North American Journal of Fisheries Management 30:1365–1369, 2010 Ó Copyright by the American Fisheries Society 2010 DOI: 10.1577/M09-201.1
[Management Brief]
A Digital Underwater Video Camera System for Aquatic Research in Regulated Rivers BENJAMIN M. MARTIN Alabama Cooperative Fish and Wildlife Research Unit, 3301 School of Forestry and Wildlife Sciences, Auburn University, Auburn, Alabama 36849, USA
ELISE R. IRWIN* U.S. Geological Survey, Alabama Cooperative Fish and Wildlife Research Unit, 3301 School of Forestry and Wildlife Sciences, Auburn University, Auburn, Alabama 36849, USA Abstract.—We designed a digital underwater video camera system to monitor nesting centrarchid behavior in the Tallapoosa River, Alabama, 20 km below a peaking hydropower dam with a highly variable flow regime. Major components of the system included a digital video recorder, multiple underwater cameras, and specially fabricated substrate stakes. The innovative design of the substrate stakes allowed us to effectively observe nesting redbreast sunfish Lepomis auritus in a highly regulated river. Substrate stakes, which were constructed for the specific substratum complex (i.e., sand, gravel, and cobble) identified at our study site, were able to withstand a discharge level of approximately 300 m3/s and allowed us to simultaneously record 10 active nests before and during water releases from the dam. We believe our technique will be valuable for other researchers that work in regulated rivers to quantify behavior of aquatic fauna in response to a discharge disturbance.
Unobtrusive observations of fish by use of underwater video cameras (UVCs) have been useful for obtaining information necessary for conservation and management decisions (Hinch and Collins 1991; Bettoli and Clark 1992; Cooke et al. 2003; Steinhart et al. 2004; Carbines and Cole 2008). Many biologists have modified UVCs or constructed add-ons that are tailored for their specific research objectives (Groves and Garcia 1998; Cooke and Bunt 2004; Chidami et al. 2007; Myrick 2009). We designed a UVC system to use on the highly regulated Tallapoosa River, Alabama, below Harris Dam. Discharge at the study site often increased in late afternoon and peaked overnight. Our major challenge in developing this system was determining how to secure cameras on the periphery of redbreast sunfish Lepomis auritus nests to allow recording of reproductive behavior before and leading up to peak discharge (.300 m3/s) without loss of or damage to equipment. This was made possible with a creative substrate stake design to which cameras could *Corresponding author:
[email protected] Received December 3, 2009; accepted August 8, 2010 Published online November 8, 2010
be harnessed. In this brief, we describe our digital UVC system design, substrate stake fabrication, and deployment method. Methods System design.—The UVC system consisted of a 16channel digital video recorder (DVR; Table 1), 10 digital UVCs (Table 1) with variable-length underwater cables, a video monitor, two deep-cycle batteries (DVR and video monitor; cameras), and a 400-W inverter to convert current for the DVR and video monitor (Figure 1; Table 2). We used a DC battery to operate the DVR and video monitor so as to minimize noise disturbance that might affect fish behavior during our study. A CMC Tech, Inc. (Houston, Texas), DVR unit (Figure 1) was used for video capture, which allowed simultaneous recording of up to 16 digital cameras; however, for our purpose, only 10 were required. Black-and-white cameras (12 V; SuperMini Model SM-50-C; SeaView, Tampa, Florida) were purchased alone (i.e., without individual video monitor and carry case). These cameras are reasonably priced (US$129.99), provide an 858 wide-angle field of view and quality video output (resolution ¼ 560 3 480 pixels), have six infrared light-emitting diodes (LEDs) for low-light capabilities, are designed to withstand depths of 91.4 m, and come with a 12-month manufacturer warranty against leakage and defects (Table 1). The LEDs were important for maximizing visibility during late afternoon and as turbidity increased during water releases. We identified the types of substrata that were most commonly associated with nests (i.e., sand, gravel, and cobble matrix), and we designed substrate stakes (Figure 2) to secure cameras in the substrata and prevent dislodgment due to rapidly increasing discharge. Securing the cameras was a priority since they were often left overnight. A local metal shop fabricated substrate stakes from 908-angle aluminum at material cost (Table 2). Each n-shaped stake consisted of two 28-cm legs and a 15-cm-wide cradle for the camera.
