Abstract Investigating the effects of underwater noise on aquatic animals is a research field that is receiving rapidly increasing attention. Despite this, surprisingly few studies have addressed the potential impacts of noise in a marine animal husbandry setting. In this regard, the behaviour of fish in public aquariums can be used as an indicator of well-being, and noise is known to cause behavioural changes. This case study investigates the behaviour of cod (Gadus morhua) and saithe (Pollachius virens) in a large public aquarium when exposed to increased noise levels originating from an aquarium renovation carried out by construction divers. Swimming behaviour, group formation and vertical distribution, along with yawning and scratching frequencies of the fish, were analysed from video recordings made before, during and after the exposure to increased noise levels. The same parameters were also analysed to evaluate potential effects of the presence of divers when not making renovation noise, compared to fish behaviour prior to the renovation. There was a slight change in the depth distribution of both species and a decrease in the number of scratches in cod due to the presence of divers that were not making renovation noise. In the presence of construction noises in the tank, however, both cod and saithe showed a wider array of behavioural changes, including increased swimming speed, changes in depth distribution and increased yawning frequencies. The results from this case study demonstrate that an underwater renovation with increased noise levels impacts fish behaviour and suggests that underwater noise should be considered during the management of aquatic environments, including public aquaria.

The Göta Canal was opened in 1832 and connects the Baltic and the Atlantic Sea via the large lakes Vänern and Vättern in south Sweden. Originally used for commercial transport, the canal is today one of the most popular tourist attractions in Sweden with canal cruises, pleasure boating and canoeing. Inventories in 2013 showed that Dreissena mussels recently have invaded lakes, streams and canals in the Motala River drainage basin, i.e. the eastern part of the Göta Canal. According to interviews with local people the mussels may have been there since 2012. During the late summer in 2013 and in 2014 we monitored mussels by scuba diving and we sampled planktonic larval populations in locks and the canal. Dreissena has not dispersed to the western part of the canal system, i.e. west of lake Vättern, where most lakes are oligotrophic with low Ca- andMg-levels. In the eastern part, where several lakes are eutrophic and Ca- and Mg-levels higher, populations have increased very fast. The inventories showed local densities of 10 000 adults m^-2 in some eutrophic lakes and larval densities of up to 70 individuals L^-1 in the canal water. In Europe, the large range expansion of Dreissena occurred during the late 19th and early 20th century. Why have they dispersed so late into the Göta Canal, i.e. some 170 years after the canal was constructed and some 80 years after they had dispersed to other lakes in Swedennorth of Göta Canal? We can not dismiss dispersal as a a limiting factor but given the historically sustained boat traffic in the region it seems likely that ecological factors may have been important. Freshwaters in Scandinavia are usually low in Ca and Mg and many lakes are characterized by oligotrophic conditions poor in food for filter-feeding Dreissena. In the Göta Canal, changes in biological factors affecting relationships between Dreissena and the regional biota needs to be studied, however. Although we can not explain the delayed invasion we conclude that Dreissena is now established in one of the largest canal system in northern Europe.

Anthropogenic noise is a global pollutant but its potential impacts on early life-stages in fishes are largely unknown. Here, using controlled laboratory experiments, we tested for impacts of continuous or intermittent exposure to low-frequency broadband noise on early life-stages of the common goby (Pomatoschistus microps), a marine fish with exclusive paternal care. Neither continuous nor intermittent noise exposure had an effect on filial cannibalism, showing that males were capable and willing to care for their broods. However, broods reared in continuous noise covered a smaller area and contained fewer eggs than control broods. Moreover, although developmental rate was the same in all treatments, larvae reared by males in continuous noise had, on average, a smaller yolk sac at hatching than those reared in the intermittent noise and control treatments, while larvae body length did not differ. Thus, it appears that the increased consumption of the yolk sac reserve was not utilised for increased growth. This suggests that exposure to noise in early life-stages affects fitness-related traits of surviving offspring, given the crucial importance of the yolk sac reserve during the early life of pelagic larvae. More broadly, our findings highlight the wide-ranging impacts of anthropogenic noise on aquatic wildlife living in an increasingly noisy world.

