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1.
The spawning season, spawning grounds, and migration of the myctophid fish Diaphus theta were studied in the western North Pacific, based on seasonal sampling and estimation of hatching dates. The peak abundance
of larvae was observed in July in the transition waters between the Oyashio and Kuroshio fronts. The spawning season ranged
from late March to early September, with a peak from May to July. Larvae and juveniles <40 mm in standard length were distributed
in the transition waters, whereas larger individuals were collected in the Oyashio and the Western Subarctic waters. These
results indicate that this species undergoes a horizontal spawning migration from the Oyashio and Western Subarctic waters
into the transition waters crossing the Oyashio front.
Received: July 11, 2002 / Revised: October 2, 2002 / Accepted: October 15, 2002
Acknowledgments We are grateful to the captains, officers, and crew of FRV Hokko-Maru, FRV Tankai-Maru, and RV Hakuho-Maru for their assistance at sea. We thank Dr. H. Saito and Mr. H. Kasai for their cooperation in field sampling, and Dr. C. Sassa
for his assistance with larval fish taxonomy.
Correspondence to:Masatoshi Moku 相似文献
2.
Combining limnological and palaeolimnological approaches in assessing degradation of Lake Pskov 总被引:2,自引:2,他引:0
Mihkel Kangur Külli Kangur Reet Laugaste Jaan-Mati Punning Tõnu Möls 《Hydrobiologia》2007,584(1):121-132
Historical spawning grounds for sea lampreys (Petromyzon marinus L.) in most Portuguese river basins are becoming inaccessible due to the construction of impassable dams and/or weirs. Studies
like the one described in this paper are particularly important in areas like the Vouga river basin, where there is a considerable
fishing effort from both professional fishermen and poachers. In fact, for management and conservation purposes, it is important
to clarify several aspects of the sea lamprey spawning run in this particular watershed. Therefore, a total of 30 radio tagged,
migrating sea lampreys were released in the River Vouga and some of its main tributaries during 2004 and 2005. Results from
the tracking sessions were used to determine the effect of poaching on the spawners’ population and the characteristics of
the resting sites used during the upstream movement. The rivers’ stretches were also characterized according to the type of
substrate present in the riverbed and flow type, in order to determine its aptitude to constitute appropriate spawning habitats
for sea lampreys. We have identified in the upstream stretches of River Vouga, and in the tributary River Caima, characteristics
that are particularly suitable for the construction of nests by the spawners. Presence of larvae provided evidence that spawners
migrated into the River Vouga’s upper reaches. However, abundance and age class diversity appeared to be higher downstream
of Sernada and Carvoeiro weirs, corroborating the telemetry data which suggested difficulty in passing these obstacles during
low precipitation years. In the River Caima, migration was most predictable, which might be related to daily water releases
from a small hydropower dam at dusk, that stimulated the lampreys to resume migration. Poaching has had a considerable negative
effect on the success of the tagged lampreys’ migration: 76% of the animals released during 2005 were captured.
Electronic supplementary material Supplementary material is available for this article at and accessible for authorized user 相似文献
3.
The sperm allocation pattern of a copulating marine cottid fish, Alcichthys alcicornis, was investigated. A total of 86 mating events using six males were conducted in aquarium tanks over 10 days, and in 36 of
them, spermatozoa were collected using a false copulation method. Males released 3–8 × 108 spermatozoa in early events, with the number decreasing gradually during subsequent mating events. This sperm allocation
was represented as an “early investment and tapering” pattern. It was discussed why males have significantly higher sperm
release in early spawning events. The reproductive behavior consists of spawning and subsequent copulation. Spermatozoa have
the ability to fertilize eggs from multiple clutches, and in earlier produced clutches the level of sperm competition should
be relatively low. In addition, if early spawn happens to be the first spawn with a female, spermatozoa that are released
into the water column after spawning are responsible for fertilizing the female’s first clutch. The probability of this occurring
should decrease dramatically as the season progresses, due to the highly synchronous seasonal spawning of females. All of
these factors should select for high sperm numbers in early ejaculates. Based on such reproductive ecology of A. alcicornis we hypothesize that this sperm allocation pattern is an adaptive reproductive strategy in response to egg availability and
sperm competition occurring within the ovarian cavity. 相似文献
4.
5.
