Single Yolk Research Articles

Double yolk eggs detection using fuzzy logic.

Chicken egg products increased by 60% worldwide resulting in the farmers or traders egg industry. The double yolk (DY) eggs are priced higher than single yolk (SY) eggs around 35% at the same size. Although, separating DY from SY will increase more revenue but it has to be replaced at the higher cost from skilled labor for sorting. Normally, the separation of double yolk eggs required the expertise person by weigh and shape of egg but it is still high error. The purpose of this research is to detect double-yolked (DY) chicken eggs with weight and ratio of the egg’s size using fuzzy logic and developing a low cost prototype to reduce the cost of separation. The K-means clustering is used for separating DY and SY, firstly. However, the error from this technique is still high as 15.05% because of its hard clustering. Therefore, the intersection zone scattering from using the weight and ratio of the egg’s size to input of DY and SY is taken into consider with fuzzy logic algorithm, to improve the error. The results of errors from fuzzy logic are depended with input membership functions (MF). This research selects triangular MF of weight as low = 65 g, medium = 75 g and high = 85 g, while ratio of the egg is triangular MF as low = 1.30, medium = 1.40 and high = 1.50. This algorithm is not provide the minimum total error but it gives the low error to detect a double yolk while the real egg is SY as 1.43% of total eggs. This algorithm is applied to develop a double yolk egg detection prototype with Mbed platform by a load cell and OpenMV CAM, to measure the weight and ratio of the egg respectively.

Three-dimensional ultrasonographic features of diamniotic conjoined twins with body stalk anomaly

BackgroundSince conjoined twins were thought to be monoamniotic in the past, diamniotic conjoined twins would be improbable theoretically. Body stalk anomaly is a severe defect of the body wall, which is rare among twins. Body stalk anomaly in monochorionic diamniotic conjoined twins has never been reported prenatally so far as we know.Case presentationHere we present an extremely rare case of concordant body stalk anomaly in monochorionic diamniotic conjoined twins. Ultrasonography at 9 + 5 weeks revealed one chorionic and two amniotic cavities, close apposition of abdomen, limited movement, and common umbilical vessels. Follow-up ultrasonography at 11 + 6 weeks and 13 + 2 weeks showed close apposition of the lower abdominal region with cystic structures and a small bowel-like mass between the two fetuses. Three-dimensional ultrasonography assisted in observing the entire appearance of both twins in earlier first trimester, including amnioticity, conjoined region and umbilical vessels. We attribute this diamniotic conjoined twin in our case to the fusion theory. A single yolk sac was observed, challenging the idea that yolk sac number predicts amnionicity. Identification of single yolk sac and its allantois may form a common body stalk during this fusion, leading to concordant body stalk anomaly in monochorionic diamniotic twins.ConclusionsOur case may provide important insights into both ultrasonographic features and embryogenesis of this extremely rare anomaly.

Twins at Conspicuously Different Developmental Stages in a Turtle Egg.

One-egg twins, in general, initiate embryonic development at the same time, and their developmental stages proceed in parallel. Here we report a rare case of the embryonic development of the red-eared slider turtle, Trachemys scripta, in which twins at conspicuously different developmental stages developed on a single yolk. One of the twins appeared to have developed at the normal developmental rate, whereas the development of the other was markedly delayed, despite the absence of any overt anomalies. This observation suggests uncoupled or fully independent differential regulation of embryonic development from either a single or, more likely, two distinct pluripotent blastoderms sharing the same yolk and same environmental conditions.

The phenomenon of the monovular twinning in the endangered zatorska goose

The phenomenon of multiple embryos in birds and other oviparous vertebrates is very rare and thus poorly studied. Some populations of wild birds or lines of poultry, including the zatorska goose, may be particularly predisposed to developing monovular twin embryos (MTE). The aim of the study was to investigate the frequency of single yolk twin embryos in the zatorska goose and to establish whether these embryos are generated as a result of polyembryony or other developmental anomalies.Embryopathological analysis, which included identification of the developmental stages of all MTEs at the time of death, was carried out on 1,955 unhatched eggs obtained from 20 pedigree breeding flocks of the zatorska goose. Post-mortem examinations revealed as many as 13 MTEs (0.66% compared to embryonated eggs) at varying developmental stages.The results of genotyping of the microsatellite loci of 7 pairs of twins demonstrated genetic similarity in 6 of them; this suggests that they developed from 1 blastoderm, while differences in 2 loci of 1 pair show that the MTE originates from 2 blastodiscs. Pedigree analysis of the MTEs does not provide evidence that predisposition toward twinning results from the genetic background. However, more frequent MTE occurrence could be seen in eggs stored for more than 8 d. It seems that embryos of the zatorska goose are more susceptible to duplication under special conditions, such as prolonged egg storage.

