Competent Larvae Research Articles

Optimizing initial stocking densities of wild coral spawn slicks for mass production of larvae and settled corals for restoration

Mass culturing coral larvae collected from spawn slicks during spawning events and rearing them directly on reefs is an important method for coral reef restoration as it utilizes high genetic diversity and is readily upscaled. Understanding optimal initial stocking densities in mass cultures is, therefore, central to optimizing larval production efficiency. Yet, no studies have focused on optimizing initial stocking densities while coral embryos are still floating, despite the influence of density‐dependent effects during larval culturing. This study aimed to (1) explore initial stocking densities based on slick coverage and (2) determine the effects of initial densities on embryo development to coral settlement and early post‐settlement survival. Wild coral spawn slicks were collected at Lizard Island and reared at different combinations of slick coverage and density based on tank volume. Immediate density‐dependent effects were observed in treatments with 45% slick coverage, which had lower abundances of embryos 12 hours post‐spawning. The 12‐hour embryo densities ranged from 1.7 to 10.7 mL−1 and continued to display a negative relationship between density and survival of developing larvae. Overall, a density of approximately 5.1 embryos mL‐1 was the optimal stocking density for larval survival to competency (16.5%). The proportion of settlement and early post‐settlement survival was negatively correlated with higher initial densities, while a positive relationship was observed between the abundance of competent larvae and those settled, including initial settlers and 2‐month‐old recruits. These results highlight the importance of both larval quality and supply, and opportunities for site and system‐specific optimization of larval production in future work.

Assessing methods of enhancement for New Zealand blackfoot abalone (Haliotis iris) populations affected by mass mortality

ABSTRACT With the collapse of global populations, New Zealand has one of the last wild abalone fisheries. The blackfoot abalone (Haliotis iris) supports important customary, commercial and recreational harvests, but environmental stressors and overfishing have prompted restoration and stock enhancement efforts. We used field surveys to quantify effects of the 2018 commercial outplanting of 167,000 hatchery-raised juvenile abalone following the catastrophic Kaikōura earthquake. We tested alternative enhancement methods by outplanting swimming larvae and rocks with settled post-larvae. Annual surveys at seven sites found that outplanted juveniles comprised 12% of the sampled population after three years, amid unexpectedly high natural recruitment. Recaptured outplants grew well at c. 25 mm yr−1 but showed poor growth at two densely populated sites. After three years, >50% of recaptured individuals had likely reached sexual maturity. Outplanting 200,000 competent swimming larvae into natural habitats had no effect after three months compared to controls. However, the outplanting of rocks settled with larvae resulted in a significantly greater density of small (≤15 mm) recruits compared to controls, signalling potential for this method as a practical and scalable enhancement strategy. The insights from this research help clarify the benefits and limitations of three stock enhancement methods and inform future efforts.

Influence of physico-chemical parameters on the settlement of competent larvae of cultured sea urchin, Paracentrotus lividus

Achieving efficient metamorphosis and settlement of larvae is a major bottleneck in the culture of sea urchins; therefore, in order for culture operations to be economically viable, it is urgent to optimize this crucial step under captive conditions. This study aimed to investigate how various parameters, including temperature, salinity, light cycle, and inducer type, affect the settlement of competent P. lividus larvae. Three different salinities (35, 30, 25‰), three temperatures (25, 20, 15 °C), four light conditions (16/8, 12/12, 24/0 and 0/24) and five types of biofilms (three of “natural” origin and the other two from monospecific collection cultures) were tested. The results suggest a relationship between low salinity and decreased survival and settlement rates. Conversely, the photoperiod appears not to have significant influence over survival and settlement rates. It appears that specific temperatures did not affect rates of survival and settlement, rather it was the deviation from initial culture temperature that is responsible for these rates. Finally, the multispecific inoculum of benthic diatoms showed a higher survival and settlement rate and lower mortality rate compared to monospecific inoculum.

Influence of Pediveliger Larvae Stocking Density on Settlement Efficiency and Seed Production in Captivity of Mytilus galloprovincialis in Amsa Bay, Tetouan.

