scholarly journals The Role of Environmental Drivers in Humpback Whale Distribution, Movement and Behavior: A Review

2021 ◽  
Vol 8 ◽  
Author(s):  
Jan-Olaf Meynecke ◽  
Jasper de Bie ◽  
Jan-Lukas Menzel Barraqueta ◽  
Elisa Seyboth ◽  
Subhra Prakash Dey ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Water Movement ◽  
Humpback Whale ◽  
Humpback Whales ◽  
Environmental Drivers ◽  
Migration Routes ◽  
High Concentration ◽  
Chlorophyll A Concentration ◽  
Wide Range ◽  
The Relationship

Humpback whales, Megaptera novaeangliae, are a highly migratory species exposed to a wide range of environmental factors during their lifetime. The spatial and temporal characteristics of such factors play a significant role in determining suitable habitats for breeding, feeding and resting. The existing studies of the relationship between oceanic conditions and humpback whale ecology provide the basis for understanding impacts on this species. Here we have determined the most relevant environmental drivers identified in peer-reviewed literature published over the last four decades, and assessed the methods used to identify relationships. A total of 148 studies were extracted through an online literature search. These studies used a combined estimated 105,000 humpback whale observations over 1,216 accumulated study years investigating the relationship between humpback whales and environmental drivers in both Northern and Southern Hemispheres. Studies focusing on humpback whales in feeding areas found preferences for areas of upwelling, high chlorophyll-a concentration and frontal areas with changes in temperature, depth and currents, where prey can be found in high concentration. Preferred calving grounds were identified as shallow, warm and with slow water movement to aid the survival of calves. The few studies of migration routes have found preferences for shallow waters close to shorelines with moderate temperature and chlorophyll-a concentration. Extracting information and understanding the influence of key drivers of humpback whale behavioral modes are important for conservation, particularly in regard to expected changes of environmental conditions under climate change.

Chlorophyll-a Concentration Assessment Using Remotely Sensed Data over Multiple Years along the Coasts of the United Arab Emirates

2020 ◽  
pp. 345
Author(s):  
Eihab M. Fathelrahman ◽  
Khalid A. Hussein ◽  
Safwan Paramban ◽  
Timothy R. Green ◽  
Bruce C. Vandenberg
Keyword(s):  
Chlorophyll A ◽  
United Arab Emirates ◽  
Algal Blooms ◽  
Water Desalination ◽  
Least Square ◽  
Sufficient Information ◽  
Chlorophyll A Concentration ◽  
Explanatory Variables ◽  
Wide Range ◽  
Best Fit

The United Arab Emirates (UAE) recently witnessed algal/phytoplankton blooms attributed to the high concentrations of Chlorophyll-a associated with the spread and accumulation of a wide range of organisms with toxic effects that influence ecological and fishing economic activities and water desalination along coastal areas.  This research explores the UAE coasts as a case study for the framework presented here. In this research, we argue that advances in satellite remote sensing and imaging of spatial and temporal data offer sufficient information to find the best-fit regression method and relationship between Chlorophyll-a concentration and a set of climatic and biological explanatory variables over time. Three functional forms of regression models were tested and analysed to reveal that the Log-Linear Model found to be the best fit providing the most statistically robust model compared to the Linear and the Generalised Least Square models.  Besides, it is useful to identify the factors Sea Surface temperature, Calcite Concentration, Instantaneous Photosynthetically Available Radiation, Normalized Fluorescence Line Height, and Wind Speed that significantly influence Chlorophyll-a concentration. Research results can be beneficial to aid decision-makers in building a best-fit statistical system and models of algal blooms in the study area. The study found results to be sensitive to the study’s temporal time-period length and the explanatory variables selected for the analysis.

scholarly journals Assessing the potential of integrating Landsat sensors for estimating chlorophyll-a concentration in a reservoir

