Sand Smelt Research Articles

Marmara Denizi’nde Gümüş Balığı (Atherina hepsetus Linnaeus 1758) Avcılığında Kullanılan Uzatma Ağlarının Modifikasyonu ve Av Verimi Üzerine Etkileri

Gümüş balığı; tüketim amaçlı kullanılmanın yanında, İstanbul Boğazı, Çanakkale Boğazı ve çevrelerinde olta ile lüfer avcılığında yem olarak kullanılmaktadır. Gümüş balığı, özellikle lüfer avcılığı döneminde ticari balıkçılar tarafından sade uzatma ağları ile yoğun olarak avlanmaktadır. Bu çalışmada Güney Marmara’da bir balıkçının 2014-2019 yılları arasındaki 2 yıllık periyotlarda gümüş balığı avcılığında kullandığı sade uzatma ağlarının teknik özellikleri ve yıllara göre ağlarında gerçekleştirdiği modifikasyonlar tespit edilmiştir. 2016-2017 yılında 2014-2015 yılına göre ağ göz açıklığı, ip kalınlığı, ağ rengi, ağ yüksekliği, mantar büyüklüğü, ağ uzunluğu; 2018-2019 yılında 2016-2017 yılına göre ip kalınlığı, ağ yüksekliği, ağ uzunluğunda modifikasyonlar yapıldığı belirlenmiştir. Ağlarda gerçekleştirilen modifikasyonlar sonucunda av veriminde 2017-2018 yılında 2016-2017 yılına göre av veriminde 5,79 kat artış olduğu tespit edilmiştir. En yüksek birim av miktarları (BAVM) 2016-2017 yılında 06:00 ile 08:59 saatleri (0.041 adet/m2.operasyon-1) arasında, 2017-2018 yılında ise 09:00 ile 11:59 saatleri (0.175 adet/m2.operasyon-1) arasında tespit edilmiştir. En yüksek BAVM kuş sürüsü avcılık yöntemi (1,309 adet/m2.operasyon-1) ile en düşük BAVM ise rastgele avcılık yöntemi (0.082 adet/m2.operasyon-1) ile belirlenmiştir. 2016-2017 ve 2017-2018 yılında avlanan uzatma ağları ile avlanan gümüş balıklarının ortalama boyları sırasıyla 12,7±0.09 cm, 12,7±0.07 cm; ortalama ağırlığı ise 12,6±0.21 gr, 13,1±0.17 gr olarak hesaplanmıştır. Bu çalışmada Atherina hepsetus’un uzatma ağları ile avcılığı ilk kez tanımlanmıştır. Hedeflenen bir türün avcılığında etkin bir şekilde kullanılan uzatma ağlarının ilk kez tanımlanması ile yıllara göre av veriminin, avlama yöntemlerinin ve av saatlerinin, av verimine etkilerinin tespit edilmesi balıkçılık yönetimi ve sürdürülebilir balıkçılık açısından önemlidir.

Parasite and genetic diversity of big-scale sand smelt (Atherina boyeri Risso, 1810) populations in their natural and expansion ranges in Ukraine.

The big-scale sand smelt (Atherina boyeri) is an Atlanto-Mediterranean amphidromous fish species found within the Black Sea. Here, we assess differences in the parasite fauna of big-scale sand smelt populations from their natural range in the northwestern Black Sea and from their expansion range in the Lower and Middle River Dnipro. In addition, we undertook a microsatellite analysis to assess the genetic similarity of fish from the different locations. We found that the parasite community of fish in their natural range was wider than that from their expansion range. While the Gulf of Odesa was most distant from all other localities by parasite community composition and the Dnipro Reservoir was characterised by an absence of parasites (newest and most distant expansion locality), only fish from the Danube Delta showed a significant genetic difference. Our results suggest that the parasite community of big-scale sand smelt is primarily influenced by environmental factors, such as habitat type, water salinity and/or prey composition. Both microsatellite analysis and parasite community species composition (e.g. the presence of the marine Telosentis exiguus in the Kakhovka Reservoir and freshwater Raphidascaris sp. in the Gulf of Odesa) confirmed that populations in the River Dnipro reservoirs had, at some time, been connected with native marine populations, thus also confirming the species' amphidromous nature.

