DOI: 10.5061/dryad.rv15dv4fw
title: Discovery of an unidentified species of nicothoid copepod infesting cancrid crabs in Santa Barbara, California

description: A previously unobserved and potentially novel copepod egg
 predator (Nicothoidae cf. Choniosphaera sp.) was
 recently discovered in the egg masses and gills of three
 commercially important rock crab species (Metacarcinus anthonyi,
 Romaleon antennarium, and Cancer productus) along the Gaviota
 Coast of Southern California west of Santa Barbara. Nicothoid egg
 predators have never been observed in crabs along the Pacific coast of the
 Americas, despite extensive historical work on cancrid crab brood
 mortality caused by nemertean egg predators in the 1990s. This outbreak is
 a recent and possibly unique event. Female copepods appear highly
 modified, mimicking the coloration and globular shape of crab eggs. The
 copepods feed by puncturing a small hole in the shell of the crab egg,
 aborting the development of the embryo, and subsequently facilitating
 entry of microbial agents. We document high copepod prevalence in
 ovigerous crabs along the Santa Barbara coast. Lack of fishery management
 coupled with the geographical extent and host specificity of this
 potential threat to rock crab populations warrants further investigation.
description: See publication supplemental documentation (Appendix S1) for full
 methods.  
description: # Data Descriptions Cells infilled with NA indicate that information is
 not applicable. ## 1. metadata.csv * description: a CSV which contains the
 metadata collected for each individual crab collected and monitored during
 the duration of this study * format: csv * variables: * **crab_id**: the
 unique identification tag given to each individual crab and follows the
 structure below 1. species (first three letters of species name) * options
 include: 1. *Cancer anthonyi* (*Metacarcinus anthonyi*): ANT 2. *Cancer
 productus*: PRO 3. *Cancer antennarius* (*Romaleon antennarium*): ATS 1.
 location (first three letters of collection location) * options include:
 1. Gaviota coast: GAV 2. Unknown: UNK 3. Alegria Beach: ALE 4. Sripps: SIO
 5. Hendry’s Beach: HNE 1. unique number (unique number starting with 001)
 for individuals that are NOT sexually mature females (i.e. males or
 immature females), the species name will be given a prefix of M for males
 and IF for immature females * examples: 1. sexually mature female
 *Metacarcinus anthonyi* from the Gaviota Coast: ANT-GAV-001 2. sexually
 immature female *Cancer productus* from Alegria Beach: IFPRO-ALE-001 3.
 male *Romaleon antennarium* from Gaviota Scripps: MATS-SIO-001 *
 **collection_date**: the date that the individual was collected from the
 baited crab pot and brought into the lab for examination * the date is
 formatted as MM/DD/YYYY * **species**: the species of rock crab * options
 include: 1. *Cancer anthonyi* (*Metacarcinus anthonyi*): cancer_anthonyi
 2. *Cancer productus*: cancer_productus 3. *Cancer antennarius* (*Romaleon
 antennarium*): cancer_antennarius * **carapace_width**: the length of the
 carapce in mm - measured using the standard practices outlined in The
 Light and Smith Manual by James Carlton * **abdomen_width**: the length of
 the abdomen in mm * measured using the standard practices outlined in The
 Light and Smith Manual by James Carlton * **sex**: the sex of the
 individual - options include: 1. sexually mature female: F 2. immature
 female: IF 3. male: M * **gravid**: the status of sexually mature females,
 either classified as gravid (yes) or not gravid (no) - options include: 1.
 yes: Y 2. no: N 3. not applicable (for immature females IF or males M): NA
 * **eds**: the egg development stage (EDS) of the egg mass for gravid
 sexually mature females as outlined in the supplemental material (Appendix
 S1: Table S1) of the associated manuscript * this is the EDS of the
 majority of the brood on the date of collection * **location**: the
 location of collection - options include: 1. Gaviota coast: gaviota 2.
