Major Spawning Period Research Articles

Individual-based modeling of shelled pteropods

Shelled pteropods are cosmopolitan, free-swimming organisms of biogeochemical and commercial importance. They are widely used as sentinel species for the overall response of marine ecosystems to environmental stressors associated with climate change and changes in ocean chemistry. However, currently we are unable to project the effects of climate change on shelled pteropods at the population level, due to the missing spatio-temporal characterization of the response of pteropods to environmental stressors, and the limited information on the pteropod life history and life-cycle. In this study, we implement a shelled pteropod Individual-Based Model (IBM), i.e. we simulate a pteropod population as a set of discrete individuals over several generations, life-stages (eggs, larvae, juveniles and adults) and as a function of temperature, food availability, and aragonite saturation state. The model is able to provide an abundance signal that is consistent with the abundance signal measured in the temperate region. In addition, the modeled life-stage progression matches the reported size spectrum across the year, with two major spawning periods in spring and fall, and maturation in March and September. Furthermore, our IBM correctly predicts the abundance maxima of younger, smaller and potentially more susceptible life-stages in spring and winter. Thus, our model provides a tool for advancing our understanding of the response of pteropod populations to future environmental changes.

Age, growth and reproduction of the golden grey mullet, Chelon auratus (Risso, 1810) in the Golden Horn Estuary, Istanbul

AbstractAge, growth and reproduction biology of the golden grey mullet, Chelon auratus (Risso, 1810) have been studied in the Istanbul Golden Horn area. Fish length ranged from 13.4–46.8 cm, and age from 1–10 years, respectively. The sex ratio (female:male) was 1:1.08. The length-weight relationship was estimated as W = 0.0127L2.89, W = 0.0099L2.97 and W = 0.0156L2.82 for both sexes combined, females and males, respectively. The von Bertalanffy growth equation parameters were: L∞ = 57.52 cm, K = 0.1 year−1, t0 = −2.24 year for pooled data. The gonadosomatic index (GSI) values indicated the major spawning period was between August and November, and the minor spawning peak between March and April. The highest GSI values were observed in September. The length and age of sexual maturity were estimated as 26.2 cm and 4 years for males and 24.1 cm and 3 years for females.

Impact Assessment of Twenty-Two Days Fishing Ban in the Major Spawning Grounds of Tenualosa ilisha (Hamilton, 1822) on its Spawning Success in Bangladesh

This study was conducted to evaluate the impact of twenty-two days fishing ban from October 22-November 02, 2016 on the spawning success of Hilsa in the major spawning grounds of Hilsa. Fishing ban during the spawning season have substantial role in the successful reproduction of Hilsa found from the present study. Among all the Hilsa captured in and around the spawning grounds of Hilsa, male and female were estimated to make up 34% and 64% respectively of the total catch, suggesting a male to female sex ratio of about 1:1.94. In the year 2016 during the major spawning period in the major spawning grounds 43.93% spent Hilsa was found and calculated egg production was 628291 kg and the estimated Jatka production was 39,268 crore which were found to be much higher than the previous years. Increased production of Hilsa eggs and Jatka indicates a positive impact of twenty-two days fishing ban in the spawning season. Percentages of gravid and oozing Hilsa were also found higher compared to previous fishing ban periods. In the spawning grounds, relatively higher amount of spent Hilsa and Jatka were observed whereas fewer spent Hilsa and Jatka were found in the adjacent areas of spawning grounds. Besides Jatka, spawn and fries of other fish species were also found in higher quantity in and around the spawning areas of Hilsa than previous years which indicates fishing ban might have positive impacts on successful breeding and maintenance of biodiversity of other fish species. Overall, twenty-two days fishing ban was found to be very effective for successful spawning of Hilsa.

