Nest site characteristics and male reproductive success in the upland bully, Gobiomorphus breviceps (Eleotridae)

Abstract— The characteristics of male upland bullies ( Gobiomorphus breviceps ) and their nest sites were examined in two New Zealand streams as possible determinants of male reproductive success. There was no association between male size, nest site characteristics (depth, distance to shore, river velocity, nest rock size), and male reproductive success. Similarly, the male's parasite load had no detectable influence on reproductive success. Multiple regression analysis revealed that no combination of factors could explain the wide variation in male reproductive success. It may be that the unpredictable nature of the stream habitats of bullies has favored reduced choosiness in females, which could lead to an absence of correlations between male and nest characteristics and reproductive success.     

红螯螯虾雄性生殖系统的生化组成及精子代谢

通过对红螯螯虾（Cherax quadricarinatus）雄性生殖系统各组织的生化测定和乳酸脱氢酶（LDH）、琥珀酸脱氢酶（SDH）、延胡索酸还原酶（FR）的活性测定发现，红螯螯虾精荚（含精子）中的糖类和蛋白质含量丰富，分别为18．264和12．846mg／g（FW），总脂含量相对较低，仅为1．613mg／g（FW）；精子（含初级精荚壁）亦以糖类和蛋白质含量较高，分别达到5．227和8．475mg/g（FW），总脂含量因过低而未能测出，但精子的上述物质含量均显著低于精荚。酶活性测定发现，LDH酶活性以精巢、输精管和射精管较高，其中又以前输精管最高，为1426．258U／（g protein），可能与其功能相关；精子和精荚LDH活性极显著低于输精管，含量分别为87．375和36．215U／（g protein），两者间差异显著；FR活性在精荚和精子中较高，两者分别达到19．945和15．732U／（mg protein），显著高于生殖系统其他组织器官，但均未检测到SDH酶活性，故其SDH／FR的比值趋向于0。而生化物质的组织化学以及酶组化定位的结果进一步证实了上述结果。此外，LDH同工酶酶谱结果证实，精荚仅含有一条厌氧型LDHA编码亚基占优势的同工酶谱带。所有实验结果表明，红螯螯虾精子代谢的方式以厌氧型为主，其代谢底物主要为糖类，为厌氧型糖酵解，其代谢底物由次级精荚壁提供。     

Size-related factors causing individual variation in seasonal reproductive success of fluvial male Dolly Varden (Salvelinus malma)

Abstract– Reproductive activities of individually identified fluvial Dolly Varden ( Salvelinus malma ) were observed during a breeding season in a small stream. Males and females both established dominance hierarchies based on body size. Females spawned from late October to late November, with no apparent peak, and larger females spawned earlier than small ones. Males competed for access to females by adopting two types of mating tactics: pairing and sneaking. The tactic used depended on the male's position in the dominance hierarchy of the breeding group. Seasonal reproductive activity and mating success of males were positively correlated with body size, with only the largest male monopolizing most of the mating opportunities, and the small males were rarely successful in mating. Smaller males, however, lost as much weight as large males during the breeding season. Females preferred the largest male in the breeding group as a mate, while males courted females of any size. It is suggested that the polygynous mating pattern is a consequence of size-related differences in competitive ability among males, and the degree of monopolization is affected by both the temporal distribution and the spawning tactics of the females.     

Reproductive success of Atlantic salmon (Salmo salar) mature male parr in a small river,the Nivelle: influence of shelters

Grimardias D, Merchermek N, Manicki A, Garnier J, Gaudin P, Jarry M, Beall E. Reproductive success of Atlantic salmon (Salmo salar) mature male parr in a small river, the Nivelle: influence of shelters.
Ecology of Freshwater Fish 2010: 19: 510–519. © 2010 John Wiley & Sons A/S Abstract – The breeding activity of a small population of Atlantic salmon (Salmo salar L.) was monitored on the Nivelle River in southwest France to estimate the overall contribution of mature male parr and the numbers involved in egg fertilisation. In the twelve redds sampled, 563 eggs were collected for parental assignment and the physical habitat was characterised to investigate the possible relationship between parr reproductive success and habitat complexity. The overall contribution of mature male parr was particularly high (87%, one of the highest estimates ever reported). Concerning habitat complexity, granulometry and shelter diversity were correlated with the number of parr breeders contributing to egg fertilisation in each redd. A complex habitat increased multiple paternity, which could affect the effective size and genetic variability of small salmon populations.     

