scholarly journals Bait type affects fish assemblages and feeding guilds observed at baited remote underwater video stations

2013 ◽  
Vol 477 ◽  
pp. 189-199 ◽  
Author(s):  
J Wraith ◽  
T Lynch ◽  
TE Minchinton ◽  
A Broad ◽  
AR Davis
2017 ◽  
Vol 68 (7) ◽  
pp. 1391 ◽  
Author(s):  
D. Harasti ◽  
K. A. Lee ◽  
R. Laird ◽  
R. Bradford ◽  
B. Bruce

Stereo baited remote underwater video systems (stereo-BRUVs) are commonly used to assess fish assemblages and, more recently, to record the localised abundance and size of sharks. The present study investigated the occurrence and size of white sharks (Carcharodon carcharias) in the near-shore environment off Bennett’s Beach, part of a known nursery area for the species in central New South Wales, Australia. Six stereo-BRUV units were deployed approximately fortnightly between August and December 2015 for periods of 5h in depths of 7–14m. Stereo-BRUVs successfully recorded 34 separate sightings of 22 individual white sharks. The highest number of individuals detected during a single day survey was eight. All C. carcharias observed on stereo-BRUVs were juveniles ranging in size from 1.50 to 2.46-m total length (mean±s.e., 1.91±0.05m; n=22). The time to first appearance ranged from 15 to 299min (mean±s.e., 148±15min). This study demonstrates that the use of stereo-BRUVs is a viable, non-destructive method to obtain estimates of the size and presence of white sharks, and may be useful in estimating relative abundance in near-shore environments where white sharks are known to frequent.


2019 ◽  
Vol 70 (6) ◽  
pp. 870 ◽  
Author(s):  
Thomas M. Clarke ◽  
Sasha K. Whitmarsh ◽  
Peter G. Fairweather ◽  
Charlie Huveneers

Baited remote underwater video stations (BRUVS) are increasing in popularity as non-invasive and fishery-independent tools for assessing fish assemblages. Although most BRUVS studies have focused on benthic fish communities, recent studies also use BRUVS to examine the comparatively undersampled pelagic communities. However, the propensities of benthic BRUVS to detect pelagic fishes and, likewise, pelagic BRUVS to detect demersal fishes are unknown. This study simultaneously used benthic and pelagic BRUVS deployed either separately (single) or in combination to determine assemblages of demersal and pelagic species at three contrasting sites within temperate South Australia. Assemblages observed by benthic v. pelagic BRUVS differed significantly at all sites, including one as shallow as 7m deep, but there were no significant differences in assemblages observed between BRUVS of the same position (i.e. pelagic or benthic) when BRUVS were deployed as single units or in combination. This study reveals the limitations of using only benthic or pelagic BRUVS, and highlights the necessity for both BRUVS positions to be used together to ensure that a comprehensive representation of entire fish assemblages throughout the water column can be obtained.


2017 ◽  
Vol 68 (10) ◽  
pp. 1976
Author(s):  
Stephen Cousins ◽  
Mark J. Kennard ◽  
Brendan C. Ebner

The aim of the present study was to determine whether boat-based deployment of remote underwater video cameras is effective for surveying fish assemblages in the deepest reaches of two large tropical rivers in north-eastern Australia. In addition, we compared fish assemblages recorded on baited versus unbaited cameras, and evaluated the sampling effort (duration of recording) required to estimate fish assemblages using remote underwater videos. We found that fish assemblages differed according to the depth, with statistically significant differences largely attributable to the prevalence of small-bodied species (Ambassis sp., Melanotaenia sp. and Pseudomugil signifer recorded in shallow (0.4–2.0m) and intermediate (2.1–4.9m) depths, and larger-bodied fish species (>10cm TL), such as Lutjanus argentimaculatus, Mesopristes argenteus and Caranx sexfasciatus, in deep water (>5.0m). Estimates of fish assemblage attributes generally stabilised after 60min recording duration, suggesting that interrogation of video footage beyond this duration may not be cost-effective. We conclude that depth is an important consideration when surveying large and deep river fish assemblages and that where water clarity is favourable, underwater video provides one of the means by which an assemblage can be investigated across the entire depth profile.


Coral Reefs ◽  
2018 ◽  
Vol 37 (3) ◽  
pp. 659-673 ◽  
Author(s):  
Molly Moustaka ◽  
Tim J. Langlois ◽  
Dianne McLean ◽  
Todd Bond ◽  
Rebecca Fisher ◽  
...  

