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1.
We used microsatellite markers to assess the population genetic structure of the scribbled rabbitfish Siganus spinus in the western Pacific. This species is a culturally important food fish in the Mariana Archipelago and subject to high fishing pressure. Our primary hypothesis was to test whether the individuals resident in the southern Mariana Island chain were genetically distinct and hence should be managed as discrete stocks. In addition to spatial sampling of adults, newly‐settled individuals were sampled on Guam over four recruitment events to assess the temporal stability of the observed spatial patterns, and evidence of self‐recruitment. We found significant genetic structure in S. spinus across the western Pacific, with Bayesian analyses revealing three genetically distinct clusters: the southern Mariana Islands, east Micronesia, and the west Pacific; with the southern Mariana Islands being more strongly differentiated from the rest of the region. Analyses of temporal samples from Guam indicated the southern Mariana cluster was stable over time, with no genetic differentiation between adults versus recruits, or between samples collected across four separate recruitment events spanning 11 months. Subsequent assignment tests indicated seven recruits had self‐recruited from within the Southern Mariana Islands population. Our results confirm the relative isolation of the southern Mariana Islands population and highlight how local processes can act to isolate populations that, by virtue of their broad‐scale distribution, have been subject to traditionally high gene flows. Our results add to a growing consensus that self‐recruitment is a highly significant influence on the population dynamics of tropical reef fish. 相似文献
2.
Colin K. C. Wen Mary C. Bonin Hugo B. Harrison David H. Williamson Geoffrey P. Jones 《Coral reefs (Online)》2016,35(2):451-455
Acute environmental disturbances impact on habitat quality and resource availability, which can reverberate through trophic levels and become apparent in species’ dietary composition. In this study, we observed a distinct dietary shift of newly settled and juvenile coral trout (Plectropomus maculatus) following severe coral reef habitat degradation after a river flood plume affected the Keppel Islands, Australia. Hard coral cover declined by ~28 % in the 2 yr following the 2010–2011 floods, as did the abundance of young coral trout. Gut contents analysis revealed that diets had shifted from largely crustacean-based to non-preferred prey fishes following the disturbances. These results suggest that newly settled and juvenile coral trout modify their diet and foraging strategy in response to coral habitat degradation. This bottom-up effect of habitat degradation on the diet of a top coral reef predator may incur a metabolic cost, with subsequent effects on growth and survival. 相似文献
3.
D. Sun K. L. Cheney J. Werminghausen E. C. McClure M. G. Meekan M. I. McCormick T. H. Cribb A. S. Grutter 《Coral reefs (Online)》2016,35(2):427-436
The presence of bluestreak cleaner wrasse, Labroides dimidiatus, on coral reefs increases total abundance and biodiversity of reef fishes. The mechanism(s) that cause such shifts in population structure are unclear, but it is possible that young fish preferentially settle into microhabitats where cleaner wrasse are present. As a first step to investigate this possibility, we conducted aquarium experiments to examine whether settlement-stage and young juveniles of ambon damselfish, Pomacentrus amboinensis, selected a microhabitat near a cleaner wrasse (adult or juvenile). Both settlement-stage (0 d post-settlement) and juvenile (~5 weeks post-settlement) fish spent a greater proportion of time in a microhabitat adjacent to L. dimidiatus than in one next to a control fish (a non-cleaner wrasse, Halichoeres melanurus) or one where no fish was present. This suggests that cleaner wrasse may serve as a positive cue during microhabitat selection. We also conducted focal observations of cleaner wrasse and counts of nearby damselfishes (1 m radius) to examine whether newly settled fish obtained direct benefits, in the form of cleaning services, from being near a cleaner wrasse. Although abundant, newly settled recruits (<20 mm total length) were rarely (2 %) observed being cleaned in 20 min observations compared with larger damselfishes (58 %). Individual damselfish that were cleaned were significantly larger than the median size of the surrounding nearby non-cleaned conspecifics; this was consistent across four species. The selection by settlement-stage fish of a microhabitat adjacent to cleaner wrasse in the laboratory, despite only being rarely cleaned in the natural environment, suggests that even rare cleaning events and/or indirect benefits may drive their settlement choices. This behaviour may also explain the decreased abundance of young fishes on reefs from which cleaner wrasse had been experimentally removed. This study reinforces the potentially important role of mutualism during the processes of settlement and recruitment of young reef fishes. 相似文献
4.
