Development of a Video Trawl Survey System for New England Groundfish

DeCelles, Gregory R.; Keiley, Emily F.; Lowery, Travis M.; Calabrese, Nicholas M.; Stokesbury, Kevin D. E.

doi:10.1080/00028487.2017.1282888

Cited by 17 publications

(14 citation statements)

References 24 publications

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“…Failing to take these local differences into consideration can have consequences when trying to plan similar surveys when the target species may be affected by flow rates. Such camera surveys are often the most suitable method for monitoring marine reserves and areas closed to mobile fishing gears as they are considered both cost effective and noninvasive (Bouchet & Meeuwig, ; DeCelles, Keiley, Lowery, Calabrese, & Stokesbury, ). The need to consider detectability is therefore paramount to obtaining unbiased results.…”

Section: Discussionmentioning

confidence: 99%

Dynamic occupancy modeling of temperate marine fish in area‐based closures

Calvert

McGonigle

Sethi

et al. 2018

Ecology and Evolution

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Species distribution models (SDMs) are commonly used to model the spatial structure of species in the marine environment, however, most fail to account for detectability of the target species. This can result in underestimates of occupancy, where nondetection is conflated with absence. The site occupancy model (SOM) overcomes this failure by treating occupancy as a latent variable of the model and incorporates a detection submodel to account for variability in detection rates. These have rarely been applied in the context of marine fish and never for the multiseason dynamic occupancy model (DOM). In this study, a DOM is developed for a designated species of concern, cusk (Brosme brosme), over a four‐season period. Making novel use of a high‐resolution 3‐dimensional hydrodynamic model, detectability of cusk is considered as a function of current speed and algae cover. Algal cover on the seabed is measured from video surveys to divide the study area into two distinct regions: those with canopy forming species of algae and those without (henceforth bottom types). Modeled estimates of the proportion of sites occupied in each season are 0.88, 0.45, 0.74, and 0.83. These are significantly greater than the proportion of occupied sites measured from underwater video observations which are 0.57, 0.28, 0.43, and 0.57. Individual fish are detected more frequently with increasing current speed in areas lacking canopy and less frequently with increasing current speed in areas with canopy. The results indicate that, where possible, SDM studies for all marine species should take account of detectability to avoid underestimating the proportion of sites occupied at a given study area. Sampling closed areas or areas of conservation often requires the use of nonphysical, low impact sampling methods like camera surveys. These methods inherently result in detection probabilities less than one, an issue compounded by time‐varying features of the environment that are rarely accounted for marine studies. This work highlights the use of modeled hydrodynamics as a tool to correct some of this imbalance.

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Section: Discussionmentioning

confidence: 99%

Dynamic occupancy modeling of temperate marine fish in area‐based closures

Calvert

McGonigle

Sethi

et al. 2018

Ecology and Evolution

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“…This research was part of a larger experiment to test the use of video data to estimate groundfish abundance (detailed by DeCelles et al. and Stokesbury et al. ).…”

Section: Methodsmentioning

confidence: 99%

“…This research was part of a larger experiment to test the use of video data to estimate groundfish abundance (detailed by DeCelles et al 2017 andStokesbury et al 2017). The study area of 4,414 km 2 encompasses the southern portion of Georges Bank, including part of Closed Area II, and was selected based on the available observer data and the recent National Oceanic and Atmospheric Administration cooperative trawl survey station locations (Table 1, Figure 1; DeCelles et al 2014;Martin and Legault 2014).…”

Section: Methodsmentioning

confidence: 99%

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Windowpane Seasonal Distribution and Survey Availability on the Southern Portion of Georges Bank, USA

2019

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The Windowpane Scophthalmus aquosus stock in Georges Bank and the Gulf of Maine is considered overfished despite the lack of a directed fishery. Windowpane stocks are assessed using an index‐based method relying on the Northeast Fisheries Science Center's (NEFSC; National Oceanic and Atmospheric Administration) fall trawl survey. From 2013 to 2016, the School for Marine Science and Technology (SMAST; University of Massachusetts Dartmouth) conducted a fisheries‐independent trawl survey on the southern portion of Georges Bank, including part of Closed Area II. Using both the NEFSC and SMAST survey catches, we examined seasonal variations in CPUE of Windowpanes as well as their relationship with depth and temperature. Windowpane CPUE was significantly higher in the spring than in the fall and was linked with temperature changes. On the southern portion of Georges Bank, the NEFSC and SMAST surveys had similar relationships between Windowpane catch and temperature. In the spring, Windowpanes were abundant at water temperatures less than 7°C, and they moved out of the area as the temperature increased. In the fall, Windowpane CPUE was higher in warmer water temperatures and decreased as the temperature decreased. As Windowpanes moved out of the area, Fourspot Flounder Paralichthys oblongus replaced them in the habitat. This distribution pattern seems to occur across the whole stock. Our findings suggest that environmental factors can affect the CPUE indices from surveys that are assumed to be consistent, and this should be considered in future assessments.

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“…More sophisticated statistical analysis of video footages are under development in marine surveys field. Using deep learning to identify and quantify fish as they pass through the net [ 26 ], proposed to calculate absolute abundance estimate in trawls. A method for computing volumetric fish density using stereo cameras was also recently published by [ 27 ].…”

Section: Introductionmentioning

confidence: 99%

A methodological framework for characterizing fish swimming and escapement behaviors in trawls

et al. 2020

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Knowledge about fish behavior is crucial to be able to influence the capture process and catch species composition. The rapid expansion of the use of underwater cameras has facilitated unprecedented opportunities for studying the behavior of species interacting with fishing gears in their natural environment. This technological advance would greatly benefit from the parallel development of dedicated methodologies accounting for right-censored observations and variable observation periods between individuals related to instrumental, environmental and behavioral events. In this paper we proposed a methodological framework, based on a parametric Weibull mixture model, to describe the process of escapement attempts through time, test effects of covariates and estimate the probability that a fish will attempt to escape. We additionally proposed to better examine the escapement process at the individual level with regard to the temporal dynamics of escapement over time. Our approach was used to analyze gadoids swimming and escapement behaviors collected using a video set up in front of a selective device known to improve selectivity on gadoids in the extension of a bottom trawl. Comparison of the fit of models indicates that i) the instantaneous rate of escape attempts is constant over time and that the escapement process can be modelled using an exponential law; ii) the mean time before attempting to escape increases with the increasing number of attempts; iii) more than 80% of the gadoids attempted to escape through the selective device; and iv) the estimated probability of success was around 15%. Effects of covariates on the probability of success were investigated using binomial regression but none of them were significant. The data set collected is insufficient to make general statements, and further observations are required to properly investigate the effect of intrinsic and extrinsic factors governing gadoids behavior in trawls. This methodology could be used to better characterize the underlying behavioral process of fish in other parts of a bottom trawl or in relation to other fishing gears.

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Development of a Video Trawl Survey System for New England Groundfish

Cited by 17 publications

References 24 publications

Dynamic occupancy modeling of temperate marine fish in area‐based closures

Dynamic occupancy modeling of temperate marine fish in area‐based closures

Windowpane Seasonal Distribution and Survey Availability on the Southern Portion of Georges Bank, USA

A methodological framework for characterizing fish swimming and escapement behaviors in trawls

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