Background. Poor selectivity of trawl cod-ends has been a major problem of the modern-day fisheries, contributing to destruction of non-target organisms. It is expected thatincreased trawl selectivity can reduce bycatch and discards. This would only be true if significant numbers of the escaping fishes survive. The chances of survival of many species after escaping the trawl cod-end are still poorly known. This study was aimed at providing mortality estimates of brown comber, Serranus hepatus, escaping from two different demersal trawl cod-ends (40 mm diamond and square) in the Aegean Sea. We also looked at possible seasonal variation in the survival rate of escaped brown comber (diamond mesh). Materials and Methods. Two experiments were conducted off the Yassica Island, Izmir Bay (Aegean Sea, Turkish coast): in winter 2007 and summer 2008. Five hauls were performed in winter (January–February 2007), and nine hauls in late summer (September 2008). Sampling time was 15 min, except for a control cage in 2007 experiments. Results. No significant difference in the mortality of brown comber for 40 mm diamond mesh cod-end was demonstrated between the winter (2.2 percentage points) and the summer (1.9 percentage points). Throughout each period of this experiment, the survival of escaping brown comber showed a length-dependent mortality, with the majority of dead fish being less than 8.8 and 9.4 cm in length for diamond and square test cages, respectively. The experiments carried out in 2008 demonstrated that the survival of brown comber for diamond and square test cages was generally very high (98.1% and 82.9%, respectively). Conclusion. The escape mortality of brown comber was negligible for two different cod-ends and seasons

In 2007–2008 the pink salmon, Oncorhynchus gorbuscha, was observed to attempt spawning migration up the Revelva River. The possibility of natural spawning of this alien species in rivers and lakes of Spitsbergen, as well as the risk of its natural hybridization with the native Arctic charr, Salvelinus alpinus, are discussed

Background. Organochlorine pesticides (OCPs), which act in a similar way to natural hormones, lead to disorders of the endocrine system in animals and humans (endocrine disruptors). Among food products, fish are considered to be the main source of these compounds in the human diet, posing a health risk to consumers. The aim of this study was to determine concentrations in fish and their environment of certain organochlorine pesticides in fish and their environment and to estimate daily intakes (EDI) of individual pesticides from the fish examined. Materials and Methods. Analyses aimed at detecting the pesticides (OCPs: a-, b-, g-HCH, heptachlor, heptachlor epoxide, aldrin, dieldrin, and endrin) included samples of water taken from the lower stretch of the Oder River and three fish species, which are commonly harvested in that area. Quantitative analyses were carried out using the Capillary Gas Chromatography/Mass Spectrometry method in a GC MSD HP 6890/5973 apparatus. Results. The study found that concentrations of OCPs in fish gonads were significantly higher than in the muscle tissue. The dominant pesticide compound in gonads of roach and bream was g-HCH, whilst b-HCH predominated in the muscle tissues of those fishes. Endrin, on the other hand was the major pesticide in the muscle tissue of ide. Mean concentrations of OCPs in the gonads ranged from 0.385 to 0.544 ng· g–1 wet weight (w.w.) for a-HCH, 0.745 to 0.832 ng· g–1 w.w. for g-HCH, 0.479 to 0.576 ng· g–1 w.w. for dieldrin, and 0.381 to 0.684 ng· g–1 w.w. for endrin. Concentrations of the studied compounds in the water taken from the Oder River followed the order: endrin > g-HCH > a-HCH > dieldrin > b-HCH > heptachlor ˜ aldrin > heptachlor epoxide. The highest log BCF was obtained for fish gonads and ranged from 1.5 (endrin) to 3.4 (heptachlor epoxide). Estimated daily intakes (EDI) varied from 0.0014% to 0.097% of the acceptable daily intake (ADI). Conclusion. This study revealed no direct risk linked to the consumption of fish captured from the study area. However, from the ecological aspect, the accumulation of organochlorine residues in fish gonads has been considered a dangerous phenomenon, as this may result in decreased reproduction of fish and other aquatic organisms, potentially leading to their extinction

One specimen of lancet fish,Notoscopelus kroyeri(Malm, 1861), was collected in March 2007 by commercial bottom trawl in the Aegean Sea. This record consists the easternmost record of lancet fish in the Mediterranean Sea. Morphometric and meristic characteristics of this species are given.