Reef-scale failure of coral settlement following typhoon disturbance and macroalgal bloom in Palau, Western Pacific

Factors affecting coral recruitment are critical in influencing the scope and rate of reef recovery after disturbance. In December 2012, super-typhoon Bopha caused immense damage to the eastern reefs of Palau, resulting in near complete loss of coral cover. Within weeks following the typhoon, an ephemeral monospecific bloom of the foliose red macroalga Liagora (up to 40 % cover in February 2013) was recorded at impacted reefs with moderate wave exposure. Conversely, impacted and un-impacted reefs in areas of low wave exposure remained Liagora free. To quantify the effect of this ephemeral macroalgal bloom on coral recruitment, we installed settlement tiles during the major spawning period (March–April 2013) at forereefs with and without Liagora. Reefs (n = 3) with Liagora (13–24 % cover in April) experienced an almost complete failure of settlement, with only two individual corals recorded on settlement tiles (n = 90). This settlement failure was unexpected, as tiles were situated adjacent to, and not within Liagora canopies. In contrast, settlement was significantly higher on reefs that lacked macroalgae (n = 3), ranging from an average of 0.5–2.5 and 2.7–18.9 individuals 25 cm−2 per top- and under-sided tile, respectively. Reefs with and without Liagora were in close proximity (≤8 km), and hydrodynamic models predicted that larval supply did not limit coral settlement among sites. While some differences in the community composition on the tiles were observed among sites, settlement substrate availability also did not limit coral settlement. Generalised linear mixed effects models indicated that while no settlement substrate explained more than 10 % of the variability in coral settlement, coral cover positively accounted for 26 %, and the cover of Liagora on reefs negatively accounted for more than 50 % of the observed variation. Combined, our results indicate that the typhoon induced ephemeral macroalgal bloom resulted in a reef-scale failure of coral settlement.

Spatial variation in the annual reproductive cycle of Turbo (Batillus) cornutus (Gastropoda: Trochidae) at Jeju Island, Korea

The annual reproductive cycle of the top shell Turbo cornutus from Jeju Island was investigated in two populations using histology. In the northern population, gametogenesis commenced in January as the surface water temperature reached 14 °C, while in the southern population gametogenesis began a month earlier, as the water temperature remained at 17 °C. Ripe top shells first appeared in June and spawning continued from June to October when water temperatures were between 20 and 24 °C. Histology indicated that the spawning period of the southern population was a month earlier and lasted longer (June–October) than in the northern population (July–September). The percentage gonad area of animals in the southern population in March and April was significantly higher than in the northern population (p < 0.05), suggesting that the gonads of the southern population matured earlier. The observed earlier maturation and the subsequent spawning of the top shells from the south coast of Jeju Island could be associated with the warmer water temperature and more favorable environmental conditions. The major spawning period of top shells observed in this study from July to September suggested that the currently implemented period of the fishing closure from June to August needs to be re-evaluated to protect more spawning adults in late summer.

Reproductive cycle in an imposex-affected population of Olivancillaria deshayesiana (Gastropoda: Olividae) from Mar del Plata, Argentina

AB Aquatic Biology Contact the journal Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AB 15:111-119 (2012) - DOI: https://doi.org/10.3354/ab00407 Reproductive cycle in an imposex-affected population of Olivancillaria deshayesiana (Gastropoda: Olividae) from Mar del Plata, Argentina Valeria Teso1,*, Florencia Arrighetti2, Pablo E. Penchaszadeh1 1CONICET—Museo Argentino de Ciencias Naturales, Av. Angel Gallardo 470, Lab. 57, C1405DJR Buenos Aires, Argentina 2CONICET—Laboratorio de Biología de Invertebrados Marinos, DBBE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina *Email: valeriateso@gmail.com ABSTRACT: Olivancillaria deshayesiana (Gastropoda: Olividae) is distributed from Ilha Grande (Rio de Janeiro, Brazil) to Necochea (Buenos Aires, Argentina). Apart from some descriptions of the embryonic development and the egg capsules, little is known about the reproduction and ecology of this species. In this 2 yr study (October 2005 to September 2007), the reproductive cycle of O. deshayesiana was examined in a population highly affected by imposex, from the Mar del Plata coast, Argentina. Males exhibited seasonal reproductive activity, with a major spawning period from September to January (spring to early summer) for the 2 yr, which coincided with an increase in seawater temperature and photoperiod. In contrast, females were mature and capable of spawning year round, with a major spawning period from September to January (spring to early summer), simultaneous with the major spawning period of males. KEY WORDS: Imposex · Mar del Plata · Olivancillaria · Olividae · Reproduction Full text in pdf format PreviousNextCite this article as: Teso V, Arrighetti F, Penchaszadeh PE (2012) Reproductive cycle in an imposex-affected population of Olivancillaria deshayesiana (Gastropoda: Olividae) from Mar del Plata, Argentina. Aquat Biol 15:111-119. https://doi.org/10.3354/ab00407 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AB Vol. 15, No. 2. Online publication date: May 15, 2012 Print ISSN: 1864-7782; Online ISSN: 1864-7790 Copyright © 2012 Inter-Research.

