Visual Census of Reef Fish Assemblages: A Comparison of Slate, Audio, and Video Recording Devices

Bortone, Stephen A.; Martin, Tony; Bundrick, Charles M.

doi:10.18785/negs.1201.02

Cited by 27 publications

(28 citation statements)

References 8 publications

(8 reference statements)

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“…In this direction, Okamoto (1989) has compared ROV visual censuses with other techniques in an aquarium tank while Spanier et al (1994) stressed the need to conduct comparative studies of the relative utility of scuba versus ROV technologies for observing the behavior of marine animals. Moreover, several studies have also tested census techniques by means of underwater video recordings from a fixed point (Francour et al 1999), video-operator (Bortone et al 1991;Harvey et al 2002;Tessier et al 2005) or submersibles (Love et al 2000). ROV, equipped with high definition video cameras, are increasingly used as a tool for underwater investigation, being capable to reach depths inaccessible to scuba divers and to record data even in adverse operative conditions.…”

Section: Introductionmentioning

confidence: 99%

Assessing the suitability of a remotely operated vehicle (ROV) to study the fish community associated with offshore gas platforms in the Ionian Sea: a comparative analysis with underwater visual censuses (UVCs)

et al. 2012

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The effectiveness of a remotely operated vehicle (ROV) to describe the fish communities of three gas platforms located offshore Crotone (Italy, Ionian Sea) was investigated by comparing its observations with underwater visual censuses (UVCs). The study was carried out at two depth layers (0-6 and 12-18 m). Moreover, the ROV was used to survey three deeper depth layers up to 76 m. Overall, the ROV surveys failed to give a truthful representation of the fish communities underestimating the number of species and their abundances as compared to UVCs. The main discrepancies in data regarded cryptobenthic and nekto-benthic species, whereas the ROV proved to be a suitable method to census low-mobile and abundant planktivorous species. The differences between the fish assemblage described by the ROV, with respect to the one depicted by UVC, should be considered in the light of the technical limits of the recording camera, whose resolution and field of vision is clearly lower than the diver's eye. In addition, video images did not allow for the acquisition of a correct estimate of the distance between the individuals and the platform structures. This led, almost certainly, to an under-or over-estimation of fish abundance as regards to the censused volume. In spite of this, as a result of its capacity to reach depths inaccessible to scuba divers and then to add complementary information, the ROV could be used jointly with UVCs, in studies having as their objective the description of the fish communities associated with offshore platforms.

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Section: Introductionmentioning

confidence: 99%

Assessing the suitability of a remotely operated vehicle (ROV) to study the fish community associated with offshore gas platforms in the Ionian Sea: a comparative analysis with underwater visual censuses (UVCs)

et al. 2012

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“…Their separation is especially difficult where the target organisms are highly mobile within the time taken to complete a count, such as with underwater surveys of fishes. Several authors have examined sources of methodological error in underwater visual surveys of fishes, including the counting method (Sale & Douglas 1981, DeMartini & Roberts 1982, Kimmel 1985, Sanderson & Solonsky 1986, Thresher & Gunn 1986, Greene & Alevizon 1989, Bortone et al 1991, Samoilys 1992, Mapstone & Ayling 1993, the numbers of taxa counted simultaneously (Russell et al 1978, Greene & Alevizon 1989, Lincoln-Smith 1989, the speed with which counts are done (Mapstone 1988, Lincoln-Smith 1989, St. John et al 1990, and the shape and dimensions of sampling units (Sale & Sharp 1983, Fowler 1987, McCormick & Choat 1987, Mapstone 1988, Buckley & Hueckel 1989, Mapstone & Ayling 1993.…”

Section: Introductionmentioning

confidence: 99%

Observer effects and training in underwater visual surveys of reef fishes

Aa¹,

Bd²

1997

Mar. Ecol. Prog. Ser.

145

107

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Visual survey techniques are used widely to estimate abundances of target organisms in terrestrial and aquatic environments. There are a number of methodological 'errors' in almost all applications of visual surveys. Given the dependence of all visual survey data on the skill and technique of the observer, one potentially important source of imprecision andlor bias is vanation among and within observers. In studies involving large amounts of fieldwork over great geographic range and many years, it is inevitable that observers will change from place to place and through time at any single site as they are replaced or gwn experience. We present the results of 3 observer tralningkalibration exercises that lnd~cate that observational studies in which multiple observers must be employed may be subject to considerable observer-related biases and imprecision. We found that careful training and calibration of observers ameliorated such effects for most taxa, but non-trivial levels of bias for some taxa and imprecision m estimates for several taxa remained even after thorough training. It is essential that the influence of observer bias and impreclslon be well documented in multi-observer monitoring studies, so that (spurious) patterns related to differences among observers can be distinguished from real spatial or temporal patterns in the environment.