Hydroacoustic research conducted on chokka squid (Loligo reynaudi d’Orbigny, 1845), off the east coast of South Africa from 1994–2005, has led to the development of an innovative stock assessment
technique, perhaps applicable to all loliginids that migrate inshore to spawn. This technique combines hydroacoustic biomass
estimates made on the spawning concentrations inshore, and minimum biomass estimates made both inshore and offshore using
demersal surveys employing the swept-area method. The hydroacoustic estimate uses an improved method to obtain target strength
measurements, and squid concentrations are individually mapped from a small boat with a towed transducer. This method may
be used even during intense fishing operations because of the manoeuvrability of the small boat inside a tight cluster of
fishing vessels. Biomasses of the individual concentrations are then summed. The inshore biomass, also includes dispersed,
mature squid migrating between concentrations, this is assessed using a concentration stability factor. The biomass of dispersed
squid offshore is again calculated using the swept-area method, a well known demersal survey methodology. The biomass of concentrated
(spawning) squid offshore is calculated using the same proportions between concentrated and dispersed squid which were found
inshore. All four components are then summed to calculate the total biomass. The result obtained is subject to the effect
of complex temporal dynamics, as new animals are recruited to the adult pool and those recently assessed migrate to other
sectors of the distribution area. 相似文献
6.
K. M. Gorbatenko A. V. Nikolayev A. L. Figurkin E. N. Il’inskii 《Russian Journal of Marine Biology》2009,35(7):579-592
The total biomass of jellyfish on the shelf of the eastern Sea of Okhotsk in the summer is estimated as 1672700 tons according
to the results of hydroacoustic measurements and 901000 tons by the method of squares. The use of hydroacoustic technologies
makes evaluation of the actual stock and range of medusae more accurate, and the further enhancement and perfection of the
hydroacoustic method based on multifrequency measurements enables one to obtain more reliable estimates. A significant increase
(nearly 25 times) of the total jellyfish biomass takes place in the summer period. Cyanea prevailed in biomass in the spring and Chrysaora melanaster prevailed in the summer. Some species showed considerable expressed spatial differentiation of distribution and affinity
to certain environmental conditions. The studied species were almost exclusively zoophages. Their algal diet consisted mainly
of diatom algae. Scyphomedusa’s diet mainly included the so-called “peaceful” zooplankton, viz., euphausiids and copepods
(as a rule, over 50% the mass), at the same time carnivorous zooplankton, saggits, amphipods, and small medusae also formed
a substantial share of their diet. One individual of the predominant jellyfish species consumes a total of 6.1 to 70.5 kcal
during its lifecycle, which corresponds to 79.1–513.0 g of raw organic material, assuming 70% assimilability. The relatively
low demand for food of this sort can be explained by the low caloric value of the jellyfish body, 96–97% of which consists
of water. The distribution and composition of the jellyfish prey show that scyphomedusae exert the greatest influence on the
nekton community, as they concentrate in the shelf area of the eastern part of the sea, at walleye pollock spawning sites.
There the larvae of bottom invertebrates, including commercially valuable organisms, such as crab and shrimp, are also consumed.
In the summer, jellyfish eat nearly 100 billion eggs and 20 billion larvae of walleye pollock, as well as 130 billion decapod
(mostly crab) larvae each day, which corresponds to 0.03% of the eggs and 0.003% of the larvae of walleye pollock and 0.003%
of the decapod larvae in the estimated stock. 相似文献
7.
Patterns of migration between feeding and spawning sites in a coral reef surgeonfish 总被引:1,自引:0,他引:1
Many coral reef fishes exhibit regular localised migrations between feeding and spawning areas, but the factors affecting
these migration patterns, such as the distance, frequency and spawning site fidelity are poorly understood. The aim of this
study was to investigate the patterns of migration to spawning sites of the surgeonfish, Ctenochaetus
striatus (Acanthuridae). We explored relationships amongst an individual’s size and sex, the distance and frequency it migrated from
its feeding area to spawning sites, fidelity to particular spawning sites and the number of individuals that aggregated to
spawn. In order to achieve this, 406 C. striatus were captured and tagged on inshore reefs in Kimbe Bay (5°30′S 150°6′E), New Britain, Papua New Guinea. Tagged individuals
were consistently observed within spatially discrete but overlapping feeding areas (maximum diameter averaging <13 m). The
mean distance migrated was 58 m (ranging from 2 to 291 m). No tagged individuals were witnessed spawning at more than one
site. Whilst most individuals (n = 88) migrated to the spawning site that was closest to their feeding areas, those that migrated to sites further away (n = 9) always spawned at sites where the number of conspecifics aggregating was larger. Neither the size nor the sex of individuals
limited migration distance. However, males migrated significantly more frequently than females (on average once every 2 days
vs. once every 3 days), and migration frequency was positively correlated with size in females. Migration distance did not
affect the frequency with which individuals spawned. Whether patterns of migration are determined by cost-benefit optimisation,
tradition, or an alternative mechanism is unknown. 相似文献
8.
