Mass Spawning Research Articles

Monitoring and assessing a 2-year outbreak of the corallivorous seastar Acanthaster planci in Ari Atoll, Republic of Maldives.

Outbreaks of the corallivorous crown-of-thorns seastars have received increasing attention due to their negative impacts on coral reefs in the Indo-Pacific Ocean. However, outbreaks in remote and dislocated islands are still poorly understood. This study aims to begin filling informational gaps regarding outbreaks of Acanthaster planci in the remote islands of the central Ari Atoll, Republic of Maldives. The population of A. planci was monitored during three periods over 2years (2015-2016) to evaluate variations in abundance and to characterise size structure and feeding behaviour. The outbreak appeared to be severe and active throughout the entire study period. The size structure analysis revealed a multimodal distribution dominated by individuals between 20 and 30cm, suggesting that the outbreak may have resulted from a few nearby mass spawning events. Additionally, the most abundant live coral was Porites, which was also the most consumed genus; however, the electivity index showed a preference for corals of the genera Favites and Pavona. Finally, we also highlighted the need for more geographically extended surveys to better understand local patterns regarding outbreaks of A. planci in the Republic of Maldives.

Split spawning realigns coral reproduction with optimal environmental windows

Split spawning in coral populations occurs when gamete maturation and mass spawning are split over two consecutive months. While split spawning has been observed at many reefs, little is known about the frequency and significance of these events. Here we show that split spawning occurred frequently and predictably over a decade at Scott Reef. Split spawning overlays the biannual spawning pattern in the region and occurs when the full moon falls in the first week of the usual spawning month, or the last week of the previous month. Additionally, in split years most species have their main spawning event after a 13-month lunar cycle, in the month following the usual spawning month. Without split spawning, spawn dates would shift by ~10 days each year to occur outside of optimal environmental windows. Our results suggest that split spawning is driven by a disconnect between lunar and seasonal cues, and is analogous with a ‘leap year’ in coral reproduction, realigning spawning dates with favourable conditions for reproduction.

Timing of mass spawning in corals: potential influence of the coincidence of lunar factors and associated changes in atmospheric pressure from northern and southern hemisphere case studies

Synchronised multispecies mass spawning events are striking features of reproduction in corals. This synchronous gamete release of thousands of animals over vast stretches of reef is thought to be cued by rhythms of the Moon. However, the mechanisms are not fully understood. We propose an explanation that may contribute to understanding this mechanism, that spawning is triggered by the coincidence of two factors, each in different lunar rhythms. We investigate this proposal in case studies using seven years of coral spawning data from two locations: Kochi, Japan and Lizard Island, Australia. Our calculations show that a feature in a lunar synodic rhythm (the third quarter) will synchronise with a feature in a lunar non-synodic rhythm (the zero declination) usually once, although occasionally twice in a year. Supported by data on the date of spawning from the two locations, we suggest that this coincidence of lunar factors exerts an important influence on the timing of annual mass spawning in corals. This coincidence may be associated with low atmospheric pressure. Spawning at the time of the third lunar quarter may favour fertilisation success due to the reduced currents during neap tides associated with the lower gravitational pressure of the lunar quarters.

Transmission of Pseudoloma neurophilia in Laboratory Zebrafish (Danio rerio) When Using Mass Spawning Chambers and Recommendations for Chamber Disinfection.

Pseudoloma neurophilia, a microsporidium that primarily infects neural tissues, is a common pathogen in laboratory zebrafish. The risk of parasite transmission with different spawning apparatuses and the effectiveness of disinfection are unknown. In this study, we spawned uninfected zebrafish with P. neurophilia-infected zebrafish in either 50 L mass spawning chambers (MSCs) or 1 L standard breeding tanks (BTs). Fish were spawned once or thrice, with and without chamber disinfection between uses, to evaluate risk of vertical and horizontal transmission. Six disinfection protocols were tested to determine which effectively eliminated residual spores. We demonstrated that three consecutive uses of an MSC significantly increased the risk of transmission to other fish when compared to the use of BTs or only one spawning event in an MSC (both p < 0.0001). Vertical transmission was not detected with any method. Disinfection with ∼100 ppm bleach soak (pH ∼7.0), 75 ppm Wescodyne® soak, and 175 ppm Wescodyne Plus spray was 100% effective in eliminating spores from the MSCs. Disinfection of MSCs before spawning did not decrease P. neurophilia transmission when infected fish remained present in the breeding population. Researchers should avoid using endemically infected fish in MSCs to minimize transmission of pathogens within their colonies.

