Spawning patterns in the leopard grouper, <Emphasis Type="Italic">Mycteroperca rosacea</Emphasis>, in comparison with other aggregating groupers

We documented the spawning patterns of the leopard grouper, Mycteroperca rosacea, from April to June 2005 in the central Gulf of California, Mexico to draw comparisons with other aggregate-spawning groupers and provide information useful for management of their fishery. Adults formed spawning aggregations of 150 to >700 individuals at specific sites, and spawning occurred daily at these sites from late April through early June. Courtship occurred throughout the day, but spawning was restricted to the evening hours. Adults spawned in groups of 6–40 fish, and pair-spawning was not observed. The group-spawning behavior of adults and the gonosomatic indices of mature males (maximum = 7.2%) suggest that sperm competition was present. The site-specificity of leopard grouper spawning aggregations and diel spawning period were typical of most aggregating groupers, and the size and structure of these aggregations was similar to other species in the genus Mycteroperca. Leopard grouper behavior patterns were unusual in that spawning aggregations persisted for extended periods, spawning was not synchronized with the lunar cycle, and adults aggregated during non-spawning periods. The extensive duration and site-specificity of spawning aggregations and the propensity of M. rosacea to form aggregations year-round increases the vulnerability of the species to overfishing. Policies that limit harvest from these aggregations are needed to improve the management of leopard grouper fisheries in the Gulf of California.     

Seasonality in reproduction of the deep-water pennatulacean coral Anthoptilum grandiflorum

The deep-sea pennatulacean coral Anthoptilum grandiflorum exhibits a cosmopolitan distribution and was recently determined to serve as habitat for other invertebrates and fish larvae in the northwest Atlantic. Colonies collected at bathyal depths between 2006 and 2010 in eastern Canada were analysed to determine their fecundity and characterize spatial and temporal trends in their reproductive cycle. Anthoptilum grandiflorum is a gonochoric broadcast spawner with a sex ratio that does not differ significantly from equality (although one hermaphrodite colony was observed). In male colonies, all the spermatocysts synthesized become mature over the annual cycle, while only ~21 % of the initial production of oocytes reaches maturity in female colonies. Female potential fecundity based on mature oocytes just before spawning was on average 13 oocytes polyp^?1; male potential fecundity was 48 spermatocysts polyp^?1. The spawning period of A. grandiflorum differs between geographic regions, from April (in southern Newfoundland) to July (in Labrador), closely following regional spring phytoplankton blooms after accounting for the deposition of planktic detritus. Release of oocytes by a live colony held in the laboratory was recorded in April 2011, coincident with field data for similar latitudes. Seawater temperatures at the time of spawning were around 3.6–4.8 °C in all regions and in the laboratory. Early stages of gametogenesis were detected in colonies collected shortly after the spawning season, and early and late growth stages occurred successively until December. Mature colonies were observed between April and July (depending on latitude). The diameter of mature oocytes (~1,100 μm maximum diameter) is consistent with lecithotrophic larval development.     

Reproductive parameters of female Hawaiian damselfish<Emphasis Type="Italic"> Dascyllus albisella</Emphasis> with comparison to other tropical and subtropical damselfishes

The reproductive ecology of female Hawaiian damselfish Dascyllus albisella (Gill) was studied at Kaneohe Bay, Oahu, Hawaii (21°27'N; 157°47'W) during two peak reproductive seasons (June–September 1997, July–August 1998). In both years, spawning occurred cyclically every 5–7 days, with all spawning in the study area in each cycle concluding within 2–3 days. The study period encompassed 16 spawning cycles in 1997 and 10 cycles in 1998. Some females spawned in almost all cycles, whereas others spawned in as few as one. Mean spawning interval of individual females ranged from 6.4 to 11.7 days in 1997 and from 5.5 to 29.0 days in 1998. Batch fecundity increased exponentially with body length, and ranged from 23,100 to 52,800. Spawning duration increased linearly with body length and ranged from 20 to 286 min. On a single day, large females spawned earlier than small females. Females mated with several different males over a season, but typically mated with only one male on a single spawning day. Female spawning frequency and interval, spawning duration, batch fecundity, as well as diel timing of spawning in D. albisella were comparable to those reported for other large, planktivorous, non-territorial damselfishes.     

