Accuracy and Precision of Visual Estimates and Photogrammetric Measurements of the Length of a Small‐bodied Fish

Bower, Michael R.; Gaines, D. Bailey; Wilson, Kevin P.; Wullschleger, John G.; Dzul, Maria C.; Quist, Michael C.; Dinsmore, Stephen J.

doi:10.1080/02755947.2011.562737

Cited by 11 publications

(6 citation statements)

References 22 publications

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“…As alternatives to physical measurements, fish lengths have been measured with nonintrusive methods, such as visual assessment (Harvey et al 2001;Edgar et al 2004); sonar acoustic cameras (Mueller et al 2006); and photogrammetry techniques (Welsh and Aldinger 2014), including paired-laser photogrammetry (Rochet et al 2006;Deakos 2010), stereo video equipment (Bower et al 2011;Shortis et al 2013;Langlois et al 2015), and underwater video with paired lasers (Yoshihara 1997). Nonintrusive methods of fish measurement are useful when it is difficult or undesirable to capture individuals with conventional sampling gear, such as in deep sea environments (Dunlop et al 2015); at fish passage facilities (Welsh and Aldinger 2014); when fishes are too large to capture, such as Whale Sharks Rhincodon typus (Rohner et al 2011); when fish are sensitive to stress of capture and handling (Molinero and Gonzalez 1995;Snyder 2003); and for protected areas or protected species (Harvey et al 2001;Jack and Wing 2010).…”

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confidence: 99%

A Paired‐Laser Photogrammetric Method for In Situ Length Measurement of Benthic Fishes

Rizzo

Welsh

Thompson

2016

N American J Fish Manag

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Photogrammetry, a technique to obtain measurements from photographs, may be a valid method for measuring lengths of rare, threatened, or endangered species. Photogrammetric methods of measurement are nonintrusive and reduce the possibility of physical damage or physiological stress associated with the capture and handling of individuals. We evaluated precision and accuracy of photogrammetric length measurements relative to board measurements of Greenside Darters Etheostoma blennioides and Variegate Darters E. variatum in an aquarium and applied photogrammetry in a field study of the Diamond Darter Crystallaria cincotta, a federally listed endangered species. Digital photographs were taken of each individual using a waterproof camera equipped with two parallel lasers. Photogrammetric length measurements were digitized with ImageJ software. Agreement between board and photogrammetric measurements were high for Greenside and Variegate darters. The magnitude of differences was small between direct and photogrammetric measurements, ranging from 0.6% to 3.1%, depending on the species measured and the type of measurement taken. These results support photogrammetry as a useful method for obtaining length measurements of benthic stream fishes. Photogrammetric methods allowed for length measurements and an assessment of length frequency of 199 Diamond Darters, informative data for management that could not be collected with conventional measuring-board methods.

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confidence: 99%

A Paired‐Laser Photogrammetric Method for In Situ Length Measurement of Benthic Fishes

Rizzo

Welsh

Thompson

2016

N American J Fish Manag

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“…For example, length measurements of Saratoga Springs pupfish, C. nevadensis nevadensis, generated from a SV system had negligible bias and greater precision compared to visual estimates from SCUBA divers (Bower et al 2011). We used SV technology to obtain monthly length-frequency distributions of the Devils Hole pupfish population.…”

Section: Estimation Of Length-frequency Distributionsmentioning

confidence: 99%

“…Stereo-video technology (SV) presents a powerful tool for non-obtrusively collecting accurate and precise length measurements (Harvey et al 2002(Harvey et al , 2004. For example, length measurements of Saratoga Springs pupfish, C. nevadensis nevadensis, generated from a SV system had negligible bias and greater precision compared to visual estimates from SCUBA divers (Bower et al 2011). We used SV technology to obtain monthly length-frequency distributions of the Devils Hole pupfish population.…”

Section: Estimation Of Length-frequency Distributionsmentioning

confidence: 99%

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A simulation model of the Devils Hole pupfish population using monthly length‐frequency distributions