Species’ impacts on primary production can have strong ecological consequences. In freshwater ecosystems, Pacific salmon (Oncorhynchus spp.) may influence stream periphyton through substrate disturbance during spawning and nutrient subsidies from senescent
adults. The shape of relationships between the abundance of spawning salmon and stream periphyton, as well as interactions
with environmental variables, are incompletely understood and may differ across the geographic range of salmon. We examined
these relationships across 24 sockeye salmon (Oncorhynchus nerka) spawning streams in north-central British Columbia, Canada. The influence of salmon abundance and environmental variables
(temperature, light, dissolved nutrients, water velocity, watershed size, and invertebrate grazer abundance) on post-spawning
periphyton abundance and nitrogen stable isotope signatures, which can indicate the uptake of salmon nitrogen, was evaluated
using linear regression models and Akaike Information Criterion. Periphyton nitrogen stable isotope signatures were best described
by a positive log-linear relationship with an upstream salmon abundance metric that includes salmon from earlier years. This
suggests the presence of a nutrient legacy. In contrast, periphyton abundance was negatively related to the spawning-year
salmon density, which likely results from substrate disturbance during spawning, and positively related to dissolved soluble
reactive phosphorus prior to spawning, which may indicate phosphorus limitation in the streams. These results suggest that
enrichment from salmon nutrients does not always translate into elevated periphyton abundance. This underscores the need to
directly assess the outcome of salmon impacts on streams rather than extrapolating from stable isotope evidence for the incorporation
of salmon nutrients into food webs. 相似文献
9.
Chinese sturgeon (Acipenser sinensis) is a protected anadromous fish species. The migration pattern of the fish has been blocked by the construction of Gezhouba
Dam, reducing the natural spawning site length to less than 7 km along the Yangtze River. However, the fish has since established
an alternative spawning ground in the narrow reach downstream of Gezhouba Dam. To enhance navigation, a Separation Levee Project
(SLP) was implemented in the new-found spawning habitat of the fish. To therefore evaluate the effect of the SLP on Chinese
sturgeon spawning habitat suitability, the conditions in the spawning habitat were simulated using River2D (a two-dimensional
hydrodynamic model). Two main approaches (habitat kinetic energy and circulation metrics) were used in the simulation. The
study showed that SLP only slightly changed the physical conditions in the spawning habitat. Using hydrodynamic simulation,
the weighted usable area (WUA) before and after the SLP construction was also computed and habitat preference curve developed
for water depth and velocity. On the average, SLP reduced WUA—a finding that was consistent with field-measured data. Based
on WUA, the habitat conditions were more sensitive to SLP proximity than metrics based on velocity gradients. SLP posed detrimental
impacts on the suitability of spawning habitats of Chinese sturgeon. The findings in this study provide further basis for
the protection and restoration of Chinese sturgeon spawning habitats in especially the lower reach of Yangtze River. 相似文献
10.
M. D. Bordalo S. M. F. Ferreira P. G. Cardoso S. Leston M. A. Pardal 《Hydrobiologia》2011,671(1):13-25
The Mondego Estuary (Portugal) underwent major modifications in the late 1980s, because of eutrophication, for which it was
developed a restoration programme that has been effective in recovering seagrass beds. Recently, this system has been affected
by successive weather extremes: floods, droughts, and heat waves. The effect of these multiple stressors on a Cyathura carinata (Isopoda) population has been evaluated, through a long-term data series (16 years) in a seagrass bed, an intermediate area,
and a sand flat. A well age-structured and abundant population of C. carinata was observed in the sand flat, in contrast with the seagrass bed and intermediate area. After introducing the restoration
measures, C. carinata’s abundance increased even in the stations where it was formerly scarce. This recovery was compromised by successive extreme
events. C. carinata declined severely in terms of total abundance and growth production during the 2003 summer heat wave, at the sand flat, also
endangering its reproductive success. Floods and droughts affected dispersion of the individuals, which was reflected in the
population’s density and production. Nevertheless, this isopod had great resilience, recovering successfully after disturbances.
