Spatial relationships and temporal variability in a littoral macrophyte fish assemblage

2004 ◽  
Vol 55 (6) ◽  
pp. 609 ◽  
Author(s):  
S. R. Balcombe ◽  
G. P. Closs
Keyword(s):  
Fish Assemblages ◽  
Temporal Dynamics ◽  
Juvenile Fish ◽  
Physical Structure ◽  
First Year ◽  
Small Fish ◽  
Spatial And Temporal Patterns ◽  
Emergent Macrophytes ◽  
Spatial And Temporal Dynamics ◽  
Fish Traps

The presence of macrophytes in lentic systems often exerts a large influence on the spatial and temporal dynamics of the small-bodied fish that inhabit them, particularly in the presence of piscivorous predators. To examine spatial and temporal patterns of fish abundance in macrophyte stands we sampled fish bimonthly with fine-meshed fish traps by day and night in giant rush habitats of a River Murray billabong between October 1995 and September 1996. Three native and three exotic species were found within these habitats during the study, however, catches were dominated by two species of native carp gudgeons (Hypseleotris spp.). Consistently higher numbers of gudgeons were trapped during the day than at night throughout the study period and there was a sustained decline in catch from spring in the first year to the following spring. The results suggest recruitment of juvenile fish spawned during the summer was insufficient for relative abundance to return to the high numbers found at the start of the study. Fine-scale distribution of carp gudgeons within emergent macrophytes was not generally explained by variability in either physical structure or physicochemical variability. This contrasts with many studies of small fish assemblages in macrophytes where piscivorous predators are present.

scholarly journals Using social media to quantify spatial and temporal dynamics of nature-based recreational activities

2016 ◽  
Author(s):  
Francesca Mancini ◽  
George M. Coghill ◽  
David Lusseau
Keyword(s):  
Temporal Dynamics ◽  
Spatial And Temporal Patterns ◽  
National Scale ◽  
Great Opportunity ◽  
Spatial And Temporal Scales ◽  
Use Of Data ◽  
Spatial And Temporal Dynamics ◽  
Recent National Survey ◽  
Visitor Numbers

AbstractBig data offer a great opportunity for nature-based recreation (NbR) mapping and evaluation. However, it is important to determine when and how it is appropriate to use this resource. We used Scotland as a case study to validate the use of data from Flickr as an indicator of NbR on a national scale and at several regional spatial and temporal resolutions. We compared Flickr photographs to visitor statistics in the Cairngorms National Park (CNP) and determined whether temporal variability in photo counts could be explained by known annual estimates of CNP visitor numbers. We then used a unique recent national survey of nature recreation in Scotland to determine whether the spatial distribution of Flickr photos could be explained by known spatial variability in nature use. Following this validation work, we used Flickr data to identify hotspots of wildlife watching in Scotland and investigated how they changed between 2005 and 2015.We found that spatial and temporal patterns in Flickr count are explained by measures of visitation obtained through surveys and that this relationship is reliable down to a 10 Km scale resolution. Our findings have implications for planning and management of NbR as they suggest that photographs uploaded on Flickr reflect patterns of NbR at spatial and temporal scales that are relevant for ecosystem management.

scholarly journals Patterns of small fish distributions in seagrass beds in a temperate Australian estuary

2007 ◽  
Vol 87 (5) ◽  
pp. 1297-1307 ◽  
Author(s):  
Jane E. Jelbart ◽  
Pauline M. Ross ◽  
Rod M. Connolly
Keyword(s):  
Fish Species ◽  
Fish Assemblages ◽  
Juvenile Fish ◽  
Small Fish ◽  
Seagrass Beds ◽  
Estuary Mouth ◽  
Seagrass Cover ◽  
Australian Estuary ◽  
Continuous Beds ◽  
Zostera Capricorni

Beds of the seagrass Zostera capricorni are an integral part of the estuarine landscape along the east coast of Australia, forming an important habitat for juvenile fish. Seagrass beds can vary in their size, shape and patchiness of seagrass cover as well as their distance from the estuary mouth. We tested for a correlation between these features and small fish assemblages in seagrass. Fifteen beds were selected from three size-categories (small, 980 to 2300 m2; medium, 3375 to 4090 m2; and large, 5335 to 6630 m2). We found that the size of beds, the patchiness of seagrass cover and location within the estuary (distance from estuary mouth) were all related to differences in fish assemblages. There were greater densities of fish species in small (10.3 ±0.79 species .net-1) compared to medium (7.6 ±0.6) and large (8.2 ±0.5) beds. This occurred regardless of bed placement within the estuary, its patchiness or time of sampling (day and night). The fish assemblages within seagrass beds also changed as bed distance to estuary mouth increased. Six species had greater densities in beds closer to the estuary mouth, while only two species were in greater densities far from the mouth. Fish assemblages were different between beds with patchy and continuous cover, although total densities of all fish species combined were similar. There were greater densities of four species in continuous beds compared to two species that were greater in patchy beds. Overall, an important finding was that even small patchy seagrass beds contain greater densities of small fish species than larger beds with continuous seagrass cover.