Parentage assignment of a hormonally induced mass spawning in Japanese eel (Anguillla japonica)

Anguillid eels are a high value species for aquaculture in East Asian countries, but natural stocks of eels have been decreasing. Mass production of glass eels is one of the most effective ways to solve this problem. Genetic improvements will become important to establish mass production of glass eels in the near future. However, there is a lack of basic information, such as parentage assignments, for implementing an eel breeding program. In this study, we aimed to understand the parentage assignment of Japanese eel (Anguilla japonica) using a multiple breeding method and microsatellites from eight loci. Five female and 15 male eels were used for mass spawning, and the progeny were collected at the pre-leptocephalus (2days post-hatch [dph]) and the leptocephalus stage (30dph). Almost all progeny (297/301=98.7%) were assigned to a parental couple. Only two female eels (F86 and F88) contributed to the next generation, whereas 13 of 15 males contributed to the next generation. Although there were no statistical differences in the paternity ratio between stages, some males changed the ratio in both females. These data are not directly useful for a breeding program, but are useful to maintain pedigree information, which is essential for implementing a breeding program.

Многолетняя динамика репродуктивных показателей европейского анчоуса Engraulis encrasicolus (L., 1758) и их связь с температурными условиями

Европейский анчоус, или хамса (Engraulis encrasicolus L.), — один из наиболее массовых видов рыб в Азово-Черноморском бассейне. Является основным промысловым объектом: доля его вылова составляет около 80 %. Оценка состояния популяции хамсы и её динамики в условиях климатического потепления — одна из актуальных задач современных исследований. Данная статья посвящена изучению многолетней динамики ряда популяционных репродуктивных показателей хамсы и их связи с температурой воды с целью возможного использования для прогноза состояния популяции при изменении условий среды. В основе работы – полученные в 2000–2015 гг. результаты собственных исследований, выполненных в прибрежной акватории Чёрного моря, прилегающей к юго-западному побережью Крыма (район Севастополя — Балаклавы). Для сбора икры хамсы использовали планктонную сеть Богорова — Расса (БР-80/113) в режиме вертикального лова в слое 0–10 м. Взрослые экземпляры получены из ставных неводов. Проанализированы 702 ихтиопланктонные пробы и 941 экз. нерестовых самок (на стадиях зрелости V, VI–IV и VI–V). Среди популяционных репродуктивных показателей были изучены календарные сроки и продолжительность нерестового периода, интенсивность и эффективность нереста, внутривидовой состав родительского стада. Календарные сроки нереста хамсы в 2000–2014 гг. у юго-западного побережья Крыма варьировали от второй декады мая (ранний нерест) до третьей декады июня (поздний нерест); сроки окончания — от третьей декады августа до третьей декады сентября. Общая продолжительность репродуктивного периода составляла 8–14 недель, средняя — 11 недель. В многолетнем плане установлен сдвиг начала нереста на более ранние календарные сроки. Максимальные (пиковые) среднемесячные значения интенсивности нереста в 2012–2013 гг. варьировали от 33.6 до 78.7 % (среднее 51.2 %). Пик популяционного нереста приходится на июль и август; его повторяемость в июле составила 25.0 %, в августе — 66.7 %. В многолетнем плане установлен сдвиг пика нереста на более ранние сроки: в 2000–2005 гг. повторяемость пика нереста в августе составляла 100 %, в 2007–2013 гг. — только 50 %. Абсолютная численность икры (эффективность нереста) в 2000–2014 гг. изменялась от 1.6 до 29.9 экз.·м-2, составив в среднем 10.3 экз.·м-2. Условно выделены низко-, средне- и высокоурожайные годы с численностью икры менее 10, 10–20 и более 20 экз.·м-2 соответственно и со средней эффективностью нереста 5.1, 14.5 и 25.0 экз.·м-2. Эффективность нереста высокоурожайных лет в 1.7 и 4.9 раза превышает таковую средне- и низкоурожайных лет. Установлен многолетний положительный тренд эффективности нереста. В 2000–2011 гг. произошла перестройка внутривидовой структуры хамсы, которая сопровождалась перераспределением численного соотношения в составе нерестовой части популяции представителей азовского и черноморского подвидов в пользу последнего. До 2004 г. относительная численность черноморской хамсы составляла 33.3 %, после 2004 г. — 76.7 %. Одновременно произошло заметное увеличение её вылова. Коэффициент корреляции между относительной численностью черноморской хамсы и выловом составил 0.92. Календарные сроки начала нереста, его интенсивность и эффективность тесно связаны с температурой воды. Нижней температурной границей массового нереста является 17.5 °С. Область «максимально благоприятной нерестовой температуры» находится выше 23 °С. В её пределах реализуется около 2/3 репродуктивного потенциала популяции.