1365
1366
MARTIN AND IRWIN
TABLE 1.—Technical specifications of the digital video recorder (DVR; CMC Tech, Inc., motion JPEG triplex network DVR) used to capture and store simultaneous underwater video and the SeaView SuperMini black-and-white underwater video camera (UVC). Specifications Model number Manufacturer’s suggested retail price Warranty Channels Video input Video output Audio input/output Hard drive Display division Dimensions Capture rate Camera image Weight Cable length Light source Illumination Field of view Range Lines of resolution Signal type Maximum depth
DVR
UVC
DVR16TN-USB-CDRW US$599.00
SM-50-C US$129.99
12 months 16 16 (female BNCa) 1 female BNC, VGAb, or S-videoc RCA in/RCA out 160 gigabytes 1, 4, 9, 16 43 3 36 3 7 cm 1/30 to 120 frames/s
12 months Male RCAd
6.4 3 10.8 cm Black and white 1.8 kg 15.2 m (upgradable to 91.4 m) 6 infrared LEDse (950 nm) 0 lx @ f/2.6 858 wide angle 15.2 cm–‘ 420 (560 3 480 pixels) NTSCf 91.4 m
a
Bayonet Neill Concelman connection. Video graphics array connection. Separate video connection. d Radio Corporation of America connector. e Light-emitting diodes. f National Television System Committee standard. b c
The terminal ends of each leg were mitered at an angle to form sharp points for easy penetration of the substrate. The top of each stake leg was mitered to attach the 15-cm cradle with a weld bead; the cradle
formed a v-shape when the stake was in an upright position (Figure 2). System deployment.—All equipment and operators were secured in a johnboat tied to the riverbank at both bow and stern, with the bow facing upstream. Lines were fastened to secure points approximately 2.5 m above the waterline to ensure safety during rapidly rising water discharges released from the dam. Redbreast sunfish nesting colonies were located by snorkeling along the riverbanks, and substrate stakes were secured adjacent to nests and angled toward the nest center at an approximately 458 angle. Each UVC TABLE 2.—Additional equipment required for the digital underwater video camera system, with amount or number needed shown in parentheses.
FIGURE 1.—Schematic diagram of the individual components of the digital underwater video camera system, illustrating both the video and camera systems (DVR ¼ digital video recorder; Cam ¼ camera).
Equipment
Approximate cost (US$)
908-angle aluminum (710 cm) Hose clamps (10) Video monitor (1) BNC–RCAa adapters (10) 400-W inverter (1) Deep-cycle batteries (2) 12-V socket splitter (4) Stand-alone DVD recorder (1) Tent stakes (40)
30 25 90 20 30 200 60 100 28
a
BNC ¼ Bayonet Neill Concelman; RCA ¼ Radio Corporation of America.
1367
MANAGEMENT BRIEF
Cameras were recovered the next morning to avoid collection during hazardous conditions, whereas the remainder of the system was removed and the batteries were recharged before any subsequent recordings. Data were automatically stored on the DVR’s 160-gigabyte hard drive at 60 frames/s and ensured data collection even in the event of camera loss. A stand-alone digital video disk recorder was used to back up the recorded video after data were collected. Results and Discussion
FIGURE 2.—Schematic diagram of a custom-fabricated stake used to attach the underwater video cameras to the substrate. The stakes (28 cm tall 3 15 cm wide) were constructed from 908-angle aluminum. Panel (A) represents a side view, with the camera depicted in the cradle. The gray areas at the top left and right represent weld beads. Panel (B) illustrates how the 908 aluminum on top forms the camera cradle.
was attached to a substrate stake with a hose clamp; cables were then directed to the boat and anchored to the substrate with plastic tent stakes to avoid interference with surrounding nests or ensnarement during high discharge. Variable cable length allowed nests to be observed at varying distances to the DVR and allowed some leniency in nest selection. Once cameras were secured, attached to the deep-cycle battery, and connected to the DVR, each video feed was viewed on the video monitor to ensure a proper field of view. After all cameras were properly positioned, a 15-min period elapsed to permit fish acclimation to the presence of equipment before recording took place. As discharge increased, bow and stern lines were retracted and camera cables were lengthened to reduce stress and maintain a perpendicular angle to the water surface. Recording times averaged 2 h but varied due to time of day and water clarity. Video data were usually collected in late afternoon and early evening to capture behavior before and leading up to peak discharge until turbidity or limited light conditions halted recording.
