Population Dynamics and Habitat Suitability of the Intertidal Sea Anemones Anthopleura elegantissima and A. xanthogrammica

Abstract Changes in bottom-up forcing are fundamental drivers of fish population dynamics. Recent literature has highlighted the need to incorporate the role of dynamic environmental conditions in stock assessments as a key step towards adaptive fishery management. Combining a bioclimate envelope model and a population dynamic model, we propose a model-based approach that can incorporate ecosystem products into single-species stock assessments. The framework was applied to a commercially important American lobster (Homarus americanus) stock in the Northwest Atlantic. The bioclimate envelope model was used to hindcast temporal variability in a lobster recruitment habitat suitability index (HSI) using bottom temperature and salinity. The climate-driven HSI was used to inform the lobster recruitment dynamics within the size-structured population dynamics model. The performance of the assessment model with an environment-explicit recruitment function is evaluated by comparing relevant assessment outputs such as recruitment, annual fishing mortality, and magnitude of retrospective biases. The environmentally-informed assessment model estimated (i) higher recruitment and lower fishing mortality and (ii) reduced retrospective patterns. This analysis indicates that climate-driven changes in lobster habitat suitability contributed to increased lobster recruitment and present potential improvement to population assessment. Our approach is extendable to other stocks that are impacted by similar environmental variability.

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Aspects of the larval biology of the sea anemones Anthopleura elegantissima and A. artemisia

Invertebrate Biology ◽

10.1111/j.1744-7410.2002.tb00059.x ◽

2005 ◽

Vol 121 (3) ◽

pp. 190-201 ◽

Cited By ~ 12

Author(s):

Virginia M. Weis ◽

E. Alan Verde ◽

Alena Pribyl ◽

Jodi A. Schwarz

Keyword(s):

Sea Anemones ◽

Larval Biology ◽

Anthopleura Elegantissima

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Some Recent Observations on the Acrorhagi of Sea Anemones

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400041448 ◽

1978 ◽

Vol 58 (3) ◽

pp. 787-788 ◽

Cited By ~ 17

Keyword(s):

Aggressive Behaviour ◽

The Body ◽

Sea Anemones ◽

Oral Disc ◽

Anthopleura Elegantissima ◽

Repeated Contact

Certain endomyarian sea anemones possess marginal spherules or acrorhagi (Stephenson, 1928) which are employed only in aggressive behaviour towards other Anthozoa. The acrorhagi can be dilated and movements of the oral disc and column bring them into contact with an adversary. Pieces of acrorhagial ectoderm adhere to the body of the adversary whilst discharging into it the large atrich nematocysts characteristic of acrorhagi. Such behaviour has been described in the European anemone Actinia equina (L.) and the Californian anemones Anthopleura elegantissima (Brandt) and Anthopleura artemisia (Dana) (Äbel, 1954; Bonnin, 1964; Francis, 1973). Aggression usually occurs only following repeated contact with a genotypically distinct anemone: mere proximity does not usually initiate any response (Francis, 1973).I have recently seen similar behaviour, apparently not recorded before, in the European anemone Anthopleura ballii (Cocks) collected from Weymouth, England. Specimens were kept in an aerated aquarium with other anemones and fed irregularly: the behaviour observed occurred between 19.00 and 22.00 h G.M.T. during August and November 1977. Following contact between two specimens of different colour varieties and the subsequent use of acrorhagi by one of them, the light-coloured passive individual immediately moved away from the dark-coloured aggressor and remained partly contracted with a ‘withered’ appearance to the tentacles for 1 week, following which it recovered (August). The same aggressor later (November) attacked a Cereus pedunculatus (Pennant), causing it to detach immediately from the substrate and to become necrotic one day later. The Cereus remained detached with the tentacles retracted and the column swollen for 5 days before it recovered.

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DNA METHYLATION PROFILING OF A CNIDARIAN-ALGAL SYMBIOSIS USING NANOPORE SEQUENCING

10.1101/2021.02.01.429278 ◽

2021 ◽

Author(s):

James L. Dimond ◽

Nhung Nguyen ◽

Steven B. Roberts

Keyword(s):

Draft Genome ◽

Genomic Region ◽

Nanopore Sequencing ◽

Sea Anemones ◽

Cpg Dinucleotides ◽

Algal Symbiosis ◽

Anthopleura Elegantissima ◽

Base Modifications ◽

Pass Through ◽

Methylation Profiling

ABSTRACTSymbiosis with protists is common among cnidarians such as corals and sea anemones, and is associated with homeostatic and phenotypic changes in the host that could have epigenetic underpinnings, such as methylation of CpG dinucleotides. We leveraged the sensitivity to base modifications of nanopore sequencing to probe the effect of symbiosis with the chlorophyte Elliptochloris marina on methylation in the sea anemone Anthopleura elegantissima. We first validated the approach by comparison of nanopore-derived methylation levels with CpG depletion analysis of a published transcriptome, finding that high methylation levels are associated with CpG depletion as expected. Next, using reads generated exclusively from aposymbiotic anemones, a largely complete draft genome comprising 243 Mb was assembled. Reads from aposymbiotic and symbiotic sea anemones were then mapped to this genome and assessed for methylation using the program Nanopolish, which detects signal disruptions from base modifications as they pass through the nanopore. Based on assessment of 452,841 CpGs for which there was adequate read coverage (approximately 8% of the CpGs in the genome), symbiosis with E. marina was, surprisingly, associated with only subtle changes in the host methylome. However, we did identify one extended genomic region with consistently higher methylation among symbiotic individuals. The region was associated with a DNA polymerase zeta that is noted for its role in translesion synthesis, which opens interesting questions about the biology of this symbiosis. Our study highlights the power and relative simplicity of nanopore sequencing for studies of nucleic acid base modifications in non-model species.

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