DNA barcoding of fish eggs in Scripps Coastal Reserve
Summary by Trey Stowe, Roy Little Fellow
In this 2018 study, Elena Duke, Alice Harada and Ronald Burton at Scripps Institution of Oceanography studied fish populations of two of Southern California's marine protected areas (MPA): the San Diego-Scripps Coastal State Marine Conservation Area (part of
Scripps Coastal Reserve) and the neighboring Matlahuayl State Marine Reserve. To monitor spawning activities within the MPA, egg samples were collected using nets dragged along in the water and then later identified to the species level using egg DNA. Using DNA analysis was necessary to identify the eggs as they are tiny (about a millimeter!), spread out into large areas, and in very high quantities. In addition to egg collections, historical data from previous monitoring of fish eggs and ocean temperature recordings were leveraged for the study.
This research found large variability year to year in fish egg quantities, with large declines in egg abundance during warmer years. On top of this, a shift in peak egg amounts was found, as peak egg abundance shifted to a month later than usual. Such findings are important to the scientific community, nature, and the general public as continued monitoring of our MPAs will allow us to better understand our marine habitats as well as the fish within them. This research also helps us better understand how human actions and natural environmental changes impact fish populations.
