scholarly journals Gompertzian law of growth for reserved area fishery model with non-selective harvesting in unreserved area

1997 ◽  
Vol 94 (2-3) ◽  
pp. 243-253 ◽  
Author(s):  
A. Mukhopadhyay ◽  
J. Chattopadhyay ◽  
P.K. Tapaswi

2006 ◽  
Vol 14 (01) ◽  
pp. 91-99 ◽  
Author(s):  
YONGZHEN PEI ◽  
LANSUN CHEN ◽  
CHANGGUO LI ◽  
CHUNHUA WANG

In this work, we consider a logistic fishery model and discuss the selective impulsive harvesting of fish above a certain age or size by incorporating a time delay in the impulsive harvesting term. It is proved that there exists an asymptotically stable positive periodic solution [Formula: see text] when the catchability coefficient h is less than some critical value [Formula: see text]. It is concluded that [Formula: see text] and [Formula: see text] are increasing with respect to l. Simulations shows that the delayed harvesting is advantageous to the sustainability of the population.


Author(s):  
Gert Kootstra ◽  
Xin Wang ◽  
Pieter M. Blok ◽  
Jochen Hemming ◽  
Eldert van Henten

Abstract Purpose of Review The world-wide demand for agricultural products is rapidly growing. However, despite the growing population, labor shortage becomes a limiting factor for agricultural production. Further automation of agriculture is an important solution to tackle these challenges. Recent Findings Selective harvesting of high-value crops, such as apples, tomatoes, and broccoli, is currently mainly performed by humans, rendering it one of the most labor-intensive and expensive agricultural tasks. This explains the large interest in the development of selective harvesting robots. Selective harvesting, however, is a challenging task for a robot, due to the high levels of variation and incomplete information, as well as safety. Summary This review paper provides an overview of the state of the art in selective harvesting robotics in three different production systems; greenhouse, orchard, and open field. The limitations of current systems are discussed, and future research directions are proposed.


2021 ◽  
Vol 11 (12) ◽  
pp. 2003581
Author(s):  
Chenchen Yang ◽  
Wei Sheng ◽  
Mehdi Moemeni ◽  
Matthew Bates ◽  
Christopher K. Herrera ◽  
...  

2005 ◽  
Vol 62 (3) ◽  
pp. 483-492 ◽  
Author(s):  
Silvio Simonit ◽  
Charles Perrings

Abstract We consider the potential for using prices as leading indicators of changes in stocks and yields in the freshwater capture fishery in Lake Victoria. Fertilizer run-off from agricultural land is a major cause of nutrient loading, along with soil erosion, atmospheric deposition, and point pollution from industrial and domestic affluent. The interactions between fertilizer applications, water quality, fish stocks, and yields are modelled in order to predict the effect of changes in the price of fertilizers on the fishery. The fishery model includes a measure of Chl a concentration (a proxy for phytoplankton density). The consequences of changes in Chl a concentration for fish stocks are modelled using Ecopath. We show that fertilizer prices are effective leading indicators of changes in fish biomass and yield.


2021 ◽  
pp. 157-164
Author(s):  
D. Sarri ◽  
S. Priori ◽  
R. Lisci ◽  
S. Lombardo ◽  
L. D’Avino ◽  
...  

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