scholarly journals Prehistoric baseline reveals substantial decline of oyster reef condition in a Gulf of Mexico conservation priority area

2020 ◽  
Vol 16 (2) ◽  
pp. 20190865 ◽  
Author(s):  
Stephen G. Hesterberg ◽  
Gregory S. Herbert ◽  
Thomas J. Pluckhahn ◽  
Ryan M. Harke ◽  
Nasser M. Al-Qattan ◽  
...  
Keyword(s):  
Life History ◽  
Stable Isotope ◽  
Gulf Of Mexico ◽  
Oyster Reef ◽  
Management Strategies ◽  
Conservation Priority ◽  
Habitat Condition ◽  
Substantial Decline ◽  
Reef Condition ◽  
Population Resilience

The Gulf of Mexico (GoM) is home to the world's largest remaining wild oyster fisheries, but baseline surveys needed to assess habitat condition are recent and may represent an already-shifted reference state. Here, we use prehistoric oysters from archaeological middens to show that oyster size, an indicator of habitat function and population resilience, declined prior to the earliest assessments of reef condition in an area of the GoM previously considered pristine. Stable isotope sclerochronlogy reveals extirpation of colossal oysters occurred through truncated life history and slowed growth. More broadly, our study suggests that management strategies affected by shifting baselines may overestimate resilience and perpetuate practices that risk irreversible decline.

scholarly journals Contributions to Management Strategies in the NE Atlantic Regarding the Life History and Population Structure of a Key Deep-Sea Fish (Mora moro)

Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 522
Author(s):  
Régis Santos ◽  
Wendell Medeiros-Leal ◽  
Osman Crespo ◽  
Ana Novoa-Pabon ◽  
Mário Pinho
Keyword(s):  
Population Structure ◽  
Life History ◽  
Deep Sea ◽  
Management Strategies ◽  
Size Composition ◽  
Large Size ◽  
The Common ◽  
Fishing Impacts ◽  
Sea Fish

With the commercial fishery expansion to deeper waters, some vulnerable deep-sea species have been increasingly captured. To reduce the fishing impacts on these species, exploitation and management must be based on detailed and precise information about their biology. The common mora Mora moro has become the main deep-sea species caught by longliners in the Northeast Atlantic at depths between 600 and 1200 m. In the Azores, landings have more than doubled from the early 2000s to recent years. Despite its growing importance, its life history and population structure are poorly understood, and the current stock status has not been assessed. To better determine its distribution, biology, and long-term changes in abundance and size composition, this study analyzed a fishery-dependent and survey time series from the Azores. M. moro was found on mud and rock bottoms at depths below 300 m. A larger–deeper trend was observed, and females were larger and more abundant than males. The reproductive season took place from August to February. Abundance indices and mean sizes in the catch were marked by changes in fishing fleet operational behavior. M. moro is considered vulnerable to overfishing because it exhibits a long life span, a large size, slow growth, and a low natural mortality.

The Hidden Half: Linking microbial communities to habitat condition and vegetation management in UK blanket bogs

2021 ◽  
Author(s):  
William Burn ◽  
Andreas Heinemeyer ◽  
Thorunn Helgason ◽  
David Glaves ◽  
Michael Morecroft
Keyword(s):  
Water Quality ◽  
Ecosystem Services ◽  
Microbial Communities ◽  
Structural Equation ◽  
Management Strategies ◽  
Vegetation Management ◽  
Equation Model ◽  
Habitat Condition ◽  
Blanket Bog ◽  
The Uk

<p>Peatlands are globally valued for the ecosystem services they deliver, including water quality regulation and carbon sequestration. In the UK, blanket bogs are the main peatland habitat and previous work has linked blanket bog management, especially rotational burning of heather vegetation on grousemoors, to impacts on these ecosystem services. However, we still lack a mechanistic, process-level understanding of how peatland management and habitat status is linked to ecosystem service provision, which is mostly driven by soil microbial processes.</p><p>Here we examine bacterial and fungal communities across a spectrum of “intact” to degraded UK blanket bogs and under different vegetation management strategies. Sites included grousemoors under burnt and alternative mown or uncut management along with further locations including 'near intact', degraded and restored sites across a UK climatic gradient ranging from Exmoor (South UK), the Peak District (Mid) to the Flow Country (North). Moreover, an experiment was setup at the University of York with peat mesocosms taken from all sites and management/habitat conditions to allow a comparison between field and controlled conditions and assessing root-mediated processes. Using a structural equation model, we linked grousemoor management to specific fungal/bacterial functional groups, and have started to relate this to changes in water quality provision and carbon cycle aspects. This represents a significant step in the effort to use microbial communities as indicators of peatland habitat condition in UK upland blanket bogs. </p><p> </p>

Dietary composition of endangered seahorses determined by stable isotope analysis

2017 ◽  
Vol 68 (5) ◽  
pp. 831 ◽  
Author(s):  
S. Valladares ◽  
D. X. Soto ◽  
M. Planas
Keyword(s):  
Stable Isotope ◽  
Environmental Changes ◽  
Conservation Status ◽  
Management Strategies ◽  
Isotope Analysis ◽  
Primary Source ◽  
Habitat Characteristics ◽  
Conservation Actions ◽  
Isotope Mixing Models ◽  
North Western