scholarly journals Spatial and Temporal Patterns in Volunteer Data Contribution Activities: A Case Study of eBird

2020 ◽  
Vol 9 (10) ◽  
pp. 597
Author(s):  
Guiming Zhang
Keyword(s):  
Temporal Dynamics ◽  
Bird Species ◽  
Temporal Patterns ◽  
Volunteered Geographic Information ◽  
Geographic Information ◽  
Spatial And Temporal Patterns ◽  
Space And Time ◽  
Spatial And Temporal Dynamics ◽  
The World

Volunteered geographic information (VGI) has great potential to reveal spatial and temporal dynamics of geographic phenomena. However, a variety of potential biases in VGI are recognized, many of which root from volunteer data contribution activities. Examining patterns in volunteer data contribution activities helps understand the biases. Using eBird as a case study, this study investigates spatial and temporal patterns in data contribution activities of eBird contributors. eBird sampling efforts are biased in space and time. Most sampling efforts are concentrated in areas of denser populations and/or better accessibility, with the most intensively sampled areas being in proximity to big cities in developed regions of the world. Reported bird species are also spatially biased towards areas where more sampling efforts occur. Temporally, eBird sampling efforts and reported bird species are increasing over the years, with significant monthly fluctuations and notably more data reported on weekends. Such trends are driven by the expansion of eBird and characteristics of bird species and observers. The fitness of use of VGI should be assessed in the context of applications by examining spatial, temporal and other biases. Action may need to be taken to account for the biases so that robust inferences can be made from VGI observations.

scholarly journals An experimental evaluation of the effect of escape gaps on the quantity, diversity, and size of fish caught in traps in Montserrat

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261119
Author(s):  
Jason Flower ◽  
Andy Estep ◽  
Keinan James ◽  
Robin Ramdeen ◽  
Claire A. Runge ◽  
...  
Keyword(s):  
Fish Species ◽  
Diversity Index ◽  
Juvenile Fish ◽  
Fish Length ◽  
Small Fish ◽  
Mixed Effect ◽  
Fish Traps ◽  
Total Fish ◽  
The Mean ◽  
The Caribbean

Coral reef fisheries are vital to the livelihoods of millions of people worldwide but are challenging to manage due to the high diversity of fish species that are harvested and the multiple types of fishing gear that are used. Fish traps are a commonly used gear in reef fisheries in the Caribbean and other regions, but they have poor selectivity and frequently capture juvenile fish, impacting the sustainability of the fishery. One option for managing trap fisheries is the addition of escape gaps, which allow small fish to escape. We compared catches of traps with and without two 2.5 cm (1 inch) escape gaps on the Caribbean island of Montserrat. No significant differences were found in the mean fish length, total fish biomass, number of fish, fish species richness, and Shannon diversity index between hauls of the two trap designs, though traps with escape gaps did catch larger proportions of wider-bodied fish and smaller proportions of narrow-bodied fish. Furthermore, traps with gaps caught a smaller proportion of small-sized fish and fewer immature fish (though differences were not statistically significant). Linear mixed effect models predict that soak time (the length of time between trap hauls) increases the mean catch length, total catch biomass and total number of species in the catch. The relatively modest evidence for the effect of the gaps on catch may be explained by the long soak times used, which could have allowed most smaller-sized fish to escape or be consumed by larger individuals before hauling in both traps with and without escape gaps. Despite the small differences detected in this study, escape gaps may still offer one of the best options for improving sustainability of catches from fish traps, but larger escape gaps should be tested with varying soak times to determine optimum escape gap size.

Spatial and temporal dynamics of temperate Australian rockpool ichthyofaunas

2003 ◽  
Vol 54 (2) ◽  
pp. 163 ◽  
Author(s):  
Shane P. Griffiths
Keyword(s):  
Fish Assemblages ◽  
Temporal Dynamics ◽  
New South ◽  
Common Species ◽  
Spatial And Temporal Variation ◽  
Future Research ◽  
Fish Assemblage Structure ◽  
Intertidal Environment ◽  
South Wales ◽  
Spatial And Temporal Dynamics

Spatial and temporal variation, and factors influencing the structure of intertidal rockpool fish assemblages were quantitatively investigated at three large rocky headlands in south-eastern New South Wales, Australia. A total of 5244 fish from 46 species, mainly permanent intertidal residents from the families Clinidae, Blenniidae, Tripterygiidae, Gobiidae, Gobiesocidae and Girellidae, was caught in the rockpools. Numbers of species and individuals and dominance patterns of species showed significant variability within locations, possibly in response to variations in rockpool tidal height and volume, or environmental variables, such as temperature and dissolved oxygen. Species composition also differed among locations, probably as a result of availability of different habitats at each location, which may be preferred by different species. Fish assemblage structure was stable and persistent through time, presumably because rockpools are colonized only by species suitably adapted to the dynamic intertidal environment. Temporal variability in the abundance of some common species occurred during summer and autumn, mainly owing to recruitment of resident fishes. Directions for future research are given, which may contribute to an understanding of the processes that underpin these patterns.