Gümüş balığının (Atherina boyeri Risso, 1810) geleneksel ve yapay sinir ağları yöntemleriyle büyüme parametreleri

In this study, the growth parameters of big-scale sand smelt (Atherina boyeri Risso, 1810) in İznik Lake has been determined with traditional (length weight relationships (LWRs), von Bertalanffy (VB), condition factor (CF)) and modern approaches (Artificial Neural Networks - ANNs). A total of 635 specimens (44.84% female and 55.16% male) were collected from the local fisherman during the hunting season between April 2018 to April 2019. Mean fork length (FL) (mm, min-max), mean W (g, min-max) and mean CF (value, min-max) were estimated as 67.31 mm (40.10 - 97.77 mm), 2.57g (0.53 - 7.50 g), and 0.790 (0.170-1.520) for all individuals. The length-weight relationships were determined W=0.00001437L2.8602 for female, W=0.00001570L2.8266 for male and W=0.00001328L2.8717 for all individuals. The von Bertalanffy equations were determined Lt=136.218 [1-e(-0.240(t+0.51))] for female, Lt=155.042 [1-e(-0.185(t+0.73))] for male, and Lt=146.916 [1-e(-0.205(t+0.64))] for all individuals. The values in training (MSE (Mean Squared Error) 4.52559e-5, R (correlation coefficients) 9.09347e-1), verification (MSE 4.86111e-5, R 9.00931e-1) and test data (MSE 3.391999e-5, R 9.43465e-1) were found in calculations made with ANNs. It was determined that ANNs could be an alternative for evaluating growth estimation.

Infection of Kudoa anatolica (Cnidaria: Myxozoa): Impact on the Nutritional Composition of Atherina hepsetus (Atherinidae) Flesh

ABSTRACT Mediterranean sand smelt Atherina hepsetus, whose flesh was infected by Kudoa anatolica, was investigated for its impacts on the nutritional composition of host fish. Based on the infection densities of K. anatolica, fish were grouped to have uninfected control (A), slightly (B), moderately (C), and highly infected (D). While there were no significant changes in the crude protein (CP), crude lipid (CL), and energy contents (p > .05), significant changes were determined in the total amino acid content between groups (p < .05). The present study proved changes in the proximate, fatty acid, and amino acid composition in flesh and the negative impacts of a Kudoa species.

ОЦЕНКА СОСТОЯНИЯ ЗАПАСОВ МОРСКИХ ВИДОВ РЫБ ЧЕРНОГО МОРЯ (ВОДЫ РОССИИ) В 2021 Г

Based on the available biological and fisheries data, stock status review for 18 units of the fish species inhabiting the Black Sea and the both Azov and Black Seas is presented. A modified version of the traditional approach to the harvest control rules for the aquatic bioresources of the Azov and Black Sea Fishery Basin is described for the case when they are assessed by the mathematical methods to estimate the current stock biomass and fishing mortality. For 11 stock units, analytical modeling including cohort, production and trend models has been applied. Based on the estimates of biomass and fishing mortality concerning biological reference points, in 2021, the status of six stock units of the marine fish species inhabiting the basin and exploited by the Russian fisheries was identified as increasing or stable (“Black Sea” stock units of the European sprat and European anchovy, “Crimean” stock unit of turbot, “Crimean and Caucasian” stock unit of red mullet, and “Black and Azov Seas” stock units of garfish and rays). Five fishery stock units (“Crimean and Caucasian” of mullets, picarel and Mediterranean horse mackerel, “Black and Azov Seas” of sand smelts, and “Caucasian” of turbot) have shown a decreasing trend in terms of abundance, and for the rest of the investigated fish stock units (“Mediterranean migrant” bluefish, Atlantic bonito and Atlantic mackerel, “Black Sea” whiting, so-iuy mullet and the other marine fish species, “Black and Azov Seas” spiny dogfish), the status has not been determined due to the absence of systematic biological and fishery data.

