Spanish Mackerel Scomberomorus Niphonius Research Articles

Otolith biogeochemistry reveals possible impacts of extreme climate events on population connectivity of a highly migratory fish, Japanese Spanish mackerel Scomberomorus niphonius

Otolith biogeochemistry reveals possible impacts of extreme climate events on population connectivity of a highly migratory fish, Japanese Spanish mackerel Scomberomorus niphonius

Interannual variability in otolith biogeochemical signatures of Japanese Spanish mackerel in the Yellow Sea

Fishes often use multiple habitats to complete their life cycles, leading to their unique otolith biogeochemical signatures. Interannual variability in otolith biogeochemical signatures is expected as fish respond to annual environmental variations in their distribution areas. In this study, we focus on Japanese Spanish mackerel Scomberomorus niphonius, an abundant commercial species in the Yellow Sea. As highly migratory fish that undergo their entire migratory cycle in a year, S. niphonius is susceptible to environmental variations. Consequently, they are believed to exhibit discernibly distinct migration patterns and varying timings of ontogenetic events across different years. Otolith biogeochemical signatures of 1-year-old spawning adults S. niphonius caught in the Yellow Sea from 2016 to 2018 were measured from core to edge using laser ablation inductively coupled plasma mass spectrometry (LAICP-MS). We hypothesized that the year-specific chemical signature could be found in 2016 as a strong El Niño Southern Oscillation event happened. From 2016 to 2018, converse ontogenetic changing patterns was observed for Sr/Ca and Ba/Ca, with Sr/Ca being positively correlated with sea surface salinity while Ba/Ca being negatively. As expected, the year-specific effect was identified for 2016 cohort but it was only significant on Ba/Ca. During this year, a stronger variation of elemental concentration and an earlier downward shift of Ba/Ca were found. These results provide evidence that otolith biogeochemical signatures have useful applications as natural tags, helping understand the interannual variability in migration of marine fish species.

Water temperature induced interannual variation in spawning of Japanese Spanish mackerel Scomberomorus niphonius in the northern Yellow Sea

Water temperature induced interannual variation in spawning of Japanese Spanish mackerel Scomberomorus niphonius in the northern Yellow Sea

Development of a prey-predator species distribution model for a large piscivorous fish: A case study for Japanese Spanish mackerel Scomberomorus niphonius and Japanese anchovy Engraulis japonicus

One of the major challenges of species distribution models (SDMs) is incorporating the influence of prey on the predator. An ensemble modeling approach, the prey-predator species distributabion model (PPSDM), uses environmental variables (sea surface temperature, bathymetry, sea surface salinity, and sea surface current) and a biotic variable (predicted prey distribution: Japanese anchovy) to predict a piscivorous fish (Japanese Spanish mackerel) habitat in the China Seas. PPSDM comprised selected preferable single algorithms from nine algorithms, including tree-based models, machine learning models, regression models, an envelope-style method, and a classification model. Compared with that obtained when using habitat without the Japanese anchovy distribution, the regression models, machine learning models and a classification model have significant improvements. However, tree-based models have only slightly improved. The PPSDM results well reflected the ontogenetic migration of Japanese Spanish mackerel. We found that the wintering ground was distributed in regions with temperatures between 11 and 17 °C and salinities between 33.6 and 34.1. The bottom topography was also closely correlated with Japanese Spanish mackerel, and the suitable habitat was at 50–100 m isobaths as topography determined the position of isotherms (11, 17 °C), salinity isolines (33.6, 34.1), and fronts (temperature, salinity) in winter. The relationships among different climatic indices, temperature, and Japanese Spanish mackerel were analyzed. We found that the East Asian monsoon significantly influenced the Japanese Spanish mackerel habitat by affecting temperature variation. In the future, the suitable habitat of Japanese Spanish mackerel is projected to decrease by 21%, 28%, 36%, and 42% under RCP2.6, RCP4.5, RCP6.0, and RCP8.5, respectively. The Japanese Spanish mackerel in the northern Yellow Sea is projected to experience the ‘cul de sac’ effect, which would drive this species toward local extinction. The Japanese Spanish mackerel in the China Seas will probably shift northeastward through the Tsushima Strait, and the Sea of Japan may form the main habitat at the end of the century.