Anthropogenic underwater noise is a global pollutant of increasing concern and its effect on marine organisms is largely unknown. Importantly, direct assessments of fitness consequences are lacking especially in fish. The effect of noise pattern with continuous or intermittent noise are poorly understood and the few existing studies investigating the effect highlight contradictory responses in fish. Working in aquaria, we experimentally tested the impact of broadband noise exposure (similar frequency range as anthropogenic boat noise; added either continuously or intermittently) on the behaviour and reproductive success, assessed by the number of obtained eggs, of the common goby (Pomatoschistus microps), a vocal fish with exclusive paternal care.  The continuous noise treatment had the most detrimental effect by reducing spawning probability and females took longer to spawn under continuous noise. Males exposed to continuous noise got significantly fewer egg clutches (4 compared to 11 and 15 in the intermittent noise and silence treatments).  Clutch area did not differ among treatments but clutches in the intermittent and continuous noise treatment had significantly more eggs per cm2. In addition, eggs in the control tanks hatched earlier than in the intermittent and noisy treatments. Larvae reared in continuous noise treatment were larger and had a smaller yolk-sac at hatching than larvae in the intermittent noise treatment and the control. Taken together, we show that noise, particularly a continuous noise exposure, negatively affects reproductive success and early life survival in fish larvae.

På senare år har allt fler främmande, invasiva arter börjat breda ut sig i våra sötvatten. En främmande art är en organism som har spridits utanför sitt naturliga utbredningsområde med människans hjälp. Detta kan ha skett avsiktligt eller av misstag. En del av dessa nya arter ställer till problem, andra gör det inte. Här beskrivs övervakningen av några invasiva arter samt hur man kan arbeta för att begränsa dem. Ullhandskrabba, vandrarmussla och sjögull kommer av allt att döma att öka sin utbredning i Sverige de närmaste åren. Det finns idag ett stort antal främmande arter rapporterade från svenska sötvatten och i vår närhet finns ett femtiotal nya arter som kan tänkas etablera sig här. Alla dessa arter kommer inte nödvändigtvis att skapa problem men kunskap om deras biologi och observationer från allmänheten kommer att betyda mycket även i det framtida övervakningsarbetet.

Species invasions are a global problem of increasing concern, especially in highly connected aquatic environments. Despite this, salinity conditions can pose physiological barriers to their spread, and understanding them is important for management. In Scandinavia's largest cargo port, the invasive round goby (Neogobius melanostomus) is established across a steep salinity gradient. We used 12,937 SNPs to identify the genetic origin and diversity of three sites along the salinity gradient and round goby from western, central and northern Baltic Sea, as well as north European rivers. Fish from two sites from the extreme ends of the gradient were also acclimated to freshwater and seawater, and tested for respiratory and osmoregulatory physiology. Fish from the high-salinity environment in the outer port showed higher genetic diversity, and closer relatedness to the other regions, compared to fish from lower salinity upstream the river. Fish from the high-salinity site also had higher maximum metabolic rate, fewer blood cells and lower blood Ca2+. Despite these genotypic and phenotypic differences, salinity acclimation affected fish from both sites in the same way: seawater increased the blood osmolality and Na+ levels, and freshwater increased the levels of the stress hormone cortisol. Our results show genotypic and phenotypic differences over short spatial scales across this steep salinity gradient. These patterns of the physiologically robust round goby are likely driven by multiple introductions into the high-salinity site, and a process of sorting, likely based on behaviour or selection, along the gradient. This euryhaline fish risks spreading from this area, and seascape genomics and phenotypic characterization can inform management strategies even within an area as small as a coastal harbour inlet. 

In species with alternative reproductive tactics (ART), parasitically spawning males have larger testes and greater sperm numbers as an evolved response to a higher degree of sperm competition. But do they also have higher sperm performance? We used sand gobies to test if it differs between breeding-coloured and sneaker-morph males. We compared sperm motility, velocity, longevity, morphometrics and gene expression of testes between the two morphs. We found 109 transcripts differentially expressed between the morphs. Notably, several mucin genes were upregulated in breeding-coloured males and two ATP-related genes were upregulated in sneaker-morph males. There was partial evidence of higher sperm velocity in sneaker-morph males, but no difference in sperm motility. Sand gobies have remarkably long-lived sperm, with almost no decline in motility and velocity over 22 hours, but again, this was equally true for both morphs. Sperm length did not differ between morphs and did not correlate with sperm velocity for either morph. Thus, other than a clear difference in testes gene expression, we found only modest differences between the two male morphs, confirming previous findings that increased sperm performance as an adaptation to sperm competition does not appear to be a primary target of evolution.

