Effects Of Mangrove Destruction In Mumbai Environmental Sciences Essay

Rapid enlargement of urban infinites has caused force per unit area on delicate ecosystem of the metropolis. Uneven growing of assorted parts has made migration a serious challenge. Increasing population growing of metropolitan has created concretization of island metropolis and glade of critical flowered resources.

Thousands of people from assorted parts of the state come to Mumbai every month. Around 43 per cent of metropolis ‘s population considered to be migratory. The prevailing migrators are of rural beginning, coming from assorted parts of the state, with two-third to three-quarterss of all migrators belonging to this class. There are migrators from other states as good but these have been less than one per cent since 1981 ( Census ; 2001 ) . This tendency migration is a Destruction of Rhizophora mangle that was the home ground of several species of fishes have combined to go forth the metropolis ‘s fisher common people of around 50,075 ( Marine Fisheries Census ; 2005 ) panting for endurance. Among assorted grounds economic factors have been the major cause for migration to Mumbai. About 69 per cent of males stated that employment was the chief motivation behind their motion. The information show that the rate of migrators in hunt for better employment has been higher in the late ninetiess. Social grounds such as matrimony and attach toing the household constituted about 90 per cent of female migration. ( Singh 2001 )

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Population force per unit area is continuously increasing in the coastal country, so because of this spread outing population Rhizophora mangle is confronting important force per unit area of devastation. Mangroves have been cleared and degraded on an dismaying graduated table during the past four decennaries ( Valiela et al. , 2001 ; Wilkie and Fortuna, 2003 ; Duke et al. , 2007 ) , yet they remain an of import beginning of wood and nutrient merchandises and supply vitally of import environmental services for coastal communities throughout the Torrid Zones ( Balmford et al. , 2002 ) .

Climate and Rainfall

Kolis of Mumbai

Kolis are the traditional fishing community of Mumbai and are the original dwellers of the island metropolis. Fishing is still the chief beginning of their support. The interesting fact is that, Mumbai is derived from the Koli word, ‘Mumba ‘ , which means goddess of H2O. Several records reveal that Kolis have been found in Mumbai from early times. Dr. Gerson district attorney Cunha in the book ‘Origin of Mumbai ‘ describes old Mumbai as ‘the desolate islet of the Mumbai Koli fishermen. The Kolis are reported to hold occupied the land in A.D. 1138 The Koli community has several subcastes, the outstanding 1s are Koli kolis, Mangela Kolis, Mahadeo kolis, Suryawanshi kolis, Vaity kolis, Koli Christians. Kolis are divided into two occupational categories ;



Dolkars are normally rich compared to Vatsad among Kolis. Dolkars pattern angling on big graduated table Vatsads, who are a hapless category of fishermen normally in the employ of the richer members of the community. Work force are largely engaged in angling while, adult females take attention of lodging activities and merchandising of fish in the local market. Lot of their day-to-day activities depend on the fishing season and tidal motion. Koli is the chief linguistic communication spoken by the community, Marathi is another often used linguistic communication among Kolis.

What are Mangroves?

Mangroves are a group of trees, thenars, bushs, vines and ferns that portion a common ability to populate in boggy saline dirt. These workss have developed unusual versions to the alone environmental conditions in which they are found. Mangrove can be typically refered to an single species. Footings such as Rhizophora mangle ecosystem, mangrove forest, mangrove community and mangrove swamp are used interchangeably to depict the full Rhizophora mangle community ( Smithsonian Inst. 1996 ) . There are around 80 species of Rhizophora mangles found throughout the universe ( Saenger et al. , 1983 ) . Largely they occur within tropical and semitropical coastal countries subjected to tidal impact. Tidal country can be interpreted to intend a shoreline inundated by the extremes of tides, or it can more widely mention to river-bank communities where tides cause some fluctuation in H2O degree but no alteration in salt ( Tomlinson, 1986 ) .

