Genetic and morphological description of Eucalanus spinifer T. Scott, 1894 (Calanoida: Eucalanidae), a circumglobal sister species of the copepod E. hyalinus s.s. (Claus, 1866)

A distinct genetic form of the eucalanid calanoid copepod Eucalanus hyalinus s.l. was identified in subtropical and temperate waters of the Pacific, Atlantic, and Indian Oceans. Results from mitochondrial (16S rRNA, COI) and nuclear (ITS2) genetic markers suggest that the two E. hyalinus forms are reproductively isolated. Eucalanus spinifer T. Scott is taken out of synonymy with E. hyalinus and is applied to the smaller of the two genetic forms, increasing the number of species in the genus Eucalanus to a total of six. Adult females of the sister species E. hyalinus s.s. and E. spinifer can be distinguished morphologically by the shape of the anterior portion of the head in lateral and ventral views, asymmetry in the length of antennule segments 22 and 23, length ratios of 22/5 and 23/5 of the longer of the antennules, the length of the caudal rami, and total body size, as measured by total length or prosome length. We illustrate and describe both adult females and males of E. spinifer, and discuss aspects of sexual dimorphism. The sister species are sympatric throughout much of their circumglobal biogeographic distributions, but appear to have centers of abundance in slightly different water mass types.     

Submarine ridges do not prevent large-scale dispersal of abyssal fauna: A case study of Mesocletodes (Crustacea, Copepoda, Harpacticoida)

We examined the large-scale distribution of deep-sea harpacticoid copepods at the species level, in order to clarify the underlying processes of copepod dispersal. The study was based on samples collected from 12 regions and a total of 113 stations: 57 stations at depths between 1107 and 5655 m on abyssal plains in the South and North Atlantic, Southern Ocean, southern Indian Ocean, and the Pacific Ocean, and 56 stations above 900 m in the North Atlantic and eastern Mediterranean Sea.We chose the genus Mesocletodes Sars, 1909 as an ideal group to study the large-scale distribution of harpacticoid copepods in the deep oceans. Clear apomorphies and a comparatively large body size of about 1 mm allow rapid recognition of allied species in meiofauna samples. In addition, Mesocletodes represents more than 50% of the family Argestidae Por, 1986, one of the most abundant harpacticoid families in the deep sea.The geographical distributions of 793 adult females of Mesocletodes belonging to 61 species throughout the South and North Atlantic, Southern Ocean, southern Indian Ocean, Pacific Ocean, and eastern Mediterranean Sea indicated that most species are cosmopolitan. Neither the topography of the sea bottom nor long distances seem to prevent species from dispersing. Passive transport by bottom currents after resuspension is likely the propulsive factor for the dispersal of Harpacticoida, while plate tectonics and movement of individuals in the sediment may play relatively minor roles.     

东太平洋赤道海域茎柔鱼(Dosidicus gigas)的体型月间变化及环境效应

为了掌握茎柔鱼体型生长变化及其与栖息环境因子的效应关系, 2017年2—4月和6—8月,在东太平洋赤道海域逐月随机采集了3 628尾茎柔鱼样本,进行体质量、胴长的月间变化分析和胴长与海表温、叶绿素a浓度的效应关系研究。结果显示,雌性个体胴长分布范围为163—468mm,体质量分布范围为123—3034g;雄性个体胴长分布范围为171—475mm,体质量分布范围为145—2 681 g。不同月份之间,雌性、雄性个体的胴长和体质量均存在显著性差异,雌雄性个体胴长、体质量均以2月份的最大, 6—8月份的较小。然而,每个月份雌性、雄性个体的胴长分布均为单峰值区间分布。体质量-胴长幂函数关系显示,2—4月份雌雄性个体多倾向于匀速生长、体征较差,6—8月份个体则以负异速生长为主、体征较为良好。雌性、雄性个体胴长与采样海域海表温、采样纬度呈显著的正效应关系,采样海域叶绿素a浓度对雌性胴长产生正效应影响。研究表明,东太平洋赤道海域茎柔鱼体型的月间差异性显著,体型变化与采样海域海表温、采样纬度关系密切,并且雌性体型与海域叶绿素a浓度呈正效应关系。     

