Year-class detection reveals climatic modulation of settlement strength in the European lobster, Homarus gammarus

Understanding the nature of recruitment relationships in the European lobster, Homarus gammarus, has been an intractable problem because of difficulties associated with quantification of its scarce planktonic larvae and early benthic phase. We attempt to address this problem by analyzing the age composition of a population off the northeast coast of England. Age-dependent in situ deposits of neurolipofuscin in the eyestalk are used as an age index. An approach is presented that accounts and (or) corrects for the two most important potential sources of error in age determinations by this technique, namely environmental temperature variation and unexplained individual variation. This yields, for the first time in very long-lived clawed lobsters, reproducible catch age structures with year-class resolution. The method should be generally applicable to crustaceans. Cross-correlation analysis shows that larval settlement strength in the European lobster is associated with local sea temperatures and onshore winds in a manner similar to that reported for other lobsters. These findings have important implications for stock assessment, particularly the use of traditional models dependent on size and steady state, yield forecasting, the effects of global climate change, arguments about spawner protection or restocking, and the spawnerrecruit relationship.

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The effect of cover on in situ predation in early benthic phase European lobster Homarus gammarus

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315401004301 ◽

2001 ◽

Vol 81 (4) ◽

pp. 639-642 ◽

Cited By ~ 16

Author(s):

Brendan Ball ◽

Adrian Linnane ◽

Brian Munday ◽

Ronan Browne ◽

John P. Mercer

Keyword(s):

Benthic Fish ◽

European Lobster ◽

Homarus Gammarus ◽

Pomatoschistus Minutus ◽

Predatory Attack

This study examined the role of predation in restricting early benthic phase (EBP) lobsters to shelter-providing substrata. In the field, the survival of animals provided with cover in the form of cobble and gravel substrata was significantly higher than unsheltered controls. Small benthic fish, particularly gobies Pomatoschistus minutus and rockling Ciliata mustela were the primary predators subtidally while crabs Carcinus maenus appeared to be the dominant intertidal predator. Predatory attack primarily occurred within minutes of the lobsters being deployed. The study reinforces the role played by predation in restricting EBP European lobsters to shelter-providing substrata.

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Recorded captures of American lobster (Homarus americanus) in Swedish waters and an observation of predation on the European lobster (Homarus gammarus)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2016-0532 ◽

2017 ◽

Vol 74 (10) ◽

pp. 1503-1506 ◽

Cited By ~ 2

Author(s):

Vidar Øresland ◽

Mats Ulmestrand ◽

Ann-Lisbeth Agnalt ◽

Gert Oxby

Keyword(s):

Native Species ◽

Homarus Americanus ◽

American Lobster ◽

Swedish West Coast ◽

Marine Research ◽

European Lobster ◽

Homarus Gammarus ◽

Genetic Sampling ◽

Identification Measurements ◽

First Time

The intentional or unintentional release of American lobsters (Homarus americanus), imported through the European seafood trade, has resulted in findings of H. americanus in European waters. A total of 36 specimens was recorded within a smaller area, halfway along the Swedish west coast, between 2008 and 2016. The lobsters were caught by both recreational and professional fishermen and delivered to the Institute of Marine Research in Lysekil, where species identification, measurements, and genetic sampling were performed. Twenty-five of these lobsters were caught inside the sill of the Gullmar Fjord, most of them close to Lysekil harbor, where escapes from an illegal holding is suspected. Six females had eggs, which in two cases were hybrids. While there is no evidence to suggest that a population has been established in the Gullmar Fjord or elsewhere in Swedish waters, serious concerns must be raised regarding the possible consequences for the native species. An American lobster has for the first time been filmed eating a killed European lobster (Homarus gammarus) in Swedish waters.