There are chiefly two types of Rhizophora mangle ; sole and non-exclusive. Exclusive Rhizophora mangles are the largest group, consisting about 60 species ( Saenger et al. , 1983 ) . These Rhizophora mangles are confined to intertidal countries. Rest 20 species are referred as non-exclusive. Non-exclusive Rhizophora mangles differ from the sole Rhizophora mangle in the sense that these turn sooner in drier and more tellurian countries.

Features of Mangrove

Mangrove Distribution

Mangrove woods comprise up to 50 species of woody halophytes restricted to sheltered saline tidal countries, and one time occupied around 75 % of tropical seashores and recesss ( Ellison 1997 ) . Mangroves are the plats of tropical sheltered shores. Mangroves are found throughout the universe between latitudes 32A°N and 38A°S. The upper and lower bounds of this scope are determined by temperature ( Chapman, 1976 ; Tomlinson, 1986 ) .


( Beginning: ENVIS, 2008 )

Mangrove Distribution in India

Harmonizing to the Government of India, the entire country of the Rhizophora mangles in India was about at 6,740 sq. Km. this covered about 7 % of the universe mangroves ( Krishnamurthy, 1987 ) and about 8 % of the Indian coastline ( Untawale, 1987 ) . But recent 2005 information of Survey of India, Dehradun shows an extent of 4,445 sq. kilometer. mangrove countries in India. Out of the entire land area, 57 % of the Rhizophora mangles are found on the East Coast, 23 % on the West seashore and the staying 20 % on Andaman and Nicobar Islands.

Table: State/UT wise Mangrove Cover Mangrove Cover Assessment 2001 ( Area in sq. km. )

SL No.





% of Geographical Area


Andhra Pradesh




































Tamil Nadu






West Bengal






Andaman and Nicobar
















( Beginning: ENVIS, 2008 )

Mangrove Distribution in Maharashtra

Maharashtra has 720 kilometer long coastline, which has assorted characteristic characteristics of beaches and bouldery drops flanked by estuaries and spots of Rhizophora mangles. Maharashtra coastal zone extends between the latitude 15 52’N and 20 10’N and longitude 72 10’E and 73 10’E and falls under five territories of Thane, Mumbai, Sindhudurg, Raigad, Ratnagiri. The Rhizophora mangles of Maharashtra are the most diverse among the West seashore and harmonizing to the Forest Survey of India ( FSI ) covered 116 sq. kilometer in 2003. The country under Rhizophora mangles in Maharashtra was 200 sq. kilometer. in 1972-75, which reduced to 108 sq. kilometer. in 1997.

Mangroves of Mumbai

Mangrove along the seashore of Mumbai ever faced the challenge of assorted anthropogenetic activities over the decennary. In early 1890ss around 37 sq.km. Of Rhizophora mangle existed in Mumbai, largely in Versova, Gorai, Mahim brook, Thane and Ghodbunder. Some sparsely covered spots of Rhizophora mangle are besides found in Bandra, Colaba, Mahul and Malabar Hill.

The most commonly happening species of Rhizophora mangle in Mumbai is Avicennia marina, this covers the about 60 per cent of species diverseness. The characteristic characteristic of Avicennia marina makes it tolerable for high salt country. This species besides tolerates pollution including heavy metals such as lead, quicksilver and Cr.

Table: Some of the commonly found Rhizophora mangles in Mumbai

( Beginning: Kulkarni, 2007 )


Mangroves largely occur in countries where the mean temperature of the coldest month is higher than 20A°C and the seasonal scope does non transcend 10A°C. Lower temperature and hoar besides limits the growing and distribution of Rhizophora mangle ( Tomlinson, 1986 ) .


Coastal countries which receive ample sum of rainfall, heavy overflow and ooze into the intertidal zone from the backwoods are most suited for Rhizophora mangle. These countries receive extended deposit which provides immense measure of foods, which in bend are favorable for Rhizophora mangle growing ( Tomlinson, 1986 ) .