Morphological differences in Macoma balthica (Bivalvia,Tellinacea) from a Dutch and three southeastern United States estuaries

Field collections of the bivalve Macoma balthica in the Dutch Wadden Sea and three southeastern United States estuaries revealed morphological differences between populations of the two sides of the Atlantic Ocean. Individuals of the same age showed much larger shell lengths at the American stations. In addition, bivalves of the same body weight had higher siphon weights at the American stations than at the Dutch stations. This difference in siphon size was related to their burying depths. The American population, which invested more in heavier siphons, was able to burrow much deeper into the sediment (up to 30 cm). Deep burial may be an adaptation to avoid exposure to the high southern temperatures. Furthermore, it may serve as a refuge from blue crab predation. The results of our comparison between the southern American population and the European support the suggestion that populations of M. balthica living in these two regions should be considered separate and sibling species.     

An overview of Calanus helgolandicus ecology in European waters

We review current knowledge and understanding of the biology and ecology of the calanoid copepod Calanus helgolandicus in European waters, as well as provide a collaborative synthesis of data from 18 laboratories and 26 sampling stations in areas distributed from the northern North Sea to the Aegean and Levantine Seas. This network of zooplankton time-series stations has enabled us to collect and synthesise seasonal and multi-annual data on abundance, body size, fecundity, hatching success and vertical distribution of C. helgolandicus. An aim was to enable comparison with its congener Calanus finmarchicus, which has been studied intensively as a key component of European and north east Atlantic marine ecosystems. C. finmarchicus is known to over-winter at depth, whereas the life-cycle of C. helgolandicus is less well understood. Overwintering populations of C. helgolandicus have been observed off the Atlantic coast between 400 and 800 m, while in the Mediterranean there is evidence of significant deep-water populations at depths as great as 4200 m. The biogeographical distribution of C. helgolandicus in European coastal waters covers a wide range of habitats, from open ocean to coastal environments, and its contribution to mesozooplankton biomass ranges from 6% to 93%. Highest abundances were recorded in the Adriatic and off the west coast of Spain. C. helgolandicus is generally found in 9-20 °C water, with maximum abundances from 13-17 °C. In contrast, C. finmarchicus is found in cooler water between 0 and 15 °C, with peak abundances from 0 to 9 °C. As water has warmed in the North Atlantic over recent decades, the range of C. helgolandicus and its abundance on the fringes of its expanding range have increased. This review will facilitate development of population models of C. helgolandicus. This will not only help answer remaining questions but will improve our ability to forecast future changes, in response to a warming climate, in the abundance and distribution of this important species.     

Sexual traits plasticity of the potentially invasive limpet Bostrycapulus odites (Gastropoda: Calyptraeidae) within its natural distribution in South America

The slipper limpet Bostrycapulus odites has recently been reported as an introduced species on the Spanish Mediterranean coast. Another species in the family Calyptraeidae, Crepidula fornicata, is a problematic invasive species in the Northeast Atlantic, which makes the closely related Bostrycapulus introduction a matter of concern. Information on the biology of B. odites in its natural environment can facilitate predictions on where the species could find favourable conditions for settlement and expansion. Size and sex were recorded for individuals in four populations over 2600 km of the Southwestern Atlantic shoreline, in Argentina and Brazil, covering the whole native latitudinal range of this widely distributed species. Animals were collected by hand in the intertidal or by SCUBA in subtidal locations; specimens were examined to determine shell length, sex, and the presence and number of brooded egg capsules in females. Mean shell length for the whole population did not differ significantly among populations. However, this species experiences sequential hermaphroditism (protandrism), and the size at sexual maturity (minimum male size) increased significantly with latitude. The fecundity of females at all sites increased with size, and the number of brooded egg capsules as well as the average size of capsules was larger in bigger individual females; however, mean fecundity varied among sites independent of mean female body size. This limpet species modifies its reproductive traits with local conditions, and sexual characters develop earlier in more temperate localities.     

