Bluefish Research Articles

Reduced exploitation is associated with an altered sex ratio and larger length at maturity in southwest Pacific (east Australian) Pomatomus saltatrix

Pomatomus saltatrix is an important recreational fishing species with seven major populations worldwide. The reproductive biology of the southwest Pacific Ocean (east Australian) population is uncertain, with both an extended spawning and multiple spawning periods previously hypothesised. Here we demonstrate an altered sex ratio biased towards females and a larger length at 50% maturity (L50) compared to those recorded for the population 40 years ago, before comprehensive management strategies were implemented. We also report a second, previously undescribed, late-summer spawning event which was identified by analysing patterns in a gonadosomatic index across the whole population and an historical larval fish database. P. saltatrix are capable of spawning multiple times per season with estimates of batch fecundity ranging from 99,488 to 1,424,425 eggs per fish. When combined with the length frequency distribution of the population, the majority of eggs (64%) were shown to be produced by fish ≤40 cm fork length (FL). L50 was estimated at 30.2 and 31.5 cm FL for male and female P. saltatrix respectively, 4 cm larger than 40 years ago. The sex ratio of the population was found to have significantly shifted over the last 40 years from an equal sex ratio to a female dominated population (1.58 females:1 male). These dramatic alterations to the sex ratio and L50 highlights the value of monitoring the reproductive biology of exploited fish populations to ensure that management plans remain appropriate.

The pursuit strategy of predatory bluefish ( Pomatomus saltatrix).

A predator's ability to capture prey depends critically on how it coordinates its approach in response to a prey's motion. Flying insects, bats and raptors are capable of capturing prey with a strategy known as parallel navigation, which allows a predator to move directly towards the anticipated point of interception. It is unclear if predators using other modes of locomotion are employing this strategy when pursuing evasive prey. Using kinematic measurements and mathematical modelling, we tested whether bluefish ( Pomatomus saltatrix) pursue prey fish ( Fundulus heteroclitus) with parallel navigation. We found that the directional changes of bluefish were not consistent with this strategy, but rather were predicted by a strategy known as deviated pursuit. Although deviated pursuit requires few sensory cues and relatively modest motor coordination, a comparison of mathematical models suggested negligible differences in path length from parallel navigation, largely owing to the acceleration exhibited by bluefish near the end of a pursuit. Therefore, the strategy of bluefish is unlike flying predators, but offers comparable performance with potentially more robust control that may be well suited to the visual system and habitat of fishes. These findings offer a foundation for understanding the sensing and locomotor control of predatory fishes.

Feeding habits during migration of the Atlantic bonito Sarda sarda (Bloch, 1793) to the Black Sea

ABSTRACTInformation about food web dynamics is crucial for the success of ecosystem-based management. In order to collect such information, it is necessary to establish the dietary contents of species in the food chain. In this study, the diet of Atlantic bonito Sarda sarda (Bloch, 1793), one of the most important species in the Black Sea ecosystem, has been examined. The aim of this study was to investigate the prey preferences of Atlantic bonito over an eleven-year period during their feeding migration to the Black Sea. Sampling was carried out by commercial purse seine and gill nets along the Turkish Black Sea coast during migration of the Atlantic bonito from 2005 to 2016. Stomach contents were identified to the lowest possible taxonomic level. Atlantic bonito dietary composition was analyzed by fishing season, sex and size classifications. Results revealed a Vacuity Index value (V %) of 67% while 33% of individuals sampled had at least one prey species in their stomach content. Since S. sarda predominantly feed on small fish species, stomach contents contained mainly Engraulis encrasicolus, Trachurus mediterraneus, Sprattus sprattus, Mullus barbatus, Gobius niger, Merlangius merlangus, Pomatomus saltatrix, Alosa immaculata, Parablennius tentacularis and small unidentified prey items (tissue particles, … etc.). The most frequent prey item was E. encrasicolus with a percentage occurrence of 94%. In conclusion, the main prey species was determined as E. encrasicolus and statistical analyses of X2 was found significant (P < 0.005) according to year, sex and size.

