Peak Of Reproductive Activity Research Articles

The reproductive biology of Ellochelon vaigiensis from the Vietnamese Mekong Delta.

The Squaretail mullet, Ellochelon vaigiensis, is a commercial fish species distributed throughout the Indo-Pacific region. This species tolerates wide variations in salinity, having been reported from both freshwater and marine habitats. Although economically significant, there is little information on its reproduction, especially in the Vietnamese Mekong Delta (VMD), where it is heavily extracted. Our study elucidates the breeding pattern, seasonality, first length at maturity, as well as potential and relative fecundity of this species. Fish specimens were collected by trawl nets from November 2020 to October 2021 at four estuarine sites within the VMD. We found this species to be a synchronous spawner, with peaks in reproductive activity from June to September. In the populations we surveyed, there was significant dominance of males (1.26:1.00) based on 942 fish samples (526 males and 416 females). The length at 50% maturity for females was significantly higher than for males at all sites and ranged from 10.6 to 19.3 cm. The diameter of the eggs examined for this species exhibited slight variation, from 0.43 to 0.54 mm. The potential fecundity ranged from 246,254 ± 35,878 to 411,970 ± 54,370 eggs, corresponding to female length and weight of 26.7-32.6 cm and 102.97-234.19 g, respectively. Relative fecundity values were highest at Thanh Phu, Ben Tre (6388 ± 605 eggs), and Dong Hai, Bac Lieu (6461 ± 637 eggs), followed by Tran De, Soc Trang (4729 ± 408), and were found to be lowest at Duyen Hai, Tra Vinh (3117 ± 223 eggs). Information on reproductive behavior in this species has far-reaching impacts on sustainable extractions, stock conservation, and aquaculture.

Influence of environmental factors on reproduction of the invasive Gulf toadfish Opsanus beta (Teleostei: Batrachoididae) in a subtropical estuary

A hallmark of biological invasion is the rapid reproduction of invasive species. However, we still do not have an adequate understanding of how fluctuations in environmental factors affect the reproduction of invasive species, particularly in estuarine habitats. In this study, we evaluated the reproduction of the Gulf toadfish Opsanus beta and its relationships with temperature and rainfall in the Paranaguá estuary, a subtropical region in southern Brazil. This species was likely introduced into the Brazilian ecosystems through the discharge of ballast water. Since invasion, which was first reported in port areas, the species has rapidly spread along the Brazilian coast line. We collected specimens monthly from October 2011 to September 2012 and from October 2019 to September 2020, to give us insight into the seasonal and temporal changes in the reproduction of this species. We found that O. beta population uses the estuary throughout its life cycle, including during spawning. Females and males spawned throughout almost the entire sampling period and spawning was specified as partially. Peak reproductive activity occurred in periods of lower temperature and was also related to rain. The length of first maturation in females (10cm) was considered early, indicating reproductive activity in smaller individuals. Our results demonstrate that the reproductive strategy used by the invasive species supports its ability to successfully colonize new environments.

Temperature-dependent reproduction of Spodoptera eridania: developing an oviposition model for a novel invasive species.

Temperature plays a critical role in the development and reproductive process of insects, therefore understanding how insects respond to temperature is vital for comprehending and predicting their population dynamics, particularly when it comes to agricultural pests. Spodoptera eridania Stoll is a polyphagous pest that has recently expanded its distribution beyond its native range. In this study, we assessed the impact of temperature on the reproduction of S. eridania and used the obtained data to develop an oviposition model that could be used to predict egg-laying behavior under field conditions. The reproductive parameters were evaluated at temperatures of 15, 20, 25, 28, and 32 °C. Temperature had a significant impact on the reproductive parameters examined. Overall, as temperature increased, the pre-oviposition period, oviposition period, and longevity decreased. Total fecundity exhibited a bell-shaped response to temperature, with peak egg-laying observed at 20 and 25 °C. In line with the experimental data, our model predicted higher rates of oviposition between 20 and 26 °C, thus reinforcing that this temperature range may represent the optimal conditions for the reproduction of S. eridania. The findings from our study provide a significant contribution to the understanding of the ecology of an important agricultural pest. The information generated can have practical applications in developing control strategies by enabling the aligning of the timing of control measures with peaks of reproductive activity. © 2023 Society of Chemical Industry.