Moheb Ali Pourgholam Hossein Khara Reza Safari Mohammad Ali Yazdani Sadati Mohammad Sadegh Aramli 《Probiotics and antimicrobial proteins》2017,9(1):32-40
A feeding trial was conducted to investigate the effects of different levels of dietary Lactobacillus plantarum on hemato-immunological parameters and resistance against Streptococcus iniae infection in juvenile Siberian sturgeon Acipenser baerii. Fish (14.6 ± 2.3 g) were fed three experimental diets prepared by supplementing a basal diet with L. plantarum at different concentrations [1 × 107, 1 × 108 and 1 × 109 colony-forming units (cfu) g?1] and a control (non-supplemented basal) diet for 8 weeks. Innate immune responses (immunoglobulin (Ig), alternative complement activity (ACH50) and lysozyme activity) were significantly higher in fish fed the 1 × 108 and 1 × 109 cfu g?1 L. plantarum diet compared to the other groups (P < 0.05). Furthermore, fish fed on various levels of L. plantarum significantly showed higher red blood cell (RBC), hemoglobin (Hb), white blood cell (WBC) and monocyte compared to those of the control group (P < 0.05). At the end of the feeding experiment, some fish were challenged with S. iniae to quantify the level of disease resistance. The mortality after S. iniae challenge was decreased in fish fed a probiotic. These results indicated that dietary supplementation of L. plantarum improved immune response and disease resistance of Siberian sturgeon juvenile. 相似文献
5.
Habitat specificity plays a pivotal role in forming community patterns in coral reef fishes, yet considerable uncertainty remains as to the extent of this selectivity, particularly among newly settled recruits. Here we quantified habitat specificity of juvenile coral reef fish at three ecological levels; algal meadows vs. coral reefs, live vs. dead coral and among different coral morphologies. In total, 6979 individuals from 11 families and 56 species were censused along Ningaloo Reef, Western Australia. Juvenile fishes exhibited divergence in habitat use and specialization among species and at all study scales. Despite the close proximity of coral reef and algal meadows (10's of metres) 25 species were unique to coral reef habitats, and seven to algal meadows. Of the seven unique to algal meadows, several species are known to occupy coral reef habitat as adults, suggesting possible ontogenetic shifts in habitat use. Selectivity between live and dead coral was found to be species-specific. In particular, juvenile scarids were found predominantly on the skeletons of dead coral whereas many damsel and butterfly fishes were closely associated with live coral habitat. Among the coral dependent species, coral morphology played a key role in juvenile distribution. Corymbose corals supported a disproportionate number of coral species and individuals relative to their availability, whereas less complex shapes (i.e. massive & encrusting) were rarely used by juvenile fish. Habitat specialisation by juvenile species of ecological and fisheries importance, for a variety of habitat types, argues strongly for the careful conservation and management of multiple habitat types within marine parks, and indicates that the current emphasis on planning conservation using representative habitat areas is warranted. Furthermore, the close association of many juvenile fish with corals susceptible to climate change related disturbances suggests that identifying and protecting reefs resilient to this should be a conservation priority. 相似文献
6.
