Bluefish Research Articles

Maximizing cardiovascular benefits of fish consumption within the One Health approach: Should current recommendations be revised?

AimsCurrent dietary recommendations on fish consumption for cardiovascular disease (CVD) prevention put somewhat vague emphasis on fatty fish, mainly driven by evidence on the cardioprotective effects of n–3 PUFAs. Recent data on the consumption of different types of fish in relation to hard cardiovascular endpoints suggests that fatty but not lean fish can contribute to CVD prevention. This considered, we aimed at evaluating, by an environmental perspective, fish consumption limited to the fatty type – in appropriate amounts for optimizing CVD prevention – within the European context. Data synthesisStarting from the current average intake of total fish by the European population (i.e., 2 servings/week of fatty plus lean fish), we show that the shift towards the consumption of 2 servings/week of solely fatty fish – appropriate for optimizing CVD prevention – would allow a 32% saving of greenhouse gas (GHG) emissions related to fish consumption. This is due to the lower environmental impact of fatty fish globally considered, compared to lean fish. However, since the carbon footprint of different fatty fish species can vary significantly – with small blue fish (e.g., anchovies, sardines, herrings) in the lowest range, we estimated that GHG emissions due to fish consumption in Europe could be reduced by 82% by focusing on small blue fish consumption. ConclusionsConsumption of 2 servings/week of small blue fish could represent a feasible and effective choice among the functional dietary strategies available to achieve the maximal benefits for human and environmental health.

Occurrence, bioconcentration, and human health risks of pharmaceuticals in biota in the Sea of Marmara, Türkiye

The presence, bioconcentration, and health risk via seafood consumption of 11 pharmaceutical compounds belonging to different therapeutic groups (anti-inflammatory, antiepileptic, lipid regulators, and hormones) were investigated in the muscle tissues of fish and the meat of shrimp in the Sea of Marmara. Six biota species (Merlangius merlangus, Trachurus meditterraneus, Serranus hepatus, Pomatomus saltatrix, Parapenaeus longirostris, Spratus sprattus) were collected from the five stations in October and April 2019. Ultrasonic extraction method followed by solid phase extraction was used for extraction of pharmaceutical compounds from biota samples and then analyzed using high-performance liquid chromatography. Of the 11 compounds, 10 were detected in biota species. Ibuprofen was the most frequently detected pharmaceutical in the biota tissues at high concentrations (<3.0–1225 ng/g, dw). The other widely detected compounds were fenoprofen (<3.6–323 ng/g, dw), gemfibrozil (<3.2–480 ng/g, dw), 17α-ethynylestradiol (<2.0–462 ng/g, dw), and carbamazepine (<7.6–222 ng/g, dw). The bioconcentration factors of the selected pharmaceuticals calculated in various aquatic organisms ranged from 9 to 2324 L/kg. The estimated daily intakes of anti-inflammatories, antiepileptics, lipid regulators, and hormones via seafood consumption were 0.37–568, 1.1–324, 8.5–197, 3–340 ng/kg bw. Day, respectively. Based on hazard quotients, estrone, 17β-estradiol, and 17α-ethynylestradiol may pose a health risk to humans through the consumption of this seafood.

Evaluation of Growth Performance and Improving Genetic Gain of Blue Tilapia (&lt;I&gt;Oreochromis aureus&lt;/I&gt;) Fourth-generation (F-4) at Brackish Water Pond

