Acoustic Assessment of Populations of Common Dolphin off the West Wales Coast, With Perspectives from Satellite Infrared Imagery

1998 ◽  
Vol 78 (4) ◽  
pp. 1353-1364 ◽  
Author(s):  
John C. Goold
Keyword(s):  
Marked Decrease ◽  
Sea Surface ◽  
Common Dolphin ◽  
Survey Area ◽  
Entire Region ◽  
The West ◽  
Acoustic Contact ◽  
Time Of Year ◽  
Passive Acoustic ◽  
Common Dolphins

Passive acoustic monitoring of common dolphins was conducted across a survey area of 1000 n.m.2 (nautical miles) off the west Wales coast during the months September, October, November and December 1995. Dolphin presence and distribution was assessed by a system of percentage acoustic contact. Results were compared with those from a seismic/dolphin survey during the same months of the previous year, and across the same survey area. Distributions of common dolphins within the survey area showed similar trends for both years, with a marked decrease in dolphin contacts between September and October of both years. These observations suggest offshore migration of common dolphin populations at the time of year. Sea surface temperature distribution across the entire region was visualized during two survey periods using infrared satellite imagery. It is hypothesized from these observations that offshore migration of common dolphins coincides with a break-up of the Celtic Sea Front, a distinct oceanographic feature which crosses the survey area.

Acoustic Assessment of Populations of Common Dolphin Delphinus Delphis In Conjunction With Seismic Surveying

1996 ◽  
Vol 76 (3) ◽  
pp. 811-820 ◽  
Author(s):  
John C. Goold
Keyword(s):  
Seismic Survey ◽  
Avoidance Reaction ◽  
Common Dolphin ◽  
Survey Area ◽  
Delphinus Delphis ◽  
Air Gun ◽  
Before And After ◽  
Seismic Surveying ◽  
Acoustic Contact ◽  
Common Dolphins

Common dolphin, Delphinus delphis (bairdi), were monitored acoustically across a survey area of 2747 km2 during a three month period before, during and after an oil industry two dimensional (2D) seismic reflection survey. Over 900 h of audio survey data were collected and analysed, along with GPS positional data, to reveal trends in presence and distribution of animals. The presence of dolphins was determined from vocalization events on the survey recordings. Dolphin presence was assessed by a system of percentage acoustic contact. This was highest before and after the seismic survey, with common dolphins showing a clear south-westerly skew within the survey area and a probable south-westerly migration of animals between September and December. Acoustic contact with dolphins during the seismic survey also showed a south-westerly skew within the survey area, although percentages were lower. Monitoring during the period of seismic activity was restricted to the immediate vicinity (1–2 km) of the seismic vessel, so percentage contact most likely reflects the response of dolphins to such immediate activity. The overall result suggests an avoidance reaction by common dolphins to air gun emissions, although certain observations suggest tolerance to these sounds outside a 1 km radius of the guns.

TEMPERATURE VARIABILITY AT SENUNU BAY, WEST SUMBAWA

2013 ◽  
Vol 5 (2) ◽  
Author(s):  
Syamsul Hidayat ◽  
Mulia Purba ◽  
Jorina Waworuntu
Keyword(s):  
Layer Thickness ◽  
Mixed Layer ◽  
Cross Correlation ◽  
Sea Surface ◽  
Thermocline Depth ◽  
Kelvin Wave ◽  
The West ◽  
Sea Bottom ◽  
Annual Period ◽  
Regional Processes

The purposes of this study were to determine the variability of temperature and its relation to regional processes in the Senunu Bay. The result showed clear vertical stratifications i.e., mixed layer thickness about 39-119 m with isotherm of 27°C, thermocline layer thickness about 83-204 m with isotherm of 14–26°C, and  the deeper layer from the thermocline lower limit to the sea bottom with isotherm <13°C. Temperature and the thickness of each layers varied with season in which during the Northwest Monsoon the temperature was warmer and the mixed layer was thicker than those during Southeast Monsoon. During Southeast Monsoon, the thermocline layer rose  about 24 m. The 2001, 2006, and 2009 (weak La Nina years),  the Indonesia Throughflow (ITF) carried warmer water, deepening thermocline depth and reducing upwelling strength.  In 2003 and 2008 thickening of mixed layer occurred in transition season  was believed  associated with the  arrival of Kelvin Wave from the west. In 2002 and 2004 (weak El Nino period,) ITF carries colder water shallowing thermocline depth and enhancing upwelling strength. In 2007 was believed to be related with positive IODM where the sea surface temperature were decreasing due to intensification of southeast wind which induced strong upwelling. The temperature spectral density of mixed layer and thermocline was influenced by annual, semi-annual, intra-annual and inter-annual period fluctuations. The cross-correlation between wind and temperature showed significant value in the annual period.  Keywords: temperature, thermocline, variability, ENSO, IODM.

