Effects of the marine heatwave MHW and fish predator cues FPC on the survival of males a and females b in F1 Pseudodiaptomus incisus.. Effects of the marine heatwave MHW and fish predato
LITERATURE REVIEW
Marine heatwaves
1.1.1.Definitions and drivers causing marine heatwaves
Among several definitions proposed, marine heatwaves (MHW) are widely described as discrete periods of unusually high temperatures in a certain area which prolong for more than 5 days, as compared to the 90 th percentile of average 30-year sea surface temperatures [41, 59, 73] Besides, MHW were also defined based on higher percentiles to identify more extreme events; fixed limits relating to known species thresholds; or accumulated heat stress.
The development and prolongation of MHW can be related profoundly to the atmospheric state such as high air–sea heat fluxes In addition to this, the possibility of MHW occurrences regionally could be affected increased or decreased by the phase of climate modes of variability [59].
1.1.2.History and prediction of marine heatwaves
The term MHW was first referred to in 2011, when an unprecedented warming event occurred in the West coast of Australia, leading to a massive loss of kelp forest and changes in the associated ecosystems [73] Since then, MHWs have become more common than ever before, increasing in frequency, duration, intensity, and distribution [28, 58] In tropical areas, reports have indicated the appearance of nearly one to three MHW events per year on average, with the duration of 5-10 days
[59] Notably, in the Eastern Pacific, El Niủo-Southern Oscillation events are considered as long-lasting MHWs, which lasted up to 60 days on average In the extratropic regions except the Northeast and Southeast Pacific Ocean having MHW duration of up to 30 days, they are more regularly oscillating between 10 -15 days.
Figure 1.Marine heatwaves (MHW) situation (a) Annually time series of the number of the day that had MHW at any level (yellow), MHW at strong or higher level (orange), and the maximum intensity (blue); (b-d) MHW category (b), duration (c), and maximum difference of sea surface temperature (d) of extreme MHW [73]
In addition to temporal scale, marine heatwaves have also expanded spatially.The Mediterranean Sea heatwave event in 2003 was one of the first documented effects of MHW on the mortality of benthic communities [32] After that, many other locations have also recorded MHW events, notably high ocean temperature during the summer in 2010/2011 along the Western Australian coast [60], OceanHeat Wave in the Northwest Atlantic in 2012 [52], abnormal warm events in the northeastern Pacific Ocean in 2014 [5], and low-latitude MHWs related to the ElNiủo 2015-2016 in the tropical Pacific [73].
Figure 2.Prominent MHW events from 1982 to 2016 The numbers indicate the year when MHW occurred [28]
1.1.2.2 Southeast Asian Sea MHW situation
In the Southeast Asian region, coastal marine organisms are increasingly being exposed to episodes of MHW over the last four decades [24, 84] Based on satellite records from 2016 to 2018 consecutively, unprecedented MHW events occurred in this region in boreal summers Moreover, the following sea surface temperature abnormality was even stronger and spread wider than the previous ones
[30] From 1982 - 2018, the duration of MHWs in the Southeast Asian seas increased from 5 to 9 days per decade [84], and the number of days that the sea surface temperature exceeded 34°C is about 40-60 days per year (Dinh K.V., DoanX.N and Pham Q.H., unpublished data).
Figure 3.Sea surface temperature linear max temperature minus average temperature in Southeast Asian Sea [62].
1.1.3.Ecological impacts of marine heatwave on marine organisms
The effects of MHW on marine ecosystem and biota are becoming more severe under ongoing climate change Species in the past have already acclimated or adapted in order to deal with global warming However, in light of more extreme events as well as degraded habitats, which have been happening at a rapid rate, modern species have to face with unprecedented challenges [57] In the last decade, MHWs have emerged as a major driver in reshaping marine biodiversity, causing the topicalization of temperate coastal ecosystems, mass coral bleaching, and mass mortality of coastal invertebrates worldwide [31, 32, 42, 72].
Although impacts of MHW vary among species and populations, there are four main types of change in species’ features due to warming [65, 73] The first is the change in the distribution of organisms towards higher latitudes Species with narrow thermal niches are replaced by their wider counterparts and tend to move poleward which is suitable to their metabolic temperature tolerance [65] Secondly, species may shift their timing of life cycle events (phenology) to avoid fitness- reducing high temperature periods For example, adult Atlantic salmon in the lower Connecticut and Long Island Sound have migrated 9 to 21 days sooner as compared to 1977 due to extreme warming [45] Thirdly, species observed adjustments in both morphological, such as size reduction, or behavioral under warming condition For example, Leung et al have demonstrated this by noticing the reduction and complete disappearance of marine gastropods on rock surfaces in increasing temperature conditions [50] These almost universal responses have been found in over 80% of tested organisms, from bacteria to fish [11] And the last of which is modification in the cellular or/and genetic materials.