Selection of a new scallop strain, the Bohai Red, from the hybrid between the bay scallop and the Peruvian scallop

In our previous studies, inter-specific hybrid F1 with significant heterosis in growth was produced by hybridizing the bay scallop, Argopecten irradians irradians with the Peruvian scallop, A. purpuratus. However, due to the hermaphroditic nature of the two Argopecten scallops, it is difficult to produce the hybrid seed at large scales. To efficiently utilize the genetic resources of the two scallops, this study aimed to breed a new scallop strain from the hybrids. The key step in the selection was the breeding of the F1 generation from the hybrid cohort, most of which were both male- and female-sterile. A small cohort of F1 with normal male- and female-fertility was produced through mass spawning of a large cohort of hybrids. The F2–F6 cohorts were reproduced with size- and color-selected brood stocks from the F1–F5 cohort, respectively. The results showed that, compared with the control bay scallop cohorts, the average shell height, average whole body weight and average adductor muscle weight were increased by 15.6%, 37.9% and 40.7% in F1, by 14.7%, 33.9% and 43.6% in F2, by 14.1%, 33.1% and 38.4% in F3, by 11.7%, 38.8% and 49.3% in F4, by 12.2%, 37.9% and 53.8% in F5, by 18.5%, 42.6% and 75% in F6, respectively. After six generations of selection, the median lethal temperature range was expanded from 3.0–29.0°C in F1 to 0°C–29.1°C in F6, suggesting that the selected strain can be reared in most waters of China, especially in Bohai Sea and Yellow Sea. Thus, through continuous selection on size and color, we have obtained a superior strain from the hybrids between the bay scallop and the Peruvian scallop, which is named ‘Bohai Red’.

Mass spawning aggregation of the giant bumphead parrotfish Bolbometopon muricatum

The present study reports a previously undocumented mass spawning aggregation and group spawning phenomena of c. 1200 individual bumphead parrotfish Bolbometopon muricatum in Palau, Micronesia. Although B. muricatum are protected in Palau, it is further recommended that management strategies should consider establishment of no-take zones at B. muricatum spawning aggregations and concomitant sleeping grounds elsewhere.

