scholarly journals Role of mangrove habitat as a nursery for juvenile spiny lobster, Panulirus argus, in Belize

1997 ◽  
Vol 48 (8) ◽  
pp. 721 ◽  
Author(s):  
Charles A. Acosta ◽  
Mark J. Butler IV
Keyword(s):  
Residence Time ◽  
Deep Water ◽  
Spiny Lobster ◽  
Seagrass Beds ◽  
Mangrove Habitat ◽  
Stony Corals ◽  
Spiny Lobsters ◽  
Population Sizes ◽  
A Site

The use of mangrove prop roots and associated coralline habitats by Caribbean spiny lobsters was investigated near two types of mangrove islands in Belize. Spiny lobsters sheltered among mangrove prop roots, in undercut peat banks and under corals near islands, and they ranged in size from newly recruited juveniles to subadults. Lobsters preferred to shelter under large stony corals, but their use of mangrove prop roots nd undercut peat banks increased when the density of corals was low. Den residence time and distance moved within a site were similar at islands isolated by deep water channels and islands separated by shallow seagrass beds, but as a consequence of high immigration rates, population sizes were highest near shallow islands. Predation on newly settled juveniles was greater in seagrass and coral crevices than in mangrove prop roots, whereas the survival of larger juveniles was higher in mangroves and coral patch reefs than in seagrass. These results suggest that mangrove habitats may function as a nursery for juvenile spiny lobsters but that the use of this habitat depends on shelter characteristics and the isolation of islands.

scholarly journals Spiny lobster fisheries status across time and a mosaic of spatial management regimes

2020 ◽  
Vol 77 (3) ◽  
pp. 1002-1016
Author(s):  
Alexander Tewfik ◽  
Elizabeth A Babcock ◽  
Myles Phillips
Keyword(s):  
Spiny Lobster ◽  
Maximum Size ◽  
Fishing Mortality ◽  
Population Status ◽  
Empirical Estimate ◽  
Positive Effects ◽  
Commercial Harvest ◽  
Spatial Management ◽  
Spiny Lobsters

Abstract In Belize, the commercial harvest of spiny lobsters has occurred for ∼100 years, provides critical livelihoods, and is the primary seafood export. We determined the first empirical estimate of size at maturity in Belize as well as eight fishery status indicators on several fishing grounds. The carapace lengths (CLs) at 50% maturity varied between males (98 mm) and females (86 mm) and are higher than the existing legal minimum of 76 mm. Time series analysis indicated decreasing proportions of mature individuals, decreasing size, and low spawning potential ratios (SPR) as well as high fishing mortality within fishing grounds. The pattern of decline in population status indicators across fishing grounds is consistent with a historical expansion of effort from north to south and offshore. Many indicators of population status within fishing grounds were improved with increasing area of replenishment zone and opposite to the historical expansion. However, overfishing is a problem across all areas examined. An increase in the legal minimum CL to 86 mm and examination of a maximum size limit will likely have significant positive effects on productivity and SPR, respectively, as well as protecting the pivotal role of spiny lobsters within the ecosystem.

Salt and Water Balance of the Spiny Lobster Panulirus Argus: The Role of the Gut

1977 ◽  
Vol 70 (1) ◽  
pp. 231-245
Author(s):  
D. F. MALLEY
Keyword(s):  
Sea Water ◽  
Spiny Lobster ◽  
The Body ◽  
Digestive Juice ◽  
Urine Production ◽  
Minor Portion ◽  
Salt And Water Balance ◽  
A Minor ◽  
A Site

1. The rate of drinking of sea water averaged 1.5 ± 0.6 ml/kg body weight per 24 h and accounts for only a minor portion of the uptake of water required to balance estimated urine production. 2. Imbibed water and ions, except Ca2+, are absorbed or diffuse across the gut wall into the haemolymph. The gut appears to be a route of net loss of Ca2+, derived from digestive juice and sea water, from the body. 3. The gut does not appear to be a site of regulation of ionic levels in the haemolymph or a major site of water uptake. Note: Freshwater Institute, 501 University Crescent, Winnipeg, Manitoba, Canada R3T 2N6.

