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Estimation of αco2 and pKapp of hemolymph acid–base balance in Mytilus coruscus between 16℃ and 28℃
Full text linkThe influence of temperature on the hemolymph CO2 solubility coefficient (αco2) and the apparent dissociation constant of carbonic acid (pKapp) in Mytilus coruscus was investigated. Mytilus coruscus hemolymph was equilibrated with standard CO2 gas mixtures to obtain expressions for αco2 and pKapp as a function of temperature.The relationship between αco2 and temperature (T) is expressed as follows: αco2 = 138.247 – 11.253 • T + 0.554 •T2 − 0.0140 • T3 + 0.000138 • T4. The following relationship between pKapp and temperature was found: pKapp =6.6407 – 0.01589 • T . The parameter units are ℃ for T and µM/L/torr for αco2. These equations enable estimation of hemolymph αco2 and pKapp at arbitrary temperatures and simple calculation of Pco2 and [HCO3–].イガイの呼吸機能，特に酸塩基平衡を評価するため，イガイ閉殻筋から採取したヘモリンパ液を用いて，二酸化炭素溶解度（αco2）と炭酸解離恒数（pKapp）に及ぼす温度の影響について調査した。各実験温度において，イガイのヘモリンパ液を二酸化炭素標準ガスと平衡させ，pHと全炭酸含量を測定し，温度（T）とαco2あるいはpKappとの関係を分析したところ，以下の関係式を得た。αco2 = 138.247 – 11.253 • T + 0.554 • T2 − 0.0140 • T3 +0.000138 • T4，pKapp = 6.6407 − 0.01589 • T（αco2: µM/L/torr; T: ℃）。これらの式により，任意の温度でイガイのヘモリンパ液におけるαco2とpKappの推定が可能となった。これら推定値を用いれば，微量なヘモリンパ液の二酸化炭素分圧や炭酸水素イオン濃度を任意の温度で把握することができるだろう。編集：水産大学校departmental bulletin pape
Morphological characteristics of cyclostom neutrophils observed by Artur Pappenheim
Full text linkArtur Pappenheim reported a poor description of the morphology of blood neutrophils from lamprey (Lampetra planeri; adult and ammocoetes) and hagfish (Myxine glutinosa) in Folia Haematologica (volume 8, 1909). Here, we inferred on the morphological characteristics of cyclostome neutrophils observed by Pappenheim based on his descriptions and our previous reports. He recognized neutrophilic leukocytes (mature neutrophils) in lamprey (adult and ammocoetes) and hagfish, and neutrophilic myelocytes (immature neutrophils) in ammocoetes and hagfish. This means the existence of specific granules and azure granules. However, the specific granules were considered as an inner layer (L0) of the striated granule (NG2), and the azure granules outer (L1) layer of the striated granule (NG2). The specific granules (=L0 of NG2) would probably have been stained with triacid (purple), acid dyes, and May-Grünwald·Giemsa (MGG; purple), but not with methylgreen-pyronine (MP). The azure granules (=L1 of NG1a) would also have stained purple with MGG, but negative with triacid, acidic dyes and MP.編集：水産大学校departmental bulletin pape
Horizontal distribution and abundance of red seabream (Pagrus major) in the East China Sea and Sea of Japan based on standardized catch per unit effort
Full text linkRed seabream (Pagrus major) is an important fisheries species in Japan, where it has been managed since 2025. Accurate stock assessment is necessary for rational fisheries management, and catch per unit effort (CPUE) is one of the key indexes used for this purpose. In the present study, the CPUE of red seabream in the East China Sea and Sea of Japan was standardized by incorporating seawater temperature and salinity based on fishing data obtained from bottom trawlers operating in key fishing grounds in these regions. We used data from operation reports available from 1982 to 2022, including fishing positions and efforts during each cruise and incorporated temperature and salinity data into the model from 1993. We applied a delta log-normal model for CPUE standardization and revealed an increase in this index since the early 1990s. We examined the horizontal distribution patterns of red seabream in each fishery grid that is 30 × 30 min latitude and longitude, and observed that the high-CPUE area extended northeastward from Taiwan to Japan along the shelf edge, which corresponds to the main fishing grounds covered by Japanese fleets after 2000. The probability of presence of red seabream increased drastically when water temperature at a depth of 50 m exceeded 15 °C. The reasons for the observed stock fluctuations may be a reduction in fishing pressure and warming seawater temperature.journal articl
