Fish stocks
Fish stocks are subpopulations of a particular species of fish, for which intrinsic parameters (growth, recruitment, mortality and fishing mortality) are traditionally regarded as the significant factors determining the stock's population dynamics, while extrinsic factors (immigration and emigration) are traditionally ignored.
Concepts
The stock concept
All species have geographic limits to their distribution, which are determined by their
For fish, it is rare for an individual to reproduce randomly with all other individuals of that species within its biological range. There is a tendency to form a structured series of discrete populations which have a degree of reproductive isolation from each other in space, in time, or in both. This isolation is reflected in the development between sub-populations of
The currently accepted definition of a stock in fisheries science, is that of Begg et al. (1999), “…[a “stock”] describes characteristics of semi-discrete groups of fish with some definable attributes which are of interest to fishery managers.”
Stock identification is a field of fisheries science which aims to identify these subpopulations, based on a number of techniques.This concept is applied in sustainable development goal 14 where target 14.4 is measured a fish stock sustainability indicator 14.4.1.[1]
Straddling stock
The
Straddling stocks are usually
Straddling stock can be compared with
Assessment
In fisheries science and ecology, stock assessment is an important tool in fisheries management.
In particular, to ensure continued, healthy, fish stocks, measurements of the
The
Fluctuations
The stocks for individual marine species can "boom and bust" in linked and compensatory ways. For example, in billfish longline fisheries, the Atlantic catch of blue marlin declined in the 1960s. This was accompanied by an increase in sailfish catch. The sailfish catch then declined from the end of the 1970s to the end of the 1980s, compensated by an increase in swordfish catch. As a result, the overall billfish catch remained fairly stable. At Georges Bank, a decline in cod during the 1960s was accompanied by a rise in flatfish, and more recently, with the collapse of the predatory Atlantic cod, lobster catches in Maine have boomed.[8]
See also
- List of harvested aquatic animals by weight
- Overfishing
References
- ^ "sustainable development goals".
- ^ Straddling stocks Archived 2015-06-03 at the Wayback Machine
- ^ Pelagic and straddling stocks
- ] Rome, Fisheries Report No. 829.
- ^ International Council for the Exploration of the Sea (ICES) website Archived 2011-06-12 at the Wayback Machine
- ^ Living Blue Planet Report wwf.org.au September 2015 Archived 2015-09-26 at the Wayback Machine
- ^ "Goal 14 targets". UNDP. Archived from the original on 2020-09-30. Retrieved 2020-09-24.
- ^ Duffy, J. Emmett (2008) Marine biodiversity and food security Encyclopedia of Earth. Updated 25 July 2008.
Further reading
- Begg GA, Friedland KD and Pearce JB (1999) "Stock identification and its role in stock assessment and fisheries management: an overview." Fisheries Research, 43:1–8.
- Booke HE (1999) "The stock concept revisited: perspectives on its history in fisheries" Fisheries Research, 43 (1–3): 9–11.
- Cadrin SX, Friedland KD and Waldman JR (2004) Stock Identification Methods : Applications in Fishery Science. ISBN 0-12-154351-X
- Pintassilgo, P and Lindroos, M "Management of Straddling Fish Stocks: A Bioeconomic Approach" In: Encyclopedia of Life Support Systems – Volume 5, UNESCO.
External links
- Identification of stocks of horse macekerel, Trachurus trachurus
- Identification of stocks of herring, Clupea harengus
- FAO Fisheries Department Archived 2008-07-06 at the Wayback Machine and its SOFIA report Archived 2010-06-10 at the Wayback Machine addressing fish stocks