Studies of colonization of new habitats that appear from rapidly changing environments are interesting and highly relevant to our understanding of divergence and speciation. Here, we analyse phenotypic and genetic variation involved in the successful establishment of a marine fish (sand goby, Pomatoschistus minutus) over a steep salinity drop from 35 PSU in the North Sea (NE Atlantic) to two PSU in the inner parts of the post-glacial Baltic Sea. We first show that populations are adapted to local salinity in a key reproductive trait, the proportion of motile sperm. Thereafter, we show that genome variation at 22,190 single nucleotide polymorphisms (SNPs) shows strong differentiation among populations along the gradient. Sequences containing outlier SNPs and transcriptome sequences, mapped to a draft genome, reveal associations with genes with relevant functions for adaptation in this environment but without overall evidence of functional enrichment. The many contigs involved suggest polygenic differentiation. We trace the origin of this differentiation using demographic modelling and find the most likely scenario is that at least part of the genetic differentiation is older than the Baltic Sea and is a result of isolation of two lineages prior to the current contact over the North Sea–Baltic Sea transition zone.

In externally fertilizing species, the gametes of both males and females are exposed to the influences of the environment into which they are released. Sperm are sensitive to abiotic factors such as salinity, but they are also affected by biotic factors such as sperm competition. In this study, the authors compared the performance of sperm of three goby species, the painted goby, Pomatoschistus pictus, the two-spotted goby, Pomatoschistus flavescens, and the sand goby, Pomatoschistus minutus. These species differ in their distributions, with painted goby having the narrowest salinity range and sand goby the widest. Moreover, data from paternity show that the two-spotted goby experiences the least sperm competition, whereas in the sand goby sperm competition is ubiquitous. The authors took sperm samples from dissected males and exposed them to high salinity water (31 PSU) representing the North Sea and low salinity water (6 PSU) representing the brackish Baltic Sea Proper. They then used computer-assisted sperm analysis to measure the proportion of motile sperm and sperm swimming speed 10 min and 20 h after sperm activation. The authors found that sperm performance depended on salinity, but there seemed to be no relationship to the species' geographical distribution in relation to salinity range. The species differed in the proportion of motile sperm, but there was no significant decrease in sperm motility during 20 h. The sand goby was the only species with motile sperm after 72 h.

Some Bosmina water flea species develop morphological antipredatory defenses, such as long antennules and a high carapace, but in Bosmina (Eubosmina) coregoni gibbera these traits are larger and more variable in females than in males. Here we propose that this sexual dimorphism derives from differential costs of hydrodynamic drag and selection for mobility in males. We tested this hypothesis by estimating drag of several Bosmina morphologies by using scale models sinking in glycerin of different concentrations and viscosities. Body forms included males, sexual and asexual females of B. c. gibbera, and males and asexual females of Bosmina (Eubosmina) longispina, a taxon with less variable body shape. For a given body length or body volume, male models had lower drag than models of sexual and asexual females, suggesting that males can swim 14–28% faster with the same energy consumption. Consistent with this conclusion, video recordings showed that males of B. c. gibbera advanced 55–73% farther than females in each swimming stroke. We conclude that hydrodynamic drag may have significant implications for swimming and evolution of sexual dimorphism in water fleas, and we suggest that males lack the defensive structures of females of B. c. gibbera (e.g., high carapaces) because competition over mates favors low drag.

Biosolids are the biological organic matter extracted from various treatment processes of wastewater which are considered as a rich source of energy and nutrients. The most commonly used method for the disposal of biosolids is landfilling. But this causes the loss of valuable nutrients and creates environmental issues. Circular economy approaches provide a better way for utilization these resources in a sustainable manner. This allows maximum utilization of resources and many natural resources can be preserved and utilized for future generations. The present review provides a comprehensive illustration of biotechnological approaches for the utilization of biosolids. Various process strategies for the utilization of biosolids for the production of energy, fuels and valueadded products are discussed. The utilization of this rich organic matter under circular economy has also been described in detail.