Importance of Mangrove

Multifaceted importance of Rhizophora mangle has been realised in recent times but its ecological importance is known to scientific community since 100s of old ages. Importance of Rhizophora mangle can be loosely classified under following caputs:

Ecological Importance

Mangroves are considered to be the most productive natural ecosystem throughout the universe. Mangrove ecosystem comprise of legion assortments of vegetations and zoologies. Mangrove forest consist of 70 taxonomically diverse tree, bush, thenar and fern species under 27 genera, 20 households, and nine orders that portion a suite of convergent versions to saline, anoxic home grounds ( e.g. Tomlinson, 1986 ; Stewart & A ; Popp, 1987 ; Ball, 1988 ; Duke et Al, 1998 ) .

Economic Importance

Mangroves provide a huge scope of wood and non-wood wood merchandises which are of good economic value such as lumber, fuel wood, medical specialty, thatch, honey, fresh fish, wood coal etc.

Legislative Framework for Conservation and Management of Mangrove in India

The Indian Forest Act, 1927: Supply protection to “ flora and fauna ” . The Indian Forest Act has been applied to the Rhizophora mangle wood of the Sundarbans, which have been declared as a “ Reserved Area ” .

The Wildlife ( Protection ) Act, 1972: Supply protection to “ flora and fauna ” . Although they do non specifically mention Rhizophora mangles, these Acts of the Apostless can besides use to the preservation of the vegetations and zoologies of Rhizophora mangle ecosystem.

The Forest Conservation Act, 1980: States that “ No forest country shall be diverted for any non-forestry intent ” without anterior blessing of the Government of India. This act has proved really effectual in forestalling recreation of Rhizophora mangle forest country for non-forestry intent.

Coast Guard Act, 1978: The concern for “ Marine and Coastal Waterss ” has led to formation of a particular force, The act stipulate that Cost guard should battle oil pollution beyond 5 kilometers in the sea and execute surveillance responsibility against international dumping of oil or waste by ship/tanker.

The Environmental ( Protection ) Act, 1986: It has a important function in the Conservation and Management of Rhizophora mangle ecosystem. It declares a “ Coastal Regulation Zone ” notified in 1991, in which industrial and other activities such as discharge of untreated H2O and wastewaters, dumping of waste and land renewal are restricted in order to protect the Coastal environment.

Condition of Mangrove in Coastal Regulation Zone

It is stipulated that in instance of Rhizophora mangle with an country of 1000 sq.m or more, would be classified as CRZ with a buffer zone of at least 50 thousand Mangrove is a tropical tree growth, along the seashore and requires saline H2O for its growing. Expert in this field say that Rhizophora mangle are really of import along the seashore for breakage of tides and it is valuable resources holding several direct utilizations. Hence proper the protection of Rhizophora mangle is really of import. ( Chauhan, 2004 )

Prohibited Activities in the Coastal Regulation Zone

( a ) Setting of new industries and enlargement of bing industries ( except those straight related to waterfront or straight necessitating for shore installations ) .

( B ) Industry, managing, storage or disposal of risky substances.

( degree Celsius ) Puting up and enlargement of fish treating units including warehousing

( vitamin D ) Discharge of untreated wastes and wastewaters from industries, metropoliss and other human colonies.

( vitamin E ) Dumping of metropoliss and town wastes for the intent of land filling.

( degree Fahrenheit ) Dumping of ash or any wastes from thermic power station.

( g ) Land renewal bunding or upseting the natural class of saltwater with similar obstructors except those required for control of coastal eroding.

( H ) Mining of littorals, stones and others sub strain stuffs except other minerals non available outside the CRZ countries.

( I ) Construction activities in ecologically sensitive countries.

( J ) Any building activities between the Low Tide line and high tide line except in permitted countries.

( K ) Dressing or changing of sand dunes, hills natural characteristics including landscape alterations.

Regulation of Permissible Activities in Coastal Regulation Zone

1. Clearance shall be given for any activities within the CRZ if it requires waterfronts and bow shore installations.

2. The undermentioned activities will necessitate environmental clearance from Ministry of Environment and Forest Govt. of India.

a ) Construction activities related to defense mechanism demands for which bow shore installations are required ( e.g. Breakwaters etc. ) .