Highlight Reseacrh The study showed that the selected F-4 blue tilapia had a better growth pattern than the control (non-selection) F-4 blue tilapia The difference in performance between the two populations of blue tilapia is an illustration of the genetic improvement that is passed on from parents to offspring as a result of the selective breeding The realized heritability value of the weight character of F-4 blue tilapia in the high category There was an increase in growth in the F-4 blue tilapia population with a positive response to selection Abstract Breeding program in order to increase genetic improvement in blue tilapia have not been widely carried out at brackish water ponds. This study aimed to evaluate the increase in growth and genetic gain of F-4 blue tilapia from family selection in ponds with 25-30 gL-1 salinity. The parent used for the formation of F-4 is the selected parent F-3 and as a control using the non-selected parent F-3. Spawning was carried out in a full-sib mating design using the family selection method. The ratio of male and female broodstock is 1: 2. Spawning and nursery activities of F-4 blue tilapia are carried out in freshwater. The enlargement test was carried out in the net cage 5m x2.5m x1 m which was installed in the ponds with a salinity of 25-35 g l-1 for 120 days, at a stocking density of 10 fish m-2. At the end of maintenance, a selection process is carried out on the weight traits. Parameters observed included growth, survival, and genetic values. The results showed that the growth and survival in the F-4 blue tilapia population, male and female selected populations, had a higher value than in the non-selected population. The realized heritability value of the population growth character of the F-4 blue fish is in the high category. The difference in the average weight of the selected blue tilapia and the control was equivalent to an increase in genetic value added by 15.06% (male population) and 17.92% (female population).

Identifying trade-offs and reference points in support of ecosystem approaches to managing Gulf of Mexico menhaden

Gulf menhaden (Brevoortia patronus) support the largest fishery by yield in the Gulf of Mexico (GoM) and are a key forage species for many marine predators. While menhaden stock assessments indicated that overfishing was not likely to have occurred in the past, concerns have been raised regarding the possible effects of menhaden fishing on their predators. In this study, we used a US Gulfwide Ecopath with Ecosim (EwE) model to explore the predicted effects of increased menhaden harvest on the GoM ecosystem and focused our analyses on Gulf menhaden predators. Key menhaden predators identified included king mackerel (Scomberomorus cavalla), Spanish mackerel (Scomberomorus maculatus), sea trout (Cynoscion spp.), red drum (Sciaenops ocellatus), and pelagic coastal piscivores [e.g., bluefish (Pomatomus saltatrix)]. As expected, these predators exhibited reduced biomass in response to increased Gulf menhaden harvest, with a predicted 11% decrease in predator biomass at simulated fishing levels near historical highs. Our results indicate strong relationships between the effects of menhaden fishing and the predator fishing mortality for king mackerel and intermediate relationships for Spanish mackerel, blacktip shark (Carcharhinus limbatus), red drum, large coastal sharks, and pelagic coastal piscivores. Biomass of predator groups such as demersal coastal invertebrate feeders [e.g., drums and croakers (Sciaenidae)] are more affected by menhaden harvest (through trophodynamics interactions and bycatch removal) compared to the isolated effect of their fishing mortality. For almost all the groups examined in the trade-off analysis, with the exception of sea trout, current biomass (2016) was higher than their target biomass representing 75% of their biomass at maximum sustainable yield. In comparison to the time series of fishing mortality rates estimated by the most recent Gulf menhaden stock assessment, the mean ecological reference point (ERP) of 0.862 was exceeded in all but 1 year from 1977 to 2007; however, neither the target nor threshold upper ERP value has been exceeded since 2008. The observed Gulf menhaden landings from 2003 to the present were generally within the range of the projected equilibrium landings (i.e., within confidence intervals) at both the ERP target and threshold values except for three recent years.

Navigating Technological Obsolescence: Analysis and Reconstruction of Stockhausen’s Mikrophonie I