Carbon capture through biological CO2 fixation can help to reduce the global warming potential. The use of algae systems has been identified as the most efficient and economical approach for CO2 fixation and has been realized by many developing and developed countries. However, low biomass productivity and harvesting costs limit its scale-up. To break through this technical barrier, it is necessary to study the efficiency of photosynthetic carbon sequestration in marine ecosystems, which reduced production costs significantly. In this chapter, the biological characteristics of marine algae and the principles and challenges are presented; the carbon sequestration factors of marine algae are summarized, and specific ways to improve the carbon sequestration efficiency of marine algae are proposed; subsequently, the physiological mechanisms of carbon sequestration in marine microalgae (especially carbon-concentrating mechanisms) are presented and recent advances are described, and the limitations of carbon sequestration in marine microalgae are presented. The interdisciplinary significance of the carbon sequestration efficiency of marine microalgae is further examined, and the carbon sequestration efficiency of marine microalgae is reconstructed.

Under sensommaren 2013 inventerades 14 lokaler längs Göta kanal och tre lokaler längs Kinda kanal på förekomst av larver av vandrarmusslor. Syftet var att dokumentera deras förekomst och att skaffa ytterligare erfarenhet av metoder för provtagning av mussellarver. Inventeringen skedde genom provtagning från land; kvalitativ förekomst dokumenterades genom insamling med planktonhåv medan absoluta tätheter kvantifierades i sållade vattenprov. Mussellarver förekom på samtliga de tre lokalerna nedströms sjön Roxen i Östergötland, dvs. i kanalfåran nedströms slussen i Norsholm, i Motala ström vid Kimstad och i Norrköping. Larver påträffades inte i Kinda kanal-systemet (Linköping, Sturefors, Brokind), inte vid de fyra lokalerna uppströms Roxen i Östergötland, och inte heller vid de sju lokalerna längs kanalen i Västergötland. Vid lokalen i Norsholm skedde provtagning vid två tillfällen, 10 aug och 30 aug. Larvtätheten var hög vid den första icke-replikerade pilotprovtagningen (70 ind/liter) men avsevärt lägre tre veckor senare (4,6±2,3 ind/liter). Skillnaden antyder att produktionen av larver minskade under tidsperioden vilket styrks av en signifikant förändring i larvernas kroppsstorlek som ökade från 0,139±0,030 till 0,189±0,030 mm mellan provtagningarna. En rimlig tolkning är att täthets- och storleksskillnaden var en konsekvens av en minskad nyproduktion av larver samtidigt som överlevande larver tillväxte i storlek. Kortvariga täthetstoppar av mussellarver har ofta rapporterats i andra studier. Detaljerade studier av larvernas säsongsdynamik kräver således en tät provtagning. Vuxna vandrarmusslor kan spridas inom och mellan vattensystem på föremål som förflyttas, t.ex. båtar och vattenväxter, medan larverna i första hand sprids vid förflyttning av vatten. Ballastvatten och fisksumpar i större båtar liksom skvalpvatten i mindre fritidsbåtar och kanoter är tänkbara vektorer för larver. Även vatten i behållare med agnfisk utgör en potentiell risk. Spridningen i kanalsystem underlättas naturligtvis också av slussningen av vatten och av vattnets och larvernas naturliga rörelser. Vandrarmusslor är skildkönade och eftersom larvdödligheten ofta är hög krävs vanligen att många larver förflyttas för att nya populationer ska etableras i nya vattensystem. Dessutom, för att hon- och hangameter ska ha en rimlig möjlighet att träffa på varandra krävs att kolonisatörer av båda könen etablerar sig nära varandra. När vuxna populationer väl har byggts upp kan dock spridningen inom vattensystem gå mycket fort om larvproduktionen är hög. De tätheter vi uppmätt i denna undersökning (4,6 till 70 larver per liter) är av samma storleksordning som i svenska sjöar med etablerade bestånd av vuxna musslor. Vår bedömning är därför att larvproduktionen redan är hög i Roxen och Glan och med tanke på den livliga båttrafiken finns idag inga påtagliga spridningsbegränsningar som hindrar musslornas fortsatta etablering i Göta kanal-systemet. Deras fortsatta utbredning kommer istället att bestämmas av fysikalisk-kemiska och/eller biologiska förhållanden.