Recent studies have showed that tropical coastal organisms, such as copepods or fish, in the South China Sea are especially vulnerable to extreme temperatures For example, the grazing rate, and respiration, development and reproduction of the tropical copepod Pseudodiaptomus annandalei were negatively affected at temperatures beyond 32 °C [1, 17, 18, 49] Furthermore, ambient water temperature in coastal regions of the Southeast Asian Sea occasionally goes higher than their upper thermal optimum (Appendix S1 – in situ temperature variation – [17]), and episodes of MHW often last beyond one generation of tropical invertebrates However, studies were mostly limited to one exposed generation, which remains an unanswered question of how transgenerational plasticity to MHWs might ameliorate the effects of warming on offspring generation (see, e.g., in coral fish, [20]).
Fish predator cues
Fish predator cues (FPC), also called kairomones, is a chemical signaling secreted by the predator itself when capturing their preys The prey can use it to detect and hide from their predators [8] There is still little knowledge on the exact chemical formulation and the origin of FPC, also some have theorised that FPC secretion is controlled by the bile or they could be made up of selected components in the bile [63].
1.2.2.The role of predator cues to marine species
Predator–prey interactions play a fundamental role in shaping ecosystems, populations of most taxa, and community dynamics [37] In aquatic ecosystems, organisms are surrounded by chemical signaling including those secreted from their predators, which can provide valuable information for the prey Predator cues maybe useless for immediate predation risk since the predator may move far away. However, as its scent is still around, nonlethal (non-consumptive) predation risk could have stronger effects in shaping the physiology, morphology, behaviors (e g. migration), and life history (e g age at first reproduction, number of offspring) of the prey than direct consumption For example, Pleurobrachia pileus changes their vertical distribution as well as move away from the sediment in the presence of predation risk in water [23].
For copepods, non-consumptive predation risk could influence their growth, feeding, reproduction, and life history strategies [4, 38, 47] For example, the presence of fish predator cues increases the growth rate of Temora longicornis[4]. However, the presence of chemical predator cues impairs the reproduction of estuarine copepods, for example, by reducing the proportion of egg-carrying females Eurytemora affinis [38], and for Calanus finmarchicus, they triggered the reduced size and lipid fullness, which halving the growth and development rates
[47] Moreover, compared to land and air environment, the diffusive ability of molecules in water is much slower, which could lead to them last more than one generation of copepod species [80].
Transgenerational plasticity and parental effects
Transgenerational plasticity (TGP) is a term coined as the conditions experienced in the offspring’s generation can interact with those in their parental generation to influence their performances through non-genetic mechanisms [21]. TGP generally occurs through epigenetic changes, habitat selection, or niche construction [19] In particular, epigenetic changes such as the methylation of genes encoding oxygen consumption, mitochondrial activity, and energy homeostasis play crucial functions in restoring the performance of stress-exposed organisms across generations [66].
Besides TGP, the parental effect is another non-genetic transgenerational effect Sperms, eggs, or embryos received nutrients from their modified parents, leading to changes in offspring performance [40] Alternatively, genetic selection may occur through stressor-induced mortality [46] or selection in favor of higher hatching success [10], which removes the most sensitive genotypes or increases the tolerant genotypes in the population, and may contribute to increased fitness of the offspring generation.
1.3.2.Roles of TGP under global climate changes
Recent advancements in eco-evolutionary studies on adaptations of organisms to warming, ocean acidification, and contaminants have further explored the critical role of transgenerational plasticity (TGP) [20, 21, 26, 34, 55, 75] For example, the aerobic scope of the tropical coral damselfish A polyacanthus was reduced by 15-30% when exposed to acute elevated temperatures of +1.5°C and +3°C, but the index in the offspring’s generation, in which the temperature was similar, showed full recovery [20].
TGP is especially crucial for organisms to cope with new, predictable but fast-changing, and short-term environment changes across generations [21] It could be a mechanism for the resistance of marine organisms to MHW as the duration of an MHW often lasts longer than one generation for nearly all tropical zooplankton species (5-14 days) but not long enough for directional evolutionary adaptation, as occurs in response to seasonal changes in water temperature [67] or long-term warming [10, 14].