Prediction of Amnionicity Using the Number of Yolk Sacs in Monochorionic Multifetal Pregnancy.

The purpose of this article was to evaluate the accuracy of predicting amnionicity using the number of yolk sacs by diagnostic ultrasound examination in monochorionic (MC) multifetal pregnancies between 7 + 0 and 9 + 6 gestational weeks. A total of 97 patients with MC multifetal pregnancies underwent early ultrasound examination from 2004 to 2014 at Cheil General Hospital and Women's Healthcare Center. All patients for whom the number of yolk sacs was reported were included in this study. We compared the number of yolk sacs with amnionicity confirmed by an intertwine membrane. Overall, there was a 9.3% (9 cases) discrepancy in number of yolk sacs and amnionicity (4.3% for monochorionic diamniotic, 36.4% for monochorionic monoamniotic, and 33% for monochorionic triamniotic). Among the 9 cases with discrepancies, 4 cases with 2 yolk sacs were confirmed as monoamniotic pregnancies and 4 MC twin pregnancies showing a single yolk sac were diagnosed as diamniotic twin pregnancies. One case with 2 yolk sacs was identified as a triamniotic triplet pregnancy. In 9.3% of MC gestations, the number of yolk sacs was not correlated with the number of amnions in our study. To determine amnionicity in MC multifetal pregnancies, we recommend careful evaluation not of the number of yolk sacs but the presence or absence of intertwine dividing membrane after 8 gestational weeks.

Co3O4 Nanospheres Embedded in a Nitrogen-Doped Carbon Framework: An Electrode with Fast Surface-Controlled Redox Kinetics for Lithium Storage

Herein, we develop a Co3O4-based anode material with a hierarchical structure similar to that of a lotus pod, where single yolk–shell-structured Co3O4@Co3O4 nanospheres are well embedded in a nitrogen-doped carbon (N–C) conductive framework (Co3O4@Co3O4/N–C). This distinctive architecture contains multiple advantages of both the yolk–shell structure and conductive N–C framework to improve the Li ion storage performance. Especially, the doping of the N atom in N–C increases the interaction between the carbon and adsorbents, which is confirmed by the theoretical calculations in this work, making the carbon framework much more electrochemically active. As a result, the Co3O4@Co3O4/N–C exhibits fast surface-controlled kinetics, which corroborate the high counterion mobility and the ultrafast electron-transfer kinetics of the electrode. Due to these synergetic effects, desired capacity stability (1169.6 mAh g–1 at 200 mA g–1 after 100 cycles) and superior rate performance (633.4 mAh g–1 at 10 A g–1) have been realized in this Co3O4@Co3O4/N–C electrode.

Yolk sac number does not predict reliably amnionicity in monochorionic twin pregnancies: a case of a monochorionic monoamniotic twin pregnancy with two distinct yolk sacs on early first‐trimester ultrasound