Life-history traits of the symbiotic scale-worm Branchipolynoe seepensis and its relationships with host mussels of the genus Bathymodiolus from hydrothermal vents

Associations between scale‐worms and giant mussels are common constituents of hydrothermal vent and cold seep ecosystems, but very little is known about their nature and ecology. Here, we analyze the ecological characteristics of the associations between Branchipolynoe seepensis, an obligate symbiotic polychaete, and their host mytilid mussels Bathymodiolus puteoserpentis and B. azoricus inhabiting hydrothermal vent fields on the Mid‐Atlantic Ridge. Infested mussels generally harbored a single symbiont (<4% had two to six worms). Infestation rate varied from 7.2% to 76.5%, increasing with mussel size, and was significantly lower for B. puteoserpentis. Symbiont density at Lucky Strike ranged between 1071 and 1191 individuals m⁻². Female symbiont size was always positively correlated with host size, while only males and juveniles from small mussels showed the same trend. This suggested a relatively long‐lasting host/symbiont association for females and short‐lasting association with successive reproductive migrations for adult males. The sex ratio of symbionts was always biased in favor of females. Males were smaller and more slender than females and had one mode in their size distributions, whereas females typically had three or more modes, suggestive of a longer life span in females. Between 59.1% and 72.2% of mussels had damaged soft tissues with substantially higher incidence of trauma in infested ones, suggesting that symbionts may cause trauma. The symbionts also induce tunnel‐like structures among the ctenidia, indicating fidelity to a particular location inside the host. Based on our data, together with the fact that infested mussels became relatively wider than non‐infested ones, this association is considered parasitic (likely kleptoparasitic). Our data, together with those from previous studies, allowed us to define the main life‐history traits of B. seepensis: (i) the relationship with their host is parasitic, (ii) the association begins at the smallest mytilid size classes, (iii) there is sexual dimorphism in body size, (iv) sex ratio deviates from 1:1 in favor of females, (v) fertilization occurs through temporal pairing and pseudocopulation, (vi) sperm are stored by females, (vii) eggs are large (likely lecithotrophic or with direct development), (viii) females have a longer life span than males, (ix) adult males may be semalparous, undertaking reproductive migrations followed by a short period of pairing and then death, and (x) females have a semi‐continuous iteroparous reproductive cycle.     

The deep waters from the Southern Ocean at the entry to the Argentine Basin

Hydrographic data from the World Ocean Circulation Experiment (WOCE) and South Atlantic Ventilation Experiment (SAVE) in the region of transition between the Scotia Sea and the Argentine Basin are examined to determine the composition of the deep water from the Southern Ocean that enters the Atlantic, and to describe the pathways of its constituents. The deep current that flows westward against the Falkland Escarpment is formed of several superposed velocity cores that convey waters of different origins: Lower Circumpolar Deep Water (LCDW), Southeast Pacific Deep Water (SPDW), and Weddell Sea Deep Water (WSDW).Different routes followed by the WSDW upstream of, and through, the Georgia Basin, lead to distinctions between the Lower-WSDW (σ₄>46.09) and the Upper-WSDW (46.04<σ₄ <46.09). The Lower-WSDW flows along the South Sandwich Trench, then cyclonically in the main trough of the Georgia Basin. Although a fraction escapes northward to the Argentine Basin, a comparison of the WOCE data with those from previous programmes shows that this component had disappeared from the southwestern Argentine Basin in 1993/1994. This corroborates previous results using SAVE and pre-SAVE data. A part of the Upper-WSDW, recognizable from different θ–S characteristics, flows through the Scotia Sea, then in the Georgia Basin along the southern front of the Antarctic Circumpolar Current. Northward leakage at this front is expected to feed the Argentine Basin through the northern Georgia Basin. The SPDW is originally found to the south of the Polar Front (PF) in Drake Passage. The northward veering of this front allows this water to cross the North Scotia Ridge at Shag Rocks Passage. It proceeds northward to the Argentine Basin around the Maurice Ewing Bank. The LCDW at the Falkland Escarpment is itself subdivided in two cores, of which only the denser one eventually underrides the North Atlantic Deep Water (NADW) in the Atlantic Ocean. This fraction is from the poleward side of the PF in Drake Passage. It also crosses the North Scotia Ridge at Shag Rocks Passage, then flows over the Falkland Plateau into the Atlantic. The lighter variety, from the northern side of the PF, is thought to cross the North Scotia Ridge at a passage around 55°W. It enters the Argentine Basin in the density range of the NADW.     