Activity Patterns, Sex Ratio, and Social Organization of the Bare-Faced Curassow (Crax fasciolata) in the Northern Pantanal, Brazil

Among Neotropical cracids (Galliformes), many taxa are declining rapidly in population size and facing local extinction. However, in the Brazilian Pantanal, several species occur sympatrically and in abundant numbers to allow for long-term studies. Therefore, the study was intended to collect data and statistically evaluate the life history patterns of Bare-faced Curassow (Crax fasciolata), a high-conservation-priority species. Additionally, the effect of applying commonly used independence filters on camera trap data was evaluated. The study was conducted in the SESC Pantanal, Baía das Pedras, Mato Grosso, Brazil, a private protected area of approximately 4200 ha. Between July 2015 and December 2017 (4768 sampling days), 37 sampling locations were monitored with camera traps placed in a regular grid with a spacing of 1 km. Crax fasciolata was detected at 26 (70.27%) of them, with 357 independent captures (554 individuals). Capture success differed among the four seasonal periods, being highest during the receding and lowest during the high-water period. The seasonal difference was more pronounced in the savanna, with significantly lower activity during the rising period and higher activity during the receding period, while it was more uniform in forest-dominated areas. Groups with offspring were more active during the period of receding water, indicating the peak of reproductive activity in the months before. The daily activity of the species followed a bimodal pattern, with peaks between 06:00 and 07:00 and 16:00 and 17:00. Daily activity rhythms were similar when compared between seasonal periods, sexes, and adults with or without offspring and differed between two habitats (more homogeneous in the forest). The mean detected group size was 1.55 ± 0.81 SD, with four animals exhibiting the largest observed aggregation. Larger unisexual aggregations of adults were not observed. The offspring sex ratio was significantly female-skewed at 0.51:1.00, while the adult sex ratio was considered equal at 1.05:1.00 (male:female). The use of different independence filters did not alter the BFC general activity pattern estimates. Cracids can be considered important bioindicators of habitat quality. The results of this study outline the importance of the Pantanal as a stronghold for this species and the privately protected areas with low anthropogenic activity as highly beneficial to its populations.

Testicular Melatonin and Its Pathway in Roe Deer Bucks (Capreolus capreolus) during Pre- and Post-Rut Periods: Correlation with Testicular Involution.

Roe deer are seasonal breeders with a complete yearly testicular cycle. The peak in reproductive activity is recorded during summer, the rutting period, with the highest levels of androgens and testicular weight. Melatonin plays a pivotal role in seasonal breeders by stimulating the hypothalamus-pituitary-gonads axis and acting locally; in different species, its synthesis within testes has been reported. The aim of this study was to evaluate the physiological melatonin pattern within roe deer testes by comparing data obtained from animals sampled during pre- and post-rut periods. Melatonin was quantified in testicular parenchyma, along with the genetic expression of enzymes involved in its local synthesis (AANAT and ASMT) and function (UCP1). Melatonin receptors, MT1-2, were quantified both at protein and gene expression levels. Finally, to assess changes in reproductive hormonal profiles, testicular dehydroepiandrosterone (DHEA) was quantified and used for a correlation analysis. Melatonin and AANAT were detected in all samples, without significant differences between pre- and post-rut periods. Despite DHEA levels confirming testicular involution during the post-rut period, no correlations appeared between such involution and melatonin pathways. This study represents the first report regarding melatonin synthesis in roe deer testes, opening the way for future prospective studies in the physiology of this species.

New data on the reproductive activity of Mugil cephalus L. from Algerian coast

The aim of this study was to provide additional insight into the reproductive activity of Mugil cephalus L. along the Algerian coast. All specimens were sampled from local commercial fisheries from January 2017 to January 2018. The reproductive period and the size at first sexual maturity were determined. Our results show that the males reach sexual maturity at smaller lengths (28.8 cm) than females (34.5 cm) and that sex ratio is female-skewed (63% vs 37%). The peak of reproductive activity took place from August to October, and spawning took place in November. Sexual rest occurred during subsequent months with a tendency of fattening from December to April. The seasonal evolution of the gonadosomatic index suggests that M. cephalus breeds from August to October. The analysis of the evolution of hepatosomatic index and Fulton’s K apparently reveal no contribution of liver and muscle tissues to the reproduction activity of this species. The high fecundity estimated could be considered a reproductive strategy to maximise the survival of juveniles.