Morphological characteristics of otolith for four fish species in the Edremit Gulf, Aegean Sea, Turkey

Otolith morphology is important for species identification, fishery management and stock assessment. In this study, otolith (Sagitta) morphology of four fish species viz. Pomatomus saltatrix , Sarpa salpa , Trachurus trachurus , and Belone belone was investigated. The length (mm), width (mm), area (mm 2 ) and perimeter (mm) measurements of the otoliths were made and four different shape indices, including form factor (F F ), aspect ratio (A R ), roundness (R D ) and circularity (C I ) were calculated. In addition, relationships between total fish length and otolith morphology were investigated. Measurements of sagittal otoliths of four species were obtained by image analysis using tri-ocular microscope. Based on the results, the morphometric measurements and four examined shape factors of otolith varied among species. Coefficients of correlations (r) between total fish length and otolith morphology and otolith length-otolith morphology were generally highly significant ( P <0.05) for studied fishes. The results show that the shape indices were significantly different in analyzed species even they indicated a similar pattern with maximal otolith length. These data provide information for species identification using sagittal otoliths in the fossils and diets of fish predators and also will contribute to the region's sustainable fisheries management.

Introduction: Combinations

IntroductionCombinations Claudia Nelson That the process of looking at separate things together—comparing, contrasting, considering from different angles—teaches us is a fundamental premise even of books for the very young. “One fish / two fish / red fish / blue fish,” begins a classic work by Dr. Seuss, continuing, “Black fish / blue fish / old fish / new fish. / This one has / a little star. / This one has a little car. / Say! what a lot / of fish there are” (n. pag.). And while the two blue fish in the quoted passage may well be a single fish pictured twice (Seussian style is such that it’s hard to make this call), context matters: the blue fish doesn’t look quite the same when it’s with the black fish as it did with the red fish, and in the next double-page spread it appears still more changed by the company of the “glad” fish versus that of the “very, very bad” fish. Enumerating the range of types that makes up that “lot / of fish” invites the young child not only to learn to recognize the word “fish” on the page but also to take pleasure in difference by thinking about what makes each creature special. Significantly, this cognitive exercise requires that the fish be presented as a group. In their different ways, the articles in this issue draw our attention to the value of considering combinations. We begin with LuElla D’Amico’s “The Journey to American Womanhood: Travel and Feminist Christian Rebellion in Susan Warner’s The Wide, Wide World and Martha Finley’s Elsie’s Girlhood,” which offers the combination not only of two nineteenth-century sentimental novels that share key plot elements (indeed, as D’Amico notes, Finley’s novel implicitly acknowledges its debt to Warner’s earlier best seller by identifying the latter as a text that entrances Elsie) but also of the concepts of travel and rebellion. Warner’s and Finley’s girl protagonists both journey and rebel within socially acceptable limits; they move from one family member to another and assert their right to self-determination in ways that clearly indicate their obedience to God’s authority. By examining these two texts in combination, D’Amico establishes that the way in which they invite readers to feel, and to value, “a sense of mobility within the prevailing confining paradigms” of nineteenth-century femininity is neither unique nor accidental, but part of a larger conversation within sentimental American fiction over a generation. [End Page 1] Stephanie L. Derrick’s “The Transatlantic Reception of The Chronicles of Narnia and of C. S. Lewis as a Children’s Book Author in the 1950s and 1960s, Compared” combines two reception studies of the same writer in order to argue that the very different British and American responses to Lewis’s heptalogy in the mid-twentieth century arose from cultural differences that have considerable significance for the history of children’s publishing. Whereas esteemed Victorian writers from Charles Dickens to W. M. Thackeray to Robert Browning produced works for young readers, the failure of many members of the twentieth-century British “literary elite” to follow this lead helped to prompt Lewis to assist in filling the gap. Yet in part because British critics were slower than their US counterparts to consider children’s literature worthy of serious notice, the Narnia books met with a less positive response in their homeland than they did across the Atlantic. Derrick’s investigation provides a case study in the value of considering the larger social contexts that participate both in the creation of youth literature and in how it is read by adult literary gatekeepers. In this issue’s third article, “Death in Signifiers: Words and Pictures in Three International Picture Books,” Newton Freire Murce Filho takes as his source texts a Canadian, a Brazilian, and a Portuguese picture book dealing with the aftermath of a grandparent’s death. Building upon Perry Nodelman and Mavis Reimer’s point that “a picture book contains at least three stories. There is the one told by the words, the one implied by the pictures, and the one that results from the combination of the other two” (qtd...

