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

Description

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.

Resources

Name Format Description Link
0 Pacific Islands Fisheries Science Center website. https://www.pifsc.noaa.gov/hawaiian_monk_seal/
33 NOAA Data Management Plan for this record on InPort. https://www.fisheries.noaa.gov/inportserve/waf/noaa/nmfs/pifsc/dmp/pdf/35796.pdf
0 Monthly output of ecosystem modeling data for the last 5 years of 40-year simulation run for Laysan and French Frigate Shoals where we increased Primary Producers by 10%. https://accession.nodc.noaa.gov/0190881
0 Monk seal observation data from 1998 - 2015 and bottomfish observation data from 1998 to 2010. These data sets were used to compare model output data with to assess which simulation has the best fit and is therefore most likely to explain the factors contributing to the monk seal trends. https://accession.nodc.noaa.gov/0190881
0 Global Change Master Directory (GCMD). 2024. GCMD Keywords, Version 19. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords
0 Monthly output of ecosystem modeling data for the last 5 years of 40-year simulation run for Laysan and French Frigate Shoals where we decreased Primary Producers by 10%. https://accession.nodc.noaa.gov/0190881
0 Monthly output of ecosystem modeling data for the last 5 years of 40-year simulation run for Laysan and French Frigate Shoals where we decreased the biomass of the monk seal predators - Sea Birds, Tiger Sharks, Reef Sharks, Reef Jacks, Subphotic Piscivores - by 30%. https://accession.nodc.noaa.gov/0190881
0 View the complete metadata record on InPort for more information about this dataset. https://www.fisheries.noaa.gov/inport/item/35796
0 Monthly output of ecosystem modeling data from 1998 through 2015 for Laysan and French Frigate Shoals where we included a bottomfish fishery and an additional mortality on monk seals to assess its importance on the observed trend in monk seal population. For Laysan, the best fit with the observed data was fishery + 1 % removal, and for French Frigate Shoals it was fishery + 7% removal. https://accession.nodc.noaa.gov/0190881
0 Pacific Island Fisheries Science Center homepage https://www.pifsc.noaa.gov
0 Monthly output of ecosystem modeling data for the last 5 years of 40-year simulation run for Laysan and French Frigate Shoals with no additional drivers. This data set serves as the baseline. https://accession.nodc.noaa.gov/0190881
0 Monthly output of ecosystem modeling data for the last 5 years of 40-year simulation run for Laysan and French Frigate Shoals where we decreased in monk seal prey including bottomfish - Mesophotic Benthic Carnivores, Mesophotic Plantivores, Mesophotic Forage Fish, Bottomfish - by 30%. https://accession.nodc.noaa.gov/0190881
0 Monthly output of ecosystem modeling data for the last 5 years of 40-year simulation run for Laysan and French Frigate Shoals where we decreased monk seal prey - Mesophotic Benthic Carnivores, Mesophotic Plantivores, Mesophotic Forage Fish - by 30%. https://accession.nodc.noaa.gov/0190881
0 Monthly output of ecosystem modeling data from 1998 - 2015 for Laysan (LAY) and French Frigate Shoals (FFS) where we included a bottomfish fishery only to assess its importance on the observed trend in monk seal population. https://accession.nodc.noaa.gov/0190881
27 Ecological/ecosystem modeling software website. https://ecopath.org

Tags

  • ecopath with ecosim
  • doc/noaa/nmfs/pifsc
  • united states of america
  • north pacific ocean
  • pifsc
  • biosphere
  • laysan
  • protected species division
  • oceans
  • ecosystem modeling
  • bottomfish fishery
  • ecological modeling
  • pmnm
  • papahanaumokuakea marine national monument
  • noaa
  • numeric data sets
  • hawaiian monk seal
  • hawaii
  • nmfs
  • biology
  • us doc
  • vertebrates
  • pacific islands fisheries science center
  • u.s. department of commerce
  • earth science
  • national marine fisheries service
  • french frigate shoals (24n166w0001)
  • nwhi
  • marine mammals
  • pinnipeds
  • marine biology
  • ewe
  • honolulu
  • northwestern hawaiian islands (28n178w0000)
  • central pacific ocean
  • biomass
  • french frigate shoals
  • monk seal
  • ocean basin
  • ecosystem sciences division
  • laysan island (25n171w0001)
  • northwestern hawaiian islands
  • zoology
  • pacific ocean
  • ecological dynamics
  • country/territory
  • psd
  • recovery
  • model output

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