Responsable WP1
DemerstEm, DEMERsal ecosySTEMsOur project is part of the PESCAO program, and aims to improve scientific advice production on shared demersal stock in West Africa (Ecowas Area) .
The EU DEMERSTEM project started in March 2019. We are now heading towards our third year of the project whilst undergoing the turbulence of the COVID 19 Pandemic.
Despite the pandemic, we are moving forward even if at a slower pace. This newsletter will remind partners that we are doing our best in spite of the situation.
In order to feed these methods, we collect information for more than one year. Data is being collected using mainly commercial landings (artisanal and industrial one). More precisely, each of the partners has to measure, weigh, take a picture, determine sex, check for parasite presence and extract muscle tissue for genetic analysis … following an agreed protocol (establish during DEMERSTEM working group 2, update during WG 3) on more than one thousand fish.
Then data is centralized on a common platform using either an Android phone app or classical excel files. Agrocampus Ouest was in charge of this data centralization. Nowadays, information about more than 18 000 fish from 6 species are available in this common database. More than 3 300 pictures are also available for morphometry analysis.
For this activity, we also had the chance to collaborate with our Gambian colleagues through agreement with CRODT. This collaboration should go forward during stock assessment working groups.
Trophic interaction (WP4) : During 2019, Priscilla Licandro (SZN), in collaboration with IMROP and CNSHB included plankton and jellyfish data collection within national scientific surveys. These samples will be analysed by Priscilla at SZN in order to complete trophic analysis on both ecosystems.
During this first year, we have met together in March during the kick of meeting in Saly (Senegal). During this meeting, we have detailed planned activities within our project. We have shared this overview with regional fisheries commissions (SRFC and FCWC) and regional institutions (ECOWAS and UEMOA). We also met representatives of other selected project under the PESCAO Call of tender: GREPPAO leaded by Pierre Failler from the University of Portsmouth and FAO colleagues.
Within the Work package 3 of DEMERSTEM, a small-scale fisheries monitoring system using GPS was implemented in Guinea and Bissau Guinea. . 20 GPS have been deployed on Canoe landing in Kamsar and Katcheck port in Guinea and Cacine in Bissau Guinea. A data collection protocol was also implemented to collect landings data on GPS monitored pirogues. Mohamed Soumah, from CNSHB, has leaded this activity with trainings in both countries (for CNSHB and CIPA colleagues in charge of the survey). Mohamed carried out a second mission in Bissau to control and adapt the protocol.
In April, Jérôme Guitton was in Ghana for the FAO/PESCAO kick off meeting to present DEMESTEM acivities and to try promoting synergies between DEMERSTEM and FAO project. (Ghana 24-27th April 2019)
Modou Thiaw carried out a mission to Guinea in order to learn about GPS data collection implemented by Mohamed Soumah. CRODT wanted to implement a similar protocol for Kayar smal scales fisheries. Mohamed carried a mission in France (22th of June to 6th of July) to work mainly with Jerome Guitton to develop a suitable database for GPS and survey data collection. We also worked with Marie Pierre Etienne (Agrocampus Ouest) and Nicolas Bez (IRD) on data analysis. GPS trajectories are analysed to calculate and spatialized effort of pirogues. Following this mission an onboard fishing activities monitoring was carried out in order to feed learnings algorithms.
Within the work package 4 on Ecosystem Approach, and during regular scientific trawl survey, CNSHB carried out a specific jellyfish and plankton survey.
For the stock identification activity (WP1) a working group was organized to share, train and promote a biological data collection (From 27th to 30th of August - Nouakchott) . This workshop was leaded by our IEO partners (Thanks to Eva Garcia Isarch and José F. Gonzalez Jiménez) and co-organized with IMROP (Thanks to Beyah). This meeting was the starting point for the biological data collection that will be carried out during one year. The main objective is to collect data for a better spatial definition of stocks selected within the DEMERSTEM project.
