Sciaena Umbra Research Articles

Effects of ambient and boat noise on hearing and communication in three fish species living in a marine protected area (Miramare, Italy)

The WWF-Natural Marine Reserve of Miramare (Trieste, Italy) is located in a major industrial and vacation area in the Adriatic Sea. Consequently, noise emanating from boating and shipping is an inevitable factor for local fishes. This study investigates the effects of ambient and ship noise on representatives of three vocal fish families with different hearing abilities. Ambient and ship noise were recorded, their sound pressure levels measured and played back in the lab. Auditory sensitivity was determined in Chromis chromis, Sciaena umbra and Gobius cruentatus, utilizing the auditory evoked potential recording technique. Compared to lab conditions, hearing thresholds determined during ambient noise playbacks were barely masked. Contrary, the noise emanating from a cabin-cruiser substantially reduced auditory sensitivity relative to thresholds in ambient noise. This masking effect was most pronounced in the frequency range where acoustic communication takes place. Boat noise potentially affects acoustic communication in fishes inhabiting the reserve.

EFFECT OF SOME COATING SOLUTIONS ON THE QUALITY OF VACUUM-PACKED FISH FILLETS

This study was carried out to examine the effect of dip treatment of different coatings of lactic acid, acetic acid, acetic + lactic, chitosan, lactic + chitosan or acetic + chitosan on the shelf life of vacuum-packed lout fish (Sciaena umbra) during chill storage assessed by chemical, microbiological and sensory parameters. The results revealed that the coated fillets presented a remarkable and significant reduction in thiobarbituric acid number “TBA” values compared to control samples during chill storage. In all coating treatments, the TBA values were found to be within the safe limit (35-40 mg) throughout the storage period. Trimethylamine “TMA” in the tested samples showed significant differences between all groups during storage period especially between the coated and uncoated control fillets. In this study, only the uncoated control samples reached spoilage limit after 16 days of storage; meanwhile all other coated samples were within the acceptable limit throughout the whole storage period. Moreover, it was obvious to notice that the most effective treatment was chitosan + acetic followed by chitosan + lactic and then chitosan. The use of chitosan +acetic and vacuum-packaging was found to be very efficient in extending the shelf life of fish fillets samples in the sensory point of view. Thus, vacuum-packaging in conjunction with a chitosan + acetic coating can be used safely to extend the shelf life of fish fillets up to 28 days at 4°C (±1).

Effects of habitat on spillover from marine protected areas to artisanal fisheries

Marine protected areas (MPAs) potentially enhance the long-term sustainability of coastal fish resources that have been overexploited. The types and quality of habitats, both inside and outside the MPAs, may determine the likelihood of migration by fish to surrounding unprotected areas where spillover to fisheries occurs. We assessed whether MPAs enhanced catches of artisanal fisheries, using an experimental fishing study with the same fishing gear as that used by local fishers. This approach allowed us to test the hypothesis of increased catches along the borders of MPAs in comparison with those in other fishing grounds located at medium and far distances from 3 Medi- terranean MPAs: Tabarca Marine Reserve, Carry-le-Rouet Marine Reserve and Cerbere-Banyuls Marine Reserve. Surveys were done over 2 homogeneous habitats (Posidonia oceanica meadow and sand), in 3 different seasons. Catches were significantly higher for some species near the borders of the MPAs when fishing on P. oceanica meadows, but not when fishing on sandy bottoms. The spillover effect appears to be limited by a lack of continuous suitable habitat through the boundaries of the MPA. Some of the species that showed a significant response to protection and concurrent higher catches near the MPA borders, such as Dentex dentex, Mullus surmuletus, Phycis phycis, Sciaena umbra and Scorpaena porcus, are target species of artisanal fisheries. Although we found that the spatial scale of the spillover-induced density gradient was localized, it was sufficient to provide local benefits to artisanal fisheries. We conclude that spillover effects are not a universal consequence of siting MPAs in temperate waters and that they are related to the distribution of habi- tats inside and around MPAs.

