Francesc Maynou

Spanish National Research Council | CSIC · Institute of Marine Sciences

Rhodolith beds, recognized as biodiversity hotspots with high ecological and conservation importance, face local anthropic pressures, including trawl fishing. However, monitoring the diversity associated with this sensitive biogenic habitat in the deep waters of the Mediterranean Sea is challenging. Traditional monitoring methods, such as experimen...

The ecological importance of rhodolith beds stems from their role as structurally complex three-dimensional habitat formed by free-living red calcareous algae. Their structural singularity is due to the great variety of complex and branching morphologies exhibited by rhodoliths that create interstitial spaces and increase their surface area. This i...

The ecological importance of rhodolith beds lies in the fact that they are a structurally complex three-dimensional habitat formed by free-living red calcareous algae. The habitat complexity increases the ecological niches for cryptofauna and provide refuge for a high number of organisms, which is why they are considered biodiversity hotspots. Thei...

Maërl habitats are composed of coralline red algae species that can live freely rolling on the seabed and forming nodules, the so-called rhodoliths, or incrusted forming coralligenous habitats. Maërl habitats are generally distributed in the Mediterranean at a depth of between 30 m and 70 m and are considered one of the most emblematic Mediterranea...

Los fondos marinos siguen siendo grandes desconocidos. Frente a los paisajes terrestres, más accesibles y familiares, la mayor parte de ellos permanecen inexplorados, siendo un enorme desafío para la investigación científica. Este libro da a conocer los paisajes submarinos de distintas zonas del Mediterráneo peninsular: unos fondos singulares y poc...

In this study, we tested cost effective monitoring tools using static video, environmental DNA and hydroacoustics in a rhodolith bed in the Menorca Channel (Western Mediterranean) along a conservation gradient including a well-preserved area. We compared the effectiveness of the different techniques to assess their capacity to inform on the ecologi...

A semiquantitative model using the software Mental Modeler was developed for maërl beds in the Western Mediterranean. The conceptual model represents the multiple interaction between environmental and human factors happening in a maërl bed system, the key component of our model. We ran “what if” scenarios to explore the potential response of maërl...

Size-spectrum models are good candidates to examine the effects of fishery management because predation and fishing are largely body-size dependent. We examine the effects of increasing trawl fisheries' selectivity through the application of a size-spectrum model to a "continental shelf system" in the NW Mediterranean. This system is sustained by d...

Commission Decision of 25 February 2016 setting up a Scientific, Technical and Economic Committee for Fisheries, C(2016) 1084, OJ C 74, 26.2.2016, p. 4–10. The Commission may consult the group on any matter relating to marine and fisheries biology, fishing gear technology, fisheries economics, fisheries governance, ecosystem effects of fisheries, a...

Rodolith beds are aggregations of free-living red coralline algae that can extend down to 100 m on sedimentary continental shelves; these are also known as maërl beds. These beds are highly productive and an important biogenic deposit of calcium carbonate on the planet. In the Mediterranean, their protection is deficient and maërl beds frequently o...

In this study, we adopted a seascape approach to evaluate how biophysical factors influence the distribution and diversity of species’ biological attributes in benthic communities associated with rhodolith bottoms.

The current European Union fisheries policy encourages improving handling practices to increase the survival of discards. Trawling on the Mediterranean upper slope often generates over 30% of discards of the total catch. Among other species, Nephrops norvegicus juveniles are abundantly returned to the sea, sometimes exceeding 40% of discarded bioma...

This study aims to evaluate the diversity of species associated to rhodolith bottoms of three Mediterranean continental-shelf selected areas with the objective of finding how biophysical conditions influence the species distribution and diversity of benthic communities from rhodolith bottoms

In this study we examine which environmental factors shape the variation in abundance of rhodoliths in four study areas along the Western Mediterranean Sea. These areas were recorded with a remoted operated vehicle (ROV) getting georeferenced video data from the seafloor. Rhodolith abundance was modelled by means of boosted-regression trees (BRT) i...

Worldwide climate change will influence the spatial distribution and status of exploited fish stocks, often in uncertain ways with cascading effects on the social-ecological systems depending on them. Likewise, changes in sociopolitical conditions influencing consumer demand, fuel, and fish prices may jeopardize the viability of fisheries. Predicti...

The formation of ex-vessel price of two important Mediterranean fisheries products (hake and red shrimp) was studied through an inverse demand approach, using data from the Catalonia bottom trawl fishery (NW Mediterranean). In both species, the landings by commercial category (proxy for fish size) and total landings determined the daily price fetch...

