Palinurus Elephas Research Articles

Exploration of the inter‐annual variability and multi‐scale environmental drivers of European spiny lobster, Palinurus elephas (Decapoda: Palinuridae) settlement in the NW Mediterranean

AbstractDetermining the drivers of key ecological processes of commercial marine species is important to acquire basic and essential knowledge for fisheries management and conservation. Here we report on a long‐term monitoring of the settlement of the European spiny lobster, Palinurus elephas, the most commercially important spiny lobster species in the Mediterranean and north‐eastern Atlantic. Densities of recently settled individuals (early benthic juveniles – EBJs) were recorded annually, as an approximation to annual settlement, from 2000 to 2016 (17 years) in three zones of the north‐western Mediterranean: Catalonia (CAT), the Columbretes Islands (COL), and the Balearic Islands (BAL). Settlement, the end point that integrate most of the variability occurred during dispersion, is a complex ecological process governed by the interaction of biotic and abiotic factors that can be in turn influenced by the atmospheric and oceanographic conditions. Using linear regression of the size structure of EBJs, we demonstrate that settlement occurs synchronously in the three study zones. Densities of EBJs were handled as time series, and regression analysis revealed that CAT and COL covaried significantly, but none of them with BAL. Therefore, CAT and COL were analysed together using generalized linear model and much of their joint variability was explained by the mesoscale oceanographic index IDEA. Settlement in BAL showed a different pattern, explained by the joint effect of the atmospheric oscillations NAO and WEMO. Complexity of P. elephas settlement cannot be fully accounted neither for CAT‐COL nor for BAL because settlement seems be driven by more complex unknown multi‐factorial processes. Therefore, further studies are necessary to gain insight into other factors that allow short‐ or medium‐term predictions of settlement. Expanding the study area across the Mediterranean would also allow establishing a complete knowledge of the ecology of the species applicable to the management of the fishery.

Marine lobsters in ancient Greek and Latin

This paper describes the Ancient Greek and Latin terminology for marine lobsters, especially for ‘European lobster, Homarus gammarus L.’, ‘common spiny Lobster, Palinurus elephas Fabricius’ and ‘No...

New Data on the Biology and Fisheries of the Threatened Palinurus elephas (Fabricius, 1787) (Decapoda, Achelata, Palinuridae) from the North-West Aegean Sea, Greece

The European spiny lobster Palinurus elephas is a vulnerable species that inhabits and is harvested in the Mediterranean Sea and the adjacent Atlantic waters. The fisheries associated with the spiny lobster are mainly conducted with tangle nets, trammel nets, pots, and creels. The fishing pressure has greatly reduced their numbers, changing them from a common shallow coastal species to a largely remnant population. The relative research on the species’ biology and fisheries from the eastern Mediterranean Sea is almost absent. The fishery along the Chalkidiki Peninsula, Greece, is multispecies, and fishing is conducted by a small number of artisanal fishermen mainly using trammel nets. The lobster stock—both spiny and clawed lobsters—declined significantly during the late 1980s and early 1990s, later than most cases in the Mediterranean Sea. However, data regarding the nature and status of the fishery associated with the spiny lobster in Greece are lacking. Data regarding the characteristics of the spiny regional fishery were obtained by interviews and questionnaires. Additionally, fishery surveys were conducted during the main lobster fishing season from 1 May 2017 to 31 August 2017. Sixteen species were identified (15 finfish species and one invertebrate species) as targeted. In total, 79 spiny lobsters were sampled in this study; the population’s sex ratio significantly diverts from the theoretical 1:1 (χ2 = 4.57; p < 0.05), and males were dominant. Both male and female individuals demonstrate negative allometric growth profiles. In addition, no significant differences were observed between sexes. In Greece, thus far, the knowledge and information are sporadic, limited, and/or species-specific, most of which regard finfish fisheries. Furthermore, the national legislation is rather complicated—or too generalized—thus creating great uncertainties. The in-depth knowledge and experience of fishermen should be further acknowledged and utilized, and wider collaborations among scientists, practitioners, and policy-makers should be established. The present study poses some thoughts on the effectiveness of the recent EU Landing Obligation and its contribution to the potential restoration of the species.