2015 ◽  
Vol 63 (2) ◽  
pp. 135-146 ◽  
Author(s):  
Dafne Marcelle de Almeida Ramos Campos ◽  
Adna Ferreira da Silva ◽  
Natalice dos Santos Sales ◽  
Ronnie Enderson Mariano Carvalho Cunha Oliveira ◽  
Andre Luiz Machado Pessanha

Abstract The present study on the temporal variations in diet and the trophic guilds of dominant fish species in a tidal mudflat, during the dry and rainy seasons. We aimed at classifying the diet composition of 17 species in the Mamanguape river estuary, northeastern Brazil, identifying the dominant food components and evaluating the effects of seasonality on the guild organization. Diet varied little between species and seasons; during the rainy season, the diets seemed to be more heterogeneous. According to the importance of prey in the diets, 5 primary feeding guilds were identified: (1) Detritivore, (2) Zooplanktivore, (3) Zoobenthivore-epifaune, (4) Zoobenthivore-infaune, and (5) Piscivore. Most fishes fed on a diverse range of food items but relied heavily on the zooplankton preys. Several fish species showed a tendency for a specialised diet, with almost all species showing some degree of opportunistic feeding. A high degree of diet overlap was found among some species; however, the presence of exploitative competition could not be determined.


2015 ◽  
Vol 63 (4) ◽  
pp. 429-442 ◽  
Author(s):  
Dafne Marcelle de Almeida Ramos Campos ◽  
Adna Ferreira da Silva ◽  
Natalice dos Santos Sales ◽  
Ronnie Enderson Mariano Carvalho Cunha Oliveira ◽  
Andre Luiz Machado Pessanha

Abstract The present study deals with the temporal variations in diet and the trophic guilds of dominant fish species on a tidal mudflat during the dry and rainy seasons. We sought to classify the diet composition of 17 species in the Mamanguape river estuary, northeastern Brazil, identifying the dominant food components and evaluating the effects of seasonality on the guild organization. Diets varied little between species and seasons, though they seemed to be more heterogeneous during the rainy season. Five primary feeding guilds were identified, in accordance with the importance of prey in the diets: (1) Detritivore, (2) Zooplanktivore, (3) Zoobenthivore-epifaune, (4) Zoobenthivore-infaune, and (5) Piscivore. Most fishes fed on a diverse range of food items but relied heavily on zooplankton prey. Several fish species showed a tendency to a specialised diet, with almost all species showing some degree of opportunistic feeding. A high degree of diet overlap was found among some species; however, the presence of exploitative competition could not be determined.


2017 ◽  
Vol 4 (1) ◽  
pp. 160645 ◽  
Author(s):  
Chouly Ou ◽  
Carmen G. Montaña ◽  
Kirk O. Winemiller

Body size is frequently claimed to be a major determinant of animal trophic interactions, yet few studies have explored relationships between body size and trophic interactions in rivers, especially within the tropics. We examined relationships between body size and trophic position (TP) within fish assemblages in four lowland rivers of the Lower Mekong Basin in Cambodia. Stable isotope analysis (based on δ 15 N) was used to estimate TP of common fish species in each river, and species were classified according to occupation of benthic versus pelagic habitats and major feeding guilds. Regression analysis yielded strong correlations between body size and TP among fishes from the Sesan and Sreprok rivers, but not those from the Mekong and Sekong rivers. The Mekong fish assemblage had higher average TP compared with those of other rivers. The relationship between body size and TP was positive and significantly correlated for piscivores and omnivores, but not for detritivores and insectivores. The body size–TP relationship did not differ between pelagic and benthic fishes. Body size significantly predicted TP within the orders Siluriformes and Perciformes, but not for Cypriniformes, the most species-rich and ecologically diverse order in the Lower Mekong River. We conclude that for species-rich, tropical fish assemblages with many detritivores and invertivores, body size would not be an appropriate surrogate for TP in food web models and other ecological applications.


Oceans ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 634-647
Author(s):  
Kara Noonan ◽  
Thomas Fair ◽  
Kristiaan Matthee ◽  
Kelsey Sox ◽  
Kylie Smith ◽  
...  

Throughout the Caribbean, coral reefs are transitioning from rugose, coral-dominated communities to flat, soft coral-dominated habitats, triggering declines in biodiversity. To help mitigate these losses, artificial structures have been used to re-create substrate complexity and support reef inhabitants. This study used natural and artificial structures to investigate the factors influencing the use of habitat by reef fish. During 2018 and 2019, divers added artificial structures and monitored the fish assemblages associating with both the artificial structures and naturally occurring corals. Overall, there were more fish on natural structures than on artificial structures. While structure shape did not influence fish use, there was a non-significant trend for increased use of larger structures. Fish observations did not differ across a gradient of shallow, complex reefs to deeper, flatter reefs; however, analyses of feeding guilds revealed clearer patterns: herbivores and omnivores were positively associated with low rugosity reefs where macroalgal abundance was higher, whereas invertivores preferred more rugose reefs. These results suggest that as reefs lose structural complexity, fish communities may become dominated by herbivores and omnivores. It also appears that the addition of artificial structures of the type used here may not mitigate the effects of structure loss on reef fish assemblages.


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