Spawning behaviour of amemasu charr,Salvelinus leucomaenis leucomaenis,with a discussion of the macroevolutionary patterns of postspawning behaviour in the Salmoninae

Abstract – Video cameras inside underwater housings were used to record the spawning behaviour of a subspecies of the white‐spotted charr, the amemasu charr (Salvelinus leucomaenis leucomaenis) in the Tokimae and Onbetsu Rivers, Hokkaido, Japan. Unlike other Salvelinus species, in which females use lateral swings of their bodies to ventilate and distribute eggs over gravel crevices (undulating) immediately after spawning, female amemasu charr covered their eggs with beats of their tails (cover digging). Cover digging right after spawning has previously been documented in Salmo, Oncorhynchus and Parahucho. Phylogenetic analysis of postspawning behaviours in the Salmoninae indicated that (i) resting then covering the eggs is plesiomorphic for the group, (ii) undulating replaced resting in the ancestor of Salvelinus, (iii) cover digging was advanced in the behavioural sequence to occur immediately after egg deposition in the ancestor of Parahucho + Salmo + Oncorhynchus and in the amemasu.     

鱼类产卵孵化方式及其适应意义

综述了卵生鱼类的浮性卵、粘性卵、沉性卵及特殊类型的产卵孵化方式及其适应意义,也描述了卵胎生和胎生鱼类的胚胎发育及产仔特征。     

Spawning of the broad-finned Galaxias, Galaxias brevipinnis Günther (Pisces: Galaxiidae) in coastal streams of southeastern Australia

Abstract— The broad-finned galaxias, Galaxias brevipinnis , spawned during high flows in mid autumn. Spawning took place over inundated riparian areas where eggs were laid amongst substrate, mainly in the interstices of cobbles and pebbles. Between subsequent high flows, eggs were out of water for days or weeks, lying up to 7 m from the water's edge. When exposed, eggs and streamside substrate remained damp, shaded by surrounding forest. Hatching would only occur when eggs were inundated by a subsequent flood. In the field, most eggs had hatched within 30 days of the spawning period, but some remained unhatched for up to 60 days. In the laboratory, eggs remained unhatched for up to 57 days under moist conditions but out of water, and up to 120 days when kept in water. However those kept under drier conditions died. It would appear that riparian cover may be important in providing shaded and moist conditions for the survival of eggs in the wild. Evidence of some adult mortality following spawning was noted. Newly hatched larvae were carried to sea during high flows. Predation on eggs by both adult G. brevipinnis and introduced brown trout Salmo trutta Linnaeus was found to occur.     

Characteristics and rehabilitation of the spawning habitats of the sea trout, Salmo trutta, in Gotland (Sweden)

Characteristics of the natural spawning habitat of sea trout, Salmo trutta L., were studied in Själsöån, a small stream of Gotland, Sweden, from 1992 to 1999. Each year, trout spawned on 17 ± 7 different areas (156 places ha^?1). Most of the spawning grounds were used every year. Overcutting was evident for at least 60% of the spawning grounds. Fish spawned on a gravel of 19 ± 7 mm in diameter. From 1978 to 1992, 242 artificial spawning grounds were constructed by the Gotland Sport Fishermen Association in four Gotland streams. A sediment trap was dug upstream to the spawning grounds. The artificial spawning ground comprised of a downstream V‐shape stream deflector of large stones with a log weir at the narrowest point of the deflector. Upstream of the dam, 15–60 mm diameter gravel was deposited to constitute the spawning ground substratum. To keep the installation efficient, maintenance is needed every year before the spawning season.     

葛洲坝产卵场中华鲟繁殖群体数量与繁殖规模估算及其变动趋势分析

采用声学探测的方法,进行中华鲟(Acipenser sinensis)繁殖群体数量的估算.2005～2007年,第1次产卵前的资源量分别为235尾、217尾和203尾;第1次产卵后的资源量分别为157尾、157尾和102尾.采用食卵鱼解剖统计和股分析的方法对中华鲟的自然繁殖规模进行估算.其结果为,2005～2007年间中华鲟的产卵量分别为356万粒、119.6万粒和238.6万粒.结合历史相关研究数据,对近10年的中华鲟繁殖群体数量和繁殖规模的变动趋势进行分析,结果显示,在20世纪90年代中期,第1次产卵前的中华鲟繁殖群体数量下降趋势明显,但2002年以来其数量趋于基本稳定,年际间的差异没有统计学意义(P>0.05).自2002年以来,第1次产卵后停留产卵场的中华鲟数量有增加的趋势,而中华鲟的繁殖规模近10年来呈现极其显著性的下降趋势(P<0.01).     

