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Effectiveness of Marine Protected Areas as a tool for restoring
marine resources: Estuarine West African experience
Oumar Sadioa, Jean-Marc Ecoutinb, Luis Tito de Moraisc, Monique Simierd, Jean Raffrayc and Raymond Laëe
a : IRD, CRODT/LEMAR (UBO/CNRS/IRD/Ifremer), BP 1386, Dakar, Sénégal. b : IRD, LEMAR (UBO/CNRS/IRD/Ifremer), Avenue Jean Monnet, BP 171,
34203 Sète Cedex, France. c : IRD, LEMAR (UBO/CNRS/IRD/Ifremer), BP 70, 29280 Plouzané, France. d : IRD, EME (UM2/IRD/Ifremer), Avenue Jean
Monnet, BP 171, 34203 Sète Cedex, France. e : IRD, LEMAR (UBO/CNRS/IRD/Ifremer), Bd Sidi Abderrahman Ain Diab, Casablanca, Maroc
Introduction
Faced with the growing threat of alteration and overfishing of marine resources by human and climatic pressures steadily increasing, the establishment of
marine protected areas (MPAs) appears to be a response to the conservation or restoration of biodiversity (Ecoutin et al. 2014). Bamboung MPA was created in
2004 by the Senegalese government (Breuil 2011). This MPA is protected from all fishing activities. The objective of this study is to evaluate the effectiveness
of Bamboung MPA as a tool for restoring marine resources by comparing it to Sangako bolon which is an area opened to all forms of fishing activities.
Materials and methods
The two areas are in the Sine Saloum estuary in Senegal (West African
tropical zone) (Fig. 1). The temporal sampling plan took into account the
existence of three major hydro-climatic seasons across the Sine Saloum
(Diouf 1996; Simier et al. 2004). Fish sampling was performed using a
purse seine net with the same methodology in the two areas. Three
surveys were conducted annually from 2008 to 2011. Fish were
identified by species and then counted and weighed by species to the
nearest gram for each seine haul. A subsample of up to 30 individuals per
species per haul was measured to the nearest mm. Observed species were
classified into bio-ecological categories end by trophic group. The
bioecological indicators and the physico-chemical parameters measured
were compared between the two areas.
The physico-chemical parameters did not differ between the two areas.
Between 2008 to 2011, 54 species belonging to 28 families were
identified in the AMP against 47 species belonging to 23 families in the
fished area. Median abundance and richness observed are higher in the
unprotected area while the estimated biomass, the trophic level, the
average size and maximum size are in favor of AMP (Tab. 1). These
results corroborate those of many authors (Halpern 2003, Lester et al.
2009). The size spectra is different between the two areas (Fig. 2).
According to the analysis of ecological guild, species fulfilling all their
life cycle in the estuary are less present in the MPA (Fig. 3). The trophic
composition analysis of the settlement of MPA highlights a major role
given to the predatory and predatory especially high-level component
(Fig. 4).
Figure 1: Location and map of the delta of Sine Saloum (Senegal). Location of the
Bamboung AMP and the Sangako bolon with position of their sampling area.
Log(Effective)
Results
Mean
Coefficient
variation (%)
Median
Minimum
Maximum
BBG
60
676
381
35
0
19127
SNK
72
310
209
100
0
3929
BBG
60
24730
278
7176
0
387410
SNK
72
10589
133
6059
0
70415
BBG
60
7
55
6
1
17
SNK
72
9
35
9
0
19
Trophic
Level
BBG
59
3.1
18
3.2
3
4
SNK
71
2.7
16
2.8
2
4
Mean size
(mm)
BBG
59
178
43
154
82
362
SNK
71
145
22
145
96
252
Maximum size
(mm)
BBG
59
428
50
390
82
1055
SNK
71
321
32
285
113
635
Abundance
Biomass
(g)
Richness
Discussion et conclusion
Both areas have similar water body. Then, the differences are due to
the protection effect of Bamboung Bolon. Total species richness is
higher in the MPA than in the fished area. From 2008 to 2011, the MPA
has a positive effect on biomass, trophic level and size, and a negative
effect on the abundance and richness. Estuarine affinity species lose
their importance in the MPA while marine affinity species strengthen
their central role in the MPA. The results clearly reflect the attraction
effect of an MPA and therefore we can confirm that AMP is an
effective tool for restoring marine biodiversity.
20
30
40
50
60
70
80
90
100 110
120
Figure 2: Size spectra of the fish assemblage of Bamboung MPA (blue line) and
Sangako bolon (red line) from 2008 to 2011.
BBG
1
Log(Effective)
Number of
observations
10
SNK
Size (cm)
SNK
0.8
0.6
0.4
0.2
0
0
5
10
15
20
25
Size (cm)
30
35
40
Figure 3: Size spectra of strict estuarine species, 2008 to 2011. BBG = Bamboung
MPA (blue line) and SNK = Sangako bolon (red line).
BBG
Log(Effective)
Area
2.5
2
1.5
1
0.5
0
0
Tableau 1: Comparison of bio-ecological indicators by catch per unit.
BBG, Bamboung MPA and SNK, Sangako bolon, from 2008 to 2011.
Bioecological
indicators
BBG
SNK
0.1
0.08
0.06
0.04
0.02
0
0
20
40
Size (cm)
60
80
100
Figure 4: Size spectra of piscivorous, 2008 to 2011. BBG = Bamboung MPA (blue
line) and SNK = Sangako bolon (red line).
Acknowledgments
The results presented here are from the multidisciplinary program-related projects: Narou Heuleuk (FFEM / AFD / NGO Oceanium / IRD), AMPhore (ANR
Biodiversity), CEPIA (AFD / CSRP / IUCN / IRD). The authors want to thank the fishermen and their team leader Mbaye Mbengue and the crew from
research vessel Diassanga and its captain F. Sanseo. Without their help, these results could not have been obtained.