3 Horodysky Throws Light on Fish Vision Andrij Horodysky’s research can be The research is part of an emerg- Horodysky also benefits summed up in a simple saying—what ing field called “visual ecology” that from collaborations with Char- you see is what you get. promises to throw new light on animal ter captains like Steve Wray, Horodysky, a VIMS graduate behavior and the interactions between who provide him with the fish student working with faculty members predators and prey. Horodysky and his he needs for his experiments. Drs. Rich Brill, Rob Latour, and Jack advisors are pioneers in applying this Horodysky’s preliminary Musick, is using electroretinography—a field to Bay fishes. results provide basic insight technique first developed for studying The researchers are focusing their into how Bay fishes see the human vision—to explore how fishes initial studies on recreationally impor- world. The results show that see the underwater world of Chesapeake tant Bay species such as striped bass, some species, like striped bass, Bay. weakfish, croaker, and drum. This re- are adapted to see large, swiftly Brill, an internationally recognized flects the source of their funding, which moving prey in daylight. Oth- fish physiologist who heads NOAA’s comes from the Recreational Fishing ers, like weakfish, are adapted Cooperative Marine Education and Advisory Board of the Virginia Marine to see small, sluggish prey at Research (CMER) program at VIMS, Resources Commission. The Board uses night. has recently turned his attention to the money from Virginia’s saltwater fishing He is also comparing the sensory world of fish and other marine license to fund projects that improve the types of prey that fishes are organisms. Commonwealth’s recreational fisheries. adapted to see with the prey items that are actually in their stomachs—with some surpris- ing results that could hold VIMS graduate student Andrij Horodysky (L) and W&M Bestows Honorary Doctorate important implications for faculty advisor Dr. Rich Brill (R) are studying the fisheries management in coastal “visual ecology” of popular recreational fishes from on Van Engel waters. Chesapeake Bay. Horodysky’s red-light head lamp VIMS Professor Emeritus Willard led the way with cutting-edge research in Electroretinography in- allows him to work in the dark without affecting his A. Van Engel received an honorary doc- the Chesapeake Bay and was a pioneer volves exposing the eye of an experiments. torate of science from W&M Chancellor in many marine science research areas, anaesthetized fish to all the Sandra Day O’Connor during com- including his seminal work on blue crabs colors of the rainbow and more—from fish range from around 25 in swordfish, mencement ceremonies at The College and the blue-crab fishery. ultraviolet to infrared—and then using which require a “slow shutter speed” of William and Mary in May. Van Engel is also credited with first electrodes to record which wavelengths to detect prey in the deep, dark waters Van Engel is credited with being recognizing the need for keeping dupli- elicit a response on the fish’s retina. where they spend their days, to around one of the individuals responsible for cates and reprints of scientific papers and Horodysky conducts these tests night 55 for mahi-mahi, which often hunt at the creation of the Virginia Institute of reports in one centralized location—an and day to account for rhythmic changes the surface in the sunlit tropics. Marine Science, when in the mid-1940s effort that grew to become the VIMS in the structure of the fish’s eye. Horodysky’s research shows that he and colleagues at the Virginia Fisher- Library. He has also been a strong sup- Even though Horodysky keeps his striped bass are most sensitive dur- ies Laboratory developed the scientific porter of the college and his generosity fishes in a dark laboratory, the rod and ing daylight hours to a wide range of community that later became VIMS. has allowed for the Van Engel Gradu- cone cells in the fishes’ eyes still shift colors from blue to red, with a peak at Van Engel conducted research and ate Fellowship and VIMS Library to position in concert with sunrise and chartreuse. They have a flicker fusion taught at VIMS until 1985 when he re- continue in perpetuity. sunset. The color-sensitive cone cells frequency of around 50, relatively fast for tired at age 70. Upon retirement, he had In 2003, VIMS awarded Van Engel move toward the surface of the retina a fish, which allows them to track large, dedicated 39 years of his life to VIMS with its first ever Lifetime Achievement during daylight hours, and retreat to quick-moving prey like menhaden. and its School of Marine Science. Award for his outstanding contributions make room for the contrast-sensitive rod Compared to striped bass, weakfish Van Engel, also known as “Van,” to the state and the college. cells at night. This “circadian rhythm” have slow vision (around 25 cycles per changes with the seasons, which makes second) and are more sensitive to con- for some late nights for Horodysky dur- trast than color. This allows them to see ing summer, when he is not able to start best under dim conditions, just right for his dim-light experiments until 8 or 9 in detecting the small fish and shrimp that the evening. prowl the nighttime Bay. They also have “The end result of these experi- the unusual ability to see in ultraviolet. ments,” says Horodysky, “is the ability Seeing in ultraviolet is a dangerous to unambiguously ask the retina whether proposition, says Brill, as UV light is it can see a particular color, and whether very damaging to cells and even DNA. it can resolve the color in bright or dim Using UV light allows weakfish to dis- light.” tinguish between dark and light objects He also tests the fish’s “flicker fusion in dim conditions, but forces them, like frequency,” essentially the shutter speed bats and owls, to avoid bright sunlight. of its eye. Humans have relatively “fast” “There’s no such thing as a free vision and can discern the flickering of lunch,” says Brill. “You can have a re- a light or image at up to 60 cycles per ally good UV-sensitive eye, but then you second (that’s why TV screens, fluo- have