scholarly journals The relationships of seabird assemblages to physical habitat features in Pacific equatorial waters during spring 1984–1991

1997 ◽  
Vol 54 (4) ◽  
pp. 593-599 ◽  
Author(s):  
C Ribic
Keyword(s):  
Physical Habitat ◽  
Habitat Features

Fish Habitat: Essential Fish Habitat and Rehabilitation

1999 ◽  
Keyword(s):  
Lake Erie ◽  
Habitat Management ◽  
Fish Habitat ◽  
Learning By Doing ◽  
Suitable Habitat ◽  
Physical Habitat ◽  
Fish Stocks ◽  
Habitat Features ◽  
Fish Habitats

<em>Abstract.—</em> The quality and quantity of habitats determine ecosystem productivity. Hence, they determine the potential fish productivity that sustains the fish harvests extractable from freshwaters and seas. Efforts to conserve and protect fish habitats are frustrated by key unanswered questions: which habitat types and how much must be protected to ensure natural self-sustaining fish stocks? Minns and Bakelaar presented a prototype method for assessing suitable habitat supply for fish stocks in Lake Erie, an analysis that can be used to address conservation issues. Here, the method is refined and extended, taking the assessment of habitat supply for pike <em>Esox lucius </em> in the Long Point region of Lake Erie as a case study. As with the previous study, much emphasis is placed on “learning by doing.” Because available inventories of habitat features are coarse and incomplete, improved guidelines for estimating habitat supply are expected from these prototype studies. The habitat supply method previously presented by Minns and Bakelaar is elaborated in three ways here: (1) the basic physical habitat assessment is derived from a remote-sensing inventory database; (2) methods of quantifying the thermal regime and integrating it with other habitat elements are examined; (3) habitat supply estimates are used in a pike population model, and pike biomass and production are simulated for the Long Point region of Lake Erie and then compared with available records. The roles of error and uncertainty are examined for all elements in the estimation and application of suitable habitat supply values. There is potential for supply measurement and analysis to guide fish habitat management.

Landscape Influences on Stream Habitats and Biological Assemblages

2006 ◽  
Keyword(s):  
Great Plains ◽  
Spatial Scales ◽  
Management Strategies ◽  
Groundwater Potential ◽  
Physical Habitat ◽  
Habitat Features ◽  
Notropis Topeka ◽  
Using Data ◽  
Topeka Shiner ◽  
Valley Segment

<em>Abstract.</em>—The Topeka shiner <em>Notropis topeka </em>is a small cyprinid listed as endangered in 1999 due to an 80% reduction in its former range across six Great Plains states. Conservation and recovery plans require information on structural indices of existing populations, distribution, and habitat relations at several spatial scales. We examined physical habitat associations of Topeka shiners at the valley segment and reach scales, and associations with fish species using stepwise logistic regression. Fish and habitat data were collected at 52 sites. Habitat features at the valley segment scale were acquired using data from a geographic information system. At the valley segment scale, Topeka shiners were associated with stream condition variables (stream size, groundwater potential, channel slope, streamflow, network position) and land-cover variables (% pasture, % trees). At the reach scale, Topeka shiners were associated with low grazing and small trees in riparian zones, low bank height, less submerged vegetation, and coarse substrates. Topeka shiners were associated with five fishes that inhabit small, intermittent, warmwater streams. Evidence of greater abundance of Topeka shiner populations in our region compared to other regions may be a result of the natural character of the streams and associated wetlands, which can influence the habitat variables associated with Topeka shiners at both scales. We identified management strategies that would be effective at conserving habitat of Topeka shiners at large and local scales.

scholarly journals DISTRIBUTION OF SPAWNING AND NURSERY GROUNDS FOR DEEP–WATER RED SHRIMPS IN THE CENTRAL WESTERN MEDITERRANEAN SEA