In contrast, the population of C. carinata had less resilience in the seagrass bed and intermediate area, being unable to recover after a succession of disturbances,
which may threaten the success of this species in the system. Because the frequency and intensity of weather extremes are
expected to continue to increase in a scenario of global climate change, their repercussions will affect such populations,
which will have difficulty surviving. This will have severe implications on the functioning of the whole ecosystem. 相似文献
11.
JOSEPH J. LUCZKOVICH MARK W. SPRAGUE STEPHEN E. JOHNSON R. CHRISTOPHER PULLINGER 《Bioacoustics.》2013,22(2-3):143-160
ABSTRACT Exact locations of spawning areas used by marine fishes are needed to design marine reserves and estimate spawning stocks. The location of spawning areas of soniferous fishes such as weakfish Cynoscion regalis can be determined by means of passive hydroacoustic surveys. We conducted nocturnal hydrophone surveys at 12 locations in Pamlico Sound in May of 1996 and 1997. Digital audio tapes were made of weakfish “purring” sounds, the tapes were analyzed spectrographically and compared with ichthyoplankton surveys taken at the same stations and times. All weakfish “purring” sounds were recorded at stations near inlets. Maximum sound pressure levels recorded after sunset were 127 dB (re 1 (μPa) for individual weakfish, but reached a maximum of 147 dB when weakfish and other fish were producing sounds simultaneously. The maximum distance that an individual weakfish “purr” can be detected above the background sound, assuming a cylindrical spreading model, is approximately 50 m. There was a strong association (r = 0.78) between the log10— transformed abundance of early-stage sciaenid-type eggs and maximum sound pressure levels, with the greatest numbers occurring at the inlet stations. These results suggest that passive hydroacoustic surveys can be used to delimit spawning areas for conservation and management purposes. 相似文献
12.
Kenneth M. Olsen 《Oecologia》1996,109(1):114-121
Assessing the relative contributions to seed set for each of a plant species’ floral visitors provides an indication of the
relative influence of these visitors on the plant’s reproductive success. This study examined pollinator activity and seed
set in a population of Heterotheca
subaxillaris, a species that exhibits a floret dimorphism (heads bearing disk and ray florets), and that is visited by both generalist
foragers and specialist bees. Visits by nine bee genera and one genus of skipper were recorded in the study population. During
the period of study, these insects varied in their relative abundance, in their foraging activity on a head, and in their
pollination effectiveness. The pattern of pollination effectiveness shown by the different pollinators was similar for both
floret types, although seed set was higher overall for ray florets. Pollinator importance, calculated as the product of pollination
effectiveness and relative abundance, was dictated by a pollinator’s relative abundance. The single specialist bee species
observed in the study population proved to have neither higher pollination effectiveness nor higher pollinator abundance than
other pollinators. This would suggest that H. subaxillaris is not under strong selective pressure to co-specialize with its specialist visitor.
Received: 21 December 1995 / Accepted: 20 June 1996 相似文献
13.
Yasufumi Fujimoto Yutaka Ouchi Takeshi Hakuba Hiroaki Chiba Munehico Iwata 《Environmental Biology of Fishes》2008,81(2):185-194
We investigated the influence of human activities on the spawning migration of the mud loach, Misgurnus anguillicaudatus. Mud loaches migrate from rivers to paddy fields for spawning. In this study, the number of adult loaches in paddy fields
showed a peak in late May and rapidly decreased in July. In early July, water is discharged from paddy fields in order to
allow the fields to dry for a few weeks, and water is again supplied later. The spawning season of the loaches probably spans
from mid May to August; this was concluded by observing physiological indicators such as the gonad somatic index, oocyte maturity
and serum levels of testosterone, estradiol-17β and 17α, 20β-dihydroxy-4-pregnen-3-one. When the loaches mature, they migrated
to paddy fields if they could swim upward through the drainage ditches. However, the drainage ditches of modern paddy fields
were reconstructed to deepen the water levels. The artificial drought of the rice culture management led to a discharge of
water and loaches from the paddy fields during their spawning season. These results indicate that modern rice cultivation
causes obstruction of the migration route and loss of spawning grounds; consequently, loaches use limited space and period
of the paddy field for their spawning. 相似文献
14.