B ) Operational buildings for ports and seaports and beacons necessitating H2O frontage Jetty, waves quays etc.

degree Celsius ) Thermal Power Plants ( merely foreshore installations for conveyance of natural stuffs for consumption of chilling H2O and out autumn for discharge of treated waste H2O ) .

vitamin D ) All other activities with investing transcending rupees Five Crores.

3. a ) The Coastal provinces and Union district Administration shall fix Coastal Zone Management Plans at the earliest and blessing be taken from Central Govt. in the Ministry of Forest and Environment.

B ) Within the Framework of such blessing plans the State Govt./U.T. Administration or local Authorities shall modulate all development and activities within the Coastal Regulation Zone.

Misdemeanor of Coastal Regulation Zone has been seen in assorted parts of Mumbai Metropolitan part. Several environmental militants have raised the voice against these misdemeanors.

Coastal country is critical to the prosperity of state and normally most productive countries, back uping a wealth of marine resources. With rapid industrialisation, urbanisation, attendant pollutions and consuming resources along the seashore have resulted in debasement of coastal ecosystem and decreasing the life resources. Environmentally effectual coastal zone direction requires accurate, up to day of the month and comprehensive scientific information on which policy determination can be used.

Mangrove Destruction and its Impact

Importance of Rhizophora mangle has been recognised by assorted stakeholders of the society viz. scientists, authorities, local populations of biotic and socioeconomic services. Accurate estimations of planetary deforestation rates of Rhizophora mangles are non available ; its well-known environmental and socioeconomic impacts are observed and progressively documented in coastal communities that depend straight on Rhizophora mangles, and in highland communities with economic links to the seashore.

The primary cause of devastation throughout the universe is clear cutting, illegal dumping and renewal ; these are carried for the intent of agricultural activities, aquaculture, urban enlargement, and resort development and have threatened the bulk of Rhizophora mangle ecosystem. This devastation worsening economic emphasis of mostly low-income, fast turning local population, who are driven to work Rhizophora mangles despite clear marks of debasement.

Mangrove woods are a beginning of support for 1000s of coastal communities in developing states worldwide ; these communities traditionally harvest fish, runt, lumber, non-timber wood Products, and fuel wood from them. The importance of the Rhizophora mangle ecosystem transcends purveying services and includes regulative, ecological, cultural, and aesthetic services. However, these services are decreasing globally, most particularly the provisioning service, and this is seting the supports of coastal communities at hazard and increasing their exposure to tropical storms and rushs. These tendencies are the result of mounting anthropogenetic activities such as brackish H2O aquaculture, mangrove forest glade for substructure development and varied degrees of reaping for subsistence.

Because of these force per unit areas, Rhizophora mangles in coastal tropical developing states are being degraded ; for case, 20-30 % of Rhizophora mangle woods have been lost in West-Central Africa since 1980 ( UNEP-WCMC, 2007 ) .

Mangrove and Fishing

Linkages Between Mangrove and Fishing

Fishs and invertebrates use estuarial and onshore home grounds in a figure of ways: some are lone occasional visitants ; some use them merely at certain life phases, whereas others reside for good in the estuaries ( Lenanton & A ; Potter 1987, Potter et Al. 1990, Potter & A ; Hyndes 1999, Whitfield 1999 ) .

There are assorted groups of fishes and invertebrates which show distinguishable association with Rhizophora mangle. Fishes which are found on occasion in estuaries are termed as Marine strayers ( Potter & A ; Hyndes 1999, Whitfield 1999 ) and these strayers have least dependance on estuaries.

There are species which uses estuaries and inshore parts for important clip period particularly during juvenile phase merely. In some marine species juveniles are merely found in Rhizophora mangles and these are termed as Rhizophora mangle dependant species ; e.g. , banana shrimp P. merguiensis ( Staples et al. 1985, Vance et Al. 1996 ) . Catadromous species travel between fresh and marine H2O besides use mangrove home grounds at certain life phases e.g. , barramundi Lates calcarifer ( Russell & A ; Garrett 1983 ) . Some species spend their full life rhythm in estuaries and are termed as true estuarine species.