Moheb Ali Pourgholam Hossein Khara Reza Safari Mohammad Ali Yazdani Sadati Mohammad Sadegh Aramli 《Probiotics and antimicrobial proteins》2016,8(1):1-7
We investigated the effects of Lactobacillus plantarum used as a dietary supplement on the growth performance and innate immune response in juvenile Siberian sturgeon Acipenser baerii. Juvenile fish (14.6 ± 2.3 g) were fed three experimental diets prepared by supplementing a basal diet with L. plantarum at different concentrations [1 × 107, 1 × 108 and 1 × 109 colony-forming units (cfu) g?1] and a control (non-supplemented basal) diet for 8 weeks. Growth performance indices were increased in fish fed the 1 × 108 cfu g?1 L. plantarum diet compared to the other groups. There was an increased innate immune response in fish fed the experimental diets. The highest levels of lysozyme activity, total immunoglobulin (IgM) and complement component 3 (C3) were observed in fish fed the diet containing L. plantarum at a concentration of 1 × 108 cfu g?1, but there was no significant difference in the level of complement component 4 (C4) in fish fed the experimental diets or the control diet. The present study underlying some positive effects (growth performance and immune indices) of dietary administration of L. plantarum at a concentration of 1 × 108 cfu g?1 in the Siberian sturgeon. 相似文献
7.
Patricia A. Thompson Edward F. Roseman Kevin M. Keeler Timothy P. O’Brien Dustin A. Bowser 《Environmental Biology of Fishes》2017,100(4):407-419
Monitoring changes in diets of fish is essential to understanding how food web dynamics respond to changes in native prey abundances. In the Great Lakes, Diporeia, a benthic macroinvertebrate and primary food of native benthivores, declined following the introduction of invasive Dreissena mussels and these changes were reflected in fish diets. We examined the diets of deepwater sculpin Myoxocephalus thompsonii collected in bottom trawls during 2010–2014 in the main basin of Lake Huron, and compared these results to an earlier diet study (2003–2005) to assess if their diets have continued to change after a prolonged period of Dreissena mussel invasion and declined Diporeia densities. Diporeia, Mysis, Bythotrephes, and Chironomidae were consumed regularly and other diet items included ostracods, copepods, sphaerid clams, and fish eggs. The prey-specific index of relative importance calculated for each prey group indicated that Mysis importance increased at shallow (≤55 m) and mid (64–73 m) depths, while Diporeia importance increased offshore (≥82 m). The average number of Diporeia consumed per fish increased by 10.0% and Mysis decreased by 7.5%, while the frequency of occurrence of Diporeia and Mysis remained comparable between time periods. The weight of adult deepwater sculpin (80 mm and 100 mm TL bins) increased between time periods; however, the change in weight was only significant for the 80 mm TL group (p?<?0.01). Given the historical importance of Diporeia in the Great Lakes, the examination of deepwater sculpin diets provides unique insight into the trophic dynamics of the benthic community in Lake Huron. 相似文献
8.
Gut contents of larval, juvenile, and adult specimens of the Hawaiian gobiid fish Sicyopterus stimpsoni were examined to catalog the algal flora ingested by this species. The developmental stages of S. stimpsoni examined represented hallmark points in the fish’s life cycle corresponding with major migratory and metamorphic transitions.
The algal flora was dominated by diatom species and shifted from taxa representative of a marine, planktonic community in
larval fish to a freshwater, benthic community in juvenile and adult fish. This change in diet corresponds with the migration
of larval fish to freshwater streams just prior to juvenile development in which rapid modification in mouth anatomy makes
ingestion of planktonic algal species difficult. Benthic diatoms from juvenile and adult fish assemblages represented multiple
genera that live in a narrow set of environmental conditions. These algae grow during a specific period in the development
of the benthic algal community in Hawaiian streams. This suggests a highly specialized dietary behavior that depends heavily
on continually restarting the benthic algal successional pattern, which appears to be regulated by the hydrological cycles
of streams on the island. 相似文献
9.
A. S. Grutter T. H. Cribb H. McCallum J. L. Pickering M. I. McCormick 《Coral reefs (Online)》2010,29(1):31-40
The ecological role of parasites in the early life-history stages of coral reef fish is far from clear. Parasitism in larval,
recently settled and juvenile stages of a coral reef fish damselfish (Pomacentridae) was therefore investigated by quantifying
the ontogenetic change in parasite load and comparing the growth rates of parasitized juvenile fish to those of unparasitized
ones. Parasite prevalence in two lunar pulses of Pomacentrus moluccensis was 4 and 0% for larval stage fish, 34 and 56% for recently settled fish and 42 and 49% for juveniles. A significant increase
in parasite prevalence with age group was found; the most marked increase occurred immediately after larval fish had settled.
