Red Shrimp Aristeus Antennatus Research Articles

Description of a first-settled stage of Aristeus antennatus (Risso, 1816) and new insights into distribution and life history of early juveniles in the NW Mediterranean sea

Knowledge on settlement stages of marine fauna is scarce, especially for mobile organisms such as crustaceans. This is most probably explained by the difficulty of capturing them at great depths in addition to their short lifespan and preference for special habitats. In the case of the red shrimp Aristeus antennatus (Risso, 18,16), a species of outstanding importance in many Mediterranean fisheries, there is an important lack of knowledge regarding development between pelagic larval to benthic juvenile-adult phases. As a contribution to fill this gap, in the present study a first-settled stage of the red shrimp is described based on a specimen collected off Formentera (Algerian Basin, western Mediterranean) during October of 1996 at 1594 m depth with a Macer-GIROQ suprabenthic sledge. As a complement to this description, the seasonal distribution and density of small juveniles of A. antennatus (caparace length <16 mm) captured in the Balearic Basin during OTSB-14 bottom trawls performed between the years 2007–2020 at more than 1000 m depth is mapped and discussed. From these distribution maps, an increase in captures of juveniles from autumn to summer can be appreciated, as well as a phenomenon of migration of these small individuals from inner to outer regions of the Balearic Basin. Finally, a theoretical reconstruction of the early life history of these small juveniles, starting at hatching in July, which consistently fits with the size of the first-settled stage described here, is provided.

Genetic Demography of the Blue and Red Shrimp, Aristeus antennatus: A Female-Based Case Study Integrating Multilocus Genotyping and Morphometric Data.

In this study, we quantified the three key biological processes, growth, recruitment, and dispersal pattern, which are necessary for a better understanding of the population dynamics of the blue and red shrimp Aristeus antennatus. This marine exploited crustacean shows sex-related distribution along the water column, being females predominate in the middle slope. The present study attempts to fill the existing gap in the females’ genetic demography, as scarce knowledge is available despite being the most abundant sex in catches. We analyzed morphometric data and genotyped 12 microsatellite loci in 665 A. antennatus females collected in two consecutive seasons, winter and summer 2016, at the main Mediterranean fishing ground as a model. Almost every female in summer was inseminated. Five modal groups were observed in both seasons, from 0+ to 4+ in winter and from 1+ to 5+ in summer. Commercial-sized sorting based on fishermen’s experience resulted in a moderate-to-high assertive method concerning cohort determination. Genetic data pointed out females’ horizontal movement between neighboring fishing grounds, explaining the low genetic divergence detected among western Mediterranean grounds. Our results could represent critical information for the future implementation of management measures to ensure long-time conservation of the A. antennatus populations.

An evaluation of the genetic connectivity and temporal stability of the blue and red shrimp Aristeus antennatus: a case study of spawning females\u2019 grounds in the Western Mediterranean Sea

The blue and red shrimp Aristeus antennatus has been intensively exploited by trawling fishery in the Western Mediterranean Sea. Implementation of an adequate management plan needs complete genetic data of the non-spawning and spawning grounds of the species. During the reproductive period, the species forms spawning aggregations in the middle slope, mainly constituted of mature females carrying spermatophores. Seven spawning females’ grounds in the Western Mediterranean Sea from Gulf of Lions (France) to Cabo de Palos (Spain) were sampled during two consecutive years, 2016 and 2017. This study assessed for the first time the levels of genetic diversity within spawning grounds, the genetic divergence among them and estimated the degree of temporal genetic stability using multilocus genotyping. Our results showed a high connectivity of the spawning females’ grounds that remains stable during the two analysed years, explained by passive larval dispersal, together with juveniles and adults’ migration. We advise that a future management plan for A. antennatus fishery should consider the Mediterranean Subarea GSA6 as a single unit, but it should be combined with local monitoring in order to ensure the sustainable exploitation of the populations.

