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1.
本文根据海湾扇贝的肥满度、肉柱百分数、性腺指数及消化脓指数等指标的周年变化，并结合性腺的组织切片来确定其繁殖期。结果表明，海湾扇贝南移后的繁殖期是从每年的10月下旬开始的，直到翌年5月下旬，其中4月为繁殖盛期。繁殖期间，扇贝的性腺分批成熟，分批排放，并有消退与恢复的现象。同时，海湾扇贝引进中国北方海区并南移福建后，其繁殖规律与原产地（美国大西洋沿岸）的繁殖期有很大的不同。 相似文献
2.
The sea cucumber Holothuria scabra is a widely distributed and economically important species that has been harvested in Kenya for decades. No previous studies have been carried out on the reproduction of this species in Kenya. Standard gonad index methods were used to analyze reproductive patterns of individuals collected monthly in 1998–1999, 2000–2001 and 2006–2007. Morphological characteristics, gonad tubule lengths and fecundity were also measured. Mean monthly gonad indices were significantly correlated between males and females indicating synchronous gonad development between the sexes. Gonad indices showed a biannual pattern that was consistent in all three years with a minor spawning event occurring between August and September and a major spawning event between November and December. The pattern of gonad growth showed significant variability between years and between months. Temporal changes in gonad growth correlated significantly with gonad tubule length and absolute fecundity. Monthly gonad indices also correlated significantly with monthly measurements of air temperature and light suggesting a possible role for both factors in timing gametogenesis and spawning. There was a shift in sex ratio from unity in the 1998–1999 and 2000–2001 samples to significantly more males in the 2006–2007 samples, as well as a significant reduction in mean sizes (body wall weight) and reproductive output (gonad index) which suggests that the reproductive success of this species is potentially negatively affected by fishing. 相似文献
3.
The reproductive cycle and environmental cues that regulate gonad production in Asterina stellifera were studied from April 2009 to April 2011 in a rocky subtidal habitat at the southernmost limit of its distribution (Mar del Plata, Argentina). The geographic variation in reproductive traits between latitudinal range limits was analyzed. The gonadal and pyloric caeca weight varied with sea star size and time in both sexes. Despite a previous study which suggested the absence of recruitment in a 4 year period, our data of the same period demonstrated that spawning happens from early spring to early summer. The gonad and pyloric caeca weight did not show an inverse relationship, this suggested that there is no dependence on energy transfer between the organs and that the bat star presented a good nutritional state. Seawater temperature appears to be the variable explaining gonad proliferation at the range limits of A. stellifera distribution. Furthermore, differences in sex ratio, oocyte production, oogenesis duration and capability of energy transformation into ova were found between range limits. 相似文献
4.
In the brackish water Baltic Sea turbot spawn at ~ 6–9 psu along the coast and on offshore banks in ICES SD 24–29, with salinity influencing the reproductive success. The potential fecundity (the stock of vitellogenic oocytes in the pre-spawning ovary), egg size (diameter and dry weight of artificially fertilized 1-day-old eggs) and gonad dry weight were assessed for fish sampled in SD 25 and SD 28. Multiple regression analysis identified somatic weight, or total length in combination with Fulton's condition factor, as main predictors of fecundity and gonad dry weight with stage of maturity (oocyte packing density or leading cohort) as an additional predictor. For egg size, somatic weight was identified as main predictor while otolith weight (proxy for age) was an additional predictor. Univariate analysis using GLM revealed significantly higher fecundity and gonad dry weight for turbot from SD 28 (3378–3474 oocytes/g somatic weight) compared to those from SD 25 (2343 oocytes/g somatic weight), with no difference in egg size (1.05 ± 0.03 mm diameter and 46.8 ± 6.5 μg dry weight; mean ± sd). The difference in egg production matched egg survival probabilities in relation to salinity conditions suggesting selection for higher fecundity as a consequence of poorer reproductive success at lower salinities. This supports the hypothesis of higher size-specific fecundity towards the limit of the distribution of a species as an adaptation to harsher environmental conditions and lower offspring survival probabilities. Within SD 28 comparisons were made between two major fishing areas targeting spawning aggregations and a marine protected area without fishing. The outcome was inconclusive and is discussed with respect to potential fishery induced effects, effects of the salinity gradient, effects of specific year-classes, and effects of maturation status of sampled fish. 相似文献
5.