Long-term experiments on lifespan, reproductive activity and timing of reproduction in the Arctic copepod Calanus hyperboreus

Several experiments were conducted with starved and fed females of the Arctic copepod Calanus hyperboreus (1) to investigate their lifespan, reproductive period, egg production and egg viability; (2) to study the effect of origin, i.e., Atlantic and Arctic Waters in the Greenland Sea, on the timing of reproduction; and (3) to study the effect of time of collection on the onset of reproductive activity as a first approach to study control mechanisms of the reproductive cycle. Females collected in October produced up to 1,000 eggs and had a maximum lifespan of 164 days without feeding, whereas fed females produced up to ca. 6,000 eggs and survived up to 806 days. These observations support earlier assumptions that females were multiannual-iteroparous, i.e., capable to spawn in successive years, which would be unique for calanoid copepods. In starved females, clutch size decreased significantly with each spawning event. Viable eggs were produced during most of the life time. There was no difference in the timing of reproductive activity between females from the West Spitsbergen Current and the Greenland Sea Gyre. Fed and starved females collected in May and June began to spawn circa 2 and 4 months after collection, respectively, whereas females collected in August and October started spawning at the same time, in the middle of October. This indicates initiation of reproductive activity in the field in August, coincident with the descent into deep waters. Potential cues for the untimely spawning of females collected in spring and ‘unnatural’ feeding in fall experiments are discussed. Their large size, robustness and combination of different types of diapause in their life cycle make C. hyperboreus a good model organism to study diapause control mechanisms.     

Social organization and sexual pattern in the Mediterranean parrotfish Sparisoma cretense (Teleostei: Scaridae)

We examined the social organization and reproductive pattern of a population of Sparisoma cretense L. at Lampedusa Island (Italy). During the breeding season (July to September) individuals occur either in territorial or in non-territorial groups, which quantitatively differ with respect to use of space, sex-ratio and sexual activity. Territorial groups consist of one male plus one to three females, whereas in non-territorial groups as many as 54 fish share a common area. Among non-territorial groups, variations, in both sex-ratio and behavior, suggest they could represent either feeding aggregations or reproductive aggregations. Spawning, always in pairs, occurs daily in a short period of time before dusk and has been observed only in territorial groups. Group spawning has never been observed, but another alternative mating tactic, streaking on pair spawning, was recorded. In the non-breeding season fish do not aggregate in organized social units. Histological examination of gonads showed that adults are larger than 12 cm total length. Females have an asynchronous ovary, typical of species spawning several times during the breeding season. Males show secondary testes, indicating that their gonads develop ovaries as juveniles, which are later redifferentiated into functional testes. Histological and demographic data seem to indicate that, as in other species of this genus, prematurational sex-change occurs. The sexual pattern appears to be essentially gonochoristic, but the potential for sex-change is not excluded. Received: 5 January 1999 / Accepted: 22 June 1999     

