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Monk Seal Ecosystem Model Data: A Comparison of Ecosystem Structure and Energy Flows of Monk Seal Populations from Laysan Island and French Frigate Shoals in the Northwestern Hawaiian Islands from 1998 through 2015 (NCEI Accession 0190881)

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To understand various ecosystem dynamics that could explain observed changes and differences in monk seal biomass at French Frigate Shoals (FFS) and Laysan (LAY), Ecopath with Ecosim (EwE) version 6.4.4 modeling software was used to conduct two types of simulations, sensitivity (to understand the system) and hindcast (to evaluate drivers of monk seal population dynamics). EwE models for LAY and FFS were developed and model output was compared between the 2 models. The model output data included in the data sets represent the most important conclusions as reported in the publication from this study. These are (1) the mean of the last 5 years of each perturbation for sensitivity assessment; and (2) hindcast simulations. The first data set was used to understand the main drivers of the trophic structure and energy flow in the ecosystems. Four perturbation scenarios were simulated for a time span of 40 years (2010 through 2049): (a) baseline (compare static structural ecosystem composition between FFS and LAY), (b) altered predator abundance (30% decrease in biomass of main predators in the ecosystem), (c) altered monk seal prey abundance (30% decrease in biomass of main monk seal prey groups, with and without bottomfish to test how much bottomfish accounts for changes, and (d) altered primary productivity (change productivity annually by 10% for both phytoplankton and benthic algae through an annual forcing factor of 0.9 and 1.1 on both groups). The hindcast simulations were performed to evaluate the importance of historical stressors to monk seal population dynamics by selecting the best-fit model for the monk seal biomass time series (1998-2015). Stressors included were (a) fishing with time series based on commercial fishery data, (b) environment with time series of the monthly PDO index as a multiplier for primary productivity, (c) additional mortality simulated with a constant removal of monk seals of varied intensities, and (4) combinations of these 3 stressors (2a and 2c being the most important with regard to the observed trend in monk seal population). Time series observation data of monk seal biomass and benthic bottomfish biomass, as well as catch time series of bank sharks (only for FFS), benthic and demersal bottomfish, bank jacks, and macroheterotrophs (lobsters) were loaded into Ecosim for model fitting. Refer to Weijerman et al (2017) for complete details.
  • Cite as: Weijerman, Mariska; Robinson, Stacie; Parrish, Frank; Polovina, Jeffrey; Littnan, Charles; Pacific Islands Fisheries Science Center (2019). Monk Seal Ecosystem Model Data: A Comparison of Ecosystem Structure and Energy Flows of Monk Seal Populations from Laysan Island and French Frigate Shoals in the Northwestern Hawaiian Islands from 1998 through 2015 (NCEI Accession 0190881). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://www.ncei.noaa.gov/archive/accession/0190881. Accessed [date].
gov.noaa.nodc:0190881
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Distributor NOAA National Centers for Environmental Information
+1-301-713-3277
NCEI.Info@noaa.gov
Dataset Point of Contact NOAA National Centers for Environmental Information
ncei.info@noaa.gov
Time Period 1998-01-01 to 2015-12-31
Spatial Bounding Box Coordinates
West: -172
East: -166
South: 23.5
North: 26
Spatial Coverage Map
General Documentation
Associated Resources
  • Pacific Islands Fisheries Science Center, 2017: Monk Seal Ecosystem Model Data: A Comparison of Ecosystem Structure and Energy Flows of Monk Seal Populations from Laysan Island and French Frigate Shoals in the Northwestern Hawaiian Islands, https://www.fisheries.noaa.gov/inport/item/35796.
