“The Impact of Pinnipeds on the Anadramous Fish Populations and Recreational Fishery of the Sacramento Delta”
A Thesis Proposal by
W. Mark Dendy
One to five sentences stating the goal of the research project.
Something to the effect of ... To assess the distribution and abundancy of pinnipeds in the Sacramento and San Joaquin Rivers during migration of fall and winter runs of anadramous fish populations.
A one-half page statement as to the potential ecological or scientific impact of this project (i.e., the nature of the contribution and the fields affected).
Succinctly review current literature relevent to the proposal.
(This is my attempt so far, but I am under a real time constraint now!)
For decades, there has been competition between marine mammals and commercial fisheries worldwide.1,2 Anadramous fishes found in the Sacramento Delta are part of commercial and recreational fisheries from the coastal regions to the breeding habitats
far inland. The California Sea Lion (Zalophus californianus) and Pacific Harbor Seal (Phoco vitulina) are known to prey on salmonids in the ocean and bays.3 The population of California Sea Lions in the U.S. was estimated at 237,000 for 2006 and is increasing at an annual rate of 5.4 – 6.1%.4 With the population of these opportunist feeding marine mammals growing at such a rapid rate, competition with fisheries has increased.
The anadramous fish populations which migrate inland throughout the Sacramento Delta have declined dramatically in the past 50 years, due to a combination of factors including habitat destruction
and overfishing.5,6 These include the Winter Run Chinook Salmon (Oncorhynchus tshawytscha) listed as Federal and State Endangered Species, Spring Run Chinook Salmon (Oncorhynchus tshawytscha), listed as Federal and State Threatened,7,8 Steelhead (Oncorhynchus mykiss), Federal Threatened,8 Striped Bass, White Sturgeon (Acipenser transmontanus) and Green Sturgeon (Acipenser medirostris). California Sea Lions and Pacific Harbor Seals have been protected by the federal Marine Mammal Protection Act since 1972.9 Although some marine mammals, the Hawaiian Monk Seal and the Stellar Sea Lion remain endangered,10 the California Sea Lion and Harbor Seal have experienced a population explosion resulting in increased competition for foraging. Consequently these pinnipeds need to increase foraging ranges as a means of survival. As foraging ranges increase, energy demands increase. The end result is increased consumption of available resources.
As Sea Lions and Harbor Seals move up into the river system where their natural predators, the killer whales and great white sharks11 are not present, they find themselves at the top of the food web. Therefore, their main competition for resources is humans, particularly recreational fishermen.
Recreational fishermen, some fisheries biologists, lawmakers, and other interest groups have proposed solutions included culling sea lions, hazing them,12 and most recently, in the states of Oregon and Washington, killing some individual “rogue” sea lions.13 Yet no study or model exists that establishes what impact California Sea Lions and Pacific Harbor Seals have on the declining anadramous fish populations and the recreational sport-fishery in the rivers and sloughs of the Sacramento Delta.
(Please note that fall and winter runs of anadramous fishes are after breeding season of pinnipeds has occurred and that primarily male seal lions and harbor seals have been noted preying on fish in the Delta river system.)
Outline of Proposal:
This should be one to two pages describing the strategy of the proposed experiments. Various possible results should be discussed and how they would be interpreted to achieve the specific aim.
Briefly discuss the methods to be used in the experiments, with adequate description so any reasonably competent scientist can understand. This section should usually refer principally to published procedures and can be quite short. If new methods must be developed or old methods must be modified, this section may have to be longer.
(To writer: Model observational study portion after
Wright BE, Riemer SD, Brown RF, Ougzin AM, Bucklin KA (2007) ASSESSMENT OF HARBOR SEAL PREDATION ON ADULT SALMONIDS IN A PACIFIC NORTHWEST ESTUARY. Ecological Applications: Vol. 17, No. 2 pp. 338–351
Predation by seals on salmonids in two Scottish estuaries By: Carter, T. J., Pierce, G. J., Hislop, J. R. G., Houseman, J. A., Boyle, P. R., Fisheries Management and Ecology, 0969997, June 1, 2001, Vol. 8, Issue 3
Model fishermen survey methods after
Harvey, J. and M.J. Weise. 1997. Impacts of California sea lions and Pacific harbor seals on salmonids in Monterey Bay, California)
Pertinent Info to include:
Area to be limited to Sacramento River from Rio Vista, CA to Colusa, CA and the San Joaquin River. Please give brief description of Sacramento Delta area and waters.
Conduct dockside interviews with recreational fishermen at public launch areas on the Sacramento and San Joaquin Rivers.
Distribute preaddressed and stamped voluntary interview forms to Sacramento Delta marinas for Harbormasters to hand out to fishermen that report encounters or observations of sea lions.
Conduct observational studies in areas of known sea lion predation and areas where reported haul-outs have occurred within the Sacramento Delta.
Proposed dates for data collection:
September 2007-January 2008
Literature cited. This must use the CBE (Council of Biology Editors) publication format. No page limitation. This section can also be used for footnotes if the student feels that some parts of the proposal require more extensive exploration than can be accommodated in the limitation of the previous sections.
Some of my references:
1. Northridge, S.P. An updated world review of interactions between marine mammals and fisheries. FAO Fisheries Technical Paper. No. 251, Suppl. 1. Rome, FAO. 1991. 58p.
2. DeMaster, Douglas P., Fowler, Charles W., Perry, Simona L. and Richlen, Michael F. Predation and Competition: The Impact of Fisheries on Marine-Mammal Populations over the Next One Hundred Years. Journal of Mammalogy, Vol. 82, No. 3 (Aug., 2001), pp. 641-651.
