Pleurogrammus Azonus Research Articles

Spawning ground selection and larval feeding habits of Arabesque greenling Pleurogrammus azonus around the Matsumae Peninsula, Japan

Spawning ground selection and larval feeding habits of Arabesque greenling Pleurogrammus azonus around the Matsumae Peninsula, Japan

Broadband target strength of arabesque greenling, Pacific sand lance, and pointhead flounder

Abstract Measurement of target strength (TS) is important for estimating the abundance of species using fisheries acoustics. However, most researchers have only used a limited number of representative frequencies for acoustic measurements of fish without a swim bladder (bladderless fish). Here, we measured the broadband TS of three bladderless fish species, arabesque greenling (Pleurogrammus azonus), Pacific sand lance (Ammodytes personatus), and pointhead flounder (Cleisthenes pinetorum), using two broadband echosounders. TS measurements were conducted in a seawater tank over frequency ranges of 45–90 and 80–120 kHz using a tether method. Higher TS and directivity were observed at higher frequencies than at lower frequencies for pointhead flounder and arabesque greenling. However, the TS for Pacific sand lance was relatively flat over the measured frequency spectra. Additionally, the TS of pointhead flounder and Pacific sand lance could be expressed as a function of body length and the TS of arabesque greenling could be expressed as a function of body length and frequency, which could be used in fish species discriminations and size estimations.

The interaction of endogenous and exogenous factors in the biological rhythms of the Arabesque greenling Pleurogrammus azonus in the Primorie waters

Arabesque greenling Pleurogrammus azonus is an important commercial species in the waters of Russia and Japan. In the Russian waters of the Japan Sea, regular study of its biology was conducted in the waters of the Primorsky Krai, where annual trawl surveys were performed. Material collections covered the entire calendar year. Endogenous rhythms (internal biological clocks) play a crucial role in the coordination of biorhythms of the Arabesque greenling Pleurogrammus azonus. This assumption is confirmed by the different duration of exogenous and endogenous rhythms: the dynamics of the temperature index has a pronounced periodization equal to one astronomical year, and the duration of the mixed rhythms in the dynamics of physiological processes and main components changes with age. The relationship of somatic and generative growth with temperature oscillation is subjected to age-related variability. In juveniles, this relationship is not clearly traceable. At the beginning of puberty period, significant connections are manifested. Then the dependence of growth indicators on the temperature oscillation is reduced, as the selective ability of the Arabesque greenling to choose the temperature range increases. Selective ability to environmental conditions is largely determined not by individual but by group behavior.

Dynamics of the size and age composition of the arabesque greenling Pleurogrammus azonus in the pelagial of the russian waters in the sea of Japan

In the pelagial of the Russian waters of the Sea of Japan, juveniles and adults of the Arabesque greenling Pleurogrammus azonus are found from March to November. The average size of fingerlings of Arabesque greenling increase from South to North. Larger sizes of fingerlings in the north are determined by earlier spawning, compared to the south. Density aggregations of Arabesque greenling in the pelagic zone is much smaller than in the bottom layers of water. High migration activity is characteristic of a smaller hart of individuals.

Prespawning and Spawning Migrations of the Southern Greenling Pleurogrammus azonus (Mathematical Model)

Prespawning and spawning migrations of the southern one-finned greenling Pleurogrammus azonus in the bay are considered on the basis of the author's and literary numerical material. Peter the Great, in the summer-autumn period. As part of the spatiotemporal model building, the pre-spawning and spawning migrations were formalized. The dynamics of diurnal displacements is made in terms of transport equations. The recording of their representations follows the modified Patlack-Keller-Segel equations, according to which the flow of objects/substance is directed along the gradients of the stimulus zone functions introduced here. It is believed that in the pre-spawning period, morphophysiological and behavioral adaptations to a rather long and energyconsuming spawning occur. It is shown that the intensity of daily movements is proportional to their linear size (the larger the fish, the faster it moves). The equations for the spawning stage take into account the spatial competition of males, which under natural conditions is observed only in the vicinity of spawning areas. For females, clusters of males act as an incentive for movement. The simulation results turn out to be close to the observed migration regime.

