Didier Jouffre

• Senior Researcher at Institute of Research for Development

Large‐scale biodiversity assessments and conservation applications require integrated and up‐to‐date datasets across regions. In the oceans, monitoring is fragmented, which affects knowledge exchange and usage. Among existing monitoring programs, scientific bottom‐trawl surveys (SBTS) are long‐term, rich, and well‐maintained data sources at the sca...

FISHGLOB brings together experts in, and users of, fish monitoring data to support biodiversity research and conservation across oceans.

Trichiurus lepturus is a benthopelagic species of socio-economic importance in Senegal. Despite its intensive exploitation, there is a lack of studies on its life traits in West African waters, particularly in Senegal. This study aims to determine the biological parameters of this species in the northern coastal zone of Senegal. Samples were collec...

Marine biota are redistributing at a rapid pace in response to climate change and shifting seascapes. While changes in fish populations and community structure threaten the sustainability of fisheries, our capacity to adapt by tracking and projecting marine species remains a challenge due to data discontinuities in biological observations, lack of...

Marine biota is redistributing at a rapid pace in response to climate change and shifting seascapes. While changes in fish populations and community structure threaten the sustainability of fisheries, our capacity to adapt by tracking and projecting marine species remains a challenge due to data discontinuities in biological observations, lack of d...

For the first time in Senegal, assessments based on both stochastic and deterministic production models were used to draw a global diagnosis of the fishing impact on coastal demersal stocks. Based one national fisheries databases and scientific trawl surveys data: (i) trends in landings since 1971 were examined, (ii) abundance indices of 10 stocks...

The reproduction of Arius latiscutatus (Günther, 1864) was studied both inside and outside of the Bamboung marine protected area (MPA) (Saloum Delta) in Senegal, from individuals collected monthly from April 2015 to March 2016. The reproductive parameters were quantified from the macroscopic examination of the gonads and from the counting and measu...

In Guinea, among the small pelagics exploited, ethmalose is the subject of an intense maritime artisanal fishing and constitutes one of the most important species from an economic point of view. The present study aims to highlight the socio-economic importance of the fishing of ethmalose and to analyze the spatio-temporal distribution of its abunda...

An inventory of significant ecological events in West African coastal marine ecosystems over the last decades has been conducted by combining three approaches: a document review, a survey of fishermen and an analysis of fishery statistics. This method allowed to identify an initial series of events that took place over the period 1970 to 2014, main...

Early life stages of dominant West African pelagic fishes, most of which are commercially important, are rarely studied especially in Senegalese and Mauritanian coastal waters. The aim of the present study is to examine the horizontal distribution of pelagic fish eggs of Atlantic sardine (Sardina pilchardus), anchovy (Engraulis encrasicolus), sardi...

Early life stages of dominant West African pelagic fishes, most of which are commercially important, are rarely studied especially in Senegalese and Mauritanian coastal waters. The aim of the present study was to examine the horizontal distribution of pelagic fish eggs of European sardine (Sardina pilchardus), anchovy (Engraulis encrasicolus), roun...

This study aims to determine whether Bamboung Marine Protected Area (BMPA) in the Saloum Delta, Senegal, had any effect on reproductive traits of the rough-head sea catfish, Arius latiscutatus (Günther, 1864). The monthly variations in condition factor were similar inside and outside the BMPA. The lowest values of K were 0.75 in both sites and the...

We present a mathematical model of two competing marine species that are harvested. We consider three models according to different levels of complexity, without and with species refuge and density-independent and density-dependent species movement between fishing area and refuge. We particularly study the effects of the fishing pressure on the out...

Fisheries have had major negative impacts on marine ecosystems, and effective fisheries management and governance are needed to achieve sustainable fisheries, biodiversity conservation goals and thus good ecosystem status. To date, the IndiS-eas programme (Indicators for the Seas) has focussed on assessing the ecological impacts of fishing at the e...

In a context of growing fishing pressures and recommendations for an ecosystem approach to fisheries, there is a need to monitor changes in fish communities over time. In this study, we analysed data from scientific trawl surveys carried out on the continental shelf off Guinea between 1985 and 2012. We performed factorial analyses and calculated bi...