 Unknown: unknown 3. Alegria Beach: alegria 4. Scripps: scripps 5. Hendry’s
 Beach: hendrys * **notes**: these are notes about the general appearance
 and the prevalence of nicothoids upon initial examination * **nico_date**:
 the date that nicothoids were first identified infesting the individual -
 the date is formatted as MM/DD/YYYY * **first_location**: the first
 location that nicothoids were found infested the individual - options
 include: 1. egg mass of gravid sexually mature females: eggs 2. gill
 chamber: gills 3. not applicable (nicothoids were not found): NA *
 **dissected**: was the individual dissected, yes or no - options include:
 1. yes 2. no * **nico_location**: the locations which nicothoids were
 found infesting the individual - options include: 1. ONLY the egg mass of
 gravid sexually mature females: egg_mass 2. ONLY the gill chamber: gills
 3. BOTH the egg mass of gravid sexually mature females and the gill
 chamber: both 4. nicothoids were not found infesting the individual:
 neither 5. not applicable (died before examination or insufficient search
 effort): NA * **ever_gravid**: was the sexually mature female ever gravid
 during the duration of the observation, yes or no - options include: 1.
 yes: Y 2. no: N 3. not applicable (for immature females IF or males M): NA
 * **final_notes**: these are final notes recoreded about the individual
 during the duration of the observation including if the individual died
 before examination, if the individual molted, or other notable features *
 **analysis_status**: whether or not the individual should be included in
 the analysis - options include: 1. exclude from analysis (see final notes
 for justification): exclude 2. include in analysis (blank): ## 2.
 dissection_data.csv * description: a CSV which contains the dissection
 data collected for each individual dissection performed during the
 duration of this study * format: csv * variables: * **dissection_id**: the
 unique identificaiton tag given to each dissection and follows the
 structure below 1. Dissection 2. unique number (unique number starting
 with 001) * example: the first dissection: Dissection-001 * **crab_id**:
 the unique identifcation tag given to each indvidual crab and follows the
 structure below 1. species (first three letters of species name) * options
 include: 1. *Cancer anthonyi* (*Metacarcinus anthonyi*): ANT 2. *Cancer
 productus*: PRO 3. *Cancer antennarius* (*Romaleon antennarium*): ATS 1.
 location (first three letters of collection location) * options include:
 1. Gaviota coast: GAV 2. Unknown: UNK 3. Alegria Beach: ALE 4. Sripps: SIO
 5. Hendry’s Beach: HNE 1. unique number (unique number starting with 001)
 for individuals that are NOT sexually mature females (i.e. males or
 immature females), the species name will be given a prefix of M for males
 and IF for immature females * examples: 1. sexually mature female
 *Metacarcinus anthonyi* from the Gaviota Coast: ANT-GAV-001 2. sexually
 immature female *Cancer productus* from Alegria Beach: IFPRO-ALE-001 3.
 male *Romaleon antennarium* from Gaviota Scripps: MATS-SIO-001” * **sex**:
 the sex of the individual * options include: 1. sexually mature female: F
 2. immature female: IF 3. male: M * **species**: the species of rock crab
 * options include: 1. *Cancer anthonyi* (*Metacarcinus anthonyi*):
 cancer_anthonyi 2. *Cancer productus*: cancer_productus 3. *Cancer
 antennarius* (*Romaleon antennarium*): cancer_antennarius * **date**: the
 date of the dissection * the date is formatted as MM/DD/YYYY *
 **nico_count**: the total count of larval nicothoids (the only life stage
 present in the gill chamber) found across the one gill removed and
 examined from the host * **number_lamellae**: the total count of lamallae
 found across the one gill removed and examined from the host * **notes**:
 these are general notes about the dissection and any significant findings
 * **analysis_status**: whether or not the individual should be included in
 the analysis - options include: 1. exclude from analysis (see final notes
 for justification): exclude 2. include in analysis (blank): ## 3.
 egg_mass_data.csv * description: a CSV which contains the egg mass
 examination data collected for each crab monitored during the duration of
 this study * format: csv * variables: * **trial_id**: the unique
 identification tag given to each egg mass examination - egg mass
 examinations occurred during two investigations studying autoinfection and
 egg mass moratlity; therefore the naming follows the structure below 1.
