|Acevedo-Gutierrez, Alejandro||Western Washington University (WWU)||Lead Principal Investigator|
|Bromaghin, Jeffrey F||United States Geological Survey (USGS)||Co-Principal Investigator|
|Jeffries, Steven J||Washington Department of Fish and Wildlife||Co-Principal Investigator|
|Kennish, John M||University of Alaska, Anchorage (UAA)||Co-Principal Investigator|
|Lance, Monique M||Washington Department of Fish and Wildlife||Co-Principal Investigator|
|Levin, Philip S||National Marine Fisheries Service (NMFS)||Co-Principal Investigator|
|Rauch, Shannon||Woods Hole Oceanographic Institution (WHOI BCO-DMO)||BCO-DMO Data Manager|
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.
Also see the related dataset, seal_prey_species_counts (https://www.bco-dmo.org/dataset/3817), where counts are provided for individual species by season (with no distinction between sampling regions).
Data and methods, including sample sizes, are described in:
Lance, 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/meps09880
From Lance et al.:
From 2005 to 2008, fecal samples (scats) were collected seasonally over 3 collection periods: March to early June (‘spring’), late July to September (‘summer/fall’), and January to February (‘winter’). 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 ‘other’ 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
BCO-DMO made the following modifications:
- Changed parameter names to conform with BCO-DMO convention.
- Replaced spaces with underscores.
|region||Name of the geographical sampling region.||text|
|taxon||Name of the prey group.||text|
|freq_of_occurrence||Frequency of occurrence (FO). Proportion of the number of occurrences of the fish species out of the total number of scat samples.||%|
|season||Sampling season: Spring = March to early June, Summer/Fall = late July to September, Winter = January to February.||text|
|Start Date|| |
|End Date|| |
Marine Behavior and Ecology Lab at Western Washington University, led by Alejandro Acevedo-Gutierrez, lead PI for the project "Responses of Seals and Sea Lions to Increased Rockfish Density" (NSF OCE-0550443). Address: Department of Biology Western Washington University 516 High St. Bellingham, WA 98225
This document is created by info v 4.1f 5 Oct 2018 from the content of the BCO-DMO metadata database. 2020-07-03 15:07:53