et al. 2013

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The Devils Hole pupfish, Cyprinodon diabolis, is a federally-endangered fish that is endemic to Devils Hole, a discontiguous part of Death Valley National Park in Nye County, Nevada. Due to its status, Devils Hole pupfish monitoring must be non-obtrusive and thereby exclude techniques that require handling fish. Due to a recent decline in pupfish abundance, Devils Hole pupfish managers have expressed a need for a model that describes population dynamics. This population model would be used to identify vulnerable life history stage(s) and inform management actions. We constructed a set of individualbased simulation models designed to explore effects of population processes and evaluate assumptions. We developed a baseline model, whose output best resembled both observed length-frequency data and predicted intraannual abundance patterns. We then ran simulations with 5 % increases in egg-larval, juvenile, and adult survival rates to better understand Devils Hole pupfish life history, thereby helping identify vulnerable life history stages that should become the target of management actions. Simulation models with temporally constant adult, juvenile, and egg-larval survival rates were able to reproduce observed length-frequency distributions and predicted intraannual population patterns. In particular, models with monthly adult and juvenile survival rates of 80 % and an egg-larval survival rate of 4.7 % replicated patterns in observed data. Population growth was most affected by 5 % increases in egg-larval survival, whereas adult and juvenile survival rates had similar but lesser effects on population growth. Outputs from the model were used to assess factors suspected of influencing Devils Hole pupfish population decline. Abstract The Devils Hole pupfish, Cyprinodon diabolis, is a federally-endangered fish that is endemic to Devils Hole, a discontiguous part of Death Valley National Park in Nye County, Nevada. Due to its status, Devils Hole pupfish monitoring must be non-obtrusive and thereby exclude techniques that require handling fish. Due to a recent decline in pupfish abundance, Devils Hole pupfish managers have expressed a need for a model that describes population dynamics. This population model would be used to identify vulnerable life history stage(s) and inform management actions. We constructed a set of individualbased simulation models designed to explore effects of population processes and evaluate assumptions. We developed a baseline model, whose output best resembled both observed length-frequency data and predicted intraannual abundance patterns. We then ran simulations with 5 % increases in egg-larval, juvenile, and adult survival rates to better understand Devils Hole pupfish life history, thereby helping identify vulnerable life history stages that should become the target of management actions. Simulation models with temporally constant adult, juvenile, and egg-larval survival rates were able to reproduce observed length-frequency distributions and predicted intra-annual population patte...

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“…A range of other marine biology applications also routinely use stereoimaging techniques (photo as well as video), including: fish monitoring (Ruff et al, 1995;Van Rooij et al, 1995;Li et al, 1996;Tillett et al, 2000;Harvey et al, 2003;Costa et al, 2006;Costa et al, 2009;Rooper et al, 2010;Bower et al, 2011;Torisawa et al, 2011); determination of the 3D structure of fish schools (Cullen et al, 1965;Pitcher, 1975;Dill et al, 1981;Sawada et al, 2009); determination of the influence of substrate complexity on the interaction between fish and the artificial substrate (Fischer et al, 2007); and surveys of the benthos and the sea floor (Emerey et al, 1965;Evans and Norris, 1997;Chong and Stratford, 2002;Jasiobedzki et al, 2008;Shortis et al, 2008;Svane et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

A practical guide to the use of consumer-level digital still cameras for precise stereogrammetric <I>in situ</I> assessments in aquatic environments

Wehkamp¹,

Fischer²

2014

uw tech: int j soc uw tech

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Scientists planning to use underwater stereoscopic image technologies are often faced with numerous problems during the methodological implementations: commercial equipment is too expensive; the setup or calibration is too complex; or the imaging processing (i.e. measuring objects in the stereo-images) is too complicated to be performed without a time-consuming phase of training and evaluation. The present paper addresses some of these problems and describes a workflow for stereoscopic measurements for marine biologists. It also provides instructions on how to assemble an underwater stereo-photographic system with two digital consumer cameras and gives step-by-step guidelines for setting up the hardware. The second part details a software procedure to correct stereo-image pairs for lens distortions, which is especially important when using cameras with non-calibrated optical units. The final part presents a guide to the process of measuring the lengths (or distances) of objects in stereoscopic image pairs. To reveal the applicability and the restrictions of the described systems and to test the effects of different types of camera (a compact camera and an SLR type), experiments were performed to determine the precision and accuracy of two generic stereo-imaging units: a diver-operated system based on two Olympus Mju 1030SW compact cameras and a cable-connected observatory system based on two Canon 1100D SLR cameras. In the simplest setup without any correction for lens distortion, the low-budget Olympus Mju 1030SW system achieved mean accuracy errors (percentage deviation of a measurement from the object's real size) between 10.2 and -7.6% (overall mean value: -0.6%), depending on the size, orientation and distance of the measured object from the camera. With the single lens reflex (SLR) system, very similar values between 10.1% and -3.4% (overall mean value: -1.2%) were observed. Correction of the lens distortion significantly improved the mean accuracy errors of either system. Even more, system precision (spread of the accuracy) improved significantly in both systems. Neither the use of a wide-angle converter nor multiple reassembly of the system had a significant negative effect on the results. The study shows that underwater stereophotography, independent of the system, has a high potential for robust and non-destructive in situ sampling and can be used without prior specialist training.

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Accuracy and Precision of Visual Estimates and Photogrammetric Measurements of the Length of a Small‐bodied Fish

Cited by 11 publications

References 22 publications

A Paired‐Laser Photogrammetric Method for In Situ Length Measurement of Benthic Fishes

A Paired‐Laser Photogrammetric Method for In Situ Length Measurement of Benthic Fishes

A simulation model of the Devils Hole pupfish population using monthly length‐frequency distributions

A practical guide to the use of consumer-level digital still cameras for precise stereogrammetric <I>in situ</I> assessments in aquatic environments

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