The dramatic increase in multiple births over the past 30 years has made multiple pregnancy one of the most common high-risk conditions encountered by obstetricians. In North America, the rate of multiple pregnancy has increased by 50–70% and this is largely attributed to advanced reproductive technologies1, 2. In monochorionic multiple gestations the determination of amnionicity is technically difficult to perform based both on the relatively late appearance of the amnion on ultrasound, typically between 8 and 10 weeks, along with the thin nature of the membrane. Previous studies have suggested that on early first-trimester ultrasound, monochorionic monoamniotic (MCMA) twin pregnancies can be reliably characterized by the presence of a single yolk sac and monochorionic diamniotic (MCDA) twins can be reliably characterized by the identification of two yolk sacs3. Accurate and early prenatal ultrasound diagnosis of amnionicity, along with enhanced prenatal/neonatal care, has been shown to decrease the mortality rates of MCMA twins from 50% to 10–20% in more recent years2. Recently, the accuracy of using yolk sac number as a means of predicting amnionicity has been challenged4-6. In a recent series of 22 cases of monochorionic multiple gestations, Shen et al.4 revealed that 85% of the 20 cases of MCDA gestations had two yolk sacs and that 15% were characterized by only a single yolk sac; a single case of MCMA was identified in this series and one yolk sac was seen. In 2010, three cases of MCMA twins characterized by the presence of two yolk sacs on first-trimester ultrasound were reported5, 6. Here, we present a fourth case of MCMA twins in which early first-trimester ultrasound demonstrated the presence of two yolks sacs with confirmed monoamnionicity in the late first trimester. A 31-year-old G1P0 Caucasian woman presented at a private fertility clinic for intrauterine insemination with donor sperm for social reasons. A transvaginal ultrasound examination (E8, GE Medical Systems, Zipf, Austria) was performed at 7 + 0 weeks for confirmation of intrauterine pregnancy. The 7-week ultrasound clearly demonstrated two distinct fetal poles and two separate yolk sacs. The crown–rump length measurements, of 7.6 mm and 7.9 mm, were consistent with the expected size for each fetal pole, and cardiac activity was present in both. The pregnancy was considered to be MCDA twin gestation at this point in time, based on the presence of two yolk sacs (Figure 1). At 9 + 2 weeks a single amniotic sac was observed with the absence of a dividing intergestational membrane (Figure 2). At 12 + 2 weeks of gestation, ultrasound demonstrated the absence of a dividing membrane between the fetuses (Figure 3). Power Doppler at this time revealed umbilical cord entanglement, confirming the diagnosis of a MCMA twin gestation (Figure 4). Transvaginal ultrasound at 7 weeks' gestation demonstrated two yolk sacs in a monochorionic twin pregnancy. Repeat transvaginal ultrasound at 9 + 2 weeks revealed a single amniotic sac and the absence of an intergestational membrane. Transvaginal ultrasound at 12 + 2 weeks demonstrated the absence of a dividing membrane. Transvaginal ultrasound at 12 + 2 weeks verified umbilical cord entanglement. This case highlights the close proximity in the sequence of development of the yolk sac and amnion and emphasizes our lack of understanding of the temporal differentiation of these structures. The almost simultaneous development of the yolk sac and amnion could explain these most recent findings that yolk sac number does not always correlate with amnionicity in monochorionic gestations. Yolk sac number should no longer be considered a reliable means of diagnosing amnionicity on early first-trimester ultrasound. The consequent clinical implications are an enhanced focus on the diagnosis of amnionicity based on the presence or absence of the intergestational amnion and the visualization of umbilical cord entanglement7, 8.

Three‐dimensional sonograph of a monochorionic diamniotic triplet pregnancy

A monochorionic diamniotic triplet pregnancy was diagnosed by sonographic scan at 9 weeks of gestation. The three embryos appeared to share the same trophoblast, with two of them sharing the same amniotic sac. The two amniotic sacs were divided by a thin membrane, with no chorionic projection within it, and each amniotic sac presented a single yolk sac. Only few cases of nontrichorionic-triamniotic triplets have been reported in the literature. Although the diagnosis was reached using the two-dimensional ultrasound, the complementary use of three-dimensional ultrasound helped in confirming the diagnosis, and in offering the couple an adequate counseling.

OP19.05: Monochorionic monoamniotic twin pregnancies with two yolk sacs may not be a rare finding: a report of two cases

Exact determination of amnionicity is a major issue for clinical management of monochorionic twin pregnancies, due to quite high risk of perinatal mortality and morbidity in monochorionic monoamniotic (MM) twins. Counting the number of yolk sacs is believed to be good indicator of amnionicity in the early first trimester, as the number of yolk sacs is alleged to be equal to amnionicity order in both MM and monochorionic diamniotic (MD) twin pregnancies. However, the accuracy of the relationship between number of yolk sacs and amnionicity has recently been called into question in MD twin pregnancies. To the best of our knowledge, no previous reports have shown two yolk sacs in MM twin pregnancies. We report 2 cases of MM twins with two yolk sacs on first trimester ultrasonography, and confirmed monoamnionicity showing umbilical cord entanglement and postnatal placental examination. Pregnant courses of both cases were uneventful, and elective Cesarean sections were performed at 33 + 2 and 34 + 4 weeks of gestation, respectively. All four babies showed good growth without any complications by 2 years old and 4 months old in each. Amnionicity of both cases were also confirmed MM twin placenta after postnatal gross examinations. In conclusion, two yolk sacs in cases of MM twin pregnancy may not be a rare finding and can be expected to show equivalent outcomes to MM twin pregnancy with a single yolk sac. Detection of two yolk sacs on ultrasound examination in monochorionic twin pregnancy does not rule out monoamnionicity. The possibility of monoamnionicity must still be suspected when two yolk sacs are detected early in the first trimester ultrasound examination for monochorionic twin pregnancies.