Identification and characterization of trammel net métiers: A case study from the southwestern Sicily (Central Mediterranean)

The high variability of trammel fisheries, due to a marked seasonality in target species and fishing activities needs to be investigated with high spatial and temporal resolution. The present study focuses on trammel net fishery in southwestern Sicily (central Mediterranean Sea) identifying and characterizing the main métiers in relation to some key aspects of the fishery such as the target species, composition of landings, main fishing grounds and time of the year. For this purpose, a multivariate statistical approach based on landings and effort data of the Mazara del Vallo southwestern Sicily, Italy) trammel fleet in the period 2009–2013 was applied. A total of 153 different landed species and four different trammel net métiers were identified. These métiers showed differences in target species (i.e. Sepia officinalis, Palinurus elephas, Mullus surmuletus and a mix of species), fishing season, fishing grounds and dimension of fishing vessels. The métiers identified were significantly different in terms of total average landing per unit of effort (LPUE) with métier 1 targeting M. surmuletus, showing the highest average LPUE (2047 (192 s.e.) g*(h)−1*103 m net) and métier 2 targeting S. officinalis, exhibiting the lowest value (1175 (119 s.e.) g*(h)−1*103 m net).The study provides new knowledge on the dynamics of trammel fisheries in southwestern Sicily also showing that the complex nature of this peculiar fishery should be taken into account in any future sampling program aimed at the monitoring and management of artisanal fisheries in this area and more in general in the Mediterranean Sea.

Ontogenetic trophic segregation between two threatened smooth-hound sharks in the Central Mediterranean Sea

Elasmobranchs are among the species most threatened by overfishing and a large body of evidence reports their decline around the world. As they are large predators occupying the highest levels of marine food webs, their removal can alter the trophic web dynamic through predatory release effects and trophic cascade. Suitable management of threatened shark species requires a good understanding of their behaviour and feeding ecology. In this study we provide one of the first assessments of the trophic ecology of the “vulnerable” smooth-hounds Mustelus mustelus and M. punctulatus in the Central Mediterranean Sea, based on stomach contents and stable isotope analyses. Ontogenetic diet changes were addressed by comparing the feeding habits of three groups of individuals: juveniles, maturing and adults. Our results highlighted that the two species share a similar diet based mostly on the consumption of benthic crustaceans (e.g. hermit crabs). Their trophic level increases during ontogeny, with adults increasing their consumption of large-sized crustaceans (e.g. Calappa granulata, Palinurus elephas), cephalopods (e.g. Octopus vulgaris) and fish (e.g. Trachurus trachurus). Our results provide also evidence of ontogenetic shifts in diet for both species showing a progressive reduction of interspecific trophic overlap during growth. The results of this study contribute to improve the current knowledge on the trophic ecology of these two threatened sharks in the Strait of Sicily, thus providing a better understanding of their role in the food web.

A Typical Mediterranean Fishery and an Iconic Species: focus on the common Spiny Lobster (Palinurus elephas, Fabricius, 1787) in Corsica

The common spiny lobster (Palinurus elephas, Fabricius, 1787) is an iconic species of the Mediterranean Sea. Despite the existence of data on the artisanal fishery of P. elephas in the Mediterranean Sea and particularly in Corsica, knowledge on the biology and life history traits of this iconic species is still lacking. This paper identifies the main gaps in current knowledge and suggests future directions of research to answer these fundamental questions, which are currently unanswered.

