Video credit: Ahmed Shaheen (Egypt)
Review: Abdel Rahman El Gamal (Founder of the website and video channel)
This video was filmed in a marine hatchery in Vietnam
The video shows egg catheterization in Asian seabass (Lates calcarifer). Note that sampled fish has been slightly anesthetized in the shown ice box using ice. Determining the size (diameter) of eggs from female’s ovary by catheterization (biopsy) is being used as a criteria to determine the sexual maturation of females. Catheters could be rigid (made of glass or hard plastic) or flexible (made of polyethylene or vinyl). The leading edge of the catheter should be smooth or rounded to prevent any damage to sampled fish. Moreover, catheters should be of adequate size to match fish size and the genital opening (urogenital pore). Egg sampling this way should be done quickly and with minimum force to minimize physical injury to sampled fish. Improper catheterization may lead to the damage of sphincter muscles. If sphincter muscles got damaged, eggs at the posterior end of the ovary will water-hardened, and the plug is formed. Also, hemorrhage which could result of applying excessive force during introducing the catheter could lead to clotting and blocking of egg flow during ovulation.