Diet of Great Cormorants Phalacrocorax carbo in Relation to Fish Resources in the Upper Adriatic Sea

The necessity of balancing conservation issues with the protection of aquaculture activities drives research to quantify the impact of the Great Cormorant Phalacrocorax carbo and to identify the best mitigation strategies. This study aims to characterise the diet in relation to the possible impact of the Great Cormorant on the extensive aquaculture farms in Friuli Venezia Giulia region in the upper Adriatic Sea. The diet of the species was investigated by analysing 459 pellets, collected monthly during the winter 2006/2007 in the three most important roosts of the Friuli Venezia Giulia coastline. Cormorants proved to feed mainly on typical fish species of lagoon and coastal waters. By frequency, Sand Smelts Atherina boyeri (54%) and Flounders Platichthys flesus (26%) were the main prey. Flounders played an important role also in terms of biomass (35%), together with mullets (Mugilidae, 28%). Commercially-important aquaculture species (European Seabass Dicentrarchus labrax and Gilthead Bream Sparus aurata) represented only 2% and 14% by frequency and biomass. The diet analysis supports our previous studies, carried out by behavioural observations on Cormorants foraging at different depths, on interactions with the main prey and strategies of exploitation of the fish farms. Our data imply that the Great Cormorant does not have a large effect on aquaculture yield in the north Adriatic Sea.

Five-years management of an emerging parasite risk (Eustrongylides sp., Nematoda) in a fishery supply chain located on Trasimeno Lake (Italy)

In the last few years, the widespread diffusion of potentially zoonotic parasitic nematodes of the genus Eustrongylides in the Trasimeno Lake, Central Italy, prompted Food Business Operators (FBOs) operating in the freshwater fish supply chain to define preventive measures to reduce or eliminate this new hazard from fishery products. The results of the self-checks for parasite risk management of a fishermen's cooperative over a five-year period (January 2016–April 2021) are presented. Nine freshwater commercial species, perch ( Perca fluviatilis ), largemouth black bass (Micropterus salmoides ), big-scale sand smelt ( Atherina boyeri ), eel ( Anguilla anguilla ), black bullhead ( Ictalurus melas ), carp ( Cyprinus carpio ), tench ( Tinca tinca ), goldfish ( Carassius auratus ), and pumpkinseed sunfish ( Lepomis gibbosus ), differently processed (filleted, whole gutted or whole ungutted), were investigated . The presence of visible parasites was assessed by visual inspection during processing and recorded. Eustrongylides sp. were found in all species examined except for goldfish. Eustrongylides sp. occurrence was negligible in large mouth black bass, eel, carp, and tench, while increasing prevalence rates over the years were observed in fillets of perch <400 g (from 4.2% in 2016 to 68% in 2021), batches of sand smelt (<1%–40%) and pumpkinseed sunfish (6%–99%). Still low but slightly increasing prevalence rates were also observed for black bull head. The rising of the infection in perch, sand smelt, and pumpkinseed sunfish lead to a progressive implementation of preventive measures including the definition of a sampling plan for the visual inspection followed by trimming or removal of the parasites from the muscle or the application of a threshold value to define the marketability of fish batches. This is the first study describing an approach for the management of the emerging risk posed by nematodes of the genus Eustrongylides in a freshwater fishery supply chain. Besides providing an updated epidemiological scenario in Lake Trasimeno, where this parasite was described for the first time in Italy in 2015, it could support other FBOs in the implementation of preventive measures to safeguard consumers' health and trust. • Eustrongylides sp. nematodes are becoming widespread in the Trasimeno Lake, Italy (85). • The local freshwater fishery supply chain is affected by Eustrongylides sp. (85). • 5-years of self-checks for parasites of a fishermen's cooperative are presented (82). • Nine commercial species differently processed were investigated (65). • Prevalence in perch, sand smelt and pumpkinseed sunfish are noticeably increased (85).

