Public aquariums provide access to invaluable information about ocean conservation for guests of all ages. However, many visitors are unaware that most marine ornamental species are collected from wild stocks. Little is known about the early life histories, and human impact on population dynamics, of many popular aquarium species. The Texas State Aquarium is one of many institutions working towards the collective goal of creating a comprehensive guide to egg identification. The Open-Source Marine Fish Egg Catalog (larvalcultureproject.org) is making it easier than ever to identify and sort mixed-species eggs for future larval rearing research. The present study aims to answer the questions: 1) what is spawning in our exhibits and when? and 2) what can aquarium spawning events and the eggs themselves tell us about the overall health of the animals in the collection?
A floating egg collector design will be utilized in the Living Coral Reef exhibit at the Texas State Aquarium to collect marine fish eggs once per month for 12 months. The number of viable and unviable eggs will be estimated by measuring the volume of eggs for each spawning event. Unviable eggs will be photographed and examined for morphological quality estimators including opacity, fragmenting of oil droplets, malformations in the early blastula stages, and the presence or absence of cytonemes assisting in cellular development. Samples of fertilized eggs will be individually photographed and preserved for genetic identification. Morphological data on viable eggs will include minimum and maximum egg, yolk, and oil droplet diameters, number and color of oil droplets, estimated age, or number of cells in the blastula, and the presence or absence of pigmentation and cytonemes within the developing egg. It is predicted that the number, quality, and species of eggs collected will vary seasonally throughout the year.
The results of this study will be applied towards the goals of understanding and prioritizing species vulnerable to overfishing, developing replicable techniques for egg collection and identification, and creating an animal health metric based on the quality and abundance of collected eggs. Subsequent research and development of larval rearing in public aquariums can further promote aquaculture and sustainable fisheries through new exhibits, public programming, and marketing to reduce man-made pressures on fisheries.