Mangrove swamps supply various goods and provide invaluable ecological services, especially as critical habitats for fish breeding. These functions are discussed in the context of rural livelihoods of coastal dwellers in the Niger Delta in particular, and the contribution to national economies in general. The decline in capture fisheries production in Nigeria is partly linked to massive mangrove loss in the Niger Delta. This provides basis for urgent evolution of effective mangrove conservation schemes in the Niger Delta and for focused research on the interaction between the delta mangroves and inland/coastal fish recruitment and production dynamics

Erondu, E.S.

Hart, A.I.

Zabbey, N.

Aquatic Commons

  
FSN-CA 0002 
FUNCTIONAL ROLES OF MANGROVES OF THE NIGER DELTA TO THE 
COASTAL COMMUNITIES AND NATIONAL ECONOMY 
 
1
ZABBEY, N., 
2
A. I. HART and 
1
E. S. ERONDU 
 
1 Department of Animal Science and Fisheries, Faculty of Agriculture, University of Port Harcourt, Rivers State. 
2 Department of Animal and Environmental Biology, Faculty of Science, University of Port Harcourt 
 
Copyright 2010, Fisheries Society of Nigeria. 
 
This paper was prepared for presentation at the 25th Annual International 
Conference and Exhibition in Administrative Staff College of Nigeria 
(ASCON), Topo-Badagry, Lagos, Nigeria, 25th – 29th October, 2010. 
  
This paper was selected for presentation by an FISON Program Committee 
following review of information contained in an abstract submitted by the 
author(s). Contents of the paper, as presented, have not been reviewed by 
the Fisheries Society of Nigeria and are subject to correction by the author(s). 
The material, as presented, does not necessarily reflect any position of the 
Fisheries Society of Nigeria, its officers, or members. Papers presented at 
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acknowledgement of where and by whom the paper was presented. Write 
Librarian, Fisheries Society of Nigeria (FISON), P. O. Box 2607 Apapa, 
Lagos. 
 
ABSTRACT 
Mangrove swamps supply various goods 
and provide invaluable ecological 
services, especially as critical habitats for 
fish breeding. These functions are 
discussed in the context of rural 
livelihoods of coastal dwellers in the Niger 
Delta in particular, and the contribution to 
national economies in general. The decline 
in capture fisheries production in Nigeria 
is partly linked to massive mangrove loss 
in the Niger Delta. This provides basis for 
urgent evolution of effective mangrove 
conservation schemes in the Niger Delta 
and for focused research on the 
interaction between the delta mangroves 
and inland/coastal fish recruitment and 
production dynamics. 
 
INTRODUCTION 
Oftentimes, our familiarity with 
mangroves makes us not to reflect on their 
importance, in terms of rural livelihood 
support, food supply and coastal 
protection. No doubts, the undervaluation, 
or simply non recognition of the goods and 
services that mangroves provide are the 
reasons why mangrove habitats are 
considered wasteland or are sites of choice 
for conversion to one form of development 
or the other.  
Mangroves, in terms of contribution to 
rural development, are to coastal 
communities what taxes are to national 
governments. Mangroves provide various 
ecological goods and services directly for 
humankind, and indirectly through the 
supporting roles mangrove forests play in 
maintaining other productive systems in 
the seascape. The estimated economic 
value of mangrove forests to local 
community is in the range of $27,264 - 
$35,921 per hectare (Sathirathai and 
Barbiar, 2001). This estimate includes the 
value of direct use of wood and other 
resources collected from mangroves as 
well as additional external benefits in 
terms of off-shore fishery linkages and 
coastline protection. 
 Recently, Federal Department of Fisheries 
(FDF, 2007) gave reasons for decrease in 
fish production in Nigeria but mangrove 
degradation in the Niger Delta was 
conspicuously omitted. This paper 
highlights some of the ecosystem goods 
and ecological services that mangroves 
provide for the delta littoral and hinterland 
communities in Nigeria. It identifies 
consistent and unprecedented shrinkage of 
Nigeria’s mangroves as an insidious factor 
accountable for decline in fish catch rates 
in the country, and by extension, in the 
entire Gulf of Guinea. 
 