Factors affecting the spawning period of sardine in two highly oligotrophic Seas

Ovarian histology and weight dynamics of reproductive and somatic tissues were used to investigate seasonality of spawning and factors affecting reproductive period in two E Mediterranean sardine, Sardina pilchardus, populations (central Aegean and Ionian Seas), between September 1999 and May 2001. Despite similarities in the general spawning pattern of the two populations, i.e. protracted spawning season during the colder months of the year, reproductive period in the Ionian was shorter and lagged behind the Aegean by 2–3 months. In both Seas, reproductive period was influenced by body size as smaller females tended to have both shorter and delayed spawning season. Whereas hepatosomatic index (HSI) was consistently higher in reproductively active females during the whole spawning period, seasonality of spawning did not match variations of HSI. In both Seas fluctuations of HSI matched the spring burst of primary productivity and were followed by fluctuations in somatic condition and mesenteric fat by a 2 months’ lag. Somatic condition and reproductive activity displayed inverse seasonal patterns, implying that egg production in sardine basically relies on visceral and muscular fat deposits, accumulated during the summer growing season. Reliance of egg production on past energetic reserves suggests that sardine is a capital breeder, which is a rather efficient strategy in such oligotrophic habitats as the E Mediterranean, where winter spawning is accompanied by a particular decline in adult preying fields.     

Distribution of marine predator hotspots explained by persistent areas of prey

Investigations of distributional and density patterns of marine predators often reveal areas where high abundances of one or many species overlap in space and time (‘biological hotspots’); however, mechanisms underlying hotspot formation are often unclear, leading to difficulties determining spatial and temporal boundaries of protected areas. On the northeast Newfoundland coast, I previously described annually persistent aggregations of a key forage fish species, capelin (Mallotus villosus): (1) two pre- and post-spawning staging areas in deep (>150 m) bathymetric channels, (2) a cluster of four persistently used demersal spawning sites (17–40 m), and (3) a coastal migratory route (<50 m). Through at-sea surveys repeated over 8 years (2000–2003, 2007, and 2009–2011), I show that the majority of predator hotspots identified were spatially associated with (i.e., within 10 km) these persistent capelin areas for breeding seabirds (common murre: 85.2 ± 4.6 %; northern gannet: 66.9 ± 6.6 %), overwintering seabirds (great and sooty shearwaters: 88.0 ± 6.9 %), and baleen whales (humpback, minke, and fin whales: 86.8 ± 8.6 %). Most predator hotspots were closer to the spawning (3.8–14.0 km) relative to the staging areas (13.1–27.6 km), especially for murres and shearwaters. Interspecific differences were attributed to variation in maximum dive depths and dietary preferences. Predators only aggregated within the spawning area, while capelin were spawning, suggesting that interannual variation in association with predator and capelin hotspots was attributed to variation in survey timing relative to capelin spawning. As these areas of persistent capelin are bound by static bathymetric and large-scale oceanographic features and can be delimited in time based on the capelin spawning period, they may be important candidate areas for protection.     

Reproductive success of nesting male longear sunfish (Lepomis megalotis peltastes)

Summary Although a few male longear sunfish nest solitarily, most territorial males excavate their nest in dense aggregations. The importance of sexual selection in the evolution of this breeding system was evaluated by 1) examining the influence of certain male and nest characteristics on spawning success and 2) by comparing the success of social and solitary nesters. Among group nesters, females spawned preferentially with males nesting early within a spawning period and occupying central nests. Male size and nest diameter were negatively correlated with nesting day and hence spawning success. However, female discrimination using these traits directly could not be demonstrated. The reproductive success of social and solitary males was compared by counting the larvae in their nests several days after spawning. Successful males (with larvae) were more likely than males without larvae to be encountered later in the breeding season and to nest in small groups or solitarily. Spawning period (of which there were 5 or 6 in a season) was significantly correlated with larval abundance in the nest, while male size was not. Social and solitary males were equally successful, but aggregations may nonetheless result from sexual selection: males unlikely to attract females may nest around more attractive males to steal fertilizations from them. High spawning synchrony may prevent attractive males from renesting elsewhere once other nesters aggregate around them.     

