Aquatic organisms are exposed and adjust to a wide variety of environmental challenges including natural and anthropogenic factors.Natural sources are understood the effects of temperature, and saline fluctuations, oxygen availability, the relative abundance of chemical elements and pathogenic invasion.On the contrary, anthropogenic factors are considered the availability of heavy metals, the presence of hydrocarbons, industrial and urban wastes, and pesticides.Moreover, these organisms suffer, in order to maintain homeostasis, growth and reproduction, the effect of temporal and spatial variations.All the environmental changes (natural and non-natural) may cause a different degree of stress in aquatic organisms, via induction of disbalance between the generation and elimination of reactive oxygen species and reactive nitrosative species.A brief summary on the actual knowledge on the establishment, by environmental effects, of oxidative/nitrosative stress and the effect on the antioxidant system in marine organisms, is presented in this review to contribute to the deeper understanding of the complexity of the metabolic and physiological changes that aquatic organisms are constantly suffering.
Distribution patterns of live scleractinian coral colonies on vertical faces of concrete blocks were compared with distribution patterns of environmental parameters known to affect coral recruitment and growth. Coral coverage was not random across the blocks and among regions of their faces. Variations in colonization did not correspond to differences in substrate type, illuminance, and water motion intensity. Coral distribution significantly correlated with blocks location and faces orientation, and these correlations depended on prevailing current direction. These correlations and dependencies are consistent with the hypothesis that the coral coverage was detrimentally affected by a low quality of water flow from the local marine port.
Sea bass (Dicentrarchus labrax, Moronidae), European eel (Anguilla anguilla, Anguillidae) and blackspot seabream (Pagellus bogaraveo, Sparidae) were studied to check their mucus, blood sera and tissue samples for antibacterial and agglutinating activity against a variety of Gram negative and positive bacteria. Samples were also examined for their haemolytic properties against sheep red blood cells. The highest antibacterial activity was detected in the blood sera of blackspot seabream and European eel (against Vibrio alginolyticus) and in the kidneys of sea bass (against Photobacterium damselae subsp. piscicida). Haemolytic properties against sheep red blood cells were observed in the mucus of sea bass and blackspot seabream, as well as in the sera of eel and sea bass. The sera of sea bass and eel showed also agglutinating activity against Pseudomonas aeruginosa and Staphylococcus aureus; the mucus of sea bass was able to agglutinate isolates of Vibrio fluvialis, V. alginolyticus and A. hydrophila. The study suggested that the mucus secretions, biological fluids and organs of the examined fish species can be regarded as an interesting source of bioactive compounds with antibacterial and haemolytic properties.
Sparidentex hasta is superior over Acanthopagrus latus in market price and growth rate while A. latus is superior over S. hasta in number of eggs produced, hatching rate, larval survival and eventually number of fry produced. Thus, the possibility of obtaining a hybrid with close resemblance in appearance and growth rate to S. hasta and being superior in fry production resembling A. latus would be an encouraging hybrid to seek as being the aim of this study. The broodstocks used for this study, S. hasta and A. latus, were injected with human chorionic gonadotropin hormone to initiate spawning. The eggs were collected and manually fertilized successfully to produce the following types: A. latus (♀) x A. latus (♂), A. latus (♀) x S. hasta (♂) (Hybrid I), S. hasta (♀) x S. hasta (♂), and S. hasta (♀) x A. latus (♂)(Hybrid II). The larval survival rate at 54 day after hatching of A. latus and Hybrid II was significantly the highest (p 0.05) from Hybrid I fry. The resemblance of hybrid II to S. hasta in body appearance will fetch a better market price while being similar to A. latus in larval survival will imply superiority in fry production. Thus hybrid II would be selected and recommended for further work to evaluate its growth rate to market size fish.
The biological reason for a species' presence under given environmental conditions is that the species possesses traits that make establishment and survival, usually also reproduction, possible under these conditions.Biological traits analysis (BTA), when coupled with environmental variables, can provide information regarding which traits are to be expected for a given environmental state.As such, BTA provides complementary information to multivariate analysis of community data based on species composition.In this study, BTA was conducted on a data set of sediment macrofauna collected from a temperate fjord system and related to a wide range of environmental variables.The biological traits were analysed in a multiple parallel ordination framework, which can enhance the reliability of the extracted gradient structure and evaluate the importance of weight given to abundance.Two traitclines, gradients in functional attributes of the species, were found in the study area.The first traitcline was related to bottom currents and sediment constituents while the second traitcline was related to current strength and particle deposition on the bottom.Together with a companion study of gradients in species composition (coenoclines), this study of functional features (traitclines) illustrates that the species composition may consist of taxonomically different, but functionally similar species, giving rise to strong gradients in species composition but weak gradients in trait category composition when subjected to ordination analyses.
