1.6. Overview
19
As will be the case in most the models in this book, the interaction between multiple species from different taxa is presented in Chapter 12. The
model investigates the dynamics of organisms from three different trophic
levels-algae (giant kelp), marine mammals (sea otters), and invertebrates
(sea urchinsj-s-that interact on the west coast of North America.
Fishing activity is a major threat to marine systems worldwide. The remaining chapters investigate various ways in which fishing can affect the
marine environment. The goal of the model in Chapter 13 is to show that
accurately modulated fishing intensity has positive effects upon the productivity and return times of Nile perch and their prey base. Unlike many
other freshwater lakes, the dynamics of the biological system and the associated human communities in the African Rift lakes are similar to saltwater
systems in important ways and are therefore included in this book. The
model indicates that as Nile perch alter their endemic prey community, productivity of the Nile perch fishery decreases and the prey base is slow to recover. Results suggest that, through proper management, endemic cichlid
stocks can be conserved without a loss to the Nile perch fishery.
Chapter 14 presents a multi-species model of groundfish. Though prone
to similar levels and types of exploitation, the relative sizes of their individual populations varies because of differences in biological characteristics
and species interaction. As a consequence of these differences , management methods such as restrictions on mesh size show different success for
the different species in maintaining their population sizes. The model of
this chapter explores some of these management methods, including meshsize regulations and marine protected areas .
Chapter 15 establishes a linkage between patterns in habitat-mediated
survivorship of early benthic-phase juvenile cod with spatial variations in
habitat complexity by simulating habitat change based on fishing activities.
The model provides a basis for the determination of the role of MPAs for
enhancing recruitment success . Density-dependent natural mortality is
specified as three alternative functional response curves to assess the influence of different predator foraging strategies on juvenile survivorship during the first 12 months of demersal existence.
Chapter 16 addresses social aspects of fisheries management, drawing on
literature from anthropology, sociology , and economics. Specifically, the
model explores how socially based incentive strategies and deterrents affect
the fate of common property marine resources. The strategies are illustrated
with case studies from reef fisheries in Indonesia, the practices of the Cree
Indians in North America, and the lobster fishery in Maine, USA. The model
demonstrates that shocks to important system parameters can destabilize
the behavioral rules in the society leading to higher extraction levels, and
hence to a decline in the fish stocks. The analysis demonstrates that external changes can result in communities destroying resources that had previously been carefully controlled with social norms .
Chapters 17 and 18 investigate-from very different perspectives-economic consequences of aquaculture. While chapter 17 explores the roles a
19
As will be the case in most the models in this book, the interaction between multiple species from different taxa is presented in Chapter 12. The
model investigates the dynamics of organisms from three different trophic
levels-algae (giant kelp), marine mammals (sea otters), and invertebrates
(sea urchinsj-s-that interact on the west coast of North America.
Fishing activity is a major threat to marine systems worldwide. The remaining chapters investigate various ways in which fishing can affect the
marine environment. The goal of the model in Chapter 13 is to show that
accurately modulated fishing intensity has positive effects upon the productivity and return times of Nile perch and their prey base. Unlike many
other freshwater lakes, the dynamics of the biological system and the associated human communities in the African Rift lakes are similar to saltwater
systems in important ways and are therefore included in this book. The
model indicates that as Nile perch alter their endemic prey community, productivity of the Nile perch fishery decreases and the prey base is slow to recover. Results suggest that, through proper management, endemic cichlid
stocks can be conserved without a loss to the Nile perch fishery.
Chapter 14 presents a multi-species model of groundfish. Though prone
to similar levels and types of exploitation, the relative sizes of their individual populations varies because of differences in biological characteristics
and species interaction. As a consequence of these differences , management methods such as restrictions on mesh size show different success for
the different species in maintaining their population sizes. The model of
this chapter explores some of these management methods, including meshsize regulations and marine protected areas .
Chapter 15 establishes a linkage between patterns in habitat-mediated
survivorship of early benthic-phase juvenile cod with spatial variations in
habitat complexity by simulating habitat change based on fishing activities.
The model provides a basis for the determination of the role of MPAs for
enhancing recruitment success . Density-dependent natural mortality is
specified as three alternative functional response curves to assess the influence of different predator foraging strategies on juvenile survivorship during the first 12 months of demersal existence.
Chapter 16 addresses social aspects of fisheries management, drawing on
literature from anthropology, sociology , and economics. Specifically, the
model explores how socially based incentive strategies and deterrents affect
the fate of common property marine resources. The strategies are illustrated
with case studies from reef fisheries in Indonesia, the practices of the Cree
Indians in North America, and the lobster fishery in Maine, USA. The model
demonstrates that shocks to important system parameters can destabilize
the behavioral rules in the society leading to higher extraction levels, and
hence to a decline in the fish stocks. The analysis demonstrates that external changes can result in communities destroying resources that had previously been carefully controlled with social norms .
Chapters 17 and 18 investigate-from very different perspectives-economic consequences of aquaculture. While chapter 17 explores the roles a