Céline Arzel Johan Elmberg Matthieu Guillemain Michel Lepley Fabrice Bosca Pierre Legagneux Jean-Baptiste Nogues 《Journal of Ornithology》2009,150(1):61-73
Two frequent assumptions about the evolution of long-distance migration in birds are that they travel long distances annually
to reach food-rich areas for breeding, and that they time their migratory journey to be at staging sites when the latter provide
the best feeding conditions. These assumptions have rarely been properly tested, and there is no study in which a species’
major food types have been measured by standardized methods throughout a flyway and over a large part of the year. We here
present such data for Eurasian teal (Anas crecca), converted to a common energetic currency, and collected at wintering, spring staging and breeding sites. Teal did not time
migration to maximize local food abundance; most birds left wintering and spring staging sites before a sharp increase in
invertebrate food abundance occurred. On the other hand, hatching of ducklings coincided with a peak in invertebrate food
abundance on boreal breeding lakes. Mean overall food abundance (invertebrates and seeds combined) did not differ between
wintering sites in southern France and breeding sites in northern Sweden at the time of breeding. Our results are inconsistent
with the hypothesis that long-distance migration in dabbling ducks has evolved because adult birds gain an immediate pay-off
in increased food abundance by flying north in spring. However, our data confirm a selective advantage for breeding at higher
latitudes, because hatching of ducklings may coincide with a peak in invertebrate emergence and because longer days may increase
the duration of efficient foraging. 相似文献
15.
Richard S. Nemeth Jeremiah Blondeau Steve Herzlieb Elizabeth Kadison 《Environmental Biology of Fishes》2007,78(4):365-381
This study compared the spatial and temporal patterns of red hind, Epinephelus guttatus, movement and migration from annual spawning aggregations on St Thomas (STT) and St Croix (STX), United States Virgin Islands.
Around STT E. guttatus migrated 6–33 km from a functional spawning migration area of 500 km2 and around STX E. guttatus migrated 5–18 km from an area of 90 km2. Similarities between sites were found in regards to timing of movement, temporal and spatial changes in sex ratios, annual
and lunar predictability and were synchronized with environmental cues. E. guttatus spawning aggregations in the Virgin Islands occur between the winter solstice (i.e., after December 20) and about February
20 of any year and show a distinctive peak 20–40 days after the winter solstice. Spawning typically occurred during periods
of declining seawater temperature and slacking currents within a temperature range of 26–27.5°C and current speed of 2.5–3.5 cm s−1. Males arrived early to spawning sites and stayed longer than females. These gender-based behavioral patterns are important
to E. guttatus reproductive dynamics and must be factored into future studies and the design of fisheries regulations to ensure sustainability
of spawning aggregation sites. The predictability of E. guttatus spawning aggregations relative to the winter solstice will be extremely beneficial for defining the temporal and spatial
aspects of area closures. The consistency and synchrony of movement and migration will improve both the efficiency of planning
research and monitoring programs and directing enforcement activities during critical time periods. Applying this knowledge
strategically will maximize the limited resources available for research and enforcement and lead to greater protection of
spawning aggregations. 相似文献
16.
Effect of spatial differences in growth on distribution of seasonally co‐occurring herring Clupea harengus stocks
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The mechanisms most likely to determine the distribution of the two major herring Clupea harengus stocks in their common early summer feeding ground in the eastern North Sea, Skagerrak and Kattegat were investigated through analysis of acoustic survey data from six consecutive years. No change was detected in biomass of North Sea autumn spawning C. harengus (NSAS) over time, whereas the biomass of western Baltic spring spawning C. harengus (WBSS) declined severely. Analyses of centre of abundance by stock showed no change in NSAS distribution, whereas the WBSS changed to a more western distribution over time. Contrary to previous perception of the juvenile migration, NSAS were found to leave the study area at the age between 1 and 2 years and WBSS 1 year olds were encountered in the Skagerrak. The estimated parameters of von Bertalanffy growth equations showed marked differences between areas with fish in the eastern part of the area having the lowest size at age at all ages. Further, their growth conditions appeared to deteriorate progressively over the period studied. Both NSAS and WBSS showed the highest condition in the North Sea and Skagerrak while condition was substantially lower in age Kattegat. The westward movement of spring spawners over time suggests that growth rate and possibly density of conspecifics influence the migration pattern and distribution of C. harengus in the area. In contrast, there was no evidence to suggest that distribution was constant over time within stocks or that distribution reflected size‐dependent limitations on migration distance. 相似文献
17.
