scholarly journals Coastal Vegetation and Bathymetry Influence Blue Crab Abundance Across Spatial Scales

2022 ◽  
Author(s):  
Selina L. Cheng ◽  
Kinsey N. Tedford ◽  
Rachel S. Smith ◽  
Sean Hardison ◽  
Michael R. Cornish ◽  
...  
Keyword(s):  
Blue Crab ◽  
Salt Marshes ◽  
Spatial Scales ◽  
Gravid Female ◽  
Habitat Associations ◽  
Habitat Characteristics ◽  
Coastal Vegetation ◽  
Blue Crabs ◽  
Catch Per Unit Effort ◽  
Western Atlantic

AbstractBlue crabs (Callinectes sapidus) are highly mobile, ecologically-important mesopredators that support multimillion-dollar fisheries along the western Atlantic Ocean. Understanding how blue crabs respond to coastal landscape change is integral to conservation and management, but such insights have been limited to a narrow range of habitats and spatial scales. We examined how local-scale to landscape-scale habitat characteristics and bathymetric features (channels and oceanic inlets) affect the relative abundance (catch per unit effort, CPUE) of adult blue crabs across a > 33 km2 seagrass landscape in coastal Virginia, USA. We found that crab CPUE was 1.7 × higher in sparse (versus dense) seagrass, 2.4 × higher at sites farther from (versus nearer to) salt marshes, and unaffected by proximity to oyster reefs. The probability that a trapped crab was female was 5.1 × higher in sparse seagrass and 8 × higher near deep channels. The probability of a female crab being gravid was 2.8 × higher near seagrass meadow edges and 3.3 × higher near deep channels. Moreover, the likelihood of a gravid female having mature eggs was 16 × greater in sparse seagrass and 32 × greater near oceanic inlets. Overall, we discovered that adult blue crab CPUE is influenced by seagrass, salt marsh, and bathymetric features on scales from meters to kilometers, and that habitat associations depend on sex and reproductive stage. Hence, accelerating changes to coastal geomorphology and vegetation will likely alter the abundance and distribution of adult blue crabs, challenging marine spatial planning and ecosystem-based fisheries management.

scholarly journals A Comparison of Traditional and Locally Novel Fishing Gear for the Exploitation of the Invasive Atlantic Blue Crab in the Eastern Adriatic Sea

2021 ◽  
Vol 9 (9) ◽  
pp. 1019
Author(s):  
Luka Glamuzina ◽  
Alexis Conides ◽  
Giorgio Mancinelli ◽  
Branko Glamuzina
Keyword(s):  
Blue Crab ◽  
Significant Contribution ◽  
Adriatic Sea ◽  
Gravid Female ◽  
Fishing Gear ◽  
Blue Crabs ◽  
Catch Per Unit Effort ◽  
Management Tools ◽  
The Mediterranean ◽  
Fyke Nets

The Atlantic Blue Crab Callinectes sapidus has been recognized as invasive in the Mediterranean Sea, where it now provides a significant contribution to artisanal fisheries. In this study, we compared the efficiency, selectivity, and productivity of American wire crab traps and traditional fyke nets for the capture of Blue Crabs in a study conducted from June to December 2019 in the Parila Lagoon (River Neretva Estuary, Croatia). A total of 7707 specimens were caught in 15 wire traps, comprising 6959 males and 749 females. The total catch using 50 traditional fyke traps was 1451 crabs, of which 1211 were males and 240 were females. In general, wire crab traps showed a higher capture selectivity and economic performance compared to fyke nets. The catch per unit effort (CPUE) was 102.76 kg for the American wire crab trap and 5.96 kg for the traditional fyke net. The CPUE of gravid female Blue Crabs was lower for the wire traps than the fyke nets. Herein, the utility of crab traps as selective fishing gear for the capture of Blue Crabs, and management tools for control of the reproductive and recruitment phases of the crab, are discussed, with the perspective of future exploitation of the species as a commercially valuable shellfish product in the Mediterranean.

scholarly journals Sources and Expectations for Hierarchical Structure in Bird-habitat Associations

The Condor ◽  
2006 ◽  
Vol 108 (1) ◽  
pp. 5-12 ◽  
Author(s):  
William B. Kristan
Keyword(s):  
Hierarchical Structure ◽  
Environmental Variables ◽  
Spatial Scales ◽  
Ground Level ◽  
Threshold Level ◽  
Habitat Associations ◽  
Habitat Characteristics ◽  
Coarse Grained ◽  
Fine Grained ◽  
Bird Habitat

