, the Concerned Citizens'
Group (CCG) protests that though the Director of Environment, Tamil Nadu, in February 1998
recommended that the Marina stretch be categorized as CRZ-I (ecologically fragile area), the
State's Coastal Zone Management Plan had not taken steps to do so.

Meet on conservation of marine biodiversity (The Hindu, March 20, 2003)

NEW DELHI - Marine biologists, scientists and experts will come together in Kankyakumari, on
March 21, to evolve an action plan for conservation of marine biodiversity. The two-day national
conference organised by the Ministry of Environment and Forests will also deliberate upon
ecological security.

An ecosystem in peril by PARVATHI MENON (Frontline, Vol. 20 -06, March 15 - 28, 2003)

The Gulf of Mannar Biosphere Reserve, the biologically richest coastal region in India, is under
tremendous pressure, and the legal measures that are in place to protect it have not been quite

E.U. bans trawling for cod in Baltic waters until September (ENS, 15 April 2003)

BRUSSELS, Belgium — In an effort to protect threatened fish stocks, the European Union on
Monday banned fishers from trawling for cod and flatfish in E.U. Baltic Sea waters until

EMCB-ENVIS Node on “Marine Ecosystem” Department of Geology, University of Kerala, Kariavattom – 695 581, INDIA
Plan released to bring back sea otters and other stories (ENS, 24 April 2003)

One of the Pacific coast's most adored creatures, the California southern sea otter, had been
making a comeback after decades of severe hunting. But in recent years, the threatened animal's
population has plummeted, placing it in danger of extinction.

Seven rescued pilot whales are swimming on their own; their health is improving (ENS, 23
April 2003)

BIG PINE KEY, Fla. — Seven pilot whales rescued from shallow water in the Florida Keys were
swimming on their own as their conditions slowly improved, rescue officials said.

Marine worms clogging oil industry (Environment News, 7 May 2003)

Marine worms are the cause of a large amount of cement deposit on the sea floor, British
research has found, resulting in serious problems for the oil mining industry.

By studying the digestive powers of the marine lugworm, Arenicola marina, a team of British
geologists have overturned previous assumptions about the origin of clay minerals in marine

Dramatic rise in California sea otter deaths has wildlife officials concerned (ENN, April 29,

Forty-four southern sea otters have washed up dead on California beaches this month, a
dramatic and as-yet unexplained increase in mortalities among the threatened marine mammal

Ancient tubeworms engineer the deep sea (News in Science, 21 March 2003).

Cities of tubeworms carpeting the sea floor live for centuries by thriving on poisons seeping from
below, American researchers have discovered.

In the latest issue of the journal Ecology Letters, U.S. biologists report that vast tracts of the
Lamellibrachia luymesi tubeworms in the Gulf of Mexico thrive by absorbing hydrogen sulphide
from cracks in the seafloor that seep oil and gas.

Rebuilding an ecosystem by ASHA KRISHNAKUMAR (Frontline, Vol. 20 - 05, March 01 - 14,

The Chennai-based MSSRF launches a project to promote sustainable alternative livelihood
systems using local resources for the benefit of people living off the Gulf of Mannar coast, the
country's first community-managed artificial coral reef project to stimulate the natural system that
has degraded over the years, in order to bring thousands of fishermen families out of poverty and

Pew Report Finds U.S. Oceans in Crisis (ENS, June 4, 2003)

WASHINGTON, DC- The nation's oceans are in crisis from overfishing, pollution and
development, and the government's patchwork of laws and bureaucracies are failing to protect
them, according to an independent report released today.

EMCB-ENVIS Node on “Marine Ecosystem” Department of Geology, University of Kerala, Kariavattom – 695 581, INDIA
Post cabinet press briefing- Chief Minister A. K. Antony informed the press that like in the past
years Government will declare a ban on trawling for 45 days beginning June 15, 03. He also
added that all the non Kerala trawlers operating in Kerala must leave the coastal waters positively
before the deadline of June 15th.

Some recent publications in journals related
to marine ecosystem.

Ansari Z. A; R. A. Sreepada; S. G. Dalal; B. S. Ingole and A.
Chatterji. 2003. Environmental influences on the trawl catches in

                                                                                PRINTED MATTER - BOOK POST
a bay-estuarine system of Goa, west coast of India. Estuar.
Coast. Shelf Sci., 56 (3-4): 503-515.

de Boer W. F. and H. H. T. Prins. 2003. The community structure
of a tropical intertidal mudflat under human exploitation. ICES J.
Mar. Sci. 59(6): 1237-1247.

McQuoid M. R. and K. Nordberg. 2003. The diatom Paralia
sulcata as an environmental indicator species in coastal
sediments. Estuar. Coast. Shelf Sci 56(2): 339-354.

Acosta C. A and D. N. Robertson. 2003. Comparative spatial
ecology of fished spiny lobsters Panulirus argus and an unfished
congener P. guttatus in an isolated marine reserve at Glover's
Reef atoll, Belize. Coral Reefs 22 (1): 1-9.

Yue Che, Qing He, and Wei-Qing Lin. 2003. The distributions of
particulate heavy metals and its indication to the transfer of
sediments in the Changjiang Estuary and Hangzhou Bay, China.
Mar. Pollut. Bull. 46 (1): 123-131.

Derek V. Ellis. 2003. The concept of "sustainable ecological
succession"; and its value in assessing the recovery of sediment
seabed biodiversity from environmental impact. Mar. Pollut. Bull.
46 (1): 39-41.

Shinsuke Tanabe. 2003. Contamination and toxic effects of persistent endocrine disrupters in marine
mammals and birds. Mar. Pollut. Bull., 46 (1): 69-77.

Connell D. W; G. Miller and S. Anderson. 2003. Chlorohydrocarbon pesticides in the Australian marine
environment after banning in the period from the 1970s to 1980s. Mar. Pollut. Bull., 46 (1): 78-83

Silke Kröger, Sergey Piletsky and Anthony P. F. Turner. 2003. Biosensors for marine pollution research,
monitoring and control. Mar. Pollut. Bull, 46 (1): 24-34.

Prof. Thrivikramji, K.P.                                              Phone : +91-471-2418403
Department of Geology                                                 E-mail :
University of Kerala                                                 
Kariavattom, Thiruvananthapuram – 695 581

Available online at: http//

  Printed at: Aswini Printers, Kalady, Karamana P.O, Trivandrum Ph: 0471-2343907

EMCB-ENVIS Node on “Marine Ecosystem” Department of Geology, University of Kerala, Kariavattom – 695 581, INDIA

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