Download presentation La Paz_Senegal

Modélisation spatiale de
l’écosystème
Sénégalogambien
By
Birane SAMB
Fishery Biologist
CRODT, Dakar, Sénégal
[email protected]
Senegal is located in North West
Africa
Atlantic Ocean
Map of Senegal
MAP of AFRICA
Importance of fisheries sector in
Senegal
•
11 500 000 habitants with more than
50% of population in coastal zone
• 700 km coastline, with continental shelf
area of 24 000 km2
• First sector of export
Importance of fisheries sector in
Senegal (suite)
• Takes an important place in the supply of
animal proteins
• 600 000 indirect employments
• 15% of the working population
• Annual consumption 26kg/year/ha where in
Africa the mean consumption is 8.2 /year/ha
Fisheries
– The artisanal fishery consists of motorised
canoes using a variety of gear. Essential
catches are done by artisanal fisheries
– The industrial fishery is undertaken by
trawlers or purse seiners, some of which are
foreign vessels operating under commercial
agreements.
Marine Resources
• Marine resources are characterized by their diversity
• (i) Pelagic resources consisting of clupeids engraulids,
carangids, scombrids, tuna and sharks. These species
constitute up to 75% of the stocks. (ii) Demersal
resources which have a higher economic value include
crustaceans (shrimps, lobsters, and crabs), molluscs,
cephalopods as well as bony fish (serranids, lutjanids,
sciaenids, mullets, etc.), rays, and sharks. (iii) Coastal
and estuarine resources, comprising bivalves and fish
(cichlids, mullets, etc).
Objectives
Use Ecosim and Ecospace to Study the
impacts of fisheries on the ecosystem
Definition groupes
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Oiseaux marins
Mammifères marins
Pélagiques du large:
Sharks
Rays
Céphalopodes: poulpes, seiches, calmars et autres
Merous
Pagre
Otolithe
Others demersals
Sardinelle ronde
Sardinelle plate
Others pélagiques
Zooplancton
Meiobenthos
Macrobenthos
Producteurs benthiques
Phytoplancton
Rejets
Détritus
Habitat and assign habitat
Location of MPA
• 2 at the north
• 2 at the south
Scenario modelling
•
•
•
•
Les scénarios suivants sur 10 ans ont été testés :
-hausse d’effort de la pêche artisanale et maintien du
niveau actuel de la pêche industrielle (scénario 1)
-baisse d’effort de la pêche artisanale et maintien du
niveau actuel de la pêche industrielle (scénario 2)
-hausse d’effort de la pêche industrielle et maintien du
niveau actuel de la pêche artisanale (scénario 3)
-baisse d’effort de la pêche industrielle et maintien du
niveau actuel de la pêche artisanale (scénario 4)
Result of scenario 1
PA increase
Result of scenario 2
PA decrease
Preliminary conclusion
• Two groups constitute the main targets for
fisheries. Pelagics fish stocks and demersal
species.
• Actual level of stocks are overexploitation of
demersal stock like mérou, pagre et otolithe.
Small pelagic fish like Sardinella are less
exploited.
• Model indicate clearly that increase of artisanal
fishing effort continue to the overexploitation. In
contrario all measures leading to decrease the
pressure of artisanal gear will help to restore the
abundance of species.
Next step
Make scénario
about variation of size of MPA
location of MPA