# How to study the social-ecological impacts of invasive species: the case of the ctenophore Mnemiopsis leidyi in Berre lagoon (Southeast France)

Guillaume Marchessaux

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Guillaume Marchessaux. How to study the social-ecological impacts of invasive species: the case of the ctenophore Mnemiopsis leidyi in Berre lagoon (Southeast France). Vie et Milieu / Life & Environment, 2020, 70. hal-04856894

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# HOW TO STUDY THE SOCIO-ECOLOGICAL IMPACTS OF INVASIVE SPECIES: THE CASE OF THE CTENOPHORE *MNEMIOPSIS LEIDYI* IN BERRE LAGOON (SOUTHEAST FRANCE)

G. MARCHESSAUX

Aix Marseille Univ, Univ Toulon, CNRS, IRD, MIO, Marseille, France
guillaume.gmarchessaux@gmail.com

MEDITERRANEAN LAGOONS
INTERDISCIPLINARITY
COMB JELLYFISH

ABSTRACT. – Berre Lagoon is an ecosystem historically disturbed by strong industrial discharges and significant freshwaters inputs from both natural and anthropogenic (hydroelectric powerplant) sources. While rehabilitation policies initiated in 1994 are already showing some success, the introduction and proliferation of *Mnemiopsis leidyi* since 2005 could limit their effectiveness. The originality of this study is to associate oceanography and sociology to estimate the impact of *M. leidyi* on the functioning of this socio-ecosystem. This article presents an overview of a broad range of results obtained using interdisciplinary approach. It appeared that *M. leidyi* has an impact on plankton community functioning and on human activities, particularly on fishing. Therefore, in the context of biological invasions, the prospects for the rehabilitation of Berre Lagoon remain subject to the unpredictability of nature.

## INTRODUCTION

In the Mediterranean Sea, more than a thousand marine species are considered non-indigenous species (NIS) (Zenetos et al. 2010) and their numbers have been increasing exponentially since the beginning of the 20th century (Katsanevakis et al. 2009, Boudouresque & Verlaque 2010, Zenetos et al. 2010). In the Mediterranean Sea, there are several vectors of species introduction. The main vector is the opening of the Suez Canal between the Red and Mediterranean Seas allowing the entry of Lessepian species into the Eastern Mediterranean basin (63 % of NIS observed in the Mediterranean; Boudouresque & Verlaque 2005). This canal has made the Mediterranean Sea a shortest maritime route for global maritime trade, linking America to Asia, leading to a high level of maritime traffic likely to introduce species (ballast water, fouling). Aquaculture and shellfish farming are also efficient vectors for the introduction of species accompanying fish and other mollusks (Boudouresque & Verlaque 2005, 2012).

While the majority of introduced species do not pose a direct risk to humans; however, 86 Mediterranean NIS are considered to have a strong socio-ecological impact (Katsanevakis et al. 2014), particularly in the coastal zone, the area most studied. Because of the various advantages they present for a range of industries (tourism, trade, agriculture, fishing), coastal environments are the most impacted by human pressures. At the same time, certain of the marine compartments are developing, such as the gelatinous zooplankton (Re et al. 2014, Halpern et al. 2015, Gibbs et al. 2017, Visbeck 2018).

In the Mediterranean Sea, eight species of gelatinous zooplankton are exotic. Five species of cnidarians

entered the Mediterranean via the Suez Canal (*Phyllorhiza punctata* von Lendenfeld, 1884, *Cassiopea andromeda* (Forsskål, 1775), *Carybdea marsupialis* (Linnaeus, 1758), *Marivagia stellate* Galil & Gershwin 2010, *Rhopilema nomadica* Galil, Spanier & Ferguson 1990), while *Goniumemus vertens* A. Agassiz, 1862 was certainly introduced in polyp form with shellfish for shellfish farming (Marchessaux et al. 2017). The ctenophore *Mnemiopsis leidyi* A. Agassiz, 1865 has been transported in the ballast water of commercial ships and *Beroe ovata* Bruguière, 1789 has been accidentally introduced into the Black Sea (Bordehore et al. 2014, Brotz & Pauly 2016). The impact of these alien gelatinous species on the environment and on human activities has been relatively poorly documented. Katsanevakis et al. (2014) reported on the impact of some of them in Europe.

*Mnemiopsis leidyi* is a ctenophore (class Tentaculata, order Lobata) endemic to the American Atlantic coasts: South American coasts, Gulf of Mexico and Chesapeake Bay (Purcell et al. 2001, Mianzan et al. 2010, Costello et al. 2012) and which mainly colonizes estuaries, lagoons or inland seas (Purcell et al. 2001). Areas invaded by *M. leidyi* are generally subject to anthropogenic pressures such as eutrophication or overfishing, the latter favoring the success of *M. leidyi* (Bilio & Niermann 2004, Daskalov et al. 2007). *Mnemiopsis leidyi* was ranked among the 100 most invasive marine species in the world (Lowe et al. 2004).

*Mnemiopsis leidyi* appeared in the Black Sea in 1982 (Fig. 1) (Vinogradov et al. 1989, Reusch et al. 2010, Bolte et al. 2013, Ghabooli et al. 2013) and it has since spread to the Caspian Sea (Vinogradov et al. 1995), the Sea of Marmara (Isinibilir & Kideys 2004) and the Mediterranean Sea (Aegean Sea, Galil et al. 2009; Adriatic Sea,
<figure><img src="image_2.png" /><figcaption>Fig. 1. – Distribution map of the introduction areas of *Mnemiopsis leidyi* in Europe (top) and on French Mediterranean coasts (below). Red cross: no *M. leidyi*.</figcaption></figure>

Shiganova & Malej 2009; North-Western Basin, Boero et al. 2009, Fuentes et al. 2010, Bolte et al. 2013, Ghabooli et al. 2013, Marchessaux et al. 2020a, b) following the hydrodynamic circulation or again by means of shipping. More recently, new invasions were observed in northern Europe, in 2005 in Norway and the Baltic Sea (Javidpour et al. 2006, Oliveira 2007, Javidpour 2008). The organisms in this case were thought to originate from the east coast of the USA (Chesapeake Bay) (Reusch et al. 2010), while the Mediterranean populations were thought to originate from Mexico. On the French Mediterranean coastlines, *M. leidyi* was first formally identified in the Berre Lagoon in 2005 (Fig. 1, Table I, Marchessaux et al. 2020a), and has been episodically present in six other Mediterranean lagoons (Fig. 1, Table I) but the first arrival of *M. leidyi* along French Mediterranean coastlines could have occurred much earlier. *Mnemiopsis leidyi* has

been observed in widely varying conditions of temperature (0 °C-31 °C), salinity (0.1-40) and chlorophyll a concentration (0.02-9.7 µg L⁻¹) reflecting its high ecological tolerance.