The importance of Rhizophora mangle for prolonging production of piscary in coastal ecosystem is a widely held paradigm that mangroves act as of import baby’s room sites for piscaries species. The map of Rhizophora mangles as baby’s room sites is widely accepted ( e.g. , Blaber 2000, Kathiresan & A ; Bingham 2001 ) and this paradigm is used for of import direction determinations on home ground preservation and Restoration of Rhizophora mangle ( Beck et al. 2001 ) . There are besides theories that provinces ; country of Rhizophora mangle home ground in an estuary translates to the secondary production and gimmick of commercial piscaries ( Baran 1999 ) . There are clear instances of illustration which depict the correlativity between the magnitude of commercial finfish gimmicks and the extent of Rhizophora mangles. For illustration, in the Philippines, a positive, but weak, correlativity was found between mangrove country and the gimmick of four households of commercial fish ( Paw & A ; Chua 1991 ) .

Freshwater Mangrove Marine

Freshwater Mangrove Marine

Figure Number of fish and shrimp species happening in fresh water, Marine and mangrove ecosystem demoing higher species diverseness in the Rhizophora mangles ( Islam & A ; Haque 2005 ) .

Mangrove as nursery site for fishes:

Mangroves and estuaries portion characteristic characteristics such as shallow H2O, reduced wave action, high organic content in the deposit, high primary production and protection from marauders, which may all lend to their function as baby’s rooms. Nursery countries for fishes have been regarded as any countries inhabited by the juveniles, frequently with the grownups populating in separate home grounds. But, this definition of baby’s room is challenged by Beck et Al, ( 2001 ) ; he proposes a different image of fish baby’s rooms “ a home ground is a baby’s room for juveniles of a peculiar species if its part per unit country to the production of persons that recruit to adult populations is greater, on norm, than production from other home grounds in which juveniles occur ” . Harmonizing to this definition baby’s room is that portion of habitat country of juvenile which are most productive in footings of supply of recruits to adult populations and, hence, to piscaries.

Based on the generative form and its association with the Rhizophora mangle fishes can be classified into following four classs:

a ) Regular spawners

The spawning activity of the species occurs on a regular basis in the Rhizophora mangle. The species are non needfully resident in the part, but they ever use it to engender. e.g. S. rastrifer, B. Ronchus

B ) Occasional spawners

The spawning activity in the Rhizophora mangle is simply occasional. This part can be used to engender, but there is no grounds that a great figure of persons in this group of species use it. These species are non as abundant in the Rhizophora mangle as those of regular spawners. e.g. C. parallelus, C. edentulus

degree Celsius ) Matures in system

The spawning activity of the species does non happen in the Rhizophora mangle, but this part is frequented on a regular basis during the concluding stage of ripening. e.g. I. Parvipinnis

vitamin D ) Do non maturate in system

The spawning activity does non happen in the Rhizophora mangle, and the gonadal ripening, if present, does non happen in many single. e.g. P. corvinaeformis, P. brasiliensis

The exact function of Rhizophora mangles as baby’s rooms are non good understood but a figure of hypotheses have been proposed to explicate this function ( Robertson & A ; Blaber 1992, Blaber 2000 ) . The three chief hypotheses are that Rhizophora mangles provide juveniles with

( 1 ) Safety from marauders

Numerous piscivorous fish enter Rhizophora mangle during the high tide period ( Blaber et al. 1989, Vance et Al. 1996 ) therefore smaller fishes escape their marauders by come ining in Rhizophora mangle. This is attributed by assorted factors structural complexness of submersed flora, shallow H2O and turbidness can give important safeties from marauders, particularly for little, nomadic animate beings ( Robertson & A ; Duke 1987, Robertson & A ; Blaber 1992 ) .

Mangroves provide the protection from prey by structural complexness as Rhizophora mangle home ground is really complex structurally because of pneumatophores and fallen dust ( leaves, subdivisions and logs ) , prop roots, buttresses and subdivisions. These constructions provide protection in assorted ways: by cut downing prey visibleness, by take downing brush rate of quarry and marauder, and by restricting the ability of marauder to seek for and gaining control quarry ( Ronnback et al. 1999 ) .