Aspects of Reproduction and Sexuality in the Black-spot Tuskfish, Choerodon schoenleinii

The annual reproductive cycle and sexuality of Choerodon schoenleinii were studied histologically. The major spawning period persisted from February until May, spawning of individuals occurring almost every day during the most active period, being March and April. Relationships between TL and both Fecundity and batch fecundity were obtained. C. schoenleinii mature as females at about 24cm TL and exhibit protogynous hermaphroditism with monandric sexuality. Sex transition occurred from 40-64 cm TL, all fish larger than 65 cm TL being males. C. schoenleinii is closely sexually dichromatic, the body color changing from an initial greenish-yellow phase (female) to a terminal blue phase (male), in almost complete accordance with the sex transition.

Annual reproductive cycle of the oyster, Saccostrea kegaki (Torigoe & Inaba 1981) on the southern coast of Jeju island, Korea

Gametogenesis of the oyster Saccostrea kegaki (Torigoe & Inaba, 1981) on the southern coast of Jeju (Cheju) Island, Korea was assessed monthly (March 2001 to February 2002). Gametogenesis in females and males commenced in April when the water temperature reached 16.5°C. Ripe gametes were observed from June to September in both sexes. Partially spawned oysters were evident from July to October when the water temperature ranged 24.6–26.7°C. Most oysters collected in July and August exhibited partially empty follicles with large eggs (>35 μm in diameter), suggesting that these two months are the major spawning periods. From November to March, most female oysters were in resting stage exhibiting no gametes in the follicles. In contrast, spawning or spent male oysters could be seen during November and January. Monthly mean oocyte diameters ranged from 10.3 ± 1.7 μm in April (early developing stage) to 36.9 ± 5.7 μm in August (ripe stage) and the mature oocyte was comparatively smaller than the size found in other oysters. The relatively slow rate of gametogenesis observed in S. kegaki off southern Jeju could be in part explained by low level of food in the water column rather than by water temperature.

Gametogenesis, spawning and fecundity of Platygyra daedalea (Scleractinia) on equatorial reefs in Kenya

The reproductive ecology of the hermaphroditic broadcast spawning scleractinian reef coral Platygyra daedalea was studied on lagoonal reefs in Kenya. While single annual gametogenic cycles occurred in 84% of colonies, biannual gametogenic cycles were recorded in 16% of colonies and these patterns occurred in two morphotypes. In colonies with a single annual cycle, oogenesis occurred for 6–7 months from September to March and spermatogenesis for 5 months from November to March. In biannually spawning colonies, oogenic cycles overlapped for at least 2 months prior to gamete release. The major spawning period occurred in February and March, with minor spawning also occurring in August–October in biannually spawning colonies. Reproductive effort was lower during the minor winter compared to the major summer spawning, with fewer colonies reproducing (12.5–19.2%), not all mesenteries producing oocytes (32.5%) and less than half of the mesenteries with mature oocytes had associated spermaries (48.1%).

