Standardized Maturity Stages for Live-Bearing Sharks

Determining the maturity state of sharks in the field is difficult.  The following summary is offered to help standardize observations and reportage of gonadal maturity in ovoviviparous and viviparous sharks.  Once familiar with the stage categories proposed here, maturity state of sharks examined in the field can be determined accurately and scored quickly.

Males

Juvenile claspers undeveloped sticks gonads tiny, thread-like, and whitish sperm ducts straight
Subadult claspers formed but soft, flexible testes enlarged sperm ducts meandering

Adult claspers fully formed and stiff testes well rounded, reddish, and filled with flowing sperm sperm ducts tightly coiled
Active glans of claspers often dilated and swollen sperm flowing from cloacal papilla under pressure applied to belly and/or present in clasper grooves

Females

Ovarian Stages

Juvenile ovaries small, gelatinous or granulated eggs not yet differentiated or evenly small and granular uteri thread-shaped
Ripening ovaries enlarged, walls transparent eggs differentiated to various sizes uteri thread-shaped
Ripe ovaries large, well rounded eggs enlarged, all about the same size so that they can be counted and measured easily

Uterine Stages

Developing uteri well filled and rounded with unsegmented yolk content
Differentiating uteri well filled and rounded with segmented content of yolk balls embryos small, unpigmented, and with large yolk sacs, but can be counted
Expecting embryos fully formed and pigmented, yolk sacs obviously reduced embryos can be counted and measured easily
Postnatal ovaries at resting stage, similar to Developing stage uteri empty but still widened considerably in comparison with Developing and Differentiating stages