From the beginning of the 19th century, the rapid development of modern science led to the increased specialization of scientists. The (re)establishment of dialogue between disciplines is recent. From the 1970s onwards, in the field of the environment, it has been encouraged, if not driven by social demands that submit to researchers' questions that escape their disciplinary divisions (Jollivet 1992, Henry & Jollivet 2002, Claeys-Mekdade 2003, Gerini 2005). Thus, the overall functioning of an ecosystem cannot be explained in a compartmentalized approach alone (Legay 2004, Boudouresque et al. 2020). Neither the life sciences on the one hand nor the human sciences on the other are capable of separately providing
<table><caption>Table I. – Hydrological conditions of invaded French Mediterranean lagoons.</caption><thead><tr><td>Date</td><td>Location</td><td>Latitude</td><td>Longitude</td><td>References</td></tr></thead><tbody><tr><td>2005</td><td>Berre Lagoon</td><td>43.4592</td><td>5.1059</td><td>Marchessaux et al. (2020a)</td></tr><tr><td>2005</td><td>Bages-Sigean Lagoon</td><td>43.1054</td><td>2.9920</td><td>Delpy et al. (2016)</td></tr><tr><td>2005</td><td>Biguglia Lagoon</td><td>42.6263</td><td>9.4649</td><td>Etourneau (2011)</td></tr><tr><td>2009</td><td>Villefranche-sur-Mer bay</td><td>43.6994</td><td>7.3161</td><td>Fuentes et al. (2010)</td></tr><tr><td>2009-2010</td><td>Salses-Leucate Lagoon</td><td>42.8584</td><td>2.9956</td><td>Delpy et al. (2016)</td></tr><tr><td>2010</td><td>Le Grec Lagoon</td><td>43.5379</td><td>3.9433</td><td>Marchessaux & Belloni (2021)</td></tr><tr><td>2011</td><td>Villepey Lagoon</td><td>43.4047</td><td>6.7171</td><td>Marchessaux et al. (2020b)</td></tr><tr><td>2016</td><td>Vaccarès Lagoon</td><td>43.5353</td><td>4.6370</td><td>Marchessaux et al. (2020b)</td></tr><tr><td>2019</td><td>Estomac Lagoon</td><td>43.4445</td><td>4.9536</td><td>Marchessaux et al. (2020b)</td></tr></tbody></table>

complete answers to these questions. Thus, the researcher becomes a “*border-crosser*” (Jollivet 1992) bridging the life sciences and the human sciences in order to grasp the complexity of interactions between ecological and social processes.

Currently, the opening up of research is characterized by a process of knowledge dialogue (Jollivet & Legay 2005). Interdisciplinarity is one of the methods for sharing knowledge and fields (Jollivet & Legay 2005). Interdisciplinarity responds to the dual objective of an articulation between the disciplines involved while preserving the theoretical and methodological specificities of each. The different forms of collaboration between disciplines need to be clearly defined. Claeys & Thian-Bo-Morel (2015) proposed clarification of attempted to elucidate the differences between three possible forms of collaboration between disciplines: multidisciplinary, interdisciplinary and transdisciplinary: “*multidisciplinary can be defined as the aggregation of different disciplines, interdisciplinarity by interpenetration between several disciplines and finally transdisciplinary by challenging disciplinary boundaries that can produce meta-disciplinary*” (Claeys & Thian-Bo-Morel 2015). Interdisciplinarity responds to the dual objective of close interaction between the disciplines involved while preserving the theoretical and methodological specificities of each. Thus, each specialty retains its own study methods (protocols, concepts) but, within the framework of interdisciplinarity, it is essential for its success to create links to build bridges between these specialties (Charaudeau 2010).

This interdisciplinary approach is essential for studying biological invasions. The human aspect must be taken into consideration in the study of biological invasions for a global understanding of the ecology, the impact, and the societal challenge this phenomenon involves (Dalla Bernardina 2010, Javelle et al. 2010, Atlan & Darrot 2012, Pimentel 2014). Indeed, the accidental introduction and invasion of *M. leidyi* in Europe has had a strong impact on invaded ecosystems and human activities. From a sociological point of view, this study deals with a major contemporary issue, relating to what Giddens (1990) calls “*the consequences of modernity*” and its environmental paradoxes. The case study chosen, relating to the anthro-

pogenic causes and consequences of the development of *M. leidyi*, is an innovative research theme in sociology that is part of a broader reflection on “*the place of the animal*” (Staszak et al. 2002) and “*the proliferating nature*” (Claeys & Sirost 2010).

The notion of invasive alien species proposed by Charles Sutherland Elton in his book “*The ecology of invasion by animals and plants*” (Elton 1958) really became widespread in the scientific literature from the 1980s onwards. It has been the subject of passionate academic controversies tending to oppose the human sciences and life sciences. In the United States, this debate was particularly crystallized around the publications of the philosopher Sagoff (1999, 2005), Simberloff (1998, 2003) and Simberloff et al. (2013), founder of the journal Biological Invasion. Sagoff was concerned about the lexical and potentially ideological similarities between the vocabulary of biological invasion ecology and that of xenophobic nationalist policies. In response, Simberloff (2003) defended a precautionary principle, advocating a posture of generalized suspicion towards all new alien species. It is worth noting that the book of Elton (1958) was based upon ecological concepts that were considered as widely outdated by modern ecologists (e.g., Boudouresque & Verlaque 2012).

In France, the beginning of the 2000s was marked by the controversy over the invasive green macroalga *Caulerpa taxifolia* colonizing the *Posidonia oceanica* seagrass meadows of the Mediterranean. In this case, the oceanographers involved played the role of high-profile whistleblower (Meinesz et al. 1993, Boudouresque et al. 1995, De Villèle & Verlaque 1995, Meinesz et al. 2001, Humair et al. 2014). On the other hand, social scientists analyzed these scientific discourses and their media uptake their diffusion in the media as the fabrication of a modern myth (Dalla Bernardina 2010).