Spawning overlap of Japanese anchovy Engraulis japonicus and Japanese Spanish mackerel Scomberomorus niphonius in the coastal Yellow Sea: A prey–predator interaction

AbstractJapanese Spanish mackerel Scomberomorus niphonius and Japanese anchovy Engraulis japonicus are typical predator and prey species, respectively, with high commercial values in the China seas. However, the interspecific interaction, particularly the relationship between the two species during early life stages, is unclear. Here, based on ichthyoplankton surveys in the coastal Yellow Sea during 2013–2018, we analyzed the relationship between the two species based on egg occurrence and abundance in the context of species interaction. Spawning optimal temperature were examined for anchovy (13.0–18.0°C) and mackerel (15.0–20.0°C) based on egg occurrences and abundances in relation to sea surface temperature. We confirmed the peak spawning periods (May and June) and primary spawning areas (Haizhou Bay) for both mackerel and anchovy based on spatiotemporal distributions of two species eggs. Mackerel showed a high spawning overlap with anchovy, and anchovy egg abundance were also higher in overlap areas. Anchovy egg abundance may be more important for mackerel spawning than environmental variables, suggesting the significance of prey for predators during early recruitment. The temperature also has important effects on mackerel spawning and could be a threshold affecting mackerel spawning activity. Mackerel might have evolved a spawning strategy of short‐term spawning timed to coincide with the peak spawning of anchovy in the coastal Yellow Sea. These results highlight the effects of interspecific relationships on spawning strategy of anchovy and mackerel in the coastal Yellow Sea and may provide some insights for early recruitment studies of piscivorous fishes in the context of the match–mismatch hypothesis.

The Effects of Selective Harvest on Japanese Spanish Mackerel (Scomberomorus niphonius) Phenotypic Evolution

Japanese Spanish mackerel (Scomberomorus niphonius) is an important fish species in the China Seas with wide distribution, extensive migration, and high economic value. This species has been yielding high fisheries production despite experiencing continuously high fishing pressure and the conversion from gillnet to trawl harvesting. Meanwhile, changes in life-history traits have been observed, including earlier maturation and smaller size at age. Here, we build an individual-based eco-genetic model parameterized for Japanese Spanish mackerel to investigate the population’s response to different fishing scenarios (fishing by trawl or by gillnet). The model allows evolution of life-history processes including maturation, reproduction and growth. It also incorporates environmental variability, phenotypic plasticity, and density-dependent feedbacks. Our results show that different gear types can result in different responses of life-history traits and altered population dynamics. The population harvested by gillnet shows weaker response to fishing than that by trawl. When fishing ceases, gillnet-harvested population can recover to the pre-harvest level more easily than that harvested by trawl. The different responses of population growth rate and evolution to different fishing gears demonstrated in this study shed light on the sustainable management and utilization of Japanese Spanish mackerel in the over-exploited China Seas.

Feeding ecology of Japanese Spanish mackerel (Scomberomorus niphonius) along the eastern coastal waters of China

Feeding ecology of Japanese Spanish mackerel (Scomberomorus niphonius) along the eastern coastal waters of China

High-temperature and starvation tolerances of juvenile Japanese Spanish mackerel Scomberomorus niphonius

Japanese Spanish mackerel Scomberomorus niphonius is a target species for stocking, but its biological characteristics at the juvenile stage are not well understood. Here, we investigated the high-temperature and starvation tolerances of hatchery-reared juveniles in captivity. We used juveniles of approximately 40 mm standard length, the size of juveniles released into the field. The upper incipient lethal temperature (50% lethal water temperature) was estimated to be 31.8 °C, higher than the maximum sea surface temperature in the field (approximately 29 °C). The critical thermal maximum was 34.8 °C, whereas it was 36.1 °C when juveniles were preliminarily acclimated to 31 °C for 24 h. Juveniles died from 3 to 11 days under nonfeeding conditions at 20 °C, but from 2 to 7 days at 27 °C. This information is expected to contribute to the development of the production of juvenile Japanese Spanish mackerel.

Effect of hot smoking treatment in improving Sensory and Physicochemical Properties of processed Japanese Spanish Mackerel Scomberomorus niphonius.