The rare findings of specimens in larval or post-larval stages (6 phyllosomas and 7 nistos/early juveniles) belonging to the family Scyllaridae are reported for the waters around Sicily.Some were stranded on different winter occasions near the Strait of Messina (north-eastern Sicily), while others were collected during experimental trawl surveys carried out in the Sicilian Channel, at depths up to 450 m.All phyllosoma instars were in advanced stages of development; however, the absence of complete morphological references on the larval characteristics of the family Scyllaridae, necessary for distinguishing the different genera (Scyllarus and Scyllarides, small or large slipper lobsters, or the extremely rare Acantharctus) and species inhabiting the Mediterranean, did not allow to attribute the phyllosomas to a specific taxon.On the contrary, apart from one nisto without apparent lobes (maybe belonging to the species Scyllarides latus), nistos/early juveniles could be classified at generic level on the basis of similarities with the morphology of adult antennae, as pertaining to the genus Scyllarus, but the characters of juveniles are in general ineffective to discriminate between Scyllarus arctus and Scyllarus pygmaeus (the only two known Central Mediterranean species); in fact, the small size and the depth at which they settled suggested that some may belong to the smaller, deeper species Scyllarus pygmaeus.
Many vertebrates and invertebrates in the marine environment create and respond to sound. Due to increasing use of waterways, levels of anthropogenic sound are greater than ever. We examined the responses of larvae of temperate invertebrates to three sound treatments: natural ambient sound (shallow rocky reef), anthropogenic sound (an outboard motor) and no sound (control). Sound recordings were played to molluscan, echinoderm and bryozoan larvae in Petri dishes in the laboratory and the movement of swimming larvae was filmed and quantified in two-dimensional space. Larvae of the gastropod Bembicium nanum increased their swimming activity in response to both natural and anthropogenic sound, while larvae of the bryozoan Bugula neritina decreased swimming activity when exposed to boat sounds, but not recordings from the natural reef. Considerable variation was observed in the swimming behavior of larvae of the echinoid Heliocidaris erythrogramma and we did not observe any differences in response among the treatments. The behavior of the oyster Crassostrea gigas was dependent on its nutritional status. Unfed larvae did not respond to sound, whereas fed larvae increased swimming activity, but only in response to natural sound. Hence effects were highly species-specific, with three of the four species showing some response to sound and apparently distinguishing among different sound frequencies. This study adds to the growing body of evidence that sound may be an important behavioral cue. It may justify further research into the use of sound as an antifouling agent or a tool in the restoration of reef species.
The ragworm Hediste diversicolor (O.F. Müller, 1776) plays a key role in the estuarine water-sediment interface.This scientific project comes under the framework of the International network Nereis Park Experiment gathering 27 laboratories from all over the world.The experiments were carried out concurrently in spring 2007 using a common protocol.In the Loire estuary, the samples were collected in the intertidal zone of the Saint-Nazaire Bridge.During the field experiment, we estimated the surface area of the burrow walls (Sb) value varied from Sb = 0.26 m 2 .m - to 2.18 m 2 .m - (mean Sb = 0.75 m 2 .m - ), and the pumping rate (Pr) value from Pr = 0.9 l.d -1 m -2 to 7.7 l.d -1 m -2 (mean value Pr = 2.7 l.d -1 m -2 ).The density and the biomass of H. diversicolor populations largely controlled the amount of reworked sediment.In the laboratory, we estimated the pseudo-diffusive mixing, Db value varied from Db = 1.2 to 1.6 (mean Db = 1.5).The non-local transport (r) from the upper layers to the bottom of the tubes varied from r = 1 to 7.2 (mean r = 4.3).A positive relationship could be established between Db and the temperature while on the contrary a negative relationship could be established between the Db and biomass.It seems that small individuals are more efficient reworkers than big ones.
To increase the knowledge on the biology and the ecology of Caranx caballus (green jack), a dietary analysis was carried out.Stomachs of 271 specimens from the commercial catches of the artisanal fishery along the coasts of Manzanillo, Colima, México from December 2000 to December 2001 were analyzed.Prey items in the stomach contents were identified, counted and weighed, the percentage frequency of occurrence, percentage by number and percentage by weight were calculated.We also determined indices of relative importance, diversity of trophic spectra and feeding.Forty two dietary components from five taxa were apparent: fishes, crustaceans, mollusks, cnidarians and chaetognaths.Percentage weight and volume did not vary throughout the year, and showed a distinct preference for fishes, whereas the numeric index showed a preference for crustaceans followed by fishes, chaetognaths and cnidarians.There was no difference between the diets of females and males.Feeding between green jack size groups changed with development: in terms of weight percentage, small fish fed on crustaceans, medium and large jacks fed on fishes, crustaceans and cnidarians.