Temporal variation in habitat use by nekton in a subtropical estuarine system

Utilisation by fish of different estuarine habitats is known to vary at many different temporal scales, however no study to date has examined how utilisation varies at all the relevant times scales simultaneously. Here, we compare the utilisation by fish of sandy, intertidal foreshore habitats in a subtropical estuary at four temporal scales: between major spawning periods (spring/summer and winter), among months within spawning periods, between the full and new moon each month, and between night and day within those lunar phases. Comparisons of assemblage composition, abundance of individuals and of fish in seven different ‘ecological guilds’ were used to identify the temporal scales at which fish varied their use of unvegetated sandy habitats in the lower Noosa Estuary, Queensland, Australia. Fish assemblages were sampled with a seine net at three different regions. The most numerically dominant species caught were southern herring ( Herklotsichthys castelnaui: Clupeidae), sand whiting ( Sillago ciliata: Sillaginidae), weeping toadfish ( Torquigener pleurogramma: Tetraodontidae), and silver biddy ( Gerres subfasciatus: Gerreidae). Considerable variation at a range of temporal scales from short term (day versus night) to longer term (spawning periods) was detected for all but one of the variables examined. The clearest patterns were observed for diurnal effects, where generally abundance was greater at night than during the day. There were also strong lunar effects, although there were no consistent patterns between full moon and new moon periods. Significant differences among months within spawning periods were more common than differences between the actual spawning periods. The results clearly indicate that utilisation of sandy, unvegetated estuarine habitats is very dynamic and highly variable in space and time.

GAMETOGENESIS IN THE NON-NATIVE GREEN MUSSEL, BRACHIDONTES EXUSTUS, IN TAMPA BAY, FLORIDA

Histologic examination of the nonnative green mussel, Perna viridis, and the native scorched mussel, Brachidontes exustus, at three locations in Tampa Bay, Florida, indicated that cycles of gametogenesis and spawning were similar between species. Major spawning periods occurred in the spring (April) in conjunction with increasing water temperature and the fall (September to November) as the water temperature was declining. Over the summer, both species appeared to undergo varying levels of redevelopment, partial spawning and resorption of oocytes. Gametogenesis was limited over the winter. Differences between populations in levels of gametogenic activity and the timing of the fall spawn were most likely related to differences in salinity and available food at the three sites. A higher fecundity (caused by the faster growth rate and greater maximum size of P. viridis) may result in displacement of native bivalves in Tampa Bay, including B. exustus.

Características histológicas del ciclo reproductivo de Euvola ziczac (Linnaeu) (Pectinidae, Bivalvia) del litoral sur-sudeste del Brasil

Scallops were collected from beds at 30 to 40 m depth on the south-southern inner continental shelf of Brazil for histological gonadal characterization of the reproductive cycle. This hermaphroditic scallop was an important shellfish resource during 70-80 decade, with maximal annual landings of 8,845 tons, but now is depleted. Results shows that reproduction is continuous, with two major spawning periods, the first during end of summer and throughout autumn, and the second during winter and beginning of spring. A characteristic phenomenon of oocyte atresia, with maximal incidences in September is described. This phenomenon, followed by the mature oocyte resorption and new oocyte proliferation and maturation, was related to the lack of spawning stimulation. A semi-annual thermal cycle on the bottom water due to the South Atlantic Central Water intrusion seems to be the principal reproductive cycle controller. Fluctuations in landings registered since the beginning of the fishery may be partly related to oceanographic variations.

Reproductive strategies of three deep-water benthopelagic fishes from the northeast Atlantic Ocean

The reproductive strategies of three benthopelagic species of deep-water fish from the northeast Atlantic were studied: Helicolenus dactylopterus (245–800 m depth), Coryphaenoides rupestris (400–1500 m depth) and Alepocephalus bairdii (650–1700 m depth). The reproductive strategies and fecundity of the females of the three species were studied over a 2-year sampling period (December 1995–December 1997). H. dactylopterus reproduced from March to June and oocyte development within the population was synchronous. Annual fecundity was indeterminate, but batch fecundity ranged from 1212 to 20 504 oocytes per female. Reproduction in C. rupestris extended from February to November with a maximum from May to November. Oocyte development within the population was not synchronous. Annual fecundity was indeterminate, but batch fecundity was estimated to be between 4078 and 68 780 oocytes per female. The precise period of reproduction for A. bairdii could not be determined; however, mature fish were found throughout the year with a major spawning period from January to April. Oocyte development within the population was not synchronous. Annual fecundity was indeterminate, but batch fecundity was estimated at 458–7049 oocytes per female. There was a trend for an increase in the duration of the reproductive period and a decrease in synchronicity of maturation with increasing depth. A long spawning period and asynchrony in maturation may be partially explained by the lack of marked cyclic environmental factors in the deep sea.