Abstract Hierarchical structure in bird-habitat associations can arise from hierarchical structure in environmental variables and from the scale-dependent responses of birds to habitat. Hierarchical structure in environmental variables is expected to result from interactions between variables that differ in grain size (spatial resolution) and frequency, and should occur commonly. Birds cannot accurately sample habitat characteristics at all spatial scales simultaneously, and the habitat chosen for a given purpose may differ depending on whether a bird samples from high above the ground (which is best for sampling coarse-grained variables) or from ground level (which is best for sampling fine-grained variables). Additionally, birds may exhibit an absolute response to a habitat variable, if it is unsuitable beyond some threshold level, or a relative response, if all available habitat is suitable but some is preferred. Models that can represent hierarchical structure in habitat, as well as hierarchical, scale-dependent responses by birds, should provide researchers the best chance of understanding avian habitat associations.

Issues Based on Species Life History and Behavior

2021 ◽  
pp. 89-94
Author(s):  
Joseph A. Veech
Keyword(s):  
Life History ◽  
Habitat Use ◽  
Life Histories ◽  
Radio Telemetry ◽  
Spatial Scales ◽  
Habitat Associations ◽  
Habitat Characteristics ◽  
Habitat Analysis ◽  
The Individual ◽  
And Behavior

Species vary tremendously in their life histories and behavior. The particular life history traits and behavior of the focal species must be considered when designing a study to examine habitat associations. For some species, individuals use different areas (of the landscape or territory) for breeding and foraging. As such, the important characteristics for the foraging and breeding habitats may be different. The dramatically different life stages of some organisms (e.g., amphibians and some insects) often correspond to equally dramatic differences in habitat use between juveniles and adults. For some species, habitat use differs among seasons. Species that are highly mobile and have individuals that move around substantially on a daily or weekly basis are particularly challenging for a habitat analysis. For these species, the most efficient and appropriate study design may be one that tracks individuals (through radio-telemetry or GPS) and analyzes the environmental or habitat characteristics at locations where the individual has stopped, rather than trying to survey for the species in pre-established and insufficiently small survey plots. In addition, individual movement and the issues mentioned above may necessitate that environmental variables are measured and analyzed at multiple spatial scales.

Modeling freshwater mussel distribution in relation to biotic and abiotic habitat variables at multiple spatial scales

2014 ◽  
Vol 71 (10) ◽  
pp. 1483-1497 ◽  
Author(s):  
Ericka E. Hegeman ◽  
Scott W. Miller ◽  
Karen E. Mock
Keyword(s):  
Large Scale ◽  
Freshwater Mussels ◽  
Spatial Scales ◽  
Freshwater Mussel ◽  
Habitat Associations ◽  
Habitat Characteristics ◽  
Physical Habitat ◽  
Lotic Ecosystem ◽  
Unit Scale ◽  
Channel Unit

The habitat requirements of many native freshwater mussels remain unclear despite their imperiled status and ecological importance. To explore scale-specific habitat associations in the three genera of mussels found in the western United States (Anodonta, Gonidea, and Margaritifera) we used a multiscale random forest modeling approach to assess functional habitat parameters throughout a 55 km segment of the upper Middle Fork John Day River in northeastern Oregon. We characterized mussel occurrence and density with respect to the hierarchical, hydrogeomorphic structure by sampling reaches of varying valley confinement and channel units nested within individual reaches. Each genus exhibited unique longitudinal trends and channel unit-use patterns. In particular, the large-scale longitudinal trends in Margaritifera occurrence were associated with hydrogeomorphic characteristics at the reach and channel unit scale, with Margaritifera densities peaking in narrow valley segments and in riffles and runs. At the scale of the channel unit, all mussel genera responded to variation in physical habitat characteristics, particularly those that indicated more stable parts of the channel. Our results suggest that spatial patterns in freshwater mussels are associated with the hierarchical structuring of the lotic ecosystem and may provide guidance to restoration efforts.

scholarly journals Nursery habitat use by juvenile blue crabs in created and natural marshes

2020 ◽  
Author(s):  
D.M. Bilkovic ◽  
R.E. Isdell ◽  
D. Stanhope ◽  
K.T. Angstadt ◽  
K.J. Havens ◽  
...  
Keyword(s):  
Blue Crab ◽  
Salt Marshes ◽  
The United States ◽  
Nursery Habitat ◽  
List Type ◽  
Blue Crabs ◽  
Important Species ◽  
Living Shorelines ◽  
Nursery Habitats ◽  
Living Shoreline