In mussel hatchery systems, the settlement process is a crucial element influencing seed yield. The current study assayed the influence of five densities of competent pediveliger larvae on settlement success and post-larvae production. We showed an inverse relationship between density and settlement efficiency, e.g., an attachment success of 99.4% at the lowest density (35 larvae/cm2) but only 9% at the highest density (210 larvae/cm2). However, post-larvae production was higher at intermediate larvae densities (70 larvae/cm2). The reimplementation of treatments upon post-larvae density after 6 weeks post settlement showed that the lowest-density groups bore both the highest post-larvae growth rate (22.24 ± 4.60 µm/day) and the largest head batch (48% of the size distribution), as compared to the higher-post-larvae-density groups. These results highlight the importance of optimizing both pediveliger larvae density and post-larvae density, to maximize high-quality seed yield in local hatcheries. Current rearing technologies would assure a timely commercial seed production to protect natural sea rocky beds in Alboran Sea coasts.

Numerical Study of Turbulent Wake of Offshore Wind Turbines and Retention Time of Larval Dispersion

Offshore Wind Farm (OWF) foundations are considered to have a potential impact on the larval dispersion of benthic species. This study focused on OWFs’ impacts on larval dispersion, considering factors such as the foundation type, flow velocity, flow direction, and release type using numerical modelling. At the scale of monopile and gravity-based foundations, a combination of two numerical models was used: the Eulerian model (OpenFOAM), solving the 3D Navier–Stokes equations for computing the hydrodynamics, and the Lagrangian model (Ichthyop), solving the advection–diffusion equation for the larval dispersion simulations. The validation model tests were evaluated with experimental data as a first step of the study. Accurate results were achieved, yielding a Turbulent Kinetic Energy (TKE) Root-Mean-Squared Error (RMSE) in the range of 6.82–8.27 ×10−5kg/m·s2 within the refined mesh, with a coefficient of determination (R2) approaching unity. For the second phase, more-realistic simulations were modelled. Those simulations demonstrated turbulent wakes downstream of the foundations and horseshoe vortex formations near the bottom. A larval dispersion was simulated using passive particles’ motion. Vertical flumes in the wake with particles experiencing both upward and downward motions, impacting the fall velocities of the particles, were observed. The influence of gravity-based foundations might lead to a stepping-stone effect with a retention time of up to 9 min, potentially allowing the settlement of competent larvae. In a similar geometry with an angular spring tide velocity, 0.4% of particles were trapped.

Induction of larval settlement in crown-of-thorns starfish is not mediated by conspecific cues

Population irruptions of crown-of-thorns starfish (COTS; Acanthaster spp.) remain a major cause of coral reef degradation throughout the Pacific and Indian Oceans and are inherently modulated by larval settlement and recruitment success. Gregarious larval settlement, as exhibited by many other ecologically important marine invertebrates, can catalyse population growth and replenishment. However, whether conspecific cues induce or influence the settlement of COTS larvae remains a critical information gap. This experimental study examined the induction of COTS settlement in response to a range of conspecific cues associated with early- and late-stage herbivorous juveniles, corallivorous juveniles and adults. Competent COTS larvae were generally not induced to settle by the presence of conspecifics or cues associated with conspecifics, while the settlement success of COTS in the presence of coralline algae was not inhibited or enhanced by adding conspecific conditioned seawater. Rather than being reinforced by gregarious settlement, the recruitment of COTS populations appears dependent on associative settlement cues (i.e., coralline algae and/or associated microbial communities) signalling suitable benthic habitat.

Response of true limpet Patella aspera (Patellogastropoda) pediveliger larvae to a range of settlement cues

Context Settlement and metamorphosis are key processes influencing the natural recruitment and aquaculture production of aquatic organisms. Recruitment requirements in limpets (Patellogastropoda) are mostly unknown, because of the lack of reliable settlement inducers. Aims This study tested the reliability of different cues as settlement inducers for competent larvae of the economically valuable Patella aspera. Methods Natural crustose coralline algae (CCA) and biofilms of the benthic diatom Navicula salinicola were tested as positive controls. The following four pharmacological agents were tested as chemical inducers in a wide range of concentrations: gamma-aminobutyric acid (GABA), acetylcholine (ACH), 3-isobutyl-1-methylxanthine (IBMX) and potassium chloride (KCl). Settlers were identified by the velum loss and teleoconch development. Key results CCA were strong settlement cues in all the assays. Contrary to previous hypotheses, GABA was a weak inducer with a peak effect at 10−5 M. Neither the diatom biofilms nor the other pharmacological agents (ACH, IBMX and KCl) promoted the settlement response. All pharmacological agents at high concentrations influenced larval behaviour. Conclusions CCA were reliable positive controls and settlement inducers for the production of post-larvae. With regard to pharmacological agents, P. aspera showed restrictive settlement requirements that should be considered for ecological and aquaculture studies in other limpet species. Implications This method allows the study of the settlement biology of limpets. It provides a positive control and integrates animal monitoring and comparative response to other cues.