Age, growth, sexual maturity and food composition ofSciaena umbrain the south-eastern Black Sea, Turkey

Summary Studied were the age, growth, maturity and food composition of the brown meager, Sciaena umbra, caught off Trabzon, south-eastern Black Sea (Turkey) in 2002–2003. A total of 329 individuals was collected by spear fishing and hand nets. The thin sectioning method was used for aging the fish otoliths. Fitted von Bertalanffy growth parameters for all fish were: L¥ = 51.14 (±1.19) cm, k = 0.27 (±0.02) year )1 and t0 = )0.93 (±0.07) year. This study revealed that S. umbra is a relatively slow-growing and longlived species with a life span in excess of 18 years. Sexual maturity begins when they reach a length of about 15 cm. Lengths at which 50% of brown meagre become mature are 19.50 for males and about 22 cm for females. Spawning begins in June, when the temperature is approximately 18� C, and ends in August. Gut content analysis indicated that this species feeds mainly on crustaceans, then switches to fish as they grow. Sciaena umbra appears to be an apex predator in the upper littoral zone.

Historical Development and Future Projection of Aquaculturein the Black Sea Region

Aquaculture in the Black Sea Region is initiated in inland water with rainbow trout in 1972. Sea cage farms in the region are founded in 1990’s years purposed to grow out of rainbow trout, sea bass and sea bream. Recently sea trout and turbot are lunched to sector. Mussel, brown meagre, sturgeon and mullet species are considering as potential species. In this study, foundation and development of all fish farms in the region were evaluated and investigated historical development thoroughly. Also a future projection was made for region. Data utilized in this study are derived from records of Ministry of Agriculture and Rural Affair and collected field study. There are 10 sea cage farms in the Black Sea Region and their trout production capacity is total 3500 tons/year and sea bass production capacity is total 750 tons/year. The number of inland farms is about 500 with 12000 tons /year overall capacity. Somewhat apart, carp is produced in 8 farms with about overall 40 tons/year. Even thought small fluctuation has been observed year by year, it is estimated that aquaculture production of Black Sea region will be reach about 29000 tons/year in 2030. Recent years, willing of new farms construction and increase of the present farms capacities with 35 years aquaculture production experience, development of aquaculture sector with environmental friendly will increase the productivity and diversity of sources of income, and additionally economic and social development in the region.

Reproductive biology of the vulnerable species <i>Sciaena umbra</i> Linnaeus, 1758 (Pisces: Sciaenidae)

Reproductive biology of the brown meagre, Sciaena umbra , is described based on 171 specimens caught by trammel nets and spear gun from April 1998 to October 2000. Histological examination and gonadosomatic index suggest that the spawning season of the brown meagre in Balearic waters is from May to August and peaks in May and June. Seven stages of gonadal development were identified: immature, early developing, late developing, running, spent, recovering and resting. The frequency distribution of oocyte diameter reveals that brown meagre is an iteroparous, gonochoristic, seasonal multiple-spawning fish with aynchronous oocyte development. Size at first maturity was 25.4 cm of total length for males and 29.9 cm for females. Sex ratio varied with fish size, with a tendency for greater numbers of females in higher size classes. Weight-length relationships for both sexes, as well as for the total population, were significantly allometric positive. An analysis of the monthly variations of hepatosomatic index (HSI), and Le Cren’s condition factor showed that HSI is not a good indicator of the lipid reserves of S. umbra . According to our results, current management measures for this species should be re-evaluated.