Long-term mean biomass and dominant fish species in the bottom and near-bottom biotopes of Peter the Great Bay

Biomass and species composition of demersal fish in the bottom biotopes of Peter the Great Bay (Japan Sea) are considered on the data of 2428 trawl catches in 36 surveys conducted by Pacific Res. Inst. of Fisheries and Oceanography (TINRO) in 1978–2009. The most common 20 species are ranked, as the basis of ichthyocenoses, by areas of the bay. The long-term mean total biomass of fish in the bay is estimated as 75,500 t. Arabesque greenling Pleurogrammus azonus, japanese flounder Pseudopleuronectes yokohamae and saffron cod Eleginus gracilis are distinguished by the highest mean biomass. Mean density of fish distribution varied from 6.2 to 19.4 t/km2. It was the highest in the middle Ussuri Bay (13.95 t/km2; mean fish biomass in the area 18,230 t) and in the estuarine areas. Besides, the data on long-term mean biomass of benthos collected in the same trawl surveys and zooplankton sampled in 117 plankton surveys in 1988–2013 are presented.

Target-based catch-per-unit-effort standardization in multispecies fisheries

Standardized catch per unit effort (CPUE) is a fundamental component of fishery stock assessment. In multispecies fisheries, catchability can differ depending on which species is being targeted, and so the yearly trend extracted from the standardized CPUE is likely to be biased. We have, therefore, developed a method for predicting the unobserved variable related to targeted species from among multispecies composition data using a mixture regression model for the transformed residuals. In contrast with traditional methods, the proposed method predicts the target variable in CPUE standardization without removing a subset of the data. Keeping the entire data set avoids information loss, and so CPUE standardization with the predicted target variable should yield an unbiased estimate of the yearly trend. Simple simulation tests demonstrate that our method outperforms traditional methods. We illustrate the use of our method by applying it to CPUE data on arabesque greenling (Pleurogrammus azonus) caught in multispecies trawl fisheries in Hokkaido, Japan.

Age and growth of the Okhotsk atka mackerel, Pleurogrammus azonus in the coastal of Gangwon-do, East Sea

Age and growth of the Okhotsk atka mackerel, Pleurogrammus azonus in the coastal of Gangwon-do, East Sea

Diets of Steller sea lions off the coast of Hokkaido, Japan: An inter‐decadal and geographic comparison

AbstractInter‐decadal and geographic variations in the diets of Steller sea lion, Eumetopias jubatus, were examined based on the contents of 408 stomachs collected from coastal areas around Hokkaido Island during the periods 1994–1998 and 2005–2012. The most important prey species in the 1990s were gadid fishes (walleye pollock [Gadus chalcogrammus], Pacific cod [Gadus microcephalus] and saffron cod [Eleginus gracilis]). The frequency of occurrence and gravimetric contribution of gadids decreased in the 2000s latter period at three study sites (Rausu, Shakotan and Rebun) and were replaced by Okhotsk Atka mackerel (Pleurogrammus azonus) and smooth lumpsucker (Aptocyclus ventricosus). However, analysis based on gravimetric composition indicated that the dietary diversity of prey showed only a slight inter‐decadal difference, reflecting the wide diversity of prey ingested during both study periods. These results indicate that Steller sea lions along the Hokkaido coast are opportunistic feeders that utilize a wide variety of prey, and appear to feed mainly upon prey that is easily obtained.

