1 / 24

Fishery Biology

Fishery Biology. Fisheries Management. Provide people with a sustained, high, and ever-increasing benefit from their use of aquatic resources Problems - late-1800s - industrial revolution Improved access to fish Improved effectiveness of fishing equipment

carsten
Télécharger la présentation

Fishery Biology

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Fishery Biology

  2. Fisheries Management • Provide people with a sustained, high, and ever-increasing benefit from their use of aquatic resources • Problems - late-1800s - industrial revolution • Improved access to fish • Improved effectiveness of fishing equipment • Improved processing and distribution of fish

  3. Problems resulted in: • Overexploitation (overfishing) in many areas • Catch exceeded maximum sustainable yield • Environmental degradation • Populations exhibit decline • Some commercial species driven to or near extinction

  4. Dealing with the problem • Fish culture • Fish rescue • Fishing regulations • A progressive movement

  5. Fish populations served: • Primary purpose - provide food • Secondary purpose - provide economic value • “crops” to be planted, managed, harvested Maximum sustainable yield (MSY) - efficiency

  6. Additions Growth Recruitment immigration Losses Natural mortality Fishing mortality emigration Fish population abundance changes:

  7. Population Dynamics • Led to conclusion that greatest long-term yield of fish achieved by allowing small fish to grow before harvesting them • But no scientific proof!

  8. Ecology and Fisheries • Ecology as a science provided hypotheses, principles, and fisheries provided natural laboratories for testing them

  9. Early Focus of Fisheries Science • Describe, survey fish, etc., in important waters • Determine physicochemical characteristics • Gather fish life history, ecology information

  10. New Data • Confirmed that habitat destruction, overfishing had negative impacts on fish populations • Led to growth of fisheries management, development of most techniques still used today

  11. Recreational Fishing Growth • Demands for regulations on competing commercial harvests • Eliminate markets for commercially caught freshwater predatory fish

  12. Regulation of Recreational Fishing • First highly restrictive, uniformly implemented • Closed seasons, minimum size, equipment restrictions, creel limits (daily catch) • Next changed to uniformly liberal regulations • Now back to stricter regulations

  13. Primary Funding for Inland Fishery Management in U.S. • Federal Aid in Sport Fish Restoration Act (1950) • Dingell-Johnson (D-J) Act • 10% excise tax on specified fishing equipment

  14. Primary Funding for Inland Fishery Management in U.S. • Wallop-Breaux Act (1985) • Expanded range of items taxed (e.g., boat fuel) • Extended funding to marine recreational fisheries • Doubled previous level of funding ($332 million in 1992)

  15. Different Fish Problems in Different U.S. Regions • Pacific NW - Pacific salmon - reduced runs • Reduced future generations

  16. Different Fish Problems in Different U.S. Regions • SE - raising fish in farm ponds • Predator, prey balance for best fishing

  17. Different Fish Problems in Different U.S. Regions • Midwest, Mideast - techniques for removal, control of unwanted fishes • Commercial netting • Chemical fish poisons

  18. Fish Stocking Changes • Initially widespread, promiscuous introductions of fish eggs, larvae • Now more selective stocking, where growth and survival are probable • Raised in hatcheries to larger size for better survival • “put-and-take” stocking of catchable-size fish

  19. Habitat Modifications • Habitat-related limits to fish size, abundance • Improve habitat to remove limits • Add artificial structures to lakes, streams • Build artificial lakes • Farm ponds • Reservoirs

  20. MSY focus changing during last half-century • More than simply maximizing physical yield • Additional concerns • Economic - e.g., aesthetic values • Sociological - e.g., limited access to fishery • Ecological - e.g., multi-species management

  21. Optimum Sustainable Yield • Includes broad range of concerns • Unique management goal for each fishery • More realistic • Recognizes existence of ecosystem, human need diversities • Greatly complicates management

  22. Important additional roles of fisheries management • Habitat management • Instream flow studies • Watershed land use - mitigation • Habitat rehabilitation - streams, wetlands

  23. Important additional roles of fisheries management • Organism management • Single-species vs. multi-species management • Endangered, rare species management • Management of non-harvested species • Prey • Competitors • Aquaculture

  24. Important additional roles of fisheries management • People management • Methods for assessing user demands, values

More Related