Standard length did not model prevalence well; as length is a proxy for age, this indicates that the higher prevalence in
recently settled and juvenile fish compared with larvae was not a simple result of parasites accumulating with age. In one
of three cohorts, there was some evidence that parasitism affected the growth rate of juveniles, as measured by otolith width.
The study suggests that settling on the reef exposes young fish to potentially harmful parasites. This supports the idea that
the pelagic phase may have the effect of reducing the exposure of young fish to the debilitating effects of parasites. 相似文献
10.
Many of the most abundant small and juvenile fishes within shallow water estuarine nursery habitats consume other fish to
some degree but have rarely been considered as potentially important predators in the functioning of these systems because
of the low (<50%) average occurrence of fish in their diets. Predation by abundant minor piscivores on new recruits when they
first enter the nursery may make a significant contribution to the predation mortality of this critical life-history stage.
To determine the potential importance of minor piscivores as predators on new recruits, temporal patterns in the diets of
15 common species of minor piscivores were examined and related to the abundance of new recruits (≤20 mm FL) in biweekly seine
samples over 13 months in shallow (<1.5 m) sandy habitats in the Ross River estuary in north-eastern Queensland, Australia.
The high spatial patchiness of new recruits made it difficult to correlate their abundance with their consumption by minor
piscivores, and there was no relationship detected between the abundance of new recruits and the occurrence of fish in the
diets of minor piscivores. To gain broader insight into spatio-temporal patterns in the consumption of fish prey by minor
piscivores, we utilised a collection of fishes sampled during various studies over 6 years from 17 estuaries in the region
to examine the diets of >3500 individuals from 20 spp. of minor piscivores. Patterns in the consumption of fish prey by these
minor piscivores, especially the highly abundant sparids, sillaginids and ambassids, revealed that the low average occurrence
of fish in their diet greatly underestimated the predation pressure imposed by these on fish prey at particular locations
and times. For most sampling occasions and locations few minor piscivores consumed fish prey (consumed by 0% of individuals
examined), while occasionally a large proportion of individuals within a taxon did so (50–100% of individuals consumed fish
prey). Often at such times/locations multiple species of minor piscivores simultaneously preyed heavily on fish. When minor
piscivores consumed fish, they preyed mainly on small new recruits. Because many of these minor piscivores are relatively
recent recruits, many of the small and juvenile fishes believed to gain refuge in shallow estuarine nurseries may themselves
be important predators on fish subsequently recruiting to these habitats, and so potentially play a significant role in structuring
estuarine fish faunas and the functioning of shallow water nurseries. 相似文献
11.
Small-scale recruitment variation in a temperate fish: the roles of macrophytes and food supply 总被引:2,自引:0,他引:2
Phillip S. Levin 《Environmental Biology of Fishes》1994,40(3):271-281
Synopsis The availability of reef-related resources, particularly food and shelter can play a significant role in determining the distribution and abundance of reef fishes. Much of the structure on temperate reefs is provided by macroalgae, and variability in the density of temperate reef fishes at large spatial scales (100's of meters) can often be explained by variation in macroalgal cover or density. In this study I investigated the role of macrophytes and associated food resources on the recruitment of a temperate fish, Tautogolabrus adspersus, at a small spatial scale (0.25 m2). No relationship between the density of new recruits and the percent cover of kelp, foliose or filamentous algae was observed. Multiple regressions revealed that less than 8% of variability in recruitment could be explained by variability in macroalgal cover. However, recruits were found in higher abundance in patches containing many functional forms of seaweeds than in patches dominated by a single form. A wide variety of prey were available for use by cunner recruits; however, crustaceans and mussels were the only common components of their diet, and crustaceans were clearly the most preferred prey. The prey composition in patches where fish were present was compared to randomly selected patches. Significantly greater numbers of isopods, amphipods and newly settled mussels were present in patches where fish were present than in randomly selected patches. The data presented in this study contradict previous work that has shown algal structure to be important in determining patterns of abundance and food supply to be of little significance. A conceptual model is proposed suggesting that settling fish select habitats in a hierarchical manner largely based on their dispersal tendencies. Hierarchical selection of habitats results in different attributes of the habitat being selected during different life-history intervals. 相似文献
12.