2014 ◽  
Vol 16 (1) ◽  
pp. 117 ◽  
Author(s):  
F. PALMAS ◽  
P. ADDIS ◽  
S. CABIDDU ◽  
D. CUCCU ◽  
M. C. FOLLESA ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Temporal Distribution ◽  
Relevant Information ◽  
Western Mediterranean ◽  
Physical Habitat ◽  
Nursery Areas ◽  
Nursery Grounds ◽  
Habitat Features ◽  
Western Mediterranean Sea ◽  
Partial Overlap

The presence of spawning and nursery grounds of Aristeids in the central western Mediterranean Sea were investigated using fishery-independent data (trawl surveys, 1994–2012). Spatial distributions were generated for mature animals and recruits, for both spring/summer and autumn data, using an inverse distance weighted deterministic interpolation. The persistence index was used to identify stable spawning and nursery grounds in the Sardinian slope region for Aristaeomorpha foliacea and Aristeus antennatus. Areas of aggregation for recruits and mature females appear connected with important physical habitat features. The analysis also suggests a seasonal bathymetric distribution for nursery areas. The recruits of A. foliacea are located in the upper part of the continental slope (377-450 m) in spring-summer and reach greater depths (468-628 m) in autumn. For A. antennatus, for which nursery areas only emerge in autumn, there is presumably an opposite ontogenic migration, from deep sea to upper slope, during the summer (575-681 m). Results indicate also a partial overlap between the nursery and spawning grounds of both species. In this particular areas, local environmental conditions such as upwelling events or the presence of canyons and seamounts seem to play an important role in their distribution. This study generated also relevant information on the spatial and temporal distribution of seasonal or persistent aggregations of spawners and recruits, providing scientific elements to suggest the feasibility of protecting these important resources.

scholarly journals Geomorphic identification of physical habitat features in a large, altered river system

2018 ◽  
Vol 40 ◽  
pp. 02031
Author(s):  
Lucie Guertault ◽  
Garey Fox ◽  
Shannon Brewer
Keyword(s):  
River System ◽  
Aerial Imagery ◽  
Physical Habitat ◽  
Habitat Assessment ◽  
Ecological Processes ◽  
Field Surveys ◽  
High Resolution Data ◽  
Stream Classification ◽  
Habitat Features ◽  
Primary Identification

Altered flow regimes in streams can significantly affect ecosystems and disturb ecological processes, leading to species loss and extinction. Many river management projects use stream classification and habitat assessment approaches to design practical solutions to reverse or mitigate adverse effects of flow regime alteration on stream systems. The objective of this study was to develop a methodology to provide a primary identification of physical habitats in an 80-km long segment of the Canadian River in central Oklahoma. The methodology relied on basic geomorphic variables describing the stream and its floodplain that were derived from aerial imagery and Lidar data using Geographic Information Systems. Geostatistical tests were implemented to delineate habitat units. This approach based on high resolution data and did not require in-site inspection provided a relatively refined habitat delineation, consistent with visual observations. Future efforts will focus on validation via field surveys and coupling with hydro-sedimentary modeling to provide a tool for environmental flow decisions.

Habitat associations of a rare South Australian sea star (Parvulastra parvivipara) and a co-occurring chiton (Ischnochiton variegatus): implications for conservation

2015 ◽  
Vol 21 (3) ◽  
pp. 234 ◽  
Author(s):  
Kiran Liversage
Keyword(s):  
Community Dynamics ◽  
Physical Stability ◽  
South Australia ◽  
Habitat Associations ◽  
Small Range ◽  
Physical Habitat ◽  
Sea Star ◽  
Sea Levels ◽  
Habitat Features ◽  
Rising Sea Levels

