THE INDUS DELTA MANGROVE ECOSYSTEM AND RRIDM (Rehabilitation and Replanting of the Indus Delta Mangroves) ACTIVITIESNurudddin Mahmood and Qadeer Mohammad AliInstitute of Marine Sciences, University of Chittagong, Bangladesh; Marine Reference Collection and Resources Centre, University of Karachi.

ABSTRACT

The Indus delta mangrove ecosystem extends over an area of about 600, 000 hectares on the coast of Sindh, between Karachi and the south-western border of India. It is a typical fan shaped delta built up by discharge of large quantities of silt washed down from the Karakoram and Himalayan mountain ranges by the river Indus. It consists of creeks, extensive mud flats, sand dunes, salt marshes and mangroves. An estimated 1,35, 000 people depend on this ecosystem for their livelihood and harvest its natural resources for various purposes such as fishing, camel browsing, buffalo grazing and wood collection etc. Fishery is the principal sector in terms of economic value (98%), but it is under serious pressure as a result of over fishing, non judicious fishing techniques, reduction in sweet water flow through the Indus, pollution and changes in hydrography, degeneration of mangrove vegetation and habitat. The need to conserve and rehabilitate the valuable resources of this ecosystem has been correctly recognised by the GoS, since there were/are clear signs of degradation of water, mangrove and fish resources. This awareness resulted in formulation of the Rehabilitation and Replanting of the Indus Delta Mangroves (RRIDM) sub project, which was started in 1993 by the Coastal Forest Division, Sindh Forest Department with the help of fund provided by the GoS and the World Bank. The project has succeeded in establishing about 16, 000 hectares of mangroves over a period of 6 years equally spread over 3 ranges: Karachi 5,108ha, Keti Bundar/Karochan 5,617ha and Shah Bundar 5,275ha. Taking the advantage of a small fund from this project the Marine Reference Collection and Resource Centre, University of Karachi in collaboration with the Coastal forest Department, Sindh has given a big step to initiate research works on Marine Biological aspects with emphasis on FISHERIES OCEANOGRAPHY. The results underline the importance of the Indus delta mangrove ecosystem as an ideal habitat of fishery and other valuable resources.

KEY WORDS: Indus delta mangrove rehabilitation.

Introduction

The Indus delta mangrove ecosystem extends over an area of about 600,000 hectares on the coast of Sindh, between Karachi and the south-western border of India (Fig. 1). It is a typical fan shaped delta built up by discharge of large quantities of silt washed down from the Karakoram and Himalayan mountain ranges by the river Indus. It consists of seventeen major creeks and extensive mud flats, sand dunes, salt marshes and mangroves (Table 1). The Indus delta mangroves are perhaps unique in being the largest area of arid climate mangroves in the world. An estimated 135,000 people are depending on the resources of this ecosystem for their livelihood (Shah, 1998), and it supports a variety of lives. This mangrove vegetation is characterised by a woody formation consisting of Avicennia marina, Ceriops tagal and Aegiceras corniculatum. This vegetation is commonly found in the mangrove areas, however the density differs considerably between the different subsystems (Karim, 1997). Avicennia marina is dominant and occurs as an almost monotypic stand throughout the area. This species attains a height of about 10m in the regularly inundated areas fringing the creeks or in the trough formed in the centre of the islands. With the increase in elevation and decreasing flooding frequency by the tidal waters the height of the tree is greatly reduced and takes and stunted bushy appearance. Aegiceras corniculatum and Ceriops tagal are found to occur in the relatively high ground particularly along the raised levees. In the soft muddy substratum being regularly inundated by tidal water a type of grass-vegetation forms. In many areas this vegetation covers extensive mud flats, and serves to categories a distinct stage of vegetation development (Karim, 1997). This grassland community is considered to be a pioneer stage in mangrove succession, although in many cases it is not an obligatory stage in the process of mangrove colonisation.Table 1: Area and vegetation cover of the Indus delta mangrove ecosystem