Abundance and distribution of the deep-sea shrimp Aristeus antennatus larvae along the eastern Spanish Mediterranean coast (GSA 6)

The deep-sea blue and red shrimp Aristeus antennatus is a valuable fishing resource in the Northwestern Mediterranean Sea, currently under a local co-management plan in the port of Palamós (Spain). The management measures, although effective, might benefit other ports due to the dispersal patterns of the species pelagic larvae. Gathering information about A. antennatus larval distribution is a key step to describe these patterns, towards the establishment of well-dimensioned management measures. After a first detection of its larvae as the dominant species in the decapod community in Blanes submarine canyon, this broader approach tackles the entire management area along the Eastern Spanish Mediterranean coast (Geographic Subarea 6; GSA 6). Zooplankton sampling was carried out at 101 stations in surface waters (0.5–1 m) and in 8 stations in stratified vertical sampling (0–1200 m) during July–August 2016. Over 6500 A. antennatus larvae of all known stages were found, the first protozoea (PZ I) representing over 95% of the total. This is the first study taking into account the vertical migration of A. antennatus larvae, and we observed a broad distribution of PZ I throughout the water column. Plankton observations of the species larval distribution were supported by an Individual-Based Model suggesting aggregations in the northern submarine canyons, influenced by cold waters from the Northern Current and the geomorphology of the Ibiza Channel. The present study proposes a division of the GSA 6 in three zones to improve fishery management measures. • Aristeus antennatus larvae are aggregated in submarine canyon areas. • The highest larval abundance is found in the first 50 m of the water column. • PZ I was found throughout the water column from spawning ground depth to surface. • Plankton survey data validate numerical simulations of dispersal patterns. • We suggest the division of GSA 6 in three zones for fisheries management.

Potential factors influencing the condition of demersal sharks in the Mediterranean deep sea ecosystems

The Alboran Sea and the Balearic Islands are two contrasting areas in terms of primary productivity. The former is among the most productive areas of the whole Mediterranean Sea, whereas the Balearic Islands is among the less productive ones in the western Mediterranean. The two areas also show different patterns in the bottom trawl fishing footprint. In the Alboran Sea, the fishing effort on the upper slope is much higher than in Balearic Islands. However, the opposite applies to the middle slope, the vast majority of it remaining unexploited in Alboran Sea, whereas a widespread fishery targeting blue and red shrimp Aristeus antennatus develops in Balearic Islands.Galeus melastomus is a small demersal shark species inhabiting slope bottoms, where adults and juveniles are segregated and concentrate in the middle and upper slope, respectively. It feeds intensively on mesopelagic preys which, in turn, feed on low trophic level organisms close to primary producers. In this work we aimed to study the effect of surface primary production on the condition of deep sea demersal communities. We compared the condition, diet and potential intra- and inter-species competition for feeding resources in the juveniles of G. melastomus between Alboran Sea and Balearic Islands. The comparisons of Le Cren’s relative condition factor, and hepatosomatic and digestivosomatic indices evidenced an opposite pattern to that a priori expectable: better condition in the less productive area. The analysis of stomach contents showed similar diets in both areas, but lower food ingestion in Alboran Sea than in Balearic Islands. Different abundances of potential intra- and inter-specific competitors for feeding resources in the two areas, apparently linked to the different fishing footprints, seems the most likely explanation for the better nourished individuals in Balearic Islands. Whereas juveniles of G. melastomus dominate the shark community in the Balearic Islands upper slope, where the presence of adults of this species is almost negligible, in Alboran Sea this stratum is dominated by adults and potential competitors of other small demersal shark species. All shark species together, including G. melastomus, showed abundances 38% higher in Alboran than in Balearic Islands. Our results show that condition of deep sea demersal fish is ruled by complex inter-relationships among different factors, needing the combination of biological, ecological and fisheries knowledge to understand its variability.

Larval transport of Aristeus antennatus shrimp (Crustacea: Decapoda: Dendrobranchiata: Aristeidae) near the Palamós submarine canyon (NW Mediterranean Sea) linked to the North Balearic Front

Marine fronts are oceanographic drivers for marine species dispersal, especially for their pelagic organisms like the larvae. Larvae can aggregate at the front and consequently have a limited dispersal, which in turn reduces the connectivity between marine populations. Due to the high variations in the ocean, the fronts also have annual changes (i.e., its formation period, gradient, and position), which have poorly-documented effects on larval retention. In the northwestern Mediterranean Sea, a surface density front is localized across a continental margin which is also indented by submarine canyons. There, an abundant population of the commercial deep-sea blue and red shrimp Aristeus antennatus (Crustacea: Decapoda: Dendrobranchiata: Aristeidae) inhabits the seafloor. Each summer, the shrimp offspring are released in pelagic deep-sea and access the superficial waters divided by the density front. In this study, we focused on the interannual variability of the density front influence on the larval transport of shrimps and its repercussions on the potential connectivity between shrimp populations at each front side. A particle-tracking model simulated the larval transport of A. antennatus in hydrodynamics of the northwestern Mediterranean Sea between the years 2006 and 2016. Larval drift distance and seawater density were correlated by 98%. Over the years 2006–2016, the front region retained 86% of larvae, but this rate yearly varied due to changes in density gradient and position of the front. For example, in 2010, 48% of larvae connected to zones south of the front when the density gradient was relatively low. In 2015, 99.2% of larvae were retained in the front region when the latitudinal front position and density gradient were relatively high. Interannual variability of the front position was potentially related to the strength and position of mesoscale circulation patterns. Our findings suggest that the larval retention on habitats favored by canyon productivity because of the front could explain the persistent abundance of A. antennatus population. This information is important to set or improve the fisheries management in zones with strong interannual hydrodynamic variability.