EFFECT OF LARVAL DENSITY AND DIET ON THE GROWTH AND SURVIVAL OF Perna perna MUSSELS IN RECIRCULATION SYSTEM (RAS).

This study evaluated the effect of initial larval stocking density and microalgae concentration in the diet on the growth and the number of competent larvae (number of live larvae at the end of the experiment retained on a sieve with mesh size of 210 µm) of Perna perna in a water recirculation system (RAS). The experiment was conducted using a completely randomized design and factorial scheme, with one factor being the food concentration at three levels (low: between 1.26 to 2.19, medium: between 2.36 to 3.94 and high: 5.03 to 7.29 x 104 cells mL⁻¹) and the second factor being the larval culture density, also at three levels (20, 80 and 200 larvae mL⁻¹), with 3 replications in each treatment. Larvae fed with the diet with low and high concentrations did not reach competence (210 µm) in 16 days. However, for larvae fed with the medium concentration (2.36 to 3.94 x 104 cells mL⁻¹), the average percentage of competent larvae, on day 16, was 21.8% ± 7.45, 27.4% ± 9.91 and 0.80% ± 0.26 at the densities 20, 80 and 200 larvae mL-1, respectively.

Pile driving and drilling underwater sounds impact the metamorphosis dynamics of Pecten maximus (L., 1758) larvae

One of the biggest challenges of the 21st century is to reduce carbon emissions and offshore wind turbines seem to be an efficient solution. However, during the installation phase, high levels of noise are emitted whose impacts remain not well known, particularly on benthic marine invertebrates displaying a bentho-planktonic life-cycle. For one century, larval settlement and subsequent recruitment has been considered as a key topic in ecology as it determines largely population renewal. Whereas several recent studies have shown that trophic pelagic but also natural soundscape cues could trigger bivalve settlement, the role of anthropogenic noise remains poorly documented. Therefore, we conducted experiments to assess potential interacting effects of diet and pile driving or drilling sounds on the great scallop (Pecten maximus) larval settlement. We demonstrate here that pile driving noise stimulates both growth and metamorphosis as well as it increases the total lipid content of competent larvae. Conversely, drilling noise reduces both survival and metamorphosis rates. For the first time, we provide evidence of noise impacts associated to MREs installation on P. maximus larvae and discuss about potential consequences on their recruitment.

RNA-seq analysis reveals the effect of the metamorphic cue (juvenile oysters) on the Rapana venosa larvae

As a vital developmental event, metamorphosis controls the population dynamics of most marine invertebrates and affects the breeding of economic shellfish. Rapana venosa is an economically important species in China, but artificial aquaculture has hampered its metamorphosis process. Previous studies have found that juvenile oysters can effectively induce the metamorphosis of R. venosa, but the specific induction mechanism is not clear. Here, we investigated the mechanism underlying the response of R. venosa to juvenile oysters through the RNA-seq analysis. In this study, the gene set responses to metamorphosis cues (juvenile oysters) in R. venosa were identified, and GO and KEGG enrichment analyses were further performed on these gene sets. The results showed that the expression of the prototype of the class of immediate early genes, the transcription factor AP-1, was rapidly and significantly increased, and the molecular chaperone of NOS, HSP90, exhibited lower expression in the M12 group than in the control group. In contrast, the expression of inhibitors of apoptosis (IAPs) was significantly increased upon exposure to juvenile oysters. Additionally, the Wnt signaling pathway and MAPK signaling pathway were enriched in the trend analysis. These pathways may also play critical regulatory roles in the response to juvenile oysters. Taken together, the results show that competent larvae rapidly respond to the inducing effects of oysters via some immediate early genes, such as the transcription factor AP-1, which may further regulate downstream pathways such as the MAPK signaling pathway to cause subsequent changes, including a decrease in HSP90 and an increase in IAPs. These changes together may regulate the metamorphosis of R. venosa. This study provides further evidence that juvenile oysters are the metamorphosis cues of R. venosa, which may enhance our understanding of the metamorphosis mechanism in this marine invertebrate.

