June 29, 2017
Contact: Heather Soulen
Digital Media As a Research Tool
A camera just isn’t a camera anymore. Yes, cameras still document our exciting times in interesting places with friends and family, but the digital landscape has definitely changed. Today we have cameras and smartphones with high resolution video and their ease of use, storage capacity, and distribution pathways are what makes them such a valuable research tool for scientists.
For decades scientists have been using camera and video systems to generate data used to answer all kinds of research questions. Here are just a few examples of how and why NEFSC scientists use cameras to answer big research questions. It’s said photos speak a thousand words. For scientists, they can create a thousand data points with just a click of a button.Euphausiids, or krill, are small shrimp-like crustaceans that are consumed by many baleen whales. Photo credit: NOAA Fisheries/Elisabeth Broughton. Click image to enlarge
Capturing Plankton's Good Side
Elisabeth Broughton, physical oceanography technician at the Woods Hole Laboratory, uses an underwater video microscope system called a video plankton recorder (VPR) that takes pictures of plankton drifting in the ocean. The VPR is towed at targeted depths behind a research vessel to capture interesting oceanographic or biologically dynamic layers seen on the active acoustics. While the VPR takes 15 to 20 photos per second, oceanographic data like temperature, salinity and chlorophyll are also collected. Photos are then used in conjunction with a couple of software algorithms that ultimately identify all of the photographed zooplankton into special groupings like copepods, fish larvae, and jellyfish. The beauty of this VPR system is that it quickly provides NEFSC scientists with plankton and oceanographic data that can be translated into distributional patterns of plankton. The VPR system also provides data on delicate organisms like jellyfish, siphonophores and salps as well as insights on species’ interactions and that wouldn’t normally be detected with net sampling methods. Members of the Protected Species Branch are working in collaboration with Elisabeth and others in the Oceans and Climate Branch to compare plankton distribution patterns with whale migration and distribution patterns to help with the protection and management of threatened and endangered whale species.Fish eggs are photographed using a camera and microscope system and photos are processed to generate counts and length and width data. Numbers in photo represent egg number. Photo credit: NOAA Fisheries/David Richardson. Click image to enlarge
How to Measure a Fish Egg
Scientists at the Narragansett Laboratory use a camera and microscope system with special computer software, parts of which were developed by NEFSC scientists, to identify and measure fish eggs from ichthyoplankton samples collected throughout the year. Ichthyoplankton are the early stages of fish - eggs and larvae - which drift in the ocean at the mercy of winds and currents. Data from these early life stages are vital components of stock assessments, helping to estimate the number of spawning adults. These data are also used to study changes in the distribution and abundance of fish in relation to climate and ecosystem change.GoPro video help scientists at the Milford Laboratory understand how fish like this tautog might use aquaculture gear like this oyster cage as habitat. Photo credit: NOAA Fisheries/Paul Clark. Click image to enlarge
Tracking Fish Behavior
Scientists at the Milford Lab are studying if and how aquaculture gear might function like naturally occurring rock reef habitats to provide commercially and recreationally important fish with food, shelter and other ecosystem services. To do this, they’ve attached GoPro cameras to their oyster cages. The cameras will record video to help describe encounters and interactions between the gear and fish. For comparison, the research team has also collected encounter and interaction video at rock reef habitats. Another research question they’re interested in is how cage density (number of cages in a given area) might affect things like fish abundance and diversity. The team will review video and record things like species, abundance, and behavior. Not only will this study help provide information about aquaculture gear as habitat, but it may also help inform regulatory and permitting processes for marine and estuarine aquaculture.The wave-like movements of cilia can be seen in this video recorded by the team. Credit: NOAA Fisheries/Melissa Krisak
Watching Oysters Drop a Beat
The Eastern oyster (Crassostrea virginica) is a filter-feeding bivalve, meaning that they feed by moving water over their gills through the beating of small hair-like structures called cilia. Elevated levels of dissolved carbon dioxide in marine and estuarine environments may affect the ability of cilia to beat, which could affect things like feeding, health, growth, and reproduction. Oyster cilia are about one quarter of the length of a human eyelash, so Shannon Meseck and others at the Milford Laboratory use a camera and microscope system with strobing illumination to record the beat frequency of oyster cilia. The research team are comparing ciliary beats of oysters reared in water with high levels of dissolved carbon dioxide to oysters reared in water with today’s level of dissolved carbon dioxide. Because the Eastern oyster is an economically and ecologically important species along the East Coast of North America, understanding its physiological response to factors related to ocean acidification is important for cultivating healthy and productive marine and estuarine ecosystems.This subsample of ovarian tissue contains several different development stages of oocytes. The team is only interested in counting the larger translucent oocytes that are ready for spawning. Photo credit: NOAA Fisheries/Emilee Towle. Click image to enlarge
Summer flounder (Paralichthys dentatus) are found in inshore and offshore waters along the Atlantic Coast from Nova Scotia, Canada to the eastern coast of Florida and are one of the most sought after commercial and recreational fish. Because of this, knowing when they spawn and how large each spawning event will be is important for maintaining a healthy and resilient summer flounder fishery for all to enjoy. To do this, Emilee Towle, fisheries biological technician, and others in the Population Biology Branch uses a camera and microscope system with image analysis software to quickly and accurately count special cells called hydrated oocytes. To do this the research team collects a small representative subsample of ovary tissue, places it under their microscope, and photographs the tissue (image right). Because hydrated oocytes are large and translucent compared to other underdeveloped oocytes, using specific functions within the image analysis software quickly marks and counts hydrated oocytes. After quality checking the results, data are then used to estimate batch fecundity, the number of eggs available to be fertilized, for each summer flounder and later for the whole stock. After including additional data like fish length, they’ve learned that larger fish produce larger batch sizes. They’ve also learned that the largest batches occur at the beginning of the spawning season. From a management standpoint, it appears that it’s important to protect larger summer flounder since they produce more eggs during the spawning season.Elevated levels of dissolved carbon dioxide may affect the shell development and growth of larval bivalves like surfclams. Photo credit: NOAA Fisheries/Cathy Kuropat. Click image to enlarge
A Surfclam’s Growth Chart
As carbon dioxide levels are predicted to rise in marine and estuarine environments, how will that affect marine animals? Last year, scientists at the Milford Laboratory decided to test that question with larval surfclams. Surfclams are an economically and ecologically important bivalve in the Northeast and understanding how they might be affected by elevated levels of dissolved carbon dioxide at various points in their development is important for a healthy and sustainable surfclam fishery. Using a camera and microscope system, the research team photographed larval surfclams at roughly 48 hours old and continued to photograph them every two to three days during the experiment. With the help of image analysis software, the team tracked growth and survival over time under three different carbon dioxide levels. Because larval surfclams are so tiny, about half the width of pencil lead, using a camera and microscope system was crucial for measuring and documenting growth and survival. Not only do these data contribute to the larger body of knowledge surrounding the effects of ocean acidification on bivalves, but they also help the team understand how surfclams respond to environmental change, and how best to plan for and manage for future change.
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