DOI: 10.5061/dryad.66t1g1kcs
title: Marine mammal recovery is associated with the resurgence of a nematode parasite

description: As the oceans change, the abundance of parasites and risk of infection to
 marine mammals may also be changing. Nematodes in the family Anisakidae
 can harm marine mammals and recent studies have revealed a global increase
 in these parasites, but the cause is unknown. We sought to determine how
 anisakid risk in Puget Sound had changed over 98 years by conducting
 parasitological analysis of museum specimens of the prey species of marine
 mammals. We dissected Pacific Herring, Walleye Pollock, Surf Smelt,
 Pacific Hake, and Copper Rockfish collected between 1920 and 2018. We
 found that the larval anisakid Contracaecum spp. was the most abundant
 marine mammal parasite in these prey fish. We used a state-space model to
 assess the relationship between Contracaecum spp. abundance and time, with
 harbor seal abundance and sea surface temperature as potential correlates.
 We detected an overall decline in Contracaecum spp. abundance with a
 recent uptick starting in 1989, which was correlated with increasing
 harbor seal abundance. While these data reveal a regional trend, increases
 in marine mammal parasites in response to marine mammal protection have
 occurred elsewhere, and suggest that the phenomenon might be more
 widespread than is currently appreciated. Marine mammals in Puget Sound
 are probably less burdened by anisakids than they were historically, but
 the recent recovery of anisakids could impact the health of these hosts,
 which today face very different stressors than they did in the past.
description: # Marine mammal recovery is associated with the resurgence of a nematode
 parasite --- Dataset includes anisakid (*Contracaecum* and *Anisakis*
 spp.) data collected from natural history specimens of five species of
 fish hosts collected from 1880-2018 in Puget Sound, Washington. These
 files include Pacific hake (hake_2022.02.21.csv), Pacific herring
 (herring_2022.02.23.csv), walleye pollock (pollock_2022.02.21.csv), copper
 rockfish (rockfish_2022.02.21.csv), and surf smelt (smelt_2022.02.21.csv).
 There is also harbor seal abundance data from Chasco et al. 2017,
 pollutant data from Brandenberger et al. 2008, and temperature data from
 Race Rocks lighthouse (48.2980°N, 123.5315°W) British Columbia
 Lightstation Sea-Surface Temperature and Salinity Data. ## Description of
 the Data and file structure Each fish species' anisakid count and
 metadata are all housed in independent .csv files (smelt_2022.02.21.csv,
 rockfish_2022.02.21.csv, pollock_2022.02.21.csv, herring_2022.02.23.csv,
 hake_2022.02.21.csv). For analysis, the fish data (hake, herring, pollock,
 rockfish, and smelt) have been compiled into one dataset in the
 compiled_data.RDS file. The other data (temperature, pollutants, and
 harbor seal abundance estimates) are derived from the publications listed
 below. #### **hake_2022.02.21.csv , herring_2022.02.23.csv ,
 pollock_2022.02.21.csv , rockfish_2022.02.21.csv , smelt_2022.02.21.csv**
 Year.Collected: the year the fish was collected from the wild and
 preserved in the Burke Museum's Ichthyology collection Columns named
 in the format XX_XX_XX: the count of each genus of parasites found in each
 fish, the suffix indicating the initials of the scientific name of that
 species in some cases, or "all" in others, where it was found in
 more than one species. For example, Anisakis_sp_all indicates Anisakis sp.
 nematodes found throughout the body of the particular host. latjitt site:
 the collection site latitude, but the coordinate has been
 "jittered" by +/- a small amount to reduce overlap in mapping
 and analysis. Fish.ID: the catalog number of each fish dissected
 Standard.Length..mm.: standard length of the fish in mm Total.Length..mm.:
 total length of the fish in mm long: longitude the fish was collected lat:
 latitude the fish was collected fish_density: an estimate of the density
 of the fish in Puget Sound from that year X: year since 1920 temp_na_rm:
 average temperature, calculated with NAs removed. Data compiled from Race
 Rocks Temperature data, temperature with NAs removed sTemp: temperature
 standardized to a value between 0-1. Pb: average lead reading for that
 year in μg/g As: average arsenic reading for that year in μg/g Zn: average
 zinc reading for that year in μg/g Ni: average nickel reading for that
 year in μg/g V: average vanadium reading for that year in μg/g Cr: average
 chromium reading for that year in μg/g Cu: average copper reading for that
 year in μg/g Ba: average barium reading for that year in μg/g Be: average
 beryllium reading for that year in μg/g Sig8_lignin: average lignin
 reading for that year in mg/g Lamb8: average soil biomarker concentration
 reading for that year Bd.V_soil_biomarker: average soil biomarker
 concentration reading for that year #### **compiled_data.RDS** In this
 compiled dataset, each row is a parasite species in an individual fish.
 The columns represent different variables: site: the latitude and
 longitude the fish was collected year: the year the fish was collected
 fish.id: the institution and catalog number of the fish length: the
 standardized length of the fish long: longitude collected lat: latitude
 collected fish species: general common name of the fish para.spc: the
 species of parasite collected from the fish count: the number of parasites
 collected of that species from the fish sfish_density: when available, the
 standardized population density of that fish species in that year
 temp_na_rm: the water temperature from that year, with NAs removed, from
 Race Rocks bd.v_soil_biomarker: average soil biomarker concentration
 reading for that year par.type: general type of parasite lifecycle: type
 of parasite life cycle, direct (single host) or complex (multihost)
 nhosts: number of hosts needed to complete the parasite's life cycle
 terminal: whether the species was a terminal host or not,  0 = no, 1 =
 yes, 2 = "unknown" ord2raw: PC2 from the PCA compiling pollutant
 information ord1raw: PC1 from the PCA compiling pollutant information
 ord2: LOESS prediction of PC2 ord1: LOESS prediction of PC1 temp_smooth:
 the simple moving average (sma) of the temperature for that year ##
 Sharing/access Information Links to other publicly accessible locations of
 the data:
 [https://github.com/wood-lab/Mastick_et_al_Ecology](https://github.com/wood-lab/Mastick_et_al_Ecology) Data derived from the sources below: Wood CL, Welicky RL, Preisser WC, et al. 2023 A reconstruction of parasite burden reveals one century of climate-associated parasite decline. Proc Nat Acad Sci 120: e2211903120. Brandenberger JM, Crecelius EA, Louchouarn P. 2008 Historical inputs and natural recovery rates for heavy metals and organic biomarkers in Puget Sound during the 20th century. Environ Sci Technol 42: 6786–90. Chasco B, Kaplan IC, Thomas A et al. 2017 Estimates of Chinook salmon consumption in Washington State inland waters by four marine mammal predators from 1970 to 2015. Can J Fish Aquat Sci 74: 1173–94. British Columbia Lightstation Sea-Surface Temperature and Salinity Data (Pacific), 1914-present. [https://open.canada.ca/data/en/dataset/719955f2-bf8e-44f7-bc26-6bd623e82884](https://open.canada.ca/data/en/dataset/719955f2-bf8e-44f7-bc26-6bd623e82884). Strom A, Francis RC, Mantua NJ, Miles EL, Peterson DL. 2004 North Pacific climate recorded in growth rings of geoduck clams: a new tool for paleoenvironmental reconstruction. Geophysical Research Letters, 31(6).