Type Area (ha)

Dense mangroves 68,100 Medium cover mangroves 58,500 Sparse cover mangroves 31,900 Total mangrove cover 158,500 Mud flats with or without vegetation* 382,700 Sand* 29,300 Creek areas* 23,600 Salt pans 1,100___ Total 529,200__Source: Farah and Meynell, 1992

*The creek area, mud flats and sand area can vary according to the tidal status. The 1990 image was taken at low tide and there fore, shows a rather small creek area as compared to that taken at high tide in 1977, which estimated the total creek area at 162,000 ha. Different species of shell and finfishes use this mangrove ecosystem as feeding, breeding and nursery ground. It also provides an excellent habitat for snakes, birds and mammals. Migratory birds find shelter here during winter. Some of the most common animals cited by villagers include pelicans, flamingos, kites, herons, egrets and jackals and dolphins (Shirkat Gah, 1997). This paper sums up the results of a rapid diagnostic study of the Indus delta mangrove ecosystem based on a review of the available literature, field studies and interviews with villagers and key informants being funded by the GoS and the World Bank under the ‘Rehabilitation and Replanting of the Indus Delta Mangroves’ (RRIDM) sub project in 1997 and 1998 (Hoekstra et al, 1997; Karim, 1997, Mahmood, 1997; Shah, 1998). The main communities living on the fringes of the creeks or within the ecosystem are the Mir Bahar and the Jats. An estimate of the coastal communities being dependent on the resources of the ecosystem was made by the RRIDM project (Shah, 1998) figured at 135,000 of which 72% live in the urbanised Port Qasim sub-system. The study identified 6 major subsystems (Table 2 and Fig. 1) on the basis of differences in available resources and use intensity as illustrated in Hoekstra et al. (1997).

Table 2: Names and locations of the sub-systems in the Indus delta

Names Boundaries (creeks) Port Qasim Waddi Khuddi and Korangi East Karachi Dabbo Creek and Waddi Khuddi Keti Bundar Turshian River and Dabbo West Shah Bundar/Karochan Wari Creek and Turshian River Central Shah Bundar Kajhar Creek and Kharak (Wari)
Source : Hoekstra et al. 1997

The uses and economic importance of this ecosystem: Natural resources of this ecosystem are harvested by the local communities for a variety of purposes as described below.

Fishing

Fishing is the main source of employment and income for the people residing in villages within and around the Indus delta mangrove ecosystem. In the most populated system near Karachi (Post Qasim), studies showed that 73% of the population is engaged in fishing activities (IUCN, 1987; 1992). The RRIDM diagnostic interviews indicate that fishing is also the main occupation in other sub systems. Furthermore, fish processing and trade provides employment to a substantial population outside the delta. Following the world-wide demand of fishery products the fishing activities expanded and intensified with modernisation of the fishing fleet during the last two decades. Most of Pakistan’s commercial marine fishery operates on the coast of Sindh, where fishing occurs within the mangrove creeks and in the neritic waters off the mouths of creeks. The marine fishery of Pakistan relies greatly on shrimps, being the most important of all the categories in terms of value of landing. This lucrative foreign exchange earning commodity highly influenced the development of fishing crafts and gears in the country especially along the coast of Sindh, and this development during the past three decades was predominantly aimed as catching more and more shrimp stocks. It was estimated (in 1997) that the value of shrimp caught at the coastal waters of Sindh was around Rs 2,834 million, while the value of mangrove dependent /loving finfish during the same year was Rs 780 million. Export value of shrimps was around US $ 100 million (= about 97% of Pakistan's total shrimp export value). Besides these, export of mud crabs Scylla serrata contributed about Rs 120 million (= US $ 3 million) to the export earnings in 1997. Following the worldwide demand of fishery products fishing activities expanded and intensified with modernisation of the fishing fleet during the last two decades. Local communities got attracted to fishing and now most villagers derive the bulk of their income from fishing, trade and processing.