Spiny lobster sounds can be detectable over kilometres underwater

The detection ranges of broadband sounds produced by marine invertebrates are not known. To address this deficiency, a linear array of hydrophones was built in a shallow water area to experimentally investigate the propagation features of the sounds from various sizes of European spiny lobsters (Palinurus elephas), recorded between 0.5 and 100 m from the animals. The peak-to-peak source levels (SL, measured at one meter from the animals) varied significantly with body size, the largest spiny lobsters producing SL up to 167 dB re 1 µPa2. The sound propagation and its attenuation with the distance were quantified using the array. This permitted estimation of the detection ranges of spiny lobster sounds. Under the high ambient noise conditions recorded in this study, the sounds propagated between 5 and 410 m for the smallest and largest spiny lobsters, respectively. Considering lower ambient noise levels and different realistic propagation conditions, spiny lobster sounds can be detectable up to several kilometres away from the animals, with sounds from the largest individuals propagating over 3 km. Our results demonstrate that sounds produced by P. elephas can be utilized in passive acoustic programs to monitor and survey this vulnerable species at kilometre scale in coastal waters.

Historical translocations and stocking alter the genetic structure of a Mediterranean lobster fishery.

Stocking is often used to supplement wild populations that are overexploited or have collapsed, yet it is unclear how this affects the genetic diversity of marine invertebrate populations. During the 1970s, a lobster stock enhancement program was carried out around the island of Corsica in the Mediterranean using individuals translocated from the Atlantic coast of France. This included the release of thousands of hatchery‐reared postlarval lobsters and several adult individuals, but no monitoring plan was established to assess whether these animals survived and recruited to the population. In this study, we sampled European lobster (Homarus gammarus) individuals caught around Corsica and tested whether they showed Atlantic ancestry. Due to a natural marked phylogeographic break between Atlantic and Mediterranean lobsters, we hypothesized that lobsters with dominant (>0.50) Atlantic ancestry were descended from historical stocking releases. Twenty Corsican lobsters were genotyped at 79 single nucleotide polymorphisms, and assignment analysis showed that the majority (13) had dominant Atlantic ancestry. This suggests that the hatchery stocking program carried out in Corsica during the 1970s, using individuals translocated from the Atlantic coast of France, has likely augmented local recruitment but at a cost of altering the genetic structure of the Corsican lobster population.

Influence of light, food and predator presence on the activity pattern of the European spiny lobster Palinurus elephas: An investigation using tri-axial accelerometers

Abstract The knowledge of the activity pattern of marine organisms represents a crucial aspect in the studies on their ecology. In this paper, we used for the first time data from tri-axial accelerometers to provide an accurate description of the activity pattern of the European spiny lobster, Palinurus elephas. Sixteen lobsters (8 males, 8 females) were tagged with tri-axial accelerometers in order to monitor their activity in a mesocosm during four replicate trials. In each trial the lobsters were submitted to three treatments of the duration of one day each: exploration, presence of food and presence of a predator. The variance of roll body angle (VariRoll) was chosen among a number of available variables as a proxy of lobster activity during each treatment. The lobsters were more active during the night and in low-light hours than during the day. Moreover, they were i) more active without food or predator, ii) less active in the presence of a predator, iii) with an intermediate activity level (i.e. values of VariRoll) in the presence of food. Besides contributing to the knowledge of P. elephas ecology, the results of this study provide a new analytical method to describe activity patterns in slow-moving animals.

Propagation distances and sound properties of the antennal rasps produced by spiny lobsters (Palinurus elephas) in European coastal waters

Spiny lobsters (Palinurus elephas) have been overfished in European waters, and adult breeders are now scarce. Our recent study highlighted the high acoustic potential of this species, which can emit loud broadband pulse trains, called “antennal rasps,” with peak-to-peak source levels (estimated at 1 m from the source) above 160 dB re 1 μPa² [Jezequel et al., Marine Ecology Progress Series 615 (2019)]. These acoustic properties imply that these sounds could be detected during in situ passive acoustic monitoring. However, before using a such tool, we need to understand how antennal rasps propagate in situ and at what distance they could be detected above the ambient noise. To answer these questions, we recorded spiny lobster antennal rasps in the Iroise Sea (Brittany, France). We used a linear array of 8 hydrophones, with distances between animals and receivers ranging from 0.5 m to 100 m. We recorded antennal rasps from 38 individuals of various sizes. Our results demonstrate that large spiny lobsters can be detected at 100 m, and that sound properties might be directly influenced by the size of the individuals.