Background. Assessments of the efficacy of anaesthetics are usually based on observations of fish behaviour or changes in blood parameters. In this study we attempted to assess the process of anaesthesia, caused by 2-phenoxyethanol and Propiscin (0.2% etomidate), based on recording the heartbeat and the respiratory frequency. Materials and Methods. The effect of two concentrations of 2-phenoxyethanol (0.4 mL·L–1 and 0.8 mL·L–1) and two concentrations of Propiscin (1.0 mL·L–1 and 2.0 mL·L–1) on heartbeat and respiratory frequency of common carp, Cyprinus carpio L., were studied using ECG. Concurrently, during general anaesthesia, the fish behaviour was also observed. Results. The anaesthetic potential of 2-phenoxyethanol and Propiscin at the applied concentrations was comparable. The behavioural reactions caused by the agents were not identical. At the beginning of the exposure, 2-phenoxyethanol produced locomotor agitation and an irritation-like reaction of the respiratory system. Propiscin had no such effect. Both agents induced a decrease in the ventilatory and cardiac frequencies. The reductions caused by Propiscin were simultaneous. The inhibitory effect of 2-phenoxyethanol at the concentration of 0.8 mL·L–1 was much stronger on respiration than on heart rate. Conclusion. The ECG method can be an important and objective tool supplementing data acquired during visual observation of responses to anaesthesia. Its major advantage is the comparativeness of data.

Background. Various compounds are being used as immuno-stimulants in various aquaculture feed types but the importance of their prolonged use is at present unknown. It is also true for those intended to modify trout susceptibility to white spot disease caused by Ichthyophthirius multifiliis. The immuno-modulating effects on rainbow trout of short- and long-term feeding using dry feed with inclusion of beta-glucan (0.2%) have therefore been evaluated. Materials and Methods. The immune reactivity was assessed by measuring susceptibility to I.multifiliisinfections and plasma lysozyme in the host, factors which are considered innate response parameters. Rainbow trout, Oncorhynchus mykiss(Walbaum, 1792) (Actinopterygii: Salmoniformes: Salmonidae),were fed (control feed or glucan-containing feed) for 14 or 35 days before challenge (exposure to infective I. multifiliis theronts) and the resulting infection (number of trophonts in the skin) was recorded on day 11 post-exposure to theronts. Results. All fish obtained infection following parasite exposure but glucan-fed fish showed a lower infection at day 46 compared to fish fed control-feed. The lysozyme activity of fish plasma was evaluated throughout the experimental period and found slightly but significantly increased in association with glucan-feeding at day 14, 17, and 46. Conclusion. No evidence for an exhaustion of these selected innate response parameters due to prolonged glucan-feeding could be detected within the experimental period of 46 days.

A specimen of Facciola’s sorcerer,Facciolella oxyrhyncha(Bellotti, 1883), was caught for the first time in the central Aegean Sea, on January 2007 by a commercial bottom trawler at a depth of about 230 m on the muddy bottom of Southern Sigacik Bay, Aegean Sea, Turkey.