Mass spawning of crabs: ecological implications in subtropical Australia

We review links between autotrophic production, crab herbivory and estuarine food chains in southeastern Australia, a region where mangrove and saltmarsh co-exist towards mangrove poleward limits. Studies in estuaries and embayments across the region have demonstrated a consistent and important role of crab larvae released in synchronised spawning during the spring tide in supplementing the diet of zooplanktivorous fishes. These numerically dominant fishes have been linked through isotopic studies to commercially important predator species. The role of macrophytic vegetation (mangrove and saltmarsh) in the diet of crabs remains controversial, though isotopic analysis has demonstrated the contribution of the C4 grass Sporobolus virginicus to crabs feeding in saltmarsh. Other dietary sources include microphytic algae, and potentially stranded zooplankton. The link between sediment organic matter, crab and zooplanktivore isotopic composition remained tightly coupled in spite of variation in anthropogenic N between estuaries and the isotopic signature of mangroves. Long-term threats to these trophic linkages include coastal squeeze associated with sea-level rise, and the fragmentation and disconnection of habitats.

Coral spawning and spawn-slick observation in the Philippines

Knowledge on coral reproduction has implications for the restoration and recovery of degraded coral communities. Few studies on coral spawning timing and extent of synchrony have been recorded in the most biodiverse and disturbed coral reef ecosystems of the Coral Triangle. In the present study, the reproductive timing in 2015 and 2016 is reported of an Acropora assemblage in Magsaysay reef, Bolinao-Anda Reef Complex, northwestern Philippines. Fertile colonies were present in February and March, with highest abundance 6 days after full moon. All sampled colonies of five Acropora species were fertile on 12 March 2015 and 73–100% of six Acropora species on 29 February 2016. Other species had fewer mature colonies (40 and 33% respectively), suggesting that these may spawn in other times of the year. Synchrony in gamete development and mass spawning were exhibited among species. At least eight Acropora species were observed spawning between 9 to 11 days after full moon in March of 2015 and 2016. Mass spawning resulted in spawn slicks, which were dispersed by the current generated by the ebbing tides and winds. This observation suggests that the Magsaysay reef may be an important source of larvae that may recruit unto nearby reefs, which could potentially initiate recovery of degraded coral communities.

Assessing the effect of environmental factors on the spawning activity of the sea urchin Strongylocentrotus intermedius through video recording observations

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 588:101-119 (2018) - DOI: https://doi.org/10.3354/meps12436 Assessing the effect of environmental factors on the spawning activity of the sea urchin Strongylocentrotus intermedius through video recording observations Peter M. Zhadan1,*, Marina A. Vaschenko2, Sergey D. Ryazanov1 1V. I. Il’ichev Pacific Oceanological Institute, Far Eastern Branch, Russian Academy of Sciences, 43 Baltiyskaya Street, 690041 Vladivostok, Russia 2National Scientific Center of Marine Biology, A. V. Zhirmunsky Institute of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, 17 Palchevsky Street, 690041 Vladivostok, Russia *Corresponding author: pzhadan@poi.dvo.ru ABSTRACT: We used video recordings of spawning behaviour of the sea urchin Strongylocentrotus intermedius conducted in parallel with an analysis of gonadal state and measurement of environmental variables (tidal level, phytoplankton, temperature, salinity and oxygen concentration) in situ to study the role of environmental factors in triggering sea urchin spawning. The observations were performed during 3 reproductive seasons, each of 2 mo duration, in 2 bays with different levels of phytoplankton (measured as chlorophyll a [chl a]). The only significant positive correlation found was between sea urchin spawning frequency and chl a concentration. Despite a high level of gonad maturity, sea urchin spawning was rarely recorded in the bay with low levels of chl a whereas mass spawning occurred in the bay with higher chl a concentration, with the peak of spawning activity centred around the full moon. Spawning was predominantly nocturnal. Immediately before and during spawning, males actively moved. Females began to spawn only when there were several spawning males nearby. In both sexes, each spawning event included several episodes of gamete release of different duration and with different intervals between them. The same male likely can participate in several spawning events. The following hierarchy of drivers of S. intermedius spawning activity was revealed: (1) increasing the phytoplankton concentration induced active motion and spawning in males, (2) both an elevated phytoplankton level and the presence of sperm stimulated spawning in females and (3) the night time and the new and full lunar phases increased the probability of spawning. KEY WORDS: Broadcast spawning · Echinoderms · Reproductive synchrony · Phytoplankton · Temperature · Circadian rhythm · Lunar cycle Full text in pdf format Supplementary material PreviousNextCite this article as: Zhadan PM, Vaschenko MA, Ryazanov SD (2018) Assessing the effect of environmental factors on the spawning activity of the sea urchin Strongylocentrotus intermedius through video recording observations. Mar Ecol Prog Ser 588:101-119. https://doi.org/10.3354/meps12436 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 588. Online publication date: February 08, 2018 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2018 Inter-Research.

