Telescope Shiners' Whole Ovaries, In A Time Series

We've been working on describing the reproductive status of telescope shiner ovaries in the last several weeks. This takes two connected forms: describing the maturity of the ovary, and describing the developmental stages of the oocytes inside the ovary. We've made photographs of ovaries using a digital dissecting miscroscope, and then torn apart the ovary to separate the developing eggs which are then photographed in groups of about 50 mounted on microscope slides. The whole ovary images allow us to characterize their status at our leisure and double-check our assessments later, and the egg photos allow us to count, describe and measure the eggs using the digital software Motic 1.2. Eggs are stored in 10% buffered formaldehyde for further examination.

Below is a series of three whole (or almost whole...) ovaries from individuals collected from Hurricane Creek at the Walls of Jericho in March, April and May. All were photographed at X10 magnification, and the image area is about 18 mm wide. The March ovary has visible oocytes that are in the early stages of vitellogenesis, being loaded with phospholipoproteins. A typical oocyte in this ovary is about 0.7 mm in diameter. Both lobes of the ovary are visible, with the oviduct (exit) visible in the lower left.

The April ovary is larger, with the creamy yellow color indicating near-maturation. The largest yellowish oocytes are about 1.1 mm in diameter and are in late vitellogenesis, closer to being ripe. Less mature developmental stages are also present.

The May ovary is bigger still, with only one of the lobes mostly visible in this photo. The ovary is nearly transparent and the outer membrane is stretched tightly. Fully ripe oocytes are visible in the darker reddish area which is close to the oviduct. These largest oocytes are 1.4 - 1.5 mm in diameter. The full range of developing oocytes is present in this ovary.

March ovary:

April ovary:
May ovary: