Search

In 1990s, the European spiny lobster Palinurus elephas , one of the most commercially important species in the Mediterranean, exhibited a population decline. For this reason, fully protected areas (FPAs) appeared effective in re-establishing natural populations and supporting fishery-management objectives. Here, the reproductive parameters of P. elephas populations in two different FPAs (Su Pallosu and Buggerru, central-western Mediterranean), where a restocking programme was carried out, and in their surrounding commercial zones, were investigated from quantitative and qualitative perspectives. The comparison of fecundity between females collected inside and outside FPAs did not show statistical differences as well as the vitellogenin concentration, which did not vary among eggs of different size classes of females caught inside and outside the FPAs, indicating the same reproductive potential. The study demonstrated a benefit of overexploited populations in terms of enhancement of egg production overtime (15 years for Su Pallosu and 6 years for Buggerru) with a mean egg production 4.25-5.5 times higher at the end of the study than that observed at the beginning of the study. The main driver of eggs production appeared to be size, with larger lobsters more present inside the FPAs than outside. Given these results, the dominant contribution of the two studied FPAs to the regional lobster reproduction is remarkable., Competing Interests: The authors declare no conflict of interest.

Oviducal glands (OGs) are distinct expanded regions of the anterior portion of the oviduct, commonly found in chondrichthyans, which play a key role in the production of the egg in-vestments and in the female sperm storage (FSS). The FSS phenomenon has implications for understanding the reproductive ecology and management of exploited populations, but little information is available on its taxonomic extent. For the first time, mature OGs from three lecithotrophic oviparous and four yolk-sac viviparous species, all considered at risk from the fishing impacts in the central western Mediterranean Sea, were examined using light microscopy. The OG microanatomy, whose morphology is generally conserved in all species, shows differences within the two reproductive modalities. Oviparous species show a more developed baffle zone in respect to viviparous ones because of the production of different egg envelopes produced. Among oviparous species, Raja polystigma and Chimaera monstrosa show presence of sperm, but not sperm storage as observed, instead, in Galeus melastomus and in all the viviparous sharks, which preserve sperm inside of specialized structures in the terminal zone.

Cartilaginous fish are commonly recognized as key species in marine ecosystems for their fundamental ecological role as top predators. Nevertheless, effective management plans for cartilaginous fish are still missing, due to the lack of knowledge on their abundance, distribution or even life-history. In this regard, this paper aims at providing new information on the life-history traits, such as age, maturity, reproductive period, in addition to diet characteristics of eleven rare cartilaginous fish inhabiting the Central-Western Mediterranean Sea belonging to the orders Chimaeriformes ( Chimaera monstrosa ), Hexanchiformes ( Heptranchias perlo and Hexanchus griseus ), Myliobatiformes ( Aetomylaeus bovinus and Myliobatis aquila ), Rajiformes ( Dipturus nidarosiensis and Leucoraja circularis ), Squaliformes ( Centrophorus uyato , Dalatias licha and Oxynotus centrina ) and Torpediniformes ( Tetronarce nobiliana ), useful for their assessment and for future management actions. Particularly, the present paper provides for the first time the age estimation of D. nidarosienis and L. circularis which were both found capable of becoming older than ten years. In addition, the present study updates the sizes of first maturity of C. uyato and D. licha , which appeared to be capable of reproducing earlier than what was previously hypothesized, representing very valuable information for a better understanding of these rare species populations status and, eventually, their conservation. On the basis of the stomach content analysis, it was possible to identify five different predator groups.

Despite being commonly recognized by the general public, knowledge about the biology and life-history of electric rays is still scarce. Globally, according to the International Union for Conservation of Nature, more of the 80% of the species belonging to the Torpedinidae family are, indeed, classified as Data Deficient, so as, in most of the cases, no proper management measures are available for the conservation of these species. For this reason, the main goal of this study is to provide new information on life-history traits of three species inhabiting the Mediterranean Sea. Age and growth were estimated through direct annuli count of 146 vertebral centra sections of Torpedo marmorata. Females' growth pattern was found to be better described by a S-shaped function (Gompertz L ∞ = 622mm TL; k = 0.15; IP=2.75 years), while males' by a logarithmic one (von Bertalanffy L ∞ = 485mm TL; k = 0.14; t 0 = -2.28). The oldest female and male were aged 17 (560mm TL) and 11 (432mm TL), respectively. Females (L 50 =379mm TL and A 50 =5.5 years) appeared to mature later than males (L 50 =272mm TL and A 50 =3.8 years), also attaining bigger sizes. Despite the observation of late-pregnant females being found only in autumn and regressing ones in autumn and winter, the presence of juveniles during the whole year may indicate a longer reproductive period. The stomach content analysis identified T. marmorata as a top predator (TROPH=4.38) with a very narrow trophic niche (Bi=0.22), extremely specialized in feeding on bony fishes. In addition, this work provides new and updated information on T. torpedo and the rare Tetronarce nobiliana growth, reproductive features and diet. Therefore, offering new essential data to assess the population conditions of all Torpedinidae species that inhabit the Mediterranean Sea, will lead to effective conservation plans., (Copyright © 2021 Elsevier GmbH. All rights reserved.)

