Navodon Modestus Research Articles

On the natural spawning of the file fish, Navodon modestus (GÜNTHER), in the culture pond

On the natural spawning of the file fish, Navodon modestus (GÜNTHER), in the culture pond

Filefish (Navodon modestus) culture at Kurahashi-jima, Hiroshima Pref.

Filefish (Navodon modestus) culture at Kurahashi-jima, Hiroshima Pref.

트롤 어선에서 어획후 투기된 어류의 생존율

끌그물로부터 탈출한 소형어류의 생존율을 향상시킬 수 있는 자원관리형 어구어법을 개발하기 위한 기초 조사로서, 트롤망에서 양망 후 투기되는 어류의 생존율을 조사하기 위한 시험조업이 한국 남해안 및 제주도 근해에서 이루어졌다. 트롤망의 끝자루를 탈출한 소형어류를 선내에 비치된 사육수조에 수용하여 시간대별로 생존지속 시간을 조사하였다. 그 결과를 요약하면 다음과 같다. 1. 트롤 어구로부터 어획된 어류를 선상에 비치된 사육수조에 넣어 생존율을 조사한 결과 살오징어, 한치, 갈치, 달고기, 삼치, 참조기 및 눈볼대등 대부분의 어종은 양망후 즉시 사망하였다. 2 두툽상어, 붕장, 가오리, 말쥐치, 부채새우 등은 수조내에서 장시간 생존하였으므로 이들 어종은 투기된 후에 생존할 확률이 높을 것으로 생각된다. 3. 탈출장치를 빠져나온 등가시치는 수조에 수용된지 6 시간 이내에 전부 사망하였으나,97% 의 두툽상어와 72% 의 붕장어는 72시간 이상 생존하였다. 4. 끝자루를 빠져나온 가오리는 수조에 수용된지 60시간 이내에 모두 사망하였으나, 25% 의 말쥐치와 문어는 72시간 이상 생존하였다. 5. 홍감팽의 경우 탈출장치와 끝자루를 빠져나온 개체간의 생존율을 비교해보면, 끝자루를 빠져나온 홍감팽은 72 시간 이내에 전부 사망하였으나, 탈출장치를 빠져나온 것의 8.3%는 72시간 이상 생존하는 것을 보여줌으로서, 탈출장치를 빠져나온 개체의 생존율이 다소 높은 것을 보여주었다. 6. 그러나 부채새우의 경우를 비교해 보면, 끝자루를 탈출한 새우의 생존율이 75%로서 탈출장치를 빠져나온 부채새우의 생존율 33% 보다 훨씬 높게 나타났다. 따라서, 탈출후의 어종별 생존 특성에 대해서 보다 많은 연구가 필요할 것으로 본다. Experimental fishing was carried out to investigate the survival rate of fishes discarded after hauling from the trawl and to develop the fishing gear and method for fisheries management which can improve the survival rate of young fishes escaped from the trawl codend in offshore korean southern sea and off Cheju Island of Korea. The young fishes were bred in fish cage on the board to measure the sustainable survival time for fishes escaped from grid panel and codend. The obtained results are summarized as follows' 1. Japanese flying squid(Todarodes pacjficus), mitra squid(Loligo chinesis), hair-tail( Trichiurus lepturus), john dory(Zeus japonicus), spanish mackerel(Scomberomorus niphonius), redlip croaker (Pseudosciaena polyactis) and blackthroat seaperch(Doederliinia berycoides) were dead instantly after hauling. 2. Survival rate of tiger shark(Galeocerdo cuvier), conger eel (Conger myriaster), red skate (Dasyatis akajei), black scraper(Navodon modestus) and japanese fan lobster(Ibacus ciliatus) might be high after discarding because they survived for long hours in fish cage. 3. Blotched eelpout(Zoarces gili) escaped from the escapement device(grid) was dead within 6 hours in the water tank installed on the board but 97% of tiger shark and 72% of conger eel survived over 72 hours. 4. Red skate escaped from trawl codend was dead within 60 hours in the water tank installed on the board but sustainable survival time of 25% of octopus(Paroctopus dofleini) and 100% of black scraper was over 72 hours. 5. Compared with the survival rate of rosefish(Helicolenus higendorfi) escaped from the escapement device(grid) and trawl codend, all of the rosefish escaped from the grid was dead within 7.2 hours but 8.3% of the rosefish escaped from the codend survived over 72 hours. 6. In comparison with the survival rate of japanese fan lobster survived over 72 hours, survival rate of japanese fan lobster escaped the codend was much higher as 75% than 33% of japanese fan lobster escaped from the grid.