Timing of reproduction and association with environmental factors in female free-roaming dogs in southern India

Annual peaks in reproductive activity have been identified in multiple domestic dog populations. However, there is little evidence to describe how these peaks may be associated with environmental factors such as daylength, which plays a well-established role in breeding patterns of seasonally-reproductive species.Data were collected 2016–2020 during 7,743 and 4,681 neuter surgeries on adult female unowned free-roaming dogs in veterinary clinics in Goa and Tamil Nadu respectively. Temperature, precipitation, relative humidity, and daylength data were gathered for time periods preceding the neuter surgery that may have influenced the likelihood of pregnancy (potential influence periods). A multivariable generalised additive model was used to assess the relationship between these factors and pregnancy.The prevalence of pregnancy varied by month in both locations indicating seasonality of reproduction in these groups. The annual pattern was more distinct in Goa with a peak in pregnancies between September and December. In Goa, decreasing daylength was associated with a higher probability of pregnancy (p = 0.040). Decreasing temperature was associated with decreasing probability of pregnancy in the Nilgiris (p = 0.034). Bitches had a median of 6 foetuses, with no evidence of seasonal variation.Environmental factors were associated with patterns of pregnancy in free-roaming dogs, however statistically-significant factors varied by geographical location. Establishing local seasonal patterns of breeding in free-roaming dogs and assessing their relationship with environmental influences is recommended to facilitate effective and efficient population management strategies, which aim to reduce conflict between human and free-roaming dog populations.

A synopsis of the ecology of Protura (Arthropoda: Hexapoda)

This publication reviews the literature on the ecology of Protura. Current knowledge is scarce, fragmentary and scattered among papers which do not all strictly deal with ecology or soil arthropods communities. Therefore all available information is summarized in order to better understand the ecology of these arthropods. The density of Protura ranges from hundreds to thousands of individuals per m2. Their aggregate distribution is probably related to food (fungal hyphae) availability and quality, and to the production of aggregation pheromones. Protura tend to form species assemblages characterizing different habitats. Their populations often show an unbalanced sex ratio in favour of females, suggesting that a single male can fertilize several females, perhaps via spermatophores. For some species only females have been collected, which suggests the possibility of parthenogenesis. Our analysis of the available information on phenology and population dynamics of Protura points toward annual cycles with one, two or more peaks of reproductive activity.

Food selectivity and reproductive biology of small indigenous fish Indian river shad, Gudusia chapra (Hamilton, 1822) in a large tropical reservoir.

Assessment of life history strategies of economically important small indigenous fishes (SIF) which are rich in nutritive values is essential and imperative to artisanal and subsistence small-scale inland fisheries of Indian tropical reservoirs. The present investigation aims to estimate the food selectivity in juveniles and adults, reproductive traits such as sexual maturity, gonadosomatic index, ova diameter, and fecundity of Gudusia chapra from a large impounded ecosystem of India. A total of 668 (Juvenile 129, adult 539) specimens, 37 to 142mm standard length and 0.89-25.68g body weight were collected during October 2014-September 2015. The qualitative estimation of the stomach contents revealed herbi-omnivorous feeding behavior of fish. The mean relative gut length (mRGL) of the species was 1.557 ± 0.024 in juveniles and 1.154 ± 0.012 in adults. The sex ratio was 1:1.30 with dominance of females in the population though insignificant. The total length at which 50% individual attain maturity (TL50) was estimated as 80.50mmbased on the logistic curve. The absolute fecundity of the individuals ranged from 749 to15044, and ova diameter ranged from 0.10-2.00mm. The gonadal indices (GSI, MGSI, and DI) indicated that spawning extended throughout the year with peak reproductive activity in October, March-April, and July (mean absolute fecundity ranged from 4000 to 6000). The present study characterized biological and reproductive traits of G. chapra from a large reservoir ecosystem and demonstrated a new trend of reproductive pattern which will serve as benchmark data for future assessment and management planning of this species in impounded waters. The study also suggested some specific management measures for sustainable exploitation and conservation of small indigenous species.