闽南近海尖头斜齿鲨的生殖生物学研究

尖头斜齿鲨(Scoliodon laticaudus)是暖水性小型鲨鱼,为有胎盘胎生种类.在闽南近海,其雄鱼的性成熟长度为382～448mm,雌鱼的性成熟长度为405～467mm,1994年5月至1995年4月的周年随机采样中,雌鱼在群体中所占比例为53.0%.雌鱼的妊娠开始于1～4月,同年的6～8月分娩,妊娠期为5～6个月.尖头斜齿鲨雌鱼每个子宫一次妊娠怀胚胎1～12尾,其中3～6尾者占67.8%.雌鱼一次妊娠产仔鱼2～24尾,平均9.1尾,其中6～13尾占70%;57%的母体左右子宫内胚胎数相同.胚胎数量随母体全长的增大而呈线性增加.雌性尖头斜齿鲨生殖周期约为2年,一生生殖2～3次,生殖能力较低.尖头斜齿鲨胚胎在分娩时全长138～142mm,与雌鱼性成熟长度的比为0.30～0.35,胚胎的雌雄比为1.17:1.同一子宫内及左右两子宫中的胚胎发育情况均基本相同.另外还讨论了鲨鱼资源的保护和管理问题.     

Reproductive traits of tropical deep-water pandalid shrimps (Heterocarpus ensifer) from the SW Gulf of Mexico

Heterocarpus ensifer is a tropical deep-water pandalid shrimp whose reproductive features are poorly known. We examined reproductive traits of a population of H. ensifer inhabiting the continental slope (311–715 m in depth) off the Yucatan Peninsula, Mexico (SW Gulf of Mexico). Size range of the total sample (n=816) was 10.4–38.9 mm carapace length. Females grow larger than males, but both sexes mature at 57% of their maximum theoretical size and at ～30% of their total lifespan. Among adult females, the proportion of ovigerous females was high in all seasons, indicating year-round reproduction. Most females carrying embryos in advanced stages of development had ovaries in advanced stages of maturation, indicating production of successive spawns. In the autumn, however, the proportion of ovigerous females and the condition index of these females were lower compared to other seasons. This pattern potentially reflects a reduction in food resources following the summer minimum in particulate organic carbon flux to the deep benthos, as reported in previous studies. Spawns consisting of large numbers (16024±5644, mean±SD) of small eggs (0.045±0.009 mm³) are consistent with extended planktotrophic larval development, an uncommon feature in deep-water carideans. Egg number increased as a power function of female size but with substantial variability, and egg size varied widely within and between females. There was no apparent trade-off between egg number and egg size and neither of these two variables was influenced by female condition. These results indicate iteroparity and a high and variable reproductive effort, reflecting a reproductive strategy developed to compensate for high larval mortality. The present study provides a baseline to compare reproductive traits between Atlantic populations of this tropical deep-water pandalid.     