Fish Culture and Blue Fish in the Civilization of Bosphorus

The nostalgic concept of “Bosphorus Civilization” reflects a time period, from the time in which 17th Century Ottoman era Istanbul that people enjoyed a luscious lifestyle, to the time Second World War young Turkish Republic did not take in war but experimented its difficulties. In this period which lasted approximately 250 years, “Fish Culture” did exist as a reflection of daily life memories and “Blue Fish” was a major part of this culture. In this work, dynamics of social group will be handled through a historic perspective, in a chapter where Bosphorus-style Istanbul life was formed. The life-style and social structure formed around “Blue Fish” will be relayed through literary texts (Ahmet Hamdi Tanpınar, Abdülhak Şinasi Hisar) and memories (Asaf Muammer, Ali Pasiner). Günümüzde nostalji olarak anımsanan “Boğaziçi Medeniyeti” kavramı, içinde yaşam biçiminin de yansıdığı İstanbul’un 17. yüzyıl Osmanlı döneminden; genç Türk Cumhuriyeti’nin katılmasa da sıkıntılarını yaşadığı İkinci Dünya Savaşı yıllarına kadar süren bir zaman dilimidir. Yaklaşık 250 yıl süren bu dönemde günlük yaşamın belleklerdeki karşılığında “Balık Kültürü” ve bu kültürün başrolünde de lüfer yer alırdı. Bu çalışmada, tarihsel bir perspektif içinden İstanbul yaşamının Boğaziçi’nde şekillenen bölümünde lüfer balığı çevresindeki sosyal grubun dinamikleri ele alınacak, lüfer balığı çevresinde oluşan yaşam biçimi ve sosyal yapı, edebi metinler (Ahmet Hamdi Tanpınar ve Abdülhak Şinasi Hisar) ve anılardaki (Asaf Muammer ve Ali Pasiner) anlatılarından yararlanılarak aktarılacaktır.

Probabilistic analytical modelling of predator-prey interactions in fishes.

Predation is a fundamental interaction between species, yet it is largely unclear what tactics are successful for the survival or capture of prey. One challenge in this area comes with how to test theoretical ideas about strategy with experimental measurements of features such as speed, flush distance and escape angles. Tactics may be articulated with an analytical model that predicts the motion of predator or prey as they interact. However, it may be difficult to recognize how the predictions of such models relate to behavioural measurements that are inherently variable. Here, we present an alternative approach for modelling predator-prey interactions that uses deterministic dynamics, yet incorporates experimental kinematic measurements of natural variation to predict the outcome of biological events. This technique, called probabilistic analytical modelling (PAM), is illustrated by the interactions between predator and prey fish in two case studies that draw on recent experiments. In the first case, we use PAM to model the tactics of predatory bluefish ( Pomatomus saltatrix) as they prey upon smaller fish ( Fundulus heteroclitus). We find that bluefish perform deviated pure pursuit with a variable pursuit angle that is suboptimal for the time to capture. In the second case, we model the escape tactics of zebrafish larvae ( Danio rerio) when approached by adult predators of the same species. Our model successfully predicts the measured patterns of survivorship using measured probability density functions as parameters. As these results demonstrate, PAM is a data-driven modelling approach that can be predictive, offers analytical transparency, and does not require numerical simulations of system dynamics. Though predator-prey interactions demonstrate the use of this technique, PAM is not limited to studying biological systems and has broad utility that may be applied towards understanding a wide variety of natural and engineered dynamical systems where data-driven modelling is beneficial.

EVALUATION OF HEAVY METALS CONCENTRATION DYNAMICS IN FISH FROM THE BLACK SEA COASTAL AREA: AN OVERVIEW

Contamination of the marine environment induced by metals has risen in recent years due to the global population increase and it affects the aquatic ecosystem via food chain. The current paper aims to present information regarding the heavy metals accumulation in fish from the Black Sea West, South and South-East coastal areas. Therefore, various databases were revised and the relevant information was centralized, in order to obtain a clear view on the concentration dynamics and accumulation tendency of several heavy metals, as follows: Pb, Cd, Fe, Zn, Cu, Hg, Ni, Cr and As. As a conclusion to this research, we can state that the highest concentrations of heavy metals in fish meat was encountered in case of red mullet (Mullus barbatus, Linnaeus, 1758), followed by bluefish (Pomatomus saltatrix, Linnaeus, 1766). The upwarding scale of heavy metals concentration, reported in the analysed studies was found as follows: Cr < Ni < Hg < Cd < Pb < As < Cu < Fe < Zn. Both West part (Romanian and Bulgarian marine coastal areas) and Central South part of the Black Sea (Turkish marine coastal area, represented by the perimeter situated between the Kizilirmak and Ye.ilirmak rivers) have proven to be the most polluted in terms of heavy metals accumulation in fish meat.