3. National Marine Fisheries Service (NMFS). 1997. Investigation of Scientific Information on the Impacts of California Sea Lions and Pacific Harbor Seals on Salmonids and on the Coastal Ecosystems of Washington, Oregon, and California. U.S. Dep. Commer., NOAA Tech. Memo. NMFS-NWFSC-28, 172 p.
4. Carretta, James V., Forney, Karin A., Muto, Marcia M., Barlow, Jay, Baker, Jaon, Hanson, Brad, and Lowry, Mark S. US Pacific marine mammal stock assessments: 2006. U.S. Dept. Commerce., NOAA Tech. Memo NOAA-TM-NMFS-SWFSC-398, (January 2007) 312 p.
Here are some questions that cannot be answered by this study, but could perhaps be looked at in future research? I am not sure if or how they should be incorporated into the research proposal.
Have fishery catches changed the composition of the fish community causing increased competition for prey with sea lions and harbor seals resulting in increased foraging ranges?
Have removals of prey by fisheries reduced ecosystem-wide prey abundance or availability resulting in increased foraging ranges of sea lions and harbor seals?
Have environmental changes altered the composition of the fish community, reducing the abundance, availability, or quality of prey resulting in increased foraging ranges of sea lions and harbor seals?
Have rapidly growing populations of pinnipeds altered the composition of the sea lion community, reducing the abundance, availability, or quality of prey for sea lions resulting in increased foraging ranges?
[ Order Custom Essay ]
[ View Full Essay ]
1. Northridge, S.P. An updated world review of interactions between marine mammals and fisheries. FAO Fisheries Technical Paper. No. 251, Suppl. 1. Rome,
FAO. 1991. 58p.
2. DeMaster, Douglas P., Fowler, Charles W., Perry, Simona L. And Richlen,
Michael F. Predation and Competition: The Impact of Fisheries on Marine-Mammal
Populations over the Next One Hundred Years. Journal of Mammalogy, Vol. 82, No.
(Aug., 2001), pp. 641-651.
3. National Marine Fisheries Service (NMFS). 1997. Investigation of Scientific
Information on the Impacts of California Sea Lions and Pacific Harbor Seals on Salmonids and on the Coastal Ecosystems of Washington, Oregon, and California.
U.S. Dep. Commer., NOAA Tech. Memo. NMFS-NWFSC-28, 172
4. Carretta, James V., Forney, Karin a., Muto, Marcia M., Barlow, Jay, Baker,
Jaon, Hanson, Brad, and Lowry, Mark S.U.S. Pacific marine mammal stock assessments: 2006. U.S. Dept. Commerce., NOAA Tech. Memo NOAA-TM-NMFS-SWFSC-398, (January 2007) 312
5. Draft EIR for the Chevron U.S.A. Long Wharf Marine Oil Terminal (February 27, 2006), section 4. www.slc.ca.gov/Division_pages/DEPM/DEPM_Programs_and_Reports/Chevron%20Long%20Wharf/Word/11%20Sec%204.3.doc.
6. California Marine Life Protection Act InitiativeRegional Profile of the North Central Coast Study Region (May 7, 2007), http://www.dfg.ca.gov/mrd/mlpa/pdfs/nccrp/profile.pdf.
7. Airame, S., S. Gaines, and C. Caldow. 2003. Ecological Linkages: Marine and estuarine ecosystems of central and northern California. NOAA, National Ocean Service. Silver Spring, MD. (available at (http://biogeo.nos.noaa.gov/products/canms_cd/data/pdfs/ELR.pdf).
8. CDFG, 2001. California's Living Marine Resources: A Status Report (ANR Publication #SG01-11) California Department of Fish and Game, http://anrcatalog.ucdavis.edu.
9. Ficke, Ashley a., Myrick, Christopher a. The Potential Effects of Anthropogenic Climate Change on Freshwater Fisheries (August 2004). Department of Fishery & Wildlife Biology, Colorado State University.
10. Sacramento Valley Workshop, California Legacy Project: Spotlight on Conservation (April 8-9, 2003), Workshop in Chico, http://www.legacy.ca.gov/pub_docs//Sac_Valley_Wkshp_interim_report.pdf.
14. Placer Legacy Open Space and Agricultural Conservation Program Implementation Report (June 2000). http://www.placer.ca.gov/Departments/CommunityDevelopment/Planning/PlacerLegacy/~/media/cdr/planning/PlacerLegacy/PlanChapters/plegacy_CHAPTERIV%20pdf.ashx.
15. Integrated Regional Water Management Plan Volume 1 (June 30, 2005). http://www.countyofplumas.com/publicworks/watershed/IRWMP_063005.pdf.
16. Borthwick, Sandra M., Weber, E.D. Travel Time and Condition of Juvenile Chinook Salmon Passed Through Red Bluff Research Pumping Plant. Calfed Bay-Delta Program (October 3-5, 2000).
17. Wright BE, Riemer SD, Brown RF, Ougzin AM, Bucklin KA (2007) Assessment of Harbor Seal Predation on Adult Salmonids in a Pacific Northwest Estuary.
Ecological Applications: Vol. 17, No. 2 pp. 338-351.
18. Carter, T.J., Pierce, G.J., Hislop, J.R.G., Houseman, J.A., Boyle, P.R. Predation by seals on salmonids in two Scottish estuaries. Fisheries Management and Ecology, (June 1, 2001) Vol. 8, Issue 3.
19. Harvey, J. And M.J. Weise. 1997. Impacts of California sea lions and Pacific harbor seals on salmonids in Monterey Bay, California.
20. Sacramento-San Joaquin Delta Atlas (August 8, 1995). http://rubicon.water.ca.gov/delta_atlas.fdr/daindex.html.