Multi-stressors effects on organisms
1.4.1 The importance of studying the effect of the combined many stressors
In reality, each species is not solely influenced by one single stressor, but by many simultaneously There are three types of the interactive effects of multiple stressors on the organisms: additive (the combined effect of two or more stressors on an ecological response is the cumulative value of individual stressors), antagonistic (the combined effect of two or more stressors on an ecological response is milder than those of individual stressors), or synergistic (the combined effect of two or more stressors on an ecological response is greater than those of individual stressors) [9, 25] In fact, these antagonistic and synergistic effects seem common in nature Studying the interactions of many stressors on the organism will give us a more multi-dimensional and realistic perspective on how a population of a species handles its environmental elements.
1.4.2.Previous studies on the effect of marine heatwave and predator cues on marine species
Previous studies pointed out the importance of biotic-interaction presence to assess the effects of warming events on a species, such as their abundance and distribution, behavior, life–history traits, and morphology In some cases, the adaptation can be transgenerational [36, 52, 70, 78] Our previous study shows that FPC induced a higher individual performance of the calanoid copepod
Pseudodiaptomus incisusunder control temperature, but it magnified the deleterious impacts of MHW on grazing and reproductive success [78].
Understanding whether copepods are resilient or vulnerable to MHWs in the context of predation stress is important, given that they are a key pathway for the transfer of energy and resources from photosynthesizing organisms to higher trophic levels, and ultimately, the productivity of the coastal ecosystems [7].However, the combined effect of heatwaves and non-consumptive predation risk on prey species across generations is still a major knowledge gap in the current ecological research Investigations of the transgenerational effect of MHWs in an ecologically relevant context, such as the presence of fish predator cues (FPC) on key zooplankton species is relevant and timely with increasing frequency, severity and duration of MHWs and the intense predation stress of tropical coastal environments.
Biological characteristics of copepods
Copepod is a small group of the subphylum Crustacea, belonging to the phylum Arthropoda Copepods are found in nearly every aquatic habitat, from freshwater to marine [6, 44] They are a dominant group of mesozooplankton in coastal mangroves and lagoons [79].
Copepods are the major link between primary producers and higher trophic consumers Copepods are a key food, contributing up to 97-98% of the diets of many larval and juvenile fish in their natural habitats such as anchovy, barramundi, and mackerel Thus, any changes in this group can take a heavy toll on the whole ecosystem [12, 13, 80] Besides, copepods also contribute to the carbon, nitrogen and other element fluxes in the ecosystems through excretion and faecal pellet production [22, 27] For example, in the Westerschelde estuary, 6% of total consumed carbon in the brackish zone passes through the copepod-containing food web [22].
In the experiment, due to their small size, short life cycle, wide distribution, and high cultivated ability, copepods are considered ideal science research objects
[48] Moreover, because of their sensitivity to temperature, they are most suitable for assessing the impacts of marine heatwaves on marine species.
P incisus is found widely in the Indo–West Pacific Ocean [83] In Vietnam, they distribute locally as a dominant group in lagoons along the central coast [79].
Figure 4 P incisusa) nauplii; b) copepodite; c-d) mature female without (panel c) and with (panel d) egg sacs; e) mature male [Vu Ngoc Anh, 2020]
According to Thuy et al (2020) [56], the development of P incisus encompasses 12 stages: 6 nauplii, 5 copepodite and adults The nauplii stage consists of five cycles of moulting In this stage, the body length normally ranges between 70 to 110 àm with a strawberry-like shape This stage often lasts for 2 to 3 days before moving on to the copepodite stage of the life cycle P incisus in the copepodite stage have a similar body shape to those of the adult, but are smaller and have an incomplete body segmentation They need to moult five more times in 6 to
Adult females (♀): prosomal length 680–750 àm long, egg-shaped Female adults have four abdominal segments and four tail segments.
Adult males (♂): usually 100–150 àm smaller than female individual Males have one more tail segment.
The fertilization of P incisus usually lasts for 48 h Eggs are covered in egg sacs and an egg sac can contain from about 20 to 40 eggs in normal conditions.After fertilization, eggs are kept in an egg sac at the first segment of the female tail.The duration from successful fertilization to hatching often lasts 72 h After hatching for around 24 h, the female and the male will continue to fertilize In some unfavourable conditions such as extreme temperature or fluctuating salinity, the copepod will delay reproductivity to protect the embryo inside the egg sac against these adverse conditions.