This article outlines analytical methods for preparing and interpreting Karlheinz Stockhausen’s sextet Mikrophonie I (1964) for tam-tam and electronics. Would-be performers of this work face significant accessibility issues: Stockhausen’s recommended equipment—especially the electronic filter used to process the tam-tam’s sound—is extremely rare. These issues often necessitate performers finding alternative solutions for equipment. Mikrophonie I is one of several works for live electronics that have become increasingly difficult to program, due to the obsolescence of the technology required to perform them. Performers often reconstruct the necessary electronics digitally, using software such as Max/MSP. Wetzel [(2006). “A Model for the Conservation of Interactive Electroacoustic Repertoire: Analysis, Reconstruction, and Performance in the Face of Technological Obsolescence.” Organised Sound 11 (3): 273–284. https://doi.org/10.1017/S1355771806001555] describes a three-stage model for this reconstructive process that foregrounds the need for performer-led analysis. Using Mikrophonie I as a case study, I expand on Wetzel’s model to navigate the reconstruction through two main analytical perspectives: the prioritisation of sound or process. These methods are then applied to my realisation process of Mikrophonie I. I describe the process of constructing a digital filter in Max/MSP based on a patch created by Christopher Burns [(2002). “Realizing Lucier and Stockhausen: Case Studies in the Performance Practice of Electroacoustic Music.” Journal of New Music Research 31 (1): 59–68. https://doi.org/10.1076/jnmr.31.1.59.8104] and compare different interface options for using the filter in performance. Referring to previous recordings by the Stockhausen Ensemble (1965) and the percussion ensemble red fish blue fish (2014), I show how creative interpretations can help ensembles overcome the perceived shortcomings of their available tam-tam. Beyond the specifics of reconstructing the technology required for performing Mikrophonie I, this article underlines the indispensability of analysis for performers who specialise in works with obsolescent technology.

Morphological and molecular characterization of Hysterothylacium spp. parasitizing Pomatomus saltatrix and Pagrus pagrus of the State of São Paulo, Brazil.

Raphidascarid nematodes have been the focus of several studies, mainly due to the zoonotic potential of some species, even though the cases are underreported. Due to the difficulty in identifying their larvae, the use of diagnostic techniques involving morphological and molecular analyses has grown in the last 20 years. The present study had as objective the morphological and molecular characterization of the L3 larval types of Hysterothylacium collected in Pomatomus saltatrix and Pagrus pagrus from the Brazilian coast, close to the municipality of Santos, State of São Paulo. Twenty specimens of P. saltatrix were necropsied and Hysterothylacium type V (n = 257) and Hysterothylacium type X (n = 5) larvae were found. Five specimens of P. pagrus were necropsied and all were parasitized by Hysterothylacium type V larvae. The analyses showed a genetic proximity relationship between Hysterothylacium types V with other Hysterothylacium V and with H. deardorffoverstreetorum, although this is a species inquirenda. Haplotypes for Hysterothylacium type X found in the present study formed a monophyletic group with other Hysterothylacium X, H. amoyense, and H. zhoushanense. Through this study, new hosts and localities were registered for Hysterothylacium type V and Hysterothylacium type X.

Age and growth of Pomatomus saltatrix in the south-western Pacific Ocean (eastern Australia), with a global comparison

Context Pomatomus saltatrix is one of few globally distributed pelagic mesopredators that is exploited heavily throughout its range. Despite the implementation of management strategies, the south-western Pacific Ocean (eastern Australian) population has few published estimates of the key life-history parameters including growth. Aims To estimate the age and growth of P. saltatrix in the south-western Pacific and compare these with the age and growth in other populations. Methods Age estimates were made using whole otolith readings and an age–length key was used with a length frequency distribution to estimate the age structure of the population. Eight different growth models were compared within a Bayesian framework for both juvenile and overall growth. Key results The Schnute growth equation provided the best fit for overall growth and yielded parameter values of a = −0.15, b = 2.56, Size-at-age 1 = 24.38-cm fork length (FL) and Size-at-age 4 = 47.36 cm FL. Conclusions P. saltatrix in the south-western Pacific has a growth rate similar to that in other populations of P. saltatrix. Implications Despite its geographically and genetically distinct populations, P. saltatrix demonstrates a generally consistent life-history strategy of fast growth and high mortality, except for the north-western Atlantic population, which has lower mortality.