Red operculum spots,body size,maturation and evidence for a satellite male phenotype in non‐native European populations of pumpkinseed Lepomis gibbosus

Carotenoid‐based pigmentation is a striking feature of many taxa, yet the function, if any, of colour traits is often unclear. Pumpkinseed Lepomis gibbosus, a widely introduced freshwater sunfish that exhibits alternative male mating strategies, express a striking, red operculum spot. To investigate the potential function of this red spot as a signal in this species' mating system, we determined the presence and measured the size of red operculum spots in fish collected from 12 populations in five European countries in which pumpkinseed is an established non‐native species. We subsequently related the presence and size of the red spot to body size and mating strategy, based on an analysis of relative gonad size (gonado‐somatic index, GSI), using a mixed modelling approach. The study demonstrated that the presence of a red operculum spot in pumpkinseed is associated with sexual maturation, with GSI frequency distributions suggesting that cuckolders in some non‐native populations comprised both sneaker and satellite males, the latter not having previously been reported for this species. Further, the size of red spot correlated strongly with body size in parental and cuckolder males, although there was no difference in the presence or size of the red operculum spot between male mating strategies. The function of a red operculum spot in females is not clear but may be partly mediated by pleiotropic genetic mechanisms. Red operculum spots appear to function as signals of male maturation and body size in pumpkinseed, irrespective of mating strategy.     

中华绒螯蟹雄性生殖系统生化组成及精子代谢

通过对中华绒螯蟹肝胰腺及生殖系统各组织生化成分和乳酸脱氢酶(LDH)活性的测定发现:总碳水化合物的含量以副性腺及输精管内容物(含精荚和精浆)较高,为33.456mg·g-1湿重和21.537mg·g-1湿重,肝胰腺、精荚及精巢的含量较低;碳水化合物中的糖原和葡萄糖含量分别以输精管内容物和肝胰腺最高,分别为0.385mg·g-1湿重和5.866mg·g-1湿重,精巢和肝胰腺中的糖原含量太低而无法检测到,精荚葡萄糖含量最低;蛋白质含量以肝胰腺最高,其余各部分含量显著低于肝胰腺;脂类含量以精巢和肝胰腺最高,其中的甘油三酯仅存于肝胰腺和精巢,且肝胰腺含量显著高于精巢。乳酸脱氢酶活性以贮精囊最高,精荚仅为中等,这可能与精荚壁的通透性有关,而精浆和肝胰腺显著低于其它组织。结果表明,中华绒螯蟹能量代谢主要物质是脂类和蛋白质;精子代谢的能量物质为碳水化合物,并由精浆提供,而其代谢的方式以厌氧代谢为主。     

虾夷扇贝雄性生殖系统的组织学研究

１９９７年取材研究了大连长海县的虾夷扇贝的雄性生殖系统的组织结构。虾夷扇贝的精巢构造与栉孔扇贝,贻贝的相似,也是由外膜及其内的无数生殖小管构成。外膜含单层柱状上皮及较厚的肌层。生殖小管间充填着结缔组织及来自外膜的薄层肌肉,结缔组织中含有血管,神经及输精细管。生殖小管由位于基膜上的生殖上皮构成,生殖上皮不断向腔内增殖出精原细胞,初级精母细胞,精细胞及业郛。     

凡纳滨对虾选育群体与近交群体、引进群体生长和存活性能比较

为研究凡纳滨对虾选育群体与近交群体、引进群体的生长和存活性能差异,本实验利用家系标准化构建方法构建了选育群体、引进群体和近交群体家系,开展共同养殖环境下的生长和存活性能测试实验,分析了三个群体的体质量、存活率和近交衰退情况.结果表明,选育群体收获体质量与引进群体、全同胞近交一代群体体质量均存在显著差异(P＜0.05),第60天收获时,选育群体比引进群体的体质量提高7.11％,比近交群体的体质量提高20.01％;选育群体和引进群体内不同家系生长速度存在较大差异,选育群体中增重最快的家系为6012家系,绝对增重率为0.29 g/d,比所有家系绝对增重率均值高31.82％,比增重最慢的家系高61.11％,引进群体中绝对增重率和特定生长率均最高的家系为6008家系,分别为0.33 g/d和3.17％/d,比所有家系均值分别高65％和33.19％,比增重最慢的家系分别高230％和128.06％;存活率方面,选育群体与引进群体差异不显著(P＞0.05),但与近交群体存在显著性差异(P＜0.05),存活率提高12.74％.近交衰退结果显示,与选育群体及引进群体相比较,近交群体收获体质量生长性状的实际衰退百分比分别为16.68％和10.76％,近交系数每增加10％所引起的近交衰退系数分别为-6.60％和-4.30％,且选育群体与近交群体在收获体质量上差异显著(P＜0.05);存活率性状也出现了一定程度的近交衰退,实际衰退百分比分别为11.30％和10.54％.本研究结果可为凡纳滨对虾的后期选择育种工作提供数据参考.     