Some Growth Properties and Length at First Maturity of Big Scale Sand Smelt (Atherina boyeri Risso, 1810) in İznik Lake, Turkey

In this study, the length at first maturity and growth characteristics of the big scale sand smelt (Atherina boyeri Risso 1810) were investigated in İznik Lake. Catching trials were conducted on a monthly basis at 4 different stations of the lake between March 2014 and February 2015 and beach seine net with 6 mm of codend mesh size was used in the samplings. The overall sex ratio of the subsample was founded as 1:1.46 (F:M; 1180 females, 1729 males). The fork length range were 3.3-11.2 cm for females and 2.9-9.7 cm for males. The growth equations were found as TW=0.005FL3.160 and TW=0.006FL3.067 for female and male respectively. Allometric (+) growth has been shown in both sex groups. According to the logistic regression model results, length at first maturity (L50) was estimated as 4.62 and 4.25 cm fork length for female and male respectively. While the growth properties of the species shown similarity with other habitats of populations, the values of length at first maturity (L50) shown some differences.

Age, growth, reproduction and mortality of Mediterranean sand smelt Atherina hepsetus (Atherinidae) from the Crimea region (the Black Sea)

Sex ratio, size and the age structure, growth, dynamics of gonadosomatic indices and mortality were analyzed for the Mediterranean sand smelt Atherina hepsetus collected in the Crimean coastal area. Overall, 3193 specimens were examined between 2011 and 2021 years. The total sex ratio in the A. hepsetus catches was balanced (1.03:1), but it differed in the older age groups, where females predominate. The maximum total length of females was 15.8 cm, of males was 15.6 cm; its weight was 26.6 g and 23.6 g, respectively. The maximum age for both sexes was 4 years. There was not any statistical difference in sizes and growth between sexes. The values of the parameters of the Bertalanffy equation were calculated: in females, the asymptotic length was 15.94 cm, the asymptotic weight was 25.98 g, the growth constant was 0.53 year −1; for males — 15.90 cm, 24.47 g, and 0.55 year −1, respectively. The exponent values of the length–weight relationships in females was 3.09, in males – 2.96. The growth performance index in females was 2.13, for males — 2.14. Spawning period falls in March–July with the peak in April. The total and fishing mortality rates for both sexes were 1.52 year −1, 1.07 year −1 and 0.45 year −1, respectively; the exploitation ratio was 0.30, that indicated a low fishing pressure. It has been found that Atherina hepsetus from the Crimean waters differs from the Mediterranean Sea populations for the largest sizes and the highest growth rate.

Pathogenic bacteria load and safety of retail marine fish.

This study was conducted to determine the pathogenic bacteria load of 14 species of marine fish obtained from two suppliers (in Bitlis city, Turkey), which provide fish for fish markets, and to reveal the safety of the marine fish in terms of microbiological quality. The counts of total mesophilic aerobic bacteria (TMAB), Staphylococcus aureus, and Escherichia coli, the presence of Salmonella spp. and Listeria monocytogenes were determined in anchovy, horse mackerel, salmon, red mullet, gilthead seabream, bonito, pilchard, common sole, sand smelt, axillary seabream, seabass, Mediterranean horse mackerel, bluefish, and garpike. It was determined that common sole, axillary seabream, seabass, bluefish and Mediterranean horse mackerel obtained from both suppliers were unacceptable in terms of the counts of TMAB. Twenty-four samples exceeded the critical limit of S. aureus and all the samples were unacceptable according to the critical limit of E. coli. While L. monocytogenes was isolated from 50.0% of the samples, Salmonella spp. was isolated from 39.3% of the samples. These results showed that the pathogenic bacteria load of the analyzed marine fish was quite high and they were unsafe in terms of microbiological quality.

Length-weight relationships and condition factors of the sand smelt Atherina boyeri (Risso, 1810) estimated from commercial and experimental catches in Lake Trichonis (Western Greece)

Total length-weight relationships (LWRs) from 3583 individuals of Atherina boyeri (Risso, 1810) caught in Lake Trichonis (Western Greece), using a commercial encircled net and experimental Nordic type benthic and pelagic multi-mesh gillnets, were estimated during 2019-2020. The variation of the parameter b for all seasons combined was significantly allometric, for both encircled towed and gillnets, with a quite robust fit (R^2 equals 0.925 and 0.947, respectively) and values equal to 2.254 and 2.089, respectively. The specimens were significantly lighter in summer than in the other seasons. The slopes of the LWRs significantly differ between seasons and exhibited relatively low values when compared to other ecosystems worldwide and in the same ecosystem in previous periods of time. Τhe estimated values of the Le Cren index were significantly higher than the Allometric and the Fulton ones.