Discovery of methylfarnesoate as the annelid brain hormone reveals an ancient role of sesquiterpenoids in reproduction.

Animals require molecular signals to determine when to divert resources from somatic functions to reproduction. This decision is vital in animals that reproduce in an all-or-nothing mode, such as bristle worms: females committed to reproduction spend roughly half their body mass for yolk and egg production; following mass spawning, the parents die. An enigmatic brain hormone activity suppresses reproduction. We now identify this hormone as the sesquiterpenoid methylfarnesoate. Methylfarnesoate suppresses transcript levels of the yolk precursor Vitellogenin both in cell culture and in vivo, directly inhibiting a central energy-costly step of reproductive maturation. We reveal that contrary to common assumptions, sesquiterpenoids are ancient animal hormones present in marine and terrestrial lophotrochozoans. In turn, insecticides targeting this pathway suppress vitellogenesis in cultured worm cells. These findings challenge current views of animal hormone evolution, and indicate that non-target species and marine ecosystems are susceptible to commonly used insect larvicides.

Genomic Prediction of Resistance to Pasteurellosis in Gilthead Sea Bream (Sparus aurata) Using 2b-RAD Sequencing.

Gilthead sea bream (Sparus aurata) is a species of paramount importance to the Mediterranean aquaculture industry, with an annual production exceeding 140,000 metric tons. Pasteurellosis due to the Gram-negative bacterium Photobacterium damselae subsp. piscicida (Phdp) causes significant mortality, especially during larval and juvenile stages, and poses a serious threat to bream production. Selective breeding for improved resistance to pasteurellosis is a promising avenue for disease control, and the use of genetic markers to predict breeding values can improve the accuracy of selection, and allow accurate calculation of estimated breeding values of nonchallenged animals. In the current study, a population of 825 sea bream juveniles, originating from a factorial cross between 67 broodfish (32 sires, 35 dams), were challenged by 30 min immersion with 1 × 105 CFU virulent Phdp. Mortalities and survivors were recorded and sampled for genotyping by sequencing. The restriction-site associated DNA sequencing approach, 2b-RAD, was used to generate genome-wide single nucleotide polymorphism (SNP) genotypes for all samples. A high-density linkage map containing 12,085 SNPs grouped into 24 linkage groups (consistent with the karyotype) was constructed. The heritability of surviving days (censored data) was 0.22 (95% highest density interval: 0.11–0.36) and 0.28 (95% highest density interval: 0.17–0.4) using the pedigree and the genomic relationship matrix respectively. A genome-wide association study did not reveal individual SNPs significantly associated with resistance at a genome-wide significance level. Genomic prediction approaches were tested to investigate the potential of the SNPs obtained by 2b-RAD for estimating breeding values for resistance. The accuracy of the genomic prediction models (r = 0.38–0.46) outperformed the traditional BLUP approach based on pedigree records (r = 0.30). Overall results suggest that major quantitative trait loci affecting resistance to pasteurellosis were not present in this population, but highlight the effectiveness of 2b-RAD genotyping by sequencing for genomic selection in a mass spawning fish species.