Relationships between fish and otolith dimensions of Pomatomus saltatrix (Linnaeus, 1766) (Perciformes: Pomatomidae) in southeastern Brazil

ABSTRACT The bluefish, Pomatomus saltatrix (Linnaeus, 1766), was used as a species-specific model to study morphometric relationships between otolith size and relative growth variables. Length-weight relationships between Otolith (Length-OL, Height-OH, and Weight-OW) and fish measurements (Total Length-TL and Total Weight-TW) were determined for fishes captured monthly during the year 2015 off the southeastern coast of Brazil. The ANCOVA and Kruskal-Wallis analysis did not indicate significant differences in the relative growth constants between sexes and length frequency distributions (p &gt; 0.05). The condition factor also did not present significant differences between sexes, and right and left otolith measurements (p &gt; 0.05). A total of 398 specimens were sampled: TL = 43.6-67.0 cm, TW = 365-2400 g, OL = 9.65-15.25 mm, OH = 3.65 - 5.45 mm and OW = 0.03-0.11 g. The LWR for grouped sexes was TW = 0.050TL2.55 and otoliths OW = 6.17E-05OL2.59. The best adjustments were TL vs OL (r2 = 0.90); OL vs OW (r2 = 0.90); TW vs OW (r2 = 0.81); and TW vs OL (r2 = 0.80). These results showed that such relationships are helpful tools for predicting the fish size and weight from otoliths, which may be used in food habits and paleontology studies, and other fisheries management applications.

Monitoring of weekly catch per unit effort (CPUE) and some biological features of bluefish (Pomatomus saltatrix Linnaeus, 1766) captured from southern Black Sea coasts of Turkey

In this study, changing of catch per unit effort (CPUE) and length composition of bluefish (Pomatomus saltatrix Linnaeus, 1766) caught in southern Black Sea was monitored during the period of 8 weeks in October and November 2012. A total of 2255 kg bluefishes were captured by pelagic trawl at the end of the 32 hauls. The length-weight relationships of bluefish were established as W=0.0037L3.3067 (positive allometric growth). The catch per unit effort (CPUE) and mean length were fixed as 14.43 kgh-1 and 17.5±0.03 cm, respectively. Differences between CPUE values of each weeks were found statistically significant (P&amp;lt;0.05). The highest and lowest mean total lengths of bluefish were determined 18.9±0.08 cm (October) and 16.2±0.10 cm (November) respectively. It is determined that changing in size composition of the caught fishes is depending on time. Also, it can be expressed that fishing period affects catch per unit effort in bluefish fisheries.

The influence of ontogenetic diet variation on consumption rate estimates: a marine example

Consumption rates are the foundation of trophic ecology, yet bioenergetics models used to estimate these rates can lack realism by not incorporating the ontogeny of diet. We constructed a bioenergetics model of a marine predatory fish (tailor, Pomatomus saltatrix) that incorporated high-resolution ontogenetic diet variation, and compared consumption estimates to those derived from typical bioenergetics models that do not consider ontogenetic diet variation. We found tailor consumption was over- or under-estimated by ~5–25% when only including the most common prey item. This error was due to a positive relationship between mean prey energy density and predator body size. Since high-resolution diet data isn’t always available, we also simulated how increasing dietary information progressively influenced consumption rate estimates. The greatest improvement in consumption rate estimates occurred when diet variation of 2–3 stanzas (1–2 juvenile stanzas, and adults) was included, with at least 5–6 most common prey types per stanza. We recommend increased emphasis on incorporating the ontogeny of diet and prey energy density in consumption rate estimates, especially for species with spatially segregated life stages or variable diets. A small-moderate increase in the resolution of dietary information can greatly benefit the accuracy of estimated consumption rates. We present a method of incorporating variable prey energy density into bioenergetics models.