The distribution of hermaphroditism in fishes has traditionally been mainly explained by its dependence on biotic factors. However, correlates with major abiotic factors have not been investigated on a quantitative basis and at a global scale. Here, we determined the incidence of hermaphroditism in fish at the family and species level, tested the h...

A bioeconomic model was built to assess the contribution of more selective trawl nets to the objectives of the European Multi-Annual Plan for demersal fisheries in the Western Mediterranean (WM MAP). The biological submodel was parameterized with age-structured population parameters for the five target stocks in the WM MAP (European hake, red mulle...

a multiannual plan for Mediterranean demersal fisheries came into force with the objective to reduce the overexploitation of fisheries in the region by implementing effort control regimes. These measures, however, have the potential to adversely impact the local employment and profitability of the fisheries. In this paper, we examine scenarios on t...

The catch of large quantities of sublegal‐sized fish and shrimp is a pervasive feature of bottom trawl fisheries, particularly in the Mediterranean demersal mixed fisheries where regulations traditionally allow small mesh sizes. To address these concerns, two bottom trawl net selectivity trials were carried out in 2019 and 2020 on fishing grounds w...

The exploitation of mixed fisheries leads to trade-offs between fisheries rent, production (landings) and resource conservation because harvest rent cannot be optimized simultaneously for all species. Additionally, the exploitation of mixed fisheries by heterogeneous fleets complicates their management because of the necessity to allocate catch or...

Fishing communities in the Mediterranean Sea face challenges in dealing with Common Fisheries Policy (CFP) ecosystem-based management measures aimed at reducing fishing effort and implementing partial closures of fisheries. The Participatory Action Research method is used here as a “pilot experience” to gather reactions from fishers, scientists and...

The recent establishment of the “landing obligation” under the reformed EU Common Fishery Policy has the twofold objective of reducing the excessive practice of discarding unwanted catch at sea and encouraging more selective and sustainable fisheries. Within this context, the awareness of the spatial distribution of potential unwanted catches is im...

A multi-annual generalized depletion (MAGD) model was applied to the data-limited Mediterranean sandeel boat seine fishery in Catalonia. The results show that catch and effort data at high temporal frequency (month), complemented with biological information on mean body weight and initial estimates of natural mortality and time of recruitment to th...

We built a simulation model based on Dynamic Energy Budget theory (DEB) to assess the growth and reproductive potential of the native European clam Ruditapes decussatus and the introduced Manila clam Ruditapes philippinarum under current temperature and pH conditions in a Portuguese estuary and under those forecasted for the end of the 21st c. The...

Current fishing practices often do not allow adequate selection of species or sizes of fish, resulting in unwanted catches, subsequently discarded, with the consequent negative effects on both marine communities and fisheries profitability. The cross-analysis of density patches of potential unwanted catches and distribution of fishing effort can su...

We built a simulation model based on Dynamic Energy Budget theory (DEB) to assess the growth and reproductive potential of the Manila clam Ruditapes philippinarum under different temperature and pH conditions, based on environmental values forecasted for the end of the 21st c. under climate change scenarios. The parameters of the DEB model were cal...

The aim of this paper is to evaluate fishing capacity by identifying socioeconomic drivers while considering the current resources state in Northwestern Mediterranean fisheries. The case-study is focused on demersal fisheries from the province of Girona (NE Spain), carried out by small scale polyvalent units and bottom trawlers, with purse seiners...

The landing obligation in the revised European Union Common Fisheries Policy allows for exemptions to obligatory landing of the entire catch for species for which “high survival” of discards can be demonstrated. Nephrops norvegicus is an important target species in many fisheries across Europe in the Mediterranean Sea, NE Atlantic Ocean and North S...

The original article has been corrected. A mistake in the author name E. Ramírez-Romero has been corrected.

Discards is an important issue in fisheries around the world. The spatial management of discards has attracted interest as a potential tool for minimizing the unwanted catch. The aim of the present work was to identify areas with high quantities of bottom trawl discarded catch regarding species subjected to MCRS, in six areas of southern European w...

We studied the effect of climate change on the potential spawning habitats of two marine small pelagic fishes. We examined the projected changes in the potential spawning habitat of the summer-spawning anchovy (Engraulis encrasicolus) and round sardinella (Sardinella aurita) in the northwestern Mediterranean by combining the regionalized projection...

Numerical modeling is a key tool to complement the current physical and biogeochemical observational datasets. It is essential for understanding the role of oceanographic processes on marine food webs and producing climate change projections of variables affecting key ecosystem functions. In this work, we evaluate the horizontal and vertical patter...