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The polychaete Histriobdella homari and major groups of epibionts on the European lobster, Homarus gammarus and other decapods

Crustaceana ◽

10.1163/15685403-00003865 ◽

2019 ◽

Vol 92 (2) ◽

pp. 189-203

Author(s):

Vidar Øresland

Keyword(s):

Carapace Length ◽

Homarus Americanus ◽

Parasitic Copepod ◽

Analytic Method ◽

Quantitative Biology ◽

European Lobster ◽

Homarus Gammarus ◽

First Time

Abstract The quantitative biology and ecology of epibiotic communities on decapods are only vaguely known. An analytic method revealed close to 100% of metazoan epibionts among the eggs and gills of some decapods in Swedish waters. High abundances of the epibiotic polychaete Histriobdella homari were found (100% prevalence) and European lobsters, Homarus gammarus, with a carapace length of 100 mm have, as a mean, approx. 6700 H. homari among their old eggs, underlining the importance of these epibiont polychaetes as cleaners of lobster eggs (and gills). For the first time, a nematode (Pontonema sp.) was found feeding on H. homari. Gills of American lobsters, Homarus americanus, caught in Swedish waters were infested with the European parasitic copepod Nicothoe astaci (80% prevalence). This study shows that on decapods a number of epibionts (Ciliophora, Nematoda, Hydrachnidia, Copepoda, Ostracoda, Amphipoda and Kinorhyncha) can be quantified, using the method adopted here, which will enable a better understanding of epibiotic communities.

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Single Nucleotide Polymorphisms Are Suitable For Assessing The Success of Restocking Efforts of The European Lobster (Homarus Gammarus, L.)

10.21203/rs.3.rs-292738/v1 ◽

2021 ◽

Author(s):

Pierre De Wit ◽

Linda Svanberg ◽

Isabel Casties ◽

Susanne P Eriksson ◽

Kristina Sundell ◽

...

Keyword(s):

Dna Marker ◽

Nucleotide Polymorphisms ◽

Population Assignment ◽

Single Nucleotide ◽

Swedish West Coast ◽

European Lobster ◽

Homarus Gammarus ◽

Snp Panel ◽

First Time ◽

A Current

Abstract The European lobster (Homarus gammarus) forms the base of an important fishery along the coasts of Europe. However, stocks have been in decline for many years, prompting new regulations in the fishery and also restocking efforts. An important feature of any restocking effort is the assessment of success in the number of released juveniles that stay and become adult over time. Here, we tested the power of a SNP DNA marker panel developed for population assignment to correctly infer parentage on the maternal side of lobster larvae, in the absence of known fathers, using lobsters included in a current restocking effort on the Swedish west coast. We also examined the power to reconstruct the unknown paternal genotypes, and examined the number of fathers for each larval clutch. We found that the 96-SNP panel, despite only containing 78 informative markers, allowed us to assign all larvae to the correct mother. Furthermore, with 10 genotyped larvae or more, confident paternal genotypes could be reconstructed. We also found that 15 out of 17 clutches were full siblings, whereas two clutches had two fathers. To our knowledge, this is the first time a SNP panel of this size has been used to assess parentage in a crustacean restocking effort. Our conclusion is that the panel works well, and that it could be an important tool for the assessment of restocking success of H. gammarus in the future.

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Population Characteristics of the European Lobster, Homarus gammarus in the Adriatic Sea: Implications for Sustainable Fisheries Management

Water ◽

10.3390/w13081072 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1072

Author(s):

Mišo Pavičić ◽

Sanja Matić-Skoko ◽

Dario Vrdoljak ◽

Ante Vujević

Keyword(s):

Adriatic Sea ◽

Stock Assessment ◽

Legal Framework ◽

Population Characteristics ◽

Sex Characteristics ◽

Effective Management ◽

Northern Adriatic ◽

European Lobster ◽

Homarus Gammarus ◽

Secondary Sex Characteristics

The European lobster, Homarus gammarus, was sampled from September 2016 to August 2017, using pots and gillnets in the Eastern Adriatic Sea. Official landings were also analyzed (2008–2020). The majority of landings were from the Northern Adriatic and showed an increase of 18.5% over the study period. Results revealed an extremely low catch rate that fluctuated significantly by season. Dominance by specimens in the size classes of 90–110 mm carapace length (CL) was observed. Experimental design revealed spatial heterogeneity, with larger individuals caught further from the coast (>3 nm) and undersized specimens caught near the coast (<3 nm). With increasing CL and total length (TL), an increase in weight was higher in males than females. TL and abdomen width (AW) increased linearly with CL and were more pronounced in females. At 80 mm CL, females started to develop secondary sex characteristics with wider AW than males. The results suggest that the modern legal framework is appropriate for lobster fisheries and a longer fishing season is not advisable, despite a positive catch trend in the northern part of the sea. Additional efforts are desirable to reduce fishing pressure in the coastal part. The morphometric relationships could reveal population characteristics required as inputs in stock assessment analysis for effective management.