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“…As the two methods have the ability to collect data over the same spatial area, information should be relatively comparable, allowing for a combination of methods within a single assessment program. The comparability of the data produced by UVC and single camera DOV has previously been demonstrated in studies conducted in large aquaria (Greene and Alevizon 1989;Bortone et al 1991) and coral reefs on oceanic islands (Tessier et al 2005;Pelletier et al 2011). However, how UVC and stereo-DOV compare, and how this differs across a range of biogeographic regions (e.g., temperate rocky reefs and sub-tropical fringing reefs) where there are large variations in habitat complexity, water visibility, fish diversity, and abundance, is currently relatively unknown.…”

mentioning

confidence: 78%

“…Underwater video camera techniques have increasingly been used for assessing shallow water fish assemblages in more recent times (e.g., Bortone et al 1991;Parker et al 1994;Moser et al 1998), and the continued development of camera technology has enabled rapid advances in these techniques (e.g., image resolution, storage capacity, software capabilities; Shortis et al 2009). Using two cameras set in a stereo configuration enables precise estimates of fish lengths, which allows robust evaluation of size distributions and biomass where length/weight relationships are known .…”

mentioning

confidence: 99%

Untitled

2013

Limnology & Ocean Methods

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A central issue in the development of marine research and monitoring programs is the identification of robust methodologies aimed at detecting spatial and temporal changes in abundance, diversity, and biomass of faunal assemblages (e.g., Maxwell and Jennings 2005;Cheal et al. 2008;Murphy and Jenkins 2010). Decisions on how to assess these metrics are initially based on the type of information required, what specific indices must be measured, the level of precision required to detect change, the repeatability of the method, and the environmental conditions under which assessments will take place (Connell et al. 1998;Willis et al. 2000;Smale et al. 2011). Importantly, the human capital and financial resources available to collect data must also be considered, as costs associated with different data collection techniques can vary substantially . However, for long-term monitoring projects technological advancements, scientific innovations, sporadic funding, and changes in the availability of staff expertise often mean that the most suitable assessment methods change through time (Murphy and Jenkins 2010). This may result in time-series datasets that are collected using several techniques. To ensure that trends in data are not attribut- AbstractRobust assessments of abundance and diversity are essential components of research programs aimed at detecting changes in marine fish assemblages through space and time. This study examined the comparability of Underwater Visual Census (UVC), and Diver Operated stereo-Video (Stereo-DOV) datasets collected across a wide latitudinal range (15°) on coral reefs and temperate rocky shores. There were some differences between methods with regards to both species richness and abundance, with UVC consistently recording higher measures of species richness. Differences were most pronounced at tropical locations where these measures were high. Differences in the characteristics of fish assemblages were primarily driven by UVC differentiating between scarid and pomacentrid species and detecting more cryptic species. When examined at higher taxonomic or functional levels however, there was greater comparability between the assemblages recorded by each method, particularly in temperate locations. The UVC method also recorded higher abundances of species targeted by fishers in tropical/sub-tropical locations, and subsequently obtained a much higher proportion of length measurements for these species. Data collected using stereo-DOV took 2-3 times longer to obtain than with UVC due to extensive post-processing time required by the stereo-DOV method. This study shows that data collected by the two methods are most comparable in temperate locations, or when examined at higher taxonomic/functional levels. Comparisons should however be more cautious in higher diversity locations, or when assessing at finer taxonomic resolution. When assessing the suitability of either method, availability of time, funding, and relevant expertise should be primary considerations.

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Visual Census of Reef Fish Assemblages: A Comparison of Slate, Audio, and Video Recording Devices

Cited by 27 publications

References 8 publications

Assessing the suitability of a remotely operated vehicle (ROV) to study the fish community associated with offshore gas platforms in the Ionian Sea: a comparative analysis with underwater visual censuses (UVCs)

Assessing the suitability of a remotely operated vehicle (ROV) to study the fish community associated with offshore gas platforms in the Ionian Sea: a comparative analysis with underwater visual censuses (UVCs)

Observer effects and training in underwater visual surveys of reef fishes

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