Reproductive cycle, sexual maturity and longevity of Odontophrynus americanus (Anura: Odontophrynidae) in South Brazil

AbstractStudies on the reproductive biology and age of amphibians provide primary information about the life history and population demographic parameters of species. Here, we describe the reproductive cycle, size–fecundity relationships, reproductive effort, sexual dimorphism and sexual maturity of Odontophrynus americanus, the flood frog, from South Brazil. A total of 96 individuals were analysed. The reproductive cycles of males and females were described through morphoanatomical analysis of testis and ovary. Age at onset of sexual maturity and estimated longevity were determined by skeletochronology. Individuals of O. americanus presented a potentially continuous reproductive cycle with a peak of reproductive activity in the warmer months. Females presented a higher reproductive investment than males. Sexual maturity was reached at around one year of age for both sexes while longevity differed between the sexes, with females living up to six years and males up to ten years. No evidence of sexual size dimorphism was found. This study is among the few that have assessed age at sexual maturity and longevity in a Neotropical anuran. Basic aspects of life history are of paramount importance because they allow comparisons and test of hypotheses to be made, which can help to build generalizations about the evolutionary meaning of ecological strategies.

Nearly year-round reproduction among individuals of a Japanese freshwater threespine stickleback population

The freshwater threespine stickleback (Gasterosteus aculeatus) shows tremendous interpopulation variation in a variety of phenotypic traits, including reproductive characteristics. We investigated individual-level reproductive patterns in the freshwater Ono population in Japan, which occurs nearly at the southern global range limit for this species. Although G. aculeatus populations generally only reproduce in spring and/or summer, we directly observed tagged individuals in semi-natural enclosures and found that both males and females reproduced almost the year long. We observed two peaks in reproductive activity, spring to early summer and autumn to early winter, at both the population and individual levels. Thus, we found unique features in the timing and duration of reproduction of this freshwater population, which inhabits spring-fed areas with constant year-round water temperatures.

Timing of the reproductive cycle of waved whelk, Buccinum undatum, on the U.S. Mid-Atlantic Bight

Development of the unmanaged waved whelk (Buccinum undatum) fishery on the Mid-Atlantic continental shelf of the United States has initiated investigation into fisheries-related biological and population attributes of the species in this region. Maturation and reproduction timing vary by location for this species and are likely linked to bottom water temperature. This study examined the seasonal fluctuations in relevant body metrics and gonadosomatic index in relation to bottom temperature to assess the timing of the reproductive cycle of the B. undatum population in the southern-most extent of this species’ range in the Atlantic. To characterize variation over the maturation schedule, nine locations in the Mid-Atlantic Bight (MAB) were sampled five times between January 2017 and September 2017. Maturity was assessed macroscopically, with morphological methods, and via gonadosomatic indices. Male behavioral maturity estimates, based on a penis length to shell length index (PL50), were compared to estimates made using other methods for assessing maturity to test the efficacy of this commonly used ratio. Mature whelk were found in all months and peak reproductive activity was observed in spring and early summer. This timing suggests that ideal sampling to visually identify maturity to estimate size of maturity would be late winter or early spring. Unique oceanographic dynamics in the MAB, such as strong seasonal stratification results in large changes in annual bottom temperature which appears to be closely linked to the reproductive cycle in this region. Our data suggest that B. undatum in the MAB experience spawning and development at ~ 7–8 °C; temperatures warmer than Canadian populations and cooler than some UK conspecifics. To our knowledge, this is the first study to document the annual reproductive cycle of waved whelk in the United States.

Ecology of Italian Protura

The ecology of Protura in Italy (including Corsica) is tentatively described according to original and bibliographical data. Protura are quite common but very rarely abundant: their mean density in soil samples collected in Liguria (NW Italy) was estimated to be 372 /m² (s.d. 657 – max. 2790 /m² in a Holm oak forest). Information from the analyses of habitat and/or elevation of 3448 specimens from 269 collections and 4071 specimens from 295 collections identified to species and genus level, respectively, enabled us to outline Protura assemblages for eight different macro-habitats. The unbalanced sex ratio in favour of females observed in 12 of the dominant species of Acerentomata suggests that (based also on the sperm types known in Protura) a single male can fertilize several females through spermatophores. For one species (Proturentomon minimum) only females were collected, which may suggest the possibility of parthenogenesis in some Protura. An analysis of the phenology and population dynamics of the five dominant species, showed annual cycles with one (Acerentomon microrhinus) or more (A. gallicum, A. italicum, A. maius and Eosentomon transitorium) peaks of reproductive activity. Other ecological remarks (e.g. about the relationship between the amplitude of latitudinal/altitudinal distribution and the ecological distribution of Protura in Italy) are discussed.

