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|data||files||public||Summary of prey groups found in harbor seal scat samples from the San Juan Islands analyzed |
at the Acevedo lab at Western Washington University during 2005-2008 (Seal_response_to_prey
|Row Type||Variable Name||Attribute Name||Data Type||Value|
|attribute||NC_GLOBAL||acquisition_description||String||From Lance et al.:
From 2005 to 2008, fecal samples (scats) were collected seasonally over 3
collection periods: March to early June (\u2018spring\u2019), late July to
September (\u2018summer/fall\u2019), and January to February
(\u2018winter\u2019). Scats were collected from 23 haul-out locations during
daytime low tides. The sites were dispersed throughout the study area,
represented various habitat types used by harbor seals, were the largest haul-
outs where adequate sample sizes could be collected, and were easily
accessible by boat. Two or three collection trips were made each season, with
a target sample size of 60 scats per season per region.
Samples were stored frozen. In the lab, samples were enclosed in fine mesh
paint-strainer bags and cleaned using a washing machine or nested sieves. Hard
parts were cleaned and stored dry. Prey were identified to lowest possible
taxon using a dissecting microscope, reference fish bone collections, and
published keys. Fish species from fecal samples were placed into 11 non-
overlapping prey groups based on taxonomy. Taxonomic resolution (species vs.
family or genus) was based on resolution of the prey remains. The category
\u2018other\u2019 included for all remaining prey species with unweighted
occurrence frequencies <5%. Rockfish were included as a prey group despite an
overall low occurrence frequency because of conservation interest and the
objectives of the present study. To gain insights into seasonal diet
variation, the frequencies were weighted by the numbers of seals present in
each region in the spring and summer/fall
|attribute||NC_GLOBAL||awards_0_funder_name||String||NSF Division of Ocean Sciences|
|attribute||NC_GLOBAL||awards_0_program_manager||String||David L. Garrison|
|attribute||NC_GLOBAL||comment||String||Summary of prey found in seal scat from the San Juan Islands
Lead PI: Alejandro Acevedo-Gutierrez
Version: 12 Dec 2012
|attribute||NC_GLOBAL||Conventions||String||COARDS, CF-1.6, ACDD-1.3|
|attribute||NC_GLOBAL||creator_email||String||info at bco-dmo.org|
|attribute||NC_GLOBAL||data_source||String||extract_data_as_tsv version 2.3 19 Dec 2019|
|attribute||NC_GLOBAL||keywords||String||bco, bco-dmo, biological, chemical, data, dataset, dmo, erddap, freq, freq_of_occurrence, management, occurrence, oceanography, office, preliminary, region, season, taxon|
|attribute||NC_GLOBAL||people_0_affiliation||String||Western Washington University|
|attribute||NC_GLOBAL||people_0_role||String||Lead Principal Investigator|
|attribute||NC_GLOBAL||people_1_affiliation||String||United States Geological Survey|
|attribute||NC_GLOBAL||people_1_person_name||String||Jeffrey F Bromaghin|
|attribute||NC_GLOBAL||people_2_affiliation||String||Washington Department of Fish and Wildlife|
|attribute||NC_GLOBAL||people_2_person_name||String||Steven J Jeffries|
|attribute||NC_GLOBAL||people_3_affiliation||String||University of Alaska, Anchorage|
|attribute||NC_GLOBAL||people_3_person_name||String||John M Kennish|
|attribute||NC_GLOBAL||people_4_affiliation||String||Washington Department of Fish and Wildlife|
|attribute||NC_GLOBAL||people_4_person_name||String||Monique M Lance|
|attribute||NC_GLOBAL||people_5_affiliation||String||National Marine Fisheries Service|
|attribute||NC_GLOBAL||people_5_person_name||String||Philip S Levin|
|attribute||NC_GLOBAL||people_6_affiliation||String||Woods Hole Oceanographic Institution|
|attribute||NC_GLOBAL||people_6_role||String||BCO-DMO Data Manager|
|attribute||NC_GLOBAL||projects_0_description||String||From NSF proposal:
This project is a collaborative study of the responses of harbor seals and other mammalian predators to changes in prey density in Puget Sound. The general study approach will involve multi-year field estimates to observe the responses of predators to rockfish density in protected areas, candidate marine reserves, and unprotected sites.
The collaborating investigators will estimate 1) rockfish density using visual and mark and recapture techniques; 2) predator abundance using aerials surveys and dedicated land observations; and 3) predator food consumption using scat to describe diet, tagging of harbor seals to describe individual foraging sites, and population-based and individual bioenergetics models to describe consumption of rockfish. The investigators will also take into account confounding factors that might explain predator behavior, such as environmental variables and alternative prey, by creating a GIS database from available information from the area. The different field observations and database estimates are explicitly linked through a common hypothesis and coordinated methodologies, and their results will be integrated into a model describing the impact of predation on rockfish populations. The responses of top predators to changes in prey density and their impact on fish populations of interest are unknown. This study will evaluate the effectiveness of MPAs as fish refugia, offer a framework for the management and conservation of marine resources, and provide an exciting opportunity for students to participate in ecological and conservation research.
1) Harbor seals and other pinniped species show aggregative responses to changes in prey density. Hence, their abundance will increase with fish density.
2) Harbor seals and other pinniped species show Type 2 or 3 functional responses to changes in prey density. Thus, their consumption rate of a particular prey type follows an asymptotic or sigmoidal curve relative to the prey’s density, respectively.
