Trachurus Japonicus Research Articles

The catch composition of light falling-net fishing and its impact on fishery resources in the northern South China Sea.

In recent years,a light falling-net fishery was rapidly developped in the South China Sea.It has increased fishing pressure on juvenile fish resources living in the northern shallow waters of South China Sea. A survey of the catch composition of light falling-net fishing was conducted on fishing ground along waters off Yangjiang,Guangdong Province,from April 27 to May 2,2006,in order to identify catch composition of the net and its impact on fishery resources. The results showed that: (1) The main species caught were phototactic fish and cephalopod,including Loligo sp.,Trichiurus haumela,Decapterus maruadsi,Scomberomorus commerson,Psenopsis anomala,Sepia sp.,Thrissa kammalensis,Formio niger,Thryssa dussumieri and Trachurus japonicus;(2) The net had high catch rates of juveniles and might tend to damage marine fishery resources;(3) The main causes resulting in the high rates were smaller mesh size,greater light intensity and fishing ground closing to inshore. It is recommended that the regulation of the minimum mesh size be implemented and the management of the fishing gear be strengthened.

Distribution and migration of age‐0 jack mackerel (Trachurus japonicus) in the East China and Yellow Seas, based on seasonal bottom trawl surveys

AbstractWe examined the distribution and migration of age‐0 jack mackerel in the East China Sea (ECS) and Yellow Sea, based on data from seasonal bottom trawl surveys. Sampling was conducted at 79–161 stations during five cruises in spring (April–June), early summer (May–July), late summer (August–October), autumn (October–December), and winter (January–February). During early summer, jack mackerel (mean 92 mm fork length), which were estimated to have hatched in the southern East China Sea (SECS) during winter, began to occur abundantly, especially along the shelf‐break region of the central East China Sea (CECS). In late summer, the distribution center of young fish (mean 126 mm) shifted northward into the shelf region of northern East China Sea (NECS), corresponding with the rise of bottom water temperature and high prey abundance. In winter when the bottom water temperature declined in the shelf region, the distribution center of jack mackerel (mean 144 mm) shifted southward, with high densities occurring in the SECS and CECS. In spring, overwintering jack mackerel that had become age‐1 (mean 175 mm) were distributed abundantly along the shelf‐break region of the ECS. On the other hand, jack mackerel were only sporadically found, generally at low densities, in the Yellow Sea during all seasons. High densities of jack mackerel were largely restricted to areas of >15°C bottom water temperature during all seasons. Our results indicate that the seasonal shifts of the 15°C isotherm of the bottom layer and the food conditions are significant environmental factors determining the migration of jack mackerel within the ECS.

A spatial analysis of trophic composition: a case study of hairtail (Trichiurus japonicus) in the East China Sea

The spatial distribution of fish on feeding grounds is an important factor in determining their prey composition. Of the factors that may influence the spatial distribution on the feeding ground and subsequent diet composition is the fish maturation stage. Using hairtail (Trichiurus japonicus) as an example, we evaluated the impacts of gonad development stage on diet composition. Hairtail supports one of the most valuable and largest fisheries in the East China Sea. As one of the top predators, it plays an important role in the ecosystem. We analyzed hairtail stomach samples collected on their feeding grounds from a fisheries-independent survey program in September 2005. Our analyses suggest that females in their third maturity stage tended to feed more intensively. Fish were the most important preys for hairtail, accounting for 72.6% of the total stomach contents in weight. The four most important fish species were juvenile hairtail (25.2%), Japanese scad (11.4%), Japanese jack mackerel (7.7%), and small yellow croaker (5.9%), suggesting strong cannibalism. A cluster analysis suggests that hairtail could be divided into three groups in their spatial distribution based on their diets: one group with similar percentages of fish and crustacean preys mainly distributed in the south of East China Sea far from the coast; one group mainly consuming fish and distributed over the north of East China Sea near the coast; and the third group consuming mainly crustacean species mainly distributed in the open sea. We hypothesize that gonadal development stage of hairtail may determine their movement from spawning ground to feeding ground, and subsequently spatial distribution on the feeding ground, which in turn results in different feeding intensities and prey compositions.