Nigeria’s Mangrove belt 
Nigeria’s mangrove, in terms of area 
covered, is the largest in Africa and the 
fourth largest in the world; the largest 
being Indonesia>Brazil>Australia>Nigeria 
(Nandy and Mitra, 2004). According to 
Spalding et al. (1997), the mangrove area 
of Nigeria is estimated at 10,515km
2
; the 
estimate is based on earlier surveys and 
120 Zabbey, N., Hart A. I. & Erondu E. S. FISON EKO 2010 
ISSN: 1117-3149 PROCEEDINGS OF FISHERIES SOCIETY OF NIGERIA (FISON) ASCON, BADAGRY 25th-29th OCTOBER 2010  FSN-CA 0002 
does not reflect current status (Zabbey, 
2008). 
The deforestation rate of tropical rainforest 
forest (not wetlands forest) in Nigeria is 
approximately 3.5% annually, translating 
to a loss of 350,000 – 400,000 ha of forest 
land per year (Ladipo, 2010). Similar 
estimate does not exist for mangrove loss 
in Nigeria. However, in our opinion, areal 
loss of mangrove is much higher than the 
above estimate due to the frequent and 
extensive losses caused by oil spillages 
and unhindered spread of nypa palm in the 
Niger Delta. Other causes of mangrove 
loss in Nigeria include overexploitation for 
fuel wood, conversion to other forms of 
development, dredging and industrial 
discharges. 
 
Mangrove Resources 
Mangroves provide local communities 
with several goods free of charge. These 
include fish, shrimp, crabs, firewood, 
poles, honey, boat building material, 
furniture, traditional medicine, etc. 
Mangrove bark is used for colouring of 
cloth and nets, net preservation and glue 
production. Mangrove stem and branches 
are used as handles for traditional fan, net 
mending stick, handles for axes and 
spades, drum sticks and carving of drums 
(gongs). At least, 24 mangrove goods have 
been identified (Ronnback et al., 2007). 
 