Japanese Spanish Mackerel (JSM) Scomberomorus niphonius (Cuvier 1832) is an important commercial fish species in South Korea. The postharvest handling, preservation, and storage of JSM have not been clearly understood, and therefore, it is very often oxidized to produce off‐flavor while marketed as the raw or frozen state. To overcome these problems, the present study was designed to adapt the hot smoke processing technique for improving the sensorial, physicochemical, and microbial qualities of JSM with extended shelf life. The hot smoking (70°C) with different sawdusts at the different smoke times (0, 20, 25, and 30 min) was applied to process JSM fillet. The smoked JSM obtained higher sensory attributes (appearance, odor, taste, color, texture, and overall preferences) and suppressed bacterial growth, pH, volatile base nitrogen, thiobarbituric acid‐reactive species, and trimethylamine N‐oxide at an optimum smoking time of 25 min using oak sawdust. Moreover, it possessed higher nutritional value and beneficial polyunsaturated fatty acids such as docosahexaenoic acid (DHA), 4.19 g/100 g, and eicosapentaenoic acid (EPA), 1.82 g/100 g. The smoked JSM product extended shelf life up to 42 days at 10°C storage temperature. The overall findings indicate that the hot smoking technology with JSM could be effective in achieving good sensorial, nutritional, and functional attributes to the consumer.

Molecular characterization of kisspeptin 2 dodecapeptide in sixteen species of Scombridae

Kisspeptin is an endogenous ligand that modulates gonadotropin-releasing hormone (GnRH) secretion and plays an essential role in the reproduction of mammals. In fish, two subtypes of kiss genes (kiss1 and kiss2), which encode kisspeptins, have been reported. Our previous study showed that kisspeptin 2 receptor (KissR2) is highly expressed in the vicinity of GnRH1 neurons, and that centrally administered Kiss2, but not Kiss1, significantly increased gonadotropin synthesis in chub mackerel Scomber japonicus. The results of this latter study suggested that the kisspeptin system plays an important role in chub mackerel reproduction, and that Kiss2 in particular plays a dominant role in the regulation of the central reproductive axis. In the present study, we identified the functional form of Kiss2 peptide in 16 species of Scombridae. All the species possessed kiss2, and the deduced mature peptide had 12 amino acids, all of which were very highly conserved, except for the second amino acid from the N-terminal end that was found to vary across species. However, species specificity of the second residue did not affect signal transduction in chub mackerel KissR2, bluefin tuna Thunnus orientalis KissR2, or Japanese Spanish mackerel Scomberomorus niphonius KissR2. Therefore, the importance of the Kiss2 system, shown in studies of chub mackerel reproduction, may be relevant across all species of Scombridae.

Stock Structure Analysis of the Japanese Spanish Mackerel Scomberomorus niphonius (Cuvier, 1832) Along the China Coast Based on Truss Network

The Japanese Spanish mackerel Scomberomorus niphonius (Cuvier, 1832) is widely distributed in the subtropical and temperate waters of the northwestern Pacific Ocean, supporting one of the most important commercial fisheries in China. However, ignoring the potential population structure changes induced by fishing pressure and climate change may undermine the population stability under the current management strategy. In this study, the population structure of the Japanese Spanish mackerel was investigated based on a morphometric truss network system. A total of 534 individuals were randomly collected from commercial gill nets spanning eight major spawning grounds in the Bohai, Yellow, and East China Seas during the peak spawning seasons respectively. A total of 17 measurements (including eye diameter) were conducted in each specimen and subjected to principal component analysis (PCA) and discriminant function analysis (DFA). The results of PCA indicated that the first two factors cumulatively caused 78.38% of the total morphometric variation and observable differences, primarily fin the caudal and trunk areas. The results of DFA revealed that the eight spawning groups can be divided into three stocks, i.e. , southern, middle, and northern stocks, with 68.7% of total accuracy. In contrast to previous studies, the spawning groups of the Japanese Spanish mackerel demonstrated a tendency to disperse to northern regions. In conclusion, this study found that to maintain the stability of the population structure and the total production of Japanese Spanish mackerel S. niphonius (Cuvier, 1832), a newly revised management method should be developed and implemented.