We analyzed the environmental determinants of the regional distribution of Bonelli’s eagle (Aquila fasciata) in Spain (ca. 500,000 km2), taking into account its frequency of occurrence on UTM blocks of 50 × 50 km. We found that the distribution pattern of
Bonelli’s eagle was a highly predictable phenomenon based on climate, vegetation and interspecific relationships. The proportion
of sunny, anticyclonic days, per year (i.e., high levels of solar radiation) was the main environmental predictor explaining
the distribution and abundance pattern of the Bonelli’s eagle. Sparse plant formations (mainly shrublands) had also a positive
effect, while altitude, agricultural land and deciduous forests had a negative influence. The relative abundance of one of
its main preys, the Red Partridge (Alectoris rufa), favored the probability of occurrence of Bonelli’s eagle, but only in the less sunny areas located in the north of Spain.
The relative abundance of its main competitor, the Golden eagle (Aquila chrysaetos), was slightly but positively correlated with both the distribution and the abundance of the Bonelli’s eagle in the Spanish
portion of the Iberian Peninsula, probably due to similarities in their habitat preferences. Finally, we did not find further
regional effects of the variables describing the degree of human pressure (density of roads, urban cover, and length of power
lines). 相似文献
18.
Quantative estimates of abundance of anadromous Kamchatka steelhead Parasalmo mykiss in the period of its maximum spawning migration in the shallow Utkholok River by the instrumental method using Didson dual-frequency
identification sonar are presented. Equipment and methods are described for the stationary observation of spawning run of
Kamchatka steelhead through the river cross section and mobile surveys of the water area of the Utkholok R. As a result of
stationary observations, the abundance and size composition of Kamchatka steelhead migrating to the upper reaches of the river
are determined. Peculiarities of the diurnal dynamics of migration of Kamchatka steelhead characterized by two sharp peaks
of run intensity in the morning and evening were revealed. During the period of observations from September 22 to October
20, 2007, in the seasonal dynamics of migration two peaks of intensity of run of Kamchatka steelhead depending on an abrupt
decrease in water temperature by 2°C were also registered. Mobile surveys supplied data on the abundance and size composition
of Kamchatka steelhead in the surveyed water area of the river, on its spatial distribution, and dynamics of accumulation
of fish in the river. The abundance of Kamchatka steelhead in the river almost doubled every three-four days and the spatial
distribution was aggregated, producing maximum concentration mainly in areas of increasing depth and channel meandering before
and after riffles. Comparison of the results of assessment of abundance of Kamchatka steelhead that arrived for spawning in
2006 and 2007 showed significant fluctuations in population abundance. 相似文献
19.
A video camera inside an underwater housing was used to record the spawning activities of lake trout, Salvelinus namaycush, in Kushog Lake, Ontario (Canada). Contrary to the commonly accepted belief describing lake trout as the only salmonine to
spawn exclusively at night, the recordings were taken during the day. Lake trout spawning behaviour is described in detail
and compared with other salmonine species. The loss of female “nest-building” and assumption of a novel itinerant strategy
during which females travel across the breeding grounds accompanied by a group of males, is considered to be an important
change in the evolution of the lake trout’s unique mode of spawning. 相似文献
20.
The significance of sound interception to males of the bicolor damselfish,Pomacentrus partitus,during courtship 总被引:1,自引:0,他引:1
Todd N. Kenyon 《Environmental Biology of Fishes》1994,40(4):391-405
Synopsis Playback experiments conducted in the field and the laboratory demonstrated the use of sound interception in bicolor damselfish,Pomacentrus partitus. Two courtship sounds produced by male bicolors: the ‘chirp’ which occurs at the initiation of courting and the ‘grunt’ which
occurs near the termination, just prior to spawning, were found to hold different meanings to intercepting male competitors.
Males responded to grunt playback with directional swimming towards the sound source and increased courtship behavior. No
directional response was observed during chirp playback. The grunt sound appears to indicate that a spawn-ready female is
present near the sound source. Males therefore move towards it, likely to interfere with the imminent spawning or to gain
a possible spawning partner. Such is not observed in response to chirps, as little advantage would be gained by moving to
the source of a sound which is known to serve as an ‘advertisement’ or ‘territorial keep-out’ signal. Thus, upon intercepting
a neighbor's chirps, males exhibit courting within their own territory, or directly court a nearby female. 相似文献