Diet composition and feeding behaviour of juvenile Greenland halibut (Reinhardtius hippoglossoides) in the Svalbard area

The diet of trawl-captured juvenile Greenland halibut (Reinhardtius hippoglossoides Walbaum) from three locations on the western and northern coasts of Svalbard, Norway, in December 1995 and January 1996 is described. Stomach fullness was recorded for 1216 fish of 7 to 65 cm length, and stomach contents were analysed for 353 non-empty stomachs. The diet differed only slightly between the sampling areas and no differences were found between males and females. The overall percentage of empty stomachs (PES) was comparable to other nursery areas and lower than recordings from feeding and spawning areas. PES decreased and prey size increased as predator length increased. Fish and crustaceans dominated the diet, the most important prey species being Atlantic cod (Gadus morhua), polar cod (Boreogadus saida) and northern shrimp (Pandalus borealis). The relative importance of fish and crustaceans, respectively, was independent of predator length. However, a size-dependent variation in preferred prey was found, as smaller fish preyed upon small crustaceans and polar cod while larger individuals displayed a preference for northern shrimp, juvenile Atlantic cod, and other larger fish. Finally, there was a close resemblance between the length distribution of prey species from the trawl and from the stomachs.     

Distribution and size composition of the arctic lamprey Lethenteron camtschaticum in the North Pacific

Results of the long-term study of the spatial and vertical distribution of the parasitic anadromous Arctic lamprey Lethenteron camtschaticum (Tilesius, 1811) (Petromyzontidae) in the North Pacific and data on its size composition are given. This species is most frequent in the northwestern Sea of Japan and the western Bering Sea. The maximum concentrations are noted in waters of southern Primorye, southwestern Sakhalin, the northwestern part of the Sea of Okhotsk, and the northern part of the Bering Sea, which is probably explained by the increased number of its victims, Pacific salmon. Near the bottom, Pacific lampreys are extremely few and are primarily encountered at depths less that 400 m, and in the Pelagic zone, in the 100-m layer. The catches have contained Arctic lampreys having a total length of 15–79 cm. The lampreys of several size groups in the catches may indicate that L. camtschaticum spends not less than four years in the sea. No relationship has been found between the body length and the capture depth. Analyzed are the relationships between the body length and weight and the body length and the condition factor. The seasonal dynamics of these indices are considered.     

Temporal and spatial distribution of the two closely related Acartia species A. omorii and A. hudsonica (Copepoda,Calanoida) in a small inlet water of Japan

Temporal and spatial distributions of Acartia omorii and Acartia hudsonica were investigated in Maizuru Bay, middle Japan, from 1977 to 1978. In both years, adults of the two species appeared synchronously 17 days after the bottom temperature cell to 20°C in November; the numbers of both species sharply decreased when the bottom temperature rose to 20°C in late June and disappeared in early or mid-July. These facts indicate that a bottom temperature of 20°C is critical for the recruitment of the populations of these species. Acartia hudsonica was more limited to the inner position of the bay than A. omorii; spatial segregation may be explained not only by preference for different hydrographic conditions, but also by interspecific competition between the two species. In temperate waters, co-existing Acartia species belonging to the same subgenus appear to be segregated only in space while those of different subgenera usually exhibit a seasonal segregation. Pacific populations of A. hudsonica appear to be more restricted to inlet waters and estuaries than Atlantic populations, probably owing to the presence of the closely related sympatric species in the Pacific.     

西北冰洋陆坡区极北哲水蚤种群快速补充研究

在北冰洋的高纬度海区,陆坡—海盆之间的交换对极北哲水蚤（Calanus hyperboreus）的种群补充具有非常重要的意义。为了研究极北哲水蚤在西北冰洋种群补充的地理差异,我们利用2003年夏季所采集的样品,分析了该物种的丰度、种群结构和体长分布。从总丰度的地理分布来看,极北哲水蚤主要分布在楚科奇海与楚科奇深海平原之间的陆坡区（CS-slope）,而在水深较浅的楚科奇海并没有记录。在CS-slope区域,极北哲水蚤的总丰度在1 110.0—5 815.0个/m³之间,而其他海区的总丰度在40.0—950.0个/m³之间。从不同的发育期分布上来看,早期幼体（CI-CIV）在CS-slope区域占优势,而CV期幼体和成体在深水海盆区占优势。从体长的地理分布上来看,差异最为明显的是CⅢ期幼体,其在CS-slope区域的前体长在2.48—2.61 mm之间,而在其他海区的前体长在2.16—2.37 mm之间。与环境因子相关性的分析结果显示,早期幼体（CI-CIV）的丰度与叶绿素a的浓度呈正相关关系,而CV期幼体和成体却与叶绿素a的浓度呈负相关关系。我们的结果表明,极北哲水蚤可以通过加快第一个生长季节的发育速度而受益于初级生产力的增加,并且高生产力的CS-slope区域是陆坡-海盆之间种群补充的潜在来源。     