Djur- och växtplankton undersöktes i Tyresö-Flaten och Albysjön, två sjöar i Tyresö kommun, söder om Stockholm, den 9 augusti 2013. Undersökningen genomfördes på initiativ av Tyresö Fiskevårdsförening. Syftena var 1) att dokumentera mängd och sammansättning av plankton 2) att bedöma om det förekommer en eventuell djurplanktonbrist som kan påverka fiskrekryteringen och 3) att bedöma sjöarnas generella näringsstatus med hjälp av växtplanktonsamhällets egenskaper. Kvantitativa djurplanktonprov togs i epi- och hypolimnion (Limnoshämtare) och kvantitativa växtplanktonprov togs i epilimnion (Rambergrör) över respektive sjös djuphåla. Metodiken var den densamma som används i den nationella miljöövervakningen och följer vedertagna standarder och Naturvårdsverkets handledning för miljöövervakning. Dessutom togs prover på djurplankton i ytvattnet på ytterligare fyra strandnära lokaler i varje sjö, med avsikt att undersöka variationen i djurplanktonförekomst inom sjöarna. Djurplanktonmängden var stor i båda sjöarna. Detta gäller alla de tre viktigaste grupperna, dvs. hjuldjur, hinnkräftor och hoppkräftor. Den rikliga tillgången på djurplankton indikerar att planktonätande fisk hade god tillgång till föda vid undersökningstillfället. Vi bedömer att djurplanktonsamhället ger underlag för en hög produktion av fisk i båda sjöarna, men med något bättre förhållanden i Albysjön, som hade en något högre djurplanktontäthet vid vissa av de strandnära lokalerna. Växtplanktonmängden var normal men dominansen av cyanobakterier var stor och flera släkten med potentiellt toxiska arter påträffades. Det motiverar fortsatt övervakning av planktonsamhället, bl.a. med hänsyn till de hälsorisker som kan råda vid bad i samband med algblomningar. En statusklassning enligt EU:s vattendirektiv med hjälp av växtplanktonsamhället visade på god status vad gäller total växtplanktonbiovolym, men otillfredsställande status vad gäller andel cyanobakterier och förekomst av indikatorarter (TPI-index). Den sammanvägda bedömningen gav klassningen måttlig näringsstatus i både Tyresö-Flaten och Albysjön. Sjöar uppströms i Tyresåsystemet lider också av höga näringshalter och vattenvårdande åtgärder uppströms kommer troligen att förbättra statusen i Tyresö-Flaten och Albysjön. Resultaten från denna undersökning ger perspektiv åt Tyresö Fiskevårdsförenings tidigare undersökningar av djurplanktonmängder ute i Tyresöfjärdarna. Djurplanktontätheten var avsevärt högre i sötvattensmiljöerna i denna undersökning än i de delar av fjärdarna som påverkas av vatten från öppna Östersjön. Ändå drabbas båda miljöerna av periodiska blomningar av cyanobakterier, ett förhållande som ännu inte är helt utrett i vetenskaplig mening.

Among ray-finned fishes that provide parental care, many spawn in constructed nests, ranging from bowls, burrows and ridges to nests made of algae or bubbles. Because a nest by definition is a construction that enhances the nest-builder's fitness by helping it meet the needs of the developing offspring, nest-building behaviour is naturally selected, as is a preference for spawning with mates that provide well-built nests. However, nest-building behaviour can also be sexually selected, when nest traits increase mating success, protect against sperm competition or nest take-overs by conspecifics. Here, we offer a systematic review, with examples of how competition for sites and location of fish nests relates to sexual selection. We examine direct and indirect benefits of mate choice linked to nest traits, and different types of nests, from a sexual selection perspective. Nest-related behaviours are often under both natural and sexual selection, and we disentangle examples where that is the case, with special attention to females. We highlight some taxa in which nest building is likely to be sexually selected, but lack of research has left them uninvestigated. Some of them are established aquarium species, making them particularly amenable for future research. Finally, we compare with arthropods, amphibians and birds.

Among ray-finned fishes that provide parental care, many spawn in constructed nests, ranging from bowls, burrows and ridges to nests made of algae or bubbles. Because a nest by definition is a construction that enhances the nest-builder's fitness by helping it meet the needs of the developing offspring, nest-building behaviour is naturally selected, as is a preference for spawning with mates that provide well-built nests. However, nest-building behaviour can also be sexually selected, when nest traits increase mating success, protect against sperm competition or nest take-overs by conspecifics. Here, we offer a systematic review, with examples of how competition for sites and location of fish nests relates to sexual selection. We examine direct and indirect benefits of mate choice linked to nest traits, and different types of nests, from a sexual selection perspective. Nest-related behaviours are often under both natural and sexual selection, and we disentangle examples where that is the case, with special attention to females. We highlight some taxa in which nest building is likely to be sexually selected, but lack of research has left them uninvestigated. Some of them are established aquarium species, making them particularly amenable for future research. Finally, we compare with arthropods, amphibians and birds.This article is part of the theme issue ‘The evolutionary ecology of nests: a cross-taxon approach’.