Importance of mangroves to the marine fishery:

The mangrove loving shrimps and finfishes found elsewhere (Singh, 1996) are also very common here (in commercial catches) e.g., penaeid species of the genera Penaeus (JAIRA) Metapenaeus (KALRI), Parapenaeopsis (KIDDI), and the major groups of finfishes e.g., mullets, grunters, croakers, shads, groupers, snappers, cat fishes, cat fish eels, anchovies, pomfrets, trevallies, barracudas, threadfins and therapons etc. (Mahmood and Ali, 1999) The importance of mangroves to the rich marine fishery of Sindh may be deduced from a comparison of the marine fish catch statistics of the two coastal provinces of Pakistan along with their mangrove covers and the coast line lengths (Fig. 2). For instance, although Sindh has about half the coast line length (330 km) than that of Baluchistan (645 km), but it has a great wealth of mangroves (158,500 ha), about 22 times larger than that of Baluchistan (7,340 ha). The annual average catch of shrimp (most valuable item) from Sindh coastal waters is 27,584 tons, being about 35 times larger than that of Baluchistan (795 tons). Expressed on the basis of per kilometre coastline length only about 1 ton/km is harvested in Baluchistan against 84 tons/km in Sindh (Mahmood, 1997). Similarly finfish harvest in the coastal waters of Sindh (¯X= 231,242 tons) dominates over that of Baluchistan (¯X= 103,512 tons) by a great margin. Expressed on the basis of per kilometre coastline, the catch in Sindh was nearly 5 times higher (700 tons/km) than that of Baluchistan (160 tons/km). Therefore, the underlying cause of this elevated productivity in the coastal waters of Sindh is nothing but its wealth of extensive mangroves; Saifullah (1992) also supports this view. This direct relationship is sharper in case of shrimp. Likewise the relationship of mangroves with rich fishery productivity in the coastal and offshore waters of neighbouring and other countries has been also reported by several authors (McNae, 1974; Martosubroto and Naamin, 1977; Turner, 1977; Krishnamurthy and Jeyaseelan, 1984; Mahmood, 1995, Singh, 1996). Thus, it will be better for us to say ‘manage and rehabilitate mangroves to sustain the marine fishery of Pakistan’ instead of saying (Ahmed, 1985) "no mangroves no shrimps; does not apply to the West Coast of India and Pakistan." A relatively new mangrove based fishing activity is catching/holding/fattening and exportation of crabs. Export of this item has been increasing over the past years, e.g., 12 tons in 1991 to about 2,922 tons in 1997. This increase is the result of establishment of large commercial farms in Keti Bundar sub system. The stock is obtained from local fishermen being collected from the mangrove areas.

Camels browsing, buffalo grazing, fodder and fuel wood collection:

A rather unique use of the mangroves in the Indus delta is browsing of mangroves by camels, and grazing the mudflat and salt marsh grasses by buffaloes. This takes place for most of the year by herds owned by villagers living nearer to the mangroves, and also by herds from further inland areas, during monsoon. It was estimated that at present a total of 6,000 camels and 3,200 buffaloes use the ecosystem’s resources and consume about 67 million Kgs. of leaves (valuing RS 33.4 million) and 19.5 million Kgs. of grasses (valuing RS 19.5 million) respectively (Hoekstra, 1998). It has been observed that during the past decade the number of camels using the plant resources of this ecosystem has been declining. This is the result of a shift in occupation towards fishing following development of a more efficient transport system in the coastal areas, and reduction in sweet water flow through the Indus, thus making the environment less accessible to the camels. Another use of the mangroves is fuel wood collection for subsistence use and sale. It was estimated that the total quantity of wood harvested was around 12. 1 million Kgs (valuing Rs 18.9 million), it was also noted that the dependency of the local population on the wood resources has a declining trend during the past two decades (Hoekstra, 1998). A great reduction in the demand for (purchased) fuel wood has taken place in the urban fishing villages near Karachi, where 72% of the ecosystem’s human population resides. Major reason for this reduced demand is the introduction of SUI gas for domestic use and increased access of fuel wood from inland areas. In other parts of the delta, the demand for mangrove wood has also declined because of relocation of some villages further inland for want of water and degeneration of mangrove stands. The later trends have resulted in longer transport distances/costs, which is turn have made alternative sources of energy (e.g., wood from inland sources) economically more attractive.

