scholarly journals The use of singlebeam echo‐sounder depth data to produce demersal fish distribution models that are comparable to models produced using multibeam echo‐sounder depth

2021 ◽  
Author(s):  
Marcela Montserrat Landero Figueroa ◽  
Miles J. G. Parsons ◽  
Benjamin J. Saunders ◽  
Ben Radford ◽  
Chandra Salgado‐Kent ◽  
...  
Keyword(s):  
Demersal Fish ◽  
Fish Distribution ◽  
Distribution Models ◽  
Depth Data ◽  
Echo Sounder

scholarly journals The use of singlebeam echo-sounder depth data to produce demersal fish distribution models that are comparable to models produced using multibeam echo-sounder depth

2021 ◽  
Author(s):  
Marcela Montserrat Landero Figueroa ◽  
Miles Parsons ◽  
Benjamin Saunders ◽  
Ben Radford ◽  
Chandra Salgado-Kent ◽  
...  
Keyword(s):  
High Resolution ◽  
Demersal Fish ◽  
Important Variable ◽  
Fish Distribution ◽  
Slope Aspect ◽  
Distribution Models ◽  
Explanatory Variables ◽  
Continuous Map ◽  
Spatial Coverage ◽  
Echo Sounder

Seafloor characteristics can help in the prediction of fish distribution, which is required for fisheries and conservation management. Despite this, only 5-10% of the world’s seafloor has been mapped at high resolution as it is a time-consuming and expensive process. Multibeam echo-sounders (MBES) can produce high-resolution bathymetry and a broad swath coverage of the seafloor, but require greater financial and technical resources for operation and data analysis than singlebeam echo-sounders (SBES). In contrast, SBES provide comparatively limited spatial coverage, as only a single measurement is made from directly under the vessel. Thus, producing a continuous map requires interpolation to fill gaps between transects. This study assesses the performance of demersal fish species distribution models by comparing those derived from interpolated SBES data with full-coverage MBES distribution models. A Random Forest classifier was used to model the distribution of Abalistes stellatus, Gymnocranius grandoculis, Lagocephalus sceleratus, Loxodon macrorhinus, Pristipomoides multidens and Pristipomoides typus, with depth and depth derivatives (slope, aspect, standard deviation of depth, terrain ruggedness index, mean curvature and topographic position index) as explanatory variables. The results indicated that distribution models for A. stellatus, G. grandoculis, L. sceleratus, and L. macrorhinus performed poorly for MBES and SBES data with Area Under the Receiver Operator Curves (AUC) below 0.7. Consequently, the distribution of these species could not be predicted by seafloor characteristics produced from either echo-sounder type. Distribution models for P. multidens and P. typus performed well for MBES and the SBES data with an AUC above 0.8. Depth was the most important variable explaining the distribution of P. multidens and P. typus in both MBES and SBES models. While further research is needed, this study shows that in resource-limited scenarios, SBES can produce comparable results to MBES for use in demersal fish management and conservation.

scholarly journals Testing the Improvement of Coral Reef Associated Fish Distribution Models Based on Multibeam Bathymetry by Adding Seafloor Backscatter Data

2021 ◽  
Vol 8 ◽  
Author(s):  
Marcela Montserrat Landero Figueroa ◽  
Miles J. G. Parsons ◽  
Benjamin J. Saunders ◽  
Ben Radford ◽  
Iain M. Parnum
Keyword(s):  
Strong Relationship ◽  
Demersal Fish ◽  
Important Variable ◽  
Acoustic Energy ◽  
Fish Distribution ◽  
Distribution Models ◽  
Seafloor Morphology ◽  
Seafloor Backscatter ◽  
Using Data ◽  
Lagocephalus Sceleratus