Skipped spawning in female iteroparous fishes

It is often assumed that iteroparous fishes spawn annually once reaching sexual maturity, but this is not always the case. This paper reviews available information on skipped spawning in female teleost fishes. All instances of non‐annual spawning are described as one of three types (retaining, reabsorbing, resting), depending on where in the normal spawning cycle development has been interrupted. Retaining ripe eggs is caused by conditions experienced during the spawning season (fish density, mate availability, pollution), whereas failure to start vitellogenesis (resting) or the breakdown of all oocytes that enter into vitellogenesis (reabsorbing) is caused by factors experienced prior to the spawning season (primarily temperature and poor nutrition). It is speculated that the relative shortage of data on non‐annual spawning may be because of difficulties in identifying non‐reproductive individuals. In an attempt to rectify this situation, the criteria needed to identify females undergoing the three forms of spawning omission are presented in terms of external appearance of gonads, gonad indices, and histological analysis. The energy saved by not spawning in a poor year may lead to increased survival and the probability of spawning in subsequent years. As the cumulative number of progeny gained by surviving to spawn in multiple subsequent years outweighs the number of progeny lost by not spawning in a given single year, occasional omission of spawning may constitute an adaptive trait in long‐lived iteroparous fishes.     

眼斑拟石首鱼苗种生产技术

介绍了眼斑拟石首鱼的生长与繁殖特性，亲鱼选择和采卵方法，以及受精与孵化技术，并提出了仔鱼前期、仔鱼后期、稚鱼期、幼鱼期的鱼苗培育措施。     

金乌贼新型产卵附着基的实验研究

2015年6—7月和2016年6—7月在青岛金沙滩水产有限公司室内产卵池中开展了不同材料、不同颜色、不同水深金乌贼(Sepia esculenta)产卵附着基附卵效果对比实验,以及柽柳附卵器对附卵效果的影响实验。实验用产卵附着基为0.33 m×0.33 m×0.33 m的十字形可折叠钢丝框架,上覆黑白2种聚乙烯网衣材料;每个产卵池中金乌贼亲体数量约35只,雌雄比约为1∶1,胴长(139.2±1.1)mm,体重(435.9±8.5)g。同时选用等比例放大的1.0 m×1.0 m×1.0 m钢筋框架与不同颜色网衣制作的十字形可折叠附着基,于2015年6—7月在青岛斋堂岛附近海域(35?36?6?N,119?54?8?E)和杨家洼湾前附近海域(35?36'6?N,119?50'50?E),以及2016年6—7月在青岛薛家岛近海(35?57?24?N,120?16?22?E)和杨家洼湾前附近海域(35?35?45?N,119?50?38?E)开展了海区附卵验证实验。结果表明:室内同一水体环境中柽柳附卵效果最佳,其次是十字形附着基,海参框附卵效果最差;白色十字形附着基的附卵效果显著优于黑色(P0.05);柽柳附卵器对附卵效果有积极影响,加装柽柳附卵器的十字形附着基附卵效果明显提高;产卵池底层摆放的十字形附着基的附卵效果显著优于表层悬挂的十字形附着基(P0.01)。海区附卵验证结果表明:2015年和2016年海区投放的十字形附着基附卵效果良好,最高附卵率分别为82.14%和56.72%;海区投放的黑色和白色十字形附着基的附卵效果差异不显著(P0.05);海底悬挂的十字形附着基的附卵效果显著优于近底层悬挂的十字形附着基(P0.05)。综合分析认为,在金乌贼产卵繁殖季节,选择其重要产卵场和主要增殖放流海区水深15~20 m的缓流区,底层设置十字形可折叠产卵附着基,可有效进行资源增殖与产卵场修复。     

Demographics of the spawning aggregations of four catostomid species in the Savannah River, South Carolina and Georgia, USA

