Precision as a metric for acoustic survey design using occupancy or spatial capture-recapture

Line-transect distance sampling is a widely used method for estimating animal density from aerial surveys. Analysis of line-transect distance data usually relies on a requirement that the statistical distribution of distances of animal groups from the transect line is uniform. We show that this requirement is satisfied by the survey design if all other assumptions of distance sampling hold, but it can be violated by consistent survey problems such as responsive movement of the animals towards or away from the observer. We hypothesise that problems with the uniform requirement are unlikely to be encountered for immobile taxa, but might become substantial for species of high mobility. We test evidence for non-uniformity using double-observer distance data from two aerial surveys of five species with a spectrum of mobility capabilities and tendencies. No clear evidence against uniformity was found for crabeater seals or emperor penguins on the pack-ice in East Antarctica, while minor non-uniformity consistent with responsive movement up to 30 m was found for Adelie penguins. Strong evidence of either non-uniformity or a failure of the capture–recapture validating method was found for eastern grey kangaroos and red kangaroos in Queensland.

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Target strength measurement of Caroun croaker (Johnius sp.) and acoustic fish density estimation in Musi Estuary, South Sumatra

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/944/1/012008 ◽

2021 ◽

Vol 944 (1) ◽

pp. 012008

Author(s):

F Supriyadi ◽

I Jaya ◽

S Pujiyati ◽

T Hestirianoto ◽

Z Fahmi

Keyword(s):

Survey Design ◽

Economic Value ◽

Acoustic Pulse ◽

Target Strength ◽

Estuarine Fish ◽

Fish Length ◽

Acoustic Survey ◽

Strength Measurement ◽

Fish Stocks ◽

Length Relationship

Abstract Caroun Croaker ( Johnius sp.) is one of the dominant estuarine fish that has a reasonably high economic value. The target strength (TS) value measurement is essential in calculating the density of fish stocks using the hydroacoustic method. Target strength measurement of Caroun Croaker (Johnius sp.) and an acoustic survey in Musi Estuary Waters of South Sumatra Province was conducted in December 2019. The result of TS measurement will be used to estimate the acoustic density along the survey area. The TS measurement used the standard tethered method, tying placing the fish in a fixed cage, transmitting the acoustic pulse, and analyzing its return using the scientific acoustic instrument Biosonic DT-X 200 KHz. The fisheries acoustic survey was carried out in the area around the Musi estuary with a predetermined survey design. The results of the measurements have obtained the TS-length relationship, as TS= 20 LOG L-78.79 with determinant value of R2= 0.67 for fish length ranges from 18.1-23.3 cm, and an acoustic survey showed that the estimated stock density value was 286 kg/ha for the total surveyed area of 1.612 ha.

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Precision as a metric for acoustic survey design using occupancy or spatial capture-recapture

10.1101/2020.09.30.321521 ◽

2020 ◽

Author(s):

Julius Juodakis ◽

Isabel Castro ◽

Stephen Marsland

Keyword(s):

Survey Design ◽

Rapid Development ◽

Temporal Trends ◽

Cost Effective ◽

Sampling Effort ◽

Occupancy Modelling ◽

Call Recognition ◽

Animal Populations ◽

Wide Range ◽

Capture Recapture

AbstractPassive acoustic surveys provide a convenient and cost-effective way to monitor animal populations. Methods for conducting and analysing such surveys, especially for performing automated call recognition from sound recordings, are undergoing rapid development. However, no standard metric exists to evaluate the proposed changes. Furthermore, most metrics that are currently used are specific to a single stage of the survey workflow, and therefore may not reflect the overall effects of a design choice.Here, we attempt to define and evaluate the effectiveness of surveys conducted in two common frameworks of population inference – occupancy modelling and spatially explicit capture-recapture (SCR). Specifically, we investigate precision (standard error of the final estimate) as a possible metric of survey performance, but we show that it does not lead to generally optimal designs in occupancy modelling. In contrast, precision of the SCR density estimate can be optimised with fewer experiment-specific parameters. We illustrate these issues using simulations.We further demonstrate how SCR precision can be used to evaluate design choices on a field survey of little spotted kiwi (Apteryx owenii). We show that precision correctly measures tradeoffs involving sampling effort. As a case study, we compare automated call recognition software with human annotations. The proposed metric captured the tradeoff between missed calls (8% loss of precision when using the software) and faster data through-put (60% gain), while common metrics based on per-second agreement failed to identify optimal improvements and could be inflated by deleting data.Due to the flexibility of SCR framework, the approach presented here can be applied to a wide range of different survey designs. As the precision is directly related to the power of detecting temporal trends or other effects in the subsequent inference, this metric evaluates design choices at the application level, and can capture tradeoffs that are missed by stage-specific metrics, thus enabling reliable comparison between different experimental designs and analysis methods.