OBJECTIVES, HYPOTHESES AND METHODS
Objectives of the study
The combined effects of MHW and non-consumptive predation risk on prey species across generations remain a major knowledge gap in current ecological research Therefore, in this study, we unravel the aforementioned question by assessing the direct effect during the exposure [15], together with the effects of parental exposure, TGP (parental and offspring exposure) to MHW, FPC, and their interactions on the growth and development of the copepods Pseudodiaptomus incisus through survival rates of both sexes, clutch sizes, percentage of female with hatched eggs, the number of hatched nauplii per clutch, cumulative nauplii and faecal pellets in five days The experiment was conducted in a full orthogonal manner with 4 treatments in F1 and 16 treatments in F2 generation (Figure 5).
Figure 5.The schematic overview of the transgenerational experiment for the direct and transgenerational MHW and FPC effects onPseudodiaptomus incisus
Hypotheses
We tested the susceptibility of P incisus to MHW and/or FPC in two generations by following eight hypotheses:
H1: MHW reduces the performance of P incisus due to energetic constraints under extreme warming [78].
H2: FPC increases the performance of P incisus as a general antipredator response [4, 78].
H3: FPC-induced increase in performance of P incisus is not sustained under MHW due to the energetic constraints [78].
H4: Parental exposure to MHW reduces offspring performance in the control temperature due to poor maternal provisioning [77].
H5: Parental exposure to FPC increases offspring performance in the absence of FPC [82].
H6: TGP to MHW ameliorates the MHW effect on P incisusoffspring [20].
H7: TGP to FPC decreases the P incisus offspring performance toward antipredator responses [69].
H8: The magnitude of TGP to MHW is altered by TGP to FPC, and vice versa.
This is predicted based on the different types of responses of P incisus toTGP to MHW and FPC.
Implementation time and study site
The implementation of the study was divided into two phases
Wet laboratory, Cam Ranh Centre for Tropical Marine Research and
Aquaculture, Nha Trang University, Khanh Hoa province.
-Data analysing and report writing:
Department of Ecology, Faculty of Biology, VNU University of Sciences, Hanoi
Materials and instruments
Adult copepod Pseudodiaptomus incisus were collected from a coastal pond in Cam Ranh Bay, in July 2020 as F0 generation, using a zooplankton net (mesh size = 200 μm) The coordinates of the pond are (11.82397°N, 109.1233°E, Fig 6). During the collection, the pond water salinity and temperature were 27 - 28°C and
Figure 6.Sample collecting site map [Source: Google maps]
Sea water was pumped from Nha Trang bay into sedimentation ponds before being transported to 3000-m 3 ponds then being filtered with 200 m 3 sand and going through a filtering column with a pore size of 0.5 àm The salinity of the water source was adjusted with fresh water to maintain at 30 PSU Copepods then were transferred to the Copepod Laboratory at Cam Ranh Centre for Tropical Marine
Algae Isochrysis galbana was bought from the algae laboratory of Toan Hung company (No 94, Hai Thang Tu Road, Vinh Hai district, Nha Trang city, Khanh Hoa province) Then algae were kept in 5–L bottles with sterilized water of
25 ppt salinity and f/2 media under a controlled temperature of 24 °C [18] The cultivating condition was kept stable at 24L:0D photoperiod and dissolved oxygen of 5 – 6 mg L -1 by gentle aeration The cultures were supplied with CO2 in order to keep algae in suspension.
When the density of algae in cultures reached to 5-7 × 10 6 cells.mL -1 , approximately 2500 mL of cultures was taken out and replaced with sterilized water of 25 ppt salinity and f/2 media Algae was diluted with seawater to the designated concentration before feeding copepods.
Barramundi (Lates calcarifer) larvae (15 individuals) were reared in 1–L bottle for three days The total length of barramundi is 14 ± 1 mm A previous study has shown that barramundi larvae and juveniles with a total length of 4 – 20 mm virtually prey upon copepods [11] Fish larvae were fed with P incisus After three days, fish larvae were removed, the remaining water containing fish predator cues was collected, divided into aliquots and frozen at -20 °C FPC was thawed before used in the experiment The effect of FPC still remains after being frozen [53].