Rapid egg transport following coral mass spawning at Ningaloo Reef, Western Australia

During mass spawning of tropical corals, extremely dense accumulations of eggs develop throughout the water column, the fate of which depends on physical conditions, such as topography, currents, and prevailing winds. We measured egg transport [mainly acroporid corals and the palolo worm, Eunice viridis (Gray, 1847)] during a mass spawning at Ningaloo Reef, Western Australia, in April 2010. We tracked changes in egg and embryo abundance in the lagoon over five consecutive days with plankton tows at the sea surface immediately after spawning and four and 16 hours later, and characterized the flow regime with drifter deployments. Egg dispersal was rapid with a pronounced decrease in concentration within four hours of spawning, from approximately 106 to 101 and 104 m–3 for corals and E. viridis, respectively, on the peak date; few eggs or embryos remained within the lagoon after 16 hrs. Changes in concentration of eggs and embryos along transects inside the lagoon and perpendicular to the reef flat reflected the local hydrodynamics and high flushing rate, providing empirical support for a biophysical model from the same site.

Influence of the hydrological regime in the lower reaches of the Volga delta on natural fish reproduction

This article considers the influence of the hydrological regime in the lower reaches of the Volga delta (based on the example of the Damchiksky site of the Astrakhan Reserve) during high water periods in the low-water year of 2012 and medium-water year of 2013 on the abundance of producers entering for spawning and the density of aggregations of juveniles of roach Rutilus caspicus, vulgaris rudd Scardinius erythrophthalmus, and river perch Perca fluviatilis. It is shown that the fish mass spawning in 2013 was more effective and occurred on floodplain spawning areas with the sequential succession of the investigated species, while the fish spawning was observed in eriks and was less effective in 2012. It was revealed that vulgaris rudd shows the highest adaptation to insufficient watering conditions.

Ocean circulation drives heterogeneous recruitments and connectivity among coral populations on the North West Shelf of Australia

The North West Shelf (NWS) of Australia features extensive and globally significant fringing coral reef ecosystems with high levels of endemism and consequently has received significant conservation efforts in the form of Marine Parks. The shelf circulation on the NWS is dominated by the southwestward-flowing Holloway Current during austral autumn–winter and by the northeastward monsoonal currents during austral summer. Intraseasonal Oscillation and short-term wind variability also influence advection processes on the NWS. These circulation processes are likely to determine demographic inter-dependencies among reef systems in the region, but the extent and spatial variability of the inter-dependence are not well understood. In this study, we used a 3-dimensional, hydrostatic, primitive equations model, to simulate the shelf circulation on the NWS at 1km horizontal resolution during 2004–2009. We then used a particle tracking model based on the shelf circulation model to simulate larval dispersal in a representative coral species, Acropora millepora, among the 3430 coral reefs on the NWS during its autumn mass spawning. Model results predicted that settling larvae typically reach suitable reef within 10days of spawning, with a predominantly southwestward tendency of transport. There was significant spatial heterogeneity in larval settlements and the Dampier Archipelago areas seemed to be more isolated from the rest of the NWS. Year-to-year variations of larval dispersals were sensitive to the seasonal and intraseasonal variations of alongshore winds: mass spawning in late March would expose the Dampier Archipelago area to the Holloway Current onset, resulting in it being an occasional source region of larval supply for the rest of the NWS to the southwest; intraseasonal northeastward wind pulses coinciding with the mass larval spawning would bring larvae from coastal regions to the Dampier Archipelago on rare occasions. By aggregating the reefs into 47 subregions, we estimated that the mean rate of self-seeding within the subregions (as a proportion of total supply) was 22% (range from 99% to <1%). Subregions with high retention (as a proportion of total egg production) were not necessarily those with the highest levels of overall larval settlements. Such high “sink” subregions were also some of the most important “source” subregions. Most of the important source and sink subregions were found to be outside existing marine parks, however, existing marine parks did contain subregions with some of the highest levels of self-seeding and larval retention.

Husbandry and Health Program Survey Synopsis.