At the same time, sociological studies led by naturalist sponsors, notably the International Union for Conservation of Nature (IUCN), were developed (McNeely 2002). These studies were part of a social engineering approach using non-critical perception surveys aimed at formulating awareness campaigns to combat biological invasions. They have been well received in the journal Biological
Invasion, which expresses a cautious opening towards the human sciences (Simberloff et al. 2013). Nevertheless, this was a situation of “science under influence” (Jolivet 1992), depriving the social sciences of their critical power.

In between these two extremes, a dialogue that is both appeased and critical has emerged, often a little on the fringes of the academic power base. For example, in France, the hydrobiologist ethnologist were collaborating, producing constructive focused on around the invasive aquatic plant *Ludwigia peploides* (Menozzi & Dutatre 2007). Other experiments followed on the same principle of critical and peaceful co-construction (Kalaora 1998, Charpentier & Claeys-Mekdade 2006). What these different experiences have in common is that they have opted for “interdisciplinarity from below” (Zuindeau 2006). This mode of interdisciplinarity proposed an entry through objects and fields of study to calm epistemic tensions between the human and social sciences and the life sciences. It is a question, to use the expression of Brendon Larson (Larson 2005), of demilitarizing the problem of biological invasions, this “war of the roses”.

This study on Berre Lagoon is in line with this “interdisciplinarity from below” approach (Zuindeau 2006). It involved submitting to investigation by natural and sociological sciences a complex subject, the proliferation of *M. leidyi*, which they could only fully elucidate through a co-understanding of the interactions between biological and anthropogenic processes in the socio-ecosystem of the Berre Lagoon. In this article an overview of the main results obtained based on a socio-ecological approach are presented to determine the potential impact of the invasive ctenophore *M. leidyi* on the socio-ecosystem of the Berre Lagoon.

## MATERIALS AND METHODS

The creation of a common study protocol linking up the methodological tools of the different disciplines involved was

a fundamental step in the implementation of interdisciplinary research. The interdisciplinary approach adopted in this study combined *in situ* oceanographic data, laboratory analysis and measurements with sociological investigations and citizen science (Fig. 2). This linkage provided a better understanding of the dynamics and possible impacts of the invasion of *Mnemiopsis leidyi* on the socio-ecosystem of the Berre Lagoon.

The conceptual framework of risk was used following formula: Risk = hazard × vulnerability. Risk resulted from the combination of hazards and vulnerability. Risk was defined as the result of damage caused because of interactions between disturbance factors (hazards) and vulnerability factors (use). The ctenophores represented the disturbance or hazard elements, and vulnerability was characterized by the more or less high exposure of humans (the practice of users) to the hazard (Veyret & Reghezza 2006, Gilbert 2009). In this study, hazard was measured by oceanography (presence, abundance of ctenophores, etc.) and vulnerability was analyzed by sociology (observation of lagoon frequentation patterns, behavior of users, etc.). Risk is also an object of discourse for individuals. In this case, the sociological survey records the levels of risk expressed by social actors and their ways of naming and qualifying these risks. In common parlance, when faced with the proliferation of an animal species, social actors tend to talk more about discomfort (Mieulet 2015). From this point of view, discomfort can be defined as the negative consequences experienced by social actors, in this case the users of the Berre Lagoon, when an event occurs, in this case the proliferation of gelatinous zooplankton.

A bimonthly monitoring (temperature, salinity, oxygen, chlorophyll *a*, abundances of zooplankton and ctenophores) was performed in the Berre Lagoon between October 2015 and September 2017 (Marchessaux *et al.* 2020a). Laboratory experiments were performed to study the physiology of *M. leidyi* (respiration, excretion, ingestion, digestion, reproduction, larval growth, and survival in starvation conditions) to determine its invasive potential. The human experiments were characterized by semi-directional interviews with different actors of the lagoons (fishermen, bathers, naturalists, yachting clubs, etc.). Finally, a citizen science was also performed to complete *in situ* monitoring and study the evolution of nuisance caused by cteno-

<figure><img src="image_3.png" /><figcaption>Fig. 2. – Diagram illustrating the strategy for interdisciplinary study of the dynamics and impact of *Mnemiopsis leidyi*. In blue: oceanography; orange: sociology.</figcaption></figure>
<figure><img src="image_4.png" /></figure>

Fig. 3. – **A**: Three-dimensional representation of the abundance of *Mnemiopsis leidyi* (rainbow colors, ind m⁻³) as a function of temperature (°C) and salinity in the Berre Lagoon; **B**: Zooplanktonic and phytoplanktonic bio-masses (µg L⁻¹) during periods of absence or presence of *M. leidyi*. Data from 2010 to 2017 extracted from Marchessaux *et al.* (2020a).

phores proliferations. More details on the *in situ* monitoring are available in Marchessaux *et al.* (2020a) and, data presented in these articles were mainly extracted from this article and presented differently.

## RESULTS AND DISCUSSIONS

The main thread of this work was the perspective between human experiences and the measured. The human experiences concerned the experiences and testimonies of the social actors encountered. This human experience can be sensory, involving the body of individuals and their five senses, sight, touch, smell, taste, and hearing. This experience may be social, taking shape in the relationships between social actors and/or maybe economic, relating to the actors’ losses and gains. Thus, it was a question of analyzing how different physical and socio-economic experiences could lead to a different understanding, definition, and quantification of the same phenomenon, in this case, the causes and consequences of the proliferation of gelatinous zooplankton.

**What is the success rate of Mnemiopsis leidyi invasions in the Berre Lagoon?**

Native to estuarine and lagoon environments, *Mnemiopsis leidyi* was able to maintain itself over a wide range of temperatures (1 °C to 32 °C; Kremer & Reeve 1989, Purcell *et al.* 2001, Lehtiniemi *et al.* 2012) and tolerated significant variations of salinity (0 to 40; Shiganova *et al.* 2004, Grove & Breitburd 2005). In the Berre Lagoon, *M. leidyi* was observed for temperature and salinity comprised between 3 °C and 28 °C and, 0 to 25, respectively (Fig. 3A) with highest abundances, 43 ± 24 ind m⁻³ (data range: 27 ind m⁻³-95 ind m⁻³), comprised between 19-25 for temperature and 22-28 for salinity. *Mnemiopsis leidyi* can also survive in areas with very little oxygen (> 1 mg O₂ L⁻¹; Decker *et al.* 2004, Grove & Breitburd 2005). Under unfavorable dietary conditions, *M. leidyi* can self-digest from its reserves and can thus survive for weeks (Ivanov *et al.* 2000, Yousefian & Kideys 2003, Anninsky *et al.* 2005).