삼치 어육 가수분해물의 항산화 및 ACE 저해 활성

본 연구에서는 탈지 방법 및 가수분해 시간에 따른 삼치 어육의 항산화 및 ACE 저해 활성을 비교 분석하였다. 가수분해도는 탈지 후 익힘 익힘 후 탈지 생어육 탈지 순으로 높게 나타났으며, DPPH 라디칼 소거능은 5 mg/mL 농도에서 익힌 후 탈지 180분 가수분해물이 63.16%로 가장 높게 나타났다. 20 mg/mL에서는 탈지 후 익힘 180분 가수분해물이 89.47%로 가장 높았다. SOD 유사 활성은 가수분해 시간에 따라 활성이 증가하였으며 익힌 후 탈지 180분 가수분해물에서 가장 높은 활성을 나타내었다. 환원력의 경우 가수분해 전반부(30, 60분)에서 익힌 후 탈지 가수분해물이 가장 높은 활성을 나타내었으며, 2시간 후에는 생어육 탈지 가수분해물에서 높은 활성을 나타내었다. 아질산염 소거능은 pH 1.2에서 가장 높게 나타났으며, 그중 탈지 후 익힘 120분 가수분해물 50 mg/mL가 95.33%로 가장 높은 값을 나타내었다. ACE 저해 활성은 익힌 후 탈지 가수분해물이 높게 나타났으며, 탈지 후 익힘 처리군의 경우 가수분해도는 높게 나타났으나 익힌 후 탈지 처리군과 비교하여 동일 농도에서 낮은 활성을 나타내었다. 삼치 가수분해물의 경우 단백질가수분해 효소의 활성을 높이기 위해 탈지 과정이 필요하며, 탈지 과정을 가수분해 과정에 포함하고자 할 때 생어육에 비해 가열과정이 필요하다. 따라서 본 실험 결과를 검토하였을 때 탈지 후 가열과정을 거친 어육을 가수분해하는 것이 전반적으로 높은 활성을 나타내었다.

수산식품가공소재로서 시판 적색육 어류[고등어(Scomber japonicus), 삼치(Scomberomorus niphonius), 청어(Clupea pallasii)]의 화학적 위생특성

This study examined chemical characterization in commercial dark-fleshed fish (mackerel Scomber japonicus, Japa nese Spanish mackerel Scomberomorus niphonius, and Pacific herring Clupea pallasii) to determine their suitability for use as raw materials for seafood products. The volatile basic nitrogen (VBN), heavy metal, radioactivity, poly chlorinated biphenyl (PCBs), benzo[a]pyrene, and histamine concentrations were measured. The VBN in all of the dark-fleshed fish was less than 20 mg/100 g, which is the limit for raw materials for seafood processing. Except for mackerel based on the lead (Pb) standards of the European Union (EU), Taiwan, and CODEX, and all fish based on the cadmium (Cd) standards for China and the EU, the commercial dark-fleshed fish were free from total mer cury (Hg), Pb, and Cd based on domestic and foreign standards. The radioactivity, polychlorinated biphenyl (PCB), benzo[a]pyrene, and histamine concentrations of the commercial dark-fleshed fish all adhered to the domestic and foreign standards. The commercial dark-fleshed fish tested could all be used as raw materials for seafood products, except for some exported products.

어획특성을 이용한 삼치(Scomberomorus niphonius)의 회유경로 추정

Seasonal catch distributions of large purse seines and daily landings of coastal set nets were analyzed to understand the migration path of the Spanish mackerel Scomberomorus niphonius around Korean waters. The Spanish mackerel start to move toward the coastal region in the South and West Sea in May for spawning and stay until July, when spawning finishes. Afterwards, they start to migrate to the East China Sea and the southern East Sea and are found irrespective of the onshore and offshore regions. Therefore, they disappear from the offshore region during the spawning season in June and July, and a new recruitment population of age 0 begins to inflow into the coastal fishing grounds in the South Sea and West Sea in August, one month earlier than in the Japanese coastal region of the East Sea.