2017 ◽  
Vol 49 (5) ◽  
pp. 1608-1617 ◽  
Author(s):  
Matias Bonansea ◽  
Claudia Rodriguez ◽  
Lucio Pinotti
Keyword(s):  
Water Quality ◽  
Chlorophyll A ◽  
Landsat Imagery ◽  
Quality Parameters ◽  
Landsat 8 ◽  
Chlorophyll A Concentration ◽  
Chl A ◽  
Sensing Applications ◽  
Wide Range ◽  
Quality Assessments

Abstract Landsat satellites, 5 and 7, have significant potential for estimating several water quality parameters, but to our knowledge, there are few investigations which integrate these earlier sensors with the newest and improved mission of Landsat 8 satellite. Thus, the comparability of water quality assessing across different Landsat sensors needs to be evaluated. The main objective of this study was to assess the feasibility of integrating Landsat sensors to estimate chlorophyll-a concentration (Chl-a) in Río Tercero reservoir (Argentina). A general model to retrieve Chl-a was developed (R2 = 0.88). Using observed versus predicted Chl-a values the model was validated (R2 = 0.89) and applied to Landsat imagery obtaining spatial representations of Chl-a in the reservoir. Results showed that Landsat 8 can be combined with Landsat 5 and 7 to construct an empirical model to estimate water quality characteristics, such as Chl-a in a reservoir. As the number of available and upcoming sensors with open access will increase with time, we expect that this trend will certainly further promote remote sensing applications and serve as a valuable basis for a wide range of water quality assessments.

scholarly journals THE FLUCTUATION OF CHLOROPHYLL-A CONCENTRATION DERIVED FROM SATELLITE IMAGERY AND CATCH OF OILY SARDINE (SARDINELLA LEMURU0)IN BALI STRAIT

2010 ◽  
Vol 1 (1) ◽  
Author(s):  
J. LUMBAN GAOL ◽  
WUDIANTO ◽  
B. P. PASARIBU ◽  
D. MANURUNG ◽  
R. ENDRIANI
Keyword(s):  
Chlorophyll A ◽  
Satellite Imagery ◽  
Global Climate ◽  
Time Lag ◽  
Wide Field ◽  
Positive Anomaly ◽  
Chlorophyll A Concentration ◽  
Chl A ◽  
Acoustic Data ◽  
The Relationship

The investigation is aimed to know the relationship between chlorophyll-a (chl-a) concentration and the abundance of Oily sardine (Sardinella lemuru), in Bali Strait. A time series of monthly mean chl-a data derived from Ocean Color Thermal Scanner (OCTS) sensor and Sea-viewing Wide Field-of View Sensor (SeaWiFS) during 1997-1999 are used in this study. Monthly Sardinella lemuru catch during 1997-1999 are obtained from fish landing data. The abundance of Sardinella lemuru is determined from acoustic data conducted in Bali Strait in September 1998 and May 1999. The result shows that the fluctuation of chlorophyll-a concentration in Bali Strait is influenced by monsoon and global climate change phenomena such as Dipole Mode (DM) event. During southeast Monsoon the upwelling process occurred around Bali Strait, so that the chl-a concentration is increased and during DM event occurred positive anomaly of chl-a concentration. The catch of Sardinella lemuru in Bali Strait is fluctuated during 1997-1999. The correlation between chl-a concentration and lemuru catch is positive and significant with certain time lag. Key words: Chlorophyll-a, Sardinella lemuru, Bali Strait, Satellite imagery

Winter zooplankton dynamics in the English Channel and southern North Sea: trends and drivers from 1991 to 2013

2021 ◽  
Author(s):  
Tim Dudeck ◽  
Norbert Rohlf ◽  
Christian Möllmann ◽  
Marc Hufnagl
Keyword(s):  
Chlorophyll A ◽  
North Sea ◽  
Environmental Drivers ◽  
Zooplankton Abundance ◽  
English Channel ◽  
Study Region ◽  
Chlorophyll A Concentration ◽  
Southern North Sea ◽  
Zooplankton Ecology ◽  
Zooplankton Size