European spiny lobster recovery from overfishing enhanced through active restocking in Fully Protected Areas

Fully protected areas (FPAs) help preserving biodiversity and reversing the global decline of fishery resources. Stocks of the European spiny lobster Palinurus elephas (Fabr. 1787), among the most precious gourmet seafood worldwide, are currently facing a dramatic decline. Previous attempts of recovery based on fishery restrictions or active post-larval restocking in marine reserves provided unsuccessful outcomes. Here we present results of a 5-year restocking program carried through a Collaborative Fishery Research (CFR) project, in three ad-hoc established FPAs replenished using below-legal size wild juveniles. Results showed that Catch per Unit Effort (CPUE) in terms of both density and biomass burst (by ca. 300–700%) just 2 years since FPAs establishment, regardless of location. We also report tangible spillover effects (ca. 30–50% increase in density and biomass CPUE outside the FPAs) by the end of the program. Data from a 15-years lasting monitoring of a pilot FPA established in 1998, where the restocking protocol was conducted and protection kept in force once restocking ceased, demonstrated the persistence in time of restocking’ benefits. We foster that creation of FPAs assisted with local restocking under oriented CFR programs can represent an option for the recovery of European spiny lobster stocks from overfishing.

Revisiting the bioacoustics of European spiny lobsters Palinurus elephas: comparison of antennal rasps in tanks and in situ

Revisiting the bioacoustics of European spiny lobsters Palinurus elephas: comparison of antennal rasps in tanks and in situ

Homing and home range of the European spiny lobster, Palinurus elephas (Decapoda, Palinuridae) acoustically tracked

Abstract A specific study has been carried out for the first time to investigate the homing capability and daily home range of the spiny lobster Palinurus elephas by means of ultrasonic telemetry. Nine lobsters collected in the Capo Gallo — Isola delle Femmine marine protected area (northwestern Sicily, central Mediterranean) were tagged with miniaturized transmitters and released at a single site inside the protected area. The lobsters were monitored with the purpose of calculating their horizontal and vertical positions, analysing their movement patterns to assess their homing capability, and calculating their daily home range. Five lobsters moved back close to the capture sites within the first 20 hours after release (‘homed’). The remaining four lobsters ‘relocated’ to a different refuge. Homed lobsters had a larger home range than relocated lobsters. This study provides the first description of a homing pattern with high spatial resolution in the wild European spiny lobster as inferred by ultrasonic telemetry.

The use of 3-axial accelerometers to evaluate sound production in European spiny lobster, Palinurus elephas

The European spiny lobster Palinurus elephas emits sound (“rasp”), moving the base of their antennas, as response to the presence of predator and for interspecific communication. During the last decade, three-axial accelerometers have been used to mainly describe diel activity patterns, circadian rhythms and rate of energy consumption of different lobster species, but these devices can also record sound emission in terms of mechanical vibration of carapace. In order to evaluate the efficiency of accelerometers in recording sound production (rasp events and number of pulses inside each rasp) and in discriminating of that from other behavioural events, accelerometers were used in combination with hydrophone and during mesocosm free ranging conditions. Three-axial accelerometers were able to detect sound production events in P. elephas. All the rasp events (n = 405) recorded with hydrophones were also detected by the accelerometers considering its data sampled at different frequency (from 800 Hz to 12 Hz). However, the detection of the number of pulses within each rasp sound decreased with sampling frequency of accelerometer data (median of predictive error for 800 Hz = 0.33; median of predictive error for 12 Hz = 0.65). During mesocosm free condition, three behavioural categories were identified: walk, tail flip, and rasp, the last with averaged (15.16 ± 3.52 m/s2) and maximum (29.49 ± 9.37 m/s2) values of acceleration significantly higher than the other two. Findings from this study prove that accelerometers register only lobster body vibrations providing a clear signal that is not distorted by other noises in the environment. They also allowed to identify rasps for each tagged lobster, something not possible using hydrophones in both, aquaria or natural habitat. Accelerometer resulted an useful tool to detect behaviours even with low mobility species. Moreover, the possibility to couple accelerometer and other biologging techniques would help to improve our understanding of the behaviour of a large range of free-living species.