ABSTRACTClimate change and coastal development pressures have intensified the need for shoreline protection. Nature-first approaches that use natural habitats, particularly marshes, are being promoted globally as ecologically-beneficial alternatives to grey infrastructure. The ability of these novel shorelines to provide nursery habitat to blue crab, an ecologically and economically important species along the Atlantic and Gulf coasts of the United States, has not been quantified.We quantified the abundance and size distribution of juvenile blue crabs from a chronosequence of living shorelines (created fringing marshes) spanning 2 to 16 years in age (since construction) and compared with paired natural fringing marshes in the southern Chesapeake Bay.Both created and natural fringing marshes are being used by blue crabs as primary nursery habitats. While there were interannual differences in abundance, young blue crabs (≤ 2.5 cm carapace width) were observed in similar densities and sizes at living shoreline and natural marshes. There was no relationship between the age of the living shoreline and blue crab density, indicating that even the youngest living shorelines (2 years) were providing primary nursery habitat. Young blue crabs were more abundant in more isolated marshes and those that were inundated for longer periods of time each tidal cycle, which may be evidence for habitat-limitation.Synthesis and applications: We provide evidence that juvenile blue crabs are comparably using natural and created fringing salt marshes as primary nursery habitat. Although the relative importance of salt marshes as young crab nursery habitat is not fully understood and likely varies by system, the value of marshes within a suite of available structural nursery habitats may increase under a changing climate. The potential for living shorelines to serve as nursery habitat for an economically important species may provide additional incentives to implement these climate adaptation strategies.

scholarly journals Bidecadal Thermal Changes in the Abyssal Ocean

2014 ◽  
Vol 44 (8) ◽  
pp. 2013-2030 ◽  
Author(s):  
Carl Wunsch ◽  
Patrick Heimbach
Keyword(s):  
Long Memory ◽  
Spatial Scales ◽  
Heat Content ◽  
Deep Ocean ◽  
Meteorological Forcing ◽  
Western Atlantic ◽  
State Estimate ◽  
Content Change ◽  
Thermal Changes ◽  
Surface Disturbances

Abstract A dynamically consistent state estimate is used for the period 1992–2011 to describe the changes in oceanic temperatures and heat content, with an emphasis on determining the noise background in the abyssal (below 2000 m) depths. Interpretation requires close attention to the long memory of the deep ocean, implying that meteorological forcing of decades to thousands of years ago should still be producing trendlike changes in abyssal heat content. Much of the deep-ocean volume remained unobserved. At the present time, warming is seen in the deep western Atlantic and Southern Oceans, roughly consistent with those regions of the ocean expected to display the earliest responses to surface disturbances. Parts of the deeper ocean, below 3600 m, show cooling. Most of the variation in the abyssal Pacific Ocean is comparatively featureless, consistent with the slow, diffusive approach to a steady state expected there. In the global average, changes in heat content below 2000 m are roughly 10% of those inferred for the upper ocean over the 20-yr period. A useful global observing strategy for detecting future change has to be designed to account for the different time and spatial scales manifested in the observed changes. If the precision estimates of heat content change are independent of systematic errors, determining oceanic heat uptake values equivalent to 0.1 W m−2 is possibly attainable over future bidecadal periods.

Scale-dependent relationships between benthic habitat characteristics and abundances of blacklip abalone, Haliotis rubra (Leach)

2010 ◽  
Vol 61 (11) ◽  
pp. 1227 ◽  
Author(s):  
Elisabeth M. A. Strain ◽  
Craig R. Johnson
Keyword(s):  
Spatial Scale ◽  
Red Algae ◽  
Positive Relationship ◽  
Spatial Scales ◽  
Habitat Characteristics ◽  
Benthic Habitat ◽  
Sessile Invertebrates ◽  
Haliotis Rubra ◽  
The Relationship ◽  
Biotic Characteristics

Habitat characteristics can influence marine herbivore densities at a range of spatial scales. We examined the relationship between benthic habitat characteristics and adult blacklip abalone (Haliotis rubra) densities across local scales (0.0625–16 m2), at 2 depths, 4 sites and 2 locations, in Tasmania, Australia. Biotic characteristics that were highly correlated with abalone densities included cover of non-calcareous encrusting red algae (NERA), non-geniculate coralline algae (NCA), a matrix of filamentous algae and sediment, sessile invertebrates, and foliose red algae. The precision of relationships varied with spatial scale. At smaller scales (0.0625–0.25 m2), there was a positive relationship between NERA and ERA, and negative relationships between sediment matrix, sessile invertebrates and abalone densities. At the largest scale (16 m2), there was a positive relationship between NERA and abalone densities. Thus, for some biotic characteristics, the relationship between NERA and abalone densities may be scalable. There was very little variability between depths and sites; however, the optimal spatial scale differed between locations. Our results suggest a dynamic interplay between the behavioural responses of H. rubra to microhabitat and/or to abalone maintaining NERA free of algae, sediment, and sessile invertebrates. This approach could be used to describe the relationship between habitat characteristics and species densities at the optimal spatial scales.