The presence and distribution of gamma-aminobutyric acid and dopamine during the developmental stages of the sea cucumber, Holothuria scabra, with emphasis on settlement organs.

In the sea cucumber, Holothuria scabra, the competent larvae require main settlement organs (SOs), including the ciliary bands (CiBs), tentacles (Ts), podia (PDs), and cues from neurotransmitters, including gamma-aminobutyric acid (GABA) and dopamine (DA), for successful settlement. In the present study, we investigated the spatial distribution of GABA and DA in the developmental stages of H. scabra, with special emphasis on SOs by detecting immunoreactivity (-ir) against these two neurotransmitters. Strong GABA-ir and DA-ir cells and fibers were specifically detected in several SO structures, including CiBs, CiB cells (CiBCs), and long cilia (LCi), of H. scabra larvae. Additionally, we found intense GABA-ir and DA-ir cells in the epithelial lining of bud-papillae (BP) and mesothelium (Me) in the stem (S) region of Ts in larvae and juveniles. Intense GABA-ir and DA-ir were observed in the epineural nerve plexus (ENP) and hyponeural nerve plexus (HNP) of Ts in H. scabra pentactula and juvenile stages. Staining for these two neurotransmitters was particularly intense in the PDs and their nerve fibers. We also found significant changes in the numbers of GABA-ir and DA-ir-positive cells and intensities in the CiBs, Ts, and PDs during the developmental stages. Taken together, we are the first to report on the existence and distribution of GABAergic and dopaminergic systems in structures associated with the settlement. Our findings provide new and important insights into the possible functions of these two neurotransmitters in regulating the settlement of this sea cucumber species.

Integrated mRNA and miRNA transcriptomic analysis reveals the response of Rapana venosa to the metamorphic inducer (juvenile oysters)

Metamorphosis, as a critical developmental event, controls the population dynamics of most marine invertebrates, especially some carnivorous gastropods that feed on bivalves, whose population dynamics not only affect the maintenance of the ecological balance but also impact the protection of bivalve resources; therefore, the metamorphosis of carnivorous gastropods deserve attention. Here, we investigated the mechanism underlying the response of the carnivorous gastropod Rapana venosa to its metamorphic inducer juvenile oysters through integrated analysis of miRNA and mRNA profiles. According to the results, we speculated that the AMPK signaling pathway may be the critical regulator in the response to juvenile oysters in R. venosa competent larvae. The NF-kB and JAK-STAT signaling pathways that regulated apoptosis were also activated by the metamorphic inducer, which may result in the degeneration of the velum. Additionally, the significant changes in the expression of the SARP-19 precursor gene and protein cibby homolog 1-like gene may indicate that these signaling pathways also regulate growth and development during metamorphosis. This study provides further evidence that juvenile oysters can induce metamorphosis of R. venosa at the transcriptional level, which expands our understanding of the metamorphosis mechanism in carnivorous gastropods.

Scoping Bay Scallop Restoration in Rhode Island: A Synthesis of Knowledge and Recommendations for Future Efforts

The bay scallop is a culturally important species that once supported significant fisheries along the U.S. east coast. Mass population declines in the 1900s led to a nearly total loss of the fishery in most states, including Rhode Island. In certain areas, intensive, long-term restoration efforts have effectively restored scallop populations and fisheries on a small scale, but indicate that such plans must be scoped specific to systems. In an effort to support the development of an upcoming Rhode Island Shellfish Restoration Plan, relevant knowledge on bay scallops was collated and summarized, and this information was used to create a habitat suitability index that can act as a guide to identify suitable restoration sites for renewed bay scallop restoration efforts in one of the largest coastal salt ponds in Rhode Island, Point Judith Pond. Point Judith Pond was once the epicenter of the bay scallop fishery in the state of Rhode Island, and the ranked index suggests multiple sites throughout the pond are likely to once again provide adequate habitat for bay scallops. Restoration strategies such as caged spawner sanctuaries and the release of competent larvae in areas identified as suitable by the index are recommended for future restoration planning of this species.

Apoptotic Processes Precede Infection with Symbionts in a Pogonophoran Lavrae (Siboglinidae, Annelida)

The fine structure of the body wall and gut was for the first time studied in the competent larvae of the frenulate pogonophoran Siboglinum fiordicum. Mass apoptosis of cell nuclei was observed in the dermo-muscular body wall and coelomic epithelium. Apoptotic nuclei were found in both cell cytoplasm and outside of the larval body. In the latter case, each nucleus was surrounded by the plasmalemma, and the entire cluster was covered with the cuticle. Cells of the larval gut retained the usual structure with the cytoplasm filled with numerous yolky granules and the nucleus displaying usual morphology. Similar apoptotic processes have been described in vestimentiferans and found to be initiated by penetration of symbiotic bacteria through the integument into the dorsal mesentery. The process of apoptotic rearrangement of body wall cells and the formation of unique symbiosis with bacteria were assumed to be time-spaced in S. fiordicum, occurring sequentially rather than simultaneously, unlike in vestimentiferans.

Larvae of a marine gastropod and a marine bivalve share common gene expression signatures during metamorphic competence

Many aquatic invertebrates undergo an indirect development, a biphasic life cycle which encompasses the transformation of free-swimming larvae into benthic juveniles via settlement and metamorphosis. During this transition, metamorphic competence is a crucial developmental stage that allows larvae to swim and feed in the planktonic realm while retaining the ability to settle and metamorphose in response to environmental cues. Although there have been substantial efforts to decipher the molecular mechanisms underlying this event in several molluscan species, the conserved biological pathways that are crucial to enable this transition across species are not well understood. Here, we performed a comparative analysis of the developmental transcriptomes between bivalve Crassostrea gigas and gastropod Rapana venosa. We particularly explored the common gene expression signatures that may underlie their larval competence. We showed that, although the developmental transcriptomes differed remarkably between C. gigas and R. venosa, they likely shared a plethora of genes (n = 690) that exhibited similar expression signatures during their larval competence. Gene Ontology enrichment and expression analyses further indicated that competent larvae of both species exhibited up-regulation of pathways associated with response to stimuli, metal ion binding and transport, and neuronal development, but showed down-regulation of pathways that were mainly involved in cilium assembly and organ development. Using oyster and whelk as models, our study suggests that regulation of these conserved pathways is crucial for their subsequent settlement and metamorphosis and may represent a universal mechanism that enables the pelagic-to-benthic transition in a broader range of marine invertebrates.

Allochthonous subsidies drive early recruitment of a subtropical foundation species

Terrestrial nutrients flushed to sea via coastal runoff may provide a trophic subsidy to filter‐feeders, which might be particularly relevant in oligotrophic waters. In this study, we investigated how allochthonous subsidies might modulate the settlement dynamics of the mytilid Brachidontes solisianus, a space monopoliser in subtropical Brazilian shores. We used fatty acid trophic markers to identify the dietary subsidies to nearshore waters during wet and dry periods, and integrated them with key ecological drivers (temperature, rainfall) and physiological factors (nutritional status, size at settlement) acting on early life stages. Like other mytilids, for B. solisianus primary settlement can be followed by resuspension and reattachment (secondary settlement). A higher share of primary settlers may signal localized recruitment, while a larger contribution of secondary settlers would indicate increased migration rates. Through redundancy analyses we found that rainfall was correlated with 1) nearshore fatty acid trophic markers of land origin and 2) the frequency of primary settlers during the wet period, when the share of terrestrial inputs was also highest (13% of nearshore suspended matter). Conditions appeared favorable to localized recruitment through trophic settlement triggers, as settlement pulses of pelagic drifters followed heavy rains. Further, lipid analyses of pediveligers revealed that during the dry period these competent larvae selectively incorporated the essential 22:6ω3 docosahexaenoic acid (DHA) into membrane phospholipids at the expense of reserve lipids, suggesting a dietary deficit. Secondary dispersal also prevailed, indicating that the chance for relocation through secondary migrations during dry periods is likely higher. Overall, our results suggest that coastal runoff leads to allochthonous trophic subsidies in the form of organic‐rich plumes which may strongly modulate the settlement rate and dispersal potential of B. solisianus. Subsidies from land to coastal waters may thus be critical for the stability of benthic communities in regions of low marine primary production.

Methodologies for Patellid Limpets’ Aquaculture: From Broodstock Management to Juveniles

The production of cultured limpets is a recent research field contributing to aquaculture diversification, focusing on low trophic species while reducing the carbon footprint. Limpets are gastropods that colonize rocky substrates and are mostly present on tidal and subtidal shores. This animal group is in high commercial demand and is endangered in several regions. The aquaculture production of limpets has been traditionally challenging. The most successful reproduction method has been gonadal dissection, as artificial spawning induction has shown limited success to date. Moreover, methods for larval culture, settlement, and juvenile growth have been poorly developed and remain largely unknown. In recent years, advances in this field have led to the optimization of methods to enhance larval production, larval culture, settlement induction of competent larvae, and management of post-larvae and juveniles. The present manuscript reviews these advances, obtained within the framework of AQUAINVERT project, focusing on broodstock management, gametes release, larval production, larviculture, settlement, and grow-out of post-larvae, and providing an update on the actual state of the art in limpets’ aquaculture.

Effect of water recirculation rate and initial stocking densities on competent larvae and survival of the Pacific oyster Crassostrea gigas in a recirculation aquaculture system

Effect of water recirculation rate and initial stocking densities on competent larvae and survival of the Pacific oyster Crassostrea gigas in a recirculation aquaculture system

Identification and characterization of olfactory receptor genes and olfactory perception in rapa whelk Rapana venosa (Valenciennes, 1846) during larval settlement and metamorphosis.

The rapa whelk Rapana venosa, an economically important marine fishery resource in China but a major invader all over the world, changes from a phytophagous to a carnivorous form following settlement and metamorphosis. However, the low settlement and metamorphosis rates (<1%) of larvae limit the abundance of R. venosa. This critical step (settlement and metamorphosis) remains poorly characterized but may be related to how larvae perceive the presence of shellfish, their new source of food. Here, we report that larvae may use olfactory perception to sense shellfish. Olfactory receptor (OR) genes are involved in odor sensing in animals. We identified a total of 463 OR genes, which could be grouped into nine clades based on phylogenetic analysis. When assessing the attraction of larvae at different developmental stages to oyster odor, R. venosa showed active settlement and metamorphosis behavior only at the J4 stage (competent larva, 1000-1500 μm shell length) and in the presence of shellfish odor at the same time. Expression of OR gene family members differed between stage 2 (four-spiral whorl stage) and stage 1 (single- to three-spiral whorl stage), indicating significant changes in the olfactory system during larval development. These findings broaden our understanding of olfactory perception, settlement, and metamorphosis in gastropods and can be used to improve R. venosa harvesting, as well as the sustainable development and utilization of this resource.

Temperature and reduced pH regulate stress and biomineralization gene expression in larvae and post-larvae of the sand dollar Dendraster excentricus

ABSTRACT Seawater temperature, oxygen, salinity and pH are important abiotic factors, changes in which can generate stress in marine organisms. Subtidal and intertidal species, such as the sand dollar Dendraster excentricus, are daily exposed to stressors against which they have developed survival mechanisms to face environmental challenges. Analysing the expression of some key genes in response to stress factors due to changes in temperature and pH, especially in the early stages of development, opens a window of knowledge on the effect that these stressors have on benthic marine organisms. In the present work larvae and post-larvae of D. excentricus were exposed to high temperature and low pH scenarios. Survival, size and gene expression of five genes, involved in both stress response (hsp70 IV and hsp90 beta-like) and biomineralization for skeletogenesis (sm29, sm30A, carbonic anhydrase 14-like and mitochondrial proton/calcium exchanger protein LOC575637), were analysed in 4-, 6-, 8-arms, competent larvae and post-larvae. Survival of stressed larvae and post-larvae presented a significant decrease, up to 37% in some stages. A size reduction of almost 30 μm was observed when larvae were exposed to stressful conditions, except in competent larvae and in post-larvae where no significant changes were detected. After stress treatments, transcripts of hsp90 beta-like were up-regulated in all larval stages but hsp70 IV transcripts were not. Under tested stressful conditions sm29 and sm30A expression was down-regulated in larvae and post-larvae, while carbonic anhydrase 14-like and LOC575637 expressions were up-regulated. It is evident that tolerance to changes in seawater temperature and pH has a direct effect on metabolic functions of D. excentricus larvae and post-larvae, which depends on the developmental stage. If laboratory results are extrapolated to marine ecosystems, it is possible that populations of this structuring organism may be disturbed with subsequent damage to ecosystem balance, until resilient organisms acclimatize and adapt to their changing habitats.