Background. Even thoughSerranus cabrilla has been aby-catch species in trawling operations, it is now becoming an economically important fish species on the Turkish Coast of Aegean Sea, because of its low market price. For an efficient fisheries management of the stocks it is important to know important biological parameters of the commercially exploited species. Therefore the aim of this study was to obtain necessary growth- and reproductive characteristics of comber representing the local population of this fish in the study area. Materials and Methods. Biological aspects of comber were examined based on a total of 1452 specimens collected from the Aegean Sea, during the period January 2005–December 2005.Age of fish was determined by otolith reading. Length–weight relation and the von Bertalanffy equationwere used to evaluate the fish growth. Results. Annuli on otoliths indicated the presence of 6 age classes. The computed growth parameters were: L8 = 23.88 cm; k = 0.298 year–1 and to = –1.577 year. The length–weight relations were calculated as: W= 0.0111· L2.998 for sex combined. The growth performance index (F') was 2.230. The fish mature sexually for the first time at a total length of 13.20 cm (L50). The spawning season of comber was from March to May, with a peak in April. Conclusion. The comber grows rapidly attaining almost 75% of its linear growth during the first two years of life and then the growth slows down. The growth coefficient, (k), indicates slow attainment of maximum size because of significantly correlated to temperature of sea water, leading to a considerable variability in the life span between areas.

Background. The examination of morphological features related to feeding in fish, as well as their relation with body length, are of increasing scientific interest. In the present study, information on intestine (gut) morphometrics that appear in the relevant literature has been compiled, analysed, and discussed. Materials and Methods. Search of gut-related bibliography was conducted, using online literature databaseson fish feeding and ecomorphology. The resulted data was tabulated. Relationships between mean, minimum, and maximum relative gut length (RGL) and intestine length weight index (ILW, Zihler’s index), as provided by the original author, with species’ fractional trophic levels (TROPHs; extracted from FishBase) were explored. Finally, using the relations between gut length (GL) and body length (L) provided by the original authors, regressions were reconstructed and compared based on species’ feeding habits and taxonomy. Results. The amount of information related to gut morphometrics referred to 498 species. The relations between GL and L referred to 71 species, but four species were omitted from the analyses. Mean, minimum, and maximum RLGand ILW values were negatively related (for all cases: P < 0.01) with TROPH. The GL–L regressions performed for 67 species revealed the presence of two major groups as herbivorous fishes and carnivorous fishes. Grouping according to species’ taxonomic order did not form any significant groupings. Conclusion. Existing information on intestine morphometrics is generally accumulated in a few scientific papers. All the analyses performed on the compiled data reinforced the pattern generally accepted that herbivores have longer intestines than carnivores. In addition, the influence of species’ evolutionary history on comparisons of gut length between species with different feeding habits was not verified. Finally, equations relating RGL and ILW to TROPH can be used for TROPH value estimates from morphological data that are easy to obtain, especially in the lack of species’ feeding habits data

Background. The Ganga River (Ganges) is known of its rich fish diversity which is adversely affected by degrading environmental and ecological conditions. There are more than 300 exotic fish species in India.Many of them (particularly Cyprinus carpio) escaped from confinement and are now present in the Ganga River, challenging its ecological equilibrium.The aim of this project was to study the population characteristics of Cyprinus carpio (i.e., the abundance, size range, food and feeding, gonado-somatic index (GSI), gonad maturity stage, maturity and breeding) and the altered fishery dynamics. Materials and Methods. The commercially caught fishes, including the exotic ones, were identified, examined and measured. Important indices such as: the abundance index of exotic fishes, the gonado-somatic index (IG), as well as the gonad maturity stage of the escapee C. carpio were determined. The gut content was also analyzed to identify food items and thereafter the food richness, diet breadth, and gut repletion index (GRI%) were calculated using the Simpson’s diversity index. Results. C. carpio introduced about sixty years ago for aquaculture has now been found to invade into the Ganga, the largest river of the country contributing significantly to the fishery. The abundance index of C. carpio ranged from 12.2% to 45.5 % in 250 km long river stretch of the Ganga River flowing along Kanpur to Varanasi in the state of Uttar Pradesh. The gut content analysis revealed the presence of Eichhornia (9.8%), Pistia (11.6%), Nymphaea (8.5%), annelids worms (7.8%), algae (20.2%), mud and detritus (14.8%). The calculated diet breadth ranged from 0.82% to 0.91%; food richness ranged from 12 to 16, and the gut repletion index (GRI%) was 100% at different sampling sites. Mature females represented all the six reproductive stages with varying gonado-somatic index (IG) (0.5 to 30) in different catches. Presence of spent, ripe, and mature females was recorded. Conclusion. Abundance of exotic fish primarily C. carpio and Oreochromis niloticus in the fishery of the Ganga River was observed. The gonado-somatic index (IG) and the presence of all the six gonadal stages confirmed that C. carpio established its breeding population. The dominant catch of exotic fishes negatively impacted on the important indigenous fishes particularly Indian major carps (Catla catla,Labeo rohita,and Cirrhinus mrigala). The change in dynamics of the fishery due to the presence of common carp attracted attention to conserve rich indigenous germplasm facing threats of shifting from their natural habitats