to work at night.” Dr. Willard van Engel receives his honorary doctorate from William and Mary rescent lights, and computer monitors “Even though these two predators Chancellor and former U.S. Supreme Court associate justice Sandra Day O’Connor are designed to flicker at a rate faster may swim side-by-side, they exist in dif- during commencement ceremonies at the College on May 14th. Photo by Steve than this threshold). Values in marine ferent visual worlds,” adds Horodysky. Salpukas. Continued on page 7 7 Wetlands Workshop Promotes Informed Resource Management Scientists from VIMS’ Center buffers, marshes, intertidal flats, and the policy, technical information applied at To view workshop presentations for Coastal Resources Management adjacent shallow-water environment,” the local level leads to more informed and photos, go to ccrm.vims.edu/semi- (CCRM) discussed shoreline and says program director David O’Brien. and ecologically favorable resource man- nar2006.htm wetland issues with members of local “They also learn to recognize that the agement decisions,” says O’Brien. wetland boards and other resource man- impacts of shoreline protection projects agers during a recent Tidal Wetlands can’t always be easily mitigated.” Workshop on the William and Mary The conference included a comput- campus. erized audience response system that The one-day conference, “Avoid- allowed the 116 participants to cast votes Minimize-Compensate Through In- from their seats on relevant wetlands and tegrated Shoreline Management,” shoreline-related questions. Evaluation provided up-to-date information on comments show that participants en- shoreline protection, management, and joyed the apparatus: “I liked the system policy issues—the three core areas of the because it helped me gauge how much I CCRM Wetlands Advisory Program. was retaining and understanding,” said The workshop focused on promoting one participant. “I enjoyed seeing what an integrated, cross-jurisdictional ap- the other wetlands boards think,” noted proach to shoreline management along another. with a discussion of living-shoreline The Wetlands Advisory Program treatments. at VIMS has been providing wetlands “Participants in our outreach pro- and shoreline information to the public grams develop an increased awareness since the late 1960s. “In supporting the of the ecologic functions of riparian Commonwealth’s no-net-loss wetland David O’Brien addresses workshop participants.

Fish Vision visual predators. It’s the number they continued from page 3 can see. Is there a visual issue, with the Bay being turbid, being murky? If you “You’ve got two animals that are com- can’t see very far, how is that affecting peting for the same food. How do they your ability to feed? These are larger do it? Stripers use color to see and feed questions we can begin to chip away at during the day. Weakfish use contrast once we get our baseline data. We can’t sensitivity to see at night.” start to answer these questions until we “What these fishes have done is know the limits of the eye.” divvy up the visual world,” says Brill. In the meantime, Brill and Horo- For the most part, study of stomach dysky plan to expand their research contents by VIMS researchers confirms to other popular recreational fish like what Horodysky’s vision research pre- summer flounder and cobia, and also to dicts. Work by Dr. Rob Latour shows the forage fish—most notably menha- that the stomachs of weakfish are largely den—that so many recreational species empty during the day, and then quickly depend on for food. begin to fill with small fishes and shrimp For Virginia’s anglers, the most im- as evening falls. Work by graduate stu- portant question for Horodysky might be dent Kathleen McNamee shows that VIMS graduate student Andrij Horodysky monitors the progress of a vision experiment how a better understanding of fish vision striped bass have full stomachs during using an Atlantic croaker (Micropogonias undulatus). can give them better luck on the water. daylight hours, but that the stomachs “I can’t guarantee that anyone who uses gradually empty through the night. oyster have dramatically reduced the of the Bay changing. Our argument is these data is going to catch more fish,” One intriguing aspect of Horo- clarity of Bay waters. that over evolutionary time these fish responds Horodysky. “But they will be dysky’s research is the disparity he’s The world of Chesapeake Bay have made certain visual choices, then able to make more informed choices.” found between the prey items that stripers was once bright and colorful. suddenly find themselves in a visual Horodysky, himself a fly-tier and striped bass are adapted to see—large, Anecdotal evidence from Captain John environment they didn’t evolve in.” avid angler, notes that his color research fast-moving fish like menhaden—and Smith and others suggests that visibility This visual mismatch could have does confirm at least one common saying the items that actually occur in their in the Bay once measured in the tens of important implications for fisheries that Bay anglers use when selecting a stomachs—mostly small crustaceans like feet. Even a century ago, Bay waters managers, who traditionally make man- lure for striped bass: “If it ain’t char- juvenile blue crabs and mysid shrimp. were clear enough to allow plant growth agement decisions based on the relative treuse, it ain’t no use.” Horodysky and his faculty advisors at depths of more than nine feet. Now abundance of predator and prey—the “Nothing in the wild is ever char- hypothesize that striped bass are living sunlight penetrates to only half that number of striped bass or menhaden treuse,” says Horodysky, “but the color in a visual world very different from the depth. netted per unit area. is right smack dab in the middle of a one evolution prepared them for. That’s “Chesapeake Bay used to be very “What we’re getting at,” says Horo- striper’s visual range. They can see it because human activities in the Bay clear,” says Brill. “Now we’ve made dysky, “is that it isn’t the number of prey really well.” watershed and the demise of the native it mucky. So we see the visual ecology per meter that’s most important to these