A histological atlas for the Palinuridae (Crustacea: Decapoda: Achelata): A guide to parasite discovery and spotting the abnormal in spiny lobsters.

Crustaceans suffer from diseases that can alter their survival and ecology with additional economic consequences for fisheries and aquaculture. Many parasites have been described from crustaceans and with the advent of novel technologies such as next generation sequencing, the discovery of novel parasites has become increasingly efficient. Molecular techniques are beginning to surpass more conventional tools for parasite discovery, but they typically do not provide information on pathology. Histopathology remains one of the least expensive methods for parasite discovery and allows for both detection of parasites and descriptions of the pathology they cause. When used in concert with modern molecular and electron microscopy techniques, the approach is powerful; however, there are few informational tools for the interpretation of histological slides from crustaceans. Those available do not provide comprehensive images of all organs and early works were limited to lower resolution than currently available. More recent texts provide in-depth details of infection in histological section, but few provide images of healthy material or describe a baseline from which to compare. Here, we provide a series of image plates derived from histologically processed tissues from three palinurid lobsters: Panulirus argus, Palinurus elephas and Panulirus guttatus. Histology from these lobsters shows high visual similarity in all tissue types. We provide a histological atlas of healthy tissue that can be used as a baseline resource for pathobiologists working on these common species (and related crustaceans) and we discuss how disease may result in visual aberrations to these tissues.

Copper sorption on chitin and acid-washed shrimp shells from Palinurus elephas: isotherm and kinetic studies

The removal of toxic heavy metals species from aqueous solutions is the concern of this paper which investigates the sorption kinetics and equilibriums in the uptake of copper(II) by low-cost chitinous adsorbents prepared from Algerian shrimp (Palinurus elephas) shell waste. Acid-washed shrimp shells and chitin biosorbents resulted from the bulk treatment of the waste with 1.2 M HCl and 1 M NaOH that aims to the demineralization and the deproteinization of raw biomass. Elements analysis experiments showed that such treatments led to a significant increase in nitrogen content in the biomaterial. In fact, this finding proved that nitrogen chemical moieties (amine and acetamide) are likely the key parameters in copper(II)-binding phenomena. Maximum adsorption yields at pH 4 were found to be 16 mg g−1 for acid-washed shrimp shells and 24 mg g−1 for chitin but many times more with chitosan (about 150 mg g−1). Besides, kinetic measurements of copper(II) sorption onto the various biomaterials were fitted properly to the pseudo-second-order model and the Langmuir equation applied to the isotherms modeling.

Comparing the catch composition, profitability and discard survival from different trammel net designs targeting common spiny lobster (Palinurus elephas) in a Mediterranean fishery.