The described UVC system was an effective tool for monitoring and recording behavior of nesting redbreast sunfish in a regulated river (Martin 2008), and over 140 h (;14 h 3 10 cameras) of video data were collected during 2006 and 2007. Reproductive behaviors did not appear to be affected by the presence of cameras or substrate stakes as defensive, courtship, and spawning behaviors were observed multiple times during recordings. Behavior biases were probably further reduced by the choice of DC power to minimize noise. The fabrication of substrate stakes and their ability to hold cameras in position during discharge events were critical aspects required for our specific application. Although no debris or dislodgement tests were performed on the substrate stakes prior to data collection, they proved to be capable of withstanding high-flow events (~300 m3/s) without displacement, damage, or loss of cameras. Advantages of our UVC system primarily include the substrate stake design, which allowed recording during extreme flow conditions, and the ability to collect reproductive behaviors of multiple fish simultaneously. Also, the cameras were reasonably priced in comparison with similar underwater video cameras described by other researchers in the aquatic literature, and this system can easily accommodate other projects because of the flexibility of the DVR. Digital video recorders have been used for recording fish (i.e., salmonid) passage at dams and small tributaries in the western USA (Johnson et al. 2007), and our system is capable of this type of monitoring. The DVR was underutilized and could be used to capture instantaneous videos by detecting movement through onboard sensitivity controls. This could be beneficial for use in identifying fish species, size, and weight (Costa et al. 2009) and for examining habitat use (Pratt et al. 2005) and dam passage. A combination of this system with telemetry systems could be used to effectively monitor fish movement (Li et al. 2007). Conversely, the UVC system used in the present study may not be practical in all situations for underwater research but does allow for flexibility. The DVR was not able to back up video data onto
1368
MARTIN AND IRWIN
DVDs without the purchase of a stand-alone DVD recorder, which slowed postprocessing of video data because backup was conducted in real time. A potential drawback of the cameras was the hard-wired cables; if cables are damaged, the cameras would probably need to be sent to the manufacturer for repair. This particular feature would not have been useful in our research because river conditions would have precluded detachment at the camera–cable interface. A cathode ray tube video monitor was used, and bright light often hindered our ability to confirm the position of the cameras. The use of a matte, flat-screen, liquid crystal display video monitor would resolve this issue and further provide a compact and similarly priced replacement. Aquatic monitoring is often limited by the inability to visually observe fauna (e.g., behavior, enumeration, or size estimation). Such data are often critical for decision making relative to conservation and management of aquatic resources. Direct observation of redbreast sunfish reproductive behavior during discharge disturbances allowed for quantification of nesting behaviors in relation to increased discharge. Specifically, monitoring of redbreast sunfish reproductive behavior has increased our knowledge of functional responses (i.e., nest survival) to discharge. Consequently, findings are directly transferable to support the structured decision-making tool (Bayesian belief network) described by Kennedy et al. (2006) for adaptive management of the Tallapoosa River below Harris Dam. These results led to recommendations for timing of spawning windows and allowed the decision support model to be updated with redbreast sunfish spawning success. Information in this manuscript provides details of a flexible system that is capable of recording multiple video feeds during deployment in a highly regulated river and associated harsh conditions. Additionally, the novel substrate stake design described here made recording possible in these conditions. Through creative modification of the described system for specific research applications, quality visual images of aquatic fauna can be recorded and analyzed to enhance conservation and management efforts. Acknowledgments The authors are members of the Alabama Cooperative Fish and Wildlife Research Unit, which consists of the U.S. Geological Survey; the Alabama Agricultural Experiment Station, Auburn University; the Alabama Department of Conservation and Natural Resources, Division of Wildlife and Freshwater Fisheries; the Wildlife Management Institute; and the U.S. Fish and Wildlife Service. This research was funded by the Alabama Department of Conservation and Natural Resources, Division of Wildlife and