Abstract –  Differences in the life history strategies employed by otherwise ecologically similar species of a fish assemblage may be an important factor in the coexistence of these species and is an essential consideration in the conservation and management of these assemblages. We collected scales to determine age and growth of four species of the catostomid assemblage (northern hogsucker Hypentelium nigricans , spotted sucker Minytrema melanops , notchlip redhorse Moxostoma collapsum and robust redhorse Moxostoma robustum ) of the Savannah River, Georgia–South Carolina in spring 2004 and 2005. Robust redhorse was the largest species; reaching sexual maturity at an older age and growing faster as a juvenile than the other species. Spotted sucker did not achieve the same size as robust redhorse, but reached sexual maturity at younger ages. Notchlip redhorse was intermediate between the abovementioned two species in age at maturity and size. Northern hogsucker was the smallest species of the assemblage and reached the sexual maturity at the age of three. Both robust redhorse and spotted sucker were sexually dimorphic in size-at-age. The range of life history strategies employed by Savannah River catostomids encompasses the range of life history strategies exhibited within the family as a whole.     

Recruitment patterns of six species of cyprinid fishes in the lower River Trent, England

Abstract – Fisheries data were collected for six species of 0-group cyprinid fishes from eight sites in the lower reaches of the River Trent, England, between May and October 1999 inclusive, using a micromesh seine net. Recruitment and growth patterns were observed via monthly length–frequency histograms and estimations of mean length. In the cases of roach and dace, growth was approximately linear through the summer, before declining in September and October. In the cases of chub and gudgeon, and to a lesser extent bream and bleak, however, there were suggestions of multiple recruitment events. It is argued that some of the fish species examined in the present study adopt fractional or protracted spawning strategies in the lower River Trent.     

鲶鱼的人工繁殖

鲶鱼Parasilurus asotus属鲶形目、鲶科,鲶属,为我国最常见(王以康,1958)鱼类。该鱼分布广,适应性强,是肉食性鱼类,具有较高的经济价值,肉质细嫩,营养丰富。在北方常作为产妇的营养补品和餐桌上的美味佳肴。目前市场上的鲶鱼主要来源于天然捕捞,供应不稳定,然而价格也高于鲤鱼等养殖鱼类。过去该鱼被视为养鱼敌害,但现已逐渐改变了这种观念,成为池塘的混养对象。在黑龙江     

Variations in spawning ground area and egg density of the Japanese sardine in Pacific coastal and oceanic waters

The spawning ground of the Japanese sardine, Sardinops melanostictus (Schlegel), was distributed over the oceanic waters as well as the coastal waters along the Pacific coasts of western and eastern Japan during 1978–1992. The area of the spawning ground in the coastal waters on the continental shelf has ranged from 95 000 km² in 1992 to 143 000 km² in 1988, constituting 44–77% of the total area of the spawning ground. The area of the coastal spawning ground was relatively constant in spite of the large fluctuations in egg abundance, i.e. size of the spawning population, from 88 trillion (1987) to 668 trillion (1989) in the waters. Spawning adults seemed to extend over the coastal waters irrespective of the size of the spawning population. In contrast to the coastal waters, the spawning area in the oceanic waters offshore of the continental shelf increased from 31 000 km² in 1978 to 183 000 km² in 1988 and then shrank to 83 000 km² in 1992, as a function of the spawning population size. The egg distribution density in the coastal waters stayed less than 6000 m⁻² mo⁻¹, but it reached as high as 27 400 m⁻² mo⁻¹ in the expanded spawning ground in the oceanic waters. The oceanic waters seemed to function as a reserve spawning ground for the sardine in years of extremely high spawning population.     

Captive breeding of climbing perch Anabas testudineus (Bloch, 1792) with Wova-FH for conservation and aquaculture

Induced breeding of climbing perch, Anabas testudineus was conducted by synthetic hormone Wova‐FH in the intensity level of 0.1, 0.2 and 0.3 mL kg^?1 of body weight respectively. The brooders were injected one time and left to spawn in the spawning hapa in the sex ratio between male and female as 2:1. It was found that at all the intensity level hormone Wova‐FH could enhance the fishes to breed and lay eggs whereas no breeding was observed in control set. The spawning time, quantity of the brooder spawn, fertilization rate, hatching rate and survival rate were quantified in each set of experiment. The egg output/female was significantly higher in 0.3 mL in comparison with 0.1 and 0.2 mL kg^?1 of body weight. The statistical analysis showed significant (P≤0.05) effect between hormone dose on fertilization rate, egg output and hatching rate. The present experiment suggests that Wova‐FH at the dose of 0.3 mL kg^?1 body weight of fish is more effective which might be considered for raising captive population.     