Age and growth of brown meagreSciaena umbra(Sciaenidae) in the Adriatic Sea

Age and growth of the brown meagre Sciaena umbra (Sciaenidae) collected (n = 532) in the north-western Adriatic Sea was studied by means of transverse otolith sections. The maximum age estimated was 19 and 16 years for males and females, respectively. The length at age estimated for each sex indicated that females attain a larger size and grow slightly faster than males. Both marginal increment analysis and edge analysis confirmed that annuli are formed once a year, with opaque zones laid down in summer (June-July). Age readings were very precise, with a percentage agreement of 98% between readers and low values of the index of average percent error (0.9%) and coefficient of variation (1.3%). Von Bertalanffy growth function was fitted to age-length data, and growth parameters were estimated for males (L∞ = 44.9 cm; k = 0.27,t0 = −2.17 years) and females (L∞ = 47.2 cm; k = 0.28, t0 = -1.82 years). In both sexes of brown meagre, growth rate was high until they attain 2–3 years of age, i.e. at sexual maturity. Most of catches were obtained in late summer-early autumn. On the basis of present data, the sampled population of brown meagre mostly consisted of small fish younger than three years of age (about 90%). In addition, landings of this species in recent years largely decreased. As reported elsewhere in north-western Mediterranean, brown meagre stock in the Adriatic Sea showed clear signs of depletion, thus specific management measures for this species are urgently required.

CHARACTERIZATION OF SMALL-BOAT NOISES COMPARED WITH THE CHORUS OF SCIAENA UMBRA (SCIAENIDAE)

The WWF-Natural Marine Reserve of Miramare is an urban Marine Protected Area located at 8 km from the seaport of Trieste (North Adriatic Sea, Italy) and very close to a small tourist port. It is inhabited by several hundreds of individuals of brown meagre (Sciaena umbra, Sciaenidae), a sonic fish, whose sounds are made by broadband pulses of short duration with a frequency typically never exceeding 1,200 Hz. During the summer, S. umbra generates at night overlapping sounds called chorus (Bonacito, unpublished data). Despite being protected by the reserve, S. umbra lives in a loud underwater acoustic environment as a result of small-boat passages. This study aims at assessing the relationship between boat noise and S. umbra vocalization.

HEARING UNDER AMBIENT AND SHIP NOISE CONDITIONS: A CASE STUDY ON FISHES FROM A PROTECTED AREA IN THE ADRIATIC SEA

Anthropogenic noise emanating from ship and boat traffic causes growing concerns because it might hinder acoustic orientation and communication in vocalizing fish species. The Miramare Marine Natural Reserve is located in a coastal area of the Gulf of Trieste (North Adriatic Sea, Italy) characterized by considerable commercial and recreational boat traffic. Noise emanating from this source is an inevitable factor for fishes living in this reserve. The present work aims to understand to what degree ambient noise and recreational boat noises affect the auditory sensitivity and, subsequently, acoustic communication of two local vocal species, the damselfish Chromis chromis (Pomacentridae) and the drum Sciaena umbra (Sciaenidae).

Temporal trends of littoral fishes at deep Posidonia oceanica seagrass meadows in a temperate coastal zone

Seasonal abundance and biomass of littoral fish at Posidonia oceanica seagrass meadows were characterized throughout an annual cycle in Mediterranean waters. Bimonthly beam trawl hauls were performed between 18 and 38 m depth at 4 sites sampling from 2 locations. Approximately 8230 littoral fish were collected belonging to 25 families and 51 species with Labridae and Sparidae families being predominant in terms of abundance. Mean fish abundance was 92 ± 7.5 individuals · 1000 m − 2 peaking in March, April and September and total abundance showed significant statistical differences between May and October. Densities of Diplodus annularis, Gobius sp., Mullus surmuletus, Parablennius tentacularis, Sarpa salpa, Sciaena umbra, Scorpaena porcus, Serranus cabrilla, Symphodus ocellatus, Symphodus rostratus, Symphodus tinca and Synodus saurus differed significantly between seasons. Total community biomass varied significantly along the year with maximum values observed in July (1500 g · 1000 m − 2 ) and minimum biomass recorded in October. The number of species ranged between 5 in January and 21 in July while the total number of individuals was 293 in July and 21 in September, and Margalef diversity index differed between 4.11 in July and 1.3 in January. Biomass peaked in summer linked mainly to the increase of S. porcus, Serranus scriba and some Symphodus species. Diversity was maximal in July and the larger mean size for most of the fish species was achieved from May to July corresponding to the recruitment peaks of some of the fish species. The SIMPER analysis showed that there are seasonal differences in the trophic roles of the fish communities at seagrass meadows. The temporal patterns observed highlight the multifunctional role of deep seagrass meadows during the summer months when all the measured parameters are maximal. Those observations point out the need for conservation measures to be intensified in the warm season.