Relationship between temperature and embryonic period of Arabesque greenling Pleurogrammus azonus

Relationship between temperature and embryonic period of Arabesque greenling Pleurogrammus azonus

Species composition and biomass of fishes by the data of bottom trawls in the northwestern Japan Sea in 1978-1990

State of the demersal fish community in the northwestern Japan Sea in the period 1978-1990 is considered on the data of bottom trawl surveys. Mean total biomass of the demersal fish in the USSR economic zone in those times is estimated as 1.106 . 10 6 t. The bulk of fish community was formed by the families Gadidae, Pleuronectidae, Clupeidae, Hexagrammidae, and Cottidae with summary portion 95.1 % by biomass and 84.8 % by number. The most abundant fish species were walleye pollock Theragra chalcogramma (44.8 % of the biomass), scale-eye plaice Acanthopsetta nadeshnyi (12.2 %), pacific herring Clupea pallasii (8.6 %), blackfin flounder Glyptocephalus stelleri (7.7 %), pacific cod Gadus macrocephalus (4.7 %), and arabesque greenling Pleurogrammus azonus (4.6 %), portions of other species didn’t exceed 3 %. The summary portion of flounders (23 species) was 28.0 %, by biomass. Scale-eye plaice dominated among them (on average 135.4 . 10 3 t), other mass flounders were the blackfin flounder (84.8 . 10 3 t), yellowstriped flounder Pseudopleuronectes herzensteini (29.0 . 10 3 t), and yellowfin sole Limanda aspera (13.2 . 10 3 t) though the latter species had dominated there in the 1930s.

Otolith microstructure of Arabesque greenling Pleurogrammus azonus: A species with a long embryonic period

We investigated the relationship between morphological development in the embryonic stage and the formation of otolith microstructure in Arabesque greenling Pleurogrammus azonus, and then validated that the otolith increments were formed on a daily basis. Increments were more consistent to count and measure in sagittal otoliths from wild caught larvae compared to lapillar otoliths, and we suggest that sagittal otoliths as suitable for otolith microstructure analysis. This study clarified the formation time of three prominent increments on the sagittal otolith. First prominent increment (approx. 17mm in otolith radius (OR)) was coincident with the time of eye-pigmentation in the embryonic stage. Second (approx. 36μm OR) was considered to be the hatch increment and the third (approx. 38μm OR) was at the time of transition from endogenous to exogenous nutrition. The third prominent increment which was the clearest radius (termed below as the check) was used as the starting point for validating the daily increment formation in sagittal otolith, and also there was no significant difference in the check radius among reared (6, 8, and 10°C) and wild caught larvae. The relationship between number of days after hatching and the number of increments formed after check was significant and the slope of the regression line was not different from 1, validating the assumption that growth increments are formed on a daily basis in sagittae of P. azonus. The check was formed on the otolith at the transition from endogenous to exogenous nutrition, and the number of days required prior to its formation varied with water temperature. For the species in which the check is formed at the nutritional transition from endogenous to exogenous feeding, the relationship between number of days to check formation and water temperature is essential to estimate the hatch date of wild caught individuals.

道西日本海におけるホッケ<i>Pleurogrammus azonus</i>雌の成熟過程と成熟特性

道西日本海におけるホッケ<i>Pleurogrammus azonus</i>雌の成熟過程と成熟特性

State of the stock and features of the fishery for arabesque greenling <i>Pleurogrammus azonus</i> Jordan at Metz (1913) in the waters of southern Kuril Islands

State of the stock and features of the fishery for arabesque greenling <i>Pleurogrammus azonus</i> Jordan at Metz (1913) in the waters of southern Kuril Islands

Morphological and molecular genetic characterization of two Kudoa spp., K. musculoliquefaciens, and K. pleurogrammi n. sp. (Myxosporea: Multivalvulida), causing myoliquefaction of commercial marine fish.