IndiSeas (“Indicators for the Seas”) is a collaborative international working group that was established in 2005 to evaluate the status of exploited marine ecosystems using a suite of indicators in a comparative framework. An initial shortlist of seven ecological indicators was selected to quantify the effects of fishing on the broader ecosystem us...

Understanding how external pressures impact ecosystem structure and functioning is essential for ecosystem based approaches to fisheries management. We quantified the relative effects of fisheries exploitation and environmental conditions on ecological indicators derived from two different data sources, fisheries catch data (catch-based) and fisher...

Fisheries provide critical provisioning services, especially given increasing human population. Understanding where marine communities are declining provides an indication of ecosystems of concern and highlights potential conflicts between seafood provisioning from wild fisheries and other ecosystem services. Here we use the nonparametric statistic...

Short-lived species are extremely dependent on the seasonal and interannual variability of environmental conditions, and determining their stock status is often difficult. This study investigates the effects of environmental variability and fishing pressure on the stock of octopus Octopus vulgaris in Senegalese waters over a 10-year period from 199...

Shin, Y-J., Shannon, L. J., Bundy, A., Coll, M., Aydin, K., Bez, N., Blanchard, J. L., Borges, M. F., Diallo, I., Diaz, E., Heymans, J. J., Hill, L., Johannesen, E., Jouffre, D., Kifani, S., Labrosse, P., Link, J. S., Mackinson, S., Masski, H., Möllmann, C., Neira, S., Ojaveer, H., ould Mohammed Abdallahi, K., Perry, I., Thiao, D., Yemane, D., and...

J. 2010. Comparing data-based indicators across upwelling and comparable systems for communicating ecosystem states and trends. – ICES Journal of Marine Science, 67: 807– 832. A suite of ecological indicators was selected for communicating, in a comparable way, how fishing affects the state of several upwelling ecosystems and others in which small...

Within the IndiSeas WG, the evaluation of exploited marine ecosystems has several steps, from simple binary categorization of ecosystems to a more-complex attempt to rank them and to evaluate their status using decision-tree analyses. With the intention of communicating scientific knowledge to the public and stakeholders, focus is on evaluating and...

Coll, M., Shannon, L. J., Yemane, D., Link, J. S., Ojaveer, H., Neira, S., Jouffre, D., Labrosse, P., Heymans, J. J., Fulton, E. A., and Shin, Y-J. 2010. Ranking the ecological relative status of exploited marine ecosystems. – ICES Journal of Marine Science, 67: 769–786. A set of simple, data-based ecological indicators was used to rank exploited e...

Under the context of an ecosystem approach to fisheries (EAF), there is keen interest in providing insights into the evolution of exploited ecosystems using simple ecosystem indicators. Many nations have long-term scientific research surveys, originally driven by conventional approaches in fisheries assessment and management. The aim of this study...

Blanchard, J. L., Coll, M., Trenkel, V. M., Vergnon, R., Yemane, D., Jouffre, D., Link, J. S., and Shin, Y-J. 2010. Trend analysis of indicators: a comparison of recent changes in the status of marine ecosystems around the world. – ICES Journal of Marine Science, 67: 732–744. Time-series of ecological and exploitation indicators collected from 19 e...

In Senegal, two stocks of white shrimp (Penaeus notialis) are intensively exploited, one in the north and another in the south. We used surplus production models including environmental effects to analyse their changes in abundance over the past 10 years and to estimate their Maximum Sustainable Yield (MSY) and the related fishing effort (EMSY). Fi...

Cephalopod movement occurs during all phases of the life history, with the abundance and location of cephalopod populations strongly influenced by the prevalence and scale of their movements. Environmental parameters, such as sea temperature and oceanographic processes, have a large influence on movement at the various life cycle stages, particular...

L'état du stock du poulpe en Mauritanie a été évalué à plusieurs reprises par les modèles de production. En particulier, le groupe de travail COPACE 2004 (sous presse) et plus récemment le GT démersal IMROP-RIVO en janvier 2006 (Ould Mahmoud et al., 2006) ont permis d'évaluer l'état du stock de poulpe (Octopus vulgaris) et de la pêcherie à partir d...