Demersal fishes constitute an essential component of the continental shelf ecosystem, and a significant element of fisheries catch around the world. However, collecting distribution and abundance data of demersal fish, necessary for their conservation and management, is usually expensive and logistically complex. The increasing availability of seafloor mapping technologies has led to the opportunity to exploit the strong relationship demersal fish exhibit with seafloor morphology to model their distribution. Multibeam echo-sounder (MBES) systems are a standard method to map seafloor morphology. The amount of acoustic energy reflected by the seafloor (backscatter) is used to estimate specific characteristics of the seafloor, including acoustic hardness and roughness. MBES data including bathymetry and depth derivatives were used to model the distribution of Abalistes stellatus, Gymnocranius grandoculis, Lagocephalus sceleratus, Lethrinus miniatus, Loxodon macrorhinus, Lutjanus sebae, and Scomberomorus queenslandicus. The possible improvement of model accuracy by adding the seafloor backscatter was tested in three different areas of the Ningaloo Marine Park off the west coast of Australia. For the majority of species, depth was a primary variable explaining their distribution in the three study sites. Backscatter was identified to be an important variable in the models, but did not necessarily lead to a significant improvement in the demersal fish distribution models’ accuracy. Possible reasons for this include: the depth and derivatives were capturing the significant changes in the habitat, or the acoustic data collected with a high-frequency MBES were not capturing accurately relevant seafloor characteristics associated with the species distribution. The improvement in the accuracy of the models for certain species using data already available is an encouraging result, which can have a direct impact in our ability to monitor these species.

Distribution, biomass and community structure of demersal fishes of the Gulf of Carpentaria, Australia

1994 ◽  
Vol 45 (3) ◽  
pp. 375 ◽  
Author(s):  
SJM Blaber ◽  
DT Brewer ◽  
AN Harris
Keyword(s):  
Community Structure ◽  
Abiotic Factors ◽  
Fish Fauna ◽  
Distribution Patterns ◽  
Demersal Fish ◽  
Fish Distribution ◽  
Sediment Type ◽  
Principal Coordinates Analysis ◽  
Main Site ◽  
Principal Coordinates

The demersal fish fauna of the Gulf of Carpentaria was surveyed during November and December 1990. Over 300 species from 85 families were caught by trawling a systematic grid of 107 stations. The absolute mean biomass was 124.8 kg ha-1 (s.e. =44.1) for day trawls and 53.7 kg ha-1 (s.e. =6.0) for night trawls. The overall mean catch rates were 421.3 kg h-1 (s.e. = 128.5) for day trawls and 198.6 kg h-1 (s.e. =21.5) for night trawls. Biomasses were twice as high in the prawn-trawling grounds of Albatross Bay, the south-eastern gulf and Groote Eylandt as they were elsewhere in the gulf. Twenty-five species made up 75% of the biomass; the dominant families were Haemulidae, Carangidae, Leiognathidae and Nemipteridae. Community-structure and distribution patterns were analysed by numerical classification techniques and principal-coordinates analysis. These indicated six main site groups and 15 fish community groups, based on fish species occurrences and biomasses. There was a relationship between fish distribution patterns and depth of water but not other abiotic factors recorded (sediment type, salinity, temperature and turbidity).

Diversity, relative abundance, new locality records, and updated fish fauna of the Ross Sea region

2013 ◽  
Vol 25 (5) ◽  
pp. 619-636 ◽  
Author(s):  
Stuart M. Hanchet ◽  
Andrew L. Stewart ◽  
Peter J. McMillan ◽  
Malcolm R. Clark ◽  
Richard L. O'Driscoll ◽  
...  
Keyword(s):  
Ross Sea ◽  
Fish Fauna ◽  
Demersal Fish ◽  
Fish Distribution ◽  
Distribution Data ◽  
Mesopelagic Fish ◽  
Species List ◽  
The North ◽  
Evenness Indices ◽  
Total Species

AbstractTwo surveys were carried out in the Ross Sea region during February and March 2004 and 2008 from the New Zealand RVTangaroa. Fishes were sampled on the continental shelf and slope of the Ross Sea, and on adjacent seamounts to the north, mainly using a large demersal fish trawl and a large mesopelagic fish trawl. Parts of the shelf and slope were stratified by depth and at least three random demersal trawls were completed in each stratum, enabling biomass estimates of demersal fish to be calculated. Fish distribution data from these two surveys were supplemented by collections made by observers from the toothfish fishery. A diverse collection of over 2500 fish specimens was obtained from the two surveys representing 110 species in 21 families. When combined with previous documented material this gave a total species list of 175, of which 135 were from the Ross Sea shelf and slope (to the 2000 m isobath). Demersal species-richness, diversity and evenness indices all decreased going from the shelf to the slope and the seamounts. In contrast, indices for pelagic species were similar for the slope and seamounts/abyss but were much lower for the shelf.