ZebrafishVol. 13, No. S1 Survey & SynopsisHusbandry and Health Program Survey SynopsisChristian Lawrence, Judith S. Eisen, and Zoltán M. VargaChristian LawrenceAquatic Resources Program, Boston Children's Hospital, Boston, Massachusetts.Search for more papers by this author, Judith S. EisenInstitute of Neuroscience, University of Oregon, Eugene, Oregon.Search for more papers by this author, and Zoltán M. VargaZebrafish International Resource Center, Institute of Neuroscience, University of Oregon, Eugene, Oregon.Search for more papers by this authorPublished Online:28 Jun 2016https://doi.org/10.1089/zeb.2016.1309AboutSectionsView articleView Full TextPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail View articleFiguresReferencesRelatedDetailsCited byA FELASA Working Group Survey on Fish Species Used for Research, Methods of Euthanasia, Health Monitoring, and Biosecurity in Europe, North America, and Oceania24 August 2022 | Biology, Vol. 11, No. 9A Multi-Site Assessment of Anesthetic Overdose, Hypothermic Shock, and Electrical Stunning as Methods of Euthanasia for Zebrafish (Danio rerio) Embryos and Larvae1 April 2022 | Biology, Vol. 11, No. 4Enrichment for Laboratory Zebrafish—A Review of the Evidence and the Challenges5 March 2021 | Animals, Vol. 11, No. 3Zebrafish: Housing and husbandry recommendations11 September 2019 | Laboratory Animals, Vol. 54, No. 3The Impact of Pseudoloma neurophilia Infection on Body Condition of Zebrafish Justin L. Sanders, Joana F. Monteiro, Sandra Martins, Ana Catarina Certal, and Michael L. Kent27 March 2020 | Zebrafish, Vol. 17, No. 2Health Surveillance ProgramsEvidence of Centrocestus formosanus (Nishigori, 1924) in Zebrafish (Danio rerio) Carmelo Iaria, Sergio Migliore, Daniele Macri, Maurizio Bivona, Fabiano Capparucci, Gabriella Gaglio, and Fabio Marino2 December 2019 | Zebrafish, Vol. 16, No. 6Tools for studying the metabolism of new psychoactive substances for toxicological screening purposes – A comparative study using pooled human liver S9, HepaRG cells, and zebrafish larvaeToxicology Letters, Vol. 305Transmission of Pseudoloma neurophilia in Laboratory Zebrafish (Danio rerio) When Using Mass Spawning Chambers and Recommendations for Chamber Disinfection Samantha M. Peneyra, Jose Cardona-Costa, Julie White, Christopher M. Whipps, Elyn R. Riedel, Neil S. Lipman, and Christine Lieggi1 February 2018 | Zebrafish, Vol. 15, No. 1International survey on the use and welfare of zebrafish Danio rerio in research20 February 2017 | Journal of Fish Biology, Vol. 90, No. 5Systems pharmacology of hepatic metabolism in zebrafish larvaeDrug Discovery Today: Disease Models, Vol. 22 Volume 13Issue S1Jul 2016 InformationCopyright 2016, Mary Ann Liebert, Inc.To cite this article:Christian Lawrence, Judith S. Eisen, and Zoltán M. Varga.Husbandry and Health Program Survey Synopsis.Zebrafish.Jul 2016.S-5-S-7.http://doi.org/10.1089/zeb.2016.1309Published in Volume: 13 Issue S1: June 28, 2016Online Ahead of Print:June 1, 2016PDF download

