Life History Data Matrix Overview

This Life History Data Matrix (LHDM) was developed to provide comprehensive information on individual eastern north Pacific (ENP) chondrichthyan species and clearly indicate which aspects of their life history and distribution remain unknown. Although details in the LHDM are primarily drawn from the ENP, information from work conducted in other regions is included for species where there is limited or no ENP information available, or based on editorial discretion. When information was included from outside the ENP, it was obtained from the nearest adjacent region whenever possible.

The LHDM is organized into 5 Microsoft Excel worksheets and arranged systematically (following Compagno 2001) based upon Superorder and Order of the species. The organization is as follows:

• Worksheet 1
• Superorder: Squalormorphii
• Orders: Hexanchiformes, Squaliformes, and Squatiniformes
  
  
• Worksheet 2
• Superorder: Squalormorphii
• Order: Rajiformes
  
  
• Worksheet 3
• Superorder: Galeomorphii
• Orders: Heterodontiformes, Orectolobiformes, and Lamniformes
  
  
• Worksheet 4
• Superorder: Galeomorphii
• Order: Carcharhiniformes
  
  
• Worksheet 5
• Subclass: Holocephali
• Order: Chimaeraformes

Reference sources for all information within the LHDM are clearly noted within each cell or subsequently in an adjacent column. Details based on primary literature are indicated by black font, while gray literature, which includes student theses, technical reports, and personal communications, is listed in blue. Within a column, information is arranged primarily by amount available from the sources, with more informative sources placed higher in the column. In the case where there are sources with an equivalent amount of information, they are arranged chronologically.

Units of measurement are provided either in each cell or in the column heading. If information in a cell pertains to males, females, or both sexes, the appropriate sex is listed in bold at the beginning of the cell. If no sex was indicated by the source, then no sexual designation is listed. When no information is available, one of three abbreviations is given: NF, NG, or NA.

NF: Not Found Refers to a parameter for which no information was
found. (Either it does not exist, or we could not find it in the literature.)

NG: Not Given Refers to a study where similar parameters are provided, but not the specified parameter.

NA: Not Applicable Refers to a life history parameter that is not valid for a species.

Taxonomy

In the LHDM, taxonomy is arranged in the following, hierarchical order, which follows the taxonomic designations of Compagno (2001): Superorder, Order, Family, Genus, and Species. The species are arranged systematically down to the family level. The genera are arranged alphabetically within the family, as are species within a genus.

• Author: The person that first described the genus or species and the year of the description. If the species has been placed in a new genus since the original description, then the new author's name is placed in parentheses.
  
  
• Synonymy: The chronological list of the scientific names that have been applied to a species, including the authors and dates of publication. Only synonyms from the ENP are included.
  
  
• Common Name: The local or vernacular name for a species. The common name can vary regionally, whereas there is only one scientific name. The most widespread or primary common name is in bold and primarily follows Compagno (1999), but different common names are listed where appropriate. Only English common names from the ENP are included.

Biogeography

The geographic and depth distribution of a given species.

• Eastern North Pacific: The distribution of the species in the ENP.
  
  
• Global: The worldwide distribution of the species.
  
  
• Observed Depth Range: The range of depths at which the species is known to occur.

Age and Growth

Information on the growth rates and longevity of a species.

• Total Length (cm) to Weight (kg) Equation (Location): Equation describing the length-weight relationship. The study location is noted in parentheses.
  
  
• Length Conversion Equations (Location): Equations that convert one measurement of length to another, such as converting total length (TL) to precaudal length (PCL). Length measurements included in the LHDM are: total length (TL), standard length (SL), precaudal length (PCL), fork length (FL), disc width (DW), and alternate length (AL). Alternate length is always defined. The study location is noted in parentheses.
  
  
• Max Reported Length (cm): The maximum reliable recorded length and type of measurement.
  
  
• Geographic Area (of Max Length): Area where maximum length was recorded. The reference for this cell is listed in the preceding max reported length column.
  
  
• Length at Birth (cm): Size or size range at the time of parturition.
  
  
• Geographic Area (Length of Birth): Study location. The reference for this cell is listed in the preceding length at birth column.
  
  
• Growth Parameters: In this section, all information in a particular row is derived from the same study, which is listed at the end of the section in the Source (Age and Growth Study) column.
  
  
• L_inf in cm: Asymptotic length or theoretical maximum length. Variability listed in parentheses refers to the 95% confidence interval (95% C.I.), standard error (S.E.), or standard deviation (S.D.).
  