Background. The Siberian sturgeon, Acipenser baeri,is one of the most important sturgeon species cultured in Poland. The effective management of aquaculture production ofthis species requires contemporary knowledge of broodstock structure, mating patterns, and genetic diversity of broodstock. The aim of the present study was the application of microsatellite DNA analysis for estimation of gene diversity in the Siberian sturgeon farmed at a Polish fish farm. Materials and Methods. Fin clips were randomly sampled from 94 specimens of Siberian sturgeon broodstock reared at the Wšsosze Fish Farm near Konin, Poland. The analysed broodstock has been kept there since 1996, with new specimens being introduced annually. The fish were studied in 2007-2008. Genomic DNA for amplification of microsatellite loci was extracted using Chelex 100. Six microsatellite loci (Afu-19, Afu-39,Afu-68,AfuB-68, Spl-163, andSpl-168) were amplified for examination of the genetic variability of the studied fish. Results. Within 94 individuals of the Siberian sturgeon, a total of 74 alleles were detected in six polymorphic microsatellite loci. The number of alleles per locus ranged from 8 to 18, with an average allele number being 12. The genetic diversity of six microsatellite loci varied from 0.686 to 0.811. Conclusion. This technology has great potential for use in aquaculture of sturgeon fish, especially when levels of genetic variation could be monitored and inbreeding controlled in commercial breeding programs.

Following a series of surveys with bottom longlines and fish traps along the island slopes off the archipelagos of Madeira, Canaries and Cape Verde, and with bottom trawls along the coast of Morocco and Western Sahara between 2004 and 2006 many specimens of Synaphobranchus were caught, revealing the presence of two species. Based on these specimens and Museum preserved specimens from this areagrey cutthroat,Synaphobranchus affinis Günther, 1877, is recorded for the first time from off Portugal, Madeira archipelago, Great Meteor Seamount, Canary Islands, Morocco, Western Sahara, Cape Verde Islands, and Senegal. It is confirmed that S. kaupii is also conspecific in this area. Meristic and morphometric data of the specimens studied are also presented

The first records of Lampris guttatus in the Mediterranean Sea date back to 1807. Yet, until now it has been considered as a rare species (less than 25 specimens recorded in the literature). Since 2008, at least 23 specimens have been fished or observed along the French Mediterranean coast. In this paper, we present an updated review of records in the Mediterranean and discuss the possible link with the present sea water warming. We hypothesise that the recent Mediterranean specimens could come from the Atlantic, throughout the Gibraltar Strait, following a northward migration along the Northeast Atlantic coast due to present global warming.

A second record of the small Indo-Pacific fish Tylerius spinosissimus (Tetraodontidae) (known as spiny blaasop) was documented at the beginning of 2009 in the waters of Rhodes Island (south-eastern Aegean Sea, Greece). The finding shows the putative establishment of a population of this alien fish in the Mediterranean with a centre the Dodecanese plateau.

One specimen of the Cadenat’s rockfish,Scorpaena loppeiCadenat, 1943 (Scorpeanidae), was caught off Marmaris (eastern Aegean Sea, Turkey) on 27 December 2008 by bottom trawl net. The specimen was 56.15 mm total length. S. loppei is evidently rare in the Aegean Sea than it is in the western Mediterranean.