Non tangible benefits:

Besides the tangible products, the Indus delta mangroves protect the coastal villages from tidal and wave actions especially during monsoon season, also it is claimed that the mangroves of the Post Qasim area along the creeks have resulted in a much-reduced dredging cost. This ecosystem provides an excellent habitat for many invertebrate and vertebrate fauna including plankton, nekton (e.g., the economically important shell and finfish resources) and benthos, snakes, birds, mammals and insects.

Problems and potentials:

As mentioned earlier on the economic value standpoint, the principal beneficiary of the Indus delta mangrove ecosystem is undoubtedly is its fishery (98%) operating within the net work of creeks and tidal channels fringed with mangroves, and neritic waters where the present marine fishing fleet of Sindh operates; but it faces the problem of degradation. So far this degeneration mainly manifests itself through rare occurrence of certain economically important species and therefore, reduced catches of such species (Fig. 3). During our field trips to different coastal areas of the delta we came to learn through interviews with the local fishermen that the tiger shrimp Peanaeus monodon, Palla Tenualosa ilisha and Dangri Lates calcarifer etc. (see photographs) have become rare now in south-western part of the delta. In this line of observation Mirza (1986) also recorded low species diversity in the creeks near Karachi i.e. the south-western region of the delta as compared to less saline creeks near the Indus river and the south-eastern section of the delta (Kharochan, Hajamro, Tursian and Bhuri creek). The following causes were identified (Mahmood, 1997) for degeneration of fish resources:

> Overfishing
> Non judicious fishing techniques·
> Reduction in sweet water flow through the Indus ·
> Pollution and changes in hydrography·
> Degeneration of mangrove vegetation and habitat

RRIDM activities: The need to conserve and rehabilitate theses valuable resources has been correctly recognised by the GoS, since there were/are clear signs of degradation of the water, mangrove and fish resources as stated in Hoekstra et al (1997). This awareness resulted in the formulation of the sub Project Rehabilitation and Replanting of the Indus Delta Mangroves (RRIDM). It started its activities in 1993 and was implemented by the Coastal Forest Division, Sindh Forest Department with the help of funds provided by the GoS and the World Bank.

Planting:

The project has succeeded in establishing about 16,000 hectares of mangroves over a period of 6 years, equally spread over 3 ranges, i.e. Karachi 5,108ha, Keti Bundar/ Karochan 5,617ha and Shah Bundar 5,275ha. Rhizophora mucronata was planted in most of the areas (61%) which survived well (about 80%) in most sites. An exception was a number of sites in Keti Bundar where barnacles infested the planting areas, resulting in survival rates ranging from 10 to 60%. Under good site conditions, Rhizophora reached a height of about 1.5-meter after about 6 years. Growth was much less (¯x height, around 1 meter) in the Port Qasim area where site conditions were less favourable. The second species Avicennia marina was established in 36% of the planted areas. Average survival rates of this species was also around 81%. It was observed that in the Keti Bundar sites, which suffered barnacle infestation, Avicennia survived much better than Rhizophora, however the average growth in height in these sites was seriously affected. In general, height growth across various sites was about half that of Rhizophora. An exception was that in Shah Bundar sites, where growth averaged 1.2 m after 6 years. The two other species Ceriops tagal and Aegiceras corniculatum were planted in small quantities, only in 2.5% of the total planted areas. Ceriops survived well (about 83%) even in barnacle infested areas, but the height growth was limited. This does not come as a surprise since this species is bushy one. Barnacles affected Aegiceras and average survival was about 70% but the height growth was also not appreciable. In almost all sites where the project established new vegetation, natural regeneration of Avicennia (colonisation) took place, probably because these sites were protected from grazing animals. Planting sites which are located near JAT villages are generally not liked by the villagers, because these are the areas which were previously used for grazing their buffaloes and camels. However, so far the project has been able to protect these sites effectively with "grudging consent" of the Jats and locally recruited watchmen. The follow on project will first of all have to ensure the sustainability of the already established planting sites. Several sites may be used to harvest grasses when required by the nearby communities. Limited harvesting of Avicennia leaves for fodder may take place in the oldest established sites in the Kharochan area, while a limited quantity of fuel-wood may be collected from thinning of densely planted Rhizophora stands in Shah Bundar and Kharochan. Grazing of buffaloes and camels should not take place in any of the sites during the next five years. To ensure the local community’s collaboration for controlled use of the planting sites, management agreements should be discussed with the help of Jat community leaders. The project will also keep on employing locally recruited watchmen to enforce the controlled use of the sites. The proposed follow on project will be based on the experiences of the RRIDM project. Priority will be given to establishing vegetation in the best possible sites to avoid failures. It will make an inventory of the whole Indus delta to determine Class 1 planting sites, as defined by the project’s Mangrove consultant. Secondly, the project will compare the already completed ecological micro site description with species performance data for these sites. The latter will help determine species suitability for specific site conditions. To establish mangrove vegetation, the follow on project will concentrate its efforts on natural regeneration (colonisation) in Class 1 sites, by protecting these from grazing animals. To assist this colonisation process, various structures may be tested to assist capturing the floating seeds and wildings. Class 1 sites, which are not suitable for natural regeneration, will be planted. Collaboration with local communities for maintenance and management of new sites is essential, particularly with the herders of buffaloes and camels. It can be sought with the help of community leaders through awareness raising, joint selection of planting sites and the development of collaborative management plans. The local inhabitants will be encouraged furthermore to collaborate through giving incentives, such as the employment of locally recruited labour and watchmen and purchase of seeds/ wildings collected by them. The project will also test the use of new incentives which may include the provision of cash, materials and equipment to meet the community needs in exchange for their commitment to provide assistance/ protection to encourage natural regeneration process to take place. To strengthen the project’s capability to deal with increased community collaboration /participation, a community/extension forest officer will be added to the project staff. Finally the project, through the offices of the Sindh Forest Department and the Government of Sindh will encourage the gradual reintroduction of a system of fees for grazing buffaloes and camels; and the introduction of a mangrove tax or levy for the fishing sector. Such fees and levies may be used to recuperate part or all of the cost of planting and rehabilitation activities in the Indus delta mangrove ecosystem.

Research work on Marine Biology:

Taking advantage of a small financial assistance from the RRIDM project the Marine Reference Collection and Resource Centre, University of Karachi in collaboration with the Coastal Forest Division, Forest Department, Sindh has given a big step to initiate research works on Marine Biological aspects with emphasis on Fisheries Oceanography, details are given in Ali et al (1999). An inventory of shell and finfishes found in catches (Mahmood et al. 1999) of fishermen in different area of the Indus delta mangrove ecosystem has been made which reveals presence of all the major groups of mangrove loving species reported elsewhere (Singh, 1996). Record of physicochemical parameters reveals a great variation especially for salinity in different areas of the delta, probably a manifestation of erratic discharges of sweet water during monsoon, e.g., as that recorded for Shah Bundar and Keti Bundar ranges (Fig. 4). Analysed net plankton, and nekton samples collected from catches of small meshed destructive fishing gears (Boola and Gujjee) found being operated throughout the coast of Sindh, indicate presence of egg, larvae, juveniles and adolescents of many economically important shell and finfishes (see photographs) to underline the importance of the Indus delta mangrove ecosystem as an ideal habitat of fishery and other resources.