Annual juvenile recruitment of spiny lobsters, Panulirus argus (Decapoda, Palinuridae), in a shallow seagrass bed and a deeper hard bottom off western Puerto Rico

Crustaceana ◽  
2018 ◽  
Vol 91 (2) ◽  
pp. 153-167
Author(s):  
Nilda M. Jiménez ◽  
Ernest H. Williams, Jr. ◽  
Aida Rosario
Keyword(s):  
Puerto Rico ◽  
Natural Habitat ◽  
Spiny Lobster ◽  
Panulirus Argus ◽  
Seagrass Beds ◽  
Caribbean Studies ◽  
Seagrass Bed ◽  
Spiny Lobsters ◽  
Habitat Difference ◽  
Early Recruitment

We found 158 juvenile Caribbean spiny lobsters (Panulirus argus) recruiting over a year into 10 artificial shelters in shallow (2-3 m) seagrass beds, but none recruiting into 10 shelters on deeper (approximately 10 m) hard bottom. Spiny lobster juveniles were observed at 10 m or greater depth in submerged fish cages. They may have been strained out by currents rather than naturally recruiting. A large number of these cages inshore could impede natural lobster recruitment. One of the shallow shelters recruited most (85/158) of the juveniles and two shelters recruited most of all (118/158). With no discernable natural habitat difference, we assume that early recruitment into those shelters and the “guide effect” may have been responsible for these preferences. Previous Caribbean studies found the maximum settling periods of juveniles in August to December. Our results were similar with the exception of having more recruits one month later (August to January). Shelters with covers had more juveniles than those without covers; however, this result was largely due to the preponderance of juveniles in one shelter.

The Return of Alsace to France, 1918-1939

2018 ◽  
Author(s):  
Alison Carrol
Keyword(s):  
National Policy ◽  
Third Republic ◽  
French Society ◽  
German Empire ◽  
Cross Border ◽  
The First World War ◽  
German Speaking ◽  
A Site ◽  
First World

In 1918 the end of the First World War triggered the return of Alsace to France after almost fifty years of annexation into the German Empire. Enthusiastic crowds in Paris and Alsace celebrated the homecoming of the so-called lost province, but return proved far less straightforward than anticipated. The region’s German-speaking population demonstrated strong commitment to local cultures and institutions, as well as their own visions of return to France. As a result, the following two decades saw politicians, administrators, industrialists, cultural elites, and others grapple with the question of how to make Alsace French again. The answer did not prove straightforward; differences of opinion emerged both inside and outside the region, and reintegration became a fiercely contested process that remained incomplete when war broke out in 1939. The Return of Alsace to France examines this story. Drawing upon national, regional, and local archives, it follows the difficult process of Alsace’s reintegration into French society, culture, political and economic systems, and legislative and administrative institutions. It connects the microhistory of the region with the macro levels of national policy, international relations, and transnational networks, and with the cross-border flows of ideas, goods, people, and cultural products that shaped daily life in Alsace. Revealing Alsace to be a site of exchange between a range of interest groups with different visions of the region’s future, this book underlines the role of regional populations and cross-border interactions in forging the French Third Republic.

RNA secondary structure dependence in METTL3–METTL14 mRNA methylation is modulated by the N-terminal domain of METTL3

2020 ◽  
Vol 402 (1) ◽  
pp. 89-98
Author(s):  
Nathalie Meiser ◽  
Nicole Mench ◽  
Martin Hengesbach
Keyword(s):  
Secondary Structure ◽  
Rna Binding ◽  
Specific Protein ◽  
Structure Dependence ◽  
Terminal Domain ◽  
Methylation Assay ◽  
A Site ◽  
Methylation Activity

