Meeting Abstract
The surfperches (Embiotocidae) are marine coastal fishes distributed along the eastern Pacific Ocean from Alaska to central Baja California. Surfperches are ecologically diverse and live in a variety of habitats including sandy bottoms, rocky reefs, kelp forests, and seagrass beds. Surfperches are among the approximately 500 fishes that exhibit internal fertilization and bear live young. During copulation, males utilize external copulatory structures (e.g., genital papilla, intromittent organs) to transfer spermatozeugmata, large bundles of sperm into the female reproductive tract. Surfperch copulatory structures have not been fully investigated and are not well understood. We hypothesized that surfperch male copulatory structure complexity would vary based on the primary habitat utilized by the species. We used paraffin histological techniques and scanning electron microscopy (SEM) to examine copulatory and associated reproductive structures in three surfperch species occupying different habitats. Walleye surfperch (Hyperprosopon argenteum) inhabit sandy bottoms and had a genital papilla anterior to the anal fin, which appears bulbous with posteriorly located paired fleshy plates. Shiner perch (Cymatogaster aggregata) are typically found in eelgrass beds and had a genital papilla and paired intromittent organs located on both sides of the anterior portion of the anal fin, whereas black perch (Embiotoca jacksoni) that live in rocky reefs only had paired intromittent organs located anteriorly on both sides of the anal fin. We have identified several differences in the complexity of surfperch external reproductive anatomy. Morphological structures have previously been directly linked with niche partitioning in surfperches, however our research is the first to investigate copulatory structures and diverse environments.
