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<br /> Fig. 3. Exposure to microplastic particles affects survival,growth,and mean number(±SE)of ingested microplastic particles. (A) Survival curves
<br /> (Kaplan-Meier plot)of 10-day-old P.fluviatilis larvae from the three different microplastic treatments.(B)Standard length and(C)number of microplastic particles 0
<br /> found in stomach contents were also affected by treatment.Juvenile pike[Esox lucius(D)]are a common and natural piscivore that preys on larval perch.Larvae 6
<br /> exposed to the different treatments had consumed varying amounts of microplastic particles:no microplastics(E and F);average amounts of microplasticsco
<br /> (G and H);or high amounts of microplastics(I and J). .-,
<br /> bottom of the aquarium],total distance moved microplastic pollutants.By recording behaviors of vidual survival rates of 2-week-old larvae from ,
<br /> the different treatments when exposed to a nat-hthree different microplastic treat- xP
<br /> (total distance fish swam over the 3 min obser- fish from the pE
<br /> n of time fish were ments before and after the of an alarm ural and common predator on larval perch,Ju- °
<br /> vation period),and the amount injection �
<br /> immobile(s)using standardized protocols(N= cue,we could determine innate fear responses venile pike(Esox lucius,31±1.5 mm total length). -°
<br /> 36)(12,22).We found clear effects of exposure of naive 10-day-old P.fluviatilis(N= 12).We Survival of fish was monitored every 2 to 6 hours 8
<br /> to polystyrene microplastics(average and high found a strong influence of microplastic expo- over a 24-hour period in mesocosms simulating o
<br /> concentrations) on behavior. of 10-day-old fish sure and concentration on the response of fish to natural conditions(N=45 to 47)(19).We found
<br /> larvae[2-factor multivariate analysis of variance olfactory threat cues(2 factor MANOVA:FA291= that microplastic exposure during development �o
<br /> (MANOVA):F6,180=8.47,P<0.00001;Fig.1,A to 6.59,P<0.00001;Fig.2,A to C).Fish reared under influenced survival rates of P.fluviatilis(x22,0,05=
<br /> C].There was a nonsignificant effect of exposure control conditions displayed lowered activity rates 34.02,P< 0.0001).Survival of fish larvae was
<br /> tank on behaviors of individual fish (2-factor (2 factor ANOVA:F4,97=29.72,P<0.0001;Fig.2A), highest and most similar to natural survival rates
<br /> MANOVA; F39,267 = 0.99, P = 0.49). Hatched decreases in distance moved(2-factor ANOVA: at this life stage[e.g.,(20)]when reared under
<br /> larvae that were reared under control conditions F4,97=23.44,P<0.0001;Fig.2B),and a greater control conditions,with 46%still alive after 24 hours
<br /> had higher activity rates(2-factor ANOVA:F2,92= incidence of freezing behavior(e.g.,time immo- (Fig.3A).Fish reared in average microplastic con-
<br /> 7.24;P=0.0012;Fig.1A),swam greater distances bile: 2-factor ANOVA:F4,97=12.94,P< 0.0001; centrations had a lower survival rate,with 66%
<br /> (2-factor ANOVA:F2,92=5.14,P=0.0076;Fig.1B), Fig.2C)in response to conspecific alarm cues. consumed after 24 hours.Larvae reared in high
<br /> and spent less time motionless(2-factor ANOVA: Although there was a tendency of fish reared in microplastic concentrations had the lowest sur-
<br /> F2,92= 28.98,P<0.00001;Fig.1C)compared to the average microplastic concentrations to dis- vival rates,with 100%consumed by pike within
<br /> fish that were reared under microplastic treatment play weaker threat responses compared to con- 24 hours.Observed survival patterns in the cur-
<br /> conditions. trol fish,they still displayed significantly stronger rent study emphasize the importance of behav
<br /> Early life-history stages of many aquatic or- threat responses to chemical alarm cues corn- ioral responses to threat cues,as larval fish failing
<br /> ganisms are inherently vulnerable to predators, pared to the two control cue treatments(hetero- to respond to conspecific alarm cues had threefold
<br /> and an innate ability to detect predators is crit- specific skin extract and water controls;Tukey's (high microplastics=37 out of 45)higher mortality
<br /> ical for survival (10-12). One way naive prey HSD(honest significant difference)test P<0.02; rates compared to control larvae(no microplastics=
<br /> avoid predators is through an innate response to Fig.2,A to C).In contrast,P.,fluviatilis larvae reared 12 out of 47)in the first 10 hours after exposure to
<br /> damage-released chemical alarm cues, and al- in high microplastic concentrations did not exhib- a predator(Fig.3A)(P<0.001).
<br /> though the olfactory sense in larval fish is sen- it an antipredator response when exposed to Two weeks after hatching,total length(mm)
<br /> sitive to changes in habitat composition(22)and threat cues compared to controls(Fig.2,A to C). differed significantly between fish exposed to the
<br /> ocean chemistry(23), it is unknown if olfac- To assess more direct ecological effects of mi- different microplastic concentrations (2-factor
<br /> tory threat responses are affected by exposure to croplastic exposure on fish,we measured indi- ANOVA:F2,46=17.16,P<0.0001;Fig.3B;N=20).
<br /> SCIENCE sciencemag.org 3 JUNE 2016•VOL 352 ISSUE 6290 1215
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