Seasonal differences in the vertical distribution pattern of Japanese jack mackerel, Trachurus japonicus: changes according to age?

Abstract Nakamura, T., and Hamano, A. 2009. Seasonal differences in the vertical distribution pattern of Japanese jack mackerel, Trachurus japonicus: changes according to age? – ICES Journal of Marine Science, 66: 1289–1295. The Japanese jack mackerel, Trachurus japonicus, is commercially and ecologically one of the most important fishery resources in Japanese waters. A clear understanding of the age-dependent, vertical distribution pattern is important for the effective and sustainable management of this resource. In this study, acoustic surveys were conducted from June to November 2001 in the western Sea of Japan to clarify seasonal differences. The survey area included a number of artificial reefs at depths >100 m. To identify fish species and determine the characteristics of the water column, simultaneous biological sampling and oceanographic surveys were carried out. The vertical distribution of Japanese jack mackerel varied with their age and size and between seasons. In June and July, aggregations of juvenile (age 0; <10 cm in length) Japanese jack mackerel were found in a layer between 20 and 50 m deep associated with a temperature range of 19–21°C. However, the age-0 aggregations were not observed from August to November. Conversely, the age-1+ schools aggregated around the artificial reefs when the temperature was <19°C. It is suggested that there are seasonal differences in the vertical distribution pattern between the early life and adult stages of Japanese jack mackerel. Because of the different vertical distributions of these life stages, acoustic backscatter information is useful for determining the age of the observed fish.

Ontogenetic and diel variation in the vertical distribution of larvae of jack mackerel Trachurus japonicus in the East China sea

Larvae of jack mackerel Trachurus japonicus were sampled in seven depth layers (0–10 m, 10–20 m, 20–30 m, 30–40 m, 40–50 m, 50–70 m, and 70–100 m), with a closing-type frame net, on 26th–27th February, 2003, at Sta. V (27°50′N, 126°00′E) continental shelf edge in the southern part of East China Sea, to examine their vertical distribution. Most of the larvae (>90%) occurred in the upper 50 m layer during both day and night. In the daytime, larvae of length from 3.0 mm to 4.5 mm were most abundant in the 10–20 m layer, those from 5.0 to 6.0 mm were most abundant in the 20–30 m layer, those from 6.0 to 8.0 mm occurred at greater depth, in the 30–40 m layer, and those more than 9.0 mm were found in the 0–10 m layer and performed ontogenetic vertical migrations. Larvae from 6 mm to 8 mm length performed diurnal vertical migration, for the percentage (16.7%) of larval number in the 0–20 m layer in the daytime increased to 42.1% at night and the percentage (78.1%) in the 20–50 m layer in the daytime decreased to 49.0% at night.

Dehydration process of fish analyzed by neutron beam imaging

Since regulation of water content of the dried fish is an important factor for the quality of the fish, water-losing process during drying (squid and Japanese horse mackerel) was analyzed through neutron beam imaging. The neutron image showed that around the shoulder of mackerel, there was a part where water content was liable to maintain high during drying. To analyze water-losing process more in detail, spatial image was produced. From the images, it was clearly indicated that the decrease of water content was regulated around the shoulder part. It was suggested that to prevent deterioration around the shoulder part of the dried fish is an important factor to keep quality of the dried fish in the storage.

Distribution and abundance of copepod nauplii in southern part of the East China Sea: implications for prey availability to jack mackerelTrachurus japonicuslarvae

In the southern part of the East China Sea (ECS), a large spawning ground of jack mackerel Trachurus japonicus has recently been found: Larval survival during the period of transport from the spawning ground along the shelf break is potentially a critical stage prior to recruitment. As such, the distribution of copepod nauplii in this region was investigated during the main spawning period in 2003–2006. The average naupliar density in 2003 was significantly higher than the other years along the shelf break, which is a major transport pathway for jack mackerel larvae (sea-surface temperature 20–23°C). Estimated egg production rates for Paracalanus spp., one of the most dominant genera of copepods in the southern ECS, based on temperature and chlorophyll-a concentration could not fully explain the spatial and annual variation in naupliar distribution and abundance. Although naupliar densities showed significant positive correlations with chlorophyll-a concentration for all years, an analysis of covariance revealed that naupliar density in 2003 was high even if the effect of chlorophyll-a concentration was excluded. This suggests that apart from copepod production, adult female distribution plays an important role in variability of the naupliar distribution and abundance in the southern ECS.