Thermoregulation behavior of satiated and hungry juvenile sterlet Acipenser ruthenus, the Siberian sturgeon Acipenser baeri, and the goldfish Carassius auratus was studied. Significant alterations of thermoregulation behavior appear in juvenile fish one day after food deprivation. Hungry fish preferred, on average, lower temperatures, their temperature range was broader, and the locomotor activity was higher than in satiated fish. 相似文献
13.
Megan Marie Skinner Benjamin K Cross Barry C Moore 《Environmental Biology of Fishes》2017,100(8):1007-1017
Line-diffuser hypolimnetic oxygenation was initiated in North Twin Lake, Washington, in 2009 to mitigate reductions in Rainbow Trout (Oncorhynchus mykiss) and Brook Trout (Salvelinus fontinalis) habitat due to temperature-dissolved oxygen “habitat squeeze”. Previous studies demonstrated that trout populations rapidly expanded into increased hypolimnetic habitat within the first few years of oxygenation and previous short-term diet analyses indicated an effect on fish diet; however, the long-term effects on fish ecology have yet to be established. In this study, stable isotope analysis of fish liver tissue suggests relatively few differences in feeding ecology of principal coldwater fish species in North Twin Lake compared to unoxygenated South Twin Lake. When compared between lakes, Rainbow Trout and Brook Trout diets contained similar proportions of Daphnia, Chironomidae, and Chaoboridae. Littoral and epilimnetic-focused Golden Shiner (Notemigonus crysoleucas) diets were also similar between lakes. Observed similarities between Golden Shiner and trout diets suggest the effects of interspecific competition between salmonids and non-salmonids may be limiting trout growth and survival. Fisheries managers should therefore consider both habitat limitations and interspecific competition when managing for coldwater fish species in mesotrophic, dimictic lakes. 相似文献
14.
M. M. Basova 《Journal of Ichthyology》2017,57(3):467-472
This paper outlines the research findings on alterations in White Blood Cell Count of the scorpion fish Scorpaena porcus that inhabits the bays along the coastline of Sevastopol, depending on the level of environmental pollution. In the most polluted areas, the scorpion fish exhibits lymphocytosis and neutropenia. 相似文献
15.
Short-term experiments were used to isolate the detrimental effects of grazer disturbance on young corals, and determine the
stage of development at which recruits are no longer susceptible to this disturbance. Artificial substrata containing an algal
matrix and coral recruits of different life stages were exposed to grazing by epilithic algal matrix (EAM) feeding combtoothed
blennies, Salarias fasciatus. Single polyp recruits were vulnerable to grazer disturbance, while multi-polyp recruits (ca. 6–8 polyps) survived with evidence of minor damage in the form of tissue and polyp loss. The result indicates that blennies,
although small and possessing weak dentition, can negatively influence the survival of young coral recruits. The protruding
structure of micro-nubbins, representing juvenile corals were not damaged, suggesting that coral achieving that size and form
can escape such damage.
Communicated by Ecology Editor Prof. Peter Mumby 相似文献
16.
Kamath Mukund Manali Rex Arunraj Thangarathinam Kumar Mohandass Ramya 《Journal of applied phycology》2017,29(3):1279-1286
Arthrospira species, under the name ‘Spirulina’, are used as food supplement for its protein, vitamins, and minerals which have several health benefits. Cyanobacterial toxins including microcystins can possibly contaminate these dietary supplements causing hepatotoxicity, tumour formation, and other disorders. The safe use of dietary supplements necessitates the need to assess such toxins in the algal food supplement. The methods which evaluate these dietary supplements should be highly sensitive, cost-effective, and rapid. In this study, multiplex HRM qPCR analysis was used to detect microcystin (MC)-producing cyanobacteria in Spirulina dietary supplements. The multiplex HRM qPCR detection limit was found to be 25 ag of mcyB spiked in a standard concentration of pcb (25 pg). Two distinct melt curves characteristic of pcb (Tm 82.8 ± 0.07 °C) and mcyB (Tm 77.9 ± 0.05 °C) were observed. Microcystin contamination was detected only in the fish food supplements and not in human dietary supplements of Spirulina. Liquid chromatography–high-resolution mass spectrometry analysis further confirmed the presence of the congeners of microcystin in the identified positive samples. 相似文献
17.