Males of sand gobies (Pomatoschistus spp.) spawn in shallow water and produce a courtship sound to entice females to spawn. Previous work on field-caught males shows that courtship sounds differ between males of different body condition and between species suggesting that females use acoustic information in mate choice. Here, we manipulated male body condition via feeding regimes and measured courtship and subsequent spawning decisions. Although male condition measured as lipid content differed significantly between feeding regimes, neither male visual courtship, acoustic courtship nor spawning success were affected. However, comparing the lipid content of the experimental males to field-caught males show that in nature, males are of similar condition to males in the low condition treatment group. Acoustic signals might be masked by anthropogenic noise. Thus, to test if noise may affect spawning success we exposed courting males to experimental noise, resembling boat noise. We found that females only spawned with males that produced courtship sounds and significantly less often when exposed to noise. We conclude that the information content of male courtship sound and how it relates to male condition remains elusive, but that acoustic courtship is essential for mating success, making sand gobies potentially vulnerable to noise pollution. These results will be discussed in the light of preliminary data from a field experiment using the same noise set-up where male mating success was unaffected by treatment, and a pond experiment where variation in male mating success was affected by low levels of playback noise.

Studies of colonization of new habitats appearing from rapidly changing environments increase our understanding of populations’ potential to cope with environmental changes. Here, we analyse behavioural, phenotypic and genetic variation involved in the successful establishment of the sand goby, Pomatoschistus minutus, over a steep salinity drop from 35 PSU in the North Sea (NE Atlantic) to two PSU in the inner parts of the post-glacial Baltic Sea. We show e.g. that populations are adapted to local salinity in a key reproductive trait, the proportion of motile sperm, which in itself may result in reproductive isolation caused by natural selection on immigrants. Genome variation shows strong differentiation among populations along the gradient. Sand gobies in the current Baltic Sea lineage is adapted to the low salinity in traits related to osmoregulation and reproduction, but also to both abiotic and biotic environmental factors correlated to salinity evident in traits such as vision and immune function. The salinity-biotic factors correlation is omnipresent in behavioral studies. Many loci also appear to be involved in these traits, but the specific functional mechanism (e.g., coding sequence, regulatory loci) remains to be clarified. We conclude that the first steps on the speciation continuum trajectory have been taken.

Studies of colonization of new habitats that appear from rapidly changing environments are interesting and highly relevant to our understanding of divergence and speciation. Here, we analyse phenotypic and genetic variation involved in the successful establishment of a marine fish (sand goby, Pomatoschistus minutus) over a steep salinity drop from 35 PSU in the North Sea (NE Atlantic) to two PSU in the inner parts of the post-glacial Baltic Sea. We first show that populations are adapted to local salinity in a key reproductive trait, the proportion of motile sperm, which in itself may result in reproductive isolation caused by natural selection on immigrants. Thereafter, we show that genome variation at 22,190 single nucleotide polymorphisms (SNPs) shows strong differentiation among populations along the gradient. Sequences containing outlier SNPs and transcriptome sequences, mapped to a draft genome, reveal associations with genes with relevant functions for adaptation in this environment.

Work on the Lake Victoria cichlids Pundamilia nyererei (red dorsum males, deeper water), Pundamilia pundamilia (blue males, shallower water) and related species pairs has provided insights into processes of speciation. Here, we investigate female mating behaviour of five Pundamilia species and four of their F1-hybrids through mate choice trials and paternity testing. We discuss the results in the context of the geography of speciation and coexistence. Complete assortative mating was observed among all sympatric species. Parapatric species with similar depth habitat distributions interbred whereas other parapatric and allopatric species showed complete assortative mating. F1-hybrids mated exclusively with species accepted by females of the parental species. Although consistent with reinforcement in sympatry, a closer look at our results suggests otherwise and it is more likely that pre-existing female preferences influence which taxa can co-exist in sympatry. Regardless of the mechanism, mating preferences may influence species distribution in potentially hybridizing taxa, such as in the adaptive radiations of cichlid fish. We suggest that this at least partly explains why some species fail to establish breeding populations in locations where they are occasionally recorded. Our result support the notion that mating preferences of potentially cross-breeding species ought to be included in coexistence theory.