Genetic analyses reveal temporal stability and connectivity pattern in blue and red shrimp Aristeus antennatus populations

Temporal variability of the genetic structure and connectivity patterns of the blue and red shrimp Aristeus antennatus in the seven most important fishing grounds of the Western Mediterranean Sea, were assessed using twelve microsatellite loci during 2 consecutive years (2016 and 2017), in a total of 1403 adult individuals. A high level of geographical connectivity among groups was observed in the two studied years. In fact, no significant geographical differentiation was found in 2016 (FST = 0.0018, p > 0.05), whereas it was indicated in 2017 (FST = 0.0025, p < 0.05). This small divergence in 2017 was not attributed to the distance among locations nor to the effect of the Ibiza Channel. Significant allele frequency changes were found at local level between the 2 years (FCT = 0.0006, p < 0.05), mainly due to Blanes’ fishing ground. Larval dispersal from the North to the South through the main superficial current supports the high level of connectivity pattern found. The temporal genetic instability detected in the Blanes’ fishing ground could be explained by oceanographic temporary features. Our findings evidence only one biological unit in the study region and establish the baseline for an inter-federal management plan of A. antennatus.

Discovery of SNP markers of red shrimp Aristeus antennatus for population structure in Western Mediterranean Sea

Aristeus antennatus is one of the most exploited and economically important resource for fisheries in the Western and Central Mediterranean Sea displaying low population differentiation with mitochondrial and microsatellite markers. The recent development of Genotyping-by-Sequencing (GBS) methods may contribute to the discovery of SNPs and the assessment of genetic differences between populations of this species for fisheries management. Using samples from four geographical sites in Western Mediterranean and Eastern Atlantic, 115,071 putative SNPs were detected. After the stringent quality control measures and the filtering procedure, 232 SNP loci were discovered. Finally, we selected 80 SNP subset panel for Fluidigm Dynamic array application. The results showed significant differentiation among populations from the four sampling sites. Population assignment power and patterns of population differentiation were comparable between the two SNP panels. These markers represent a useful tool for future genetic application of A. antennatus populations.

Morphological description of the first protozoeal stage of the deep-sea shrimps Aristeus antennatus and Gennadas elegans, with a key

Accurate information on commercial marine species larvae is key to fisheries science, as their correct identification is the first step towards studying the species’ connectivity patterns. In this study, we provide a complete morphological description of the first protozoeal stage of the valued deep-sea blue and red shrimp Aristeus antennatus and of the small mesopelagic shrimp Gennadas elegans. These two larval morphologies previously posed a risk of misidentification, thus hindering the study of A. antennatus larval ecology and dynamics in the context of fisheries science. Using specimens caught in the plankton at various locations in the Northwestern Mediterranean Sea and identification confirmed by molecular methods, the larvae of A. antennatus and G. elegans are distinguished from each other by the ornamentation of the antennula. A possible confusion in previous descriptions of Aristeidae larvae is addressed and a new key for the identification of Dendrobranchiata larvae provided.