Seasonal and spatial vertical profiles of data and model outputs, and much more

The viability of Mediterranean marine fisheries is increasingly under threat due to the low biological productivity of overexploited stocks, low economic performance of the fishing units, and offer of unattractive jobs, among other. This has resulted in a decrease of 30% in the number of fishing units active in European Union Mediterranean fisherie...

The Multiannual Management Plan embedded in Regulation EU 2019/1022 of the European Parliament and of the Council of June 20, 2019, envisages to reform Mediterranean demersal fisheries to restore stocks to maximum sustainability yields by 2025. This paper leverages a bioeconomic model based on a specific case study of the Western Mediterranean Sea...

The EU Landing Obligation (LO) is inspired by an environmental concern. Bycatches cannot be thrown at sea anymore but brought to land because of many (ethical) and mostly environmental concerns. Discards, in fact, can generate negative impacts on the marine ecosystems and ecological equilibrium, given increased mortality in fish populations and imp...

Here we used a method of morphological niche analysis, previously shown to be an effective predictor of invasion success, to investigate morphological relationships of sagittae otoliths of Lessepsian (Red sea species entering the Mediterranean through the Suez Canal) fishes within the morphospace of the corresponding receiving taxonomic groups. Ove...

Management alternatives based on fishing effort for the demersal fisheries in the western Mediterranean were tested, with the novelty of examining management alternatives at temporal scales smaller than one year. Nine scenarios were considered on the basis of input control: decrease in the number of fishing days, which may correspond to cessation o...

We investigated the effects of three sea surface oceanographic variables (temperature, salinity and chlorophyll a) on the abundance of eggs and larvae of two summer‐spawning species in the NW Mediterranean sea, the anchovy Engraulis encrasicolus and the round sardinella Sardinella aurita, based on data from ichthyoplankton surveys carried out in th...

Trawling activities are mainly driven by fishermen decisions on where to fish, market demands and fishing regulation. But, the ecological condition of benthic ecosystems feedback on fishermen through their ability to provide catch. In this complex interacting matrix, small decisions such as fishing over certain habitats, discarding fractions of the...

Aiming to end the practice of discarding unwanted catches back to the sea within European marine waters, an obligation to land the catches of all regulated commercial species was introduced with the Common Fisheries Policy, with required implementation by the first of January 2019. The implementation of this new fisheries regulation urges the defin...

The joint viability, or co‐viability, of a Mediterranean Sea mixed demersal fishery was examined by applying a bioeconomic fisheries model to the main seven target stocks of the fishery under biological, social and economic constraints. The stocks of interest were hake, black‐bellied angler, deep‐water rose shrimp, red mullet, blue and red shrimp,...

Minimizing unwanted catches is a major milestone for achieving sustainable fisheries. In the framework of the Common Fisheries Policy, a landing obligation is being established progressively in European waters (Article 15, EU Regu-lation 1380/2013). Supplementary management measures have been proposed to support and enhance the effectiveness of thi...

We investigated the impact of the EU landing obligation in European fisheries by analysing stakeholder 17 perceptions to help identify shortcomings that might lead to obstacles to implementation and possible 18 utilization types. We used semi-structured interviews with 27 experts from 8 countries grouped in 6 19 stakeholder types (fishing industry;...

In the European Union, discards represent a major source of undocumented mortality, contributing to the overfishing of European fish stocks. However, little attention has been given by the scientific community to discards in the European Union’s small-scale fisheries (SSF). This is mainly due to the fact that discards are mostly generated by indust...

We assessed the effect of the European discards ban on the profitability of bottom trawlers in a case study fishery (GSA06, NW Mediterranean) in the transition period 2017-2018, when the species that characterize the fishery, viz. hake and red mullet, fall under the discards ban. We used the results of Sola and Maynou (2018) to simulate the adoptio...

We studied the relative catch performance of a modified trawl fitted with an extension piece using a 90º turned mesh (T90) in comparison with a standard trawl net used in NW Mediterranean bottom trawl fisheries employing a diamond mesh net. The comparison was made by means of paired experimental hauls using the same fishing vessel with alternate de...

The EU Landing Obligation (LO) bans discards to incentivize a more selective and sustainable fishery. This regulation may induce a cost to the fishing industry that could be transferred to final fish consumers. We aim to assess the consumers’ reservation price for a sustainable and selective fishery. The methodology follows two steps: We first asse...

There is currently very little information on the survival of discards of unwanted and unregulated catches of invertebrates after the stresses caused by capture. A great number of the unregulated invertebrate species form the basis of essential fish habitats for important fisheries resources such as hake, red mullet and cuttlefish. Thus, data on th...