Structures and seasonal changes of annual Zostera marina population in Tategami-ura, Ago Bay, Mie Prefecture, central Japa
Full text linkThis study clarified the structures and seasonal changes of the annual Zostera marina population from April 2003 to November 2004, growing at Tategami-ura, Ago bay, Mie prefecture. Productive structures showed the graminous types excluding flowering period (May-June). Biomass and shoot density reached maximum values in May-June. At that time, over 80% of shoots were flowering shoots. And then, all shoots were disappeared in summer. From October-November, a lot of seedlings recruited and grew to flowering shoots by next spring. Maximum daily net production showed 4.50 g m-2 day-1 in June, which was similar level to that of the perennial Zostera marina population. However, yearly net production (305.0 g m-2 year-1) showed lower than that of the perennial type. Yearly maximum biomass was 152.6 g m-2, and production/biomass (P / B) ratio was 2.0. It is necessary to more research in the production because the biomass and shoot density of the annual population verify drastically year to year.本研究では，2003年4月から2004年11月において三重県英虞湾立神浦に生育する一年生アマモ群落の構造と季節変動を明らかにした。生産構造は，開花期 (5～6月) を除いてイネ科型を示した。現存量およびシュート密度は5～6月に最大値を示し，密度の80%以上が花枝であった。また，夏季には全てのシュートが消失した。10～11月にかけては多くの実生が加入し，翌春までに生殖シュートへと生長した。6月に日純生産量は4.50 g m-2 day-1と最大値を示し，多年生アマモ群落と同程度であった。しかし，年間純生産量 (305.0 g m-2 year-1) は多年生アマモ群落よりも低かった。年間最大現存量は152.6 g m-2であり，年間純生産量と年間最大現存量の比 (P / B比) は2.0であった。一年生アマモ群落は現存量およびシュート密度が毎年大きく変動するため，生産量に関する研究をさらに進める必要がある。編集：水産大学校departmental bulletin pape
Protist dynamics in the eastern Tsugaru Strait, Japan from 2010 to 2018: Implications for the relationship between decadal climatology and aquaculture production
Full text linkEnvironmental changes such as seasonality, decadal oscillation, and anthropogenic forcing may shape the dynamics of lower trophic-level organisms. In this study, 9-years (2010–2018) of monitoring data on microscopic protists such as diatoms and dinoflagellates, and environmental variables were analyzed to clarify the relationships between plankton and local/synoptic environmental changes. We found that time-series temperature increased in May, whereas it decreased in August and November. Nutrients (e.g., phosphate) decreased in May, remained unchanged in August, and increased in November from 2010 to 2018. The partial pressure of CO2 increased in May, August, and November over time. It is notable that the change in seawater temperature (−0.54 to 0.32 °C per year) and CO2 levels (3.6–5.7 μatm CO2 per year) in the latest decade in the eastern Tsugaru Strait were highly dynamic than the projected anthropogenic climate change. Protist abundance generally increased or stayed unchanged during the examined period. In August and November, when cooling and decreases in pH occurred, diatoms such as Chaetoceros subgenus Hyalochaete spp. and Rhizosoleniaceae temporally increased from 2010 to 2018. During the study period, we found that locally aquacultured scallops elevated soft tissue mass relative to the total weight as diatom abundance increased, and the relative scallop soft tissue mass was positively related to the Pacific Decadal Oscillation index. These results indicate that decadal climatic forcing in the ocean modifies the local physical and chemical environment, which strongly affects phytoplankton dynamics rather than the effect of anthropogenic climate change in the eastern Tsugaru Strait.journal articl