Author: mcguire.399

Like to catch Walleye, but are concerned about overfishing?

Fear no more! Aquaculture is here to save the day.

Aquaculture is the world’s fastest growing food production industry. Many species are of aquaculture interest, including Walleye (Sander vitreus), Yellow Perch (Perca flavescens), Rainbow Trout (Oncorhynchus mykiss) and many more. Aquaculture is defined as the raising of aquatic organisms for food. The industry of aquaculture often rears sport fishes—such as the Walleye—for the purposes of stocking them. Once they are stocked, anglers catch them and eat them. Walleyes are now one of the most sought-after sport fishes, and they are found in 32 percent of freshwater ecosystems in North America. The North Central Aquaculture Center previously identified Walleye as one of the most promising aquaculture species.

Great Lakes populations of Walleye have been overfished in the past, resulting in population declines in areas of the Great Lakes. States have implemented strategies to prevent population decline, such as habitat protection as well as walleye rearing and stocking. Rearing and stocking Walleye can help keep the population at a healthy level and keep Walleye in the Great Lakes for many years to come. Walleye can be stocked as juveniles; from there they will continue to grow in the wild until they are of catching size. The U.S Fish and Wildlife service has stated that climate change has begun to affect Walleye habitat distribution. The displacement of Walleye by warm water species may change their range and population. The culturing of Walleye for stocking purposes may help to mitigate this issue.

So how is it done?

Walleye are often bred in aquaculture facilities and kept there until they are of stocking size. They are often fed commercially available foods. Typically, they are kept in large tanks with colder water, in order to best mimic their natural habitat. Tank size will vary based on the aquaculture facility or lab. In Dr. Dabrowski’s lab on the OSU campus, we keep our juvenile Walleye in 400L tanks. Here is a photo showing where they are kept!

References:

https://www.fws.gov/fisheries/freshwater-fish-of-america/walleye.html#:~:text=Great%20Lakes%20walleye%20populations%20have,the%20Great%20Lakes%20drainage%20basin.&text=Recent%20climate%20changes%20may%20be,sunfish%2C%20largemouth%20and%20smallmouth%20bass.

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1008&context=ncrac_whitepapers

https://www.ncrac.org/files/page/files/Chapter9.pdf

 

Zebrafish are a small tropical species in the Cyprinidae family, and they are native to regions in South Africa.

Have you ever wondered why Zebrafish are often used in medical research?

It turns out that Zebrafish are a model organism, and share a lot of similarities to humans! We actually share 70% of our genes with Zebrafish. They have a lot of the same physical characteristics as us, such as a heart, spinal cord, eyes, kidneys…the list goes on. Zebrafish have also been useful for studying human diseases. Since Zebrafish share a lot of the same characteristics, changes in human organs as a result of disease will also appear in Zebrafish organs as well. They have also been used for toxicology studies, such as how certain substances or drugs affect their physiology.

Zebrafish are useful for understanding areas of ecology as well. Lots of genetic experiments have been performed with Zebrafish. Since they are a model species, methodology used in genetic experiments can also be applied to other species. A lot of people may wonder about the other benefits of Zebrafish, aside from them being a model species. First, they are quite small. This makes them efficient to keep in research labs, especially where space is often limited. They are quite easy to handle, hardy, and are easy to provide proper husbandry for. Also, females are quite fecund and will produce many eggs per spawning event. This is useful for when many eggs or embryos may be needed to run an experiments. Unlike some fish, Zebrafish in captivity do not have a spawning season. Spawning can be induced anytime, which is very useful for experimentation and research purposes. Lastly, in vitro fertilization (fertilization outside the body) can be done with Zebrafish, making it very easy to control fertilization and study development.

Here’s a photo of a Zebrafish:

Here’s a photo of a Zebrafish embryo developing under the microscope (this is at the 8 cell stage!)

References:

https://irp.nih.gov/blog/post/2016/08/why-use-zebrafish-to-study-human-diseases

https://academic.oup.com/mbe/article/32/3/635/976822?login=true