Limitations of biophysical habitats as biodiversity surrogates in the Hauraki Gulf Marine Park

2016 ◽  
Vol 22 (2) ◽  
pp. 159 ◽  
Author(s):  
Susan E. Jackson ◽  
Carolyn J. Lundquist
Keyword(s):  
Marine Protected Areas ◽  
Demersal Fish ◽  
Strongly Correlated ◽  
Distribution Models ◽  
Biodiversity Protection ◽  
Biodiversity Surrogates ◽  
Marine Park ◽  
Habitat Classification ◽  
Data Layers ◽  
Further Development

The Hauraki Gulf Marine Park (HGMP) is recognised for its diverse natural environment and associated biodiversity, as well as the extensive social, cultural and economic values derived therein. Here, we evaluate the current level of biodiversity protection provided by existing Marine Protected Areas (MPAs) within the HGMP. We use abiotic datasets to develop a habitat classification system to identify the suite of biophysical habitats found in the Marine Park, and their relative protection within existing MPAs (both no-take marine reserves and Cable Protection Zones). Our analysis demonstrated that half of the biophysical habitats identified in the HGMP are not currently afforded protection within MPAs, and that biophysical classifications poorly differentiate across subtidal, soft-sediment habitats using available data layers. We then evaluated representation of these environmental surrogates within a biodiversity prioritisation analysis based on distribution models for demersal fish species. Biophysical habitat surrogates showed poor representation across habitats within highest-priority areas based on prioritisations of demersal fish biodiversity. This suggests the need for further development of biophysical habitat surrogates that are more strongly correlated with biodiversity, if they are to be used to inform biodiversity protection in the HGMP.

scholarly journals Accounting for detectability in fish distribution models: an approach based on time-to-first-detection

2015 ◽  
Vol 2 ◽  
Author(s):  
Ferreira Mário ◽  
Filipe Ana Filipa ◽  
Magalhães Filomena ◽  
Beja Pedro
Keyword(s):  
Fish Distribution ◽  
Distribution Models

scholarly journals Random forests to evaluate biotic interactions in fish distribution models

2015 ◽  
Vol 67 ◽  
pp. 173-183 ◽  
Author(s):  
P. Vezza ◽  
R. Muñoz-Mas ◽  
F. Martinez-Capel ◽  
A. Mouton
Keyword(s):  
Random Forests ◽  
Biotic Interactions ◽  
Fish Distribution ◽  
Distribution Models

Anadromous Sturgeons: Habitats, Threats, and Management

2007 ◽  
Keyword(s):  
Sand Dunes ◽  
Demersal Fish ◽  
Lake Sturgeon ◽  
Fish Distribution ◽  
Trawl Survey ◽  
Atlantic Sturgeon ◽  
Potential Threat ◽  
Two Phase ◽  
Good Correspondence ◽  
Acoustic Surveys

Abstract.—Atlantic sturgeon <em>Acipenser oxyrinchus</em> and lake sturgeon <em>A. fulvescens </em>in the middle St. Lawrence estuary are under consideration for designation as “endangered” or “vulnerable” species. A potential threat to these species is the disposal of dredged sediments in an area where young-of-the-year and juvenile Atlantic sturgeon concentrate. The objectives of this study were (1) to study the short-term and cumulative impacts, if any, of the dumped sediments on the abundance, distribution, and movements of the two sturgeon species downstream of the disposal area, and (2) to investigate the usefulness of acoustic surveys for assessing sturgeon density and distribution. A two-phase, combined acoustic-trawl survey was conducted to describe sturgeon distributions and produce concurrent acoustic and trawl estimates of the relative abundance of demersal fish within the area (lake sturgeon and Atlantic sturgeon were presumed to dominate the acoustic echoes). This series of surveys was the first known attempt to quantify sturgeon abundance and distribution with a vertically deployed echo sounder. The results showed good correspondence between the two methods. Replicated sampling also showed the repeatability of the acoustic technique and stability in demersal fish distribution on a scale of days. The acoustic surveys indicated that the spatial distribution of demersal fishes was dependent on substrate, as these fishes avoided areas of dredged sediment dumping and associated sand dunes. Our study showed that under certain conditions, acoustic-trawl surveys can reliably assess sturgeon density and distribution.

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