Coral restoration in Singapore’s sediment-challenged sea

Singapore’s coral reefs have been exposed to five decades of increased sedimentation that reduced underwater visibility from over 10 m in the early 1960s to under 2 m today. The lower depth limit of scleractinian coral growth moved up from 10 m to 6 m, while live coral cover decline is less apparent now than in the early decades of augmented sediment loading. Coral community structure has changed with dominance shifting to more low-light tolerant species such as those of the genera Pectinia and Turbinaria. Reef restoration to increase coral cover of degraded reefs and initiate colonisation of non-reef areas is considered to be viable following observations of predictable mass spawning events, recruitment and vigorous growth, but the techniques employed need to account for the high sediment conditions and destabilised reef substrate. The deployment of fibreglass artificial reef units increased opportunities for coral establishment, and supported at least 106 reef taxa, including 29 scleractinian genera after 10 years. As vital components of restoration, coral nurseries comprising mesh-net platforms raised above the reef floor prevented sediment accumulation and smothering, and enabled the rearing of coral fragments and juveniles with reduced mortality. This included the nurturing of ‘corals of opportunity’ (naturally fragmented pieces of live coral lying on the reef bed as well as recruits settled on loose rubble), which would otherwise be killed by sedimentation. Transplants of massive or encrusting species displayed higher survival over branching ones. Restoration strategies need to be adapted to changed environmental conditions caused by anthropogenic disturbances.

Coral reproduction in Western Australia.

Larval production and recruitment underpin the maintenance of coral populations, but these early life history stages are vulnerable to extreme variation in physical conditions. Environmental managers aim to minimise human impacts during significant periods of larval production and recruitment on reefs, but doing so requires knowledge of the modes and timing of coral reproduction. Most corals are hermaphroditic or gonochoric, with a brooding or broadcast spawning mode of reproduction. Brooding corals are a significant component of some reefs and produce larvae over consecutive months. Broadcast spawning corals are more common and display considerable variation in their patterns of spawning among reefs. Highly synchronous spawning can occur on reefs around Australia, particularly on the Great Barrier Reef. On Australia’s remote north-west coast there have been fewer studies of coral reproduction. The recent industrial expansion into these regions has facilitated research, but the associated data are often contained within confidential reports. Here we combine information in this grey-literature with that available publicly to update our knowledge of coral reproduction in WA, for tens of thousands of corals and hundreds of species from over a dozen reefs spanning 20° of latitude. We identified broad patterns in coral reproduction, but more detailed insights were hindered by biased sampling; most studies focused on species of Acropora sampled over a few months at several reefs. Within the existing data, there was a latitudinal gradient in spawning activity among seasons, with mass spawning during autumn occurring on all reefs (but the temperate south-west). Participation in a smaller, multi-specific spawning during spring decreased from approximately one quarter of corals on the Kimberley Oceanic reefs to little participation at Ningaloo. Within these seasons, spawning was concentrated in March and/or April, and October and/or November, depending on the timing of the full moon. The timing of the full moon determined whether spawning was split over two months, which was common on tropical reefs. There were few data available for non-Acropora corals, which may have different patterns of reproduction. For example, the massive Porites seemed to spawn through spring to autumn on Kimberley Oceanic reefs and during summer in the Pilbara region, where other common corals (e.g. Turbinaria & Pavona) also displayed different patterns of reproduction to the Acropora. The brooding corals (Isopora & Seriatopora) on Kimberley Oceanic reefs appeared to planulate during many months, possibly with peaks from spring to autumn; a similar pattern is likely on other WA reefs. Gaps in knowledge were also due to the difficulty in identifying species and issues with methodology. We briefly discuss some of these issues and suggest an approach to quantifying variation in reproductive output throughout a year.

Coral mass spawning predicted by rapid seasonal rise in ocean temperature.

Coral spawning times have been linked to multiple environmental factors; however, to what extent these factors act as generalized cues across multiple species and large spatial scales is unknown. We used a unique dataset of coral spawning from 34 reefs in the Indian and Pacific Oceans to test if month of spawning and peak spawning month in assemblages of Acropora spp. can be predicted by sea surface temperature (SST), photosynthetically available radiation, wind speed, current speed, rainfall or sunset time. Contrary to the classic view that high mean SST initiates coral spawning, we found rapid increases in SST to be the best predictor in both cases (month of spawning: R(2) = 0.73, peak: R(2) = 0.62). Our findings suggest that a rapid increase in SST provides the dominant proximate cue for coral mass spawning over large geographical scales. We hypothesize that coral spawning is ultimately timed to ensure optimal fertilization success.