Coral reproduction at Hall Bank, a high latitude coral assemblage in Western Australia

Research on coral reproduction has increased dramatically in recent times; however, there remain significant regions, in particular high latitude reefs, where research is limited. For example, the reproductive biology of species in the coral assemblage at Hall Bank, a high latitude site (32 degrees S) in southern Western Australia, remain unknown. Here, reproductive traits and the likely time of spawning for 12 of the approximately 16 species that occur at Hall Bank were established using histology between March 2009 and March 2011 at 7 discrete time points. Peak reproductive activity most likely occurs in February, as 7 of the 10 species sampled in this month had colonies with mature gametes. The sexuality, mode of larval development and transmission of symbionts were, as expected, consistent with previous work. The reproductive biology of the corals at Hall Bank is consistent with other regions of the Indo-Pacific, supporting the hypo thesis that reproductive traits such as sexuality and mode of larval development are evolutionarily conserved and do not vary biogeographically.

Comportements reproducteurs du labre oiseau Gomphosus caeruleus dans un récif de l’île de la Réunion : mode de reproduction, facteurs environnementaux et alternance des stratégies reproductrices

The green birdmouth wrasse Gomphosus caeruleus is present all year round on the coral reefs of Reunion Island (Indian Ocean). A group of individuals was followed on one of these reefs with the objective of studying the reproduction mode of the species, the influence of environmental factors, and social behaviors on the control of reproduction. Our observations revealed that G. caeruleus is, like many Labridae, a protogynous hermaphrodite species, probably diandric, that the reproduction of G. caeruleus is, like in other reef fish species, influenced by the lunar cycle with a peak of reproductive activity during waxing gibbous phase, and that G. caeruleus displays social behavior leading to alternating haremic mating system on a single territory and lek-like mating systems without aggressions between males. These observations enhanced our knowledge of the reproduction of Labridae and reef species.

Possible Effect of Global Climate Change onCaretta caretta(Testudines, Cheloniidae) Nesting Ecology at Guanahacabibes Peninsula, Cuba

Abstract Changing climate is affecting life all over the world. The loggerhead turtle (Caretta caretta) is one of the most vulnerable turtle species to climate change, particularly with regard to sex determination being affected by high temperatures in most nesting areas, such as the Cuban archipelago. As yet, species information is scarce for the Cuban archipelago as a whole. This study provides information about loggerheads in order to determine the possible effects of climate change on this species, especially in Guanahacabibes. We monitored 10 beaches along the southernmost coast of the Guanahacabibes Peninsula for 18 yrs (1998–2015), from May to September of each year, to determine nesting activity and density. Females were measured and tagged and the remigration interval was determined. Temporal variation was reflected in apparent peaks in reproductive activity on a biennial cycle. We found intraseasonal variation with the highest nesting activity in June, with a 15% increase in nesting activity in ...

Reproductive biology of the migratory freshwater fish Salminus brasiliensis (Cuvier, 1816) in the Cuiabá River basin, Brazil

This study provides information on the reproductive biology of the dorado Salminus brasiliensis from the Cuiabá River basin, through determinating life history trajectories (length at first maturity, fecundity and spawning type) and the reproductive period, thus establishing the relationships between biotic factors and rainfall and river levels that might act as potential triggers for maturation and spawning. Salminus brasiliensis is a migratory species of great commercial and ecological importance. Individuals were collected monthly from August 2013 to July 2014 in the Cuiabá River. Analyses were performed based on biometric data and the gonads. Females attained greater lengths than males in the Cuiabá River basin, and with a significant difference in the sex ratio in favor of females. Peak reproductive activity occurred in November and December and was related to rainfall. Reproduction was seasonal, with spawning and reproductive potential correlating positively with the length and mass of the gonads of mature females. Average length at first maturity for females was estimated at 55 cm. A regular (annual) monitoring programme of essential biological variables to support a trend analysis over years (not just a snapshot study, as this one) is strongly recommended in order to give advice for the proper fishing policies in the region, as without regular basic data on the population dynamics, management is not possible.