In the Balearic Islands, different trammel net designs have been adopted to promote fisheries sustainability and reduce discards. Here, we compare the catch performance of three trammel net designs targeting the spiny lobster Palinurus elephas in terms of biomass, species composition and revenue from commercial catches and discards. Designs differ in the netting fiber type (standard polyfilament, PMF, or a new polyethylene multi-monofilament, MMF) and the use of a guarding net or greca, a mesh piece intended to reduce discards. Catches were surveyed by an on-board observer from 1,550 netting walls corresponding to 70 nets. The number of marketable species captured indicated that the lobster trammel net fishery has multiple targets, which contribute significantly to the total revenue. The discarded species ranged from habitat-forming species to elasmobranches, but the magnitude of gear-habitat interactions on the long term dynamics of benthos remains unclear. No relevant differences in revenue and weight of discards were detected after Bayesian analyses. However, the species composition of discards was different when using greca. Interestingly, high immediate survival was found for discarded undersized lobsters, while a seven day survival assessment, using captive observation, gave an asymptotic estimate of survival probability as 0.64 (95% CI [0.54–0.76]). Therefore, it is recommended that it would be beneficial for this stock if an exemption from the EU landing obligation regulation was sought for undersized lobsters in the Balearic trammel net fishery.

Linking home ranges to protected area size: The case study of the Mediterranean Sea

Protected areas not allowing extractive activities (here called fully protected area) are a spatially explicit conservation management tool commonly used to ensure populations persistence. This is achieved when an adequate fraction of a species' population spends most of its time within the boundaries of the protected area. Within a marine context, home ranges represent a tractable metric to provide guidance and evaluation of fully protected areas. We compiled peer-reviewed literature specific to the home ranges of finfishes and invertebrates of ecological and/or commercial importance in the Mediterranean Sea, and related this to the size of 184 Mediterranean fully protected areas. We also investigated the influence of fully protected areas size on fish density in contrast to fished areas with respect to home ranges. Home range estimations were available for 11 species (10 fishes and 1 lobster). The European spiny lobster Palinurus elephas had the smallest home range (0.0039 ± 0.0014 km2; mean ± 1 SE), while the painted comber Serranus scriba (1.1075 ± 0.2040 km2) had the largest. Approximately 25% of Mediterranean fully protected areas are larger than 2 times the size of the largest home range recorded. Fish densities were significantly higher when fully protected areas were larger than the home range, while no change in density occurred when home ranges were larger than fully protected areas. These results display a direct link between the effectiveness of fully protected areas and species' home range, suggesting that fully protected areas of at least 3.6 km2 may increase the density of local populations of these coastal marine species.

Modeling the Dispersal of Spiny Lobster (Palinurus elephas) Larvae: Implications for Future Fisheries Management and Conservation Measures

Knowledge of larval dispersal, population dynamics and connectivity in relation to the management and conservation of commercially important species is vital if existing fisheries are to remain sustainable into the future. Larval dispersal of the commercially exploited spiny lobster, Palinurus elephas, was modelled from Marine Protected Areas located in the southwest of England for a 16-month period using a General Individuals Transport Model (GITM). The model included physical particle advection based on current fields from a 3D hydrodynamics model and a larval behaviour module. Our results demonstrate the overall dispersal patterns of P. elephas larvae and highlight populations capable of self-seeding and those which are seemingly reliant on larvae from more distant populations. The results indicate where further research may be required to fully understand how populations of P. elephas are maintained at regional, national and international scales while providing us with the opportunity to discuss the effectiveness of current approaches to conservation and fisheries management.

Oxidative stability of the hemolymph in different crustacean species

The aim of this study was to determine interspecies and gender differences in the lipid metabolism and hemolymph oxidation stability in intermoult period of the European spider crab (M. squinado), the warty crab (E. verrucosa) and the European spiny lobster (P. elephas). In hemolymph samples activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and paraoxonase 1 (PON 1), as well as hemolymph cholesterol, triacylglycerol and non-esterified fatty acid (NEFA) concentrations were determined. The hemolymph of M. squinado showed the highest levels of SOD activity, cholesterol and triacylglycerol and the lowest levels of PON 1 activity compared to values determined in the hemolymph of E. verrucosa and P. elephas. Gender differences were determined only in M. squinado samples. Males had significantly higher activity of PON 1 and lower NEFA values compared to females. M. squinado hemolymph lipid metabolism and oxidation stability in intermoult period could be attributed to their biological, metabolic characteristics and environmental conditions in which these species live.