We initially planned 4 scientists for the long training period in Europe within the DEMERSTEM framework. Finally, 5 Phd candidates were selected and were invited to come to France. They arrived in September for a 3.5-month period. They shared their time between courses of the Fisheries and Aquaculture Master of Agrocampus and the main core of their case study subject. One main objective of these periods is to create synergies between DEMERSTEM partners and interaction with their AGrocampus Co-supervisor (Didier Gascuel for stock assessment case studies and Olivier Le Pape for sensitive habitat subjects). Ato Ekuban from Ghana (Fisheries division) has also been with us for two months, mainly to learn French but also to interact with Ivory Coast scientist on the sensitive habitats assessment of Ghana/Ivory Coast Area.
Priscilla Licandro from SZN was on board of the Mauritanian Scientific Vessel (El Awam). Her objective was to implement jellyfish and plankton data collection within the Ecosystem work package (WP4).
During DemerstEm project, we plan to set up a Regional Database of Scientific trawling survey. We have been inspired by the PRESH project developped by
UEMOA. Data availability is often an issue for producing a shared input for stocks assessment models. This regional Database, and the tools we can develop to easily access and use it,
will improve the use of these costly data in the scientific advice process. Depending on the data policy, we will be able to plug the database to the stock assessment models.
We propose to encourage this data gathering developping ad on services as :
We will focus on Stock identity of Case study selected species. We will use complementary approach and methodologies :
Once the data are collected and the stock identity defined, we can start the stock assessment process.
Several methods will be applied regarding the availability of data. We first plan to generalized methods used by Meissa et al 2017.
Then, partners will evaluate alternatives of complementary apprpriate methods to the life history traits of the species (ie : ad hoc methods for short living species) or to the data limited status of the stocks
The renewal of exploited marines ressources is a result of a good level of spawning biomass but also a result of the quality of habitats from wich stocks are highly dependent during part of their life
cycle. Population dynamic of marine living species is very specific comparing to terrestrial species as it's a mix bettween high variabliity of fecondity, survival and high dependency to environnmental conditions.
High survival variability makes this ressources highly dependent of the quality of succesives habitats used during their life cycle.
In particular, renewal of fish stocks is highly dependant of nurseries habitat, located in coastal area for a large proportion of exploited ressources.
During breeding season, adults concentration on spawing ground is high. However these spawing grounds is not especially located in coastal area.
Indeed, fisheries management does not have to only focus on fishing effort and catches control but should also take care of sensitives areas.
Coastal area degradation due to fisheries but also due to other human activities can explain decrease of fish biomass.
Sensitive area reduction or decrease of their quality can affect recruitment and fish population size. However our needed knowledge to 1) identify sensitive area necessary to renewal fish population 2) to quantify
benefit of area protection against human activities is really yet poor, especially in west african countries.
It is why the main objective of this wp is to collect data and available information that can help us to identify nurseries or spawing grounds and to use these data as input of models to produce quantitatives maps of sensitive habitats.
List of planned actions :
One issue in the stock assessment process is often to obtain data on small scale fisheries, especially in coastal area. This is a challenge for us to help data collection on fisheries that rely to the sensistive habitat defined in WP2.
We suggest to use GPS logger ant pathway analysis to obtain more precise view of effort due to small scale fisheries in sensisitive habitat.
If data are available we could make a similiar analysis using VMS data for industrial fisheries and maybe for spawing area .
DemerstEm project aims to improve monospecific assessment, howerever, fisheries scientists are aware of this approach limitations. Taking into account the global ecosystem, with trophic interactions is needed;
That will be done studying trophic interactions between groups of prey and predators as a description of the Ecosystem..
Moreover Global change is also impacting west african marine ecosystem with some modification in the trophic chain.These altered trophic interaction will modify stocks productivity.
Recent changes seems to be good for jellyfish profileration that will impact negativly demersal species as they are predators for fish eggs and larvaes and competitors for juveniles food.
We suggets 4 approachs to take into account the complexity of the Demersal Ecosystem to improve our knowledge on impact due to coastal Ecosystems changes on the variability of exploited stock biomass.
More than 30 scientists of these instututions are involved in DemerstEm
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