First data on growth of cultured brown meagre Sciaena umbra using diets with different protein and fat contents

Brown meagre Sciaena umbra Linnaeus 1758 is a demersal species living at depths of 0–200 m with a wide distribution in the Mediterranean Sea, Black Sea and eastern Atlantic Ocean. It exhibits nocturnal behavior and occupies bottom caves and seabeds covered with vegetation. This study presents the first data on brown meagre growth under culture conditions and contributes some basic information on its dietary, protein requirement by feeding isoenergetic diets with different protein-lipid ratios by means of self-feeders. Fish with 78.8±15.8 g (mean±standard deviation) body weight were divided into four groups and subjected to four different feeding regimes with three replications for 77 days. In the first group, fish were supplied with a high protein and low fat diet (HPLF, 52∶8 w/w fat-protein ratio), the second one a medium protein and medium fat diet (MPMF, 42∶14), the third with a low protein and high fat diet (LPHF, 31∶23). In the fourth group, fish had access to both HPLF and LPHF diets. Fish fed on HPLF and MPMF diets showed significantly better growth and feed conversion ratios than fish fed on the LPHF diet. Fish with access to HPLF and LPHF diets exhibited comparable growth to the HPLF group but their feed conversion ratio was significantly higher. The condition factor and hepatosomatic index revealed no significant differences between dietary regimes. The liver of brown meagre may serve as a depository organ for energy, judging from its relatively high lipid content (39–43%).

Measurement of alkaline and earthy ions in fish otolith and sea water using a high performance ion chromatography

Fish growth and the relation between growth and environmental conditions offer a good opportunity for measuring alkaline and earthy ions in fish otoliths. The analytical method must involve high sensitivity when attempting to discriminate between fish growth and environmental conditions. The aim of this paper is to propose a chromatographic method, with low detection limits, as a new approach in determining some important micronutrients present in sea water and fish otoliths. The work samples are: coastal, off-shore and sediment waters and fish otoliths ( Engraulis encrasicholus, Mullus barbatus, Umbrina cirrhosa, Sciaena umbra, Pagellus erythrinus) in the Adriatic Sea and the Canal of Sicily. The analytical method includes an IONPAC CS12A chromatographic column and a 18 mM methanesulfonic acid eluent. The detection limit readings obtained with this method, for one E. encrasicholus fish otolith, weighing 2.6 mg are equal or inferior to 0.1 μg/L for lithium (Li), 59 μg/L for sodium (Na), 46 μg/L for ammonium (NH 4), 23 μg/L for potassium (K), 13 μg/L for magnesium (Mg), 88 μg/L for manganese (Mn), 2.567 μg/L for calcium (Ca) and 13 μg/L for strontium (Sr). The HPIC method minimizes overlaps such as Na on Li, and NH 4 in seawater and Ca on Mg and Sr in fish otolith. These elements are an essential constituent present in otoliths when describing the relation between growth and environmental conditions. Good separation among analytes is achieved within 16 min.