Reproductive cycles of the Pacific oyster Crassostrea gigas (Thunberg) from the Marlborough Sounds, New Zealand, were followed between June 1998 and January 2000. Histological examination of the gonad confirms an annual cycle with a winter inactive period followed by rapid gonad development and a single short spawning period. The population gonad index correlated with seawater temperature and changes in tissue dry weight, condition index, and biochemical components. In winter, few individuals with early gametogenic stages were present and rapid development of primary oocytes (diam. 11 μm) occurred during spring (September‐November). The developmental rate and the diameter of mature oocytes (37 μm) was similar for the 1998 and 1999 seasons. For a standard 110‐mm‐length oyster, maximal tissue body weight and condition index were recorded in December. Rapid weight loss in January was length dependent and was attributed to spawning. Temperature was the environmental variable which best correlated with the timing of gametogenesis. Food availability (phytoplankton biomass) may have been responsible for inter‐annual variations. The biochemical composition (% glycogen, lipid, protein) of separated gonad and somatic tissues were variable seasonally and annually. Gametogenesis (oocyte diameter) was associated with increased gonad protein and glycogen and a decrease in lipid concentrations. These changes are similar to those in Pacific oyster populations from other parts of the world. 相似文献
6.
为了解烟台多棘海盘车种群个体大小分布及繁殖特征，自2010年5月至12月及2015年3月到5月，在烟台近海对该种群分别进行逐月采样调查。利用性腺指数(GI)和幽门盲囊指数(PCI)以及解剖组织学方法预测其产卵周期。结果表明：在所有的采样月份中，体长大于143mm的个体与体长小于42mm的个体在种群中均同时存在；在5-8月期间，种群结构特征以体长小于55mm的个体为主。同时该海域不同站点的采样月份中均有小个体存在，说明种群的产卵周期存在延后现象或者由于食物短缺造成了海星生长缓慢。腕长可以很好的用来衡量还行身体湿重。性腺在2010年5月-9月发育相对缓慢但在十月份迅速到达峰值20.95，之后明显下降，表明其产卵期从10月份持续至11月份。2015年3月-5月也发现了同样的现象，表明该种群自3月-5月存在另一个产卵期，且通过对卵的组织学分析也进一步证实该产卵期的存在。性腺指数和幽门盲囊指数呈负相关关系。由于食物来源短缺，烟台近海海星种群的繁殖特征极有可能受到当地近海扇贝养殖的影响。 相似文献
7.
Response of excised gill tissue from the New Zealand scallop Pecten novaezelandiae to suspended silt
Peter M. Stevens 《新西兰海洋与淡水研究杂志》2013,47(4):605-614
The role of turbidity in scallop mortality was investigated for two size classes of Pecten novaezelandiae (70 ± 2 mm and 20 ± 1 mm shell height), by using the “crawl” velocity of excised pieces of gill tissue as an indicator of the response to suspended silt. The crawl velocity of 3 × 5 mm pieces of gill tissue was measured in six different silt concentrations (0.025, 0.05, 0.1, 0.2, 0.3. 0.5% silt, by dry weight) and two size classes (< 10 μm and 10–30 um) of silt. Results of the study indicate that juvenile (20 mm shell height) scallops may be less tolerant of suspended silt than larger (70 mm shell height) scallops and that both size classes may be less tolerant of fine (< 10 μm) silt/clay sized particles than coarse (10–30 μm) particles. These conclusions are supported in part by data from the mortality of whole 20 mm scallops exposed to two size classes (< 10 μm and 10–30 μm) and three concentrations (0.05, 0.3, 0.6%, by dry weight) of silt. Increasing concentrations and decreasing particle size of the suspended silt resulted in reduced gill piece crawl velocity and an increase in the mortality rate of the whole scallops. These results suggest controls on human‐induced disturbance of bottom sediments, such as bottom trawling and dredging, may benefit any further scallop bed enhancement programmes by the avoidance of deterioration in water quality and mechanical damage to scallop spat. 相似文献
8.