Striped Bass and Atlantic Menhaden Predator–Prey Dynamics: Model Choice Makes the Difference

AbstractA version of multispecies virtual population analysis (MSVPA‐X) had been the sole means of evaluating predation mortality by Striped Bass Morone saxatilis, Bluefish Pomatomus saltatrix, and Weakfish Cynoscion regalis on Atlantic Menhaden Brevoortia tyrannus during 1982–2008. Simplified models may offer a different view of predation, so we developed alternative estimates of predation mortality on Atlantic Menhaden with a simpler biomass dynamic predator–prey (Steele–Henderson or S–H) model. Strongly contrasting predictions of the importance of predation on age‐1+ Atlantic Menhaden, particularly Striped Bass predation, emerged between the MSVPA‐X and the S–H model. Striped Bass selected mostly age‐0 and age‐1 Atlantic Menhaden when modeled by MSVPA‐X, even though large Striped Bass (&gt;40% of biomass after the mid‐1990s) were capable of consuming all ages. Consumption of Atlantic Menhaden by Striped Bass in the S–H model was drawn from aggregated age‐1+ biomass. Combined predation mortality from Striped Bass, Bluefish, and Weakfish was well below fishing mortality for all but the earliest years in the MSVPA‐X but was greater than or equivalent to fishing mortality throughout most of the S–H model time series. Striped Bass were a relatively minor source of Atlantic Menhaden predation mortality with the MSVPA‐X but were the major source since the late 1990s in the S–H model. Annual estimates of Atlantic Menhaden biomass consumed per unit of Striped Bass biomass from the S–H model were roughly five times higher than MSVPA‐X estimates and more consistent with estimates from bioenergetics models and trends of Striped Bass well‐being indicators (tag‐based natural mortality rates and weight at age). Use of an alternative S–H model provided a more complete picture of the potential range of predation pressure.

Lepocreadiidae Odhner, 1905 and Aephnidiogenidae Yamaguti, 1934 (Digenea: Lepocreadioidea) of fishes from Moreton Bay, Queensland, Australia, with the erection of a new family and genus

Digeneans of the lepocreadioid families Lepocreadiidae Odhner, 1905 and Aephnidiogenidae Yamaguti, 1934 from Moreton Bay, off southern Queensland, Australia, are recorded, along with the erection of a new family, Gibsonivermidae. Molecular data were generated for all representatives of these families collected during this study and a phylogram for members of the superfamily was generated based on the partial 28S rDNA dataset, placing these species in context with those previously sequenced. This phylogenetic analysis demonstrates that the monotypic Gibsonivermis Bray, Cribb & Barker, 1997 is isolated from all other lepocreadioids and supports the erection of Gibsonivermidae n. fam., which is defined morphologically, based particularly on the uniquely elongated male terminal genitalia, the distribution of the uterus in the forebody and the presence of a uroproct. Mobahincia teirae n. g., n. sp. is reported from Platax teira (Forsskål) in Moreton Bay and off Heron Island and New Caledonia. Recognition of this new genus is based on molecular results and the combination of caeca abutting the posterior body wall and the lack of an anterior body scoop or flanges. The following lepocreadioid species are reported from Moreton Bay for the first time: Bianium arabicum Sey, 1996 in Lagocephalus lunaris (Bloch & Schneider), Diploproctodaeum cf. monstrosum Bray, Cribb & Justine, 2010 in Arothron hispidus (Linnaeus), Multitestis magnacetabulum Mamaev, 1970 and Neomultitestis aspidogastriformis Bray & Cribb, 2003 in Platax teira and Opechona austrobacillaris Bray & Cribb, 1998 in Pomatomus saltatrix (Linnaeus). Bianium plicitum (Linton, 1928) is reported from Torquigener squamicauda (Ogilby) for the first time. Sequences of newly collected specimens of Austroholorchis sprenti (Gibson, 1987) indicate that the species forms a clade with other members of the Aephnidiogenidae, agreeing with its morphology. The phylogenetic status of all newly sequenced species is discussed.

