In this paper, we propose a fishery model with a discontinuous on–off harvesting policy, based on a very simple and well known rule: stop fishing when the resource is too scarce, i.e. whenever fish biomass is lower than a given threshold. The dynamics of the one-dimensional continuous time model, represented by a discontinuous piecewise-smooth ordinary differential equation, converges to the Sc...

In traditional harvesting model a fishing effort E is defined by the fishing intensity and does not address the inverse effect of fish abundance on the fishing effort. In this paper, based on a canonical differential equation model, we developed a new fishing effort model which relies on the density effect of fish population. This study concludes that a control parameter β( the magnitude of the...

We highlighted gaps in nutritional data for wild game meat and wild caught fish that have a regulated harvesting season in New York State, and examined the possible role that wild game and fish play in current trends towards consumption of local, healthy meat sources. This project is part of larger study that examines family food decision-making, and explores possibilities for leveraging the lo...

Women’s involvement in fisheries is more significant than often assumed. according to current estimates from nine major fish producing countries, they comprise 46% of the labor force in smallscale capture fisheries-related activities, including preand post-harvesting work. Their current engagement is shaped by rapidly dwindling fisheries stocks on one hand, and the increased global demand for f...

Fisheries scientist David Conover, dean and director of the Marine Sciences Research Center at SUNY Stony Brook, is leading the most extensive laboratory study to date on the effects of size-selective harvesting in fish stocks. As described in Scientific American magazine, he and his team mimicked fishing by removing 90 percent of the largest fish from a lab population of Atlantic Siversides (M...

The present paper deals with the problem of combined harvesting of two competing fish species, each of which obeys the law of logistic growth and releases a substance toxic to the other. The dynamical behaviour of the exploited system is examined. The possibility of existence of a bionomic equilibrium is discussed. The optimal harvesting policy is studied from the view point of control theory. ...

A 3-trophic level prey-predator model investigated the underlying nonlinear dynamics governing long-term (1960 to 1999) changes in pelagic fish stocks in the Black Sea. The model first explored the steady state dynamics under various combinations of consumption, harvesting and mortality rate values, and identified the critical parameters and their ranges that control equilibrium characteristics...

The overwhelming majority of farmed fish produced throughout the world are killed with little or no consideration for their welfare. Fasting periods can be excessive, transport stressful and killing inhumane. At the time of writing, the salmon industry is the only sector in which consideration of the welfare of the fish at slaughter has resulted in significant improvements throughout most of th...

To visualize or address complex real world problems, eliciting and mapping of a mental model is reasonable approach but it is far from sufficient by itself. In this article we present a system dynamics model. The purpose of the model is to develop a sustainable model for fish population, growth, and harvesting. The model was run through several important tests to determine its sensitivity to ch...