Sound generated by a payao and comparison with auditory sensitivity of jack mackerelTrachurus japonicus

Sound generated by a payao, an anchored bamboo fish aggregating device, is believed to be attractive to fish; but until now, there is no available record of payao-generated sound. This study presents payao-generated sound recorded by a hydrophone at water depths of 5, 10 and 15 m from a fixed distance of 3 m relative to the payao, and compares the sound with the auditory sensitivity of jack mackerel Trachurus japonicus measured at discrete frequencies from 100 to 2000 Hz using the auditory brainstem response protocol. A consistent peak appeared in the sound spectrum at 49 Hz and showed an increasing sound pressure level with depth, which suggests that payao sound may come from the anchor rope. However, the contribution of the bamboo raft can not yet be discounted. The hearing threshold curve indicated that the most sensitive frequency range in jack mackerel is from 92.1 dB at 800 Hz to 111.0 dB at 200 Hz. These results show that the dominant frequency range of payao sound does not correspond with the high sensitivity frequency range of fish hearing.

Genetic identification of fish eggs collected in Sendai Bay and off Johban, Japan

Mitochondrial DNA typing of 52 fish eggs collected in Sendai Bay and off Johban revealed ten haplotypes of the 225–251 bp region of 16S ribosomal DNA. Comparing with known sequences of fishes, we identified them as Trachurus japonicus (Carangidae), Pagrus major, Evynnis japonica (Sparidae), Paralichthys olivaceus, Pseudorhombus sp. (Paralichthidae), Pennahia argentata (Sciaenidae) and Platycephalus sp. (Platycephalidae). The occurrence of Trachurus japonicus and sparid eggs in the study area indicates significant extensions to the ranges of their spawning sites northward. Our method is useful for identifying fish eggs that are difficult to diagnose by morphology, and to uncover cryptic fish egg assemblages in the field.

Ontogenetic changes in the ecological function of the association behavior between jack mackerel Trachurus japonicus and jellyfish

Commensal behavior of jack mackerel Trachurus japonicus (Temminck & Schlegel) with jellyfishes has been widely observed but its ecological function is still unclear. The goal of the present research is to examine the function of association behavior with jellyfish in the laboratory and in field observations with an emphasis on ontogenetic changes. In the laboratory, jack mackerel juveniles (mean standard length (SL) = 11, 19, 38, and 55 mm) were placed in 500-l polycarbonate tanks with two live moon jellyfish, Aurelia aurita (Linne), and one artificial jellyfish made of silicon. Association behavior with either live or artificial jellyfish was visually observed under the following conditions: control, presence of a predator model, before and after feeding live Artemia, 1 h and 3 h after feeding, and at night. Jack mackerel at 11 mm SL associated with both the moon jellyfish and artificial jellyfish, unrelated to the presence of a predator model or feeding. Juveniles at 19 mm associated with moon jellyfish only in the presence of a predator model. Larger juveniles associated with moon jellyfish at 1 h and 3 h after feeding. Thus the ecological function of association was proposed to develop first from school formation, next as a hiding place from predators, and then as a food source. Underwater observations of jack mackerel associating with giant jellyfish Nemopilema nomurai (Kishinouye) in two different areas in the Sea of Japan supported this hypothesis. High predation pressure from benthic piscivorous fishes in the southern area (Tsushima) may encourage association with jellyfish, whereas pressure from pelagic predators in the northern area (Maizuru) may encourage settlement to rocky reef habitats in temperate waters. Thus the jellyfish may also function as a vehicle for the northward migration of this species.