Genetic characterization of myxosporean species, including members of the genus Kudoa, has advanced dramatically throughout the last decade. This is in stark contrast to those species described further back in time. Kudoa musculoliquefaciens described from the jellied muscle of swordfish, Xiphias gladius, in the western Pacific Ocean off the Sanriku Coast, northern Japan, is one such species. In the present study, multiple pseudocysts (0.66-1.35mm average length and 0.06-0.10mm average width) containing K. musculoliquefaciens spores were collected from three host groups: muscle blocks of swordfish caught in the western Pacific Ocean off the Sanriku Coast, or the northern Indian Ocean, and Indo-Pacific sailfish, Istiophorus platypterus, in the western Pacific Ocean off Kochi, western Japan. Subspherical K. musculoliquefaciens spores, 8.0-10.3μm in width, 7.3-10.0μm in thickness, 6.4-7.9μm in sutural thickness, and 5.5-8.1μm in length, had four subspherical polar capsules, 2.8-4.0μm in length by 2.2-3.2μm in width. The kudoid spores found in the different host groups showed morphometric variations to some extent but had essentially identical nucleotide sequences of the ribosomal RNA gene (rDNA), closest to those of Kudoa hemiscylli or Kudoa carcharhini recorded from elasmobranchs in the Indo-Pacific Ocean. Another kudoid species, Kudoa pleurogrammi n. sp., was recorded from the jellied and normal muscles of Atka mackerel, Pleurogrammus monopterygius and Pleurogrammus azonus, fished in the northern Pacific Ocean or northern Sea of Japan. Subquadrate spores found in round-ended pseudocysts (1.15-3.85mm in length and 0.11-0.26mm in width) in myofibers were 8.2-9.1μm in width, 7.1-8.2μm in thickness, 5.4-7.7μm in sutural thickness, and 5.6-6.8μm in length, with four ovoid polar capsules, 2.7-2.9μm in length by 1.4-2.0μm in width. Kudoid spores from both jellied and normal muscles or different host fish species had identical 18S or 28S rDNA nucleotide sequences. Thus, molecular genetic characterization of kudoid species with the potential to induce post-mortem myoliquefaction will facilitate the reliable and specific identification of myxosporeans found in either jellied or normal muscles of important commercial fish.

Spatial association between northern fur seal (Callorhinus ursinus) and potential prey distribution during the wintering period in the northern Sea of Japan

AbstractElucidating the response of marine predators to oceanographic features helps in understanding their foraging strategies and the cause of their spatial overlap and interference with fishery activities. Northern fur seal is a highly pelagic species during the wintering period. In recent years, fur seals have consistently been found distributed near the coast of southwest Hokkaido, Japan. Because interference by fur seals with coastal fishery activities has become a serious concern, an understanding is sought as to why fur seals come ashore in this area. We conducted ship‐based observations and estimated fur seal density. To elucidate the spatial and seasonal association of fur seal distribution and ocean environments, we constructed statistical models to describe how potential prey distribution and oceanographic features influenced the fur seal spatial distribution during the wintering period. Fur seal distribution corresponded markedly to potential prey distribution, and they tended to aggregate along the narrow continental shelf that is the main geographic feature of this area, which is 2000 m deep and approximately 10 km from the coast. Walleye pollock [Gadus chαlcogrαmmα(Theragra chαlcogrαmmα)] and arabesque greenling (Pleurogrammus azonus), which are one of the main prey for fur seals, move to the shallow area to spawn on the continental shelf seasonally, so potential prey abundance could be higher in coastal areas than offshore. Moreover, the absence of a mesopelagic biotic community may be one of the main factors in the coastal distribution of the fur seal.

Maturation process and reproductive biology of female Arabesque greenling Pleurogrammus azonus in the Sea of Japan, off the west coast of Hokkaido

The sexual maturation process and reproductive biology of female Arabesque greenling Pleurogrammusazonus in the Sea of Japan, off the west coast of Hokkaido, was examined using histological observations of ovaries. Maturation of P. azonus was classified into seven phases based on the presence of nine oocyte stages, post ovulatory follicles, and residual unspawned ova. Although vitellogenesis of P. azonus begins annually in August, hydrated oocytes were present in September and likely occurred several times during the spawning season until November. However, few oocytes at the intermediate stages of development were found during the premature and spawning phases. Based on these observations, the maturation pattern of female P. azonus can be classified as “group-synchronous, spawning several batches in a single spawning season,” as in other hexagrammid fish. The probability of maturation of female P. azonus depended on body size rather than age. The estimated length at 50 % maturity was approximately 240 mm in standard length (SL). The mean SL of age-1 females just before the spawning season varied yearly around the 50 % maturity length. Overall, these findings suggest that the growth of female P. azonus before the spawning season at age 1 year can markedly affect spawning biomass.