Yolk-Sac Number in Monoamniotic Twins

It has been accepted practice to use yolk-sac number to predict amnionicity in twin pairs. Two yolk sacs in a single chorionic sac were thought to confirm diamniotic pregnancy, and a single yolk sac with two fetal poles was thought to indicate monoamniotic twins. Thus, basic ultrasonography could confirm amnionicity early in pregnancy and avoid invasive testing or the more difficult tasks of demonstrating the absence of a dividing membrane or presence of entwined cords later in the pregnancy. We present a case of monoamniotic twin gestation in which early ultrasonography confirmed the presence of two yolk sacs. Doppler showed entwined umbilical cords. After elective cesarean delivery, the twins did well in the neonatal intensive care unit and continue to thrive. Yolk-sac number does not predict amnionicity. The diagnosis of monoamniotic twins requires demonstration of entwined cords or an invasive procedure.

Monoamniotic twin pregnancy: a review of contemporary practice

Monoamniotic twins represent an uncommon manifestation of the monozygotic twinning process (1% of monozygotic twins). They are the result of ovum division beyond 8 days postconception and are characterised by a single amnion and a single yolk sac. There may be two or one (conjoined twins) embryos present. This form of twinning is notable for an increase in perinatal loss (10-15% in contemporary series of prenatally recognised cases). Congenital anomalies, umbilical cord entanglement/accidents, preterm birth and intrauterine growth restriction primarily account for this increased perinatal mortality rate. Diagnosis is most typically by ultrasound, with the inability to distinguish a dividing membrane between the fetuses the most typical feature. There are diagnostic pitfalls (oligohydramnios in one twin with closely adherent membrane) and accuracy in diagnosis is central to appropriate pregnancy management. Obstetric management protocols are based on several retrospective case series, and there is a paucity of large well-controlled studies to provide guidance in the management of monoamniotic twin pregnancies. The prevention of antepartum death from umbilical cord entanglement is one of the central management issues; however, the available techniques of antepartum surveillance have a variable performance in predicting this event.

Number of yolk sacs does not predict amnionicity in early first‐trimester monochorionic multiple gestations

To determine the relationship between amnionicity and number of yolk sacs before 11 weeks of gestation. Twenty-two cases of monochorionic multiple pregnancy were scanned before 11 weeks of gestation. There were 21 sets of twins and one of triplets. Amnionicity was determined by visualization of a dividing amniotic membrane between the gestational sacs. The number of yolk sacs was recorded and compared with the presence or absence of a dividing membrane for all fetuses. In 17/20 (85%) cases of monochorionic diamniotic twins, two yolk sacs were seen. In 3/20 (15%) cases of monochorionic diamniotic twins, a single yolk sac was seen. In the one case of monochorionic diamniotic triplets, two yolk sacs were visualized. In one case of monoamniotic twins, a single yolk sac was observed. In monochorionic pregnancies, the presence of two yolk sacs predicts diamnionicity. However, the use of the number of yolk sacs as a predictor of amnionicity may not be accurate in a small proportion of patients. The diagnosis of monoamnionicity can be made only following a careful search for a dividing amniotic membrane.