The Levantine Basin (LB) is still considered a void as regards its cetacean fauna: species population abundance and distribution patterns are unknown, and even the list of species and their regional status have so far not been finalized.In an effort to fill the knowledge gap, we present original data collected in the LB over the years 1993-2009.The data relies on strandings, bycatch victims and on incidental and dedicated-survey sightings.We supplement these by reviewing available information on cetacean occurrence in the LB, prior to and including the above period.We believe that the following list and suggested status is a comprehensive updated regional inventory: Species with a 'regular' status include the common bottlenose dolphin, striped dolphin, common dolphin, Risso's dolphin and rough-toothed dolphin, as well as Cuvier's beaked whale; 'visitors' include false killer whale, sperm whale, minke whale and fin whale; Indo-Pacific humpback dolphin, humpback whale and killer whale are designated 'vagrants'.The only common Mediterranean species notably absent is the long-finned pilot whale.Indeed, despite its profound oligotrophicity, the diversity of cetacean species in the LB equals that in the western basins, and due to the relatively lower anthropogenic impact that it sustains, it should receive its share of resources and efforts towards conserving this diversity.
The concentrations of copper, zinc, lead and cadmium in the soft parts of Mediterranean mussel Mytilus galloprovincialis caught from the Sinop coasts of the Black Sea have been measured by an atomic absorption spectrophotometer for monitoring metal pollution level in the coastal water seasonally in 2010.In the present study, a statistically significant difference in the concentrations of all metals investigated was observed.The results were compared with previous studies and discussed.It is concluded that the mussels M. galloprovincialis are suitable biomonitors to assess changes in metal pollution in this coastal area of the Black Sea.
First records in the East Atlantic are reported for the North-West Atlantic endemic mysid Neomysis americana (S. I. Smith, 1873), previously known as an invader of South-West Atlantic coasts. Two specimens were caught in 2010 in coastal waters of The Netherlands. The new records provide the first evidence for a west to east transfer of a mysid species across the Atlantic, whereas previously published transfers were observed only in the opposite direction. Major diagnostic characters are reconsidered and the validity of the European species of Neomysis and Acanthomysis is discussed. A pictorial key to these species is given to facilitate future assessments of potential range expansions of N. americana.
Historical data were used to estimate interannual tendencies for the Sea of Oman over the past 50 years. Declining trends were shown for the atmospheric surface level pressure in the region affected by the Siberian High atmospheric anomaly, the zonal component of wind speed, concentration of nitrates, biomass of diatoms and sardine landings. Changes in Zooplankton biomass showed no clear trend. These trends were associated with and accompanied by rising atmospheric temperature, sea surface temperature, annual variability of the kinetic energy of mesoscale eddies, frequency of fish kills (along with the death of other animals- dolphins, turtles, and sea birds) and harmful algal bloom incidents. In terms of interannual coupling between physical and biological processes, the evaluated trends imply that the weakening of the Siberian High atmospheric anomaly results in the decline of the zonal wind speed and a regional increase of air temperature. This in turn increases the temperature in the mixed layer which strengthens thermo-haline stratification of the water column. Increasing stratification prevents the penetration of nutrients into the mixed layer and does not favor the interannual increase of biological productivity, although annual variation of biological productivity has increased, from 1997 to 2008.
The aim of this paper was to describe the distribution of non-specific immune parameters in two fish species considered as new candidates for aquaculture diversification, greater amberjack and blackspot seabream. In particular, haemolysins, haemagglutinins and lysozyme were investigated to monitor their changes induced by two different stressors: 1) an experimental challenge of greater amberjack with the bacterial pathogen Listonella (Vibrio) anguillarum, which simulated an acute stress condition, and 2) a 14-day starvation period in blackspot seabream, which simulated a chronic stress condition. For each experiment, unstressed fish were kept and sacrificed at the same time intervals to be used as controls. In greater amberjack an increase in lysozyme was detected in challenged fish compared to control ones, while haemolytic activity and haemagglutinating titres showed a depressive effect following to the challenge. In blackspot seabream, starvation resulted in a reduction of lysozyme content in the mucus and plasma, as well as of haemolytic activity. The variations measured in non-specific immune parameters suggest their use as indirect markers of stress or altered health conditions.
