scholarly journals Ecological engineering across organismal scales: trophic-mediated positive effects of microhabitat enhancement on fishes

2020 ◽  
Vol 656 ◽  
pp. 181-192 ◽  
Author(s):  
D Taira ◽  
EC Heery ◽  
LHL Loke ◽  
A Teo ◽  
AG Bauman ◽  
...  
Keyword(s):  
Fish Assemblages ◽  
Ecological Engineering ◽  
Feeding Strategies ◽  
Underwater Video ◽  
Abiotic Conditions ◽  
Video Cameras ◽  
Positive Effects ◽  
Engineering Technique ◽  
Experimental Plots ◽  
Epilithic Algal Matrix

Retrofitting microhabitat features is a common ecological engineering technique for enhancing biodiversity and abundance of small, epilithic organisms on artificial shorelines by providing refuge spaces and/or ameliorating abiotic conditions. These features are typically too small to be utilised as refugia by larger, highly motile consumers such as fish, but they may affect these organisms through other mechanisms. This study sought to determine whether microhabitat enhancement units alter the fish abundance, richness and assemblage composition on tropical seawalls and explores possible underlying trophic mechanisms. We created 12 experimental plots consisting of 6 enhanced plots, each with 20 microhabitat enhancement tiles, and 6 control plots without tiles on intertidal seawalls at Pulau Hantu, an offshore island south of mainland Singapore. Benthic cover and fish assemblage were surveyed within each plot using photoquadrats and underwater video cameras, respectively, from April 2018 to February 2019. We found greater abundance and species richness and distinct assemblages of fish in the enhanced plots compared to the control plots. These differences were driven largely by an increase in both abundance and richness of fish species with epibenthic-feeding strategies and were significantly associated with higher biotic cover in the enhanced plots, especially epilithic algal matrix (EAM). Our results indicate that, in addition to facilitating epilithic organisms, microhabitat enhancement can provide food resources for epibenthic-feeding fishes, increase fish biodiversity, and alter fish assemblages in tropical urbanised shorelines.

Use of stereo baited remote underwater video systems to estimate the presence and size of white sharks (Carcharodon carcharias)

2017 ◽  
Vol 68 (7) ◽  
pp. 1391 ◽  
Author(s):  
D. Harasti ◽  
K. A. Lee ◽  
R. Laird ◽  
R. Bradford ◽  
B. Bruce
Keyword(s):  
Relative Abundance ◽  
Fish Assemblages ◽  
New South ◽  
Underwater Video ◽  
Carcharodon Carcharias ◽  
South Wales ◽  
Video Systems ◽  
Near Shore ◽  
Number Of Individuals ◽  
Non Destructive

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.

scholarly journals Coral settlement and recruitment responses to reef fish foraging and trait diversity

2021 ◽  
Author(s):  
Cher F Y Chow ◽  
Caitlin Bolton ◽  
Nader Boutros ◽  
Viviana Brambilla ◽  
Luisa Fontoura ◽  
...  
Keyword(s):  
Reef Fish ◽  
Fish Assemblages ◽  
Reef Fishes ◽  
Foraging Strategies ◽  
Coral Recruitment ◽  
Coral Settlement ◽  
Trait Divergence ◽  
Positive Effects ◽  
Recruitment Success ◽  
Trait Diversity

The process of coral recruitment is crucial to the healthy functioning of coral reef ecosystems, as well as recovery following disturbances. Fishes are key modulators of this process by feeding on algae and other benthic taxa that compete with corals for benthic space. However, foraging strategies within reef fish assemblages are highly diverse and the effect of foraging diversity on coral recruitment success remains poorly understood. Here, we test how the foraging traits of reef fishes affect coral settlement and juvenile success at Lizard Island, Great Barrier Reef. Using a multi-model inference approach incorporating six metrics of fish assemblage foraging diversity (foraging rates, trait richness, trait evenness, trait divergence, herbivore abundance, and benthic invertivore abundance), we found that herbivore abundance had positive effects on both coral settlement and recruitment success. However, foraging trait diversity had a negative effect on coral settlement but not on recruitment. Coral settlement was higher at sites with less trait diverse fish assemblages, specifically in trait divergence and richness. Moreover, these two trait diversity metrics were stronger predictors of coral settlement success compared to herbivore abundance. Our findings provide evidence that impacts mediated by fish foraging on coral juveniles can potentially be harmful during settlement, but the space-clearing effect overall remains advantageous. We show here that the variation of fish biodiversity across reefs can be a partial driver to spatially uneven patterns of coral recruitment and reef recovery.