Reef coral reproduction in the eastern Pacific: Costa Rica,Panamá, and the Galápagos Islands (Ecuador). VI. Agariciidae, <Emphasis Type="Italic">Pavona clavus</Emphasis>

The reproductive ecology of the zooxanthellate reef coral Pavona clavus was investigated at several sites in Costa Rica, Panamá, and the Galápagos Islands (Ecuador) over the period 1985–2009. Pavona clavus displayed stable gonochorism as only five hermaphrodites were found in 590 samples. At four of five locations, sex ratios were skewed toward female dominance; however, at Saboga Island (Panamá) male colonies predominated. In Panamá, sexual maturity was observed in an estimated eight-year-old female colony, and several colonies of 10–20 years of age demonstrated gametogenesis. Sexual activity was observed at all study sites, but gamete development occurred in only 14–31% of colonies sampled sporadically. Seasonality of gametogenic activity occurred predominantly during the warm/wet season, June to August, at mainland sites (Caño Island, Costa Rica, and Gulfs of Chiriquí and Panamá, Panamá). This pattern was repeated in the Galápagos Islands, but mainly from March to May when seasonally high sea temperatures and rainfall prevailed there. Histological sampling and field observations indicated that spawning was centered around the full moon, most frequently on lunar day 17, and near sunset (1,800 h). Mean fecundity (mature ova cm^?2 live tissue) estimates were significantly different for two sites and ranged from ~1,780 (Saboga Island, Gulf of Panamá, seasonally upwelling) to ~4,280 (Uva Is, Gulf of Chiriquí, non-upwelling). Assuming three annual spawning events colony^?1 (August, September, October), extrapolation of minimum and maximum fecundities yield 5,340 and 12,840 ova cm^?2 year^?1. Seasonal, lunar, and diel spawning patterns in nine zooxanthellate species at Uva Island indicate asynchronous coral community spawning.     

Reproduction of<Emphasis Type="Italic"> Ophiactis resiliens</Emphasis> (Echinodermata: Ophiuroidea) in New South Wales with observations on recruitment

Reproduction of the ophiuroid Ophiactis resiliens Lyman 1879, a common species in the shallow waters around Australia, was examined over 1 year in two populations near Sydney, New South Wales. Gametogenesis was documented by histological examination of the gonads. Vitellogenesis in females and spermatocyte proliferation in males started in February and March. O. resiliens had an annual spawning period from May to September/October with peak gamete release from May to July. Thereafter, spawning occurred in some specimens through November. Gravid gonads were present for approximately 2 months longer in O. resiliens from Clovelly Bay than in those from Little Bay. At both sites spawning was episodic and gametogenesis continued through most of the spawning season. Most specimens (50–100%) collected from November to March had indeterminate/recovery stage gonads, the sex of which, could not be determined. The timing of gametogenic renewal during these months varied among individuals. O. resiliens has a 3-month planktonic stage and the presence of juveniles, 0.5 –1.5 mm disk diameter, in the coralline algal turf at Little Bay from February to May, suggests that settlement occurs in summer and autumn at this site. In contrast, juveniles were rarely encountered in coralline turf at Clovelly.     

Reproductive periodicity of the scleractinian coral Lophelia pertusa from the Trondheim Fjord, Norway

Between 2002 and 2008, samples of the cold-water scleractinian coral Lophelia pertusa were collected from the Trondheim Fjord in Norway to examine reproductive periodicity. Collections were made from three locations: Tautra, (63°35.36′N, 10°31.23′E at 40–70 m), Stokkbergneset (63°28.18′N, 09°54.73′E at 110–500 m), and Røberg (63°28.88′N, 09°59.50′E at 250 m). Populations of L. pertusa from the Trondheim Fjord initiated oogenesis in January and spawning occurred from late January to early March the following year. Gametogenic cycles of the female L. pertusa samples overlapped by approximately 2 months, with oogonia visible in January, but this was not evident in the males. This paper provides the most complete gametogenic cycle to date and spawning observations for this important structure-forming species. The results from fjord populations are compared with published and preliminary data from other regions and are discussed in the context of regional differences in physical and biological variables, particularly food supply. Differences in gametogenic cycles within a single species provide a rare opportunity (especially in deep-sea species) to examine potential drivers of reproduction.     