Genetic Variation of Sand Smelt Fish in Egyptian Fisheries

Genetic Variation of Sand Smelt Fish in Egyptian Fisheries

The Effect of Wall Material Type on the Encapsulation Efficiency and Oxidative Stability of Fish Oils.

Fish oil is the primary source of long-chain omega-3 fatty acids, which are important nutrients that assist in the prevention and treatment of heart disease and have many health benefits. It also contains vitamins that are lipid-soluble, such as vitamins A and D. This work aimed to determine how the wall material composition influenced the encapsulation efficiency and oxidative stability of omega fish oils in spray-dried microcapsules. In this study, mackerel, sardine waste oil, and sand smelt fish oil were encapsulated in three different wall materials (whey protein, gum Arabic (AG), and maltodextrin) by conventional spray-drying. The effect of the different wall materials on the encapsulation efficiency (EE), flowability, and oxidative stability of encapsulated oils during storage at 4 °C was investigated. All three encapsulating agents provided a highly protective effect against the oxidative deterioration of the encapsulated oils. Whey protein was found to be the most effective encapsulated agent comparing to gum Arabic and maltodextrin. The results indicated that whey protein recorded the highest encapsulation efficiency compared to the gum Arabic and maltodextrin in all encapsulated samples with EE of 71.71%, 68.61%, and 64.71% for sand smelt, mackerel, and sardine oil, respectively. Unencapsulated fish oil samples (control) recorded peroxide values (PV) of 33.19, 40.64, and 47.76 meq/kg oil for sand smelt, mackerel, and sardine oils after 35 days of storage, while all the encapsulated samples showed PV less than 10 in the same storage period. It could be concluded that all the encapsulating agents provided a protective effect to the encapsulated fish oil and elongated the shelf life of it comparing to the untreated oil sample (control). The results suggest that encapsulation of fish oil is beneficial for its oxidative stability and its uses in the production of functional foods.

Do Sand Smelt (Atherina presbyter Cuvier, 1829) Larvae Discriminate among Conspecifics Using Different Sensory Cues?

The ability of shoaling fish to recognise and differentiate between potential groupmates may affect their fitness and survival. Fish are capable of social recognition and multiple sensory cues mediate the recognition mechanisms. This has been comprehensively studied for juvenile and adult freshwater species. However, the recognition ability and mechanisms intervening during the larval phase of marine species are yet poorly understood. Fish larvae are capable of discriminating conspecifics from heterospecifics based on chemical and/or visual cues, but whether this recognition occurs at finer scales, such as discerning among conspecifics of different reefs, is yet understudied. Here, we tested the hypothesis that larvae of a marine fish species, the sand smelt (Atherina presbyter Cuvier, 1829), are able to recognise and associate with conspecifics of their natal reef versus conspecifics of a non-natal reef based on three sensory modalities—chemical, visual, and chemical and visual simultaneously. Results do not support our hypothesis, but still provide evidence of group cohesion and indicate large differences in the relative importance of the different senses when associating with conspecifics, with visual cues playing a more important role than chemical cues alone.