Efficacy of natural and consumer-friend applications to control Aeromonas hydrophila growth in Bluefish

Fish is one of the main transmission routes of Aeromonas (A.) hydrophila, an emerging pathogen that threatens public health due to its high antibiotic resistance. This study aimed to control the growth of A. hydrophila in cold-stored Bluefish (Pomatomus saltatrix) using natural, consumer-friendly practices. Samples were inoculated with A.hydrophila, dipped or sprayed with acetic acid, citric acid, ascorbic acid, sodium lactate, or sodium chloride solutions (4%), and stored at 4°C. Dipping was very effective since the growth of A. hydrophila was inhibited by all dipping treatments and remained below the inoculation dose after 72 hours. During this time, dipping in acetic acid, ascorbic acid, and citric acid reduced the initial load of A. hydrophila (7.03 log cfu/g) to 5.27, 5.51, and 5.64 log cfu/g, respectively. Acetic acid, ascorbic acid, and citric acid dipping treatments reduced the A. hydrophila number 1 log/cfu more than other treatments (P&lt;0.05). Acetic acid and ascorbic also provided the best results for the sprayed samples. Our results showed that dipping in natural acids such as acetic acid, ascorbic acid, and citric acid yielded successful results in inhibiting A. hydrophila growth. Using consumer-friendly, natural substances to ensure food safety by controlling the growth of this emerging pathogen will provide significant benefits for the food industry.

Occurrence of Ceratothoa capri (Trilles, 1964) in Pomatomus saltatrix (Linnaeus, 1766) in the Libyan Coasts

Ceratothoa is an important ectoparasite affecting many species of commercial fish. 40 individuals of wild bluefish, Pomatomus saltatrix (L, 1758), were collected during October and November 2022. One pullus Cetratothoa capri parasite was found inside the bluefish gill, P. saltatrix from the coasts of Libya, in the southern Mediterranean determination, the infection rate of the fish was 2.5%. This is the first study from Libya on the presence of C. capri in bluefish.

Histamine in fish products on Croatian market

It is recommended to eat blue fish at least twice a week, due to its high nutritional value and ingredients, primarily healthy fats and proteins. In addition to its advantages, the consumption of fish and fish products can bring potential hazards. Histamine poisoning has been reported as one of the most common issues related to seafood consummation. It is considered as relatively mild illness with symptoms like rash, urticaria, nausea, vomiting, but in some cases, due to high sensitivity, it can lead to severe symptoms and even to death. In order to insure safety of fish products, histamine determination is one of the safety requirements of European and Croatian legislation (Law on food hygiene and microbiological criteria for food, NN 83/2022). Despite that, there has been several recalls of fish products by Ministry of Agriculture from Croatian market in recent years. The aim of this paper was to determine histamine levels in 20 different products from Croatian retail stores by HPLC method. All tested samples have been in accordance with legally determined limits for histamine levels.

Improving the performance of a generic fisheye as a secondary bycatch reduction device in a south-eastern Australian penaeid-trawl fishery

The utility of a generic device (termed a ‘fisheye’) and its simple modification for cumulatively reducing bycatch in penaeid trawls was assessed during two experiments in a south-eastern Australian fishery. In the first experiment, conventional trawls (with no fisheye) were compared to simultaneously towed, identical trawls installed with a typical fisheye (termed ‘mesh fisheye’) comprising an open triangular frame terminating in a semi-elliptical vertical opening (350 × 150 mm) in the top of the trawl extension at 1.1 m anterior to the codend drawstring. Trawls with the mesh fisheye maintained catches of penaeids (mostly school prawns, Metapenaeus macleayi) but retained significantly less total bycatch (by 39 %) and fewer unwanted southern herring, Herklotsichthys castelnaui (by 60 %) and tailor, Pomatomus saltatrix (by 52 %). During the second experiment, trawls with the mesh fisheye were simultaneously compared to those with a modified design comprising a solid panel of aluminium in the lower half of the triangular frame (termed the ‘solid fisheye’). The solid fisheye excluded significantly more bycatch (by 52 %) and small southern herring (by 47 %), and also the numbers of several other species, including mulloway (by 38–41 %) without affecting penaeid catches. The improved performance of the solid fisheye was attributed to its greater anterior displacement of water and posterior area of lower perceived flow for fish. The results and simplicity of the fisheye modification support not only its regional use, but also testing in other national and international fisheries.