The impact of overfishing and El Niño on the condition factor and reproductive success of Peruvian hake, Merluccius gayi peruanus 总被引：1，自引：1，他引：0
Michael Balln Claudia Wosnitza-Mendo Renato Guevara-Carrasco Arnaud Bertrand 《Progress in Oceanography》2008,79(2-4):300
In this study we examine physiological responses of Peruvian hake (Merluccius gayi peruanus) to changes in their population structure and physical environment during the period 1971–2004. In particular, we assess the relative investment of energy in growth and/or reproduction of small (20–35 cm) and large (35–50 cm) hake. We calculated the (i) condition (Fulton’s K), (ii) gonad and (iii) gut fullness indices for 42,761 female hakes sampled from commercial landings; these indices indicate fish somatic, reproductive and feeding condition, respectively. Using Generalized Additive Models we then examined potential relationships between these indices and sea surface temperature anomalies and date. Drastic energy exhaustion and a decrease in female hake fecundity were observed during El Niño events. The long-term trend showed a general increase in condition factor and a decrease in gonad index for large hake between 1971 and 2004. Small hake exhibited a different trend with an increase in reproductive activity, which was accompanied by an earlier maturation. We hypothesise that the observed low investment of energy in reproduction by large female hake might be related to the lack of large males, due to a sex-selective fishery and the impact of El Niño. We suggest that fishing diminished hake reproductive capacity, modified the sex ratio in favour of females and increased population vulnerability to environmental stress, in particular to the El Niño. The impact of multidecadal variability and predators like the squid, Dosidicus gigas, remain unresolved until longer time series become available. 相似文献
9.
Barbara Niehoff 《Progress in Oceanography》2007,74(1):1-47
The present review addresses the reproductive strategies of marine calanoid copepods, as affected by their physiological preconditioning, and aims to enhance understanding of their adaptations to specific environmental conditions.Knowledge about oocyte development and internal gonad structure, especially in relation to feeding conditions, is essential for a complete understanding of the reproductive strategies of the copepods. Therefore, the foci of the review are to identify general patterns in oocyte and gonad development in calanoid copepod species from marine ecosystems worldwide and to elucidate the significance of gonad structures for reproductive strategies.Oogenesis is similar in all copepod species. During maturation, the morphology of the oocytes changes distinctly and, according to oocyte size and appearance of ooplasm and nucleus, five oocyte developmental stages are distinguished. In contrast, the gonad structure and its changes during the spawning cycle differ considerably among species, and these differences are related to specific reproductive traits.Four gonad morphology types can be distinguished: the Calanus-type, found in species from all over the world with distinctly different life history traits, is apparently most common in calanoid copepods. In this gonad type, most oocyte developmental stages are present simultaneously, and usually many oocytes mature synchronously, all of which are released in one clutch. The gonad structure allows frequent spawning and large clutches, hence, high egg production rates. This may be a preconditioning for exploiting seasonally high food supply. However, the Calanus-type was also found in species producing eggs at lower rates. In the diverticula of Pseudocalanus-type gonads, only two oocyte developmental stages are present and usually fewer oocytes mature synchronously. Accordingly, the egg production rate is generally lower as compared to the Calanus-type, and apparently only this gonad-type is structurally suitable for ovigerity. Species with Pseudocalanus-type gonads are present from polar seas to the tropics, some of them being key species. The Acartia-type was scarce, found in only one species, Acartia clausi. Here all oocyte developmental stages are present, including intermediate stages, but only a few oocytes mature synchronously and are released together. High spawning frequency compensates for the small clutches, and hence egg production rate may be as high as in Calanus-type gonads. In the Aetidius-type gonad, the total number of oocytes in the diverticula is low as is the number of oocytes maturing synchronously. Less is known about the reproductive biology of species with Aetidius-type gonads; however, their distribution and feeding patterns suggest that this type is common in species inhabiting environments of low food availability.The differences in gonad structures also lead to differences in the egg size:female size ratio, as the space available for each mature oocyte depends on the total number of oocytes. Independent from gonad-type, the eggs are relatively large in species in which the gonads contain only few oocytes, whereas small eggs are produced by species with gonads filled with many oocytes. Since all species carrying their eggs in external sacs until hatching (ovigerous species) have Pseudocalanus-type gonads, the scatter in their egg size:female size ratio is low. The broadcast spawning species are of all gonad-types, and consequently the scatter among them is