The sea star Parvulastra parvivipara is a small-range endemic known from only seven granitic headlands in South Australia. Evidence from previous studies suggests that its unstable boulder habitat will experience increased disturbance as sea levels rise. This study investigated distributional and ontogenetic patterns of P. parvivipara across different-sized boulders that vary in physical stability and susceptibility to disturbance. To develop a better understanding of community dynamics in P. parvivipara habitat, patterns were also assessed for a chiton with which the sea star commonly co-occurs (Ischnochiton variegatus), and assemblages of encrusting species were also measured, as these can vary amongst boulder sizes and influence mobile animals. Large boulders had many tubeworms, contributing to a significant boulder-size effect on encrusting species assemblage structure. P. parvivipara was most abundant on the smallest boulders; there was no evidence that abundances were influenced by encrusters. I. variegatus abundances were unaffected by boulder size, but a positive correlation between lengths of individuals and encruster cover occurred on the smallest boulders. Overall, physical habitat features, not encrusting biota, likely caused an association of P. parvivipara with small boulders, while I. variegatus displayed apparent ontogenetic use of encruster-related habitat features. As P. parvivipara uses mostly small boulders that are particularly susceptible to disturbances that are increasing with rising sea levels, future ecological restoration efforts to protect this rare species may be required. Such efforts can be properly informed about necessary habitat requirements from these results.

Movements, habitat use, and entrainment of stocked juvenile lake sturgeon in a hydroelectric reservoir system

2020 ◽  
Vol 77 (3) ◽  
pp. 611-624
Author(s):  
Jonathan Hegna ◽  
Kim Scribner ◽  
Edward Baker
Keyword(s):  
Habitat Use ◽  
Fish Passage ◽  
Lake Sturgeon ◽  
Suitable Habitat ◽  
Physical Habitat ◽  
Habitat Conditions ◽  
Key Factors ◽  
Habitat Features ◽  
Use Patterns ◽  
Northern Michigan

Identifying movement and habitat use patterns is essential for fish passage efforts and the conservation of threatened species. We used acoustic telemetry to track the movements of 44 juvenile lake sturgeon (Acipenser fulvescens) throughout Kleber Reservoir in northern Michigan. On average, lake sturgeon moved 502 m between telemetry positions, with age-2 lake sturgeon moving longer distances than age-1 lake sturgeon. Areas with high numbers of lake sturgeon detections were clustered near the forebay, while zones with low numbers of detections were clustered toward the head of the reservoir. Analyses showed that 66.4% of the variance in habitat use could be explained by physical habitat features. Reservoir areas with ample deepwater habitat, fine soft substrates, and limited macrophyte vegetation were the most frequently occupied and, thus, may provide suitable habitat conditions to support juvenile lake sturgeon. We observed that 54.4% of the age-1 and 52.8% of the age-2 lake sturgeon stocked into Kleber Reservoir were entrained. Reservoir size, morphology, and the location of suitable habitat in relation to hydroelectric infrastructure may be key factors that affect entrainment rates.

scholarly journals Bioenergetic calculations evaluate changes to habitat quality for salmonid fishes in streams treated with salmon carcass analog

2016 ◽  
Vol 73 (5) ◽  
pp. 819-831 ◽  
Author(s):  
Ernest R. Keeley ◽  
Steven O. Campbell ◽  
Andre E. Kohler
Keyword(s):  
Habitat Quality ◽  
Invertebrate Drift ◽  
Physical Habitat ◽  
Net Energy ◽  
Energy Availability ◽  
Salmonid Fishes ◽  
Nutrient Supplementation ◽  
Habitat Features ◽  
Net Energy Intake ◽  
Salmon Carcass

Nutrient supplementation in oligotrophic streams is proposed as a means of mitigating losses of marine-derived subsidies from declining or extirpated populations of anadromous fishes. One of the central predictions of nutrient addition is an increased production of fish through bottom-up increases in invertebrate abundance. Such changes in food availability may increase growth and production rates for stream fishes by increasing habitat quality. In this study we apply bioenergetic calculations to estimate changes to habitat quality based on predicted increases in net energy intake. We compared invertebrate drift abundance and estimated changes in energy availability in streams treated with salmon carcass analog versus untreated controls. Our results revealed a two- to threefold increase in invertebrate drift abundance following the addition of salmon carcass analog; however, this effect appeared to be short-term. Measures of the energetic profitability of stream habitat for salmonid fishes revealed small, yet significant, increases in net energy availability in streams that received analog additions, but only after controlling for differences in physical habitat features such as temperature and stream flow.

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