Abstract Winter has long been regarded as a period of minor importance in marine zooplankton ecology with static, low concentrations and growth rates of organisms. Yet, there is growing evidence that winter conditions influence spring bloom strength. With rising water temperatures, growing importance of fish larvae survival during winter and the lack of data to parameterize ecosystem models for this period, research focus shifted on winter zooplankton ecology. To enable looking into past changes in winter zooplankton ecology, we established a new winter zooplankton time series based on samples collected in the eastern English Channel and southern North Sea by the International Herring Larvae Survey since 1988. Four areas of the study region were identified containing different congregations of zooplankton. Overall, zooplankton size decreased while total zooplankton abundance increased, reaching its maximum in 2011. Zooplankton abundance dynamics were mainly related to temperature, chlorophyll a concentration and North Atlantic Oscillation index. Depth and Atlantic water inflow strongly influenced zooplankton size. Increased chlorophyll a concentration and high abundances of small copepods indicated bottom-up controlled secondary production since 2010 and a possible winter bloom in 2011. Based on the analysed parameters, no relation between herring larvae abundance and zooplankton or environmental drivers was determined.

ANALYSIS OF UTILIZATION CHLOROPHYLL-A CONCENTRATION DATA FROM REMOTE SENSING IMAGERY TO SUPPORT MARITIME SECURITY OPERATIONS (CASE STUDIES IN THE ARAFURA SEA)

JOURNAL ASRO ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 88
Author(s):  
Okol Sri Suharyo ◽  
Nawanto Budi Sukoco ◽  
Johar Setiadi ◽  
Eko Kurniawan
Keyword(s):  
Chlorophyll A ◽  
Satellite Image ◽  
Image Data ◽  
High Fertility ◽  
High Concentration ◽  
Concentration Data ◽  
Fishing Activity ◽  
Chlorophyll A Concentration ◽  
Operational Activities ◽  
Security Operations

Indonesia is the largest archipelago in the world with a vast ocean area and the richness of the fish. It allows theoccurrence of crime at sea, for example, is a crime of theft of fish and other marine resources. Indonesia in theregard Indonesian Navy confronted with various obstacles, among others, the limitation of the number of patrolboats that are not proportional to the extent of waters that should be on the cover as well as the limitations ofthe available budget for operational activities in the framework of the implementation of law enforcementoperations related crime at sea. With the limitation of that than required effectiveness and efficiency inoperations to crime at sea can still be implemented and the richness of the sea remains awake.The utilization ofremote sensing satellite technology capable of delivering information quickly with a broad scope. This researchuse the MODIS Aqua Image data Level 2 to detect the distributions of chlorophyll-a concentration which is anindicator of the fertility of the waters of an area the area is closely connected with the fisheries through theimplementations process of bottom-up areas with transparent high fertility rate is an area that's prone to fishtheft crime occurred. From the result of the data processing MODIS-Aqua Satellite image pattern time andlocation of the concentration of chlorophyll-a and verified by VMS data indicate that there is a close relationshipwhere a times and areas with a high concentration of chlorophyll observed a lot of fishing activity, so it is used inthis research can be used as supporting data in determining the direction and timing of the operation inparticular operations against crimes the theft of fish, finally the marine security operations could become moreeffective and efficient and success can be further improved.Keywords: Sea area, chlorophyll-a, effective and efficient.

scholarly journals Distribution and abundance of Euphausia mucronata: development stages and its relationship with temperature and chlorophyll-a concentration

2021 ◽  
Vol 49 (4) ◽  
pp. 640-648
Author(s):  
Pamela González ◽  
Armando Mujica ◽  
María Luisa Nava
Keyword(s):  
Low Temperature ◽  
Water Column ◽  
Chlorophyll A ◽  
Negative Correlation ◽  
Developmental Stages ◽  
Seawater Temperature ◽  
Chlorophyll A Concentration ◽  
Development Stages ◽  
Abundance And Distribution ◽  
The Relationship