Chemical and microbiological studies of sea-surface films in the Southern Gulf of California and off the West Coast of Baja California

1986 ◽  
Vol 19 (1) ◽  
pp. 17-98 ◽  
Author(s):  
P.M Williams ◽  
A.F Carlucci ◽  
S.M Henrichs ◽  
E.S Van Vleet ◽  
S.G Horrigan ◽  
...  
Keyword(s):  
West Coast ◽  
Gulf Of California ◽  
Baja California ◽  
Sea Surface ◽  
Surface Films ◽  
The West

Evaluation of Satellite-Derived SST Products in Identifying the Rapid Temperature Drop on the West Florida Shelf Associated With Hurricane Irma

2018 ◽  
Vol 52 (3) ◽  
pp. 43-50 ◽  
Author(s):  
Yonggang Liu ◽  
Robert H. Weisberg ◽  
Jason Law ◽  
Boyin Huang
Keyword(s):  
Temperature Drop ◽  
Coastal Ocean ◽  
Sea Surface ◽  
West Florida Shelf ◽  
The West ◽  
Florida Shelf ◽  
Time Period ◽  
Rapid Temperature ◽  
Ocean Observations ◽  
Hurricane Irma

AbstractSatellite-derived daily sea surface temperature (SST) products are compared with moored SST observations on the West Florida Shelf during the time period of Hurricane Irma. Most of the SST products compare reasonably well with the moored data at the location of 25-m depth, where SST dropped by about 1°C after the hurricane passage. However, most of the SST products did not show the rapid SST drop at the location of 50-m depth where the surface water was cooled by about 4°C within 1 day in response to the hurricane passage. This finding has important implications to air-sea interaction studies and hurricane simulations, in which SST data play an important role. The limitations of the popular satellite products call for additional coastal ocean observations as well as proper inclusion of the real-time observations in satellite-derived products.

scholarly journals Variasi Musiman Hubungan Antara Parameter Oceanografi Dengan Hasil Tangkapan Ikan Tongkol Berdasarkan Data Harian Di Selat Bali

2017 ◽  
Vol 4 (1) ◽  
pp. 109 ◽  
Author(s):  
I Gusti Agung Bagus Wisesa Sastra ◽  
I Wayan Gede Astawa Karang ◽  
Abd. Rahman As-syakur ◽  
Yulianto Suteja
Keyword(s):  
Chlorophyll A ◽  
Environmental Parameters ◽  
Pelagic Fish ◽  
Sea Surface ◽  
Fishing Ground ◽  
Temporal Fluctuation ◽  
Simple Correlation ◽  
The West ◽  
Chlorophyll A Concentration ◽  
Fish Catch

Mackerel fish that classified pelagic fish and an export commodity in Indonesia. Distribution of mackerel fish are foundn all Indonesian waters, one of them in the Bali Strait. Distribution of mackerel fish influenced by oceanographic condition such as sea surface temperature (SST) and chlorophyll-a concentration. SST and chlorophyll-a concentrations are environmental parameters that can provide information on fishing ground. The purpose of this research is explained the temporal fluctuation and relationship between SST and chlorophyll-a concentration with mackerel fish had been catch in Bali Strait waters during 2011-2016. Data were analyzed using simple correlation analysis with 95% confidence interval. Temporally, the highest average SST occurred during the transition season I (March-May) and the lowest in the east season (June-August). The highest average chlorophyll-a concentration occurs in the east season and the lowest in the west season (December-February). The highest catch of mackerel fish occurred during transitional season II (September-November) and lowest in west season. The association between SST and chlorophyll-a concentration on mackerel fish catch showed low correlation with significant relationship, whereas concentration between SST and chlorophyll-a concentration strong with significant correlation

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