What Can Anglers Learn from NOAA's Smart Buoys
If you pay attention to the longterm trends that the data from the Bay's ten NOAA smart buoys produce, you'll earn insight into what's happening in your angling waters. [June 2013]
By John Page Williams
Back in the winter of 2007-08, the Potomac River "smart buoy" operated by the National Oceanic and Atmospheric Administration (NOAA) went walkabout for a couple of days. The truth is that its mooring chain broke under the constant strain of holding it in place in the exposed waters just inside Point Lookout. NOAA was able to track the buoy thanks to the devices's constant reporting of its latitude and longitude. It drifted from the mouth of the river down into the Bay, where a crew from Smith Point Sea Rescue in Reedville, Va., got a line on it and towed it in. It has remained faithfully on station ever since. The buoy's trip provided two benefits to the NOAA office. One was a clear suggestion to use stronger chain; the other was a clear indication of how important the Potomac buoy is to the fishing community in that part of the Bay. On TidalFish.com, the "Northern Neck Angler" bulletin board lit up with questions of why the buoy had gone quiet. One angler teasingly accused a fellow angler of breaking it by calling it too often, and he threatened to give his friend a toolbox and maroon him on the buoy until he figured out how to fix it.
This Chesapeake Bay Interpretive Buoy System (CBIBS) now numbers ten buoys, six of them in the open Bay, stretching from the Virginia Capes (First Landing) to the mouth of the Susquehanna, and four of them in rivers. Offering round-the-clock access by telephone (1-877-BUOYBAY), web (www.buoybay.noaa.gov), and now smart phone app (search for CBIBS in your app store), these buoys have obvious value to a wide range of recreational and commercial boaters and mariners. They give near-real-time readings (ten minute updates on most measurements) of wind, waves, current direction and velocity, water temperature, air temperature and barometric pressure.
Water temperature graph from the Annapolis buoy
CBIBS is the brain child of Dr. Doug Wilson, a career NOAA oceanographer who, though now retired, continues to oversee the system. Though there were already many valuable observation buoys in the Bay, operated by federal and state agencies and research institutions, his concept was for a permanent system of continuous scientific monitoring, including weather. A racing sailor himself, Wilson believed that CBIBS would add additional value by informing a wide swath of the general public. Verizon agreed to synthesize the data and transmit it for telephone and web applications.
The first three CBIBS three buoys went into the water in 2007-one off Jamestown, Va., about 20 miles up the James River from Hampton Roads, one in the mouth of the Potomac and one in the Bay off the mouth of the Patapsco. Seven more have been built and deployed over the intervening six years.
From a purely fishing standpoint, the buoys are informational gold mines. While up-to-date weather observations of course have great value to anglers, several of the scientific observations can provide valuable clues about where to find fish. Water temperature, salinity and turbidity (water clarity, or lack of it) are obvious, but dissolved oxygen and chlorophyll a (mostly a measure of algae in the water) also play important roles in fish habitat. Both daily observations and long-term trends from the buoys can be valuable.
Here are several suggestions for using daily observations. One is to look at buoys both above and below where your boat is based or where you plan to launch. In some seasons, blending water temperature and turbidity with weather conditions can provide clues about which way to run to find fish. In addition, the measurements may help you fit strategy to conditions: at what depth will you find the fish, whether they will be active or not, and whether bait or lures will be more effective.
The Gooses Reef buoy deserves special mention because it holds a unique feature that NOAA would like eventually to incorporate into all of the others: a bottom sensor with a modem that sends observations on dissolved oxygen, salinity, temperature, turbidity, current and chlorophyll a to the buoy itself and then to the public. This buoy, set in the mid-Bay off the mouth of the Little Choptank, is anchored over a large restoration oyster reef funded by Dominion Resources.