  
• k: Growth coefficient. Variability listed in parentheses refers to the 95% confidence interval (95% C.I.), standard error (S.E.), or standard deviation (S.D.).
  
  
• t_o: Size at which a species would theoretically have been at age zero. Variability listed in parentheses refers to the 95% confidence interval (95% C.I.), standard error (S.E.), or standard deviation (S.D.).
  
  
• r²: Coefficient of determination.
  
  
• Growth Model: Model used to derive the growth parameters.
  
  
• Ageing Method(s): Method used to age a species. Includes such information as which structure was used, how it was prepared, and technique used to age the structure. Information may also be derived from a number of other techniques such as length-frequency analysis or back calculations.
  
  
• Validation: Method used to validate age estimates.
  
  
• Verification: Method used to verify age estimates.
  
  
• Geographic Area (of Age and Growth Study): Study location.
  
  
• Source (Age and Growth Study): Author and date of publication for age and growth study.
  
  
• Longevity: Estimate of maximum age.
  
  
• Method of Longevity Estimation: Technique used to derive longevity estimate. The reference for this cell is listed in the preceding max reported length column.
  
  

Reproduction

Information on reproductive biology, includes details on the mode of reproduction, development, maturity, reproductive cycle, fecundity, and courtship and nursery grounds.

• Breeding Behavior (Mode of Reproduction): The method used to nourish and give birth to developing offspring. For the purposes of the LHDM there are three categories: oviparity, aplacental viviparity, and placental viviparity.
  
  
  • Oviparity: embryos are completely reliant upon yolk and are enclosed in a thick egg case, which the mother then lays externally.
  • Aplacental viviparity: This mode includes three types: 1) embryos develop in the uterus with only the yolk sac for nourishment (aplacental yolk sac variety); 2) embryos develop with a yolk sack, which is supplemented by the production of histotroph by the mother via uterine villi (aplacental with uterine villi ); 3) embryos feed on ovulated eggs or other embryos (aplacental with oophagy and intrauterine cannibalism).
  • Placental viviparity: Embryo's yolk sac or yolk stalk converts into a placenta or umbilical cord, which allows for metabolic exchange between the mother and embryo.
    
    
• Sexual Dimorphism: The development of secondary sexual characteristics that result in different morphologies for males and females
  
  
• Length (cm) & Age at 1st Maturity: Size or size range at which males and females first become sexually mature. Corresponding rows in adjacent male and female columns contain information derived from the same source.
  
  
• 50% Maturity: Size or size range at which 50% of the males and females in a population are sexually mature. Corresponding rows in adjacent male and female columns contain information derived from the same source.
  
  
• Geographic Area
  
  
• Courtship: Areas where courtship and copulation have been directly observed. Information is arranged geographically from north to south.
  
  
• Nursery: Areas where females have been observed birthing young or depositing eggs and/or where high numbers of neonates have been found. Information is arranged geographically from north to south.
  
  
• Seasonal Cycle: Times of year when courtship, fertilization, egg-deposition, and parturition are known to occur. These aspects of reproduction are color-coded and listed by month. Month columns may also be labeled with ^^^^^ to indicate periods of peak fertilization, ***** to indicate periods of peak pupping, and ##### to indicate doubtful pupping records.
  
  
• Source (Location) (Seasonal Cycle): Author and date of publication of the source for the seasonal cycle information. The location where the study occurred is included in parentheses. Information is arranged geographically from north to south.
  
  
• Reproductive Cycle: The length of time between litters.
  
  
• Fecundity Range and/or Mean Ovarian Eggs: Number (or range) of ovarian eggs in adult females.
  
  
• Uterine Eggs: Number (or range) of uterine eggs in adult females.
  
  
• Embryos: Number (or range) of embryos in adult females.
  
  
• Sex Ratio at Birth (M:F): The ratio of males to females in a litter.
  
  
• Uterine Egg or Embryo Number at Female TL (cm) or Age: Number of eggs or embryos in a female of a particular length or age.
  
  
• Size Specific Fecundity Equations (length or weight range): Equation that estimates the theoretical number of embryos a female of a specific size should have.
  
  
• Gestation Time: The amount of time between fertilization and parturition.
  
  

Mortality

Information on mortality rates, or the proportion of a population that dies in a given time frame. In this section all information in a particular row comes from the same study, which is listed at the end of the section in the Source (Mortality Estimates) column.

• Natural (M): Instantaneous rate of natural mortality.
  
  
• Fishing (F): Instantaneous rate of fishing mortality.
  