The success of *Mnemiopsis leidyi* in Berre Lagoon was certainly due to a sufficient supply of carbon (Fig. 3B). According to Kremer (1994) the quantity of carbon limiting the development of *M. leidyi* was estimated at 3 µg C L⁻¹. Long-term monitoring data showed that the amount of particulate organic carbon (POC) did not fall below this threshold for the survival of *M. leidyi* (Marchessaux *et al.* 2020a). The sufficient supply of carbon in the Berre Lagoon therefore allowed *M. leidyi* to produce enough eggs (Reeve *et al.* 1989), and to have an optimal growth rate (Rapoza *et al.* 2005, Sullivan & Gifford 2007, Marchessaux 2019).

The other success of *M. leidyi* in native and introduced areas was possible thanks to the presence of refugia areas during winter (Costello *et al.* 2006, Marchessaux *et al.* 2020a). In the Berre Lagoon, the Vaine sub-basin provided favorable conditions (low temperature and salinity variations, sufficient carbon content, low currents) to maintain *M. leidyi* in critical environmental conditions (*i.e.*, cold winters; Fig. 4) (Marchessaux *et al.* 2020a).

**Impact of Mnemiopsis leidyi on the Berre Lagoon socio-ecosystem**

The notion of socio-ecosystem refers to the relationship between Society and the Environment and the effects that one can have on the other. Considering the links

<figure><img src="image_5.png" /></figure>

Fig. 4. – Assessment of the conditions measured in the refugia area of *M. leidyi* in the Berre Lagoon. Redrawn from Marchessaux *et al.* (2020a).
<figure><img src="image_6.png" /><figcaption>Fig. 5. – Overall summary of the interactions identified between *Mnemiopsis leidyi* and the socio-ecosystem of the Berre Lagoon.</figcaption></figure>

between society and the environment, the framework of our interdisciplinary study allowed us to establish a complete inventory of the interactions and impacts of the invasion of *M. leidyi* (Fig. 5).

A voracious predator, *M. leidyi* had a significant predation pressure on the zooplankton community, whose grazing on phytoplankton remained limited in this context. The presence of *M. leidyi* contributed to the eutrophication of the lagoon on the one hand by controlling the zooplankton and on the other hand by contributing to phytoplankton development through the excretion of ammoniacal nitrogen (~ 3 %; Marchessaux 2019) as observed in Chesapeake Bay (3 %; Nemazie et al. 1993) and in York River (4 %; Condon et al. 2009). These hypoxic crises, which generally occur in summer, are fatal for populations of benthic organisms.

The potential competitiveness of *M. leidyi* for the resource had certainly contributed to the decline of the autochthonous cnidarian *Aurelia* spp. (jellyfish) whose observation in the environment became limited in time. In the light of this potential competition between the two gelatinous species, the hypothesis of competition with planktonophagous fish in the lagoon can be proposed.

This has not been tested in our study, but if there was competition, a decrease of commercial fish species could be observed, which could have catastrophic economic

consequences for the professional fishery. Professional fishing was the human activity most impacted by gelatinous species blooms. The damage caused by *M. leidyi* was significant (clogging of nets, mutilation of catches, damage to equipment, increased workload) and involved losses of up to 50 % of the annual revenues. Bathing activity was little affected. The presence of *Mnemiopsis leidyi* was acceptable for bathers because this species is not stinging. On the other hand, this study has determined a threshold of bathers' acceptability (10 ± 8 ind m⁻³). Beyond this threshold of acceptability, the swimmers deserted the beaches of the lagoon. Boating was not affected by the proliferation of *M. leidyi* but, in the case of strong proliferation, damage to the cooling systems of boat engines has been observed.

### *Mnemiopsis leidyi* invasion and rehabilitation efforts

This interdisciplinary study has demonstrated the extent to which current European rehabilitation efforts were potentially counteracted by the presence of *Mnemiopsis leidyi*. To address this issue, based on the data collected in oceanography (abundances of ctenophores and zooplankton, ctenophores gut contents, physiology) and sociology (impact on different activities, discomfort of users, citizen science), we propose two scenarios (Fig. 6).
<figure><img src="image_7.png" /><figcaption>Fig. 6. – Conceptual diagram of the possible scenarios of changes in the functioning of the pelago-benthic food web in the Berre Lagoon in the absence or presence of *Mnemiopsis leidyi*.</figcaption></figure>

**Scenario 1 – No Mnemiopsis leidyi (before introduction):** Without *M. leidyi*, zooplankton exerts a “top-down” control over phytoplankton, decreasing in synergy with the decrease in freshwater and nutrient inputs inducing significantly low eutrophication of the lagoon and limiting hypoxic/anoxic crises. Without ctenophores, *Aurelia* spp. could recover in the lagoon.

**Scenario 2 – With Mnemiopsis leidyi (current configuration):** The presence of a large population of *M. leidyi* counters rehabilitation efforts and helps to maintain eutrophication. *Mnemiopsis leidyi* controls the zooplankton community that can be ingested at a rate of up to 80 % of its abundance per day. This directly results in a reduction in zooplankton grazing pressure on phytoplankton communities. In addition, the N-NH₄ excretion of *M. leidyi* contributes 3.8 % of the ammonium inputs to the lagoon, which also promotes phytoplankton growth via regenerated production. Thus, by a “top-down” and “bottom-up” effect, the population has a favorable effect on the maintenance of eutrophication in the Berre Lagoon.

The issue of combating the proliferation of *M. leidyi* in the Berre Lagoon was raised by more than 80 % of the users encountered. Opinions suggest that controlling the proliferation of *M. leidyi* is one of the priority issues for future management of Berre Lagoon. The contribution of our interdisciplinary study enabled us, with knowledge of the users' wishes in terms of management, to report on the factors favoring the

maintenance of *M. leidyi* and the interactions within the socio-ecosystem. Based on this observation, management measures will be proposed (anti-jellyfish nets, risk maps, etc.).