Reproductive success under the joint influences of temperature and salinity in noble scallop,Chlamys nobilis (Reeve)

In this study, the joint effects of two important environmental factors, temperature and salinity, on the per cent fertilization (FR) and per cent hatching (HR) of noble scallop, Chlamys nobilis, was evaluated using the central composite design and the response surface methodology. The results showed that the linear effects of temperature on FR and HR were significant (P < 0.01), and the linear effects of salinity were non‐significant (P > 0.05); the interactions between temperature and salinity were not significant (P > 0.05); the quadratic effects of temperature and salinity on the two responses were significant (P < 0.01); temperature was more important in influencing the reproductive success. The model equations of FR and HR towards temperature and salinity were established, with R² more than 98%, indicating that the models had excellent ability for goodness of fit and projection. Through simultaneously optimizing the two models derived, we found out that the optimum factor combination was 25.7°C/29 ppt and the greatest reproductive success was 89.93% for FR and 72.42% for HR. The desirability value of 97.30% showed the reliability of these optima. Our results provide some valuable guidelines for refining the reproductive efficiency of C. nobilis.     

Ocean's eleven: a critical evaluation of the role of population,evolutionary and molecular genetics in the management of wild fisheries

Significant changes have occurred in the well‐established partnership between fisheries managers and geneticists over the last 50 years. It is therefore timely to review and recalibrate the ways in which genetic technologies can assist the fishing industry to maintain productive and sustainable harvests. Our objective is to contribute to the mutual understanding of all stakeholders in the genetics–management partnership. Genetic technologies that are relevant to fisheries management are grouped into eleven themes, which are described in plain language for a non‐specialist audience. The role that the genetic information plays in fisheries management is explained, along with an assessment of the challenges and barriers that may be preventing the uptake of the information into the fisheries management process. The compelling conclusion is that genetics offers a diverse collection of versatile and useful tools for informing fisheries managers about issues that have a biological basis. Presently, mainstream use of genetic tools focuses on a narrow set of fisheries management issues, but the diversity of genetic tools and the novel issues they can address indicates that uptake will grow, particularly as communication between geneticists and end‐users improves.     

Ocean eddies,predator pits and bluefin tuna: implications of an inferred ‘low risk–limited payoff’ reproductive scheme of a (former) archetypical top predator

The conventional view of the reproductive ecology of bluefin tunas (Thunnus thynnus, Thunnus orientalis, Thunnus maccoyii) leads to a conceptual paradox. Simple arithmetic yields an expectation for wide variation in annual reproductive success. However, the historical record does not support this prediction. A conclusion would seem to be that a much stronger than usual density dependence must be acting. It is here argued that this strong density dependence may likely occur within small strongly convergent segments of energetically forced ocean eddy structures. Success of the implied ecological scenario requires spawning schools of sufficient size to generate sufficiently copious reproductive product to circumvent resident predator pits, while exerting sufficient predatory loss on resident predators to facilitate this circumvention. This in turn implies existence of a dangerous ‘precipice’ in the form of self‐enhancing feedback loop, lurking unperceived beyond the range of historical experience, and a need for a particular degree of precaution in managing the exploitation of this iconic species.     

Prespawning migratory behaviour and spawning success of sea-ranched Atlantic salmon, Salmo salar L., in the River Gudenaa, Denmark

The migratory behaviour of sea-ranched Atlantic salmon, Salmo salar L., was analysed by radio-telemetry in the River Gudenaa, Denmark. The main objectives were to: (1) estimate mortality of returning adults through the fjord; (2) observe rate of progression and migratory pattern in the fjord and river; and (3) record whether spawning occurs in the river. Forty-two returning salmon (19 males and 23 females of total body length from 60–97 cm) reared and released as smolts, were caught and equipped with external radio transmitters in the outer estuary of the River Gudenaa in 1994 and 1995. Of the tagged salmon, 18 (43%) were caught in the estuary, four (10%) were not recorded after release and 20 (47%) entered the river. The mean rate of progression through the fjord was 7.6 km d−1 (range 1.4–18.2) in 1994 and 5.4 km  d−1 (range 1.6–17.1) in 1995. Eleven salmon were alive at the onset of the spawning period. Eight were retrieved dead from the river during or after the spawning period; four with empty gonads assumed to be successful spawners, and four with intact gonads. In 1994, unsuccessful spawners (found dead with intact gonads) entered the river earlier and had a longer total migration distance in the river compared to successful spawners. This suggests that spawning success of sea-ranched salmon is associated with time of river entry and river migration length.     