Genetic variation rs1121980 in the fat mass and obesity-associated gene (FTO) is associated with dietary intake in Koreans.

Fat mass and obesity-associated gene (FTO) is a well-known gene associated with body weight and obesity risk. Recent studies have suggested that genetic variations in FTO may play a role in the regulation of food preference and consumption. However, little is known with respect to Asian populations. This study examined whether rs1121980 C > T in FTO is associated with food intake in Koreans. This study was performed using data from the Korean Genome and Epidemiology Study (Ansan/Ansung cohort). Dietary intake was determined using the semi-food frequency questionnaire, and the FTO rs1121980 genotypes of 6,262 individuals (3,049 males and 3,213 females) were analyzed along with sex and body mass index (BMI). Genetic variation did not show a significant association with the population's energy-nutrient intake. However, female T allele carriers with BMI ≥ 25 consumed more blue fish and coffee, and their coffee creamer consumption was decisively higher than that of T allele non-carriers (P adjusted = 0.004). In males, the presence of the T allele showed a putative association with the consumption of sweets, snacks, and coffee creamer by the BMI level. The FTO rs1121980 variation was associated with a preference for foods particularly high in fat (e.g. coffee creamer, blue fish, sweets, and snacks) in Koreans; these preferences varied by sex and BMI.

Drivers of fish choice: an exploratory analysis in Mediterranean countries

Fish is an important source of healthy proteins and an important economic sector in Mediterranean countries. Despite the wealth of knowledge acquired in Western countries, a gap has been found in studies in developing countries, as in the Mediterranean southern shore. Therefore, we aimed to investigate consumers’ perceptions of finfish attributes, with qualitative tools as focus groups, given the exploratory nature of the research. The focus groups have been held in Italy, Lebanon, Spain, and Tunisia; in each country, one was held in seaside areas and one in inland areas, in order to control for the availability of fish that shapes consumers’ evaluations and expectations. The focus groups have been analysed through content and semantic analyses. Results of the study yielded main themes recurring in the discussions that have been categorized along such dimensions: (1) definition of fish products; (2) context; (3) search attributes; (4) experience attributes; and (5) credence attributes. Among attributes, the ones mostly guiding consumers’ choices seem to be freshness and fish species, which are used as proxies for quality and sensory attributes. Most of the respondents preferred delicate white fish, while some exceptions were found in Tunisian respondents preferring blue fish and they also were the only ones who were not looking for convenient and already cleaned products. Trust also represented a critical element in guiding the decisions of consumers: with a lack of trust, consumers deviate from preferring local products, as noticeable especially in Lebanese respondents’ opinions. Credence attributes such as animal welfare and sustainability received a minor attention from all the respondents.

Histamine content in fresh and frozen pelagic species from the Mauritanian Atlantic Coast