Modeling the spatiotemporal distribution of the deep-sea shrimp Aristeus antennatus (Crustacea: Decapoda) on the northwestern Mediterranean continental margin crossed by submarine canyons

Abstract Submarine canyons aggregate numerous marine species and can affect the structure of benthic communities. However, analyses dedicated to assess the spatial distribution variability among several canyons are rare. In the northwestern Mediterranean Sea, three major submarine canyons consecutively indent the narrow margin. There, the abundance of deep-sea blue and red shrimp Aristeus antennatus (Crustacea: Decapoda), one of the most important fishery-targeted species in the western and central Mediterranean Sea, sustains relatively high incomes for the nearest fishing harbors. To date, the spatial distribution of this shrimp species has only been assessed on known fishing grounds, but it has neither been modeled simultaneously covering several submarine canyons nor according to the environmental conditions. In this study, we aimed to look over the spatiotemporal shrimp distribution in a region of the northwestern Mediterranean Sea with a particular interest in variations in the three submarine canyons. From summer landing data between 2005 and 2014, we implemented a species distribution model with georeferenced catches linked to environmental data of the shrimp habitats. The model showed that the bottom topography was one of the most essential variables to explain the spatial distribution of the catches and that the highest catch rates were between 475 m and 575 m depth. Overall, two canyons (Blanes and Palamos) sheltered high estimates of catches on the shallow and narrow part of their margins (at 510 and 565 m depth). Among them, 60% of estimated summer catches came from the Palamos Canyon, but this estimate shifted to the Blanes Canyon in summer 2008, probably due to variations in fishing fleet behavior. Modeled hypothetical temperature changes scenarios (to 1 °C warmer than the average) suggested the shrimp catches would decrease less in the Blanes Canyon (3% fewer catches than the average) than in the Palamos Canyon (20% fewer catches than the average). The information produced by the species distribution model allowed setting spawning locations and depths, which is useful to better understand the canyon influence on benthic communities and to parameterize larval transport models.

Genetic structure and population connectivity of the blue and red shrimp Aristeus antennatus

The blue and red shrimp Aristeus antennatus is a demersal marine species harvested by bottom trawling in the Mediterranean Sea, the adjacent Atlantic Ocean (AO) waters, and the Mozambique Channel in the Indian Ocean (IO). As it is considered to be a priority species for sustainable fishing, identification of its genetic stocks and the connectivity between them is essential. Using 12 microsatellite loci we detected at least four genetic stocks distributed in the Western Mediterranean (WM), Eastern Mediterranean (EM), AO, and IO and signals for a possible fifth stock in the Alborán Sea. We detected no additional population structuring within the WM. Thus, although the Almería-Orán Front exerts some isolating effect, high genetic homogeneity and gene flow are present within the WM Basin. The IO stock is genetically closer to the AO stock than to the others; thus, the species dispersion route is more likely via the Atlantic Ocean than via the Red Sea. Large effective population sizes suggest population sustainability, but moderate genetic diversity values indicate to proceed with caution. Our genetic results serve as a basis for species conservation to ensure long-term sustainability of this marine resource.

Morphological identification and molecular confirmation of the deep-sea blue and red shrimp Aristeus antennatus larvae.

The early life stages of the blue and red shrimp Aristeus antennatus (Decapoda: Dendrobranchiata: Penaeoidea: Aristeidae) were described by Heldt in 1955 based on plankton samples, larval rearing and assumptions of species habitat. Even with adequate keys, identification of its first larval stages remained a difficult task due to the lack of specific morphological characters which would differentiate them from other Penaeoidea species. Larvae of Aristeus antennatus were collected in the continental slope off the Spanish Mediterranean coast in August 2016 with a neuston net and preserved in ethanol 96%. DNA from the larvae was extracted and the molecular markers Cytochrome Oxidase I and 16S rDNA were sequenced and compared to that of adults with the objective of confirming the previous morphological description. Then, we present additional information to the morphological description of Aristeus antennatus larval stages through scanning electron microscopy and molecular analysis. This represents the first documented occurrence of Aristeus antennatus larvae off the Catalan coast and sets the grounds for further work on larval ecology and population connectivity of the species, which is an important contribution to a more sustainable fishery.

Total mercury levels in crustacean species from Italian fishery

ABSTRACTThis study investigated mercury contamination levels in eight commercially valuable crustacean species caught off the Central Adriatic and Tyrrhenian coasts of Italy. Total mercury levels were measured by Thermal Decomposition-Amalgamation-Atomic Absorption Spectrophotometry. Results showed a high variability among species with values ranging from 0.070 to 1.24 (mg kg−1 wet weight). The lowest mercury levels were detected in caramote prawn (Penaeus kerathurus), warty crab (Eriphia verrucosa) and European spider crab (Maja squinado), decapods living in shallow waters. Levels exceeding the limits established by the European Commission were found in species living in close contact with bottom sediments: deepwater rose shrimp (Parapenaeus longirostris), blue and red shrimp (Aristeus antennatus) and Norway lobster (Nephrops norvegicus). For shrimps, the inter-individual variability observed was mostly related to the body size, indicating the accumulation of mercury with age. An estimation of the human intake of mercury associated to the consumption of the crustaceans sampled and its comparison with the Tolerable Weekly Intake are provided.