The assemblages of demersal fish and associated species of the Mauritanian continental shelf are characterized on the basis of annual trawl surveys conducted during the period 1987–1999. Species composition is dominated by exploited species (Dentex spp., Pagellus bellottii, and Octopus vulgaris). Dominance curves (Abundance Biomass Comparison plots...

The dynamics of the Octopus vulgaris (Cuvier, 1797) population in Senegalese waters is modelled to evaluate the potential impact of combining temporal fishing closure and minimum size of capture on the production of this stock. The study is based on an analytical approach (cohort analysis and simulation of captures on a monthly basis) adapted to th...

Octopuses are generally characterised by rapid non-asymptotic growth, with high individual variability. However, in situ octopus growth is not well understood. The lack of an ageing method has resulted in the majority of our understanding of octopus growth coming from laboratory studies. Despite not being applicable to cephalopods, Modal Progressio...

Data from three series of scientific bottom trawl surveys held in Mauritania, Senegal and Guinea between 1987 and 1999 are analyzed in order to highlight the major features of structuring elements (general spatial distribu-tion and temporal evolution) of the demersal fish communities of West Africa, in an area subjected to a strong halieutic intens...

The assemblages of demersal fish and associated species of the Senegalese continental shelf are analyzed in order to characterize their diversity and evolution during the 1986-1995 period. The biological data come from an historical series of scientific trawling surveys. The analytical process (dominance curves), as well as the interpretation of th...

Demersal fisheries in the Mauritanian Exclusive Economic Zone (EEZ) are described, with a review of the state of the stocks that are exploited by these fisheries. The assessment of the various stocks is based primarily on the results of the “Groupe de Travail” (GT), held in December 2002 at the Mauritanian fisheries research institute IMROP, Nouadh...

La pêche des poulpes Octopus vulgaris par chalutage est une acti¬ vité économique très importante en Mauritanie depuis la fin des années 1960 (Hatanaka, 1979 ; Guerra, 1997). Une pêche artisanale se développe depuis 1990 (Lamboeuf, 1997). Quand des conflits opposent les composantes industrielles et artisa¬ nales de la pêche mauritanienne au poulpe,...

The growth of Octopus vulgaris (Mollusca: Cephalopoda) in tanks and the sea was modelled and calculated following tagging studies in Senegal. Octopus exhibits a large individual variability in growth and the exponential growth curve is the best fitting theoretical model among other usual models tested. Globally, the growth rates were comparable in...

Le poulpe commun (#Octopus vulgaris$) est très abondant au large des côtes NO-africaines où il est exploité à grande échelle. En Mauritanie, il représente la principale ressource halieutique grâce à la production de la zone de pêche du Cap-Blanc. Les caractéristiques globales de répartition spatio-temporelle de la population d'#Octopus vulgaris$ pr...

Le pulpe #Octopus vulgaris$ est abondant sur les fonds côtiers de la Petite Côte du Sénégal où sa répartition serait plus liée à la disponibilité des proies qu'à d'autres facteurs environnementaux. L'abondance des jeunes devient très importante en été et la pêche artisanale exploite alors préférentiellement cette ressource à partir de deux sites po...

The common octopus Octopus vulgaris is very abundant off the coast of NW Africa, where it is exploited on such a large scale that it is the most valuable fishery product of Mauritania. Considering its economic value and because the stocks have been subjected to very high fishing pressure there since the 1970s, without any apparent long-term decreas...

In the Etang de Thau, France, zooplankton community spatial patterns have a short-term significance (few days) and do not reveal any seasonal characteristics. Inversion of the water flows between the lagoon and the sea plays a major role in structuring and destructuring the biological system: the zooplankton compartment appears to be particularly s...

Dans le but de mieux comprendre certains mécanismes du fonctionnement de l'écosystème lagunaire, ce travail aborde le compartiment zooplanctonique sous l'angle de son organisation spatiale à l'intérieur d'une lagune nord-méditerranéenne (étang de Thau). Un traitement statistique - groupement avec contrainte de contiguïté spatiale - est employé pour...