## CONCLUSION

The convergence of life sciences (LS) and human and social sciences (HSS) responds to a social and political demand, both of which are growing in the context of the development of environmental policies and their application. This *rapprochement* of LS and HSS helps to overcome the problem of the life sciences considering pristine ecosystems in isolation from human influence and it is therefore necessary to consider the human factor in ecological studies. The combination of LS and HSS can give rise to misunderstandings, particularly from the point of view of methodology, which are mitigated by the interdisciplinary approach that consists in the interpenetration of disciplines aimed at the co-construction of scientific protocols and the coproduction of new knowledge that goes beyond the aggregation of disciplinary knowledge.

<figure><img src="image_8.png" /><figcaption>Fig. 7. – Summary diagram of the parameters effecting on the physiology of *Mnemiopsis leidyi* and its role in the socio-ecosystem of the Berre Lagoon.</figcaption></figure>
In fact, the interests and objectives of each discipline are brought together in a reciprocal and mutually beneficial comprehension by excluding the false hierarchy between LS and HSS. The success of interdisciplinarity lies in the acceptance by the life sciences of the critical posture of the human and social sciences and, conversely, the recognition by HSS of the materiality of life as analyzed by the life sciences. This collective practice does not exclude the skills and methodologies of each discipline, but resides in an acculturation over time, respect, and mutual trust from a human and scientific point of view.

This study is in line with this bottom-up interdisciplin-
ary approach, where the two disciplines involved had to
deal with a complex subject, the proliferation of *M. leidyi*,
which they can only fully understand through combined
understanding of the interactions between biological and
anthropogenic processes in the Berre Lagoon (Fig. 7).
The interdisciplinary approach has fully proved its worth
in this work. The testimonies of users have sometimes led
us to seek/question ecological aspects that would not have
been explored in the case of a life science study alone.
Moreover, the contribution of sociology in this work has
represented a real added value in that thanks to the net-
work developed with the users of the lagoon, we were
able to place able to obtain complementary data on the
distribution and the dynamics *in situ* of the ctenophores
and on the other hand the proliferation of *M. leidyi* was
placed within the societal requirements concerning this
socio-ecosystem.

In Berre Lagoon, the installation of *M. leidyi* in con-
junction with the implementation of rehabilitation efforts
in this case illustrates the fragility of the ecosystem his-
torically disturbed by human activities. Heavy freshwater
discharges from the EDF (Électricité de France) hydro-
electric powerplant and industrial and urban discharges
have considerably altered the hydrological functioning
and have thus destroyed a large part of the lagoon’s habi-
tats. The anthropogenic pressures have allowed the arriv-
al and development of invasive species (i.e., *M. leidyi*,
*Gonionemus vertens*, *Acartia tonsa* Dana, 1849, *Ulva* sp.,
etc.). Thus, Berre Lagoon represent anthropized place
where ecological history has conditioned its management
but also the fluctuations of nature.

ACKNOWLEDGEMENTS. – I kindly thank B Belloni and J Gad-
reaud for their help during *in situ* sampling, to the *Microscopie
et Imagerie Marine* (MIM) and *Cultures expérimentales* plat-
forms at MIO (Mediterranean Institute of Oceanography), to
EDF (Électricité de France) for the temperature and salinity
data, to C F Boudouresque for valuable suggestions to improve
the initial manuscript and to M Paul, a native English speaker,
for improving the English text. This work was supported by a
PhD fellowship from the French Ministry of Higher Education
and Research from 2015 to 2018.

REFERENCES

Anninsky BE, Finenko GA, Abolmasova GI, Hubareva ES, Svetlichny LS, Bat L, Kideys AE 2005. Effect of starvation on the biochemical compositions and respiration rates of ctenophores *Mnemiopsis leidyi* and *Beroe ovata* in the Black Sea. *JMBA U K* 85: 549-561.

Atlan A, Darrot C 2012. Les invasions biologiques entre écolo-
gie et sciences sociales : quelles spécificités pour l'outre-mer
français ? *Rev Ecol Sup* 11: 101-111.

Bilio M, Niermann U 2004. Is the comb jelly really to blame for it all? *Mnemiopsis leidyi* and the ecological concerns about the Caspian Sea. *Mar Ecol Progr Ser* 269: 173-183.

Boero F, Putti M, Trainito E, Prontera E, Piraino S, Shiganova TA 2009. First records of *Mnemiopsis leidyi* (Ctenophora) from the Ligurian Thyrrhenian and Ionian Seas (Western Mediterranean) and first record of *Phyllorhiza punctata* (Cnidaria) from the Western Mediterranean. *Aquat Invasions* 4: 675-680.

Bolte S, Fuentes V, Haslob H, Huwer B, Thibault-Botha D, Angel D, Galil B, Javidpour J, Moss AG, Reusch TB 2013. Population genetics of the invasive ctenophore *Mnemiopsis leidyi* in Europe reveal source-sink dynamics and secondary dispersal to the Mediterranean Sea. *Mar Ecol Progr Ser* 485: 25-36.

Bordehore C, Nogué S, Gili JM, Acevedo MJ, Fuentes VL 2014. *Carybdea marsupialis* (Cubozoa) in the Mediterranean Sea: the first case of a sting causing cutaneous and systemic manifestations. *J Travel Med* 22: 61-63.

Boudouresque CF, Verlaque M 2005. Nature conservation, Marine Protected Areas, sustainable development and the flow of invasive species to the Mediterranean Sea. *Sci Rep Port-Cros Natl Park* 21: 29-54.

Boudouresque CF, Verlaque M 2010. Is global warming involved in the success of seaweed introductions in the Mediterranean Sea? *In* Seckbach J, Einav R, Israel A Eds, Seaweeds and Their Role in Globally Changing Environments. Cellular Origin, Life in Extreme Habitats and Astrobiology, Vol 15. Springer, Dordrecht: 31-50.

Boudouresque CF, Verlaque M 2012. An overview of species introduction and invasion processes in marine and coastal lagoon habitats. *Cah Biol Mar* 53(3): 309-317.

Boudouresque CF, Meinesz A, Ribera MA, Ballesteros E 1995. Spread of the green alga *Caulerpa taxifolia* (Caulerpales, Chlorophyta) in the Mediterranean: possible consequences of a major ecological event. *Sci Mar* 59: 21-29.

