Population structure of the purple sea urchin Heliocidaris erythrogramma along a latitudinal gradient in south-west Australia

2013 ◽  
Vol 94 (5) ◽  
pp. 1033-1040 ◽  
Author(s):  
Dan A. Smale ◽  
Thomas Wernberg
Keyword(s):  
Sea Urchin ◽  
Survey Design ◽  
Sea Urchins ◽  
Gonad Index ◽  
Population Level ◽  
Habitat Types ◽  
Heliocidaris Erythrogramma ◽  
Purple Sea Urchin ◽  
South West ◽  
Size Condition

Sea urchins are key herbivores in many coastal ecosystems. The purple sea urchin, Heliocidaris erythrogramma, is widely distributed across temperate Australia where it exhibits considerable plasticity in feeding behaviour and ecophysiology. In this study we examined H. erythrogramma populations on subtidal reefs along ~4° of latitude in south-west Australia. We used a multi-factorial survey design to assess variability in H. erythrogramma abundances between locations (>200 km part), sites (≥1 km apart) and habitat types (reef flats and slopes). We also examined spatial variability in urchin size, condition (measured by gonad index), and the relative abundances of two co-occurring subspecies. Urchin densities were generally low and did not vary between locations, but did vary between habitat types and amongst sites. Site-level variability in urchin size and condition was also pronounced. The southernmost population comprised smaller individuals and greater relative abundance of the H. e. erythrogramma subspecies, which is abundant on the east coast of Australia. We observed no indication of population-level responses to a recent extreme warming event that impacted the wider ecology of the region, but further investigation into the effects of both gradual warming and short-term climatic events on the ecology of H. erythrogramma and other key herbivores is required.

scholarly journals Variation in purple sea urchin (Strongylocentrotus purpuratus) morphological traits in relation to resource availability

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11352
Author(s):  
Joshua G. Smith ◽  
Sabrina C. Garcia
Keyword(s):  
Sea Urchin ◽  
Sea Urchins ◽  
Strongylocentrotus Purpuratus ◽  
Food Limitation ◽  
Gonad Index ◽  
Energy Allocation ◽  
Reproductive Capacity ◽  
Mosaic Landscape ◽  
Purple Sea Urchin ◽  
Resource Limited

Flexible resource investment is a risk sensitive reproductive strategy where individuals trade resources spent on reproduction for basic metabolic maintenance and survival. This study examined morphological variation in herbivorous sea urchin grazers across a mosaic landscape of macroalgae dominated habitats interspersed with patches of sea urchin barrens to determine whether sea urchins shift energy allocation in response to food limitation. Extensive underwater surveys of habitat attributes (e.g., sea urchin density, algae cover) were paired with detailed laboratory assays (e.g., sea urchin dissections) to determine how resource abundance affects energy allocation between reproductive capacity and body structure in the purple sea urchin, Strongylocentrotus purpuratus. We found that: (1) sea urchins had a more elongate jaw structure relative to body size in habitats void of macroalgae (i.e., barrens), (2) sea urchin reproductive capacity (i.e., gonad index) was lower in barrens and the barrens habitat was primarily comprised of encrusting algae, and (3) sea urchin jaw morphology (i.e., lantern index) and reproductive capacity (i.e., gonad index) were inversely related. These results suggest that sea urchins respond to macroalgae limited environments by shifting energy allocation between reproductive capacity and modifications of the foraging apparatus, which may explain the ability of sea urchins to acquire food in resource-limited environments.

scholarly journals Effects of five southern California macroalgal diets on consumption, growth, and gonad weight, in the purple sea urchin Strongylocentrotus purpuratus

2014 ◽  
Author(s):  
Matthew C Foster ◽  
Jarrett E Byrnes ◽  
Daniel C Reed
Keyword(s):  
Sea Urchin ◽  
Sea Urchins ◽  
Strongylocentrotus Purpuratus ◽  
Macrocystis Pyrifera ◽  
Reproductive Capacity ◽  
Giant Kelp ◽  
Mixed Diet ◽  
Gonad Weight ◽  
Consumption Growth ◽  
Purple Sea Urchin

Consumer growth and reproductive capacity are direct functions of diet. Strongylocentrotid sea urchins, the dominant herbivores in California kelp forests, strongly prefer giant kelp (Macrocystis pyrifera), but are highly catholic in their ability to consume other species. The biomass of Macrocystis fluctuates greatly in space and time and the extent to which urchins can use alternate species of algae or a mixed diet of multiple algal species to maintain fitness when giant kelp is unavailable is unknown. We experimentally examined the effects of single and mixed species diets on consumption, growth and gonad weight in the purple sea urchin Strongylocentrotus purpuratus. Urchins were fed single species diets consisting of one of four common species of macroalgae (the kelps Macrocystis pyrifera and Pterygophora californica, and the red algae Chondracanthus corymbiferus and Rhodymenia californica (hereafter referred to by genus) or a mixed diet containing all four species ad libitum over a 13-week period in a controlled laboratory setting. Urchins fed Chondracanthus, Macrocystis and a mixed diet showed the highest growth (in terms of test diameter, wet weight and jaw length) and gonad weight while urchins fed Pterygophora and Rhodymenia showed the lowest. Urchins consumed their preferred food, Macrocystis at the highest rate when offered a mixture, but consumed Chondracanthus or Macrocystis at similar rates when the two algae were offered alone. The differences in urchin feeding behavior and growth observed between these diet types suggest the relative availability of the algae tested here could affect urchin populations and their interactions with the algal assemblage. The fact that the performance of urchins fed Chondracanthus was similar or higher than those fed the preferred Macrocystis suggests purple sea urchins could sustain growth and reproduction during times of low Macrocystis abundance as is common following large wave events.

scholarly journals Diverse Transformers (Trf) Protein Family in the Sea Urchin Paracentrotus lividus Act through Collaboration between Cellular and Humoral Immune Effector Arms

2021 ◽  
Author(s):  
Iryna Yakovenko ◽  
Asaf Donnyo ◽  
Or Ioscovich ◽  
Benyamin Rosental ◽  
Matan Oren
Keyword(s):  
Sea Urchin ◽  
Sea Urchins ◽  
Paracentrotus Lividus ◽  
Protein Family ◽  
Immune Gene ◽  
Immune Effector ◽  
E Coli ◽  
Purple Sea Urchin ◽  
Humoral Immune ◽  
Extended Families

Sea urchins are long-living invertebrates with a complex immune system which includes extended families of immune receptors. A central immune gene family in the sea urchins encodes for the Transformer (Trf) proteins. The Trf family was so far studied mainly in the purple sea urchin Strongylocentrotus purpuratus. In this study, we explored this protein family in the Mediterranean Sea urchin Paracentrotus lividus. The PlTrf genes and predicted proteins were found to be highly diverse and showed a typical Trf size range and structure. We found that P. lividus coelomocytes and hemolymph contain different PlTrf protein repertoires with a shared subset which specifically bind E. coli bacteria. Using FACS, we identified five different P. lividus coelomocyte sub-populations with cell surface Trf protein expression. The relative abundance of the Trf-positive cells sharply increased following immune challenge with E. coli bacteria, but not following challenge with LPS or sea urchin pathogen V. penaeicida. Finally, we demonstrated that the phagocytosis of E. coli bacteria by P. lividus phagocytes is mediated through the hemolymph and is inhibited by blocking Trf activity with anti-Trf antibodies. Together, our results suggest collaboration between cellular and humoral Trf-mediated effector arms in the P. lividus specific immune response to pathogens.

scholarly journals Sea Urchin as a Universal Model for Studies of Gene Networks

2021 ◽  
Vol 11 ◽  
Author(s):  
Leonid Adonin ◽  
Anatoliy Drozdov ◽  
Nickolai A. Barlev
Keyword(s):  
Signaling Pathways ◽  
Sea Urchin ◽  
Gene Networks ◽  
Regulatory Networks ◽  
Sea Urchins ◽  
Cell Cycle Control ◽  
Model Organism ◽  
Purple Sea Urchin ◽  
Main Components ◽  
Embryonic Signaling

The purple sea urchin Strongylocentrotus purpuratus has been used for over 150 years as a model organism in developmental biology. Using this model species, scientists have been able to describe, in detail, the mechanisms of cell cycle control and cell adhesion, fertilization, calcium signaling, cell differentiation, and death. Massive parallel sequencing of the sea urchin genome enabled the deciphering of the main components of gene regulatory networks during the activation of embryonic signaling pathways. This knowledge helped to extrapolate aberrations in somatic cells that may lead to diseases, including cancer in humans. Furthermore, since many, if not all, developmental signaling pathways were shown to be controlled by non-coding RNAs (ncRNAs), the sea urchin organism represents an attractive experimental model. In this review, we discuss the main discoveries in the genetics, genomics, and transcriptomics of sea urchins during embryogenesis with the main focus on the role of ncRNAs. This information may be useful for comparative studies between different organisms, and may help identify new regulatory networks controlled by ncRNAs.

scholarly journals Effects of five southern California macroalgal diets on consumption, growth, and gonad weight, in the purple sea urchin Strongylocentrotus purpuratus

2014 ◽  
Author(s):  
Matthew C Foster ◽  
Jarrett E Byrnes ◽  
Daniel C Reed
Keyword(s):  
Sea Urchin ◽  
Sea Urchins ◽  
Strongylocentrotus Purpuratus ◽  
Macrocystis Pyrifera ◽  
Reproductive Capacity ◽  
Giant Kelp ◽  
Mixed Diet ◽  
Gonad Weight ◽  
Consumption Growth ◽  
Purple Sea Urchin

Consumer growth and reproductive capacity are direct functions of diet. Strongylocentrotid sea urchins, the dominant herbivores in California kelp forests, strongly prefer giant kelp (Macrocystis pyrifera), but are highly catholic in their ability to consume other species. The biomass of Macrocystis fluctuates greatly in space and time and the extent to which urchins can use alternate species of algae or a mixed diet of multiple algal species to maintain fitness when giant kelp is unavailable is unknown. We experimentally examined the effects of single and mixed species diets on consumption, growth and gonad weight in the purple sea urchin Strongylocentrotus purpuratus. Urchins were fed single species diets consisting of one of four common species of macroalgae (the kelps Macrocystis pyrifera and Pterygophora californica, and the red algae Chondracanthus corymbiferus and Rhodymenia californica (hereafter referred to by genus) or a mixed diet containing all four species ad libitum over a 13-week period in a controlled laboratory setting. Urchins fed Chondracanthus, Macrocystis and a mixed diet showed the highest growth (in terms of test diameter, wet weight and jaw length) and gonad weight while urchins fed Pterygophora and Rhodymenia showed the lowest. Urchins consumed their preferred food, Macrocystis at the highest rate when offered a mixture, but consumed Chondracanthus or Macrocystis at similar rates when the two algae were offered alone. The differences in urchin feeding behavior and growth observed between these diet types suggest the relative availability of the algae tested here could affect urchin populations and their interactions with the algal assemblage. The fact that the performance of urchins fed Chondracanthus was similar or higher than those fed the preferred Macrocystis suggests purple sea urchins could sustain growth and reproduction during times of low Macrocystis abundance as is common following large wave events.

Estrogen administration to the edible sea urchin Paracentrotus lividus (Lamarck, 1816)*

Zoosymposia ◽  
2012 ◽  
Vol 7 (1) ◽  
pp. 247-254 ◽  
Author(s):  
SILVIA MERCURIO ◽  
MICHELA SUGNI ◽  
DENISE FERNANDES ◽  
CINTA PORTE ◽  
MARIA DANIELA CANDIA CARNEVALI
Keyword(s):  
Sea Urchin ◽  
Sea Urchins ◽  
Gonad Index ◽  
Hormonal Treatment ◽  
Paracentrotus Lividus ◽  
Maturation Stage ◽  
Physiological Values ◽  
Estrogen Administration