scholarly journals Survival and osmoregulation of the purple marsh crab (Sesarma reticulatum) at varying salinity and pH

2017 ◽  
Vol 95 (12) ◽  
pp. 985-989 ◽  
Author(s):  
C.A. Shaughnessy ◽  
E.C. Anderson ◽  
M. Kasparian ◽  
J.M. LaMontagne ◽  
J.S. Bystriansky
Keyword(s):  
South Carolina ◽  
Salt Marshes ◽  
Trophic Cascade ◽  
Western Atlantic ◽  
Fundamental Niche ◽  
Ion Concentrations ◽  
Physiological Tolerance ◽  
Physiological Limits ◽  
Top Predators ◽  
Sesarma Reticulatum

Overfishing of top predators along the western Atlantic coastline has led to a trophic cascade in salt marshes, with increases in herbivorous purple marsh crab (Sesarma reticulatum (Say, 1817)) abundances in North American estuaries leading to overgrazing of cordgrass (Spartina alterniflora Loisel.) and shoreline erosion. To evaluate potential physiological limits on the range of S. reticulatum within an estuary, we evaluated survival and physiological tolerance of S. reticulatum from the Ashepoo–Combhee–Edisto (ACE) River Basin in South Carolina, USA, to combinations of salinity (5‰ and 30‰) and pH (pH 6.6, 7.6, and 8.6) challenges, representative of estuarine extremes. Survival, haemolymph ion concentrations, and gill Na+,K+-ATPase (NKA) and vacuolar-type H+-ATPase (VHA) activity were measured after a 48 h exposure to each experimental condition. Survival was nearly 100% and osmoregulatory control was maintained across estuarine salinity and pH ranges. Sesarma reticulatum appeared to be robust to all potential combinations of salinity and pH stressors examined in this study, and therefore are likely unrestricted in their fundamental niche based on these stressors throughout an estuary.

scholarly journals Fisionomias das Restingas do Delta do Parnaíba, Nordeste, Brasil (Faces of the Salt Marshes of Delta Parnaíba, Norteastern Brasil)

2011 ◽  
Vol 3 (3) ◽  
pp. 218 ◽  
Author(s):  
Francisco Soares Santos-Filho ◽  
Eduardo Bezerra de Almeida Jr. ◽  
Caio J. dos Reis Santos Soares ◽  
Carmen Silvia Zickel
Keyword(s):  
Environmental Protection ◽  
Salt Marshes ◽  
The State ◽  
River Delta ◽  
Coastal Vegetation ◽  
Brazilian Coast ◽  
Frequent Species ◽  
Concise Description

O presente trabalho traz uma caracterização das restingas da Área de Preservação Ambiental do Delta do Parnaíba, litoral do Piauí, Nordeste do Brasil. Foram estudadas e georreferenciadas as formações vegetais das áreas assentadas sobre solos Quaternários. Foram identificados os três tipos de fisionomias também presentes em outras restingas de diferentes regiões do litoral brasileiro, assim como os subtipos mais freqüentes. Além de uma concisa descrição das fisionomias encontradas no local, o trabalho traz uma lista das espécies mais freqüentes que predominam nestas paisagens.Palavras-Chave: Restingas – Fisionomia da vegetação – Área de Preservação Ambiental do Delta do Parnaíba.  Faces of the Salt Marshes of Delta Parnaíba, Norteastern Brasil   ABSTRACT This paper attempts to characterize ";;;;;;;;;;;;;Restinga";;;;;;;;;;;;; (coastal vegetation) located at EPAs (Environmental Protection Areas) in the Parnaiba river delta by the coast of the state of Piauí, in the northeast of Brazil. Vegetation forms in areas over on soils of the Quaternary age were studied and geographically-referenced. The three types of physiognomy were identified, these being the same types found at other ";;;;;;;;;;;;;Restinga";;;;;;;;;;;;; areas on the Brazilian coast, as well as the most frequent subtypes. Along with a concise description of the physiognomy found on the coast of Piauí, this paper also brings a list of the most frequent species that predominate in this landscape.  Keywords: Vegetal Physiognomy – Parnaiba River Delta Environmental Protection Areas.

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