Influence of pejerrey Odontesthes bonariensis (Valenciennes, 1835) broodstock age on gamete quality,reproductive performance and plasma sex steroid levels during the spawning season

This study evaluated the effect of pejerrey Odontesthes bonariensis (Valenciennes, 1835) broodstock age on gamete and spawning quality and its relationship with sex steroid plasma levels. Sperm was analysed using a computer‐assisted sperm analysis (CASA) developed for pejerrey. Semen samples were taken from all fish from mid age groups (5‐ and 7‐year fish), but it was not possible to obtain stripped semen samples from all fish of younger (3‐year) or older (10‐year) groups. The highest relative sperm weight and sperm concentration were recorded in 5‐ and 7‐year groups respectively, while viability was not different between age groups. It was not possible to identify an effect of age on sperm quality by CASA. Non‐viable spawned eggs were obtained in the 3‐year group and, the relative fecundity and the relative number of fertilized eggs decreased with age in other groups. Fertilization and hatching rates showed the highest values in the 10‐year group. However, the estimated number of hatched larvae was similar in 5‐, 7‐ and 10‐year fish. A clear effect of age on 11 ketotestosterone (11‐KT) and estradiol (E₂) levels was identified, with the highest values in the 5‐ and 7‐year groups. These results might be related to the onset of puberty in the 3‐year group and ageing in the 10‐year group. Considering that the estimated number of larvae obtained was similar among age groups, the results of this study suggest that broodstock maintenance cost could be reduced by using mid‐age fish rather than older fish in pejerrey hatcheries.     

Life-history of the flagfin shiner, Pteronotropis signipinnis, from a blackwater stream in southeastern Mississippi

Abstract – Flagfin shiners, Pteronotropis signipinnis , were collected from Sweetwater Creek, a second-order blackwater stream in southeastern Mississippi, during each month of 1996. Analysis of length frequency histograms indicated a life span of 1 to 2 years. Sex ratio was not different from a 1:1 ratio. Adult males were larger and more heavily pigmented near the abdomen than females. Females were reproductive from April to mid-August. All females attained sexual maturity by 27 mm SL and produced multiple clutches of ova. Clutch size varied from 12 to 101 ova and was correlated with SL. Mean mature oocyte diameter was 0.88 mm (range 0.76–0.96). Despite the relationship between clutch size and body size, P. signipinnis may be selected to invest in early reproduction rather than growth. This idea is supported by the small size at maturity in this species and is consistent with an opportunistic life-history strategy. ^Note     

Long-term variation in brown trout, Salmo trutta L., stocking success in a large lake: interplay between availability of suitable prey and size at release

Abstract –  Factors affecting long-term variation in brown trout, Salmo trutta L., stocking success were examined in a large lake, Lake Oulujärvi, in central Finland. Brown trout were stocked in spring (late May to early June) in 1974–1991 and in summer (late June to early July) in 1992–2001. The biomass of the vendace, Coregonus albula (L.), population (prey) at release time had the largest positive effect on stocking success within both periods: biomass of adult vendace in spring and both 0+ and adult vendace in summer. Increasing the size of stocked fish had a positive effect if the vendace available at release were only adults. The increasing trend of predator-catch-per-unit-effort (CPUE) [combined CPUE of northern pike Esox lucius L., burbot Lota lota (L.), and pike-perch Stizostedion lucioperca (L.)] through the study period and its negative effect on trout stocking success suggested an increasing effect of predation within the entire time series.     

Feeding success and survivorship of Arctic cod larvae,Boreogadus saida,in the Northeast Water polynya (Greenland Sea)*

We tested the hypothesis that enhanced feeding success and survivorship of Arctic cod larvae in the Northeast Water polynya (Greenland Sea) are associated with high densities of their zooplankton prey in areas of low sea ice concentration. From late May to early August 1993, first-feeding yolk-sac larvae (6.5–8.5 mm long) were collected primarily along the coast and over shallow banks in the polynya, whereas post yolk-sac larvae (8.5–14 mm) were more uniformly dispersed over the sampling area. Arctic cod larvae < 14 mm fed almost exclusively on copepod nauplii (74% of total prey number) and copepod eggs (16%). Feeding success was defined as the residuals of the regression of the number of prey ingested against larval length. Nauplii density varied from 9600 to 731300 nauplii m^-2(equivalent to 0.16 to 12.2 nauplii 1^-1) but, contrary to our hypothesis, seldom limited the feeding success of Arctic cod larvae. Water temperature was the best predictor of feeding success in larvae of all sizes. First-feeding success and survivorship were low for larvae hatched before mid-July, and improved thereafter as surface temperatures increased in the open waters of the polynya. There was no relationship between feeding success and irradiance or wind. Assuming a fixed spawning season, it is concluded that a larger fraction of the newly hatched larvae would experience adequate temperatures in years when the polynya opens early. Based on this conclusion, we propose that the timing of the opening of polynyas is a critical determinant of year- class strength in Arctic cod, a key species in the Arctic food web.     