Reproductive biology ofPseudoplatystoma corruscans(Spix and Agassiz, 1829) andPseudoplatystoma reticulatum(Eigenmann and Eigenmann, 1889), two species of fisheries importance in the Cuiabá River Basin, Brazil

The aim of this study was to compare the reproductive processes of two large catfishes, Pseudoplatystoma corruscans and Pseudoplatystoma reticulatum, from the Cuiabá River Basin. The reproductive process were assessed to: (i) characterizing the population structure and sex ratio; (ii) determining the reproductive period; (iii) estimating and quantify the nutritional status and energy reserves and their relationships with reproductive stages; and (iv) estimating the body length at first gonad maturation (TL50). Individuals were sampled monthly from July 2006 to February 2008 using gill nets, seine nets, hooks, casting nets and trotlines. In addition, 294 individuals were obtained from the artisanal fishery in the city of Cuiabá, Mato Grosso state, Brazil. Total lengths were greater for females for both species, with no significant difference in the sex ratio; growth was considered isometric, except for P. corruscans males. Peak reproductive activity was in December and January. Differences in the hepatosomatic index (HSI) in P. corruscans depended on the gender. In P. reticulatum the HSI did not differ between sexes or among developmental stages. For P. corruscans, the estimated mean total length at first maturity (TL50) was 62.92 cm, and for P. reticulatum 57.84 cm. Action to ensure the protection of the fish stocks should consider their reproduction processes, which are important for the equilibrium of these populations in the Cuiabá River, as well as for fisheries management.

Low Temperature Brooding of Olympia Oysters (Ostrea lurida) in Northern Puget Sound

Olympia oysters (Ostrea lurida) traditionally played important ecological, economic, and cultural roles as the only oyster native to the west coast of North America. Yet overfishing, pollution, and the cultivation of nonnative oysters have driven many historic beds toward or into extinction. Restoration efforts have increased recently in an attempt to reestablish this important ecosystem engineer. In 2012, the Swinomish Indian Tribal Community began a small-scale Olympia oyster enhancement effort in two tidal lagoons with the intention of eventually establishing self-sustaining populations. To properly time future expansion efforts with peak reproductive activity, brooding status was quantified from oyster populations within both lagoons throughout the spring and summer of 2015. Brooding data were compared with water temperature and salinity. Results from this study clearly indicate that northern Puget Sound oysters located in tidal lagoons are capable of brooding at 10.5°C, two degrees colder than has been reported in the literature. Oysters in one lagoon brooded for almost an entire month before the known critical daily minimum water temperature threshold of 12.5°C was reached. These results suggest possible local adaptation or habitat-specific reproductive maturation, and are relevant for Olympia oyster restoration and expansion efforts.

The benthic community of an intertidal mud flat in the Gulf of Nicoya, Costa Rica. Description of the community

Structural changes of the soft-bottom community of a tropical intertidal mud flat (more than 30% silt + clay) in the Gulf of Nicoya, Costa Rica, were evaluated from February, 1984 through February, 1985. Core samples (core area: 17.7 cm2) were collected, at semi-monthly intervals, within a 484 m 2 area and to a depth of 15 cm into the sediment. Samples were preserved in 10% buffered formalin in sea water stained with Rose Bengal. Organisms retained on a 500 mieron mesh sieve were considered as macrofauna.A total of 92 species of macro-invertebrates and the gobiid fish, Gobionellus sagitulla (Gunther) were collected. The community was numerically dominated by deposit feeders. The ostracod, Cyprideis pacifica Hartmann and an undescribed cumacean (Bodotriinae) were the most common organisms found, representing 4 3.4% of the total. The polychaetes, Mediomastus californiensis Hartman, Paraprionospio pinnata (Ehlers), and Lumbrineris tetraura (Schmarda) accounted for 19.2% of the total. An unidentified flatworm (Turbellaria) represented 8.3% of the total number of individuals. Mean density of macro fauna (± 1 SO) was 13,827 ± 10, 1 85 individuals per m2. Diversity (H’) ranged from 1.75 to 3.36 per date (28 cores) and equitability (Evenness) ranged from 0.48 to 0.87.Cluster, principal components, and multiple discriminant analyses revealed a seasonal pattern of the community (dry and rainy seasons). Most species appear to reproduce throughout the year. Peaks of reproductive activity, however, were detected for a group of species.In addition to biological and physical disturbance, spatial and temporal variability of water currents and water characteristics, coupled with an inferred preponderance of planktotrophic larvae, are considered as the main factors promoting changes in community structure.The importance of deposit feeding invertebrates, the types of feeding modes and habitat utilization, and the existence of seasonal patterns, make this community similar to certain temperate zone counterparts. To emphasize these similarities, and for convenience in referring to this assemblage of species, the community is named after a surface deposit-feeding spionid polychaete, a burrowing pinnotherid crab, and a scavenger snail, as the Paraprionospio pinnata - Pinnixa valerii - Nassarius luteostoma community.