3) Predation by harbor seals and other pinniped species is sufficiently intense that it impedes recovery of depleted fish populations.
1) Quantify the number of harbor seals and other pinniped species in relation to rockfish density and other environmental (confounding) factors.
2) Estimate the consumption rate of harbor seals and other pinniped species in relation to rockfish density and other prey species.
3) Correlatively estimate the influence of predation by harbor seals and other pinniped species on survivorship and population size of rockfish.
Publications resulting from this NSF award:Bjorland, R. H., Pearson, S. F, Jeffries, S. J, Lance, M. M., Acevedo- Gutiérrez, A. & Ward, E. J. 2015. Stable isotope mixing models elucidate sex and size effects on the diet of a generalist marine predator. Marine Ecology Progress Series 526: 213-225. DOI: 10.3354/meps11230Bromaghin, J. F., Lance, M. M., Elliott, E. W., Jeffries, S. J., Acevedo-Gutierrez, A. & Kennish, J. M. 2013. New insights into the diets of harbor seals in the Salish Sea of western North America revealed by quantitative fatty acid signature analysis. Fishery Bulletin 111: 13-26. DOI: 10.7755/FB.111.1.2Buzzell, B.1, Lance, M. & Acevedo-Gutiérrez, A. 2014. Spatial and temporal variation in river otter (Lontra canadensis) diet and predation on rockfish (Genus Sebastes) in the San Juan Islands, Washington. Aquatic Mammals 40: 150- 161. DOI: 10.1578/AM.40.2.2014.150Howard, S., Lance, M., Jeffries, S. & Acevedo-Gutierrez, A. 2013. Fish consumption by harbor seals (Phoca vitulina) in the San Juan Islands, WA. Fishery Bulletin 111: 27-41. DOI: 10.7755/FB.111.1.3Lance, M. M., Chang, W.-Y., Jeffries, S. J., Pearson, S. F. & Acevedo-Gutierrez, A. 2012. Harbor seal diet in northern Puget Sound: implications for the recovery of depressed fish stocks. Marine Ecology Progress Series 464:257-271. DOI:10.3354/meps09880Luxa, K. & Acevedo-Gutierrez, A. 2013. Food habits of harbor seals (Phoca vitulina) in two estuaries in the central Salish Sea. Aquatic Mammals 39: 10- 22. DOI: 10.1578/AM.39.1.2013.10Peterson, S., Lance, M. M., Jeffries, S. J. & Acevedo-Gutierrez, A. 2012. Long distance movements and disjunct spatial use of harbor seals (Phoca vitulina) in the inland waters of the Pacific Northwest. PLoS ONE 7: e39046. DOI: 10.1371/journal.pone.0039046Thomas, AC; Lance, MM; Jeffries, SJ; Miner, BG; Acevedo-Gutierrez, A. 2011. Harbor seal foraging response to a seasonal resource pulse, spawning Pacific herring. Marine Ecology-Progress Series, v.441. p. 225. DOI: 10.3354/meps09370Ward, EJ; Levin, PS; Lance, MM; Jeffries, SJ; Acevedo-Gutierrez, A. 2012. Integrating diet and movement data to identify hot spots of predation risk and areas of conservation concern for endangered species. Conservation Letters, v.5, p. 37. DOI: 10.1111/j.1755-263X.2011.00210.xWilson, K.2, Lance, M., Jeffries, S. & Acevedo-Gutiérrez, A. 2014. Fine-scale variability in harbor seal foraging behavior. PLoS ONE 9: e92838. DOI: 10.1371/journal.pone.0092838.
|attribute||NC_GLOBAL||projects_0_geolocation||String||Salish Sea, USA and Canada|
|attribute||NC_GLOBAL||projects_0_name||String||Responses of Seals and Sea Lions to Increased Rockfish Density|
|attribute||NC_GLOBAL||publisher_name||String||Biological and Chemical Oceanographic Data Management Office (BCO-DMO)|
|attribute||NC_GLOBAL||standard_name_vocabulary||String||CF Standard Name Table v55|
|attribute||NC_GLOBAL||summary||String||Frequency of occurrence of taxonomic groups of prey identified in harbor seal scat samples collected from 2005 to 2008, summarized by region and season. Four regions of the San Juan Islands of Washington state were sampled: Eastern Bays, Rosario Strait, San Juan Channel, and the Southern Strait of Georgia.|
|attribute||NC_GLOBAL||title||String||Summary of prey groups found in harbor seal scat samples from the San Juan Islands analyzed at the Acevedo lab at Western Washington University during 2005-2008 (Seal_response_to_prey project)|
|attribute||taxon||description||String||Name of the prey group.|
|attribute||region||description||String||Name of the geographical sampling region.|
Spring = March to early June,
Summer/Fall = late July to September,
Winter = January to February.
|attribute||freq_of_occurrence||description||String||Frequency of occurrence (FO). Proportion of the number of occurrences of the fish species out of the total number of scat samples.|
|attribute||freq_of_occurrence||long_name||String||Freq Of Occurrence|
The information in the table above is also available in other file formats (.csv, .htmlTable, .itx, .json, .jsonlCSV1, .jsonlCSV, .jsonlKVP, .mat, .nc, .nccsv, .tsv, .xhtml) via a RESTful web service.