Citizen science records describe the distribution and migratory behaviour of a piscivorous predator, Pomatomus saltatrix

Abstract Understanding the processes driving species distributions is a key question in ecology, yet obtaining pertinent data for many species can be challenging. Tag-recapture data from voluntary recreational fisheries programmes is an undervalued citizen science data resource and can provide valuable observation records for data-poor species. Here, we highlight the utility of such data by compiling four tag-recapture datasets (n = 20 878 tags) to describe the movements and distribution of a piscivorous predator, tailor Pomatomus saltatrix, with respect to their environment. We compared species distribution models that explored a trade-off between temporal duration and spatial extent. Both models revealed sea surface temperature (SST) was an important factor in describing the distribution and density of tailor. However, the model with broader spatial extent indicated a non-linear response to SST, peaking at 21.5°C, while the model with temporal longevity showed a linear SST response. This disjunct showcases the importance of building models across an adequate geographic extent to ensure covariate responses are not truncated. This is the first study to comprehensively describe the distribution and migrations of adult tailor across their eastern Australian distribution. The results are discussed in light of ocean warming along eastern Australia, and the subsequent implications for using tag-recapture data in fisheries management.

Food neophobia, Mediterranean diet adherence and acceptance of healthy foods prepared in gastronomic workshops by Spanish students.

food neophobia can affect dietary variety and hedonic acceptance due to rejection of healthy foods. to evaluate the impact of dietary neophobia on adherence to the Mediterranean diet and on the hedonic acceptance of healthy foods made in gastronomic workshops by schoolchildren. descriptive cross-sectional study of Primary (8-11) and Secondary (12-18) schoolchildren from Murcia, Spain, participating in gastronomic workshops, where two recipes were prepared and tasted (vegetables + blue fish and fruits). Food neophobia (FN) and adherence to the Mediterranean diet (KIDMED) were identified and each participant assessed the acceptance of each recipe using a hedonic scale (seven points). a total of 1,491 students (49.5% girls) participated in the study; 13.5% were neophobic and 61.1% presented optimal diet quality. A linear inverse relationship between the degree of neophobia and the quality of the diet (ρ[rho] = -0.31, p = 0.001) was found. High adherence to the Mediterranean diet was associated with lower neophobia and better hedonic scores, compared to intermediate or low adhesions (p < 0.0001). Neophobic schoolchildren presented significantly worse results in vegetable consumption, especially at the Secondary level, and in the acceptance of healthy preparations (p < 0.05). A good acceptance of the prepared preparations was associated with the usual adequate consumption of fruits, vegetables, fish and legumes. food neophobia affects the adherence to the Mediterranean diet and the acceptance of healthy foods elaborated in gastronomic workshops by Spanish schoolchildren.

Hook Selectivity for Bluefish (Pomatomus saltatrix Linneaus, 1766) in Gallipoli Peninsula and Çanakkale Strait (Northern Aegean Sea, Turkey)

Bu çalışma, Gelibolu Yarımadası ve Çanakkale Boğazı’ndaki lüfer balığı (Pomatomus saltatrix Linnaeus, 1766) avcılığında kullanılan olta iğneleri seçiciliklerini belirlemek için, 2006-2009 balıkçılık sezonunda, lüfer göç zamanı olan Eylül, Ekim ve Kasım ayları arasında gerçekleştirilmiştir. Lüfer balıklarının avcılığı 1, 1/0, 2/0, 3/0, 4/0 numara iğneler ile gerçekleştirilmiş ve 1210 adet lüfer balığı yakalanmıştır. En fazla birey 2/0 numara iğne ile (344 birey, % 20,43) en az birey ise 1 numaralı iğne ile (35 birey, % 2,89) elde edilmiştir. Farklı iğne numaraları ile avlanan lüfer balığının boy frekans dağılımları kullanılarak uygulanan SELECT metoduna göre en uygun model, normal scale model olarak saptanmıştır. Normal scale modele göre kullanılan iğne büyüklükleri için hesaplanan optimum yakalama boyları (OYB) ve eğrinin genişlikleri (EG), sırasıyla, 1 no’lu iğne için 19,18 cm OYB ve 4,44 EG; 1/0 no’lu iğne için 21,88 cm OYB ve 5,07 EG; 2/0 no’lu iğne için 24,14 cm OYB ve 5,59 EG; 3/0 no’lu iğne için 27,02 cm OYB ve 6,26 EG ve 4/0 no’lu iğne için 28,19 cm OYB ve 6,53 EG’dir. Lüfer balıklarının Türkiye’deki minimum avlanma boyu 20 cm olduğu için lüfer avcılığında 2/0 numara ve daha büyük iğnelerin kullanımı önerilebilir

