scholarly journals GIS based mapping of spatio-temporal distribution pattern of ribbonfish Trichiurus lepturus (Linnaeus, 1758) along Saurashtra coast, India

2016 ◽  
Vol 63 (4) ◽  
Author(s):  
P. Abdul Azeez ◽  
K. Mohammed Koya ◽  
K. L. Mathew ◽  
G. S. Temkar ◽  
R. A. Khileri
Keyword(s):  
Fishery Management ◽  
Stock Assessment ◽  
Temporal Distribution ◽  
Fundamental Information ◽  
Trichiurus Lepturus ◽  
Saurashtra Coast ◽  
Management Plans ◽  
Spatio Temporal ◽  
Gis Software ◽  
Fishing Area

Identification of spatio-temporal distribution of fish species represents fundamental information for stock assessment which in turn is essential for formulation of fishery management plans as well as for GIS based decision making. This study investigated the spatio-temporal distribution and abundance of different life stages of ribbonfish, Trichiurus lepturus (Linnaeus, 1758) off Saurashtra coast. Geographical coordinates of fishing and allied information on the time of fishing, depth of the fishing area as well as catch details were collected using a structured schedule, from selected trawlers operated from Veraval. Information was mapped using a GIS software to get the spatio-temporal distribution of the species. It was observed that juveniles were more abundant along the south Saurashtra coast whereas subadults and adults showed a discontinuous distribution with abundance in the waters off south Saurashtra as well as north Saurashtra coasts.

scholarly journals Assessing precipitation distribution impacts on droughts on the island of Crete

2012 ◽  
Vol 12 (4) ◽  
pp. 1159-1171 ◽  
Author(s):  
A.-E. K. Vrochidou ◽  
I. K. Tsanis
Keyword(s):  
Standardized Precipitation Index ◽  
Temporal Distribution ◽  
Mean Annual Precipitation ◽  
Drought Duration ◽  
Precipitation Distribution ◽  
Management Plans ◽  
Drought Pattern ◽  
Spatio Temporal ◽  
Precipitation Records ◽  
High Elevations

Abstract. Precipitation records from 56 stations on the island of Crete (Greece) revealed that areal mean annual precipitation is of a strong orographic type and its magnitude decreases in west-east direction by as much as 400 mm on average. Amongst many parameters that influence precipitation, the elevation and longitude were the most important and provided the highest spatial correlation. It was found that during the year with minimum precipitation, the precipitation shortage was greater at high elevations while the precipitation excess during the year with maximum precipitation was greater in the western part of the island. The assessment of the spatial and temporal distribution of droughts was carried out with the aid of the Spatially Normalized Standardized Precipitation Index (SN-SPI) for the period 1974–2005 in order to compare drought conditions between neighbouring areas of differing precipitation heights. The analysis showed that severe droughts occurred around the year 1992–1993, with a duration of up to 3 yr. Multiple linear regression (MLR) modeling of precipitation in conjunction with cluster analysis of drought duration exhibits the linkage between precipitation, droughts and geographical factors. This connection between spatial precipitation distribution and geographical parameters provides an important clue for the respective spatial drought pattern. The above findings on the spatio-temporal drought distribution will update the current~drought management plans by developing more precise drought warning systems.

scholarly journals THE IMPACT OF ENVIRONMENTAL CHANGES ON BLACK MARLIN, Makaira indica (Cuvier, 1832) ABUNDANCES IN THE EASTERN INDIAN OCEAN

2020 ◽  
Vol 26 (1) ◽  
pp. 41
Author(s):  
Bram Setyadji ◽  
Zulkarnaen Fahmi
Keyword(s):  
Indian Ocean ◽  
Fishery Management ◽  
Environmental Changes ◽  
Stock Assessment ◽  
Sea Surface ◽  
Main Driver ◽  
Spatio Temporal ◽  
Standardized Index ◽  
By Catch ◽  
The Impact

Black marlin (Makaira indica) is commonly caught as frozen by-catch from Indonesian tuna longline fleets. Its contribution estimated 18% (~2,500 tons) from total catch in Indian Ocean. Relative abundance indices as calculated based on commercial catches are the input data for several to run stock assessment analyses that provide models to gather information useful information for decision making and fishery management, however, little are known about the influence of environmental factors to its abundance. In this paper, the abundance was represented as standardized index in order to eliminate any bias on other factors which might influence it. Data were collected from August 2005 to December 2017 through scientific observer program (2005-2017) and national observer program (2016-2017). Most of the vessels monitored were based in Benoa Port, Bali. Overall, time trends of abundance was fluctuated, although, there was increasing trend since 2010 then dropped significantly into relatively similar figure in 2005. Even though, Sea Surface Temperature (SST) and Sea Surface Height (SSH) were statistically significant when incorporating into the models, but it allegedly wasn’t the main driver in determining the abundance of black marlin. Instead, it was more likely driven by spatio-temporal factors (year and area) effect rather than environmental changes.

scholarly journals Spatio-temporal distribution of eggs and larvae of half-fin anchovy Setipinna taty (Valenciennes, 1848) in the inshore waters off Jiangsu, China