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Single nucleotide polymorphisms are suitable for assessing the success of restocking efforts of the European lobster (Homarus gammarus, L.)

Conservation Genetics Resources ◽

10.1007/s12686-021-01234-3 ◽

2021 ◽

Author(s):

Pierre De Wit ◽

Linda Svanberg ◽

Isabel Casties ◽

Susanne P. Eriksson ◽

Kristina Sundell ◽

...

Keyword(s):

Dna Marker ◽

Nucleotide Polymorphisms ◽

Nucleotide Polymorphism ◽

Single Nucleotide ◽

Swedish West Coast ◽

European Lobster ◽

Homarus Gammarus ◽

Snp Panel ◽

First Time ◽

A Current

AbstractThe European lobster (Homarus gammarus) forms the base of an important fishery along the coasts of Europe. However, stocks have been in decline for many years, prompting new regulations in the fishery and also restocking efforts. An important feature of any restocking effort is the assessment of success in the number of released juveniles that stay and become adult over time. Here, we tested the power of a single nucleotide polymorphism (SNP) DNA marker panel developed for population assignment to correctly infer parentage on the maternal side of lobster larvae, in the absence of known fathers, using lobsters included in a current restocking effort on the Swedish west coast. We also examined the power to reconstruct the unknown paternal genotypes, and examined the number of fathers for each larval clutch. We found that the 96-SNP panel, despite only containing 78 informative markers, allowed us to assign all larvae to the correct mother. Furthermore, with ten genotyped larvae or more, confident paternal genotypes could be reconstructed. We also found that 15 out of 17 clutches were full siblings, whereas two clutches had two fathers. To our knowledge, this is the first time a SNP panel of this size has been used to assess parentage in a crustacean restocking effort. Our conclusion is that the panel works well, and that it could be an important tool for the assessment of restocking success of H. gammarus in the future.

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Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

10.26434/chemrxiv.7098695 ◽

2018 ◽

Author(s):

Elaine A. Kelly ◽

Judith E. Houston ◽

Rachel Evans

Keyword(s):

Real Time ◽

Absorption Spectroscopy ◽

Self Assembly ◽

Uv Light ◽

Wormlike Micelles ◽

Tetraethylene Glycol ◽

Light Illumination ◽

First Time ◽

Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such asdrug delivery and micellar catalysis. Currently, their behaviour in the equilibrium cis-and trans-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C8AzoOC8E4) using small-angle neutron scattering (SANS). We show that the incorporation of in-situUV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C8AzoOC8E4could switch between wormlike micelles (transnative state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked in-situthrough combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

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The Total Synthesis of Rhabdastrellic Acid A

10.26434/chemrxiv.7479944 ◽

2018 ◽

Author(s):

Yaroslav Boyko ◽

Christopher Huck ◽

David Sarlah

Keyword(s):

Total Synthesis ◽

Late Stage ◽

Cross Coupling ◽

Side Chains ◽

General Strategy ◽

Modular Approach ◽

Linear Sequence ◽

Generating Sequence ◽

First Time

<div>The first total synthesis of rhabdastrellic acid A, a highly cytotoxic isomalabaricane triterpenoid, has been accomplished in a linear sequence of 14 steps from commercial geranylacetone. The prominently strained trans-syn-trans-perhydrobenz[e]indene core characteristic of the isomalabaricanes is efficiently accessed in a selective manner for the first time through a rapid, complexity-generating sequence incorporating a reductive radical polyene cyclization, an unprecedented oxidative Rautenstrauch cycloisomerization, and umpolung 𝛼-substitution of a p-toluenesulfonylhydrazone with in situ reductive transposition. A late-stage cross-coupling in concert with a modular approach to polyunsaturated side chains renders this a general strategy for the synthesis of numerous family members of these synthetically challenging and hitherto inaccessible marine triterpenoids.</div>

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Engineered Phage Endolysin Eliminates Gardnerella Biofilm without Damaging Beneficial Bacteria in Bacterial Vaginosis Ex Vivo

Pathogens ◽

10.3390/pathogens10010054 ◽

2021 ◽

Vol 10 (1) ◽

pp. 54

Author(s):

Christine Landlinger ◽

Lenka Tisakova ◽

Vera Oberbauer ◽

Timo Schwebs ◽

Abbas Muhammad ◽

...

