Women In Natural Sciences Program Coordinator Kimberly Godfrey is participating in the National Oceanic and Atmospheric Administration’s Teacher at Sea program, which provides teachers hands-on research experience at sea. Godfrey is assisting a fisheries research cruise, which conducts biological and physical surveys to ensure sustainable fisheries and healthy marine habitats. She was aboard NOAA Ship Reuben Lasker while scientists conducted a Rockfish Recruitment and Ecosystem Assessment. You can learn more about this important scientific work by clicking here. She blogged about her experience at sea, and we are sharing excerpts from her posts here and below!
June 8, 2018
Rockfish […] are the primary focus of this survey. Therefore, I think they need a moment in the spotlight to themselves.
While this number may vary, NOAA has over 60 species of rockfish listed on the West Coast. They are an intriguing group of fish for many reasons. First, it is important to note that they are extremely significant to their food web because they are a prey species, but they are also important as a food and income source for humans. Species like the bocaccio rockfish and the yelloweye rockfish are species of concern due to over-fishing, and populations are slow to recover. That is enough reason to learn as much possible about these fish.
What we know about rockfish species is they can live for a long time. Many can live over 50 years; some can even live over 100 years of age! Their growth rate is relatively slow, and very few make it to adulthood because they are prey for other fish. During the first year (sometimes more depending on the species), they spend much of their time in the pelagic realm (open water). If they live long enough, they can grow to a size that allows them to settle in the benthic zone (ocean floor). For many species, 60 mm is a large enough size to settle. This is what the term “recruitment” refers to. Once rockfish settle out of the pelagic zone, they have a higher chance of reaching reproductive maturity.
NOAA Fisheries has been surveying the West Coast for rockfish since 1983. They first started in a smaller region from Monterey Bay to Point Reyes, CA. The survey area expanded in 2004, and by 2013 it covered the entire coast of California. The success of the local ecosystem and the commercial fisheries depend on healthy fish populations. The survey tries to collect at least 100 specimens per species of rockfish and take them back to the lab (on land).
Back at the lab the species identifications are determined. Many rockfish are difficult to identify to species at this life history stage without using a microscope. In addition, their size is recorded and tissue samples taken for genetic studies.
Then, on select species, otoliths are removed to age the specimens. The otolith is an ear bone. In fish, the ear bone deposits layers of bone in rings. It happens daily and these daily rings can be counted using a microscope to learn how old the fish is. These ages are used by scientists not only to learn how old the fish are, but also they can compare this information to the size data collected and estimate the expected size of a fish at any given age.