Population biology of Ischyrocerus commensalis,a crab‐associated amphipod,in the Southern Barents Sea: a multi‐annual summer study

Population biology of the amphipod Ischyrocerus commensalis Chevreux, 1900, a facultative commensal of the red king crab Paralithodes camtschaticus (Tilesius, 1815), is here described on samples collected during summers 2005–2009 in Dalnezelenetskaya Bay (Southern Barents Sea, Russia). The studied features included infestation indices, size composition, morphometric, and reproductive parameters of the summer generation. During the studied period, prevalence and mean number of I. commensalis per host were 34.4% and 54.4 ± 3.3 individuals, respectively. The majority of amphipods were found on the host mouth parts, limbs, and gills. The amphipod sex‐ratio was significantly biased towards females (F:M = 1.36:1). The size frequency distributions observed in July and August were similar but in July the proportion of the smallest amphipods (<2.1 mm body length) was two times higher than that in August. All the amphipods with body length >5.1 mm were males or females. Length–weight relationships in female and male amphipods differed significantly, suggesting that females were heavier than the same‐sized males. The females carrying eggs in their brood pouches were the most abundant groups (54.8% in July 2009 and 51.6% in August 2005–2008). The minimal body length of a female which had released juveniles was 7.0 mm in July and 6.2 mm in August. The size at 50% maturity of I. commensalis females was estimated to be 6.58 mm. The number of eggs laid is positively linearly correlated with the size of a female. The proportion of the females with eggs in the latest developmental stage in July was 10 times higher than in August. The differences of biological features in symbiotic amphipods between the July and August may be explained by more intensive reproduction effort in the earlier month.     

Habitat use patterns of the invasive red lionfish Pterois volitans: a comparison between mangrove and reef systems in San Salvador,Bahamas

The Indo‐Pacific red lionfish Pterois volitans is widespread both in its native and its non‐native habitats. The rapid invasion of this top predator has had a marked negative effect on fish populations in the Western Atlantic and the Caribbean. It is now well documented that lionfish are invading many tropical and sub‐tropical habitats. However, there are fewer data available on the change in lionfish abundance over time and the variation of body size and diet across habitats. A recent study in San Salvador, Bahamas, found body size differences between individuals from mangrove and reef systems. That study further suggested that ontogenetic investigation of habitat use patterns could help clarify whether lionfish are using the mangrove areas of San Salvador as nurseries. The aim of the present study is to determine temporal trends in lionfish relative abundance in mangrove and reef systems in San Salvador, and to further assess whether there is evidence suggesting an ontogenetic shift from mangroves to reef areas. Accordingly, we collected lionfish from mangrove and reef habitats and calculated catch per unit effort (a proxy for relative abundance), compared body size distributions across these two systems, and employed a combination of stable isotope, stomach content, and genetic analyses of prey, to evaluate differences in lionfish trophic interactions and habitat use patterns. Our results show that populations may have increased in San Salvador during the last 4 years, and that there is a strong similarity in body size between habitats, stark differences in prey items, and no apparent overlap in the use of habitat and/or food resources. These results suggest that there is not evidence an for ontogenetic shift from mangroves to reefs, and support other studies that propose lionfish are opportunistic forages with little movement across habitats.     