Boudouresque CF, Astruch P, Bănaru D, Blanchot J, Blanfuné A, Carlotti F, Changeux T, Faget D, Goujard A, Harmelin-Vivien M, Le Diréach L, Pagano M, Perret-Boudouresque M, Pasqualini V, Rouanet É, Ruitton S, Sempéré R, Thibault D, Thibaut T 2020. The management of Mediterranean coastal habitats: a plea for a socio-ecosystem-based approach. *In* Ceccaldi HJ, Hénocque Y, Komatsu T, Prouzet P, Sautour B, Yoshida J Eds, Evolution of Marine Coastal Ecosystems under the Pressure of Global Changes. Springer, Cham: 297-320.

Brotz L, Pauly D 2016. Studying jellyfish fisheries: toward accurate national catch reports and appropriate methods for stock assessments. *In* Mariottini GL Ed, Jellyfish: Ecology, Distribution Patterns and Human Interactions. Nova Publishers: 313-329.

Charaudeau P 2010. Pour une interdisciplinarité “focalisée” dans les sciences humaines et sociales. *Quest Comm* 17: 195-222.
Charpentier A, Claeys-Mekdade C 2006. Invasion de plantes ornementales: modalités d'introduction et mécanismes biologiques déclenchant l'invasion de *Baccharis halimifolia* et *Cortaderia selloana*. *Progr INVABIO*: 151-156.

Claeys C, Sirost O 2010. Proliférantes natures. Introduction. *Études rurales*: 9-22.

Claeys C, Thiann-Bo-Morel M 2015. L'apport de la sociologie à l'analyse des invasions biologiques : retour d'expériences et pistes de recherche pour dépasser déceptions méthodologiques et irritations épistémologiques. *Rev Ecol (Terre et vie)* 70: 175-190.

Claeys-Mekdade C 2003. Le Lien politique à l'Épreuve de l'Environnement. Expériences camarguaises, Peter Lang, PIE, Bruxelles: 240 p.

Condon RH, Steinberg DK, Bronk DA 2009. Production of dissolved organic matter and inorganic nutrients by gelatinous zooplankton in the York River estuary, Chesapeake Bay. *J Plankton Res* 32: 153-170.

Costello JH, Sullivan BK, Gifford DJ, Van Keuren D, Sullivan LJ 2006. Seasonal refugia, shoreward thermal amplification, and metapopulation dynamics of the ctenophore *Mnemiopsis leidyi* in Narragansett Bay, Rhode Island. *Limnol Oceanogr* 51: 1819-1831.

Costello JH, Bayha KM, Mianzan HW, Shiganova TA, Purcell JE 2012. Transitions of *Mnemiopsis leidyi* (Ctenophora: Lobata) from a native to an exotic species: a review. *Hydrobiologia* 690: 21-46.

Dalla Bernardina S 2010. Les invasions biologiques sous le regard des sciences de l'homme. In Barbault R, Atramen-towicz M Eds, Les Invasions biologiques, une Question de Natures et de Sociétés. Éditions Quæ: 65-108.

Daskalov GM, Grishin AN, Rodionov S, Mihneva V 2007. Trophic cascades triggered by overfishing reveal possible mechanisms of ecosystem regime shifts. *Proc Natl Acad Sci USA* 104: 10518-10523.

De Villèle X, Verlaque M 1995. Changes and degradation in a *Posidonia oceanica* bed invaded by the introduced tropical alga *Caulerpa taxifolia* in the north western Mediterranean. *Bot Mar* 38: 79-88.

Decker MB, Breitburg DL, Purcell JE 2004. Effects of low dissolved oxgen on zooplankton predation by the ctenophore *Mnemiopsis leidyi*. *Mar Ecol Progr Ser* 280: 163-172.

Delpy F, Albouy-Boyer S, Pagano M, Thibault D, Blanchot J, Guilhaumon F, Molinero JC, Bonnet D 2016. Identifying the drivers of abundance and size of the invasive ctenophore *Mnemiopsis leidyi* in Northwestern Mediterranean lagoons. *Mar Environ Res* 119: 114-125.

Elton CS 1958. The Ecology of Invasions by Animals and Plants. Methuen publ. Reprinted 2000 by University of Chicago Press: xiv + 181 p.

Etourneau S 2011. Cartographie des peuplements et types de fonds de l'étang de Biguglia. Département de la Haute-Corse – Service de la réserve naturelle de l'étang de Biguglia: 35 p.

Fuentes VL, Angel DL, Bayha KM, Atienza D, Edelist D, Bordehore C, Gili JM, Purcell JE 2010. Blooms of the invasive ctenophore, *Mnemiopsis leidyi*, span the Mediterranean Sea in 2009. *Hydrobiologia* 645: 23-37.

Galil BS, Kress N, Shiganova TA 2009. First record of *Mnemiopsis leidyi* A Agassiz, 1865 (Ctenophora; Lobata; Mnemiidae) off the Mediterranean coast of Israel. *Aquat Invasions* 4: 356-362.

Gerini C 2005. L'interdisciplinarité entre sciences dures et sciences humaines comme retour salvateur vers un état onto-logique aboli par la spécialisation. In À la Croisée des Sciences : Pratiquer et Comprendre l'Interdisciplinarité. MMSH, Aix-en-Provence: 16-17.

Ghabooli S, Shiganova TA, Briski E, Piraino S, Fuentes V, Thibault-Botha D, Angel DL, Cristescu ME, Maclsaac HJ 2013. Invasion pathway of the ctenophore *Mnemiopsis leidyi* in the Mediterranean Sea. *PLoS ONE* 8: e81067.

Gibbs R, Bunce M, Mee LD, Rodwell LD, Rewhorn S 2017. Sources, fate and effects of microplastics in the marine environment: a global assessment. *Glob Change Biol* 9: 10.

Giddens A 1990. The Consequences of Modernity. Stanford University Press: 186 p.

Gilbert C 2009. La vulnérabilité : une notion vulnérable ? À propos des risques naturels. In Becerra S, Peltier A Eds, Risques et Environnement : Recherches interdisciplinaires sur la Vulnérabilité des Sociétés. L'Harmattan: 23-40.

Grove M, Breitburg DL 2005. Growth and reproduction of gelatinous zooplankton exposed to low dissolved oxygen. *Mar Ecol Progr Ser* 301: 185-198.