The lack of integrated measures for assessing the feeding ecology of seahorses may restrict the effectiveness of conservation actions on wild populations of worldwide threatened seahorse species. Identifying dietary sources will allow researchers to determine their degree of vulnerability to environmental changes, redefine their conservation status and apply appropriate management strategies. The resource use of the seahorse Hippocampus guttulatus inhabiting coastal waters of Galicia (north-western Iberian Peninsula) was assessed for three populations and 2 years using stable isotope mixing models. The Bayesian mixing model (MixSIAR) estimated the relative contributions of the dietary sources to the seahorse diet and revealed that Caprellidea were the primary source, followed by Gammaridea and Caridea. Mysidae and Annelida represented the less dominant prey. This prey preference can be explained by the foraging behaviour of seahorses. Different contributions of Gammaridea and Caridea to the diet were found among sites, indicating different habitat characteristics and hence different habitat use by seahorses within each site. In addition, differences were encountered among sexes. Caprellidea was the dominant prey for females, whereas Gammaridea was the dominant prey for males. The findings of the present study will contribute to the knowledge of feeding patterns of H. guttulatus, providing relevant data for conservation of this endangered species.

Oyster reef restoration in the northern Gulf of Mexico: Extent, methods and outcomes

2014 ◽  
Vol 89 ◽  
pp. 20-28 ◽  
Author(s):  
Megan La Peyre ◽  
Jessica Furlong ◽  
Laura A. Brown ◽  
Bryan P. Piazza ◽  
Ken Brown
Keyword(s):  
Gulf Of Mexico ◽  
Oyster Reef ◽  
Reef Restoration ◽  
Northern Gulf Of Mexico

Biology, Management, and Protection of North American Sturgeon

2002 ◽  
Keyword(s):  
Life History ◽  
Gulf Of Mexico ◽  
River System ◽  
Ultrasonic Telemetry ◽  
Marine Habitat ◽  
Gulf Sturgeon ◽  
Sandy Substrate ◽  
Sampling Locations ◽  
Acipenser Oxyrinchus Desotoi ◽  
Acipenser Oxyrinchus

Abstract.<em>—</em>Although most species of anadromous sturgeons worldwide are threatened with extinction, information on the estuarine and marine components of their life history is generally lacking. During March 1997 to July 1999, we used ultrasonic telemetry to examine estuarine and marine habitat use of adult Gulf sturgeon <em>Acipenser oxyrinchus desotoi</em> from the Choctawhatchee Bay/River System, Florida. During winter and spring, telemetered Gulf sturgeon were distributed nonrandomly within Choctawhatchee Bay, with most relocations in nearshore areas 2–4 m deep. Within the bay, Gulf sturgeon occasionally moved long distances but usually remained in localized areas (<1 km<sup>2</sup>) for several weeks. Areas where Gulf sturgeon remained for prolonged periods were characterized by sandy substrate harboring a benthic community dominated by crustaceans and annelids. A majority of male Gulf sturgeon remained exclusively in Choctawhatchee Bay during the winter and spring. In contrast, a majority of females during this time were either relocated in the Gulf of Mexico or were absent at sampling locations, having last been detected at bay entrances. Declines in habitat quality in Choctawhatchee Bay and the Gulf of Mexico may hinder recovery of this species, since adult Gulf sturgeon rely on these areas for nourishment during periods of gonadal growth.

Kokanee–sockeye salmon hybridization leads to intermediate morphology and resident life history: implications for fisheries management

2020 ◽  
Vol 77 (2) ◽  
pp. 355-364
Author(s):  
Lucas D. Elliott ◽  
Hillary G.M. Ward ◽  
Michael A. Russello
Keyword(s):  
Life History ◽  
Sockeye Salmon ◽  
Management Strategies ◽  
Empirical Support ◽  
Intermediate Morphology ◽  
Intermediate Size ◽  
Freshwater Resident ◽  
Historical Range ◽  
Hybridization And Introgression

Stocking programs designed to return extirpated species to their historical range have become increasingly prevalent, punctuating the need to better understand the risks posed to recipient ecosystems. Here, we investigated the genetic and biological consequences of an anadromous sockeye salmon (Oncorhynchus nerka) stocking program in Skaha Lake, British Columbia, where substantial levels of hybridization and introgression with the native freshwater resident ecotype (kokanee) have been detected. We genetically assigned 543 individuals (adult spawners, age-0 juveniles) to estimate stock proportions (pure-stock sockeye, pure-stock kokanee, or hybrid) between 2010 and 2017, with a subset undergoing otolith microchemistry analysis to determine migratory life history and maternal ancestry. The proportion of hybrid spawners varied from 5% to 20% across sampling years, while that of hybrid age-0 juveniles remained relatively constant (∼11%). Hybrid spawners exhibited intermediate size relative to pure stocks, with the vast majority being nonanadromous (92%) and of resident maternal ancestry (76%). Our results provide empirical support for previously hypothesized mechanisms of hybridization between O. nerka life-history forms and underscore the importance of continued monitoring of stocking programs to quantify long-term fitness impacts of introgression and refine management strategies.

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