Çekerek Barajı'ndan (Yozgat, Turkey) Avlanan Gümüş Balığının (Atherina boyeri) Yağ Asidi ve Besin Kompozisyonundaki Mevsimsel Değişimleri

Seasonal variations of proximate and fatty acid compositions of the muscle tissue of sand smelt (Atherina boyeri) harvested in Cekerek (Sureyyabey) Dam were investigated. Seasonal nutritional composition of sand smelt muscle in October, March and July were found as 17.00%; 16.72%; 15.64% for protein, 1.95%; 2.00%; 2.86% for lipid, 79.25%; 79.17%; 78.06% for moisture and 1.80%; 2.10%; 2.49% ash, respectively. Sand smelt showed the lowest protein values in summer, while the highest protein values were observed in autumn and spring. The highest lipid content of sand smelt was found in summer (P &amp;lt; 0.05). The moisture content of sand smelt in summer was significantly (p&amp;lt;0.05) lower than those of the content in autumn and spring. The lowest ash content was observed in autumn (1.80%) whereas sand smelt gave the highest ash level was in summer. During the seasons, the proximate and FA composition values of sand smelt showed variations (p&amp;lt;0.05). Seasonal fatty acid compositions of sand smelt ranged from 24.63 to 25.69% for saturated fatty acid (SFA), from 20.75 to 26.43% for monounsaturated (MUFA), and from 28.29% to 36.11% polyunsaturated fatty acid (PUFA). Palmitic acid (16:0), stearic acid (18:0), palmitoleic acid (16:1ω7), oleic acid (18:1ω9), linoleic acid (LA, 18:2ω6), arachidonic acid (ARA, 20:4ω6), linolenic acid (18:3ω3), eicosapentaenoic acid (EPA, 20:5ω3) and docosahexaenoic acid (DHA, 22:6ω3) were major fatty acids of sand smelt in different seasons. The highest proportion of EPA (5.59-7.22%) and DHA (12.33-19.77%) were observed in spring. The results showed that sand smelt is good source of n-3 PUFAs and is rich in EPA+DHA for human nutrition.

HISTOPATHOLOGICAL ASPECTS CAUSED BY NEMATOD PARASITE Eustrongylides excisus OBSERVED IN SOME FISH SPECIES OF EĞIRDIR LAKE, TURKEY

The present study was carried out between January and October 2018, in order to determine the infection of Eustrongylides excisus Jägerskiöld, 1909 in some fish species inhabiting Eğirdir Lake - the second largest freshwater lake of Turkey. Parasite infection was detected in host species belonging to Konya tooth-carp (Aphanius iconii Akşiraz, 1948), Big-scale sand smelt (Atherina boyeri Risso, 1810), Caucasian dwarf goby (Knipowitschia caucasica Berg, 1916) and pike-perch (Sander lucioperca Linnaeus, 1758). The highest prevalence of infection (21.4%) was determined in S. lucioperca. The mean intensity ranged from 1.25 nematode/fish in K. caucasica to 2.3 nematodes/fish, in S. lucioperca. The nematode E. excisus was recorded for the first time on Caucasian dwarf goby, a non-native fish species in Eğirdir Lake. In addition, this research provides useful data regarding histopathology effects of E. excisus in all studied teleost species. Hyperaemia, edema, microhaemorrhages, inflammatory reaction and necrosis were observed around the encysted parasites.

Length-Weight Relationship of the Sand Smelt (Atherina boyeri Risso, 1810) Population Distributed in Lake Bafa (Aydın)

Gümüş balığı (Atherina boyeri Risso, 1810), doğal olarak denizler ve lagün bölgelerinde yayılış gösteren örihalin bir türdür. Bu tür, balıkçılık amacıyla, resmȋ kuruluşların bilgisi olmadan doğal göllere ve yapay göletlere de taşınmış ve Türkiye’de, deniz ile doğrudan bağlantısı bulunmayan pek çok göl ve rezervuarda son yıllarda hızla yayılmıştır. Bu çalışmada, Bafa Gölü’nde, Eylül 2018 ve Mayıs 2019’da yapılan örnekleme çalışmalarından elde edilen toplam 2204 adet gümüş balığı bireyinin boy-ağırlık ilişkileri incelenmiştir. Balıkların total boy dağılımı, 5,0-10,7 cm arasında değişim göstermektedir. Ortalama total boy ise 7,51±0,023 cm olarak hesaplanmıştır. Bireylerin toplam ağırlık dağılımı 1,10-10,08 g arası değişim göstermekte olup, ağırlık ortalaması 3,32±0,033 g olarak hesaplanmıştır. Boy-ağırlık ilişkisi eşitliği W=0,0082L2,9418, sh(b)=0,018 r=0,947 olarak hesaplanmıştır. Bafa Gölü gümüş balığı örneklerinde negatif allometrik büyüme modeli gözlenmiştir.