high.A major factor affecting the timing and magnitude of spawning of calanoid copepods is the energy supply for gonad development. Therefore, part of the review elucidates the role of internal and external resources in fuelling egg production. In many species, freshly assimilated food is transferred into egg material within a short period of time, and clutch size and spawning frequency are the two parameters that allow adjustment of egg production to food availability and temperature. However, internal body reserves may also fuel oocyte development. The extent to which oogenesis depends on ambient feeding conditions varies considerably among species and even within species, apparently reflecting their adaptation to specific environmental conditions. All copepod species continue to release eggs for a short period after the onset of starvation, indicating that a short-term nutrient pool fuels final oocyte maturation. Some species, especially from polar and subpolar regions, are capable of reproducing on internal reserves, either solely or in addition to freshly ingested food, hence, decoupling the reproduction to some extent from the spring bloom. The reproductive strategy of Calanus finmarchicus, which responds with extreme flexibility to variations in food supply, is presented here as an example for the complexity of the reproductive processes in a calanoid copepod.In accordance with their physiological pre-conditioning, the calanoid copepod species exhibit distinctly different reproductive patterns. Polar and sub-polar environments are characterized by strong seasonality in light regime, and hence, phytoplankton concentration. The reproductive activity of many dominant (herbivorous) species peaks during the spring bloom. However, species that utilize internal reserves or food resources other than phytoplankton, reproduce before and after the bloom, or even year-round. In the North Atlantic, presented here as an example for a boreal marine ecosystem, maximum reproduction of the dominant copepod species Calanus finmarchicus occurs during the spring bloom. However, the timing of peak spawning varies between areas, as the onset of the bloom varies with hydrography and climate. The subtropical Gulf of Aqaba, in contrast to other subtropical systems, is characterized by seasonal phytoplankton succession driven by thermal winter convection. These changing environmental conditions, however, did not affect the reproduction of two of the dominant species, Clausocalanus farrani and C. furcatus. In contrast, other calanoid species exhibit reproductive cycles, either related to temperature (Ctenocalanus vanus) or to ontogenetic migration (Rhincalanus nasutus).The information gained from studies of morphology and reproductive traits contributes to standardization of methods in reproductive studies. Based on detailed knowledge of gonad morphology and its changes during maturation and due to food supply, classification schemata have been developed allowing the identification of females ready to spawn. In a next step, egg production may be estimated from preserved females by assessing clutch size through the number of maturing oocytes in the gonads. This approach, however, is as yet applicable only to the species best studied, Calanus finmarchicus.The present review shows that morphological studies on gonad maturation processes may provide significant contributions to fundamental ecological questions. Thus, they extend our knowledge of reproductive ecology from simply relating reproductive traits to abiotic and biotic factors toward a mechanistic understanding of how reproduction is regulated in calanoid copepods. 相似文献
10.
应用石蜡切片技术对海湾扇贝(Argopecten irradias)与紫扇贝(Argopecten purpuratus)的杂交品种——扇贝"渤海红"的性腺组织结构和生殖细胞发生规律进行了研究。扇贝"渤海红"大多为雌雄同体,但也存在雄性不育现象。性腺包括生殖滤泡、生殖小管和生殖输送管三个部分,滤泡是生殖细胞产生的主要场所。扇贝"渤海红"雄性生殖细胞发生经过了精原细胞、初级精母细胞、次级精母细胞、精细胞和精子五个阶段;雌性生殖细胞发生经过卵原细胞、小生长期卵母细胞、大生长期卵母细胞和成熟卵子四个阶段。 相似文献
11.
To obtain baseline information on the size distribution of individuals in the population and reproductive features of sea star Asterias amurensis, monthly surveys of the population were carried out from May to December 2010 and March to May 2015 in coastal waters off Yantai, China. Spawning period was predicted by gonad and pyloric caeca indices as well as anatomical and histological methods. In the A. amurensis population, both large individuals(143 mm) and small ones(42 mm) were present in all sampling months. The population size structure was driven by the appearance of big cohorts of individuals less than 55 mm from May to August. The appearance of small individuals in all months suggested a prolonged spawning period at other sites in this bay or sea stars growing slowly because of food shortage. An arm length is a good predictor to wet body weight for A.amurensis. The development of gonad was relative slow from May to September but rapidly reached a peak of20.95 in October 2010, and then dropped remarkably, indicating its spawning lasted from October to November.The same phenomenon was found from March to May 2015, suggesting another spawning during March to May,which was also verified by the results of histologic analysis on ovary. The gonad index(GI) and pyloric caeca index(PCI) tended to show a negative relationship. Due to the poor food availability, the reproductive characteristics of sea star were most likely affected by the shellfish mariculturein Yantai coastal waters. 相似文献
12.