Seed choice by rodents: learning or inheritance?

Learning plays a central role in animal life, and it has received special attention in the context of foraging. In this study, we have tested whether learning operates in seed choices by rodents using the Algerian mouse (Mus spretus) and Holm oak (Quercus ilex) acorns as a model. At the laboratory, those rodents captured in the field during the acorn fall period (experienced individuals) rejected weevil-infested acorns, presumably because of their lower energetic value. By contrast, rodents born in captivity and reared without any contact with acorns (naïves) predated weevil-infested acorns at similar rates than sound ones. After exposing naïves to infested and sound acorns during 15 days, they rejected infested acorns as the experienced individuals. In the field, predation on weevil-infested acorns was lower than on sound ones. Predation rates on infested acorns were lowest at the end of the acorn fall season, whereas predation rates of sound acorns increased along the same period. This might be explained by the improved ability to reject infested acorns because of the accumulated experience acquired by the initially naïve rodents along the acorn fall season. We show that learning shapes strongly seed choices by rodents, and it may be advantageous over inherited behaviors in variable unpredictable situations, such as acorn infestation rates that vary strongly between years and trees. We consider that the role of learning has to be taken into account in future studies on seed predation by rodents.     

Parental care and the cost of reproduction in a Mediterranean fish

Summary Symphodus tinca is a common near-shore Mediterranean labrid fish in which females may sometimes spawn their eggs over hundreds of square meters, or alternatively spawn into well-defined algal nests. Eggs spawned in either manner are fertilized, but widely scattered eggs receive no parental care, whereas eggs spawned into nests are usually guarded by the male until they hatch. Here, I report weight changes of individual marked fish that engaged in a variety of different reproductive behaviors during three breeding seasons. Males gained weight at 0.15% per day outside the spawning season, and added 29–78% to their overall body weight between reproductive seasons, even following substantive weight losses in a spawning season (up to 20% among nesting males). Nesting and nest-guarding males lost an average of 0.32% and 0.41% of their body weight per day in 1986 and 1987. This cost is four times greater than reproduction for nonnesting males, which registered a 0.03% daily weight gain. Actively spawning females lost 0.06% of their body weight daily during the spawning season. While long-term growth rates did not appear to be substantially affected by reproduction in either sex or by parental care in males, present work does not exclude the possibility that such long-term effects may exist.     

Spawning migration and returning behavior of white-streaked grouper Epinephelus ongus determined by acoustic telemetry

White-streaked grouper (Epinephelus ongus) is an important fishery target that forms fish spawning aggregations (FSAs) at specific spawning grounds. The aims of the present study were to investigate migration behavior and returning behavior in terms of FSA using acoustic telemetry. Among the 30 specimens tracked, three types of movement pattern were observed: type 1, high site fidelity at the release area before the spawning period, migration to the spawning ground during the spawning period and return to the release area just after the spawning period (17 specimens); type 2, high site fidelity at the release area, disappearance from the area during the spawning period but was not detected at the spawning ground and return to the release area (8 specimens); and type 3, high site fidelity at the release area was observed before, during and after the spawning period (5 specimens). For the 17 specimens that were categorized into type 1, the dates of departure from their release area and the dates of return to the release area of males were, respectively, significantly earlier and later than those of females. The duration between the departure date and the return date (“duration away”) of males was significantly longer than that of females. The duration away tended to be positively related to the condition factor. All 25 specimens that were categorized as type 1 and type 2 showed returning behaviors to the release area.     