Despite the extensive use of sea urchins in embryology, the hormonal mechanisms regulating echinoid reproductive pro­cesses are scarcely known. This research is focused on the role of estradiol (E2), whose presence and seasonal variations in different echinoderm tissues have been previously reported. Three different concentrations of E2 were administered (via peristomial injection, 2/week) to adult specimens of the sea urchin Paracentrotus lividus for 2 and 12 weeks. The lowest concentration was close to physiological values, previously measured in field specimens. Despite the increase of circulating E2 in the coelomic fluids, neither short- nor long-term hormonal treatment induced marked variations in the considered reproductive parameters. The Gonad Index appeared to be more influenced by the feed intake than by E2. Similarly, the maturation stage of the gonads was not markedly affected by E2 injection, although some sex-specific dif­ferences could be observed: treated females never reached the maximum maturation stage compared to controls, although this was observed in males injected with the lowest E2 concentration. Although further research is needed to confirm our observations, according to the present study E2 does not markedly influence echinoid reproduction and, particularly, it does not promote female maturation, as reported for vertebrates and suggested for asteroid echinoderms.

scholarly journals The Effects of Environmental Factors and Husbandry Techniques on Roe Enhancement of the New Zealand Sea Urchin, Evechinus chloroticus

2021 ◽  
Author(s):  
◽  
Philip James
Keyword(s):  
New Zealand ◽  
Sea Urchin ◽  
Water Movement ◽  
Sea Urchins ◽  
Seawater Temperature ◽  
Gonad Index ◽  
Economic Feasibility ◽  
Reproductive Stage ◽  
Gonad Growth ◽  
Gonad Size

<p>The roe of sea urchins (Echinodermata: echinoidea) is a prized seafood in a number of countries around the world, including New  Zealand. Increasing fishing pressure on world sea urchin stocks has failed to meet demand. This has led to increasing worldwide interest in roe enhancement of sea urchins. In New Zealand kina (Evechinus chloroticus) have also been heavily fished. However, there are large numbers of poor quality (low gonad index or GI) kina found in kina barrens which are uneconomic to harvest due to low returns. The primary aim of this research was to identify the key holding and environmental conditions for roe enhancement of E. chloroticus to assist in the development of a roe enhancement industry for E. chloroticus to utilise this resource. A series of experiments testing the optimal holding conditions for E. chloroticus in both land- and sea-based holding systems showed that culture depth (3 and 6 m) and removal of the urchins from the water three times per week had no significant effect on gonad growth or urchin mortality. However, exposing E. chloroticus to increased water movement resulted in significantly greater gonad growth in 12 weeks. Increasing water movement is believed to increase the available dissolved oxygen and facilitate the removal of metabolites from around the urchins. Gonad development was not negatively impacted at the maximum stock density tested (6 kg urchin m-2 of internal surface area) and this density is recommended. There are significantly lower running and maintenance costs when E. chloroticus are enhanced in sea-based compared to land-based systems but a full economic analysis is required to assess which is likely to be the more economical option for future roe enhancement. A period of 9 to 12 weeks appears to be the optimal period for roe enhancement in terms of the maximum increase in GI in the shortest time period. Repeated experiments over a 12 month period showed that food availability was the primary driver of roe enhancement (i.e. increase in gonad size) in E. chloroticus. This is followed by seawater temperature, which drives much of the seasonal variation in the gonad size that is observed in wild urchins. This is likely to be due to increased food consumption at higher temperatures. The reproductive stage of E. chloroticus had very little effect on the increase in gonad size of enhanced urchins other than in autumn when gonad growth was slightly lower than in all other seasons. Optimal gonad growth in this study was obtained at 18oC, which was the highest temperature tested. Higher temperatures also resulted in an increase in the rate of progress of the gametogenic cycle of E. chloroticus whilst lower temperatures tended to slow the rate of progress. The effects of temperature on gonad growth (i.e. increased growth at higher temperatures) were consistent across seasons. Photoperiod had minimal effect on gonad growth and the reproductive stage of the urchins over periods of 12 weeks. Photoperiod may still affect gametogenesis of E. chloroticus over longer periods. Low GI kina appear to be capable of significantly larger increases in GI in 10-week periods than high GI kina, as a result of their higher tolerance to stress. This thesis has contributed to improving the technical and economic feasibility of roe enhancement of kina (E. chloroticus) in New Zealand.</p>

Sign in / Sign up

Export Citation Format

Share Document