Among all known Lake Victoria haplochromines, females alone brood the eggs and fry in their mouths, occasional exceptions in the lab notwithstanding (Seehausen 1996). Free-swimming fry are guarded for a few days (Seehausen, 1996). Long-term pair bonds are unknown, and the offspring of a single clutch may be sired by multiple males (Svensson et al., 2017). Females are generally more cryptic, whereas males are larger, more conspicuous and aggressively territorial (Seehausen, 1996). The males have bright nuptial colouration of either one of three patterns that are widespread among Lake Victoria cichlid species and referred to as ‘blue’, ‘red dorsum’ or ‘red chest’ (Seehausen et al., 1998; Seehausen and van Alphen, 1999), each of which also exists in melanic forms where the underlying colour pattern can be largely disguised. Among rocky shore cichlids, these different colour pattern groups are associated with different habitats: ‘blue’ and ‘red chest’ males breed in shallow water over gently sloping substrate, ‘red dorsum’ males breed in similar habitats but deeper, and melanic forms breed even deeper or at steeply dropping rock faces (Seehausen, 1996). The five species of the present study belong to a complex of more than 20 congeneric taxa (Seehausen, 1996; Seehausen et al., 1998). They originate from south-eastern Lake Victoria (Tanzania) around islands in the Speke Gulf; Igombe Island, Makobe Island, Ruti Island, Zue Island, not further apart than 50km (Figure 1). All have similar ecology, inhabiting rocky shores and reefs and feeding largely on plankton and benthic invertebrates (Bouton et al., 1997; Maan et al., 2008; Seehausen, 1996; Seehausen et al., 1998). Their phylogenetic relationships are complicated and characterized by lineage fusion through admixture and lineage fission through speciation (Meier et al., in press).

Work on the Lake Victoria cichlids Pundamilia nyererei (red dorsum males, deeper water), Pundamilia pundamilia (blue males, shallower water) and related species pairs has provided insights into processes of speciation. Here, we investigate the female mating behaviour of 5 Pundamilia species and 4 of their F1 hybrids through mate choice trials and paternity testing. Complete assortative mating was observed among all sympatric species. Parapatric species with similar depth habitat distributions interbred whereas other parapatric and allopatric species showed complete assortative mating. F1 hybrids mated exclusively with species accepted by females of the parental species. The existence of complete assortative mating among some currently allopatric species suggests that pre-existing mating barriers could be sufficient to explain current patterns of co-existence, although, of course, many other factors may be involved. Regardless of the mechanism, mating preferences may influence species distribution in potentially hybridizing taxa, such as in the adaptive radiation of cichlid fish. We suggest that this at least partly explains why some species fail to establish breeding populations in locations where they are occasionally recorded. Our results support the notion that the mating preferences of potentially cross-breeding species ought to be included in coexistence theory.

This report will contain the modelling and design of an operation manual and work schedule for Renova Sävenäs pre-sorting facility, the facility today is only managing the pretreatment of wood waste. The purpose of this scientific study is to further investigate what components   necessary for a complete work schedule and operation manual. The focus of this study is also to take a closer look if it is possible to switch out the wood fuel for RDF fuel. Furthermore, the amount of RDF fuel that is going to pass through the facility is 200,500, 1000 tons/week. All the information that is provided for designing the operation manual and work schedule is taken from old service instructions and the trough interviews with the personnel at the facility. This report will also contain how the facility operates during the day. Throughout this report it will be explained what RDF fuel is, how it is produced and how Renova is using it at its facility. Finally, there will be an evaluation if it's possible based on the facts presented in the report to pre-treat RDF fuel in the pre-sorting facility, and also the obstacles on why it's not feasible to do this process. 

A forager in a patchy environment faces two types of uncertainty: ambiguity regarding the quality of the current patch and risk associated with the background opportunities. We argue that the order in which the forager deals with these uncertainties has an impact on the decision whether to stay at the current patch. The order effect is formalised with a context-dependent quantum probabilistic framework. Using Heisenberg's uncertainty principle, we demonstrate the two types of uncertainty cannot be simultaneously minimised, hence putting a formal limit on rationality in decision making. We show the applicability of the contextual decision function with agent-based modelling. The simulations reveal order-dependence. Given that foraging is a universal pattern that goes beyond animal behaviour, the findings help understand similar phenomena in other fields.