Freshwater Fisheries, the Alabama Power Company, and the U.S. Geological Survey. We thank Jeff Holder, Chase Katechis, Molly Martin, and Josh Moore for their assistance with this research. P. Bettoli, J. Jolley, and two anonymous reviewers provided constructive comments on the manuscript. The use of trade, product, industry, or firm names or products, software, or models, whether commercially available or not, is for informative purposes only and does not constitute an endorsement by the U.S. Government or the U.S. Geological Survey. References Bettoli, P. W., and P. W. Clark. 1992. Behavior of sunfish exposed to herbicides: a field study. Environmental Toxicology and Chemistry 11:1461–1467. Carbines, G., and R. G. Cole. 2008. Using a remote drift underwater video (DUV) to examine dredge impacts on demersal fishes and benthic habitat complexity in Foveaux Strait, southern New Zealand. Fisheries Research 96:230–237. Chidami, S., G. Guenard, and M. Amyot. 2007. Underwater infrared video system for behavioral studies in lakes. Limnology and Oceanography: Methods 5:371–378. Cooke, S. J., and C. M. Bunt. 2004. Construction of a junction box for use with an inexpensive, commercially available underwater video camera suitable for aquatic research. North American Journal of Fisheries Management 24:253–257. Cooke, S. J., J. F. Schreer, D. P. Philipp, and P. J. Weatherhead. 2003. Nesting activity, parental care behavior, and reproductive success of smallmouth bass, Micropterus dolomieu, in an unstable thermal environment. Journal of Thermal Biology 28:445–456. Costa, C., M. Scardi, V. Vitalini, and S. Cataudella. 2009. A dual camera system for counting and sizing northern bluefin tuna (Thunnus thynnus; Linnaeus, 1758) stock, during transfer to aquaculture cages, with a semi automatic artificial neural network tool. Aquaculture 291:161–167. Groves, P. A., and A. P. Garcia. 1998. Two carriers used to suspend an underwater video camera from a boat. North American Journal of Fisheries Management 18:1004– 1007. Hinch, S. G., and N. C. Collins. 1991. Importance of diurnal and nocturnal nest defense in the energy budget of male smallmouth bass; insights from direct video observations. Transactions of the American Fisheries Society 120:657– 663. Johnson, P. N., M. D. Rayton, B. L. Nass, and J. E. Arterburn. 2007. Enumeration of salmonids in the Okanogan Basin using underwater video: performance period—October 2005–31 December 2006. Bonneville Power Administration, Technical Report, Project 2003-022-00, Portland, Oregon. Kennedy, K. M., E. R. Irwin, M. C. Freeman, and J. Peterson. 2006. Development of a decision support tool and procedures for evaluating dam operation in the southeastern United States. USGS (U.S. Geological Survey), Science Support Partnership Program, Final Report to
MANAGEMENT BRIEF
USGS, Reston, Virginia, and U.S. Fish and Wildlife Service, Atlanta. Li, X., M. K. Litvak, and J. E. H. Clarke. 2007. Overwintering habitat use of shortnose sturgeon (Acipenser brevirostrum): defining critical habitat using a novel underwater video survey and modeling approach. Canadian Journal of Fisheries and Aquatic Sciences 64:1248–1257. Martin, B. M. 2008. Nest survival, nesting behavior, and bioenergetics of redbreast sunfish on Tallapoosa River, Alabama. Master’s thesis. Auburn University, Alabama. Myrick, C. A. 2009. A low-cost system for capturing and
1369
analyzing motion of aquatic organisms. Journal of the North American Benthological Society 28:101–109. Pratt, T. C., K. E. Smokorowski, and J. R. Muirhead. 2005. Development and experimental assessment of an underwater video technique for assessing fish-habitat relationships. Archive of Hydrobiology 164:547–571. Steinhart, G. B., M. E. Sandrene, S. Weaver, R. A. Stein, and E. A. Marschall. 2004. Increased parental care cost for nest-guarding fish in a lake with hyperabundant nest predators. Behavioral Ecology 16:427–343.