但馬沖中層型浮魚礁周辺の昼間の魚影分布について

Three mid-layer floating reefs made of steel were deployed at a depth of 80-90m off Tajima in the Japan Sea in May 1987. To examine the distribution of fish around the reefs, an acous-tic survey over a 3×2km area, 70-110m in depth, and ROV observations were carried out during the daytime in May and August, 1988. Around the mid-layer reefs, Navodon modestus and Trachurus japonica were observed. Sol-itary Navodon modestus were close to the reef (within 10m) in the daytime, and were thought to settle on the reef at night. As Trachurus japonica, observed in August, was distributed around the floating reefs and a sunken ship in dense small schools, they were not seen else-where in the survey area. The mid-layer floating reef was concluded to act as a schooling ground for Trachurus japonica in the daytime. In May, many scattering fish echoes, which were thought to be a mixture of small squid, pelagic crustacea and others, were distributed over the whole survey area. They stayed around the reef twice-a scattering fish echo stayed at the bottom layer around the reefs for more than few hours, and a dense fish school stayed beneath the mid-layer reef for a short dura-tion. These phenomena were concluded to show an attraction and detention function of the mid-layer floating reef.

The edinger-westphal nucleus in the filefish ( Navodon modestus)

The edinger-westphal nucleus in the filefish ( Navodon modestus)

Screening of Tetrodotoxin and Its Derivatives in Puffer-related Species.

Attempts were made to detect tetrodotoxin (TTX) and its derivatives in the following fish species which are phylogenically related to the family Tetraodontidae: spiny puffer “harisenbon” Diodon holacanthus, sunfish “manbou” Mola mola, “uchiwafugu” puffer Triodon bursarius, “kawahagi” filefish Stephanolepis cirrhifer, and “umazurahagi” filefish Navodon modestus. The liver of each species did not show toxicity (<5MU/g) when assayed by the official method using mice. The liver was extracted with acidic methanol, and the TTX fraction was separated from the extract by the method consisting mainly of ultrafiltration and gel chromatography. In UV, HPLC, and GC-MS analyses, TTX fraction from spiny puffer showed anyhdroTTX, in addition to a small amount of TTX, which coincided with the phylogenically closest relationship of this species to the family Tetraodontidae.

Pretectum and accessory optic system in the filefish Navodon modestus (Balistidae, Teleostei) with special reference to visual projections to the cerebellum and oculomotor nuclei.

The fiber connections of the accessory optic system (AOS) were investigated in a balistid fish, Navodon modestus (filefish), by means of horseradish peroxidase (HRP) and degeneration methods. Following injections of HRP into the corpus cerebelli, neurons in two retinal recipient nuclei, the area pretectalis pars dorsalis (APd) and area pretectalis pars ventralis (APv), were labeled retrogradely. In addition, a few neurons near the nucleus of the accessory optic tract (nAOT) were labeled. These neurons have dendrites extending into nAOT. Neurons in APv were also labeled by HRP injections into the oculomotor complex (nIII). However, no neurons were labeled in APd or nAOT. A few neurons in the lateral part of APv were labeled by HRP injections into the abducens nucleus (nVI). Three nuclei of the AOS, APd, APv and nAOT, were shown to receive tectal projections by the Fink-Heimer method. Thus, APv receives retinal and tectal projections, and in turn projects to corpus cerebelli, nIII and nVI. Specific efferent connections of the AOS in teleosts are discussed from phylogenetic aspects.