Redescription of three species of Hysterothylacium (Nematoda: Anisakidae) from marine fishes from the Yellow Sea, China, with the synonymy of Hysterothylacium muraenesoxin (Luo, 1999)

Three species of Hysterothylacium Ward & Magath, 1917 from the Yellow Sea, China, are redescribed and illustrated by light and scanning electron microscopy. Hysterothylacium fabri (Rudolphi, 1819) collected from Chelidonichthys kumu (Cuvier), Trachurus japonicus (Temminck & Schlegel), Argyrosomus argentatus (Houttuyn), Astroconger myriaster (Brevoort) and Hysterothylacium tasmaniense (Johnston & Mawson, 1945) collected from Lophius litulon (Jordan) are reported for the first time in China. Hysterothylacium amoyense (Hsü, 1933) (originally registered as Contracaecum amoyensis from Amoy, Taiwan Strait, China) is redescribed and compared with Hysterothylacium muraenesoxin (Luo, 1999), concluding that the second species represents a junior synonymy of H. amoyense.

망지를 이용한 트롤 탈출장치 개발

Sea experiment for this study was carried out to develop a Trawl Escapement Net(TEN) using net material to improve the survival rate of undersized fishes that escaped from trawls in the Korean southern sea in May and November, 2005. Three kinds of Trawl Escapement Net(TEN) were examined to increase the escapement rate for fishes escaped from the TEN, and total catches in the codend and cover-net were investigated. The main catch species in the experimental fishing trials using a V shape TEN(A type) in May were Korean pomfret(Pampus echinogaster), slimy(Leiognathus nuchalis), gizzard shad(Konosirus punctatus), white croaker(Pennahia argentata) and smelt(Sillago sihama). In the experimental fishing trials using a V shape TEN with a protector for undersized fishes(B type) and a panel shape TEN with a protector(C type) in November, the main catch species were horse mackerel(Trachurus japonicus), sea pike (Sphyraena japonica), large-head hairtail(Trichiurus lepturus), kammal thryssa(Thryssa kammalensis), white croaker(Pennahia argentata), butterfish(Psenopsis anomala) and red gurnard(Lepidotrigla microptera). Most of large-sized fish species like Korean pomfret and Spanish mackerel could not escape through the TEN in the B type and C type. Catches of horse mackerel were highest in the experimental fishing of November and escapement rates for most fish species including horse mackerel were higher in the C type compared with B type.

Spawning ground and larval transport processes of jack mackerel Trachurus japonicus in the shelf-break region of the southern East China Sea

Horizontal distribution patterns of jack mackerel Trachurus japonicus larvae were investigated extensively in the East China Sea (ECS) along the shelf-break region between 26° and 30°N during February–March based on fine-scale larval sampling in 2002 and 2003. A total of 2363 T. japonicus ranging from 1.2 to 12.4 mm body length (BL) were collected at 310 bongo net sampling stations, of which larvae <10 mm BL accounted for 99.1%. In both years, newly hatched larvae (<3 mm BL) were concentrated in the shelf-break region mainly in the southern part of ECS between 26° and 27°N in warm water of 21–23 °C, suggesting that their primary spawning ground existed in and around this area. With growth, larvae were transported in two different directions, i.e., northward and northeastward, corresponding closely with the direction of the Kuroshio Branch Current north of Taiwan (KBCNT) and the Kuroshio, respectively. Replicate sampling cruises at 2 week intervals were conducted in 2003, and the larval distribution pattern changed significantly between the sampling cruises, suggesting that the transport process fluctuates over relatively short periods in relation to oceanographic processes. The transport speed by the KBCNT was estimated to be 0.13–0.28 knots based on the larval distribution, which is one order of magnitude slower than that by the Kuroshio (1.5–3 knots). Habitat temperature gradually declined with growth in both the Kuroshio and KBCNT, but in the KBCNT it was 1–2 °C lower than in the Kuroshio. Our results suggest that the two different larval transport processes lead to a significant difference in the transport route, habitat conditions (such as temperature and food), and site where young fish recruit to the demersal habitat, which will result in different survival and recruitment processes.

Multiple cohorts of juvenile jack mackerel Trachurus japonicus in waters along the Tsushima Warm Current

The jack mackerel, Trachurus japonicus, has a prolonged spawning season and widely spread spawning grounds. The population in the coastal waters of Japan seems to be composed of several cohorts spawned seasonally from different waters. To understand its population structure along the Tsushima Warm Current, we analysed hatchdates and growth histories of fish from Kunda Bay, the southern, central and northern East China Sea (ECS), the southern Sea of Japan, and Maizuru Bay. Seven cohorts were detected from fish collected between June 2005 and June 2006 in Kunda Bay. Comparing hatchdate distributions and growth trajectories of the seven cohorts with those of the other five regional samples, we did not find that cohorts collected in Kunda Bay originated in the southern ECS. Therefore, these coastal waters of Japan appear to be significant spawning grounds for juvenile jack mackerel.