Spatial variation and ontogenic shifts in the isotopic composition of Mediterranean littoral fishes

Stable carbon and nitrogen isotope signatures have been determined for littoral fishes from three localities in the Balearic Islands (NW Mediterranean) for trophic assessment. Variation in the isotopic composition was examined at multiple levels: the individual organism, individual populations (ontogenetic variation) and at area effects (different islands). Cluster analyses based on δ13C and δ15N resulted in two very different dendrograms for the fish assemblages from Menorca and Formentera. In both schemes, congeners of the genera Diplodus and Labrus did not cluster together, suggesting that closely related species do not necessarily feed on similar foods. Significant differences in δ15N were detected between locations for Scorpaena porcus, Scorpaena scrofa and Sciaena umbra, and significant differences in δ13C were detected for Scorpaena porcus and Scorpaena scrofa. Overall there were significant spatial differences in the trophic position of littoral fishes among the three Balearic Islands, and fishes from Palma, Mallorca tended to feed at a higher trophic level than fishes from either Menorca and Formentera. Large-scale geographic comparisons, using earlier data from three sites in western Mallorca and in Corsica revealed that throughout the western Mediterranean generally, the average trophic level of fishes differs remarkably little. However, large discrepancies were observed in δ15N for individual species, notably Scorpaena porcus, D. annularis, D. vulgaris and Serranus scriba. 13C composition of fishes did not seem to change greatly among the locations, although marked discrepancies were observed for D. puntazzo and Mullus surmuletus. Given the large-scale patterns we have observed, it is possible that the extent of multichannel omnivory which has been purported to exist in complex aquatic systems, may have been greatly overstated. Regression of δ15N and δ13C with fish body size revealed clear and significant trends for some species. In particular, δ15N appeared to increase with body length in the macrocarnivorous fishes Scorpaena porcus, Scorpaena scrofa, Serranus scriba and Sciaena umbra. Trends were less apparent in animals which feed primarily on small benthic invertebrates, notably the four Diplodus species (D. vulgaris, D. sargus, D. annularis, D. puntazzo), and the labrids Labrus viridis and L. merula.

Indicator species analysis as a test of non-random distribution of species in the context of marine protected areas

Species are identified as bioindicators when their presence or abundance within sites of a particular habitat or a conservation area are high. Dufrêne and Legendre (1997), Ecological Monographs 67: 345–366, proposed the use of a flexible asymmetrical approach to detect indicator species and species assemblages characterizing groups of sites, the indicator value for each species being subsequently tested by randomization. Although the advantages of these methods in comparison to other multivariate or two-way indicator species analyses have been demonstrated, relatively few ecological studies have made use of them. The aim of the present study was to demonstrate the advantages of the indicator species test using a data set generated by traditional fisheries activities at four areas in the Bonifacio Strait Marine Reserve, Corsica, France. ANOVA, Kruskal-Wallis and another randomization test were also performed on the same data set. Of the 54 species caught in the fishing nets, the indicator species analyses identified 19 species for which the indicator value was significant for a given area, whereas the a posteriori Tukey test for ANOVA detected only 12 species for which the mass capture per unit effort was significantly greater for a given area. The efficiency of this new approach within the framework of conservation and marine reserve studies is demonstrated by focusing on three species (Sciaena umbra, Palinurus elephas and Maja verrucosa).

Contribution to the knowledge of species of the genus Stephanostomum Looss, 1899 (Digenea: Acanthocolpidae) from teleosts of the Western Mediterranean, with the description of S. gaidropsari n. sp.

Four species of the acanthocolpid genus Stephanostomum are redescribed from the digestive tract of teleosts in the Western Mediterranean: the type-species, S. cesticillum from Lophius piscatorius is described with a ventrally interrupted ring of 35 circum-oral spines and as lacking a uroproct; S. bicoronatum from Sciaena umbra has a ventrally interrupted ring of 31 circum-oral spines and a uroproct; S. pristis from Phycis phycis has an uninterrupted ring of 36 oral spines and no uroproct; S. minutum from Uranoscopus scaber has an uninterrupted ring of 36 oral spines and a uroproct. A new species, S. gaidropsari from Gaidropsarus mediterraneus, is described with an uninterrupted ring of 36 oral spines and an apparent uroproct. It differs from all other Stephanostomum species with similar oral spine numbers in the armament of the ejaculatory duct, and from various of these species by vitelline distribution, length of the genital atrium, oesophageal length and sucker-ratio.

