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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

    Metadata Updated: March 16, 2024

    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.

    Access & Use Information

    License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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    Dates

    Metadata Date February 29, 2024
    Metadata Created Date November 12, 2020
    Metadata Updated Date March 16, 2024
    Reference Date(s) November 6, 2017 (publication)
    Frequency Of Update notPlanned

    Metadata Source

    Harvested from NMFS PIFSC

    Other Data Resources

    Additional Metadata

    Resource Type Dataset
    Metadata Date February 29, 2024
    Metadata Created Date November 12, 2020
    Metadata Updated Date March 16, 2024
    Reference Date(s) November 6, 2017 (publication)
    Responsible Party (Point of Contact, Custodian)
    Contact Email
    Guid gov.noaa.nmfs.inport:35796
    Access Constraints Cite As: Pacific Islands Fisheries Science Center, [Date of Access]: 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 [Data Date Range], https://www.fisheries.noaa.gov/inport/item/35796., Access Constraints: None, Use Constraints: Please cite PIFSC Ecosystem Sciences Division (ESD) when using the data. Suggested citation: 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, https://www.fisheries.noaa.gov/inport/item/35796., Distribution Liability: While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such warranty.
    Bbox East Long -166
    Bbox North Lat 26
    Bbox South Lat 23.5
    Bbox West Long -172
    Coupled Resource
    Frequency Of Update notPlanned
    Harvest Object Id f397a782-db16-48ed-9b4f-15f74ad5f4c8
    Harvest Source Id c0beac72-5f43-4455-8c33-1b345fbc2dfe
    Harvest Source Title NMFS PIFSC
    Licence NOAA provides no warranty, nor accepts any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data. It is the responsibility of the user to determine whether or not the data is suitable for the intended purpose.
    Lineage Input data was collected for the Ecopath with Ecosim model (EwE) from Parrish et al 2011; PIFSC Ecosystem Sciences Division data, monk seal data, bottomfish stock asessment data, and other sources defined in Weijerman et al 2017 MEPS. The model output data is generated with the EwE model. See Weijerman et al 2017 MEPS for details.
    Metadata Language eng
    Metadata Type geospatial
    Old Spatial {"type": "Polygon", "coordinates": [[[-172.0, 23.5], [-166.0, 23.5], [-166.0, 26.0], [-172.0, 26.0], [-172.0, 23.5]]]}
    Progress completed
    Spatial Data Service Type
    Spatial Reference System
    Spatial Harvester True
    Temporal Extent Begin 1998-01-01
    Temporal Extent End 2015-12-31

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