Cytoarchitecture and fiber connections of the superficial pretectum in a teleost, Navodon modestus

Fiber connections of the so-called nucleus geniculatus lateralis (or the nucleus pretectalis superficialis pars parvocellularis) in a teleost, Navodon modestus, were examined by means of the horseradish peroxidase (HRP) tracing method. The nucleus receives fibers from the contralateral retina, ipsilateral optic tectum and nucleus isthmi, and projects bilaterally to the nucleus intermedius of Brickner and ipsilaterally to the optic tectum and raphe nuclei. The fiber connections suggest that the nucleus relays mainly visual information to the inferior lobe (hypothalamus) but not to the telencephalon. The nucleus is not a homologous structure to the lateral geniculate nucleus in other vertebrate classes.

Cytoarchitecture, synaptic organization and Fiber Connections of the nucleus olfactoretinalis in a teleost ( Navodon modestus)

Cytoarchitecture, synaptic organization and fiber connections of the nucleus olfactoretinalis (NOR) in a teleost, Navodon modestus, have been studied light- and electron-microscopically using an HRP or HRP-degeneration combined method. Following HRP injections into the optic nerve, most contralateral and a few ipsilateral neurons in the NOR were labeled. There are two types of neurons in NOR. Type I neurons have a medium-sized spindle-shaped soma with a round nucleus, and type II neurons have a large oval soma with an invaginated nucleus and contain cored vesicles (80–130 nm in diameter). Afferent terminals which form synaptic contacts with cell bodies of NOR neurons were classified into 3 types according to their morphological characteristics; S, F1 and F2 terminals. S terminals originated in ipsilateral area ventralis telencephali pars supracommissuralis (Vs). These terminals contain both spherical and cored vesicles, and make synaptic contacts with both type I and type II neurons. F1 terminals, which originated in ipsilateral area dorsalis telencephali pars posterior (Dp), are large in profile, and contain flat vesicles and mitochondria with irregularly arranged cristae. These terminals make synaptic contacts only with type I neurons. F2 terminals are small in profile, and contain flat vesicles, cored vesicles and small mitochondria with regularly arranged cristae. F2 terminals make synaptic contacts with both type I and type II neurons. The functional significance of NOR and the relationship between NOR and the ganglion of the nervus terminalis are discussed.

Fiber connections and synaptic organization of the preoptic retinopetal nucleus in the filefish (balistidae, teleostei)

Neuron cell bodies of the preoptic retinopetal nucleus (PRN), located in the diencephalon of the filefish , Navodon modestus, project axons to the retina. In the present study, the fiber connections and synaptic organization of the preoptic retinopetal nucleus (PRN) were investigated light- and electron-microscopically. The majority of neural cell bodies are located in the rostral half of this rostro-caudally elongated nucleus. Four types of synaptic terminals are distinguishable. The first (L) consists of large, irregularly shaped terminals that contain electron-dense mitochondria and numerous synaptic vesicles. These profiles make asymmetrical multi-synaptic contacts and gap junctions with somata and dendrites. The L terminals are also presynaptic to a second class of terminals (P), which have pleomorphic synaptic vesicles and form synapses onto dendrites. F terminals which have flat synaptic vesicles were also seen PRN. Very few S terminals were also seen in PRN. This type of terminal contains spherical synaptic vesicles of various sizes and a few pale mitochondria. S terminals form asymmetrical synapses with somata, dendrites and P terminals. Following unilateral tectal ablation, degenerating fibers from the lesion were traced into PRN bilaterally, although ipsilateral projections were far more numerous. L terminals exhibit degenerative changes after large tectal resection, whereas S terminals degenerate after contralateral eye enucleation. Therefore, a tecto-PRN-retinal circuit and a reciprocal connection between the retina and PRN have been documented. The similarity between PRN in the filefish and retinopetal nuclei in other classes of vertebrates, especially the isthmo-optic nucleus in birds, is discussed.

