scholarly journals First report of a rare bloom of Ornithocercus magnificus, Stein 1883 along the coastal waters of Kochi; A possible indicator of increasing sea surface temperature

2020 ◽  
Vol 62 (2) ◽  
pp. 92-98
Author(s):  
Lavanya Ratheesh ◽  

2018 ◽  
Vol 11 (1) ◽  
pp. 5 ◽  
Author(s):  
R. Susanto ◽  
Jiayi Pan ◽  
Adam Devlin

Tidal mixing in the coastal waters of Hong Kong was investigated using a combination of in situ observations and high-resolution satellite-derived sea surface temperature (SST) data. An indicator of tide-induced mixing is a fortnightly (spring-neap cycle) signature in SST due to nonlinear interactions between the two principal diurnal and the two principal semi-diurnal tides. Both semi-diurnal and diurnal tides have strong tidal amplitudes and currents near Hong Kong. As a result, both the near-fortnightly (Mf) and fortnightly (MSf) tides are enhanced due to nonlinear tidal signal interactions. In addition, these fortnightly tidal signals are modulated by seasonal variability, with the maximum seasonal modulation of fortnightly tides occurring during the monsoon transition periods in May and October. The largest fortnightly signals are found in the southwestern part of the Pearl River estuary. Tidal constituent properties vary by space and depth, and high-resolution SST plays a pivotal role in resolving the spatial characteristics of tidal mixing.





2018 ◽  
Vol 23 (4) ◽  
pp. 275 ◽  
Author(s):  
Komang Iwan Suniada ◽  
Eko Susilo

Perikanan pelagis di perairan Selat Bali telah diusahakan sejak lama. Data runtut tahun hasil tangkapan yang didaratkan cenderung berfluktuasi. Kajian ini bertujuan untuk mengetahui kondisi spasial dan temporal karakteristik oseanografi, terkait dengan dengan dinamika perikanan pelagis di Selat Bali. Data parameter oseanografi meliputi suhu permukaan laut (SPL) dan klorofill-a (chl-a) yang diperoleh dari citra satelit penginderaan jauh Aqua/Terra MODIS, sedangkan data sumberdaya perikanan pelagis berupa hasil tangkapan/satuan upaya (Catch per Unit Effort, CPUE) ikan pelagis diperoleh dari Tempat Pendaratan Ikan (TPI) Pengambengan, Jembrana - Bali pada periode Januari 2007 hingga Desember 2015. Uji statistik regresi linear berganda digunakan untuk mengetahui pengaruh parameter oseanografi terhadap kondisi perubahan sumberdaya perikanan pelagis. Sebaran spasial SPL menunjukkan bahwa pada Mei hingga November suhu permukaan laut cenderung rendah serta tidak ada perbedaan yang signifikan antara suhu di perairan pantai dan di laut lepas. Secara temporal terlihat bahwa suhu terendah terjadi pada musim timur yaitu pada Agustus 2007. Sebaran spasial chl-a menunjukkan bahwa peningkatan konsentrasi chl-a dimulai dari Mei hingga Oktober serta terdapat perbedaan yang signifikan antara chl-a perairan pantai dan laut lepas. Secara temporal terlihat bahwa konsentrasi chl-a tertinggi terjadi pada Oktober 2015. Faktor iklim yang merupakan faktor eksternal memberikan pengaruh terhadap perubahan konsentrasi chl-a pada lokasi penelitian. Faktor iklim tersebut adalah kecepatan angin dan kejadian El-Nino. Hasil analisis statistik menunjukkan bahwa perubahan parameter SPL dan chl-a secara bersama-sama berpengaruh signifikan terhadap perubahan CPUE ikan pelagis, namun secara parsial parameter chl-a memberikan pengaruh yang lebih signifikan dibandingkan dengan parameter SPL.Pelagic fisheries around Bali Strait have been exploited since decades. Based on monthly and annual landing data, fish production around Bali strait are very fluctuated. This study aims to determine the spatial and temporal conditions of oceanographic characteristics and how they relate to the dynamics of pelagic fisheries in the Bali Strait. The oceanographic parameter data consist of sea surface temperature (SST) and chlorophyll-a (chl-a) that obtained from Aqua / Terra MODIS remote sensing satellite imagery, while the dynamics of pelagic fish resource data indicated by Catch per Unit Effort (CPUE) derrived from landing place (TPI) Pengambengan, Jembrana - Bali in the period January 2007 to December 2015. Multiple linear regression analysis were applied to determine the effect of oceanographic parameters on the changing conditions of pelagic fishery resources. Spatial distribution of SPL indicates that in May to November sea surface temperature tends to be low and there is no significant difference between the temperature in coastal waters and on high seas. The temporal distribution shows that the lowest temperature occurred during the southeast monsoon in August 2007. The spatial distribution of chl-a showed that the chl-a concentration starts to increase from May to October and there were significant differences between chl-a coastal waters and high seas. The temporal distribution shows that the highest chl-a concentration occurred in October 2015. Climate factor which is an external factor has an effect on the change of chl-a concentration at the research location. Climatic factors are wind speed and El-Nino events. The result of the statistical analysis shows that the change of SPL and chl-a parameters together significantly influence on the CPUE of pelagic fish, but partially chl-a parameter gives highly significant effect than SST parameter.



Author(s):  
Hasan Sitorus ◽  
Zulham Apandy Harahap ◽  
Tifani Zianida

The east coast of North Sumatra is part of the Malacca Strait, a highly utilized fishing area. One of the commodities that can be harvested is the Yellowstripe Scad (Selaroides leptolepis). Through oceanography parameters, specifically temperature and chlorophyll-aconcentrations, it is possible to determine optimal fishing grounds which can be used as guidelines. One of the satellites that can detect sea surface temperature (SST) and chlorophyll-a concentrations is Aqua (EOS PM),which is equipped with a Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Data on the Yellowstripe Scad (Selaroide sleptolepis) were obtained from the Belawan Ocean Fishing Port (OFP). Based on the analysis of MODIS images from the Aqua satellite, the sea surface temperature of theeast coastal waters of North Sumatra in 2012 - 2016 ranged from 29oC – 32oC with chlorophyll-a concentrations ranging from 0.19 - 5.26 mg/m³. The largest harvest occurred during the west monsoon with a value of 143.46 tons and the lowest was during the east monsoon with a value of 139.87 tons. Yellowstripe Scad harvest has a negative correlation with the sea surface temperature with a correlation value of -0.365. Chlorophyll-a concentrations and harvest amount have a positive correlation value of 0.660. Yellowstripe Scad is predicted to yield the largest harvest during the west monsoon (December-February) between the Asahan and Labuhanbatu Regencies at coordinates 2.68oN - 2.74oN and 100.37oE - 100.44oE.





Author(s):  
Yanling Hao ◽  
Tingwei Cui ◽  
Vijay P. Singh ◽  
Jie Zhang ◽  
Ruihong Yu ◽  
...  


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