The taxonomic status of common dolphins Delphinus spp. in South African waters

Aside from gender differences, a principal components analysis of skull measurements of 72 adult common dolphins from South Africa failed to distinguish more than one form of Delphinus. Plots of rostral length against zygomatic width indicated most could be referred to the long-beaked form D. capensis, but three individuals lay outside this range, two of which were within the range for the short-beaked form D. delphis from the North Pacific. These were smaller individuals with significantly shorter beaks, longer flippers and wider flukes, and the colour patterns of two agreed completely or mostly with criteria for delphis. Their tooth counts were within (but close to the upper end of) the range for D. delphis, whereas other common dolphins in the region were within the range for D. capensis. Vertebral counts for all Delphinus from South Africa were similar and were well below those for D. capensis from the North Pacific. It is concluded that a smaller form of Delphinus, with characteristics mostly resembling those of D. delphis, occurs in South African waters, but (because of small sample size and the lack of complete agreement with published criteria for D. delphis from the North Pacific) its exact taxonomic relationship to D. capensis in this region is unclear.     

Sensitivity of tanaid Apseudes latreillei (Milne-Edwards) populations to sewage pollution

Apseudes latreillei (Milne-Edwards) is a common and abundant tanaid in soft-bottom communities from waters off East Atlantic and Mediterranean coasts. Its sensitivity to pollution is not clear despite being an abundant and widely distributed crustacean, since it has been reported as both a tolerant and sensitive species. This paper tests the sensitivity of A. latreillei to sewage discharges in fine-sand communities along the Castellon coast (W. Mediterranean). We analysed variation in tanaid populations between sites at varying distances from sewage outfalls with respect to population density, size distribution, sex ratio and their correlation with different abiotic factors of waste water and sediment. Results showed clearly that A. latreillei populations were affected by the presence of sewage outfalls, to such an extent that sewage disposal outlets produced a decrease in population density and changes in size spectra.     

Relationships between physiological stress and trace toxic substances in the bay mussel, Mytilus edulis, from San Francisco bay,California

Resident populations of Mytilus edulis from Tomales and San Francisco Bay, California, were measured for scope of growth, a physiological integration of the energy consumed by individual animals (feeding rate and assimilation efficiency) less the energy lost in metabolic processes (oxygen consumption and ammonia excretion). Scope for growth of mussels was significantly correlated (p≤ 0·05) with feeding rates. There was a significant decline in the scope for growth between the Golden Gate, at the bay's entrance and RedwoodCity in south San Francisco Bay. The scope for growth in resident M. edulis was significantly negatively correlated (p≤ 0·05) with increased environmental concentrations (from transplanted M. californianus body burden data) of the following trace elements and higher molecular weight chlorinated organic compounds: Cr, Cu, Hg (p ≤ 0·01) and Ag, Al, Zn, total chlordanes, and dieldrin. Scope for growth was significantly correlated (p ≤0·05) with body condition index (dry body weight1shell length).     

毛里塔尼亚外海乌贼成熟个体的体征研究

体征表征动物个体的健康状况,影响个体的体型及其生殖价值。乌贼(Sepia officinalis)营终生一次繁殖产卵,但性腺发育成熟个体的体征变化过程尚未可知。为此,本研究利用残差指标分析方法,对毛里塔尼亚外海分布的乌贼成熟个体的体征及其与体型、摄食强度关系进行了分析研究。结果显示,乌贼雌性成熟个体胴长范围为138～323mm,雄性成熟个体胴长范围为135～343mm;两者胴长呈单峰值区间分布,体质量与胴长呈显著的幂函数关系,幂函数拟合b值小于3。雌性、雄性成熟个体的体征存在一定的波动变化但不显著,在功能性成熟产卵期仍保持较好状态。同时,体征与胴长没有显著的函数关系,但是与胃饱满度密切相关,胃饱满度越高、体征越好;并且雌性、雄性成熟个体的空胃率比较低,在14%～34%之间。结果表明,毛里塔尼亚外海乌贼成熟个体保持个体生长,通过正常的摄食活动保持较好的体征。