Seasonal Variation of Ichthyoplankton in a Western Caribbean Bay System

The plankton of Bahia de la Ascension was sampled monthly, from August 1990 to July 1991, to ascertain ichthyoplankton composition, abundance, and seasonality. These data were used to assess the inferred function of the bay as spawning and nursery grounds. Fifty-one families, 66 genera, and 53 species of fish embryos and larvae were identified. Engraulidae, Clupeidae, Labrisomidae, Callionymidae, Gerreidae, and Gobiidae comprised 81.5% of the larvae captured: the remaining 18.5% included several coral reef fish families. Greatest mean fish egg densities were recorded between December and April, 341–246 per 100 m3, suggesting a major spawning period. The monthly mean density of total fish embryos and larvae showed two peaks: one in late dry season (June), dominated by newly hatched engraulid, and a second (December) during the cold-front season with high densities of preflexion labrisomid and engraulid embryos. When labrisomid and engraulid embryos and larvae were excluded, densities peaked in the rainy season (July to October). Gerreidae and Callionymidae were significantly more abundant in the rainy season, while Labrisomidae and Gobiidae in the cold-front season. The highest embryos and larvae richness was observed in August during the rainy season with mean value significatively greater than those from cold-front and dry seasons. The occurrence of high egg densities and the wide range of embryos and larva stages are evidences that Bahia de la Ascension is a regionally important spawning and nursery ground for marine fish. Because this study covered partially the marine ecosystem of Bahia de la Ascension using convential gear, we suggest to conduct further research for have a full understanding of the importance of this bay for fish recruitment.

Observations on the Reproductive Ecology of Pirate Perch Aphredoderus sayanus

ABSTRACT The pirate perch (Aphredoderus sayanus) is common throughout its range; however, little is known about its reproductive ecology. Reports of spawning periods range from January to April, but it is unclear whether the pirate perch is a nest spawner or a branchial brooder. Results of this study indicated the major spawning period for pirate perch in the Atchafalaya River Basin, Louisiana, is February through March (12.6—22.8 °C). Larval pirate perch were collected in limnetic areas at 3.6-mm total length and were absent at 14-mm total length. It appears that adult pirate perch are not branchial brooders but release their adhesive eggs over leaf litter and woody debris.

Intraspecific variation in gametogenesis in two populations of the Chilean molluscan bivalve, Argopecten purpuratus (Lamarck)

An increased understanding of the general biology of Argopecten purpuratus (Lamarck) is necessary to produce successfully high quality larvae in hatcheries and to collect enough spat in situ for growth on long lines. In the present study, the reproductive cycles of two populations of A. purpuratus were examined, the Mejillones and Rinconada scallop banks, from 1989 to 1993. Calculation of the gonosomatic index and a complementary histological study of the gonad revealed differences between the two populations in their reproductive cycle as well as in the quantity of gamete emissions. The Rinconada population has a major spawning period occuring at the end of the year and lasting about three months. Minor spawnings also occur in early July to late September. In Mejillones individuals, only one major period of gametogenesis and spawning occurs. Gametogenesis begins in January and spawning occurs between February and March. This is followed by a period of quiescence lasting four to five weeks. These results suggest that the Mejillones individuals are a more appropriate source of genitors to be used for conditioning in hatcheries. Existing data on biometrics, particularly the dimensions of the adductor muscle, as well as enzyme polymorphism, suggest that the Rinconada population would be a more appropriate source of genitors to be used in future aquaculture attempts.

東京湾におけるトリガイの成長，成熟と産卵期

Growth, maturation and spawning season of Fulvia mutica (Reeve) were examined using shell length frequency analysis, and seasonal changes in percentages occurrence of the mature individuals.Size-frequency analysis of shell length showed that the mode of 0-age group was less than 20mm in August, and grew over 60mm by next April. Thereafter, however, one year age group showed a very slow growth. It seems that most of the cockle can not survive till age two. The von Bertalanffy growth curve of the cockle was determined as SLt=96.42[1-exp{-0.0818(t-0.2007)}], where SLt is shell length in mm at age t in month.Both the condition factor and meat weight index were high in March and low after June. Percentage occurrence of mature individuals showed a peak from April to July, and decreased sharply afterward. The shell length of the mature individuals were ranged from 50mm to 55mm, which were supposed to be just one year in age. Analysis showed that spawning season of the cockle in Tokyo Bay lasted from April to July with the major spawning period of May and June.