scholarly journals An Estimation of Fish Biomass and Attached Organisms beneath Oyster Rafts in Hiroshima Bay, Japan

2021 ◽  
Vol 324 ◽  
pp. 03013
Author(s):  
Wahyudin Wahyudin ◽  
Tamiji Yamamoto
Keyword(s):  
Large Scale ◽  
Fish Habitat ◽  
Food Chains ◽  
Ecosystem Structure ◽  
Fish Production ◽  
Underwater Video ◽  
Oyster Culture ◽  
Video Cameras ◽  
Black Seabream ◽  
Material Cycles

Hiroshima Bays is top production approximately 60% of oyster production in Japan. For cultivate of oyster, fishermen use hanging rafts. A thousand of raft is hanging during 2-3 years in the bay. Large-scale oyster culture may change the ecosystem structure and material cycles in the bay through the filtration of particulate matter by oysters and other associated animals. This study described the community structure of marine organisme in terms of fishes surrounding and animal attached on oyster rafts. Field observation was carried out from 2016 to 2019 at oyster farming in Hiroshima Bay. Oyster production and provisioning for the fish habitat were also evaluated by placing underwater video cameras beneath oyster culture rafts. The result showed that black seabream was high biomass and oyster it shelf was bigger bioyster for animal attached on oyster raft. The number of individual, mussel is most abundance of animal attach on oyster raft with ratio 9:1 than number of oyster. Maintaining oyster culture is important not only for maintaining oyster production, but also for maintaining fish production by enhancing material cycles through the paths in the food chains of Hiroshima Bay under oligotrophic conditions.

Overlap in fish assemblages observed using pelagic and benthic baited remote underwater video stations

2019 ◽  
Vol 70 (6) ◽  
pp. 870 ◽  
Author(s):  
Thomas M. Clarke ◽  
Sasha K. Whitmarsh ◽  
Peter G. Fairweather ◽  
Charlie Huveneers
Keyword(s):  
Water Column ◽  
Fish Assemblages ◽  
South Australia ◽  
Single Units ◽  
Benthic Fish ◽  
Underwater Video ◽  
Pelagic Species ◽  
Non Invasive ◽  
Pelagic Fishes ◽  
Pelagic Communities

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.

Corrigendum to: Depth-related composition and structuring of tropical riverine fish assemblages revealed by baited video

2017 ◽  
Vol 68 (10) ◽  
pp. 1976
Author(s):  
Stephen Cousins ◽  
Mark J. Kennard ◽  
Brendan C. Ebner
Keyword(s):  
Fish Assemblages ◽  
Cost Effective ◽  
Water Clarity ◽  
Sampling Effort ◽  
Underwater Video ◽  
Video Footage ◽  
Eastern Australia ◽  
North Eastern ◽  
Lutjanus Argentimaculatus ◽  
Riverine Fish

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.

New topics and limits related to the use of beneficial microbes in pig feeding

2010 ◽  
Vol 1 (4) ◽  
pp. 447-454 ◽  
Author(s):  
P. Bosi ◽  
P. Trevisi
Keyword(s):  
Immune Response ◽  
Feeding Strategies ◽  
Neonatal Pigs ◽  
Positive Effects ◽  
Adhesion Sites ◽  
Young Pigs ◽  
Weaning Stress ◽  
Gut Mucosa ◽  
Weaning Piglets

Reports highlighting the positive effects of probiotics on the performance of pigs or on in vitro traits are now quite frequent, but the use of probiotics in feed compounds has not been widespread. Prerequisites for the healthy and efficient growth of young pigs are the rapid maturation of the gut mucosa and the mucosa-associated lymphoid tissue, and the formation of a local stable and complex bacterial community. In neonatal pigs, suckling and the maternal environment shape the gut microbiota. Later, when weaning stress causes a transient drop in favourable bacteria, the oral supply of microbes could contribute to re-establish the microbiota balance. Some strains isolated from piglets were tested for their ability to settle in the intestine. After weaning, piglets experience new and often unfavourable bacteria. Probiotics have been investigated to contrast the enteropathogens, owing to their properties (production of antibacterial molecules, competition on adhesion sites, stimulation of immune response, etc.). Data in general show that their oral administration can be favourable or, at least, innocuous. However, two cases are presented here, where a probiotic given to pigs already combating enteropathogens impaired pig health, and this could be explained by their effect on the immune response. A more tolerogenic response of the host is expected when beneficial bacteria directly contrast the pathogens, probiotics are claimed to directly modulate or even activate the immune system. For one probiotic divergent effects on growth and health are presented, and these differences may be due to different experimental details or different starting microbiological environments. Scarce data are available on specific immune responses induced by commensal microbes in pigs, and on the interaction of resident microbiota with orally supplied probiotics. Increased knowledge of the role of commensal microbiota in the gut and in the pig metabolism, helps in selecting the best bacteria and in designing the best feeding strategies for improving the efficacy and the reliability of their oral use.