Antifreeze Activity in Temperate Fish from the East Sea, Korea

Antifreeze proteins and glycoproteins [AF(G)Ps] constitute a group of proteins that lower the freezing but not the melting points of aqueous solutions, enabling polar and north-temperate fish to survive in ice-laden environments. However, little is known about antifreeze activity in temperate fish; such work would extend our knowledge on the functions and evolution of AF(G)Ps. In the present study, we screened for antifreeze activity in temperate fish caught off the coast of Jumunjin (<TEX>$37.89^{\circ}N$</TEX>), Gangneung, Korea. Thermal hysteresis (TH) and the ability to inhibit ice recrystallization (IR) in blood, liver, and muscle samples from nine fish were examined to assess antifreeze activity. As the East Sea off the coast of Jumunjin is ice-free year round, we thought it most unlikely that the fish would express antifreeze proteins. Surprisingly, the blood of Pleurogrammus azonus and three types of tissue from Gymnocanthus herzensteini, Zoarces gilli and Kareius bicoloratus exhibited measurable TH values together with the ability to trigger characteristic morphological changes in ice crystals. Blood samples from the three species also evidenced ice recrystallization (IR) inhibition. This implies that AF(G)Ps or other antifreeze-like substances are present in temperate fish even under nonfreezing conditions. These results contribute to our understanding of the functions and origins of antifreeze activity in fish.

Differential effects of the environment on the growth of arabesque greenling (Pleurogrammus azonus): does rising temperature benefit young but not old fish?

Annual and spatial variations in the growth condition of the arabesque greenling (Pleurogrammus azonus) were examined in relation to temperature and food availability. We found age-dependent effects of temperature and sex-dependent effects of zooplankton biomass on the growth condition. Growth condition increased with bottom temperature in the 1+ group, but this effect was reversed in the older groups. This age-dependent effect of temperature on growth condition was consistent with regional differences in growth patterns. Arabesque greenling living in cool sea areas reached a larger final adult size (i.e. larger L ∞), but the juveniles grew slower (i.e. smaller k) than those living in warm sea areas. Based on our results, we suggest that the negative effect of climate warming on growth condition might be more severe for older individuals and that a climate change-driven decrease in the somatic growth of adult fish could bring a population growth rate decline through maternal effects.

Correlation between fat content and features of generative growth of arabesque greenling Pleurogrammus azonus

Objective: To determine the correlation between fat content and features of generative growth of arabesque greenling Pleurogrammus azonus. Methods: The samples were collected by bottom trawl during trawl surveys of research vessel MRS-055 conducted by TINRO-Center in Peter the Great Bay (Sea of Japan). A total of 332 individuals of arabesque greenling were analyzed. Fat content was determined by the standard method of extraction by sulfuric ether from the dry rest. Results: The most part of deposit fat of arabesque greenling is concentrated in muscles and hypodermis: 86.2%-97.0% (mean value 92.3%) of the total deposited fat mass. The liver fat was 1.1%-7.7% (mean value 4.8%) and the internal fat was 0.9%-5.2% (mean value 2.8%) of the total mass. Decreasing of the muscles fat was observed at sudden changes of qualitative and quantitative characteristics of sexual products, and for immature fish the relation between accumulation of fat in muscles and generative growth was not found. Conclusions: Dynamics of fat in liver corresponds closely with the processes of generative growth, and increasing of gonads weight causes decreasing of liver fat content, both for mature and immature fish.