Histamine is a security issue in food safety as an indicator of the freshness of consumed fish product; that is why we aimed in this study to determine the histamine content in 7 fish species (Scomber japonicus; Sarda sarda; Sardinella aurita; S. maderensis; Ethmalosa fimbriata; Pomatomus saltatrix and Trachurus trachurus). Hundred and eight frozen and fresh pelagic of scombroid and non-scombroid species were collected from the Nouakchott fish market (Mauritanian Atlantic coast) in different period of 2020 and 2021. Histamine was quantified by the technique of high-performance liquid chromatography with a fluorescence detector (HPLC-FLD). Histamine was detected in all analyzed fresh and frozen species and varied from 4.21 to 201.60 ppm. All evaluated fresh fish species (S. aurita; S. maderensis; E. fimbriata; P. saltatrix and T. trachurus) were conform to the FAO/WHO and the European commission regulations. Regarding investigated frozen fish species (S. aurita; S. japonicus and S. sarda); the scombroid species (S. japonicus and S. sarda) were all under the set limits; however, even its more likely for scombroid fish to develop histamine, our results showed that histamine exceed the limit in one sample of non-scombroid fish (S. aurita). No significant variation in histamine levels between scombroid and non-scombroid fish species was obtained; thereby, the study showed that fish product commercialized at the Nouakchott fish market have a good quality and safe for human consumption.

Comparative Study of the Gastric Mucosa of Risso's Dolphin (Grampus griseus) and Bottlenose Dolphin (Tursiops truncatus): A Key to Manage the Diet in Captive Conditions.

Simple SummaryThe bottlenose dolphin (Tursiops truncatus) is the most represented species housed in zoological settings in Western countries, while Risso’s dolphin (Grampus griseus) is usually kept under human care as a result of the rehabilitation process in rescue centers. Although they belong to the same family, Delphinidae, these two species present remarkably different feeding habits. Risso’s dolphin is strictly teutophagous, and its diet is particularly based on cephalopods such as mesopelagic squid, which is poor in histamine. The bottlenose dolphin is mainly ichthyophagous and primarily prefers blue fish, which is rich in histamine as a degradation product and stimulates the parietal cells of the stomach to secrete hydrochloric acid (HCl). These different eating habits are usually correlated to habitat, behavior and physiological needs related to the specific morpho-functional conditions of the species. Despite these dietary differences, in captivity, the two species are fed in the same way through the administration of several kilograms of bony fish (such as capelin or herring) per day. While this diet appears to be optimal for the bottlenose dolphin, Risso’s dolphin appears to be more sensitive, presenting gastrointestinal discomfort when ingesting bony fish for a few consecutive days.To histologically evaluate the gastric compartments of Risso’s (Grampus griseus) and bottlenose dolphins (Tursiops truncatus) and provide suggestions for the diet of Risso’s dolphins in captivity, we examined 12 stomachs from both species. While slight differences in keratinization were observed in the forestomach, significant differences came to light in the second stomach’s mucosa. At this level, in Risso’s dolphin, the principal cells are markedly reduced in size and located externally to the parietal cells, not interspersed between them, compared to bottlenose dolphins; differences were also observed in the structure and concentration of the parietal and principal cells of the gastric body glands (p < 0.0001). The quantitative results of G- and D-cell counts in the gastric mucosa show a clear difference, with a higher concentration of G cells in the mucosa of Risso’s dolphin (t = 7.334; p < 0.0001) and a higher level of D cells in bottlenose dolphin mucosa (t = 3.123; p = 0.0049). These results suggest that parietal cells undergo greater stimulation by gastrin produced by G cells, with greater acid secretion in G. griseus. Further studies are needed to understand whether an inappropriate diet could lead to severe clinical signs due to gastric acidity in Risso’s dolphin.

Variation in the stable isotope trophic position of the bluefish Pomatomus saltatrix (Linnaeus, 1766) from two Mediterranean sites: insights from a global meta-analysis