Ecological Services 
Ronnback et al. (2007) listed nine services, 
grouped under three broad functions 
namely: regulatory, reproductive and 
cultural functions. Mangroves are the first 
lines of defence of littoral communities, 
protecting them against coastal storms, 
erosion and floods. A case in point, and 
indeed more dramatic scenario, whereby 
mangroves protect coastal dwellers is that 
of the Indian Ocean tsunami of December 
2004. The tsunami storms travelled at 
more than 600 km/h and struck coastlines 
as a wave of more than 15m. It is actually 
difficult to quantify the protective effects 
of mangroves, because coasts vary in 
topography and in most areas little precise 
information was recorded of the magnitude 
of the tsunami. However, studies in India 
concluded that mangroves saved lives and 
mitigated damage (Hogarth, 2007). 
According to Danielsen et al. (2005), 
villages on the coast were completely 
destroyed, whereas those behind the 
mangrove suffered no destruction even 
though the waves damaged areas 
unshielded by vegetation north and south 
of these villages.  Other reports have 
shown how mangroves counteract tropical 
storms and their capacity to stabilize 
shoreline substrate thereby protecting it 
from erosion (Mazda et al., 2006) 
Translating the protective value of 
mangroves into monetary value will 
deepen our appreciation. Some areas in the 
Upper Gulf of Thailand coastlines have 
been eroding at 28m/year between 1969 
and 1987 (Akornkoae et al., 1993), owing 
to a large extent to massive mangrove 
losses. There are no similar estimates of 
mangrove loss due to riparian erosion in 
Nigeria. The replacement cost of building 
hard protective structures to replace the 
coastal protection service once generated 
by mangroves can be significant. In 
Peninsular Malaysia, Chan et al. (1993) 
estimated this cost at US$ 3 million/km 
coastline. Erecting these single-service 
artificial seawalls with limited lifetime is 
one thing, maintaining them is another 
issue. 
Many riverbank communities in the Niger 
Delta are facing the threat of being washed 
away by shoreline erosion. Hundreds of 
millions of naira are purportedly invested 
in the construction of protective shoreline 
embankment to save some of the worst 
affected communities from becoming 
extinct. Without going into the 
performance evaluation of the shore 
protection projects in the Niger Delta, the 
instructive point of note is the huge sums 
of money assigned to these projects and 
the fact that mangroves hitherto protected 
those communities and are protecting other 
littoral communities free of charge! 
Mangroves maintain good water quality, 
that is, by preventing fluctuations in 
121 Functional Roles Of Mangroves Of The Niger Delta To The Coastal Communities And National Economy FISON EKO 2010 
ISSN: 1117-3149 PROCEEDINGS OF FISHERIES SOCIETY OF NIGERIA (FISON) ASCON, BADAGRY 25th-29th OCTOBER 2010  FSN-CA 0002 
salinity and turbidity, reduces 
concentrations of pollutants, and control 
nutrient levels in coastal waters 
(Kuhlmann, 1988; Kitheka, 1997).      
Mangroves are important breeding and 
nursery sites for many commercially 
important shrimp, crab and fish. While 
some of these species are permanent 
residents (such as oysters, dog whelk, etc), 
some are temporary residents –associated 
with mangroves during at least one stage 
in their life history. Juvenile fish and 
shrimp have been found to move 
substantial distances into mangrove forest 
habitat at high tide, where they gain 
protection from predation by larger fish, 
which remain in or near mangrove water 
ways. By this, recruits are sufficiently 
available to replenish individuals removed 
from the stocks, either through fishing or 
due to natural mortalities (Hogarth, 2007).  
Beside fishes that utilize mangrove forests 
as transitory habitats, several species of 
molluscs that are largely sessile in nature 
constitute an important in-situ fishery. 
This is the case of our highly relished 
oysters, periwinkle and dog whelk (that 
feature prominently in native soup). 
There is dearth or absence of research data 
on the contribution of mangroves to 
specific commercial fish stocks in Nigeria. 
However, it has been estimated that 60% 
of commercial fishes in the Gulf of Guinea 
breed in the mangroves of the Niger Delta 
(Bassey, 1999). The above percent are 
conservative if Nigerian fish stocks are 
considered separately from other maritime 
states in the Gulf of Guinea.  
 
 
 
Is mangrove loss indicted for declining 
capture fisheries production in Nigeria? 
Though debate around the role of 
mangrove forest as nursery habitat 
continues (Sheridan and Hays, 2003; 
Manson et al., 2005), increasing number of 
studies have coupled wild fish and 
invertebrates production to mangrove 
habitat nursery and protective functions 
(Lewis et al, 1985; Wolansky and Boto, 
1990; Thomas and Connolly, 2001; Crona 
and Ronnback, 2007). It is estimated that 
each square kilometre of mangroves can 
support a fishery production of 90 – 280 
tonnes annually (Ronnback, 1999). Thus, 
mangroves are nature’s own aquaculture 
system, having multi-functional 
advantages over single-service artificial 
culture systems (Moberg and Ronnback, 
2003).  In Nigeria, field based data 
pertaining to the contribution of 
mangroves to specific fisheries production 
are lacking. But based on surrogate 
findings around the globe, we presume that 
the unprecedented rates of mangrove 
degradation and loss in the Niger Delta is 
one of the  major, but neglected 
contributors to declining wild fisheries in 
Nigeria. Mangrove fish preference and 
maintenance function should, therefore, 
form a significant research focus of 
statutory institutes and Fisheries Society of 
Nigeria (FISON) members. This will 
enable us to understand and quantify the 
role Niger Delta mangrove plays in coastal 
fish recruitment, and provide scientific 
basis for the evolution of informed 
mangrove conservation strategy. 
Mangrove restoration and establishment of 
mangrove protected areas are 
recommended. This will ultimately protect 
rural and national fish-based economies.  
 
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Functional roles of mangroves of the Niger Delta to the coastal communities and national economy

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