2019 ◽  
Vol 66 (1) ◽  
Author(s):  
Yan Jin ◽  
Zun-Lei Liu ◽  
Jian-Hua Tang ◽  
Yong Liu
Keyword(s):  
Fishery Management ◽  
Life Stage ◽  
Temporal Distribution ◽  
Early Life Stage ◽  
Additive Models ◽  
Significant Shift ◽  
Larvae And Juveniles ◽  
Inshore Waters ◽  
Spatio Temporal ◽  
Eggs And Larvae

Understanding the spatial distribution and environmental characteristics of fish spawning grounds is essential to design effective fishery management. The half-fin anchovy Setipinna taty (Valenciennes, 1848) plays an important role in the marine food web. A survey with 54 stations was conducted in 2014 to study the spatio-temporal distribution of eggs and larvae of half-fin anchovy around the inshore waters of Jiangsu, China. Half-fin anchovy eggs, larvae and juveniles were collected every month from April to July 2014. Generalised additive models were used to investigate the relationship between distribution of eggs, larvae and juveniles and environmental variables. A total of 4150 eggs and 685 half-fin anchovy larvae and juveniles were caught during the survey. During the spawning season, the highest egg densities were located in the inshore water area (121°-122°E, 32.5-33.5°N), with no significant shift in location of egg densities through time. The distribution of larvae and juveniles mostly overlapped with the egg distribution, suggesting that the early life stage of half-fin anchovy are distributed within the inshore waters of Jiangsu. The optimal water temperature, salinity and depth for eggs and larvae were in the range of 14.0-24.6°C, 28.7-29.8 ‰ and 15.9-17.4 m, respectively.

scholarly journals Identifying the distribution of Atlantic cod spawning using multiple fixed and glider-mounted acoustic technologies

2019 ◽  
Vol 76 (6) ◽  
pp. 1610-1625 ◽  
Author(s):  
Douglas R Zemeckis ◽  
Micah J Dean ◽  
Annamaria I DeAngelis ◽  
Sofie M Van Parijs ◽  
William S Hoffman ◽  
...  
Keyword(s):  
Gadus Morhua ◽  
Fishery Management ◽  
Gulf Of Maine ◽  
Atlantic Cod ◽  
Temporal Distribution ◽  
Management Actions ◽  
Spawning Site ◽  
Management Measures ◽  
Fish Spawning ◽  
Spatio Temporal

Abstract Effective fishery management measures to protect fish spawning aggregations require reliable information on the spatio-temporal distribution of spawning. Spawning closures have been part of a suite of fishery management actions to rebuild the Gulf of Maine stock of Atlantic cod (Gadus morhua), but difficulties remain with managing rebuilding. The objective of this study was to identify the spatial and temporal distribution of cod spawning during winter in Massachusetts Bay to improve our understanding of cod spawning dynamics and inform fisheries management. Spawning was investigated in collaboration with commercial fishermen during three winter spawning seasons (October 2013–March 2016) using acoustic telemetry and passive acoustic monitoring equipment deployed in fixed-station arrays and mounted on mobile autonomous gliders. Tagged cod exhibited spawning site fidelity and spawning primarily occurred from early November through January with a mid-December peak and some inter-annual variability. The spatial distribution of spawning was generally consistent among years with multiple hotspots in areas >50 m depth. Current closures encompass most of spawning, but important areas are recommended for potential modifications. Utilizing multiple complementary technologies and deployment strategies in collaboration with commercial fishermen enabled a comprehensive description of spawning and provides a valuable model for future studies.

Fecundity and Gonado-somatic Index of Trichiurus lepturus (Linnaeus, 1758) Along the Zamboanga del Norte Coast

2018 ◽  
Vol 6 (7) ◽  
pp. 120
Author(s):  
Ma. Dulce C. Guillena
Keyword(s):  
Sex Ratio ◽  
Stock Assessment ◽  
Chi Square ◽  
Moon Phases ◽  
Ovary Weight ◽  
Moment Coefficient ◽  
Trichiurus Lepturus ◽  
Significant Difference ◽  
The Relationship ◽  
Somatic Index

Gonado-somatic index and fecundity are tools for measuring the sexual maturity and ability of animals to reproduce.  This study investigates the reproduction of Trichiurus lepturus. Specifically, this aimed to determine the sex ratio, the GSI, the relationship between fecundity and total length, fecundity and total weight, fecundity and ovary weight. The Descriptive Method of research was used.  Percentage and chi-square was utilized in determining the percentage of occurrence and sex ratio respectively.   Pearson r Product Moment Coefficient of Correlation was used to determine the relationships of the parameters. The study revealed that females outnumbered males and the sex ratio for different month showed significant difference.  Spawning season was observed to occur in November and December as revealed in its GSI values and it synchronized with the full and new moon phases.  Fecundity is positively correlated with body weight, body size, and ovary weight where ovary weight is observed to be the best index for fecundity.  The results of this study could be used further for formal stock assessment of cutlassfish fishery.

Influence of Planting Density on Root Spatio-Temporal Distribution of Different Types of Maize under High-Yielding Cultivation Conditions

2013 ◽  
Vol 38 (7) ◽  
pp. 1286-1294 ◽  
Author(s):  
Zong-Xin LI ◽  
Yuan-Quan CHEN ◽  
Qing-Cheng WANG ◽  
Kai-Chang LIU ◽  
Wang-Sheng GAO ◽  
...  
Keyword(s):  
Temporal Distribution ◽  
Planting Density ◽  
Cultivation Conditions ◽  
Different Types ◽  
Spatio Temporal
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