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Patchy Distribution Fields: Acoustic Survey Design and Reconstruction Adequacy

Environmental Monitoring ◽

10.1201/9780203495476-25 ◽

2004 ◽

pp. 487-520

Keyword(s):

Survey Design ◽

Acoustic Survey ◽

Patchy Distribution

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An adaptive, integrated “acoustic-trawl” survey design for Atlantic cod (Gadus morhua) with estimation of the acoustic and trawl dead zones

ICES Journal of Marine Science ◽

10.1016/j.icesjms.2004.06.023 ◽

2005 ◽

Vol 62 (1) ◽

pp. 93-106 ◽

Cited By ~ 38

Author(s):

Ian H. McQuinn ◽

Yvan Simard ◽

Thomas W.F. Stroud ◽

Jean-Louis Beaulieu ◽

Stephen J. Walsh

Keyword(s):

Gadus Morhua ◽

Sampling Design ◽

Atlantic Cod ◽

Survey Design ◽

Dead Zone ◽

Total Biomass ◽

Trawl Survey ◽

Acoustic Survey ◽

Night Time ◽

Diel Vertical Migrations

Abstract The objectives of this study were to design an operationally efficient groundfish survey integrating both acoustic and trawl methodologies, to measure the changing vertical availability of cod to each method over 24 h and to compare cod-biomass estimates from the two methods within two experimental sub-regions. The two-phased sampling design involved (i) conducting an initial systematic acoustic survey to locate an area of high cod concentrations, (ii) using the acoustic-backscatter information to stratify the sub-regions into density strata for the allocation of trawl hauls, and (iii) conducting a second systematic acoustic survey at the same time as a random-stratified trawl survey. This protocol permitted the optimization of trawl sampling according to population density and the realization of simultaneous trawl and acoustic estimates for direct comparison. These cod showed extensive diel vertical migrations, which affected their availability to the trawl gear at night and the acoustic beam by day. An acoustic dead-zone correction was applied to the acoustic estimates, averaging 4–15% of the biomass for the night-time transects and 11–36% for the daytime transects. The detailed temporal acoustic monitoring of the vertical migrations permitted the quantification of the change in cod availability to the trawl gear. From 6% to 47% of cod were above the effective trawl height at night, while 0–10% of cod were in the “trawl dead zone” by day. Estimated cod densities were very similar between the two methods on a haul-by-haul basis after correcting each method for their respective inherent sampling biases. The total biomass estimates were also comparable between the two methods for one sub-region, although significantly higher from the trawl data for the other. The discrepancies were most likely a result of differences in the sampling density of the two methods.

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The use of an adaptive acoustic-survey design to estimate the abundance of highly skewed fish populations

ICES Journal of Marine Science ◽

10.1093/icesjms/fsp088 ◽

2009 ◽

Vol 66 (6) ◽

pp. 1349-1354 ◽

Cited By ~ 6

Author(s):

Alf Harbitz ◽

Egil Ona ◽

Michael Pennington

Keyword(s):

Root Mean Square Error ◽

Mean Square Error ◽

Root Mean Square ◽

Survey Design ◽

Clupea Harengus ◽

Fish Populations ◽

North Coast ◽

Acoustic Survey ◽

Mean Square ◽

Abundance Estimates

Abstract Harbitz, A., Ona, E., and Pennington, M. 2009. The use of an adaptive acoustic-survey design to estimate the abundance of highly skewed fish populations. – ICES Journal of Marine Science, 66: 1349–1354. The uncertainty (relative root-mean-square error) of abundance estimates based on a simple and easily implemented adaptive design for an acoustic survey is examined. The study is limited to surveys with parallel transects and independent observations with extremely skewed distributions. The adaptive approach defines a stratum for each conventional observation and how to take additional observations in that stratum when the acoustic density exceeds a predetermined threshold. The cost (sailing distance) of each added observation is about three times that of a conventional observation. This method was demonstrated using high-resolution transect data from a herring (Clupea harengus) acoustic survey conducted in 2006 off the north coast of Norway. The primary sampling unit for this winter survey was 5 nautical miles, and the usual distance between transects was 20 nautical miles. The results indicate that an adaptive survey design would substantially reduce the root-mean-square error of the abundance estimates compared with that of the conventional survey design.

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Measuring Abundance

10.53061/ovcj4115 ◽

2020 ◽

Author(s):

Graham Upton

Keyword(s):

Prince Edward Island ◽

Survey Design ◽

Plant Cover ◽

Distance Sampling ◽

Species Abundance ◽

Ecological Research ◽

Species Abundance Distributions ◽

Capture Recapture ◽

Using Data ◽

Removal Sampling

Measuring the abundance of individuals and the diversity of species are core components of most ecological research projects and conservation monitoring. This book brings together in one place, for the first time, the methods used to estimate the abundance of individuals in nature. The statistical basis of each method is detailed along with practical considerations for survey design and data collection. Methods are illustrated using data ranging from Alaskan shrubs to Yellowstone grizzly bears, not forgetting Costa Rican ants and Prince Edward Island lobsters. Where necessary, example code for use with the open source software R is supplied. When appropriate, reference is made to other widely used programs. After opening with a brief synopsis of relevant statistical methods, the first section deals with the abundance of stationary items such as trees, shrubs, coral, etc. Following a discussion of the use of quadrats and transects in the contexts of forestry sampling and the assessment of plant cover, there are chapters addressing line-intercept sampling, the use of nearest-neighbour distances, and variable sized plots. The second section deals with individuals that move, such as birds, mammals, reptiles, fish, etc. Approaches discussed include double-observer sampling, removal sampling, capture-recapture methods and distance sampling. The final section deals with the measurement of species richness; species diversity; species-abundance distributions; and other aspects of diversity such as evenness, similarity, turnover and rarity. This is an essential reference for anyone involved in advanced undergraduate or postgraduate ecological research and teaching, or those planning and carrying out data analysis as part of conservation survey and monitoring programmes.

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