일본 Shikoku, Ikata지역 인공어초 주변의 해양생물 군집

This study monitored a variety of marine communities during monthly or bimonthly censuses from February 1999 to August 2000. The communities investigated included artificial reefs composed of various substrates, which were placed on an area of sandy bottom at 8, 10, and 13m depths in Muronohana, Ikata, Shikoku, Japan. Economically important shell fishes, such as the turban shell and abalone, appeared on the artificial reefs after 1 month of construction. Shell fishes were recorded at levels of five to 20 individuals per reef. A total of 37 species (4 orders, 19 families) were identified during the experimental period. Apagon semilineatus, Trachurus japonicus, Pteragogus sp., and Pterogobius elapoides accumulated over an average of 100 individuals during the study period. Apagon semilineatus, Pteragogus sp., and P. elapoides accumulated over 1,000 individuals on all artificial reefs in May 1999. Trachurus japonicus reached well over 500 individuals in the artificial iron reef during June and July 2000. Higher monthly variation in fish abundance occurred during periods of high temperature, as compared to periods of low temperature between December 1999 and March 2000. More fish were observed in the artificial iron reef than in the artificial concrete reef, because the former offered a broader inner space and the shadows of the roofs served as a shelter for fish.

Jack mackerel Trachurus japonicus juveniles use jellyfish for predator avoidance and as a prey collector

Juveniles of carangid fishes including jack mackerel Trachurus japonicus are known to associate with jellyfishes. The function of this association behavior was studied through rearing experiments and underwater visual observations. Association behavior of jack mackerel with moon jellyfish in experimental tanks was more frequent in the presence compared to the absence of predators (chub mackerel Scomber japonicus). In the experimental tanks, the presence of jellyfish, however, did not mitigate predation by these predators. Although jack mackerel did not feed on the jellyfish itself, they frequently fed on the captured prey (Artemia nauplii) whilst in the gut cavity of the jellyfish. Underwater observations of giant jellyfish Nemopilema nomurai off Kyoto and Fukui prefectures revealed that approximately 30% of these jellyfish were accompanied by jack mackerel juveniles with body sizes ranging 10–45 mm standard length (SL). Considering that jack mackerel juveniles found in subtidal rocky reefs ranged 40–120 mm SL, we considered that jack mackerel from 10 to 45 mm SL associate with jellyfish as a hiding place as well as a food collector, until they find a suitable reef habitat when they attain approximately 40 mm SL.

Fish Fauna in the Gampo Sea of Gyeongju National Park

As part of the joint ecological research project in the Gyeongju National Park by the Korean Association of National Biodiversity on April 25-27 2007, the fishes in the Gampo waters were investigated on April 26 2007. The Gampo waters shows typical characteristics of the East Sea. A total of 2326 fishes in 37 species were discovered during the investigation period. The most dominant species was Trachurus japonicus, migratory fish, representing 85.2% of the total. With new discoveries of 10 species that have not been seen in the Gampo water, more accurate long-term studies can be carried out using diverse fishing gears.

Transport and survival processes of eggs and larvae of jack mackerel Trachurus japonicus in the East China Sea

Recent surveys showed substantial aggregation of larvae of jack mackerel in the southern East China Sea, indicating intensive spawning grounds near Taiwan. A numerical model was applied to investigate transport and survival processes of eggs and larvae of jack mackerel from the spawning area to the nurseries. The results show that: (i) the distributions of larvae simulated by the model agreed well with those obtained by field survey; (ii) the stock of jack mackerel in the Sea of Japan is composed of both groups from north of Taiwan and from the western coast of Kyushu. It takes more than two months for the former to reach the Sea of Japan, while it is within 40 days for the latter; and (iii) large proportions of the eggs and larvae spawned off the north of Taiwan are transported rapidly to the Pacific side of Kyushu by the Kuroshio Current, and the rest slowly to the east or north-east along the continental slope in the East China Sea. In contrast to the larval flux, survivors are more abundant in the northern East China Sea than in the Pacific Ocean, indicating that survival in the northern East China Sea would determine the jack mackerel stock in Japan.