  
• Total (Z): Instantaneous rate of total mortality (Z = M + F).
  
  
• Method of Mortality Estimation: Method used to derive mortality estimates.
  
  
• Age Range Used to Calculate Mortality: Age range used in the calculation of mortality estimates (dependent on the method used).
  
  
• Source (Mortality Estimates): Author and date of publication of the source for the mortality information.
  
  

Demography

Population dynamics and characteristics. In this section all information in a particular row comes from the same study, which is listed at the end of the section in the Source (of Demography Study) column.

• r: Instantaneous or intrinsic rate of increase.
  
  
• e^r (lambda): Finite rate of increase.
  
  
• R₀: Net reproductive rate. The mean number of female produced per female over her entire life.
  
  
• G(T): Generation Time. The average length of time it takes for a female to give birth to her first female offspring, or the average age of all reproductive females in a population.
  
  
• c_x/w_x: Stable age/stage distribution. This indicates the theoretical relative proportion of individuals present in each age class or stage.
  
  
• Method: Technique used to calculate demographic parameters.
  
  
• Geographic Region: Study location.
  
  
• Source (Demography Study): Author and date of publication of the source for demographic information.
  
  

Habitat Association & Trophic Interactions

Stage specific information on habitat associations and trophic interactions.

• Juveniles: Neonates and immature animals.
• Habitat: habitat utilized by juveniles.
• Diet: Prey items of juveniles. Major categories of prey are in bold, and all prey items are identified to the lowest possible taxonomic level, including family, genus and species.
• Foraging Strategy: Behavior exhibited during foraging and/or feeding.
• Periodicity: Time of day during which juveniles feed.
• Predators: Known predators of juveniles.
  
  
• Adolescents: Maturing animals.
• Habitat: habitat utilized by adolescents.
• Diet: Prey items of adolescents. Major categories of prey are in bold, and all prey items are identified to the lowest possible taxonomic level, including family, genus and species.
• Foraging Strategy: Behavior exhibited during foraging and/or feeding.
• Periodicity: Time of day during which adolescents feed.
• Predators: Known predators of adolescents.
  
  
• Adults: Mature animals.
• Habitat: habitat utilized by adults.
• Diet: Prey items of adults. Major categories of prey are in bold, and all prey items are identified to the lowest possible taxonomic level, including family, genus and species.
• Foraging Strategy: Behavior exhibited during foraging and/or feeding.
• Periodicity: Time of day during which adults feed.
• Predators: Known predators of adults.
  
  
• Trophic Level: Trophic level for the species. Autotrophs (i.e. plankton, kelp) are level 1, herbivores are level 2, and succeeding levels are carnivores. This information is all derived from Cortes (1999).

Genetics

• Genetic Variance: In this section all information in a particular row comes from the same study, which is listed at the end of the section in the Source (Genetic Variance) column.
  
  
• Substocks: The division of a fish population into groups due to genetic differences.
• Haplotype Diversity (Geographic Area): Number and frequency of different haplotypes, and area where samples originated.
• Nucleotide Diversity (#): Average number of nucleotide differences per site between sequences.
• Mean Number of Alleles per Locus (SE): Mean number of gene variants at a particular locus.
• % Polymorphic Loci: The percentage of loci where the most common allele has a frequency of less than 0.95.
• Mean Heterozygosity: Mean proportion of genes at which the average individual is heterozygous, includes Expected (SE) and Observed (SE).
• Approach: Method(s) used to determine genetic variance.
• Effective Population Size: The size of an ideal population (i.e., one that meets all the Hardy-Weinberg assumptions) that would lose heterozygosity at a rate equal to that of the observed population.
• Source (Genetic Variance): Author and date of publication of the source for genetic variance information.

Behavior

• Behaviorial Interactions: Behavioral interactions with other (Interspecific) or the same (Intraspecific) species.
  
  
• Migration & Movement: Patterns of movement exhibited by a species.
  
  
• Tagging/Tracking Studies: Movement information derived from tagging and tracking studies.
• Movement Patterns: Movement information based on methods other than tagging and tracking studies, such as observational or catch data.
• Homing Ability (Home Range): Information on site fidelity and homing abililty.

Pathology

Types of diseases and parasites known to afflict a species.

• Parasites: Type and number of associated parasite species. The format followed in the LHDM is general taxomonic category followed by number of families and species within the larger grouping. For example: Cestoda (3 families, 4 spp.), which indicates that 3 families and 4 species of Cestodes are known to parasitize a particular species.
  
  
• Diseases: General overview of diseases affecting a species.