マダイ音響馴致漁場における魚群の行動について

Experimental ?? nursery of Pagrus major using acoustic conditioning had been constructed by Ohita Prefectural Fisheries Experimental Station. In a previous paper, the behavioral characters and community ecology of fishes around the feeder were reported seven months after Pagrus major had been released. After an additional twelve months, behavior of Pagrus major and some other fishes were investigated by direct observation, by some automatic recording instruments and by all the day observation using echosounder and some instrument. 1. Around the feeder, fifty-six kinds of fishes were found and two-thirds of them were the same species as previously observed. 2. Number of fishes was seen to have increased compared to the previous observation. The dominant fishes were Navodon modestus, Parapristipoma trilineatum, Pagrus major, Apogon semilineatus and Trachurus japonicus, as in the previous observation the former three kinds of fishes were the dominants. 3. Navodon modestus and Parapristipoma trilineatum were almost the same size as in the previous observation. Pagrus major had grown up from 16-17 cm to 25-30 cm in total length, but their number had decreased to about one-fourth. 4. In the daytime, Pagrus major swam at the bottom layer or rested on the bottom. When the feed was scattered by the feeder, they clustered just beneath the feeder and fed actively at the bottom layer and sometimes rose to the midwater layer. In the nighttime, they rested at the bottom.

Cytoarchitecture, fiber connections, and ultrastructure of nucleus isthmi in a teleost (Navodon modestus) with a special reference to degenerating isthmic afferents from optic tectum and nucleus pretectalis.

Cytoarchitecture and fiber connections of the nucleus isthmi in a teleost (Navodon modestus) were studied by means of Nissl, Bodian, toluidine blue, Golgi, and Fink-Heimer methods. Synaptic terminals were classified by the ultrastructural characteristics, and their origins were determined by electron microscopic degeneration experiments. The nucleus isthmi is composed of an outer cellular area or shell and an inner noncellular area or core. The shell covers anterior, dorsal, and ventral aspects of the core. The cell bodies in the shell are oval (15 x 20 micrometers) with an anteroposterior long axis, and have many somatic spines. Spines are also seen on the initial segment of the axon. Primary dendrites extend posteromedially and branch out in the core. The core contains thin and thick myelinated fibers, which originate in the optic tectum and in the nucleus pretectalis, respectively. At least two types of axon terminal were distinguished in the nucleus isthmi: S type, containing spherical vesicles, and F type, containing flattened vesicles. S terminals are derived from thin myelinated fibers and are only seen in the core where they form asymmetric synapses with dendrites. Frequently a portion of the S terminal membrane near the usual synaptic cleft is in close apposition with the membrane of an adjacent small dendrite or spine. F terminals, which derived from thick myelinated fibers, make symmetric synaptic contacts with both cell bodies in the shell and dendrites in the core. S terminals degenerate after ipsilateral ablation of the optic tectum, whereas F terminals degenerate after destruction of the nucleus pretectalis.

Status of underused fish in China

The report sums-up the present situation and tendencies in the production of foodstuffs using fish species which are underused in China. Three fish species (Navodon modestus, Lophiomus litulon and Trichiurus haumela) are now being used in the preparation of foodstuffs. Using conventional Chinese and foreign methods of food preparation various products can be prepared. After having been eviscerated, beheaded and skinned, Navodon modestus and Lophiomus litulon can be frozen, salted, dried, canned or prepared as special food portions. Fish fillets can be converted into seasoned and dried products, mince, fish substitutes, concentrated fish protein and special products such as dried fish fibres and slices fried in sauce. Fish sauce and paste can be produced from the leftovers from Navodon modestus and Lophiomus litulon, hence there is virtually no product wastage. The article describes the transformation processes for some principle products and reports on problems associated with raw material transformation and subsequent marketing.