A direct consequence of sea warming is the shift in the distribution range of thermo-tolerant species that have the potential to determine novel inter-specific interactions, ultimately altering food web structures and ecosystem processes. In this study, we investigated the trophic position of the bluefish Pomatomus saltatrix (Linnaeus, 1766), a pelagic predator that has recently expanded its distribution in the Mediterranean basin and for which scant information is available on its functional role in recently-colonised areas. Nitrogen and carbon stable isotopes were determined in muscle tissues of bluefish specimens collected in south-east Italy in the Gulf of Taranto (NW Ionian Sea) and in the Strait of Otranto (SW Adriatic Sea) at two coastal sites showing contrasting oceanographic conditions. The bluefish trophic position (TP) was estimated using locally abundant forage fish species as isotopic baselines. The results indicated for bluefish from the Strait of Otranto a TP value of 5.1, significantly higher than that determined in the Gulf of Taranto (4.2), and exceeding stomach content-based estimations reported by the online database FishBase and by literature sources. A synthesis of 30 publications reporting isotopic data for the bluefish and its potential prey at a global scale indicated that the species’ trophic position varied considerably between 2.7 and 5.2. The observed variability depended on locationand on the baseline species used in the estimations. Yet, a significant difference in trophic position was observed for bluefish from transitional and inshore environments as compared with offshore areas, mirroring the results obtained from the Gulf of Taranto and the Strait of Otranto. The findings of the study highlight the high trophic plasticity characterizing the bluefish in recently colonized areas, suggesting that it may play a key role in facilitating the expansion of its distribution range. However, additional investigations are essential to provide an advanced resolution of the bluefish functional role in Mediterranean coastal food webs.

Predator fishes are more intelligent than you might think

If you have ever snorkelled before, you would know that it is hard to catch a fish in the ocean. Equally, trying to collect a fish from a tank is very difficult, sometimes almost impossible. You may think that being unpredictable makes it hard to catch fish, and in the marine world, avoiding being caught can mean staying alive. Even though behaving unpredictably may appear to be crucial for survival, a recent study in Proceedings of the National Academy of Sciences has shown that predators may be able to overcome the unpredictability of their prey and adapt to outwit them.Although it is well established that unpredictable behaviour is common among a variety of species, only few studies have been able to recreate wildlife responses in a laboratory setting. Knowing this motivated Andrew Szopa-Comley and Christos Ioannou from the University of Bristol, UK, to find out how the predatory bright blue acara cichlid fish (Andinoacara pulcher) pursue a Bluetooth-controlled robot prey determine how they reacted to the robot victim's escape attempts. First, the researchers trained the elegant blue fish to chase the roboprey in a tank. Then, once the cichlids were happy to pursue the robot, the researchers divided them into two groups: one in which the roboprey always fled along the same departure angle, selected depending on the initial direction the roboprey fled during the fish's first successful trial; and a second group where the roboprey's initial escape angle varied from trial to trial. After recording a total of 117 trials over a 3-week period, filming the fish to analyse their responses, Szopa-Comley and Ioannou determined the time the predators took to reach the roboprey, the predators’ behaviour during the approach phase and their behaviour while pursuing the fleeing victim.Despite the roboprey's sometimes unpredictable behaviour, Szopa-Comley and Ioannou determined that the blue cichlid predator took the same amount of time to capture its target, regardless of the roboprey's escape strategy. When the roboprey consistently took the same departure angle, the fastest fish always pursued the roboprey as it fled from the fish along its forward line of sight, which is the best direction for getting furthest from the attacking predator. Conversely, when the fish were presented with a robot that darted off in various directions, they had no preferred angle at which they hit a top pursuit speed. Instead, the fish that never had the chance to learn in which direction the roboprey would take off accelerated the hardest and hit their fastest speeds when they were beside the roboprey. In addition, the attacking fish slowed as the victim moved toward them. No matter how unpredictable the roboprey's evasive strategy, the predatory fish were always able to outmanoeuvre it.Blue acara cichlid fish are intelligent enough to adapt to any unpredictable behaviour that their prey may have, although they pursue at slower speeds than fish chasing prey that always escaped at the same angle. However, acceleration rather than approach speed allows the predatory blue fish to capture their prey. This means that small guppies might be unable to evade their big bright blue nemeses. Who knows, maybe blue acara fish are the guppy's equivalent of our great white shark under-the-sea nightmare.