Euphausia mucronata abundance and distribution of the developmental stages (calyptopis, furciliae, juveniles, and adults) was analyzed as a function of seawater temperature and chlorophyll-a concentration between Paposo (25°S) and Coquimbo (30°S), Chile. Zooplankton samples were obtained using bongo nets during February of three consecutive years (2014-2016). The Q coefficient was used to explore the relationship between the distribution and abundance of the development stages of E. mucronata with the temperature recorded throughout the water column. The adults were considerably more abundant than the rest of the ontogenetic development stages during the study period. The abundance of adults decreased from February 2014 to 2016, having a negative correlation with temperature. Relative abundance of juveniles and larvae increased positively related to the total euphausiid abundance. The Q coefficient showed a significant association of all development states concerning the low-temperature intervals recorded throughout the seawater column. Q coefficient showed no association with chlorophyll-a concentration through the recorded intervals throughout the water column and neither with the vertical abundance and distribution of E. mucronata specimens.

scholarly journals Very low numbers of endangered Oceania humpback whales seen in Fijian waters

2015 ◽  
Vol 33 (2) ◽  
pp. 39 ◽  
Author(s):  
C. Miller ◽  
A. Batibasiga ◽  
S. Sharma-Gounder ◽  
P. Solomona
Keyword(s):  
Southern Hemisphere ◽  
Humpback Whale ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Large Decrease ◽  
The South ◽  
Migration Routes ◽  
Antarctic Waters ◽  
Commercial Whaling

Intensive commercial whaling caused significant declines in Southern Hemisphere humpback whale (Megaptera novaeangliae) populations. In Fiji, land-based humpback whale surveys undertaken from 1956 to 1958 documented maximum weekly counts of more than 150 humpback whales in parts of the Bligh waters. These records provide an invaluable point of comparison to present-day observations as they occurred immediately prior to very large humpback whale catches in Antarctic waters to the south – and on potential migration routes – of humpback whales breeding in Fijian waters. We report here on a three-year (2010–2012) land-based survey also conducted in the Bligh waters during which a total of 33 individuals over 480 h were counted from Ovalau Island and 68 individuals over approximately 300 h were observed from Makogai Island. These findings suggest a large decrease in numbers of humpback whales seen in Fiji waters since commercial whaling operations.

scholarly journals Towards a merged satellite and in situ fluorescence ocean chlorophyll product

2012 ◽  
Vol 9 (6) ◽  
pp. 2111-2125 ◽  
Author(s):  
H. Lavigne ◽  
F. D'Ortenzio ◽  
H. Claustre ◽  
A. Poteau
Keyword(s):  
Chlorophyll A ◽  
Correction Coefficient ◽  
Data Set ◽  
Chlorophyll A Concentration ◽  
Profiling Float ◽  
In Situ Data ◽  
Biogeochemical Models ◽  
Wide Range ◽  
Similar Accuracy