  • Weijerman, M., Robinson, S., Parrish, F., Polovina, J., & Littnan, C. (2017). Comparative application of trophic ecosystem models to evaluate drivers of endangered Hawaiian monk seal populations. Marine Ecology Progress Series, 582, 215–229. https://doi.org/10.3354/meps12320
Publication Dates
  • publication: 2019-07-12
Data Presentation Form Digital table - digital representation of facts or figures systematically displayed, especially in columns
Dataset Progress Status Complete - production of the data has been completed
Historical archive - data has been stored in an offline storage facility
Data Update Frequency As needed
Supplemental Information
9 model data outputs and 2 data dictionaries are provided in this archival package.

Submission Package ID: KHJDLU
Purpose The main objective of this study was to understand the difference in ecosystem dynamics that could explain the observed decrease in monk seal biomass at French Frigate Shoals and the more stable biomass at Laysan. Specifically we investigated the relative influence of potential drivers -- including primary productivity, prey population, and predation -- on the monk seal populations in 40-year simulations and the external drivers of climate and fishing with an additional mortality on monk seals in hindcast simulations. Understanding the drivers and predictability of population trends will illuminate areas of focus for Hawaiian monk seal recovery efforts.
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  • accessLevel: Public
  • Distribution liability: NOAA and NCEI make no warranty, expressed or implied, regarding these data, nor does the fact of distribution constitute such a warranty. NOAA and NCEI cannot assume liability for any damages caused by any errors or omissions in these data. If appropriate, NCEI can only certify that the data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives.
Dataset Citation
  • Cite as: Weijerman, Mariska; Robinson, Stacie; Parrish, Frank; Polovina, Jeffrey; Littnan, Charles; Pacific Islands Fisheries Science Center (2019). Monk Seal Ecosystem Model Data: A Comparison of Ecosystem Structure and Energy Flows of Monk Seal Populations from Laysan Island and French Frigate Shoals in the Northwestern Hawaiian Islands from 1998 through 2015 (NCEI Accession 0190881). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://www.ncei.noaa.gov/archive/accession/0190881. Accessed [date].
Cited Authors
Principal Investigators
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Acknowledgments
  • Related Funding Agency: NOAA Pacific Islands Fisheries Science Center
Theme keywords NODC DATA TYPES THESAURUS NODC OBSERVATION TYPES THESAURUS WMO_CategoryCode
  • oceanography
CoRIS Discovery Thesaurus
  • Numeric Data Sets > Biology
CoRIS Theme Thesaurus
  • EARTH SCIENCE > Biosphere > Ecological Dynamics
  • EARTH SCIENCE > Biosphere > Zoology > Vertebrates
  • EARTH SCIENCE > Oceans > Marine Biology > Marine Mammals
  • EARTH SCIENCE > Oceans > Marine Biology > Marine Mammals > Pinnipeds
Global Change Master Directory (GCMD) Science Keywords Provider Keywords
  • Ecopath with Ecosim (EwE)
  • Hawaiian monk seal
  • bottomfish fishery
  • ecological modeling
  • monk seal
Data Center keywords NODC COLLECTING INSTITUTION NAMES THESAURUS NODC SUBMITTING INSTITUTION NAMES THESAURUS Global Change Master Directory (GCMD) Data Center Keywords
Place keywords NODC SEA AREA NAMES THESAURUS CoRIS Place Thesaurus
  • COUNTRY/TERRITORY > United States of America > Hawaii > Honolulu > French Frigate Shoals (24N166W0001)
  • COUNTRY/TERRITORY > United States of America > Hawaii > Honolulu > Laysan Island (25N171W0001)
  • COUNTRY/TERRITORY > United States of America > Hawaii > Honolulu > Northwestern Hawaiian Islands (28N178W0000)
  • OCEAN BASIN > Pacific Ocean > Central Pacific Ocean > Northwestern Hawaiian Islands (28N178W0000)
  • OCEAN BASIN > Pacific Ocean > Central Pacific Ocean > Northwestern Hawaiian Islands > French Frigate Shoals (24N166W0001)
  • OCEAN BASIN > Pacific Ocean > Central Pacific Ocean > Northwestern Hawaiian Islands > Laysan Island (25N171W0001)
Global Change Master Directory (GCMD) Location Keywords Provider Place Names
  • French Frigate Shoals
  • Laysan
  • Northwestern Hawaiian Islands
Project keywords Provider Project Names
  • Hawaiian Monk Seal Research Program
Keywords NCEI ACCESSION NUMBER
Use Constraints
  • Cite as: Weijerman, Mariska; Robinson, Stacie; Parrish, Frank; Polovina, Jeffrey; Littnan, Charles; Pacific Islands Fisheries Science Center (2019). Monk Seal Ecosystem Model Data: A Comparison of Ecosystem Structure and Energy Flows of Monk Seal Populations from Laysan Island and French Frigate Shoals in the Northwestern Hawaiian Islands from 1998 through 2015 (NCEI Accession 0190881). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://www.ncei.noaa.gov/archive/accession/0190881. Accessed [date].