REFERENCES

Ahmed, M. 1985. Marine Fisheries of Pakistan. Centre of Excellence in Marine Biology.

University of Karachi. Pakistan. 206pp.

Ali, Q.M., Mahmood, N. and Ghani, N. 1999. Preliminary study on shrimp and finfish

nursery ground in the Indus delta mangrove ecosystem. Final Report.Hoekstra, D.A. 1998. Outline Follow on project Indus Delta Mangrove rehabilitation and

Replanting project. Sub–project RRIDM (world Bank/GoS funded). 57pp.Hoekstra, D.A., Mahmood, N., Shah,G.R., Shah, W.A. Domki, M.A. and Ali, Q.M. 1997.

Diagnostic Study - Indus delta Mangrove ecosystem. Main sub system characteristics, problems, potentials, proposed interventions and pilot sites. Sub-project RRIDM (World Bank/GoS funded). 76pp.

IUCN 1987 Socio-economic and Public health survey, 1987. 40pp.IUCN 1992 Natural resource use survey, Korangi / Phitti creek, 1992. 33pp.Karim, A. 1997. Rehabilitation and replanting of Indus delta mangroves. First

Assignment Report. DHV Consultants. 66 pp.Krishanmurthy, K and Jeyaseelan, M.J.P. 1984 Human impact on the Pichawaram

mangrove ecosystem. A case study from southern India. Proc. Asia. Symp.

Mangr. Env. – Res. & Manag. 624-632.MacNae, W. 1974 Mangrove forests and fisheries. Indian Ocean Programme. Pub. No

34. Indian Ocean Fishery Commission, Rome. 35 pp.Mahmood, N. 1995 On fishery significance of the mangroves of Bangladesh.

In,Mahmood, N. (Ed.)., Proceedings, Workshop on coastal Aquaculture and

Environmental Management, Cox’s Bazar Bangladesh. IMS. University of

Chittagong/ UNESCO. pp. 26-34.Mahmood, N. 1997 Indus delta mangrove ecosystem: Fishery aspect problems, potentials

and proposed. interventions. First Assignment Report. Sub-project RRIDM

(World Bank/GoS funded). 48pp.Mahmood, N., Ali, Q.M. and Vistro, N. 1999. Economically important fishery resources

of the Indus Delta Mangrove ecosystem. Sub-project RRIDM (World Bank/GoS

funded).65 pp.Martosubroto, P. and Naamin, N. 1997 Relationship between tidal forest Mangroves and

commercial shrimp production in Indonesia. Mar. Res. Indonesia. 18: 81-86.Mirza, F.B. 1986. Epibenthic fauna of Indus deltaic region and adjoining creeks. National

Seminar on Fisheries Policy and planning. 21-23 Sept. 1986. Karachi. Abst.1p.Saifullah, S.M. 1992 Future prospects of mangroves in development of Makran coast. In:

Proc. Nat. Conf. Problems and Resources of Makran coast and plan of action for

its development. Sept. 1991. Quetta. pp. 63-68.Shah, G.R. 1998 Sociological report: Indus delta mangrove ecosystem. Coastal Forest

Division – Sindh Forest Department- DHV- Consultants. 90 pp.Shirkat Gah 1997 Socio-economic and natural resource use survey 1997, in Ibrahim

Hydari and Rehri (update of information to Natural Resource use survey in

1992).26 pp.Singh, H.R. 1996 The Ecological Role of Mangroves. Nature: Malaysiana. 21(2): 59-63.Turner, R.E. 1977 Intertidal vegetation and commercial yields of penaeid shrimp. Trans.

Amer. Fisheries Soc. 106(5): 411-416.