Development of a sensitive diagnostic assay for fish nervous necrosis virus based on RT‐PCR plus nested PCR

A polymerase chain reaction (PCR)‐based assay to detect nervous necrosis virus (NNV) in fish was developed by using two sets of primers designed on a highly conserved region of the coat protein gene encoded by RNA2 of NNV. The first pair of primers amplified a fragment of 605 bp by one‐step reverse‐transcription (RT)‐PCR, while the second pair amplified an internal segment of 255 bp by nested PCR. Addition of nested PCR increased the assay sensitivity 100‐fold when carried out in a separate tube (two‐step assay) and 10‐fold when performed in the same tube (one‐step assay). The sensitivity of the two‐step assay was 104 times higher than that of virus cultivation. Nested PCR served also to confirm the specificity of the first amplification, as verified also by Southern hybridization analysis and direct sequencing. In species known to be susceptible to infection, such as European sea bass, Dicentrarchus labrax, and gilthead seabream, Sparus aurata, NNV was often detectable in brain tissue by RT‐PCR alone but only by the two‐step assay in blood, sperm, ovarian tissue or larvae. The same was true for sperm and ovarian tissue of shi drum, Umbrina cirrosa. NNV was also detected in the brains of Japanese red seabream, Pagrus major and brown meagre, Sciaena umbra, suggesting that these species can also be infected. No NNV was detected in samples of Artemia salina nauplii and rotifers obtained from a fish farm with an NNV outbreak. The inclusion of nested PCR in the assay appears to be necessary to screen out NNV‐positive broodfish by blood sampling and testing of their larval progeny.

Three rare and little known cryptogonimid digeneans from the sciaenid fish Sciaena umbra (L.) in the western Mediterranean

Three species of cryptogonimid digeneans are redescribed from the gut of Sciaena umbra off Corsica. The systematics of the three species, Metadena pauli (Vlassenko, 1931), Paracryptogonimus aloysiae (Stossich, 1885) n. comb. and Anoiktostoma coronatum (Wagener, 1852), are discussed. The latter two species, which have not been reported for more than 100 years, have previously been confused and synonymised with each other. P. aloysiae, which is transferred to Paracryptogonimus from Anoiktostoma, is restricted to the rectum, whereas A. coronatum prefers the pyloric caeca and anterior intestine.

Spatio-temporal structure of the communities of helminths in the digestive tract of Sciaena umbra L. 1758 (Teleostei).

The helminth community in the digestive tract of the sedentary predatory fish, Sciaena umbra, near the Scandola Nature Reserve, Corsica, consists of 5 species of digeneans. Anoiktostoma coronatum (in the rectum) and Metadena pauli (in the intestine) were found in almost all the fish, and in high numbers; they are considered core species. Distomum aloysiae, Pleorchis polyorchis (both in the intestine), and Stephanostomum bicoronatum (in the rectum) were relatively uncommon, usually found in small numbers, and are considered satellite species. The two core species were very abundant in June, when the size of their populations was strongly correlated with the size of the host fish. At this time, M. pauli was found mainly in the duodenum, but in high populations was spread throughout the intestine (s. strict.). Both species were much less abundant in October, their populations were less dependent on host size, and M. pauli was more limited to the anterior intestine. Pleorchis polyorchis and Distomum aloysiae were more frequent in October, were found predominantly in fish with few M. pauli, and were found posterior to M. pauli, suggesting some interactions between these species. Stephanostomum bicoronatum showed no seasonal patterns, and no apparent interactions with A. coronatum.