Four 200 mL water tanks were set with heaters to regulate the temperature in each treatment Water in water tanks was mixed up by a pump in order to distribute the temperature equally.
During the experiment, we used a stereo-microscope (SZ51, Olympus, Japan)
Figure 7.Stereo-microscope SZ51, by Olympus, Japan.
Experimental methods
F0 adult copepods were acclimated in water baths to the temperature of 30°C or 34°C for three days 30°C was chosen as the control temperature since it is the mean sea surface temperature in the southern Vietnam coastal sea (see Appendix S1, [17]) The MHW condition was manipulated at a temperature of 4°C since it is about ~2°C higher than the 90% temperature variations measured in the Cam Ranh Bay (Doan X.N., Pham, Q.H and Dinh K.V., unpublished data) Adult males and females were sorted and then divided into 5-L bottles, approximately 1200 individuals per bottle The temperature was gently increased by 1°C every 12 hours until reaching the experimental temperatures During the acclimation, the salinity, light: dark cycle, and dissolved oxygen concentration were kept at 30 PSU, 12L:12D, and >5 mg L -1 by aerations, respectively (see also [78]) F0 P incicus were fed two times a day with Isochrysis galbanaat 30,000-33,000 cell L -1 (~800 –
2.5.2 Experimental design and set up
To start the experiment, acclimatized F0 female P incisus carrying egg sacs(prosomal length = 797.43 ± 2.17 àm, clutch size = 16 ± 2 eggs) were assigned to1.2-L plastic bottles (15 females each bottle) and fed withI galbana for incubation.
F1 nauplii (180 - 240 individuals per bottle) were collected for the main experiment. There are 4 treatments in F1 generation: 2 temperatures (30°C or 34°C) × 2 FPC (absence or presence) × 10 replicates (Fig 5, Fig 8) FPC solution or filtered seawater (1 ml) was added to each experimental bottle The rearing medium and FPC and algae were renewed daily to minimize the change in the FPC concentration and the indirect effect of MHW on the algal quality [78].
To generate F2 generation, once F1 developed into adults, 20 F1 females carrying egg sacs in each of 10 bottles of each treatment (200 individuals per F1 treatment) were collected and transferred into 20 bottles (10 F1 females per bottle) and incubated for 30 h F2 offspring in every F1 treatment were divided into four groups, corresponding to four experimental conditions 30°C – no FPC, 30°C – FPC, 34°C - no FPC and 34°C - FPC, resulting in 16 treatments (Fig 5, Fig 8).
Figure 8.The schematic of experimental design testing the direct and transgenerational MHW and FPC effects onPseudodiaptomus incisus.
In both generations, we analysed clutch size (from fixed females carrying an egg sac), hatching success, the survival of males and females, cumulative nauplii and faecal pellets over five days In addition to the aforementioned parameters, to fully assess the growth ofP incisus, we are currently measuring size at the maturity of both male and female copepods.
Clutch size of a female copepod was defined as the number of eggs in egg sacs To measure clutch size, 10 random female copepods carrying egg sacs from each bottle were fixed with formaldehyde (4%) The egg sacs then were opened, using a needle, and counted under a stereo-microscope (SZ51, Olympus, Japan).
12 female P incisus carrying egg sacs from each bottle were assigned individually into a 12-well plate, filled with 3m L of seawater with or without predator cues that were prepared in advance They were fed withI galbana, 30,000
– 33,000 cells L -1 (800 - 850 àg C L -1 ) Well-plates were placed in the water baths at the corresponding temperature of 30 or 34°C for 30 hours Subsequently, plates were taken out and females with newly hatched nauplii were immediately fixed with Lugol 4% and quantified using a stereo-microscope (SZ51, Olympus, Japan). The hatching success of copepods were accessed through the percentage of females with hatched eggs and the number of hatched nauplii per clutch.
The percentage of females with hatched eggs was then calculated as below:
Hatching success (%) The survival, cumulative nauplii, and faecal pellets in five days
To evaluate the reproductive output and the grazing rate of P incisus, we quantified the cumulative nauplii and faecal pellets in five days Ten adults of both sexes were transferred to a separated 1-L bottle (10 replicates per treatment) Bottles pellets Alive adults were returned to the bottle while the dead ones were removed and noted for the survival report The content containing nauplii and faecal pellets was transferred to a petri dish, fixed with Lugol (4%) The number of nauplii and feacal pellets was counted using a stereo-microscope (SZ51, Olympus, Japan) In calanoid copepods, the feacal pellets were used as the index of the ingestion [2], which typically has a positive correlation with egg production [3].