Habitat suitability models of five keynote Bulgarian Black Sea fish species relative to specific abiotic and biotic factors

Over the past few years, predicting species spatial distributions has been recognized as a powerful tool for studying biological invasions in conservation biology and planning, ecology, and evolutionary biology. Species spatial distribution models (SDMs) are used extensively for assessing the effects of changes in habitat suitability, the impacts of climate change, and the realignment of the existing conservation priorities. SDMs relate known patterns of species occurrences to a specific set of environmental conditions. Accordingly, we have used MaxEnt SDM tool in order to provide habitat suitability models of 5 keynote fish species: European sprat (Sprattus sprattus L.), red mullet (Mullus barbatus, L.), horse mackerel (Trachurus mediterraneus, L.), bluefish (Pomatomus saltatrix, L.) and whiting (Merlangius merlangus, L.), inhabiting the Bulgarian region of the Black Sea. Presence-only (PO) data collected by pelagic surveys performed between 2017 and 2019 was further utilized to link known species occurrence localities with selected abiotic factors, such as surface sea temperature and salinity, dissolved oxygen, and speed of currents. Biotic interactions were also considered for fitting the patterns of habitat suitability models. The SDMs, obtained from the present research study, prove to have satisfactory predictive accuracy to be further implemented for conservation measures and planning, stock management policy-making, or ecological forecasting.

Under the radar: co-introduced monogeneans (Polyopisthocotylea: Gastrocotylinea) of the invasive fish Scomberomorus commerson in the Mediterranean Sea.

The Levant Basin is in many ways the world's most invaded marine ecosystem owing to the existence of the man-made Suez Canal. The invasion of free-living organisms through this pathway is increasingly documented and monitored in the past two decades, and their ecological impact recognized. Nonetheless, while tremendous scientific effort is invested in documenting introduced fishes, co-introduction events of these fishes and their parasites have drawn relatively little interest. In our research, we examined the presence of gill parasites (Monogenea) on the invasive narrow barred Spanish mackerel Scomberomorus commerson which has been known in the Mediterranean Sea for 80years. The gills of S. commerson supported numerous, relatively large monogeneans (Monogenea: Gastrocotylinea), reaching prevalence levels of 100% with a mean intensity of ~ 80 worms per host. Using an integrated molecular and morphological approach, four gastrocotylinean species were identified: Gotocotyla acanthura, Cathucotyle cathuaui, Pricea multae, and Pseudothoracocotyla ovalis. Two species, C. cathuaui and P. ovalis, are reported here for the first time from the Mediterranean. Sequences of the 28S rRNA gene of G. acanthura from native hosts, Pomatomus saltatrix and Trachinotus ovatus, differed from individuals collected from S. commerson by 1.8%. We therefore suggest that the taxonomic status and distribution of G. acanthura should be revisited, and we recommend an integrated approach as essential to accurately detect co-introductions.

Tracking Changes in Fish Diversity in the South-Eastern Adriatic Sea (Albania) Based on Local Ecological Knowledge

Abstract Evidence from the last two centuries has identified changes in the biodiversity of the Mediterranean basin triggered by the arrival of new species. Compared to the central and northern areas, the southern part of the Adriatic Sea, specifically the Albanian coast, has been less studied. The aim of this study is to evaluate the prevalence of new/non-native fish species on the north Albanian coast in order to provide the first data on their presence. Data collection was carried out from March to August 2019 using LEK (Local Ecological Knowledge) protocol in five different locations along the northern part of the Albanian coast. The research followed a predefined methodology previously successfully applied in different countries of the Mediterranean basin by using a semi-structured questionnaire. During this study, 9 new and non-native species were recognized by the fishers, while only 5 of them have shown an evident abundance increase based on their respective catches in recent years. Results suggest that some of the analyzed species, such as blue crab Callinectes sapidus and bluefish Pomatomus saltatrix, represent important members of the fish fauna in north Albania coastal waters (including the lagoons). Future studies regarding the assessment of their impact and management strategies are highly recommended.