人工魚礁近傍の魚群生態に関する基礎的研究 ＩＩＩ マダイ音響じゅん致漁場におけるマダイを中心とした数種の魚群行動について

Experimental fish nursery of Pagrus major using acoustic conditioning had been constructed by Ohita Prefectural Fisheries Experimental Station. Young of Pagrus major were conditioned to feed immediately when the sound started in the feeding net cage, then they were released in Yonozu bay. In the bay, they were fed by an automatic feeder (feeding buoy) subsequently. After seven months, the behavioral characters and community ecology of fishes around the feeder were investigated by direct observation and by some automatic recording instruments. As results, some phenomena concerning the behavior of fishes were found as follows. (1) Around the feeder, fifty-seven kinds of fishes were found and the dominans were Navodon modestus, Parapristipoma trilineatum and Pagrus major. (2) In the daytime, Navodon modestus aggregated beneath the feeder or near the aritificial reefs, and when artificial diet was scatered by the feeder, they clustered beneath the feeder and fed actively. in the nighttime, theyrested at the bottom near the artificial reefs. (3) Parapristipoma trilineatum aggregated around the rocks near the feeder in the daytime, and fed the diet in the nighttime. (4) Pagrus major (16-17cm in total length) came near the feeder only in the daytime and fed at the bottom. (5) It seemed that most of the diet scattered from the feeder was fed on by these three species of fishes, and it was calculated that Pagrus major fed on about 20 percent of all diet scattered.

Topographic projections between the nucleus isthmi and the optic tectum in a teleost, Navodon Modestus

Following horseradish peroxidase injections into the optic tectum of a teleost, Navodon modestus, reciprocal and topographic projections between the nucleus isthmi and the ipsilateral optic tectum were determined. The isthmo-tectal fibers diverge to the optic tectum while maintaining the spatial arrangements of the isthmic cells from which the fibers originate. The tecto-isthmic projections also keep the spatial arrangements in the optic tectum. The tectal fibers converge near the nucleus isthmi and terminate in the non-cellular portion of the nucleus. The reciprocal topography is apparent in the combined results of 9 experiments with one tectal injection in each region. No labeled cells and fibers were found in the contralateral nucleus isthmi.

A retinopetal nucleus in the preoptic area in a teleost, Navodon modestus

Following horseradish peroxidase (HRP) applications to the optic nerve of a teleost ( Navodon modestus), a retinopetal nucleus was identified in the contralateral preoptic area. The nucleus was composed of small (7–10 μm) round cells. Centrifugal fibers from the nucleus were traced to the inner nuclear layer of the ipsilateral retina by both orthograde HRP and Fink-Heimer methods. The cells in the nucleus showed no neurosecretion. The retinopetal nucleus or neurons could not be found in Carassius carassius. No retinopetal neurons were found in the optic tectum in both species.

Isthmic afferent neurons identified by the retrograde HRP method in a teleost, Navodon modestus

Isthmic afferent neurons were investigated by the retrograde horseradish peroxidase (HRP) method in a teleost, Navodon modestus. Following HRP injections into the nucleus isthmi, large pyriform neurons are labeled in the ipsilateral optic tectum. Very large and multipolar neurons are also labeled in the ipsilateral nucleus pretectalis. No labeled neurons were found in other areas.

Cytogenetical studies on fishes. I. Karyotypes of four filefishes.

Karyological studies in four species of filefish belonging to Balistidae (Stephanolepis cirrhifer, S. japonicus, Paramonacanthus oblongus, and Navodon modestus) were carried out. Diploid chromosome numbers in Stephanolepis cirrhifer, S. japonicus, and Paramonacanthus oblongus, were 34, but in Navodon modestus, 40. All chromosomes in these four species were acrocentrics. In three species with 2n=34, the secondary constriction was found in one chromosome pair differing from each other.

ウマヅラハギにみられた顕著な脊椎彎曲症

ウマヅラハギにみられた顕著な脊椎彎曲症