Size at maturity of copepods
The prosomal length (àm) was defined as the distance from the tip of the cephalosome to the end of the metasome.10 individuals per sex were collected randomly from each experimental unit After being fixed with formaldehyde (final concentration of approximately 4%), the prosomal length of adult copepods was measured by using a stereo-microscope (SZ51, Olympus, Japan) We have now obtained initial results in F1 generation, which will presented in the section 3.2. Preliminary investigative results: Effects of MHW, FPC, and their interactions on the size at maturity ofP incisus.
The data were analyzed using the R program (version 4.1.3 released on 2022-03-10) MHW and FPC (F1 generation) and F1-MHW, F1-FPC, F2-MHW and F2-FPC (F2 generation) were fixed covariates in the statistical models Survival of females and males, as the response variable, was defined as continuous proportions ranging from 0 to 1 as quasibinomial distribution using the GeneralizedLinear Models (GLM) with the F-test Hatching success was incorporated as a binomial distribution in the GLM with the Chi-test A Poisson GLM with a log link function was used to model the clutch size and hatched nauplii per clutch as a function of the fixed covariates We modeled cumulative nauplii per female and cumulative faecal pellets per individual, which were average values of the observations on each replicate, as a quasipoisson distribution using GLM with F- test The interaction terms in the models were MHW x FPC (F1 generation) and the two-way, three-way and four-way interactions of F1-MHW, F1-FPC, F2-MHW andF2-FPC (F2 generation).
The fitted models of binomial and Poisson distributions were checked for overdispersion We refitted the models having overdispersion by applying the following solutions: (i) removing outliers of the response variables, (ii) defining the response variables as quasi- distribution in the models, (iii) including random factors using Generalized Linear Mixed-Effects Models (GLMER, package lme4 version 1.1-29), and/or (iv) changing to a negative binomial model using NegativeBinomial Generalized Linear Model (GLM.NB, package MASS version 7.3-57).The possible models were then validated using (i) Akaike information criterion(AIC) if available, (ii) plotting and assessing residuals versus fitted values, (iii) evaluating predicted versus actual values of response variables, (iv) checking the normal distribution of the residuals The best-fit model is the one that has the smallest AIC, minor errors in the predicted values and more normally distributed residuals.
RESULTS AND DISCUSSION
Results
3.1.1.Effects of MHW, FPC, and their interactions on F1 generation of P incisus
Exposure to MHW reduced survival of both males and females by 17-18% (MHW, Table 1, Fig 9, in agreement with H1) The lethal effect of MHW was independent of FPC exposure, indicated by an insignificant MHW × FPC interaction (Table 1, Fig 9, in contrast with H3).
Figure 9.Effects of the marine heatwave (MHW) and fish predator cues (FPC) on the survival of males (a) and females (b) in F1Pseudodiaptomus incisus Data are visualized as mean ± SEs.
The reproductive success and grazing of P incisus were overall affected negatively by MHW (MHW, Table 1, Fig 10, Fig 11, in agreement with H1) The hatched nauplii per clutch dropped by 62% at 34°C (Table 1, Fig 10c) The cumulative nauplii and faecal pellets were 27% and 28% lower in MHW than in the control temperature (Table 1, Fig 11) The FPC effect on the percentage of females with hatched eggs was insignificant (Table 1, Fig 10b, in contrast with H2) The number of hatched nauplii per clutch, and cumulative faecal pellets of P incicus increased in the presence of FPC (FPC, Table 1, Fig 10c, Fig 11, in agreement with H2), but the FPC effect on the latter was several times higher in the control temperature than in MHW (MHW × FPC, Table 1, Fig 11b, in agreement with H3).
Figure 10.Effects of the marine heatwave (MHW) and fish predator cues (FPC) on the number of eggs per clutch (a), percentage of females produced hatched eggs (b), hatched nauplii hatched from a clutch (c) of F1Pseudodiaptomus incisus Data are visualized as mean ± SEs.
Table 1 The results of the statistical analyses testing effects of marine heatwave (MHW) and fish predator cues (FPC) on survival, reproductive parameters and cumulative faecal pellets of F1 Pseudodiaptomus incisus Significant P values are signed with *.
Response variables Models Factors Df1 Df2 F P
Female survival GLM - quasibinomial MHW 1 38 33.80