Population structure of Japanese Spanish mackerel Scomberomorus niphonius in the Bohai Sea, the Yellow Sea and the East China Sea: evidence from random forests based on otolith features

In this study, the population structure of Japanese Spanish mackerel Scomberomorus niphonius were investigated based on the geographical variation of otolith features, and the concept of random forests was introduced as a classifier. Samples were collected from eight main spawning grounds using commercial gill nets, covering the distribution range along the coast of China. Otolith shape was described by the shape variables and principle components of Fourier coefficients. Every possible combination of otolith variable was tested to search for an optimal variable combination. An intermediate number of variables (8 out of 13) produced the most discriminating signal, and then the eight grounds were divided into three stocks with 64.5 % global accuracy. The discriminant result provided phenotypic evidence for the common migration trajectory, and further confirmed the existence of a metapopulation in Japanese Spanish mackerel at a larger scale.

Age Composition of Japanese Spanish Mackerel Scomberomorus niphonius (Cuvier 1832) Caught off Hyogo Prefecture, South-western Sea of Japan, as Determined by the Otolith Cross-section Method

Age Composition of Japanese Spanish Mackerel Scomberomorus niphonius (Cuvier 1832) Caught off Hyogo Prefecture, South-western Sea of Japan, as Determined by the Otolith Cross-section Method

Preliminary Studies on Spanish Mackerel Fresh-Keeping Method in High-Voltage Electric Field

An innovative fresh-keeping method for aquatic products is presented in this article. Spanish mackerel (Scomberomorus niphonius) were treated with a high-voltage electric field (HVEF) at different voltages and times and then stored in a refrigerator at 4°C. Bacteria count, total volatile basic nitrogen (TVB-N), sensory index, proximate composition, and pH were measured to evaluate the fresh-keeping effect of the proposed method. Results indicate that HVEF can restrain bacteria growth, reduce TVB-N, and delay sensory score decline; and that 45 kV for 20 min is the optimal treatment parameter of HVEF for extending Spanish mackerel shelf life. Results also suggest a potential application for HVEF treatment in aquatic products preservation.

サワラ仔魚における耳石透明帯と不透明帯の形成時間

飼育下のサワラ仔魚について 24 時間にわたって 3 時間ごとに標本のサンプリングを行い，扁平石の透明帯と不透明帯が形成される時間帯を調べた。初生輪は 5 日齢に形成され，摂餌開始日と一致していた。透明帯の形成は 05:00～08:00 の間に始まり，日中から夜間にかけて継続し，不透明帯はその後夜間に形成された。この結果は耳石の最外縁に観察される日周輪の読み取り精度を向上させるための有効な情報であり，天然で採集されたサワラ仔魚の耳石日周輪解析を行う際に採集時間を考慮することによって，より正確な判断が可能となる。

Ecological interactions between hatchery and wild fish: a case study based on the highly piscivorous Japanese Spanish mackerel

If the release of hatchery-reared juveniles exceeds the carrying capacity of the envi- ronment, the growth rate of wild fish may decrease or hatchery fish might displace wild fish because of competition for prey and space, or cannibalism. However, limited evidence is available to confirm these ecological effects. Therefore, we used census-marking experiments to investigate the ecological interactions between hatchery and wild fish in the large piscivorous species Japan- ese Spanish mackerel (JSM) Scomberomorus niphonius in the Seto Inland Sea. We analysed the relationship between the mean body weight and population size of Age 0 JSM, and the relation- ship between the biomass of juvenile Japanese anchovy Engraulis japonicus, which is the princi- pal prey fish of JSM, and that of Age 0 JSM. We also estimated the spawner−recruit relationship. We measured the body sizes of 5008 JSM juveniles during July and December between 1999 and 2005 in the eastern Seto Inland Sea, and 551 hatchery fish were identified in the sample based on examinations of marked otoliths. There was a negative correlation between the mean body weight and population size of Age 0 fish, which clearly demonstrated the density-dependent growth of Age 0 JSM. The ~35% variation in the biomass of Age 0 JSM was explained by the biomass of prey fish. Hatchery fish tended to be larger than wild fish, and they had better growth perform- ance. Our analysis showed that hatchery fish reduced the growth rate of wild fish and displaced the wild fish in terms of biomass when hatchery fish stocking exceeded the carrying capacity of the environment.

Deformity of the inter-nostril epidermis in artificially raised Japanese Spanish mackerel Scomberomorus niphonius juveniles

Deformity of the inter-nostril epidermis in artificially raised Japanese Spanish mackerel Scomberomorus niphonius juveniles