Halpern BS, Frazier M, Potapenko J, Casey KS, Koenig K, Longo C, Lowndes JS, Rockwood RC, Selig ER, Selkoe KA 2015. Spatial and temporal changes in cumulative human impacts on the world's ocean. *Nat Comm* 6: 7615.

Henry C, Jollivet M 2002. La question de l'environnement dans les sciences sociales en France. Éléments pour un bilan. *Europaea 1-2*, anno VIII: 63-74.

Humair F, Edwards PJ, Siegrist M, Kueffer C 2014. Understanding misunderstandings in invasion science: why experts don't agree on common concepts and risk assessments. *NeoBiota* 20: 1-30.

Isinibilir M, Tarkan AN, Kideys AE 2004. Decreased levels of the invasive ctenophore *Mnemiopsis* in the Marmara Sea in 2001. In Dumont H, Shiganova TA, Niermann U Eds, Aquatic Invasions in the Black, Caspian, and Mediterranean Seas. Nato Science Series IV: Earth and Environmental Sciences, Vol 35. Springer, Dordrecht: 155-165.

Ivanov VP, Kamakin AM, Ushivtzev VB, Shiganova TA, Zhunkova O, Aladin N, Wilson SI, Dumont HJ 2000. Invasion of the Caspian Sea by the comb jellyfish *Mnemiopsis leidyi* (Ctenophora). *Biol Invasions* 2: 255-259.

Javelle A, Kalaora B, Decocq G 2010. De la validité d'une invasion biologique. *Prunus serotina* en forêt de Compiègne. *Études rurales*: 39-50.

Javidpour J 2008. Ecological assessment of the ctenophore invader *Mnemiopsis leidyi* in the Western Baltic Sea. PhD Thesis, Christian-Albrechts-Universität, Germany: 102 p.

Javidpour J, Sommer U, Shiganova TA 2006. First record of *Mnemiopsis leidyi* A Agassiz, 1865 in the Baltic Sea. *Aquat Invasions* 1: 299-302.

Jollivet M 1992. Sciences de la nature/Sciences de l'homme. CNRS Éditions: 589 p.

Jollivet M, Legay JM 2005. Pour une réflexion sur une interdisciplinarité entre sciences de la nature et sciences sociales. *Nat Sci Soc* 13: 184-188.

Kalaora B 1998. Au-delà de la nature, l'environnement: l'observation sociale de l'environnement. *Courr Environ INRA* 35: 107-107.

Katsanevakis S, Tsiamis K, Ioannou G, Michailidis N, Zenetos A 2009. Inventory of alien marine species of Cyprus. *Medit Mar Sci* 10: 109-133.
Katsanevakis S, Acar Ü, Ammar I, Balci BA, Bekas P, Belmonte M, Chintiroglou P, Consoli P, Dimiza M, Fryganiotis K, Gerovasileiou V, Gnisci V, Gülsahin N, Hoffman R, Issaris Y, Izquierdo-Gomez D, Izquierdo-Munoz A, Kavadas S, Koehler L, Konstantinidis E, Mazza G, Nowell G, Önal U, Özen MR, Pafilis P, Pastore M, Perdikaris C, Poursanidis D, Prato E, Russo F, Sicuro B, Tarkan AN, Thessalou-Legaki M, Tiralongo F, Triantaphyllou M, Tsiamis K, Tunçer S, Turan C, Tûrker C, Yapici S 2014. New Mediterranean biodiversity records (October, 2014). *Medit Mar Sci* 15(3): 675-695.

Kremer P 1994. Patterns of abundance for *Mnemiopsis* in U.S. coastal waters: a comparative overview. *ICES J Mar Sci* 51: 347-354.

Kremer P, Reeve MR 1989. Growth dynamics of a ctenophore (*Mnemiopsis*) in relation to variable food supply. II. Carbon budgets and growth model. *J Plankt Res* 11: 553-574.

Larson BM 2005. The war of the roses: demilitarizing invasion biology. *Frontiers Ecol Environ* 3: 495-500.

Legay JM 2004. L'interdisciplinarité vue et pratiquée par les chercheurs en Sciences de la vie. *Nat Sci Soc* 12: 63-74.

Lehtiniemi M, Lehmann A, Javidpour J, Myrberg K 2012. Spreading and physico-biological reproduction limitations of the invasive American comb jelly *Mnemiopsis leidyi* in the Baltic Sea. *Biol Invasions* 14: 341-354.

Lowe S, Browne M, Boudjelas S, de Poorter M 2004. 100 of the world's worst invasive alien species. Updated. The invasive Species Specialist Group (ISSG), Auckland: 1-12.

Marchessaux G 2019. Étude de l'anthroposystème emblématique de l'étang de Berre : approches écosystémique et socio-logique de l'impact du cténaire invasif *Mnemiopsis leidyi*. PhD thesis, Aix-Marseille University: 386 p.

Marchessaux G, Belloni B 2021. Expansion of *Mnemiopsis leidyi* in the French Mediterranean lagoons along the Gulf of Lion. *J Sea Res* 168.

Marchessaux G, Gadreaud J, Martin-Garin B, Thiéry A, Ourgaud M, Belloni B, Thibault D 2017. First report of the invasive jellyfish *Gonionemus vertens* A. Agassiz, 1862 in the Berre Lagoon, southeast France. *BioInvasions Rec* 6(4): 339-344.

Marchessaux G, Faure V, Chevalier C, Thibault D 2020a. Refugia area for the ctenophore *Mnemiopsis leidyi* A. Agassiz 1865 in the Berre Lagoon (southeast France): the key to its persistence. *Reg Stud Mar Sci* 39: 1-18.

Marchessaux G, Nicolas D, Crivelli AJ, Befeld S, Contournet P, Thibault D 2020b. Presence of the introduced ctenophore *Mnemiopsis leidyi* A. Agassiz, 1865 in a lagoon system within the River Rhône delta (southeast France). *BioInvasions Rec* 9(3): 471-481.

McNeely J 2002. The role of taxonomy in conserving biodiversity: an UICN perspective. In Pretoria: Bionet Global Taxonomy Workshop: 203 p.

Meinesz A, De Vaugelas J, Hesse B, Mari X 1993. Spread of the introduced tropical green alga *Caulerpa taxifolia* in northern Mediterranean waters. *J Appl Phycol* 5: 141.