The great value of the bottom sensor is the way it shows us how the Chesapeake stratifies, with the saltier, cooler, denser but too often oxygen-depleted water at the bottom. In summer, it gives us an idea of whether fish will stay in deep water or not. Even anglers from the lower Bay will find the Gooses Reef buoy readings useful because they show whether the difference in water conditions between surface and bottom is strong or not. From there it's possible to estimate in a specific location the depth where the change is sharpest by looking for a thermocline (temperature break) or halocline (salinity break) on the boat's sonar screen. Fish like rock will often sit just above that break, and the sonar will display them as well. At this point, there's not enough funding in the system to place those sensors on the other buoys, but we can hope.
For long-term trends at all of the buoy locations, the CBIBS website offers a graphing tool. Captain Andrew Turner, a former Solomons, Md., charter boat skipper who now works as a Fisheries Specialist at the NOAA Chesapeake Bay Office, has worked out several ways for anglers to use the graphing tool to study trends. One is a January-to-April water temperature graph for the spring trophy rockfish seasons at specific buoys. Turner has found that the quality of the fishing from year to year correlates well with the springtime rise in water temperature. Thus the late April rise in 2011 slowed the influx of fish till the season-opening dates in Maryland and Virginia, while early warm weather in 2012 sent most of the big fish back out into the Atlantic before the openers. As I write this column, two days before Maryland's opening day, the warm water has come late and fish appear to be pouring up the Chesapeake's main stem and the rivers; by the time you read it, we'll all know if the correlation has held again in 2013.
Two more of Turner's graphs offer wisdom for summer trip planning. It's useful to check summer and early fall dissolved oxygen records in multiple years for multiple locations to see where in the Bay conditions are best. Even with only surface readings (plus bottom information from the Gooses Reef), it's possible to make judgments. The same analysis can be useful for spring and summer summertime rockfish and bottom fishing. For example, if you head to the CBIBS website (buoybay.noaa.gov) and click on "graphing" you can create graphs to learn about summer rockfishing by comparing graphs for the period June 1-October 31, 2012 for the Annapolis, Gooses Reef and Potomac buoys. Then you'll be able to discern which location has the healthiest dissolved oxygen levels.
Dissolved oxygen at the Annapolis buoy
Here is a short-term warning system that we have seen the last several years. Watch chlorophyll a and its relationship to dissolved oxygen. If you see the chlorophyll go high in warm weather, graph it for several days and you'll see the oxygen oscillate violently. What's happening is that duringthe day, chlorophyll is doing its job, absorbing the sun's energy to split carbon dioxide molecules, converting them to food in the cells of algae that are drifting in the upper water column while giving off oxygen. They use some of that oxygen in their own cell processes but produce a surplus.
Whenever a bloom occurs, the quadrillions of cells produce a huge surplus, which can drive the daytime dissolved oxygen to super saturated levels. At night, though, the algae cells have no light to drive photosynthesis, but they are still using up oxygen. With so many living cells in the water, the dissolved oxygen level crashes, generally reaching its lowest point around dawn. As the sun rises, photosynthesis begins again, and the dissolved oxygen goes back up. The effect is alternating feast and famine. Obviously, when a bloom like this is in the water, evening fishing will be better than early morning.
This effect has been most noticeable on the Upper Bay buoys, specifically Patapsco and Annapolis, but it can happen anywhere. Despite the high oxygen during the day, the nightly crash tends to drive fish (and crabs) away. A bloom will last for two to three days, after which the cells will die and sink to the bottom, where aerobic (oxygenusing) bacteria will decay them, basically sucking up most of the oxygen in the water column. Then it's not a feast-and-famine cycle; it's just roundthe- clock oxygen starvation.
If you see this pattern shaping up, find somewhere else to fish for a couple of days, ideally where there is plenty of fetch for wind to roil the water and re-oxygenate at least the upper layers. Or pray for a hard rain, which is very effective in re oxygenating the water. (And yes, the algae blooms that cause this condition are driven by nitrogen and phosphorus pollution, another good reason for Bay anglers to support cleanup programs.)
This sort of analysis of buoy observations has got Andrew Turner talking to anglers and charter skippers all over the Chesapeake, so it's a good bet that some other uses for buoy data will turn up this season. As they do, we'll pass them along to readers of Angler's Almanac. If you come up with one, please e-mail it to anglers@ChesapeakeBoating.net.
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