This study investigated some aspects of stress research, including, also, the effects of chemical anaesthesia, in two important species for diversification in aquaculture, blackspot seabream, Pagellus bogaraveo and greater amberjack, Seriola dumerilii.The first part of the research (trial 1 and 2) was designed to determine the efficacy of clove oil as an anaesthetic alternative to MS-222.In trial 1, the minimum concentration of anaesthetic producing the total loss of muscular tone within 3 min, and recovery within 10 min, was determined.The obtained results showed that MS-222 and clove oil were effective as anaesthetics for juveniles of blackspot sea-bream and greater amberjack at concentrations of 40 and 100 mg L -1 , respectively.The aim of trial 2 was to assess the side-effects of both anaesthetics on greater amberjack juveniles by monitoring serum cortisol and glucose levels, and haematocrit values.No significant differences between anaesthetics were found for most of the measured physiological variables.The second part of research (trial 3) was designed to establish the ability of anaesthesia to mitigate stress responses blocking activation of the HPI axis associated to handling stress.In this trial, the stress responses to handling of adult blackspot sea-bream anaesthetised with either anaesthetics were compared to those of unanaesthetised fish used as controls.Serum cortisol and glucose concentrations were used as stress indicators.Both anaesthetics were unable to block activation of the HPI axis that occurs as a consequence of handling stress in blackspot sea-bream, although anaesthesia with both anaesthetics proved to be effective in reducing the duration of stress response.
Bubble-gum corals (Paragorgia spp.) appear to lack predators common to many other deep-sea corals.The aim of this study was to determine whether compounds from red and white colored bubble-gum coral Paragorgia arborea (Linnaeus, 1758) from different geographical locations inhibit predation or elicit different behavioral responses.We extracted secondary metabolites from red and white colonies of P. arborea, incorporating different concentrations of the compounds into feeding pellets, and offered these to pinfish Lagodon rhomboides (Linnaeus, 1766) in behavioral feeding assays.Red-colored P. arborea produced a lipophilic compound which at high concentrations stimulated defensive responses, however, lipophilic compounds from white coral colonies did not produce significant defensive behavioral responses by fish.Water-soluble and extracted sclerites elicited no behavioral effects from L. rhomboides.
A brief review of investigations carried out at IAMC-CNR Messina on the reproductive biology of farmed blackspot sea bream Pagellus bogaraveo, a new candidate species for aquaculture, is presented.Different aspects of sexuality, including hermaphroditism, gametogenesis, spermatozoal ultrastructure, maturity staging, seasonal development of gonads, and spawning in captivity, were studied.Protandrous hermaphroditism appeared to be the prevalent sexual pattern, although a high incidence of gonochorism occurred.Males were most abundant in smaller size classes and reached sexual maturity at 28.0 cm, while females predominated in the larger size classes and reached maturity at 29.5 cm.The reproductive season lasted from February until April, as in the natural environment.Spontaneous spawning in tank occurred occasionally, whereas approximately 50% of females produced eggs upon stripping.The remaining 50% failed to ovulate, or even to achieve oocyte maturation, indicating an impaired reproductive functionality.A high incidence of oocyte atresia was also recorded.Males produced a small quantity of highly viscous milt, containing only 3% motile spermatozoa.The spermatozoon of P.bogaraveo has an ovoid head, a midpiece containing only one mitochondrion, and a 50.64 ± 4.82 μm long flagellum, inserted perpendicularly and eccentrically into the nucleus.
The ontogenetic development and pattern of main digestive enzyme activities (proteases, carbohydrases and lipases) were investigated in farmed sharpsnout seabream Diplodus puntazzo larvae and juveniles, during the passage from the larval stage to adult (from 21 to 277 days after hatching -DAH).Larvae showed exponential growth, thus confirming that Rotifers and Artemia nauplii are suitable preys for early feeding of D. puntazzo larvae.Pepsin activity was low in the larvae, but it increased afterwards in relation with stomach development.In juveniles, levels of specific activity of trypsin, chymotrypsin and elastase were lower compared to that recorded in larvae.A decrease in the activity of the alkaline proteases could be related to an increase in the functionality of stomach.Qualitative and quantitative assay of glycosidases ( -amylase, cellulase and maltase) showed high glycosidase activity, indicating that D. puntazzo is capable of digesting carbohydrates in its diet.Levels of lipase activity in juveniles were higher than those found in larvae.Our results didn't show an inductive character of lipases, since in juveniles the activity levels were almost constant even if the fat content of compound diet varied (from 7.0 % to 20 %).The rapid changes in the digestive activities of D. puntazzo larvae supported the existence of well established induction and regulation digestive mechanisms.Present results also confirm that D. puntazzo larvae have complete digestive enzymatic equipment that increased during larval ontogeny and enable larvae to digest and absorb nutrients contained in live preys once exogenous feeding occurred.The enzymatic pattern is correlated with omnivorous feeding habits of the species.Moreover, the patterns of activity of the main digestive enzymes of D. puntazzo larvae and juveniles indicated the early functional development of their digestive system and suggested this species as a good candidate for Mediterranean aquaculture using the compound diet.
