Ecosystem-based fishery management (EBFM) is a new direction for fishery management, essentially reversing the order of management priorities to start with the ecosystem rather than the target species. This concept of management is a direct extension of the concept of a holistic approach incorporating interspecific interactions and physical environmental influences. However, because of the limited understanding of the complexity of marine ecosystems, few fisheries are actually managed on a multispecies basis. Even now, in order to specify a practical fishing policy we need a single-species model and utilize it by partially taking account of the effects of other factors mentioned above on the target species biomass. In fact, it is contended that in systems with moderate amounts of data, EBFM could be characterized by effective single-species management with the addition of precautionary set-asides for unknown ecosystem components. Hence, it is still necessary to examine a single-species model so as to clarify the extent of its applicability. The model investigated in this paper is what is called the dynamic pool model, which was proposed by C.W. Clark in the mid-1970s as a dynamic optimization of the classic Beverton and Holt static model for a fishery, in an attempt to make the process of growth and aging inherent in each of the creature resources reflect directly into the economic process. This dynamic model has been applied to a wide variety of commercial fish species. However, the applications have been largely confined to computer simulations using the discrete-time stand-by of the original Clark continuous-time model. This situation is caused mainly by the complexity of the mathematical structure of the Clark model. In this paper, we first specify the material related to the complexity. Subsequently, we provide a rigorous proof for the long-standing conjecture due to Clark concerning the optimal path or harvesting schedule. In addition, two derivative cases are examined: one is the case in which a year-class of fish leaves a given fishing sea area permanently before its natural biomass peaks, the other is the case in which the escapement of a year-class is required to be more than a given minimum level.
Reviews in Fish Biology and Fisheries – Springer Journals
Published: Jul 14, 2007
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.
Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.
All the latest content is available, no embargo periods.
“Hi guys, I cannot tell you how much I love this resource. Incredible. I really believe you've hit the nail on the head with this site in regards to solving the research-purchase issue.”Daniel C.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud
“I must say, @deepdyve is a fabulous solution to the independent researcher's problem of #access to #information.”@deepthiw
“My last article couldn't be possible without the platform @deepdyve that makes journal papers cheaper.”@JoseServera