Are spatial and temporal patterns in Lynn Canal overwintering Pacific herring related to top predator activity?

2016 ◽  
Vol 73 (9) ◽  
pp. 1307-1318 ◽  
Author(s):  
Kevin M. Boswell ◽  
Guillaume Rieucau ◽  
Johanna J. Vollenweider ◽  
John R. Moran ◽  
Ron A. Heintz ◽  
...  
Keyword(s):  
Water Column ◽  
Temporal Dynamics ◽  
Winter Season ◽  
Humpback Whales ◽  
Pacific Herring ◽  
Spatial And Temporal Patterns ◽  
Southeast Alaska ◽  
Avian Predators ◽  
Spatial And Temporal Dynamics ◽  
Feeding Activities

In Southeast Alaska, overwintering Pacific herring (Clupea pallasii) form large conspicuous schools that are preyed upon by an abundance of mammalian and avian predators, thus leading to the question of why herring adopt a strategy that appears counterproductive to predator avoidance during these periods. We examined the spatial and temporal dynamics of overwintering Pacific herring and associations with predators through monthly hydroacoustic surveys during two consecutive winters. Large variation was observed through the winter season in herring distribution, school morphology, and density. Herring school characteristics and biomass estimates were negatively correlated with humpback whale (Megaptera novaeangliae) abundance patterns during both winters, and as whales departed towards the end of winter, herring distributions shifted from dispersed schools in the water column toward deep, dense schools. We postulate that the schooling patterns observed in Lynn Canal overwintering herring are likely to be mediated by predation threat rather than energetics or feeding activities. An additional consequence of humpback whales dispersing herring in the water column may be an increased threat of predation by other surface-oriented predators.

Spatial and temporal dynamics of lexico-semantic processing in American Sign Language

2011 ◽  
Author(s):  
M. Leonard ◽  
N. Ferjan Ramirez ◽  
C. Torres ◽  
M. Hatrak ◽  
R. Mayberry ◽  
...  
Keyword(s):  
American Sign Language ◽  
Sign Language ◽  
Semantic Processing ◽  
Temporal Dynamics ◽  
American Sign ◽  
Spatial And Temporal Dynamics

Spatial and temporal dynamics of Pacific capelin Mallotus catervarius in the Gulf of Alaska: implications for ecosystem-based fisheries management

2020 ◽  
Vol 637 ◽  
pp. 117-140 ◽  
Author(s):  
DW McGowan ◽  
ED Goldstein ◽  
ML Arimitsu ◽  
AL Deary ◽  
O Ormseth ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Marine Ecosystem ◽  
Gulf Of Alaska ◽  
Data Series ◽  
Limited Information ◽  
Important Species ◽  
Multiple Data ◽  
Spatial And Temporal Dynamics ◽  
Spawning Areas ◽  
Spatio Temporal

Pacific capelin Mallotus catervarius are planktivorous small pelagic fish that serve an intermediate trophic role in marine food webs. Due to the lack of a directed fishery or monitoring of capelin in the Northeast Pacific, limited information is available on their distribution and abundance, and how spatio-temporal fluctuations in capelin density affect their availability as prey. To provide information on life history, spatial patterns, and population dynamics of capelin in the Gulf of Alaska (GOA), we modeled distributions of spawning habitat and larval dispersal, and synthesized spatially indexed data from multiple independent sources from 1996 to 2016. Potential capelin spawning areas were broadly distributed across the GOA. Models of larval drift show the GOA’s advective circulation patterns disperse capelin larvae over the continental shelf and upper slope, indicating potential connections between spawning areas and observed offshore distributions that are influenced by the location and timing of spawning. Spatial overlap in composite distributions of larval and age-1+ fish was used to identify core areas where capelin consistently occur and concentrate. Capelin primarily occupy shelf waters near the Kodiak Archipelago, and are patchily distributed across the GOA shelf and inshore waters. Interannual variations in abundance along with spatio-temporal differences in density indicate that the availability of capelin to predators and monitoring surveys is highly variable in the GOA. We demonstrate that the limitations of individual data series can be compensated for by integrating multiple data sources to monitor fluctuations in distributions and abundance trends of an ecologically important species across a large marine ecosystem.

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