With the full implementation of the landing obligation on 1 January 2019, In European waters it will become mandatory for the trawling fleet to land at port all catches of certain species because, according to Article 15 of the new European Common Fisheries Policy, the species subject to the minimum conservation reference size (MCRS) cannot be disc...

European hake (Merluccius merluccius) is an important commercial fisheries species that shows growth overfishing, with catches basically focused on juveniles. This study assesses the benefit of closing a coastal area (an essential habitat for European hake recruits) to fishing, in addition to other alternatives of spatial management, compared with...

Vessel monitoring systems (VMS) represent a tool that can provide information on the spatial and temporal distribution of fishing activity and a quantitative evaluation of the fishing effort at both spatial and temporal scales. The aim of this study was to characterize the spatio-temporal structure of the Catalan purse-seiner fishing effort directe...

Detecció d’una població de Pseudosquillopsis cerisii (Roux, 1828) (Crustacea, Stomatopoda, Parasquillidae) a la Mediterrània nord-occidental S’ha detectat una població de Pseudosquillopsis cerisii, un crustaci estomatòpode molt poc conegut a la Mediterrània nord-occidental. En aigües mediterrànies, aquesta espècie només era coneguda fins ara per un...

Since the first introduction of the landing obligation (a.k.a. Discard ban) in 2015, the EU Mediterranean fisheries are facing some unforeseen challenges. The demersal bottom trawl fisheries, being the most significant contributors to the so-called ‘discard problem’, are confronted with the greatest challenges. Data from the Italian and the Greek f...

Assessments of small-scale, coastal fisheries are often hindered by the lack of complete data sets fulfilling the requirements of conventional stock assessment methods In contrast, existing information from the regular monitoring of fisheries coupled with data-limited assessment methods can help provide the information needed for effective manageme...

Abstract In the European Union, discards represent a major source of undocu-mented mortality, contributing to the overfishing of European fish stocks. However, little attention has been given by the scientific community to discards in European Union Small Scale Fisheries (SSF). This is mainly due to the fact that discards are mostly generated by in...

Experimental fishing trials with standard (control) and modified trammel nets were conducted to assess the possible reduction of discards. The standard trammel net was the commercial net used in the area (80 mm stretched mesh inner panel) targeting Sepia officinalis. This configuration produced 19% discards in weight. The modifications researched w...

A methodological framework that could facilitate the assessment of the effects of the Landing Obligation (LO) on the Good Environmental Status (GES) and socioeconomic sustainability of Mediterranean fishery systems

Knowing the variations of planktonic cnidarians under climate change conditions is of importance due to the key role of carnivorous gelatinous zooplankton in the pelagic ecosystem. We investigated the abundance, spatial distribution, species richness and community structure of planktonic cnidarians in a temperate area, the NW Mediterranean, during...

The seminal work by Baumol et al. (1982) has highlighted the importance of analyzing firms' costs structure. This allows to design proper policy measures and to understand the impacts of those policies in markets. The note presents an original method and an application for testing costs subadditivity in the fishery sector, by using a system of supp...

The estimated impact of the EU Landing Obligation was investigated, which bans discards of regulated species, in South European fisheries through stakeholders' perceptions with the intention to identify implementation shortcomings and practicalities that might lead to obstacles to enforcement. Structured interviews were conducted with 173 fishers i...

Marine ecosystems evolve under many interconnected and area-specific pressures. To fulfil society's intensifying and diversifying needs while ensuring ecologically sustainable development, more effective marine spatial planning and broader-scope management of marine resources is necessary. Integrated ecological–economic fisheries models (IEEFMs) of...

The EU Common Fishery Policy through the Landing Obligation attempts to discourage the release of potentially dead and dying animals back to the sea from commercial fishing. An important part of the discarded biomass in the trawl fishery are species with low or no economic value but with high key ecological role, such as crustaceans. There is very...

The aim of this work was study the relationship between exposure time on deck of trawlers and the potential post release survival of discardable Nephrops norvegicus. To study the survival vitality, a Semi-quantitative Assessment (SQA) was carried out. The SQA takes into account indicators such as mobility and lesions produced in organisms. We defin...

In the area surrounding the Ebro Delta, similar to the rest of the north-western Mediterranean Sea, the sardine (Sardina pilchardus), one of the most exploited small pelagic fishes, has suffered a decreasing trend in abundance and biomass in the last decade, with low values in evidence since 2007. The dependence of this species on environmental fac...

Vulnerability of key benthic and by-catch species

D2-15-Guidance-on-Promoting-Survival-of-Discarded-Fish