Gametogenesis and spawning periodicity in the fan worm <Emphasis Type="Italic">Sabellastarte spectabilis</Emphasis> (Polychaeta: Sabellidae)

The sabellid polychaete Sabellastarte spectabilis (Grube 1878) was collected at approximately monthly intervals from January 2002 to December 2003 from intertidal and subtidal reefs near the Hawaii Institute of Marine Biology in Kane’ohe Bay, Hawaii, USA (21°N, 157°W). Gametogenesis and spawning periodicity were investigated using histological techniques and induction of spawning trials. Worms were characterized into four discrete reproductive stages based on histological evidence: (1) No evidence of reproductive activity in the coelom (sex cannot be determined), (2) Only coelomocytes present in the coelom (sex cannot be determined), (3) Some gametes present in the coelom (sex can be determined) and (4) Coelom densely packed with gametes (sex can be determined). The small hermaphroditic portion of the population was not used in this study. Stage 4 worms were present over an extended period of time (females, March–December and males, March–November) indicating a potentially broad reproductive season. No correlation between day length and maturation stages in S. spectabilis was detected. However, the statistical model Y = ([394.26 × X] − [7.793 × X ²]) − 4960.781 where Y the % frequency of Stage 4 worms and X the mean monthly water temperature explained 44% of the variation between water temperature and % frequency of Stage 4 worms. Maturation appeared to coincide with water temperatures of 24–25°C (March–September) after which there is a reduction in the % frequency of stage 4 individuals. Induction of spawning trials conducted between May and January showed the month of October with a significantly higher percent success than any other month investigated. According to all available information (e.g., natural spawning in water tables, histological data, induction of spawning trials, correlation of maturation stages with observed changes in average monthly water temperature.), there is an apparent peak in reproductive activity (spawning) within a broad maturational season, which may be influenced by water temperature.     

Changes in the spatial distribution of spawning activity by north-east Atlantic mackerel in warming seas: 1977–2010

Migratory species with a broad geographic range, such as north-east Atlantic mackerel, may be amongst the fauna most able to respond to warming seas, typically with a poleward shift in range. Habitat heterogeneity could, however, produce more complex patterns than a simple polewards translation in distribution. We tested for changes in the central location and spatial spread of mackerel spawning over a 33-year period. Spatial statistics [centre of gravity (CoG) of egg production, spatial variance, and degree of anisotropy] were used to summarise interannual changes in the spawning locations of the western spawning stock of north-east Atlantic mackerel (NEA-WSC) using data from the ICES triennial egg survey. A northwards shift in CoG of egg production estimates was observed, related to both an expansion in the distribution in survey effort and warming waters of the north-east Atlantic. Sea surface temperature (SST) had a significant positive association with the observed northward movement of NEA-WSC mackerel, equivalent to a displacement of 37.7 km °C^?1 (based on spring mean SST for the region). The spatial distribution of spawning around the CoG also changed significantly with SST, with a less elongated spatial spread in warm years. An increase in the proportion of spawning over the Porcupine Bank demonstrated how habitat interacts with positional shifts to affect how north-east Atlantic mackerel are distributed around the centre of their spawning range.     

Seasonal cycle of gonadal development and serum levels of vitellogenin of the red porgy, Pagrus pagrus (Teleostei: Sparidae)

Histological examination of gonads of female and male red porgy, Pagrus pagrus, reared in captivity, was carried out in order to describe the main gonadal changes related to gametogenesis and the seasonal changes of environmental factors. The gonadosomatic index (GSI) and the concentration of serum vitellogenin (VTG) were also determined. The frequency distribution of gonad development stages and the GSI and vitellogenin concentration during the annual cycle indicated the separation of the female and male reproductive cycles into three main periods. The autumn period when gametogenesis begins (October-November), the period of exogenous vitellogenesis (December-March) or spermiation (December-March), and the spawning season (March-May). The spawning period coincided with an increase in temperature (15-19°C) and daylength. Serum levels of vitellogenin rose significantly in January, reached a peak at the beginning of the spawning period (March, 405.5 µg ml^-1) and remained high until the end of the spawning period (May).     