Shallow H2O status does non favor the entry of big marauders therefore supplying another signifier of garbage for little fishes and crustaceans ( Boesch & A ; Turner 1984, Blaber 2000 ) . It has been observed at assorted topographic points that little fishes and shrimps moved into more shallow Waterss while larger predatory fishes remained in deeper H2O at the peripheries of the Rhizophora mangles.

High turbidness and shadow beneath the Rhizophora mangle canopy decreases the submerged visibleness. The turbid and shaded H2O frequently found around Rhizophora mangles may therefore supply an extra safety from ocular marauders ( Blaber & A ; Blaber 1980, Whitfield 1999 ) . Juvenile fishes acquire attracted to turbid countries and may utilize the turbidness gradient to turn up nursery countries. Abundances of some fish species have been found to be higher in countries of higher turbidness ( Blaber 2000 ) .

Figure: Conceptual conventional diagram of the food and energy fluxes in self-sustained Rhizophora mangle ecosystem and the interaction of Rhizophora mangle with next fresh water and offshore marine ecosystem.

( Beginning: Islam & A ; Haque, 2005 )

( 2 ) Abundance of nutrient

Nutrient content and primary productiveness are normally really high in mangrove country and nutrient handiness is more for fishes and crustaceans than any other coastal home grounds. Food comes to the Rhizophora mangle system from upstream and from seaward and they are concentrated in mangrove country by pin downing. Primary productiveness in the Rhizophora mangle forest itself attributed to several beginnings including air plants, phytoplankton, mangrove trees, and benthal microalgae ( Ronnback 1999 ) . Assorted fishes consume most of their provender when they come to the mangrove country. Primary productiveness in Rhizophora mangle wood forms the footing of a nutrient web providing abundant and varied trophic resources to higher consumers ( Baran & A ; Hambrey 1998 ) .

Mangrove forest green goods litter throughput the twelvemonth, they have the ability to bring forth big measures of litter, runing from 10,000 to 14,000 kilograms dry weight/ ha/ twelvemonth ( Hamilton and Snedaker, 1984 ) . Most animals are unable to absorb this straight and necessitate bacterial enrichment before ingestion. However, sesarmid pediculosis pubis can straight devour Rhizophora mangle litter and/or store 30-80 % of the litterfall ( Ronnback 1999 ) . These pediculosis pubiss are eaten by fishes, making a tract for Rhizophora mangle foods to come in nutrient webs.

( 3 ) Shelter from physical perturbations

Mangrove home ground is the country of low current, where impact of coastal tide gets reduced. This provides the little juvenile fishes benign physical environment to settle. Mangrove presence increases the abode clip of H2O, particularly in level, broad Rhizophora mangles with complex waterways ( Wolanski & A ; Ridd 1986 ) .

The juveniles of few species of crustaceans, such as banana shrimps Penaeus merguiensis and P. indicus ) , are found entirely in Rhizophora mangle ecosystem ( Staples et al. 1985, Vance et Al. 1998, Ronnback et Al. 2002 ) and are described as extremely mangrove-dependent.

It has been established from assorted surveies that approximately two tierce of universe ‘s fish and shellfish crop are straight linked to estuarine home ground ( Robertson & A ; Blaber 1992 ) .

Ronnback ( 1999 ) listed the proportion of mangrove-related species in piscaries in assorted parts of the universe:

Geographic Location

% of fishes dependent on Rhizophora mangle







Eastern Australia


Malacca Strait


Southeasterly Asiatic states

Fish 30 ( & A ; Prawn 100 % )





Merchandises of Mangrove Ecosystem

( Beginning: Saenger et Al, 1983 )

Mangroves of Mumbai

Mangrove Destruction

Assorted surveies confirm the devastation of Rhizophora mangle throughout the Earth and in peculiar have focused on gauging the entire country cleared, rate of glade, loss of deposits and eroding ( Hatcher et al. 1989, Valiela et Al. 2001, Alongi 2002 ) .

Figure: Proportion of bing planetary Rhizophora mangle countries and countries in the South and Southeast Asia

( Beginning: Islam & A ; Haque, 2005 )


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