scholarly journals The germination niches of grassland species targeted for restoration: effects of seed pre-treatments

2011 ◽  
Vol 21 (2) ◽  
pp. 117-131 ◽  
Author(s):  
Markus Wagner ◽  
Richard F. Pywell ◽  
Tatjana Knopp ◽  
James M. Bullock ◽  
Matthew S. Heard
Keyword(s):  
Light Availability ◽  
Seed Priming ◽  
Calcareous Grassland ◽  
Species Introduction ◽  
Abiotic Conditions ◽  
Grassland Species ◽  
Positive Effects ◽  
Pre Treatment ◽  
Species Specific ◽  
Germination Niche

AbstractRestoration of semi-natural grassland communities involves a combination of (1) sward disturbance to create a temporal window for establishment, and (2) target species introduction, the latter usually by seed sowing. With great regularity, particular species establish only poorly. More reliable establishment could improve outcome of restoration projects and increase cost-effectiveness. We investigated the abiotic germination niche of ten poorly establishing calcareous grassland species by simultaneously exploring the effects of moisture and light availability and temperature fluctuation on percentage germination and speed of germination. We also investigated the effects of three different pre-treatments used to enhance seed germination – cold-stratification, osmotic priming and priming in combination with gibberellic acid (GA3) – and how these affected abiotic germination niches. Species varied markedly in width of abiotic germination niche, ranging from Carex flacca with very strict abiotic requirements, to several species reliably germinating across the whole range of abiotic conditions. Our results suggest pronounced differences between species in gap requirements for establishment. Germination was improved in most species by at least one pre-treatment. Evidence for positive effects of adding GA3 to seed priming solutions was limited. In several species, pre-treated seeds germinated under a wider range of abiotic conditions than untreated seeds. Improved knowledge of species-specific germination niches and the effects of seed pre-treatments may help to improve species establishment by sowing, and to identify species for which sowing at a later stage of restoration or introduction as small plants may represent a more viable strategy.

scholarly journals Using underwater video to evaluate the performance of the Fukui trap as a mitigation tool for the invasive European green crab (Carcinus maenas) in Newfoundland, Canada

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4223 ◽  
Author(s):  
Jonathan A. Bergshoeff ◽  
Cynthia H. McKenzie ◽  
Kiley Best ◽  
Nicola Zargarpour ◽  
Brett Favaro
Keyword(s):  
West Coast ◽  
Carcinus Maenas ◽  
Green Crab ◽  
Underwater Video ◽  
Catch Per Unit Effort ◽  
Video Cameras ◽  
Nearshore Ecosystems ◽  
European Green Crab ◽  
Rate Of Success

The European green crab (Carcinus maenas) is a destructive marine invader that was first discovered in Newfoundland waters in 2007 and has since become established in nearshore ecosystems on the south and west coast of the island. Targeted fishing programs aimed at removing green crabs from invaded Newfoundland ecosystems use Fukui traps, but the capture efficiency of these traps has not been previously assessed. We assessed Fukui traps usingin situobservation with underwater video cameras as they actively fished for green crabs. From these videos, we recorded the number of green crabs that approached the trap, the outcome of each entry attempt (success or failure), and the number of exits from the trap. Across eight videos, we observed 1,226 green crab entry attempts, with only a 16% rate of success from these attempts. Based on these observations we believe there is scope to improve the performance of the Fukui trap through modifications in order to achieve a higher catch per unit effort (CPUE), maximizing trap usage for mitigation. Ultimately, a more efficient Fukui trap will help to control green crab populations in order to preserve the function and integrity of ecosystems invaded by the green crab.

Sign in / Sign up

Export Citation Format

Share Document