Predator-specific growth-selective predation on larval Japanese anchovy Engraulis japonicus

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 350:99-107 (2007) - DOI: https://doi.org/10.3354/meps07158 Predator-specific growth-selective predation on larval Japanese anchovy Engraulis japonicus Akinori Takasuka1,*, Ichiro Aoki2, Yoshioki Oozeki1 1National Research Institute of Fisheries Science, Fisheries Research Agency, 2-12-4 Fukuura, Kanazawa, Yokohama, Kanagawa 236-8648, Japan 2Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan *Email: takasuka@affrc.go.jp ABSTRACT: Predator-specific growth-selective predation on larval Japanese anchovy Engraulis japonicus was demonstrated by comparing growth rates between the larvae ingested by predators and the larvae from the corresponding original populations through otolith microstructure analysis, based on original data and reanalyzed data from previous studies. Ingested larvae from the stomachs of small pelagic predators (juvenile Japanese anchovy, round herring Etrumeus teres, jack mackerel Trachurus japonicus and white croaker Pennahia argentatus) had significantly lower growth rates than the larvae from the original populations in general. For large piscivorous predators (sea bass Lateolabrax japonicus, greater amberjack Seriola dumerili and skipjack tuna Katsuwonus pelamis), no measurable differences in the growth rates were observed between ingested larvae and larvae from the original populations. Small pelagic fish were therefore identified as growth-selective predators, whereas large piscivorous fish were identified as non-growth-selective predators. Exponential declines in the relative predation mortalities of larvae with higher growth rates suggest the potential for growth rate to exert a great effect on recruitment variability. However, the predator field would regulate selection for growth characteristics of survivors. KEY WORDS: Growth-selective predation hypothesis · Growth rate · Otolith · Early life stage · Japanese anchovy · Relative predation mortality · Optimal foraging theory Full text in pdf format PreviousNextCite this article as: Takasuka A, Aoki I, Oozeki Y (2007) Predator-specific growth-selective predation on larval Japanese anchovy Engraulis japonicus. Mar Ecol Prog Ser 350:99-107. https://doi.org/10.3354/meps07158Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 350. Online publication date: November 22, 2007 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2007 Inter-Research.

Seasonal and interannual variation of subtidal fish assemblages in Wakasa Bay with reference to the warming trend in the Sea of Japan

A bi-monthly underwater visual census was conducted in the subtidal habitat of Nagahama, Wakasa Bay, Sea of Japan, over 5 years from January 2002 to December 2006. A total of 83 fish species and 63,328 individuals were recorded over 120 1-h visual censuses composed of three 2 × 200 m transects. The number of both total individuals (abundance) and species (richness) were strongly correlated with the bottom-water temperature. Species richness was greatest in summer (July–September), with 10–20 species per 400 m2, when the sea-bottom temperature was highest (24–28°C), and lowest in winter (January–March), with 1–8 species per 400 m2, when the temperature was lowest (10–12°C). Five species, i.e., rockfish, Sebastes inermis, wrasse, Pseudolabrus sieboldi, two species of goby, Acentrogobius pflaumii and Tridentiger trigonocephalus, and pygmy filefish, Rudarius ercodes, were frequently observed and present in more than 200 of the total of 360 total transects. While the presence of most fish species was dependent on water temperature, some species were independent of water temperature, including anchovy, Engraulis japonicus, S. inermis, wasp fish, Hypodytes rubripinnis, A. pflaumii and pufferfish, Takifugu poecilonotus. Jack mackerel, Trachurus japonicus, was the most abundant fish, being most typically seen from spring through autumn, with a total of 21,850 individuals observed over the whole census period. Some species showed strong annual fluctuations in abundance. The interannual stability in fish abundance and species richness was probably because the fish assemblage was composed of a sufficiently large number of species, but with the number of each species fluctuating over time. A comparison of the present survey to one in 1970–72 revealed that over the last 30 years southern fish species have significantly increased whereas those indigenous to northern waters have decreased.