The effects and interactions of three invasive fish species introduced to the aquatic ecosystem of a Turkish Lake (Eğirdir Lake)

We studied feeding behavior and prey selection of topmouth gudgeon (Pseudorasbora parva), big-scale sand smelt (Atherina boyeri) and pike-perch (Sander lucioperca) in Lake Egirdir, the second largest freshwater lake in Turkey. Fish specimens were collected between January and August in 2010 and 2011 using gill-nets and purse seines. A total of 941 specimens were analyzed for stomach contents analysis. We expressed the importance of the food items present in their guts with the relative importance index (IRI) and estimated their diet selectivity indices with Pearre’s index. Pseudorasbora parva had a diverse diet comprising mainly Nitokra hibernica (copepod), Chydorus sphaericus, and Bosmina longirostris (cladoceran) (each, at p 0.05). Big-scale sand smelt often preferred B. longirostris, N. hibernica, and Alona quadrangularis (each at p 0.05), Carassius gibelio was not preferred by pike-perch as food item (p > 0.05). Our results indicate that invasive species altered the food chain in Lake Egirdir. Thus, because these fish species constitute a major threat for native fish species for food and breeding grounds, extensive care should be taken to prevent invasive fish species entering lakes in Turkey.

Monitoring Skeletal Anomalies in Big-Scale Sand Smelt, Atherina boyeri, as a Potential Complementary Tool for Early Detection of Effects of Anthropic Pressure in Coastal Lagoons

Mediterranean coastal lagoons are increasingly affected by several threats, all concurrently leading to habitat degradation and loss. Methods based on fish for the assessment of the ecological status are under implementation for the Water Framework Directive requirements, to assess the overall quality of coastal lagoons. Complementary tools based on the use of single fish species as biological indicators could be useful as early detection methods of anthropogenic impacts. The analysis of skeletal anomalies in the big-scale sand smelt, Atherina boyeri, from nine Mediterranean coastal lagoons in Italy was carried out. Along with the morphological examination of fish, the environmental status of the nine lagoons was evaluated using a method based on expert judgement, by selecting and quantifying several environmental descriptors of direct and indirect human pressures acting on lagoon ecosystems. The average individual anomaly load and the frequency of individuals with severe anomalies allow to discriminate big-scale sand smelt samples on the basis of the site and of its quality status. Furthermore, a relationship between skeletal anomalies and the environmental quality of specific lagoons, driven by the anthropogenic pressures acting on them, was found. These findings support the potentiality of skeletal anomalies monitoring in big-scale sand smelt as a tool for early detection of anthropogenic impacts in coastal lagoons of the Mediterranean region.

Growth, mortality and yield of Atherina boyeri Risso, 1810 from Lesina lagoon (Adriatic Sea, Italy)

Population structure, growth, age, mortality and exploitation status of Atherina boyeri, caught in the period from June 2013 to May 2014 in the Lesina lagoon (Apulia region, southern Adriatic) was studied. Samples were taken each month by using beach seines . The length–weight relationship of all sand smell specimens was described by the equation W=0.012*TL 3.10; (R2= 0.84). Population parameters including the asymptotic length (L∞) and growth coefficient (K) were assessed to evaluate the stock status. The recruitment pattern was modeled with a FiSAT routine. The asymptotic length (L∞) was 111.0 mm, while the growth coefficient (K) was 0.68 year−1. The growth performance index ((φ’) reached 3.92. The total mortality coefficient “Z”, the natural mortality coefficient “M” and the fishing mortality coefficient “F” were estimated as 2.24, 1.48 and 0.76 year-1, respectively. Exploitation rate for the population of A. boyeri in the Lesina lagoon estimated as 0.34 was resulted still lower than the predicted maximum value of Emax 0.59. The probability of capture indicated that L50 was of 55.57 mm, indicating that the stock of sand smelt in Lesina lagoon is not being over-fished.