Hyun-Sung Yang Do-Hyung Kang Heung-Sik Park Kwang-Sik Choi 《Ocean Science Journal》2017,52(4):519-526
Widely distributed from the northern coast of Vietnam to the northern Japan, the limpet Cellana grata (Gould, 1859) occurs commonly on the south and east coasts of Korea. Despite their wide distribution range, few studies have investigated the annual gametogenesis and reproductive effort of C. grata. In an attempt to understand the reproductive physiology of the limpet, we investigated the annual gametogenesis and reproductive effort of C. grata from Ulleungdo Island off the east coast of Korea. Histology revealed that the gonial mitosis commenced in January, as the female exhibited small oogonia (10–40 μm) in the follicle. From March to June, the oocyte size increased dramatically, and fully mature eggs (110–170 μm in diameter) appeared in early summer. First spawning males and females were observed in July, as the surface seawater temperature (SST) reached 22.1°C. The spawning male and females could be observed until the end of December. Gonad somatic index (GSI), a ratio of gonad mass to the total tissue weight, of the male ranged from 0.6 (April) to 17.9 (July), while the female GSI varied from 1.0 (February) to 18.3 (July). GSI of male and female declined rapidly from July to August, suggesting that the major purse of the spawning at the study site was between July and August. Our study suggested that the commercial catch of C. grata during July and August must be suspended at Ulleungdo Island, in order to protect the spawning limpets, which enhances C. grata recruitment and the population. 相似文献
13.
Aspects of the reproductive biology of the brown mussel Perna perna at the Iture rocky beach near Cape Coast, Ghana, were studied from September 2014 to August 2015. The current study was aimed at providing information useful for managing the mussel fishery in this locality and also that would form the basis for designing appropriate culture methods for the species. Microscopic examination of fresh smears of gonadal material, as well as histological preparations of the gonad, were used to study the sexuality and breeding pattern of the species. Monthly gonadal and condition indices were also determined. Perna perna exhibited gonochoristic sexuality with a sex ratio of approximately 1:1 throughout the study period. Sexes were identifiable at shell lengths of 15.0–19.9 mm. Five stages of gonadal development were identified in both sexes. Gametogenic activity was continuous throughout the year, with two major spawning activities, from April to June and from August to December. These periods coincided with the major and minor rainy seasons, respectively, as well as the major upwelling period in August. Condition indices suggest that the mussels were in better condition for harvesting in March and August prior to the major spawning events. 相似文献
14.
S. Buchanan 《新西兰海洋与淡水研究杂志》2013,47(5):859-870
The annual reproductive cycle of Perna canaliculus (Gmelin) was investigated for 1 year by collecting monthly gonad samples from an intertidal population. Gonads of 50 animals were dissected and photographically recorded on video before being fixed for histological sectioning. The histological gonad sections were examined both qualitatively, using a classification and scoring system (S) and quantitatively, using image analysis technology. The quantitative measures used were the proportion of: (1) sections comprising follicles (FC); (2) sections comprising gametes (GC); and (3) the proportion of follicles comprising gametes (G/F). Significant consecutive monthly changes in the qualitative and quantitative measures indicated major spawning events. Gametogenesis occurred during winter with a spawning in August‐September. Gonad condition remained low during the spring and early summer until a development period between January and March. A second major spawning event occurred between March and April. There was a high degree of synchrony in reproductive status observed between the sexes. When comparing the four measurement methods using the f statistic as an index of power the GC measure was found to be the most reliable. A gonad visual grading system was developed for rapid assessment of gonad reproductive status and tested. Visual grades of pre‐recorded gonad samples were compared to the histological measures. Increasing visual grade correlated strongly with increases in all of the histological measurements. The visual grading was a good predictor of the spawning activity of female P. canaliculus. 相似文献
15.
Reproductive cycle and gonadial changes in the New Zealand rock oyster Crassostrea glomerata 总被引：1，自引：1，他引：0
P. Dinamani 《新西兰海洋与淡水研究杂志》2013,47(1):39-65
The annual reproductive cycle and the cyclical changes in the gonad of the New Zealand rock oyster, Crassostrea glomerata (Gould, 1850), during the breeding period of 1970–71 and 1971–72 have been described. The gonad passes through an intermediate phase, after a post‐spawning period, when sex is indeterminate. Gametogenesis begins in July and August, but follicles ripen mostly during the spring months of October and November. Maximum development is seen in November, and nearly all oysters are in spawning condition in December and January. Major spawning takes place in January or February depending upon water temperature, and spawning continues until the end of March. Larvae may be found in the‐ plankton until late in the season, to the end of April or even May. Following spawning, gonadial regression sets in, with leucocyte infiltration and phagocytosis of residual gonial cells. A greater percentage of oysters more than 1 y old are females. The majority of oysters of age 1 y and below are males. 相似文献
16.