Improving codend selectivity in the fishery of the deep-sea red shrimp &lt;em&gt;Aristeus antennatus&lt;/em&gt; in the northwestern Mediterranean Sea

The deep-sea red shrimp Aristeus antennatus is one of the most valuable demersal resources in Catalonia (northeast Spain), and Palamós is the most important harbour for this fishery in the area. Here, a management plan published in 2013 established the use of a 40-mm square-mesh codend (40s), replacing the previously used 50-mm diamond mesh codend (50d). The objective was to decrease the amount of juveniles in the catches, but the regulation did not bring the expected results. In this study, we measured and compared the selectivity of the 40s and the 50d in this fishery. In addition, we experimented with the use of a 50-mm square-mesh codend (50s). According to our results, the 40s had a lower 50% selection length (L50) than the 50d, while the 50s had a substantially higher L50 than the other two. A transition analysis showed an increase in yield per recruit after the second year from a hypothetical implementation of the 50s. Our conclusion is that the 40s does not have a higher selectivity than the 50d, which (at least partially) explains the failure to reach the management objective in Palamós. Conversely, the use of a 50s would significantly benefit the fishery, increasing gear selectivity and yield per recruit.

Long-term climatic influences on the physiological condition of the red shrimp Aristeus antennatus in the Western Mediterranean Sea

CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 72:111-127 (2017) - DOI: https://doi.org/10.3354/cr01453 Long-term climatic influences on the physiological condition of the red shrimp Aristeus antennatus in the Western Mediterranean Sea Ana Carbonell1,*, Pere Joan Llompart2, Magdalena Gaza1, Arnau Mir2, Alberto Aparicio-González1, Diego Álvarez-Barastegui3, Rosa Balbín1, Joan Enric Cartes4 1Instituto Español de Oceanografía, Centro Oceanográfico de Baleares, Muelle de Poniente s/n, 07015 Palma de Mallorca, Islas Baleares, Spain 2Universitat de les Illes Balears, Carretera de Valldemossa, km 7.5. 07122 Palma de Mallorca, Islas Baleares, Spain 3SOCIB, Balearic Islands Coastal Observing and Forecasting System, Parc Bit, Norte, Bloc A 2op., pta. 3, 07121 Palma de Mallorca, Islas Baleares, Spain 4Institut de Cièncias del Mar (CMIMA_CSIC), Psg. Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain *Corresponding author: ana.carbonell@ba.ieo.es ABSTRACT: Changes in the physiological condition (represented by Kn = body weight/length-predicted weight) of the deep-sea shrimp Aristeus antennatus associated with the warming and rising salinity trends in the western Mediterranean were analyzed to explore how deep-sea populations can reconfigure their biology to match the changes in ocean conditions. Two slope areas around the Balearic Islands (Western Mediterranean Sea) were analyzed using sampling data and generalized additive models. The 23 yr time series of monthly Kn estimates shows 2 different aspects of the life history of A. antennatus, corresponding to 2 different seasonal periods. The Kn series from June through September reflects the shrimps’ reproductive condition to the north of the Islands, while samples from October through May represent a period of low gonad weight and high hepatosomatic indices to the south of the Islands. Oceanographic variables used to construct models and seek relationships with changes in Kn were salinity, temperature, and dissolved oxygen in the Levantine Intermediate Water and Western Mediterranean Deep Water layers, and chlorophyll a satellite imagery data. The North Atlantic Oscillation and the Eastern Atlantic index were used as climatic indicators. Physiologic condition during the winter fattening periods decreased over the time series and was negatively correlated with increasing salinity. During the summer reproductive periods, the best-fitting models show a year-on-year effect and a significant probability of effects on condition from oligotrophication. These results suggest that increasing salinity at depth, which ultimately increases oligotrophy, may cause changes in physiological condition. KEY WORDS: Aristeus antennatus · Physiological condition · Time series · Fisheries · Climate change · Western Mediterranean Full text in pdf format PreviousNextCite this article as: Carbonell A, Llompart PJ, Gaza M, Mir A and others (2017) Long-term climatic influences on the physiological condition of the red shrimp Aristeus antennatus in the Western Mediterranean Sea. Clim Res 72:111-127. https://doi.org/10.3354/cr01453 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 72, No. 2. Online publication date: May 18, 2017 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2017 Inter-Research.