O. A. Stepanova 《Russian Journal of Marine Biology》2016,42(2):123-127
Monitoring of the Black Sea algal viruses in Sevastopol bays and Crimean water areas has been carried out since 2002. Based on the methods that were developed and patented by the author, more than 200 strains of algal viruses of five species of microalgae that are new to science were isolated: TvV (Tetraselmis viridis virus), DvV (Dunaliella viridis virus), PtV (Phaeodactylum tricornutum virus), PpV (Prorocentrum pusillum virus) and IgV (Isochrysis galbana virus). For the first time in the Black Sea, the Emiliania huxleyi virus (EhV) of microalgae was isolated. Using the method of electron microscopy, the Black Sea algal viruses were identified as icosahedral virions with respective sizes of 56–60, 45–48, 50–53, 88–92, and 128–132 nm, for the TvV, PtV, DvV, PpV and IgV viruses. The EhV size, as determined by the method of filtration, was within the range of 50–200 nm. In the IgV and EhV viruses we revealed a viral envelope. Based on their characters the isolated algal viruses were attributed to the Phycodnaeviridae. The maximum number of algal viruses was observed in the spring and autumn seasons, which is typical for their host phytoplankton species. The Black Sea algal viruses, TvV, PpV, IgV, and EhV, displayed no strict species specificity and have a wide range of available hosts. 相似文献
18.
19.
The behaviour of juvenile fishes is critical in establishing the link between recruitment and subsequent adult populations. If juvenile fishes move, they can respond to variation in local conditions before adult home ranges are established. Alternatively, if juveniles establish fixed home ranges at settlement, their decisions may determine future population densities at small spatial scales. Field observations and translocations revealed that juvenile rabbitfishes (Siganus corallinus and S. doliatus) have small home ranges and strong homing abilities (covering 6 m in 1 h or 36 m within 24 h). Only four of 22 individuals failed to return; all were transferred up-current, suggesting that olfaction is important in homing. Small home ranges and strong homing tendencies in juvenile herbivores suggest that decisions made by recruits will impact the spatial extent of both adult fishes and the functional roles they play within ecosystems. 相似文献
20.
Studies on the effect of eutrophication on the ecology of shallow lakes, usually pay scant attention to changes within the
epiphytic algal community, though the contribution of this to the ecosystem dynamics is transcendental. In order to test the
influence of nutrient loadings and fish densities in the structure of algal epiphyton in a shallow lake, an experiment was
performed using in situ mesocosms. Nutrient additions were related to significant decreases in the total epiphyton biovolume
and that of bacillariophyceans and zygnematophyceans, but with increases in the abundance of cyanobacteria. The different
response of algal groups at the higher nutrient concentrations (increases or decreases in their abundance and/or biovolume)
can be related to their ecophysiological constraints such as different resistance to toxicant ammonium accumulation. Plant-associated
macroinvertebrates numbers were positively correlated with total numbers of epiphyton. The presence of planktivorous fish
enhanced the abundance and biovolume of all algal groups, except cyanobacteria. Fishes enhanced the abundance of plant-associated
animals and of total epiphyton. Fish indirect effects (e.g., nutrients release) and their dietary particularities were among
the factors that together with nutrients influenced epiphyton growth. The role of indirect effects of fishes and the importance
of their dietary particularities are stressed as key factors to understand the processes controlling epiphyton ecology and
the food web structure of shallow lakes.
Handling editor: D. Ryder. 相似文献