The role of fecundity regulation and abortive maturation in the reproductive strategy of Norwegian spring-spawning herring (<Emphasis Type="Italic">Clupea harengus</Emphasis>)

This study investigates the reproductive strategy, an important component in the estimation of stock reproductive potential, in Norwegian spring-spawning (NSS) herring (Clupea harengus), an iteroparous, extreme capital spawner, through the estimation of fecundity over a period of 3 years including two complete maturation cycles and three spawning seasons. NSS herring have an ‘optimistic’ strategy, with almost all adult herring caught in August being in the vitellogenic stage of ovary development, despite overwintering energy levels not being determined at this time. Fecundity in the summer, i.e., more than half a year before spawning in spring (February–April), was also much higher than could be supported by an individual’s concurrent energy levels. Consequently, fecundity was later reduced through atresia with the majority of this occurring before overwintering. The total reduction and the length of the time period in which the reduction took place appeared to vary between years. During the spawning season, atresia was mostly prevalent in small first-time spawners <180 g and several individuals aborted ovary development at this time. Final fecundity varied between years with a difference of up to 18% and was linked to annual variations in condition. In conclusion, this extensive field study has demonstrated that each individual herring can display a suite of size-specific reproductive tactics to fine-tune oocyte production in response to fluctuating levels of planktonic prey.     

Sardine (Sardina pilchardus) spawning seasonality in European waters of the northeast Atlantic

Egg data from ichthyoplankton monitoring sites in the western English Channel (1988–2003) and northern Spain (1990–2000) and macroscopic maturity data from biological samples of purse seine landings in western and southern Iberia (1980–2004) are used to describe the spawning seasonality of sardine (Sardina pilchardus) in European waters of the northeast Atlantic using generalised additive models. The fitted models reveal a double peak in spawning activity during early summer and autumn in the western Channel, a wider spring peak off northern Spain and a broad winter season in the western and southern Iberian Peninsula. At all sites, a high probability of spawning activity was observed over at least 3 months of the year, with the duration of the season increasing with both decreasing latitude and increasing fish size. Off western and southern Iberia there are indications that the spawning season has been of longer duration in recent years for all size classes (reaching in some cases 8 months of the year for large fish). These patterns are in general agreement with existing literature and theoretical expectations of sardine spawning being driven locally by the seasonal cycle of water temperature, assuming preferences for spawning at 14 –15°C and avoidance for temperatures below 12°C and above 16°C. Regional quotient plots indicated that spawning tolerance to higher temperatures increases progressively with decreasing latitude. Despite the weak evidence for geographical differences in temperature tolerance that may have some genetic origin, the degree of spatio-temporal overlap in sardine-spawning activity within Atlantic European waters is unlikely to promote any reproductive isolation in that area.     

Strong responsiveness to noise interference in an anuran from the southern temperate forest

Animals adopt different strategies to communicate by means of sound in noisy environments. Some animals increase, while others decrease, their vocal activity in the presence of interference. Anuran amphibians from diverse latitudes exhibit both kinds of responses. Recent studies have shown that males of Batrachyla taeniata and Batrachyla antartandica from the temperate austral forest do not call in response to the presentation of advertisement calls of sympatric congeneric species, but their responsiveness to other kinds of interference has not been tested. To explore the diversity in responsiveness to acoustic intrusion in a single species, we exposed males of B. taeniata to prolonged prerecorded natural abiotic noises of wind, creek, and rain and to a band-pass noise centered at 2,000 Hz, at 67 dB sound pressure level (SPL). The subjects drastically increased their call rate when exposed to all four sounds. Frogs also responded by augmenting their vocal activity to exposures of band-pass noise at increasing intensities (55–79 dB SPL). The increase in vocal activity in response to noise is strong relative to those of other anurans from the temperate forest studied previously under similar exposures. These results reveal a remarkable activation of vocal response to acoustic interference of continuous abiotic noise, which would allow compensating for limitations in the active communication space under background sounds. This strategy contrasts with the decrease in vocal output amid interference from heterospecific signals reported formerly for this frog, a tactic that would restrict energy expenditure to relevant acoustic competition with conspecifics.