Development and characterization of novel microsatellite markers by Next Generation Sequencing for the blue and red shrimp Aristeus antennatus

Development and characterization of novel microsatellite markers by Next Generation Sequencing for the blue and red shrimp Aristeus antennatus

Condition and recruitment of Aristeus antennatus at great depths (to 2300 m) in the Mediterranean: environmental links and implications for management.

XIX Iberian Symposium on Marine Biology Studies (SIEBM), 5-9 September 2016, Porto, Portugal

Spatial and temporal variation of seasonal synchrony in the deep-sea shrimp Aristeus antennatus in the Western Mediterranean

Resolving drivers of spatial synchrony in marine species is fundamental for the management and conservation of deep-sea ecosystems. Here we examine an 11-year data set of monthly catches per unit of effort (CPUE) of the red-shrimp Aristeus antennatus. These data comprise 16 locations of two population subunits in the Western Mediterranean, the Catalan coast and the Balearic archipelago. The analysis of their seasonal covariation and its space–time structure showed small-scale geographical segregation of locations linked with the seasonal fluctuations of CPUE. Results further revealed that seasonal synchrony dominates at short spatial scales (ca. 50km), while asynchrony prevails are broader spatial scales (ca. 200–300km). This spatial pattern, however, varied over the period examined, although it was specific for each population subunit suggesting contrasting drivers of seasonal synchrony. The Balearic Islands, a patchier population subunit, displayed a seasonal synchrony pattern mainly dependent on biological and oceanographic processes at local scales. By contrast, in the Catalan coast, the pattern appeared related with regional-scale climate, which triggers spatial differences in the phenology of primary producers and the timing of food advection to the seabed. These cascading processes depicted by our investigation shed light on underlying mechanisms shaping the temporal synchrony of broadly distributed deep-sea populations.

Analysis and standardization of landings per unit effort of red shrimp &lt;em&gt;Aristeus antennatus&lt;/em&gt; from the trawl fleet of Barcelona (NW Mediterranean)

Monthly landings and effort data from the Barcelona trawl fleet (NW Mediterranean) were selected to analyse and standardize the landings per unit effort (LPUE) of the red shrimp ( Aristeus antennatus ) using generalized additive models. The dataset covers a span of 15 years (1994-2008) and consists of a broad spectrum of predictors: fleet-dependent (e.g. number of trips performed by vessels and their technical characteristics, such as the gross registered tonnage), temporal (inter- and intra-annual variability), environmental (North Atlantic Oscillation [NAO] index) and economic (red shrimp and fuel prices) variables. All predictors individually have an impact on LPUE, though some of them lose their predictive power when considered jointly. That is the case of the NAO index. Our results show that six variables from the whole set can be incorporated into a global model with a total explained deviance (ED) of 43%. We found that the most important variables were effort-related predictors (trips, tonnage, and groups) with a total ED of 20.58%, followed by temporal variables, with an ED of 13.12%, and finally the red shrimp price as an economic predictor with an ED of 9.30%. Taken individually, the main contributing variable was the inter-annual variability (ED=12.40%). This high ED value suggests that many factors correlated with inter-annual variability, such as environmental factors (the NAO in specific years) and fuel price, could in turn affect LPUE variability. The standardized LPUE index with the effort variability removed was found to be similar to the fishery-independent abundance index derived from the MEDITS programme.

Larval stages of crustacean species of interest for conservation and fishing exploitation in the western Mediterranean

Decapod crustaceans are the main target species of deep water bottom trawl fisheries in the western Mediterranean. Despite their importance for fisheries and conservation, little is known about their larval development, especially in the case of deep water species. In this paper we present new information on the occurrence and morphology of larval stages for some species of commercial interest based on samples collected off the Balearic Islands. Mesozooplankton sampling was carried out using depth-stratified sampling devices at two stations located on the continental shelf break and middle slope, in the northwest and south of Mallorca in late autumn 2009 and summer 2010. We describe in detail the second mysis stage of the red shrimp Aristeus antennatus , not previously known, and the first larval stage of the slipper lobster Scyllarides latus , poorly described almost a hundred years ago. We also report the second finding of larvae of the spider crab Maja squinado and the first capture from the field of larval stages of the rose shrimp Parapenaeus longirostris and slipper lobster in the Mediterranean.