Meinesz A, Belsher T, Thibaut T, Antolic B, Mustapha KB, Boudouresque C F, Chiaverini D, Cinelli F, Cottalorda J-M, Djel-louli A 2001. The introduced green alga *Caulerpa taxifolia* continues to spread in the Mediterranean. *Biol Invasions* 3: 201-210.

Menozzi MJ, Dutartre A 2007. Gestion des plantes envahissantes : limites techniques et innovations socio-techniques appliquées au cas des jussies. Ingénieries-EAT, Irstea: 49 p.

Mianzan HW, Martos P, Costello JH, Guerrero RA 2010. Avoidance of hydrodynamically mixed environments by *Mnemiopsis leidyi* (Ctenophora: Lobata) in open-sea populations from Patagonia, Argentina. *Hydrobiologia* 645: 113-124.

Mieulet E 2015. La prolifération de moustiques vecteurs sur le littoral méditerranéen et dans les départements français d'Amérique : enjeux environnementaux et sanitaires. PhD thesis, Aix-Marseille Univ, Marseille: 436 p.

Nemazie DA, Purcell JE, Glibert PM 1993. Ammonium excretion by gelationous zooplankton and their contribution to the ammonium requirements of microplankton in Chesapeake Bay. *Mar Biol* 116: 451-458.

Oliveira O 2007. The presence of the ctenophore *Mnemiopsis leidyi* in the Oslofjorden and considerations on the initial invasion pathways to the North and Baltic Seas. *Aquat Invasions* 2: 185-189.

Pimentel D 2014. Biological Invasions, Economic and Environmental Costs of Alien Plant, Animal, and Microbe Species. CRC Press: 384 p.

Purcell JE, Shiganova TA, Decker MB, Houde ED 2001. The ctenophore *Mnemiopsis* in native and exotic habitats: US estuaries versus the Black Sea basin. *Hydrobiologia* 451: 145-176.

Rapoza R, Novak D, Costello JH 2005. Life-stage dependent, in *situ* dietary patterns of the lobate ctenophore *Mnemiopsis leidyi* Agassiz 1865. *J Plankt Res* 27: 951-956.

Re V, Sacchi E, Mas-Pla J, Menció A, El Amrani N 2014. Identifying the effects of human pressure on groundwater quality to support water management strategies in coastal regions: a multi-tracer and statistical approach (Bou-Areg region, Morocco). *Sci Total Environ* 500: 211-223.

Reeve MR, Syms MA, Kremer P 1989. Growth dynamics of a ctenophore (*Mnemiopsis*) in relation to variable food supply, I. Carbon biomass, feeding, egg production, growth and assimilation efficiency. *J Plankt Res* 11: 535-552.

Reusch TBH, Bolte S, Sparwel M, Moss AG, Javidpour J 2010. Microsatellites reveal origin and genetic diversity of Eurasian invasions by one of the world's most notorious marine invader, *Mnemiopsis leidyi* (Ctenophora). *Mol Ecol* 19: 2690-2699.

Sagoff M 1999. What's wrong with exotic species? *Phil Public Pol Quart* 19: 16-23.

Sagoff M 2005. Do non-native species threaten the natural environment? *J Agric Environ Ethics* 18: 215-236.

Shiganova T, Malej A 2009. Native and non-native ctenophores in the Gulf of Trieste, Northern Adriatic Sea. *J Plankt Res* 31: 61-71.

Shiganova TA, Dumont HJ, Sokolsky AF, Kamakin AM, Tinenkova D, Kurasheva EK 2004. Population dynamics of *Mnemiopsis leidyi* in the Caspian Sea, and effects on the Caspian ecosystem. *In Aquatic Invasions* in the Black, Caspian, and Mediterranean Seas. Nato Science Series: 4. Earth and Environmental Sciences 35: 71-111.

Simberloff D 1998. Invaders from planet Earth: facing the future. *World Conserv* 97(4)-98(1): 21-23.

Simberloff D 2003. Confronting introduced species: a form of xenophobia? *Biol Invasions* 5: 179-192.

Simberloff D, Martin JL, Genovesi P, Maris V, Wardle DA, Aronson J, Courchamp F, Galil B, García-Berthou E, Pascal M, Pysek P, Sousa R, Tabacchi E., Vilà M 2013. Impacts of biological invasions: what's what and the way forward. *Trends ecol evol* 28: 58-66.
Staszak JF, Blanc N, Cohen M, Lassiter U, Boujot C, Casilli A, Hancock C, Bobbé S, Mauz I, Claeys-Mekdade C 2002. La place de l'animal. *Esp Soc* 110-111: 19-24.

Sullivan LJ, Gifford DJ 2007. Growth and feeding rates of the newly hatched larval ctenophore *Mnemiopsis leidyi* A Agassiz (Ctenophora, Lobata). *J Plankt Res* 29: 949-965.

Veyret Y, Reghezza M 2006. Vulnérabilité et risques. L'approche récente de la vulnérabilité. *Ann Mines*: 9-13.

Vinogradov ME, Shushkina EA, Musaeva EI, Sorokin PY 1989. A newly acclimated species in the Black Sea: the ctenophore *Mnemiopsis leidyi* (Ctenophora: Lobata). *Oceanology* 29: 220-224.

Vinogradov ME, Shushkina EA, Bulgakova YV, Serobaba II 1995. Consumption of zooplankton by the comb jelly *Mnemiopsis leidyi* and pelagic fishes in the Black Sea. *Oceanol Russian Acad Sci* 35: 523-527.

Visbeck M 2018. Ocean science research is key for a sustainable future. *Nat Comm* 9: 690.

Yousefian M, Kideys AE 2003. Biochemical composition of *Mnemiopsis leidyi* in the southern Caspian Sea. *Fish Physiol Biochem* 29: 127-131.

Zenetos A, Gofas S, Verlaque M, Çinar ME, Garcia Raso JE, Bianchi CN, Morri C, Azzurro E, Bilecenoglu M, Froglia C 2010. Alien species in the Mediterranean Sea by 2010. A contribution to the application of European Union's Marine Strategy Framework Directive (MSFD). Part I. Spatial distribution. *Medit Mar Sci* 11(2): 381-493.

Zuindeau B 2006. Le réseau comme forme d'organisation de l'interdisciplinarité "par le bas": l'exemple de développement durable et territoires fragiles. *Nat Sci Soc* 14: 286-292.
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