Sperm characters of the bucephalid digenean Prosorhynchoides arcuatus and their phylogenetic significance

The present study describes the ultrastructural organisation of the mature spermatozoon of the bucephalid digenean Prosorhynchoides arcuatus (Bucephalinae) collected from the Bluefish Pomatomus saltatrix (Teleostei: Pomatomidae) caught from the Gulf of Gabès in the Chebba (Tunisia) by means of transmission electron microscopy. The ultrastructural study reveals that the mature spermatozoon of P. arcuatus is a filiform cell which is tapered at both extremities. It exhibits the Bakhoum et al.’s type V of spermatozoon of digeneans characterised by the presence of two axonemes with the 9+‘1’ pattern of the Trepaxonemata, lateral expansion, external ornamentation of the plasma membrane located in the anterior part of the proximal region of the spermatozoon and associated with cortical microtubules, two bundles of parallel cortical microtubules with maximum number located in the anterior part of the spermatozoon, and one mitochondrion. Other characteristics are the presence of spine-like bodies, a posterior extremity containing only the nucleus, and the presence of a large amount of glycogen granules. Results of the present study are compared with the existing data in other digeneans, particularly bucephalids.

Marmara Denizi’ndeki Lüfer balığının Pomatomus saltatrix (Linnaeus, 1766) büyüme ve üreme özellikleri

This study was carried out to investigate the growth and reproductive characteristics of bluefish Pomatomus saltatrix (Linnaeus, 1766) in Marmara Sea. A total 1023 samples, collected monthly from commercial fishermen between January and December 2014, was investigated . Total length distribution of the samples varied between 12,3-47,3 cm. The length-weight relation of all sample individuals is calculated as W = 0,0107L 2,9574 . It was determined that the growth pattern was isometric ( b =3, P ˃ 0,05) by the constructed t -test. Using the age-length values , the growth equation of von Bertalanffy was calculated as L t =48,7[1-e -0,247(t+1,677) ] . Growth performance index ( ɸ ´ ) was computed as 2,757 for all specimens . The monthly values of gonad somatic index (GSI) of females indicated that spawning occurred mainly between May and August with a peak in July .

Overwinter Habitat Use, Feeding Habits and Energetics of Juvenile Bluefish in the Northern Florida Coastal Ocean

Recruitment success for juvenile fishes that take part in seasonal migrations may be dependent on the environmental conditions during the first winter of life. Juvenile bluefish (Pomatomus saltatrix) in the USA migrate from mid-Atlantic waters during the fall to overwinter in the coastal ocean of Florida and return again in the spring. Little is known regarding the recruitment dynamics and feeding ecology of juvenile bluefish at the southern edge of the species US range, particularly during winter. We examined the cohort structure, feeding habits, and lipid content of juvenile bluefish during late fall and winter in the northern Florida coastal ocean. We found that three juvenile bluefish cohorts migrated to the area at distinct temporal and spatial intervals. Abundance of juvenile bluefish was greatest during January and was dominated by the summer-spawned cohort. We first collected fall-spawned fish in January, and this was the only cohort collected by March, indicating the possibility of local spawning from a resident bluefish population. Stomach content analysis revealed that all three juvenile bluefish cohorts used the northern Florida coastal ocean to forage during the winter, and striped anchovy (Anchoa hepsetus) was the primary prey. Feeding intensity of juvenile bluefish was greatest in December and January, and their lipid content increased throughout the winter. Juvenile bluefish recruited to the coastal shelf waters of northern Florida, where the region provided this popular sportfish with distinct overwintering resources.

Relationships between total length and otolith size of bluefish Pomatomus saltatrix (Linnaeus, 1766) in the Marmara Sea of Turkey

In the present study, bluefish, Pomatomus saltatrix, was monthly collected from commercial fishing boats operating in the Marmara Sea between January and December 2014. The relationship between total length and otolith size of 346 bluefish samples were examined. Total lengths of females, males and unidentified samples were ranged from between 13.2-37.0, 12.3-34.8 and 13.0-31.6 cm, respectively. Otolith lengths were between 3.82-12.60 mm and otolith width were between 1.59-4.34 mm for all samples. It was found that there is a strong correlations between otolith length-total length (r2 =0.88) and otolith width-total length (r2 0.81).