 investigation name * options include: 1. Autoinfection 2. Mortality 1.
 unique number (unique number starting with 001 for each investigation) *
 examples: 1. first autoinfection investigation: Autoinfection-001 2. first
 egg mass mortality investigation: Mortality-001 * **crab_id**: the unique
 identifcation tag given to each indvidual crab and follows the structure
 below 1. species (first three letters of species name) * options include:
 1. *Cancer anthonyi* (*Metacarcinus anthonyi*): ANT 2. *Cancer productus*:
 PRO 3. *Cancer antennarius* (*Romaleon antennarium*): ATS 1. location
 (first three letters of collection location) * options include: 1. Gaviota
 coast: GAV 2. Unknown: UNK 3. Alegria Beach: ALE 4. Sripps: SIO 5.
 Hendry’s Beach: HNE 1. unique number (unique number starting with 001) for
 individuals that are NOT sexually mature females (i.e. males or immature
 females), the species name will be given a prefix of M for males and IF
 for immature females * examples: 1. sexually mature female *Metacarcinus
 anthonyi* from the Gaviota Coast: ANT-GAV-001 2. sexually immature female
 *Cancer productus* from Alegria Beach: IFPRO-ALE-001 3. male *Romaleon
 antennarium* from Gaviota Scripps: MATS-SIO-001” * **date**: the date of
 the examination * the date is formatted as MM/DD/YYYY * **eds**: the egg
 development stage (EDS) of the egg mass for gravid sexually mature females
 as outlined in the supplemental material (Appendix S1: Table S1) of the
 associated manuscript * this is the EDS of the majority of the brood on
 the date of examination * **day**: the day in the developmental period of
 the host egg mass that corresponds to the date of the examination * this
 is extrapolated based on known developmental periods for each species and
 the timeline of examinations and corresponding egg development stages
 (eds) records * **pleopod_number**: the numerical location of the pleopod
 from which the sample that was examined was removed prior to investigation
 * the pleopods are numbered 1- 8 starting with the left posterior pleopod
 from the ventral view as number 1 and moving in a counterclockwise fashion
 increasing through the final pleopod, number 8 * **crab_eggs**: the total
 number of crab eggs counted in the smaple during the examination *
 **adult_nicos**: the total number of adult nicothoid copepods counted in
 the sample during the examination * **larval_nicos**: the total number of
 larval nicothoid copepods counted in the sample during the examination *
 **nico_eggs**: the total number of nicothoid copepod eggs counted in the
 sample during the examination * **nemerteans**: the total number of
 nemertean worms counted in the sample during the examination ## 4.
 locations.csv * description: a CSV which contains the egg mass examination
 data collected for each crab monitored during the duration of this study *
 format: csv * variables: * **family**: the family of the copepod egg
 predator, nicothoidae * **genus**: the genus of the copepod egg predator,
 choniosphaera * **species**: the species of the copepod egg predator *
 options include: 1. Ch. cancrorum 2. Ch. maenadis 3. Ch. indica 4. Ch. sp.
 * **host_species**: the Latin name of the host species which was infested
 by the egg predator copepod * **region**: the country where the species of
 copepod egg predator was found * **subregion**: the subregion of the
 country where the species of copepod egg predator was found *
 **location**: the most precise location, a body of water, where the
 species of copepod egg predator was found * **longitude**: the longitude
 for the most precise location for the copepod egg predator * **latitude**:
 the latitude for the most precise location for the copepod egg predator *
 **year**: the year of the discovery of this copepod egg predator on this
 particular host species * **author**: the author of the corresponding
 paper * **host_group**: the group of the host species, brachyura *
 **host_order**: the order of the host species, decapoda * **paper**: the
 paper corresponding to the first recording of this particular copepod egg
 predator on the various host species * **notes:** these are notes about
 the status of the species within the genus