Ischiopagus conjoined twins at 9 weeks of gestation: three‐dimensional ultrasound and power Doppler findings

The incidence of conjoined twins is estimated to range from 1 in 50 000 to 1 in 100 000 births1. The most common types of conjoined twins are thoracopagus, omphalopagus and thoraco-omphalopagus1. Only about 12% are of the ischiopagus variety2, which refer to twins joined at the level of the ischium. A 30-year-old woman, gravida 2, para 1, was seen at our antenatal clinic during her 9th week of pregnancy. She denied exposure to ovulation medication prior to conception. Two-dimensional (2D) ultrasonography revealed monoamniotic twins lying face-to-face, one yolk sac (Figure 1) and two separate cardiac pulsations. The embryos were fused at the lower part of the trunk and were suspected to be twins conjoined at the level of the pelvis. Subsequently, a three-dimensional (3D) volume dataset of the embryos was acquired using transvaginal ultrasonography with power Doppler (Voluson 730 Expert, GE Medical Systems, Milwaukee, WI, USA). Vascular communication between the conjoined twins in the pubic area was accurately delineated (Figure 2). A volume dataset was acquired in the sagittal plane for subsequent analysis. The multiplanar views and surface-rendered images of the embryos were obtained to precisely delineate the level of fusion, connecting vessels and fetal contour (Figure 3). One week later, repeat scans by 3D transvaginal ultrasonography confirmed the diagnosis of conjoined twins. After counseling, the patient opted to terminate the pregnancy. After evacuation, two separate bodies and two separate upper and lower extremities were noted. The location of the conjoined site could not be identified on gross inspection of the abortus because the embryos had been destroyed during the evacuation procedure. Transvaginal two-dimensional sonography showing a single gestational sac, one yolk sac and conjoined twins lying in a mirror-image-like position. Vascular communication between the twins. This image was obtained by multiplanar analysis of the three-dimensional volume dataset acquired by transvaginal ultrasonography with power Doppler. Three-dimensional surface-rendered image showing ischiopagus twins with two normal heads, separate thorax and two separate upper and lower extremities. Early diagnosis of conjoined twins is crucial for determining subsequent management and possibly decreasing maternal morbidity (evacuation vs. hysterotomy). Specific sonographic findings of conjoined twins examined during the first trimester include inseparable fetal bodies despite manipulation of the uterus with a transvaginal probe or prolonged continuous scanning, bifid appearance of the embryo, single yolk sac3, and a single umbilical cord with more than three vessels. Recently, some reports4-8 have described early diagnosis of conjoined twins by 3D ultrasound imaging combined with power Doppler, computed tomography and magnetic resonance imaging. In this case, prenatal diagnosis of conjoined twins was established by transvaginal 2D ultrasonography and power Doppler. However, 3D imaging with surface-rendering provided clearer images of the characteristic features of ischiopagus twins and helped the parents to understand the complex anomalies present in their fetuses. Furthermore, it improved our diagnostic confidence to provide adequate early intervention. K.-H. Fang*, J.-L. Wu*, G.-P. Yeh* , P.-H. Chou*, J.-C. Hsu*, C. T.-C. Hsieh*, * Department of Obstetrics Gynecology, Changhua Christian Hospital, Changhua, Taiwan, Department of Obstetrics Gynecology, Chung-Shan Medical University, Taichung, Taiwan

Cloning and expression of the yolk protein of the tsetse fly Glossina morsitans morsitans

Two major families of nutritional proteins exist in insects, namely the vitellogenins and the yolk proteins. While in other insects only vitellogenins are found, cyclorraphan flies only contain yolk proteins. Possible sites of yolk protein synthesis are the fat body and the follicle cells surrounding the oocyte. We report the cloning of the yolk protein of the tsetse fly Glossina morsitans morsitans, a species with adenotrophic viviparity. The tsetse fly yolk protein could be aligned with other dipteran yolk proteins and with some vertebrate lipases. In contrast to the situation in most fly species, only a single yolk protein gene was found in the tsetse fly. Northern blot analysis showed that only the ovarian follicle cells, and not the fat body represents the site of yolk protein synthesis.

P12.29: Sonographic imaging of monochorionic monoamniotic twin pregnancy by the finding of a single yolk sac

P12.29: Sonographic imaging of monochorionic monoamniotic twin pregnancy by the finding of a single yolk sac

Monochorionic/Monoamniotic Twin Ectopic Pregnancy

A twin ectopic pregnancy is rare. A monochorionic, monoamniotic twin pregnancy is also rare. The authors present a case of an ectopic monochorionic, monoamniotic twin pregnancy diagnosed by the presence of a single yolk sac. The characteristics and diagnosis of monoamniotic twin pregnancies during the first trimester are discussed.