AbstractN6-methyladenosine (m6A) is the most abundant modification in mRNA. The core of the human N6-methyltransferase complex (MTC) is formed by a heterodimer consisting of METTL3 and METTL14, which specifically catalyzes m6A formation within an RRACH sequence context. Using recombinant proteins in a site-specific methylation assay that allows determination of quantitative methylation yields, our results show that this complex methylates its target RNAs not only sequence but also secondary structure dependent. Furthermore, we demonstrate the role of specific protein domains on both RNA binding and substrate turnover, focusing on postulated RNA binding elements. Our results show that one zinc finger motif within the complex is sufficient to bind RNA, however, both zinc fingers are required for methylation activity. We show that the N-terminal domain of METTL3 alters the secondary structure dependence of methylation yields. Our results demonstrate that a cooperative effect of all RNA-binding elements in the METTL3–METTL14 complex is required for efficient catalysis, and that binding of further proteins affecting the NTD of METTL3 may regulate substrate specificity.

scholarly journals The RelA hydrolase domain acts as a molecular switch for (p)ppGpp synthesis

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Anurag Kumar Sinha ◽  
Kristoffer Skovbo Winther
Keyword(s):  
Active Sites ◽  
Molecular Switch ◽  
Cell Physiology ◽  
Synthetase Activity ◽  
Wild Type ◽  
Functional Studies ◽  
Loop Region ◽  
A Site ◽  
Trna Binding

AbstractBacteria synthesize guanosine tetra- and penta phosphate (commonly referred to as (p)ppGpp) in response to environmental stresses. (p)ppGpp reprograms cell physiology and is essential for stress survival, virulence and antibiotic tolerance. Proteins of the RSH superfamily (RelA/SpoT Homologues) are ubiquitously distributed and hydrolyze or synthesize (p)ppGpp. Structural studies have suggested that the shift between hydrolysis and synthesis is governed by conformational antagonism between the two active sites in RSHs. RelA proteins of γ-proteobacteria exclusively synthesize (p)ppGpp and encode an inactive pseudo-hydrolase domain. Escherichia coli RelA synthesizes (p)ppGpp in response to amino acid starvation with cognate uncharged tRNA at the ribosomal A-site, however, mechanistic details to the regulation of the enzymatic activity remain elusive. Here, we show a role of the enzymatically inactive hydrolase domain in modulating the activity of the synthetase domain of RelA. Using mutagenesis screening and functional studies, we identify a loop region (residues 114–130) in the hydrolase domain, which controls the synthetase activity. We show that a synthetase-inactive loop mutant of RelA is not affected for tRNA binding, but binds the ribosome less efficiently than wild type RelA. Our data support the model that the hydrolase domain acts as a molecular switch to regulate the synthetase activity.

scholarly journals A MODEL OF CREATIVE HERITAGE FOR INDUSTRY: DESIGNING NEW RULES WHILE PRESERVING THE PRESENT SYSTEM OF RULES

2021 ◽  
Vol 1 ◽  
pp. 141-150
Author(s):  
Honorine Harlé ◽  
Pascal Le Masson ◽  
Benoit Weil
Keyword(s):  
Case Studies ◽  
Design Process ◽  
Industry 4.0 ◽  
Innovation Management ◽  
Present System ◽  
Innovative Capability ◽  
Current Change ◽  
A Site ◽  
Do So

AbstractIn industry, there is at once a strong need for innovation and a need to preserve the existing system of production. Thus, although the literature insists on the necessity of the current change toward Industry 4.0, how to implement it remains problematic because the preservation of the factory is at stake. Moreover, the question of the evolution of the system depends on its innovative capability, but it is difficult to understand how a new rule can be designed and implemented in a factory. This tension between preservation and innovation is often explained in the literature as a process of creative destruction. Looking at the problem from another perspective, this article models the factory as a site of creative heritage, enabling creation within tradition, i.e., creating new rules while preserving the system of rules. Two case studies are presented to illustrate the model. The paper shows that design in the factory relies on the ability to validate solutions. To do so, the design process can explore and give new meaning to the existing rules. The role of innovation management is to choose the degree of revision of the rules and to make it possible.

Sign in / Sign up

Export Citation Format

Share Document