长江水系野生和养殖中华绒螯蟹生殖性能、胚胎色泽和生化组成的比较

生殖性能是评价水生动物亲本质量的重要指标,本研究测定和比较了野生和养殖中华绒螯蟹亲本的生殖性能、胚胎质量、胚胎色泽、常规生化和脂肪酸组成。结果显示:①野生中华绒螯蟹亲本的生殖力、生殖指数和抱卵量略高于养殖亲本的,但2组间无显著性差异,野生和养殖中华绒螯蟹亲本的胚胎单卵湿重、单卵干重和卵径无显著性差异;②养殖组冻干胚胎的红度(a~*)、黄度(b~*)值和总类胡萝卜素含量显著高于野生组亲本,然而2组胚胎的亮度(L~*)和色差值(dE~*)无显著性差异;③2组亲本所产胚胎的水分、粗蛋白和粗脂肪含量均无显著性差异,但其脂肪酸组成差异显著,野生组胚胎的C18:1n9、C18:1n7、C20:4n6、C22:5n3和C22:6n3显著高于养殖组,但其C18:2n6和C18:3n3含量显著低于养殖组。研究表明,池塘养殖和野生亲本的生殖性能和胚胎中常规生化组成无显著差异,但2组胚胎的色泽、总类胡萝卜素含量和部分脂肪酸组成存在显著差异,该研究为中华绒螯蟹亲本选择、生殖性能评价和人工育苗提供了重要基础资料。     

Changes in Sperm Production,Sperm Motility,and Composition of Seminal Fluid in Caspian Brown Trout,Salmo trutta caspius,Over the Course of a Spawning Season

This study was carried out to evaluate milt quality in male Caspian brown trout (Salmo trutta caspius) over the course of the winter spawning season. Milt samples were collected biweekly during December and January. Chemical composition of seminal fluid, sperm production (milt volume, sperm density, spermatocrit,) and sperm motility characteristics (percentage and duration of motility) were measured. Milt volume, sperm density, osmolality, seminal minerals (Ca²⁺, Mg²⁺, K⁺, Na⁺, Cl^?), and total protein gradually decreased over the spawning season. Glucose and triglyceride content of milt did not show significant changes over the spawning season. Milt pH and the percentage and duration of motility were comparatively stable, declining only at the end of the season. Significant positive correlations were found between sperm density and seminal minerals, total protein and spermatocrit; percentage of motile spermatozoa and seminal minerals, total protein; and duration of motility and K⁺, Cl^?, total protein, and pH. Results show that season has a significant influence on milt quality in male Caspian brown trout, with the best milt being available at the beginning of spawning season.     

Distribution of the introduced cyprinid herpesvirus 3 in a wild population of common carp, Cyprinus carpio L.

Cyprinid herpesvirus 3 (CyHV-3), which causes a lethal disease in common carp, Cyprinus carpio L., and koi, C. carpio koi , first occurred in Lake Biwa, Japan in 2004. To elucidate distribution of CyHV-3 in a wild common carp population, we conducted a PCR survey of CyHV-3 among such fish in Lake Biwa in 2006. Only 6% (1/18) of the common carp smaller than 300 mm were positive with PCR, whereas 31% (18/58) of fish larger than 300 mm were positive. To evaluate their past exposure to CyHV-3 infection based on the presence of antibodies, we also measured the levels of serum anti-CyHV-3 antibodies in the carp, using an enzyme-linked immunosorbent assay. None (0/26) of the fish smaller than 300 mm was positive for the antibodies, whereas 54% (33/61) of fish larger than 300 mm were positive. Of the antibody-positive individuals, 44% (14/32) were also positive by PCR strongly suggesting that wild common carp that survived infection become CyHV-3 carriers. Five individuals were positive by PCR but negative for antibodies indicating that their infection with CyHV-3 had occurred recently. These results suggest that transmission of CyHV-3 from carriers to naïve common carp is still occurring in Lake Biwa.