Access Constraints
  • Use liability: NOAA and NCEI cannot provide any warranty as to the accuracy, reliability, or completeness of furnished data. Users assume responsibility to determine the usability of these data. The user is responsible for the results of any application of this data for other than its intended purpose.
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Lineage information for: dataset
Processing Steps
  • 2019-07-12T18:46:20Z - NCEI Accession 0190881 v1.1 was published.
Output Datasets
Lineage information for: dataset
Processing Steps
  • Parameter or Variable: BIOMASS (calculated); Units: tons/square kilometer; Observation Category: model output; Sampling Instrument: Not applicable; Sampling and Analyzing Method: Ecopath with Ecosim (EwE) version 6.4.4 was used to conduct sensitivity and hindcast simulations. Fish species were aggregated into functional groups and all biomass data was converted to metric tons per square kilometer and used as input data for the EwE models for Laysan and French Frigate Shoals. For the sensitivity assessment, four perturbation scenarios were simulated for a time span of 40 years (2010 through 2049): (a) baseline, (b) altered predator abundance, (c) altered monk seal prey abundance, and (d) altered primary productivity. The sensitivity assessment datasets include forecast simulations with monthly output for the last 5 years of the 40-year simulation run (2044-2049). Monthly output includes mean biomass of a variety of marine organisms, such as seabirds, sharks, fish, turtles, plankton, and algae. For the hindcast simulations, historical stressors to monk seal population dynamics were evaluated by selecting the best-fit model for monk seal biomass time series (1998-2015). The hindcast simulation datasets for 1998 through 2015 include simulated monk seal and bottomfish biomass factoring a few key external drivers (fishing with time series based on commercial fishery data and additional mortality simulated with a constant removal of monk seals of varied intensities being the most important). Time series observation data of monk seal biomass and benthic bottomfish biomass, as well as catch time series of bank sharks (only for FFS), benthic and demersal bottomfish, bank jacks, and macroheterotrophs (lobsters) were loaded into Ecosim for model fitting. Best-fit of model-simulated output data and observational data was based on the least square fitting criterion and summed the squared deviations. Additionally, the Akaike's information criterion (AIC) was calculated taking into account the small sample size. Refer to Weijerman et al (2017) for complete details. Weijerman M, Robinson S, Parrish F, Polovina J, Littnan C (2017) Comparative application of trophic ecosystem models to evaluate drivers of endangered Hawaiian monk seal populations. Mar Ecol Prog Ser 582:215-229. https://doi.org/10.3354/meps12320; Data Quality Method: Model dynamics were validated with a hindcast simulation (1998-2015). Time series data of monk seal biomass and bottomfish biomass were loaded into Ecosim for validation and to fine-tune the model by adjusting vulnerability values and so minimize the residuals between predicted and observed time series of monk seal and bottomfish biomass using a least-square fitting criterion. We manually adjusted vulnerability values of interest based on the results from the perturbation scenarios and restricted them to ecological meaningful values (i.e., preferably between 1 and 3 with 10 as maximum value)..
Last Modified: 2024-06-30T12:54:03Z
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