Limited Day to Day Variation of IgY Levels in Eggs from Individual Laying Hens

Laying hens are highly efficient producers of polyclonal antibodies (PAbs). These antibodies are transported to the egg yolk in large quantities from the blood of laying hens. The IgY concentration in the egg yolk is important to protect the newly hatched chick against infections and it is also an important factor for the production of yolk antibodies for commercial purposes. A single egg yolk contains approximately the same amount of IgY as 30 ml of blood. This is a significant loss of antibodies for an animal the size of a hen. We have studied the IgY levels in egg yolk. We found low day to day variability. There was no decrease in IgY levels at the end of the egg laying cycle and there was no correlation between IgY concentration and egg production.

An examination of fertility, hatchability, embryo mortality, and chick weight in double versus single-yolked broiler breeder eggs

The objective of this study was to document the fertility and embryonic mortality problems that result in the poor hatchability of double yolk (DY) versus (single yolk) SY broiler breeder eggs. Both SY (n = 64) and DY (n = 141) eggs were collected from a commercial Hubbard Hi-Y flock and the eggs incubated for 21 d. All eggs were candled and weighed at 7, 14 and 18 d, and any non-viable eggs were removed and broken open to assess fertility, and if fertile, stage of embryonic death. Any unhatched eggs remaining after 21 d of incubation were broken open so that fertility, hatchability and embryo mortality could be calculated. Because there is the potential for two chicks to hatch from a DY egg, fertility, hatchability, and embryo mortality were calculated on a per yolk basis rather than an egg basis. Fertility, hatchability, and hatchability of fertile eggs were significantly lower (P < 0.05) in DY compared to SY eggs. Early- (≤7 d of incubation), mid (8–14 d of incubation), and late (≥15 d of incubation) embryonic mortality was significantly higher in DY vs. SY eggs. Chick body weights were significantly greater in solitary chicks hatching from DY eggs versus chicks hatching from SY eggs. Key words: Double yolk, embryo mortality, broiler breeders, chick weight, hatchability, fertility

Comparison of embryos and chicks that developed as single individuals in double yolk eggs with those that developed in single yolk eggs

Body weight and muscle characteristics of 18- to 20-d-old broiler strain embryos developing in double yolk eggs (DY) that contained one embryo and one infertile ovum were compared with embryos in single yolk eggs (SY). Similar comparisons were made in the posthatching period. In some DY eggs, the embryos were bathed in a watery yolk-like fluid with no distinct second yolk present (Type 1 embryo). In others, the second yolk was contained within the vitelline membrane and surrounded by a vascularized membrane (Type 2). These embryos were heavier than Type 1 or embryos in SY eggs by 20 d of incubation. Their Pectoralis superficialis were heavier and had significantly more protein and DNA. Chicks that hatched from the DY eggs were heavier than those that hatched from SY eggs and they had heavier P. superficialis through at least 14 d of age. Pectoralis superficialis myofibers of chicks from DY eggs had greater cross-sectional area than those from SY eggs. Myofibers in the Semimembranosus of 7- and 14 d-old chicks from DY eggs tended to be larger than those from SY eggs, but the differences were not significant. There was no difference in apparent myofiber number in the Semimembranosus of the two types of chicks. The difference in BW between the two types of chicks diminished over time, so that by 42 d of age they were virtually identical. In summary, a nutritionally enriched in ovo environment resulted in embryos and chicks with enhanced growth and muscle mass, but the effects of enrichment diminished during posthatching life and eventually disappeared.

Deep-water ichthyoplankton of the Skagerrak with special reference toCoryphaenoides rupestrisGunnerus, 1765 (Pisces, Macrouridae) andArgentina silus(Ascanius, 1775) (Pisces, Argentinidae)

Abstract Two species, Coryphaenoides rupestris and Argentina silus, were abundant in the ichthyoplankton of the 150–550 m depth zone of the Skagerrak in 1992. Eggs of C. rupestris occurred only in October and December and a single yolk sac larva was caught in December. Postlarvae and juveniles occurred in all months (Feb, Apr, Jun, Oct, Dec) and showed a continuous increase in length through the year. This confirms earlier indications of a single late autumn spawning period. By October the juveniles had attained a demersal mode of life. Argentina silus eggs and larvae occurred year-round, but eggs were most abundant in the spring. Most of the other fish eggs and larvae were probably caught incidentally in surface layers. Exceptions may be four postlarval Atlantic halibut Hippoglossus hippoglossus L.