| Contributors | Affiliation | Role |
|---|---|---|
| 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 |
In 2009, the diving behavior of harbor seals was monitored near Protection Island, in WA state. Data include the percent of time spent by individual seals at different depth ranges. The diving data are summarized into four 6-hour time periods per day.
Related publications:
Thomas, 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/meps09370
Thomas, A. 2010. The behavioral response of harbor seals to seasonal prey pulses of spawning Pacific herring. MSc thesis, Department of Biology, Western Washington University, Bellingham, WA. Available from Alejandro Acevedo's lab website.
Five harbor seals were captured and tagged on Protection Island during from 12 to 13 January 2009. A combined satellite-linked time-depth recorder (TDR) and Fastloc GPS receiver (Wildlife Computers, model MK10AF) was epoxied to each animal's pelage on the dorsal midline.
The TDR sensor was set to sample every 10 seconds and record only dives greater than 2 meters in depth or greater than 30 seconds in duration. The tags summarized the TDR diving data of each animal into four 6-hour time periods.
BCO-DMO made the following modifications to the dataset:
- Changed parameter names to conform to BCO-DMO conventions;
- Replaced blanks with 'nd';
- Separated original date/time column into separate date and time columns;
- Transposed columns to rows for each of the depth bins.
| File |
|---|
seal_dive_time_per_depth.csv (Comma Separated Values (.csv), 1.40 MB) MD5:801648bf965236fbe72d2af9366fa5a0 Primary data file for dataset ID 3807 |
| Parameter | Description | Units |
| seal_id | Unique seal identification. | unitless |
| pttno | PTT tag number. | unitless |
| inst | Name of the instrument. MK10 = Wildlife Computers MK10 TDR tag. | unitless |
| date | Date (local time). | mm/dd/yy |
| time | Local time, 24-hour clock. The tags summarized the diving data of each animal into four 6-hour time periods. | HHMM |
| lat | Latitude, in decimal degrees. Positive = North. | decimal degrees |
| lon | Longitude, in decimal degrees. Positive = East. | decimal degrees |
| num_bins | Number of bins (depth ranges) which the data falls in. | integer |
| total_pcnt_time | Sum of all pcnt_time_at_depth values (approx. 100). | integer |
| depth | Depth range, in meters. | meters |
| pcnt_time_at_depth | Proportionate amount of time the individual spent at the depth range during the 6-hour time period. | % |
| Dataset-specific Instrument Name | Wildlife Computers TDR |
| Generic Instrument Name | Wildlife Computers Time-Depth Tag (TDR) |
| Dataset-specific Description | A combined satellite-linked time-depth recorder (TDR) and Fastloc GPS receiver (Wildlife Computers, model MK10AF) was epoxied to each animal's pelage on the dorsal midline. |
| Generic Instrument Description | Time depth recorders (TDR's) manufactured by Wildlife Computers, Redmond WA) are designed for studies of seals, penguins, fish, and marine mammals. Standard TDR's are mounted externally on the animal's body, where they record temperature and depth. See more information from the manufacturer. |
| Website | |
| Platform | shoreside San_Juan_Islands |
| Start Date | 2007-04-04 |
| End Date | 2009-08-03 |
| Description | Locations of seal captures and tagging for the project 'Responses of Seals and Sea Lions to Increased Rockfish Density' (PI: Alejandro Acevedo-Gutiérrez)
In 2007 - 2008, seals were captured in Padilla Bay (approx. 48.5165, -122.5168), Bird/Belle Rocks (approx. 48.4860, -122.7602), and Protection Island (approx. 48.1278, -122.9306). In 2009, seals were captured on Protection Island .
References:
Thomas, 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/meps09370
Ward, 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.x |
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.
Hypotheses:
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.
Objectives:
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/meps11230
Bromaghin, 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.111.1.2
Buzzell, 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.40.2.2014.150
Howard, 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.111.1.3
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
Luxa, 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.39.1.2013.10
Peterson, 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.0039046
Thomas, 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/meps09370
Ward, 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.x
Wilson, 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.
| Funding Source | Award |
|---|---|
| NSF Division of Ocean Sciences (NSF OCE) |