Abstract. Understanding the ocean carbon cycle requires a precise assessment of phytoplankton biomass in the oceans. In terms of numbers of observations, satellite data represent the largest available data set. However, as they are limited to surface waters, they have to be merged with in situ observations. Amongst the in situ data, fluorescence profiles constitute the greatest data set available, because fluorometers have operated routinely on oceanographic cruises since the 1970s. Nevertheless, fluorescence is only a proxy of the total chlorophyll a concentration and a data calibration is required. Calibration issues are, however, sources of uncertainty, and they have prevented a systematic and wide range exploitation of the fluorescence data set. In particular, very few attempts to standardize the fluorescence databases have been made. Consequently, merged estimations with other data sources (e.g. satellite) are lacking. We propose a merging method to fill this gap. It consists firstly in adjusting the fluorescence profile to impose a zero chlorophyll a concentration at depth. Secondly, each point of the fluorescence profile is then multiplied by a correction coefficient, which forces the chlorophyll a integrated content measured on the fluorescence profile to be consistent with the concomitant ocean colour observation. The method is close to the approach proposed by Boss et al. (2008) to correct fluorescence data of a profiling float, although important differences do exist. To develop and test our approach, in situ data from three open ocean stations (BATS, HOT and DYFAMED) were used. Comparison of the so-called "satellite-corrected" fluorescence profiles with concomitant bottle-derived estimations of chlorophyll a concentration was performed to evaluate the final error (estimated at 31%). Comparison with the Boss et al. (2008) method, using a subset of the DYFAMED data set, demonstrated that the methods have similar accuracy. The method was applied to two different data sets to demonstrate its utility. Using fluorescence profiles at BATS, we show that the integration of "satellite-corrected" fluorescence profiles in chlorophyll a climatologies could improve both the statistical relevance of chlorophyll a averages and the vertical structure of the chlorophyll a field. We also show that our method could be efficiently used to process, within near-real time, profiles obtained by a fluorometer deployed on autonomous platforms, in our case a bio-optical profiling float. The application of the proposed method should provide a first step towards the generation of a merged satellite/fluorescence chlorophyll a product, as the "satellite-corrected" profiles should then be consistent with satellite observations. Improved climatologies with more consistent satellite and in situ data are likely to enhance the performance of present biogeochemical models.

scholarly journals Straight as an arrow: humpback whales swim constant course tracks during long-distance migration

2011 ◽  
Vol 7 (5) ◽  
pp. 674-679 ◽  
Author(s):  
Travis W. Horton ◽  
Richard N. Holdaway ◽  
Alexandre N. Zerbini ◽  
Nan Hauser ◽  
Claire Garrigue ◽  
...  
Keyword(s):  
Humpback Whale ◽  
Open Ocean ◽  
Sea Surface ◽  
Humpback Whales ◽  
Surface Currents ◽  
Migration Routes ◽  
Long Distance ◽  
Seasonal Migrations ◽  
Compass Mechanisms ◽  
Better Than

Humpback whale seasonal migrations, spanning greater than 6500 km of open ocean, demonstrate remarkable navigational precision despite following spatially and temporally distinct migration routes. Satellite-monitored radio tag-derived humpback whale migration tracks in both the South Atlantic and South Pacific include constant course segments of greater than 200 km, each spanning several days of continuous movement. The whales studied here maintain these directed movements, often with better than 1° precision, despite the effects of variable sea-surface currents. Such remarkable directional precision is difficult to explain by established models of directional orientation, suggesting that alternative compass mechanisms should be explored.

scholarly journals Distribution of chlorophyll-a concentration with the catch of julung fish in Ternate Island city

2018 ◽  
Vol 2 (1) ◽  
pp. 1 ◽  
Author(s):  
Aisyah Bafagih ◽  
Sahriar Hamzah ◽  
Umar Tangke
Keyword(s):  
Correlation Coefficient ◽  
Chlorophyll A ◽  
Coastal Waters ◽  
Gis Analysis ◽  
Chlorophyll A Concentration ◽  
Non Linear ◽  
The Relationship ◽  
Fishing Area

The study was conducted during March-May 2017 in the Coastal Waters of Ternate Island of North Maluku Province with the aim to study the relationship between the concentration of chlorophyll-a and the catch of Hemiramphus sp and its potential fishing area. Using experimental fishing method and non-linear regeneration analysis and GIS analysis. The result of this research shows that oceanographic factor that is chlorophyll-a concentration has significant effect on the catch of julung fish with correlation coefficient value of 0.729, with potential catch area located at three locations ie at coastal of Ngade to Kalumata on location 00o45'00"N - 127o21'03"E to 00o45'28.924"N - 127o22'08.893"E, coastal Keluarah Fitu at the location 00o44'39.490"N -127o19'51.083"E to 00o45'09.150"N - 127o20'52.263"E, and on the coast of Kelurahan Rua on location 00o45'51.169"N - 127o17'25.857"E to 00o46'42.457"N - 127o17'45.633"E.

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