湛江北部湾海域养殖墨西哥湾扇贝重量性状增长规律的研究 总被引：2，自引：0，他引：2
采用模型拟合方法研究了湛江北部湾海域养殖墨西哥湾扇贝Argopecten irradians concentricus一个养殖周期的重量增长规律。结果表明,墨西哥湾扇贝各重量性状增长过程遵循Logistic生长模型。通过Levenberg-Mar-quardt迭代法求出模型中3个生长参数,建立了各性状生长方程,并得出各重量性状的生长极限值为体重28.29g、壳重17.27g、生殖腺重0.44g、软体部重11.21g、闭壳肌重5.35g;各重量性状的生长拐点分别为体重5.86个月、壳重6.11个月、生殖腺重5.01个月、软体部重5.55个月、闭壳肌重5.86个月,其中生殖腺重出现增长提早、壳重出现增长延缓现象;各重量性状的绝对增长速度为体重>壳重>软体部重>闭壳肌重>生殖腺重;重量性状相对于形态性状出现生长延缓现象。 相似文献
17.
《African Journal of Marine Science》2013,35(4):537-545
The reproductive cycle of the dwarf oyster Ostreola stentina (Payraudeau 1826) at Monastir in the south of the Gulf of Hammamet on the east coast of Tunisia was studied using condition indices and histological techniques. The species was shown to be a protandric hermaphrodite. Whereas males dominated the small shell length categories (12.45–34.99 mm), females (21.00–47.16 mm) and hermaphroditic individuals (30.00–57.95 mm) become more predominant with increasing size, suggesting that individuals may undergo protandric development. The overall male to female ratio was 1.0:1.7. Gametogenic development begins in February–March for females and in September for males, and spawning occurs during April and July for females and December and July for males. There was a clear relationship between the gonadal condition index and gametogenic stage for both sexes. Values increased from zero in their early stage of development and peaked during ripe and spawning stages, before decreasing in the spent stage. However, the meat condition index did not show any statistical differences between gametogenic stages. 相似文献
18.
The reproductive cycle of the abundant intertidal limpet Cellana ornata (Dillwyn 1817) was examined over 19 months, covering two breeding periods, on a rocky intertidal platform in southern New Zealand. A gonad index was calculated, and histological sections were used to count the numbers of mature and immature eggs present. Fecundity was estimated using counts of eggs before and after spawning. To determine any variation between sites, the gonad index of limpets at a second site dominated by boulders was examined over 6 months during the second breeding period. C. ornata had a single spawning period annually during summer, with greatest gonad sizes in January‐February. There were significant differences in peak gonad indices between two breeding seasons on the platform. Within the second breeding period, both the timing and magnitude of peak gonad development differed between sites, with lower reproductive output at the boulder site. Fecundity increased with increasing size, but individuals are probably capable of reproducing after their first year on the shore. The life history of this species is discussed in comparison to other limpets in New Zealand. 相似文献
19.
The community of the Japanese scallop Mizuhopecten yessoensis with its dominant endobiont polychaete Polydora brevipalpa, which bores into the scallop’s shell, was studied. It was established that the bulk of the scallop’s food ration consists of diatom algae and, to a lesser extent, flagellates and small invertebrates. The polychaete species considered mainly assimilates diatom algae and, to a significant degree, bacteria. Thus, the elements of the community enter competitive food relations. In the process of feeding, the scallop excretes detritus with its pseudofeces and this way increases the concentration of food available for polychaetes. In the course of its motion and filtration, the scallop enhances the water flow around the polychaete, which also favors the feeding of the latter. Meanwhile, negative relations between the degree of the population of the scallop’s shell by polychaetes and the volume of its internal cavity were recognized; this indicates a decrease in the potential for water filtering and, correspondingly, for food procuring by the host mollusk. With the increase in the polychaete-related bioerosion of the shell, the linear sizes and weight parameters of the scallop fall together with the rate of its growth. 相似文献