As far as is known, in this paper the first case of lacking of skin-related structures (epidermis, stratum laxum, dermal denticles and teeth) in a free-swimming elasmobranch, the blackmouth catshark, Galeus melastomus, is reported. The individual was caught by trawl in Sardinian waters (central-western Mediterranean) in July 2019 at a depth of 500 m. Although this kind of morphological abnormality is potentially fatal, the observations suggested that the specimen was in good health and well developed., (© 2020 Fisheries Society of the British Isles.)

Reports of marine litter pollution first appeared in scientific literature of the early 1970s; yet, more than 40 years later, no rigorous estimates exist of the amount of litter existing in the marine environment. To cope with this global urgency, this study reports the status of marine litter abundance along fishing grounds surrounding the island of Sardinia (CW Mediterranean Sea; FAO Geographical Sub-Area 11) through three years of trawl surveys. A total of 302 hauls, covering a total of 18.4 km 2 of trawled surface were carried out in the framework of the MEDITS campaign, at depths comprised between 0 and 800 m. A total of 918 items were collected and sorted, with the highest concentration observed above 200 m depth. Overall, plastic was the dominant component of litter, followed by glass and metal. Comparing our results with other areas from the Mediterranean basin, Sardinian waters showed a lower impact, possibly as a consequence of multiple factors such as the lower human population density and the low flow of the main rivers, among others. In addition, fishermen behaviour with respect to marine litter was investigated by mean of anonymous questionnaires, emphasizing the necessity to further develop management policies and infrastructures supporting litter disposal., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Addition of 100 millimolar KCl, NaCl, or Na(2)SO(4) strongly promoted acidification of the medium by cells of Nicotiana tabacum/gossii in suspension culture. Acidification was greater in the case of NaCl-adapted than in that of wild type cells, and strikingly so in KCl medium when fusicoccin (FC) was present. Back-titration indicated that net proton secretion in KCl medium was increased 4-fold by FC treatment in the case of adapted cells; but was not even doubled in wild type cells. Membrane potential was higher in NaCl-adapted cells. FC treatment hyperpolarized wild, but not NaCl-adapted cells, suggesting a higher degree of coupling between H(+) efflux and K(+) influx in adapted cells; FC enhanced net K(+) uptake in adapted but not in wild cells. Acidification by cells suspended in 10 millimolar KCl was highly sensitive to vanadate, but that after addition of 100 millimolar KCl or NaCl was much less sensitive. Addition of 100 millimolar NaCl to wild type cells already provided with 10 millimolar KCl briefly accelerated, then slowed down the rate of acidification. If the addition was made after acidification had already ceased, alkalization was observed, particularly in the presence of FC. The results are consistent with the operation of a Na(+)-H(+) antiporter.

Stimulation by sodium or potassium chloride of the ABA-induced increase in proline was synergistically enhanced by CaCl(2) or MgCl(2) as well as by 1,3-bis[tris(hydroxymethyl)methylamino] propane chloride (BTP-Cl), N-methyl-d-glucamine chloride (NMG-Cl), or 2-amino-2-hydroxymethyl-1,3-propandiol chloride (TRIS-Cl). This enhancing effect did not depend on the osmolarity and occurred when Cl(-) was higher than K(+) in the incubation medium, but not vice versa. When CaCl(2) or MgCl(2) or NMG-Cl were added, the higher the Cl(-):K(+) ratio in the external solution the higher was the increase in proline. When the excess of Cl(-) to K(+) was obtained with BTP-Cl the highest enhancing effect resulted with a Cl(-):K(+) ratio of 3:1 while, at a 5:1 ratio, the KCl stimulation was completely suppressed. The inhibiting effect of proline accumulation by NH(4) (+) and 4,4'-diisothiocyano-2,2'-disulfonic acid stilbene was reversed to varying degrees depending on the magnitude of the excess of Cl(-) on K(+) concentration in the medium. Also, the inhibition of proline accumulation obtained by tetraethylammonium chloride, monensin, and d-mannose was similarly reverted. These data suggest that Cl(-) elicits an increase in ABA-induced proline which needs the simultaneous presence of K(+) (or Na(+)) to take place.

The increase in proline induced by ABA, a process stimulated by NaCl or KCl in barley leaves, did not occur when Na(+) (or K(+)) was present in the external medium as the gluconate salt, namely with an anion unable to permeate the plasma membrane. However, proline increase was restored, to different extents, by the addition of various chloride salts but not by ammonium chloride. Moreover, it was shown that the stimulation of the process by NaCl (or KCl) was variously affected by the presence of different salts; all the ammonium salts (10 millimolar NH(4) (+) concentration) inhibited this stimulation almost completely. Inhibition by NH(4) (+) was accompanied by a decreased Na(+) influx (-40%). Also, in the case of Na-gluconate, Na(+) uptake was reduced and the addition of Cl(-) as the calcium or magnesium salt (but not as ammonium salt) restored both the ion influxes and the increase in proline typical of NaCl treatments. Both 4,4'-diisothiocyano-2,2'-disulfonic acid stilbene (DIDS), an anion transport inhibitor, and tetraethylammonium chloride (TEA), a K(+) channels-blocking agent, caused, as well as with a reduction of ion influxes, an inhibition of the proline accumulation. The inhibition was practically total with 1 millimolar DIDS and about 80% with 20 millimolar TEA. A possible role of ion influxes in the process leading to the increase in proline induced by ABA is proposed.