Keyword(s):

Bacterial Vaginosis ◽

Bactericidal Activity ◽

High Selectivity ◽

Ex Vivo ◽

Vaginal Microbiome ◽

Wild Type ◽

Wild Type Enzyme ◽

Promising Alternative ◽

First Time

Bacterial vaginosis is characterized by an imbalance of the vaginal microbiome and a characteristic biofilm formed on the vaginal epithelium, which is initiated and dominated by Gardnerella bacteria, and is frequently refractory to antibiotic treatment. We investigated endolysins of the type 1,4-beta-N-acetylmuramidase encoded on Gardnerella prophages as an alternative treatment. When recombinantly expressed, these proteins demonstrated strong bactericidal activity against four different Gardnerella species. By domain shuffling, we generated several engineered endolysins with 10-fold higher bactericidal activity than any wild-type enzyme. When tested against a panel of 20 Gardnerella strains, the most active endolysin, called PM-477, showed minimum inhibitory concentrations of 0.13–8 µg/mL. PM-477 had no effect on beneficial lactobacilli or other species of vaginal bacteria. Furthermore, the efficacy of PM-477 was tested by fluorescence in situ hybridization on vaginal samples of fifteen patients with either first time or recurring bacterial vaginosis. In thirteen cases, PM-477 killed the Gardnerella bacteria and physically dissolved the biofilms without affecting the remaining vaginal microbiome. The high selectivity and effectiveness in eliminating Gardnerella, both in cultures of isolated strains as well as in clinically derived samples of natural polymicrobial biofilms, makes PM-477 a promising alternative to antibiotics for the treatment of bacterial vaginosis, especially in patients with frequent recurrence.

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Chromosomal painting of the sandpiper (Actitis macularius) detects several fissions for the Scolopacidae family (Charadriiformes)

BMC Ecology and Evolution ◽

10.1186/s12862-020-01737-x ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Melquizedec Luiz Silva Pinheiro ◽

Cleusa Yoshiko Nagamachi ◽

Talita Fernanda Augusto Ribas ◽

Cristovam Guerreiro Diniz ◽

Patricia Caroline Mary O´Brien ◽

...

Keyword(s):

Chromosome Painting ◽

Diploid Number ◽

Chromosomal Evolution ◽

Long Distance ◽

Chromosomal Painting ◽

Cytogenetic Studies ◽

Burhinus Oedicnemus ◽

Clear Idea ◽

First Time

Abstract Background The Scolopacidae family (Suborder Scolopaci, Charadriiformes) is composed of sandpipers and snipes; these birds are long-distance migrants that show great diversity in their behavior and habitat use. Cytogenetic studies in the Scolopacidae family show the highest diploid numbers for order Charadriiformes. This work analyzes for the first time the karyotype of Actitis macularius by classic cytogenetics and chromosome painting. Results The species has a diploid number of 92, composed mostly of telocentric pairs. This high 2n is greater than the proposed 80 for the avian ancestral putative karyotype (a common feature among Scolopaci), suggesting that fission rearrangements have formed smaller macrochromosomes and microchromosomes. Fluorescence in situ hybridization using Burhinus oedicnemus whole chromosome probes confirmed the fissions in pairs 1, 2, 3, 4 and 6 of macrochromosomes. Conclusion Comparative analysis with other species of Charadriiformes studied by chromosome painting together with the molecular phylogenies for the order allowed us to raise hypotheses about the chromosomal evolution in suborder Scolopaci. From this, we can establish a clear idea of how chromosomal evolution occurred in this suborder.

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