Gonadal Maturation in the Cobia, Rachycentron canadum, from the Northcentral Gulf of Mexico

Gonadal maturation of cobia, Rachycentron canadum, was evaluated by examining 508 specimens from its recreational fishery. Specimens were collected off southeast Louisiana to northwest Florida by hook-and-line during February through October 1987-1991. Fork lengths (FL) of these fish ranged from 580-1,530 mm, with corresponding weights of 2.0-43.5 kg. The female:male ratio was 1:0.37. Using a combination of oocyte sizefrequency and histological assessment of many of the fish, we determined that females were ripe from May through September, with atretic oocytes occurring in some fish from July through October. Degenerating hydrated oocytes in July and October and the presence of resting ovaries in July suggest two major spawning periods; however, monthly gonosomatic indices peaking in May, followed by a steady decline, do not support that finding. Ovaries were placed into undeveloped, early developing, mid-developing , or late developing categories based upon oocyte size-frequency distributions. Developing ovaries had two or three modes of oocytes larger than 30 pm. Batch fecundity was estimated to be 2 . 6 ~ 1 0 ~ to 1.91~108 oocytes, depending on the size of fish/ovaries. The smallest female with oocytes exhibiting vitellogenesis was 834 mm FL. This fish was 2 years old based its otolith evaluation. The smallestmale with an abundance of spermatozoa in its testes was 640 mm FL and 1 year old based on otolith evaluation; smaller males were not examined. Females larger than 840 mm FL had vitellogenic oocytes in March and April. A few fish still had vitellogenic oocytes in early October, but none did by late October. When Gilson’s fluid was used to assess ovarian tissue, the fresh weight of the tissue was reduced by 20% after being stored for 3 months. The diameter of oocytes shrunk about 25% in Gilson’s fluid which was 11% less than those fixed in formalin, embedded in paraffin, and sectioned. Tissue sections from specific individuals, each demonstrating a variety of different developmental stages, were similar regardless of whether they were obtained from the anterior, middle, or posterior portion of either ovary.

Settlement of mussels Mytilus galloprovincialis on an exposed rocky shore in Ria de Vigo, NW Spain

The mussel farming industry of the Galician re· gion (NW Spain) requires that 60 to 70% of its seed supply is taken from rocky shore areas. However there are almost no quantitative data for a recruitme nt and settlement pattern. In the Ria de Vigo a continuous settlement throughout the year with a major settlement season fr om May to September was fo und, reflecting the presence of spawning mussels through· out the year and the occurrence of a maJor spawning period during the spring. The observed settlement pattern indicates the direct settlement of larvae from the plankton onto the adult beds and an immigration of mussels previously settled on other substrates. This pattern could be a response to the ecological and environmental conditions that occurred on the Galician rocky shores, but could also be a differential charac· teristic between Mytilus edulis and M. galloprovincialis.

東京湾船橋地先におけるアサリの生殖周期

Seasonal gonadal changes were investigated by observation of oocyte diameter and histological examination in samples of Manila clam Ruditapes philippinarum collected from Funabashi waters in Tokyo Bay from May 1988 to September 1991. Gametogenesis was observed from January to November and gonadal maturation was bimodal, similar to southern areas of the Japanese Pacific coast, with peak periods occurring from April to June and from August to October. Gametogenesis in summer was less synchronous between individuals than in winter-spring and was characterized by the prolonged holding of a large number of matured gametes together with partial resorption and new growth of young gametes. Two annual peak periods in the condition factor, which conincided with gonadal maturation, were evident from April to May and August to September. The major spawning period of Manila clam in Funabashi waters was supposed to occur in spring, since gonadal maturation was highly synchronized and the condition factor reached its annual maximal value in this season.