Spawning of North Sea fishes linked to hydrographic features

Spawning of fishes takes place across a wide area of the North Sea. However, more intense spawning is seen in restricted areas, indicating that such areas present favorable conditions. To update information on fish spawning in the North Sea and analyze potential linkages to hydrographic characteristics, an internationally coordinated survey was conducted in the winter/spring of 2004. Oblique hauls for fish eggs and larvae and vertical profiles of temperature and salinity were carried out at 393 stations across the entire North Sea. The hydrography was strongly influenced by the interfacing of water masses of different salinity, and frontal zones were seen along all coastal areas and off the Dogger and Fisher Banks. Total abundances of eggs and larvae, including fish species such as cod, haddock, plaice, long rough dab and sandeel, peaked in the vicinity of the frontal areas. Hence our findings indicate that the main spawning locations of fish are linked to recurrent hydrographic features such as salinity fronts. Such a linkage may provide survival advantages, as the fronts present favorable feeding conditions, and the related physical processes may confine egg and larval dispersal and transport them towards suitable nursery habitats.     

Spawning grounds and maturation status in adult flathead flounder Hippoglossoides dubius off Niigata Prefecture, Sea of Japan

Investigations were conducted on the flathead flouder Hippoglossoides dubius to analyze the environmental conditions around the spawning grounds and the maturational status of spawners in the Sea of Japan off Niigata. In both sexes, larger fish matured earlier than smaller individuals, and participated in breeding from the early part of the spawning season. Males were always the predominant sex found within the spawning ground, likely because males spent longer periods in the spawning grounds than females. This finding further suggests that males matured earlier and maintained sexual activity for longer periods than females within the spawning grounds. Submarine topography and water temperature were concluded to be important factors affecting the formation of the spawning grounds. The spawning ground was located within a restricted area where bathymetric lines curve towards a shallow area. Adult fish usually occur in the Japan Sea Proper Water (<1 °C), but spawners gathered just below the surface mixing layer where water temperature was 5–10°C. Hence, it was thought that the flounder spawn at the upper tolerable water temperature limit (i.e. the shallowest accessible depth) to release their offspring into the surface layer.     

Spawning patterns provide further evidence for multiple stocks of sardine (Sardinops sagax) off eastern Australia

Previous studies have suggested that sardine, Sardinops sagax, off eastern Australia spawns across its entire range when habitat conditions are suitable. However, recent studies have suggested that separate sub‐populations and spawning groups may occur in the region. Spawning patterns off eastern Australia were investigated using data collected during nine ichthyoplankton surveys conducted between 1997–2015, and adult reproductive data obtained from ad hoc commercial sampling off New South Wales (NSW). The egg surveys covered the known distribution of sardine off eastern Australia and included year‐round sampling in the northern and southern parts of this range. Egg distributions and analysis of gonadosomatic indices identified two spatio‐temporally separate spawning groups; one occurring off southern Queensland to northern NSW during late winter and early spring, and a smaller group off eastern Tasmania to southern NSW during summer. Most eggs were collected from waters 50–90 m deep, with sea surface temperatures of 18–23°C. Additive modelling indicated depth was the most significant factor driving selection of spawning habitat, followed by the interaction of month and latitude. Low egg densities were recorded in waters between 34–37°S, despite conditions within the ranges suitable for spawning. The presence of two spawning groups of sardine off eastern Australia supports recent findings that two sub‐populations occur in the region. Findings of this study will help to optimise the spatio‐temporal extent of future egg surveys and further confirm the need to coordinate future management of each sub‐population among relevant jurisdictions.     

长江鲟亲体对人工模拟产卵底质的偏好性

探究长江鲟(Acipenser dabryanus)自然繁殖对底质环境的偏好性,可为其仿自然人工产卵环境的营造及野外种群重建提供参考。以人工养殖的长江鲟子一代亲本为对象,在直径3.0 m、水深0.8 m的圆形池中铺设长江河道中常见的卵石、砂及人工养殖光滑底质,模拟不同的底质环境,利用发光标记和Ethovision XT行为跟踪技术,研究长江鲟亲鱼对不同底质环境的栖息偏好性和行为活跃性。结果显示,在两两对比的3种实验底质环境中,长江鲟亲本在光滑底质停留时间比57.56%显著长于砂底质42.15%(P<0.05),在光滑底质停留时间比88.63%也显著长于卵石底质10.77%(P<0.05),砂底质中停留时间比75.50%显著长于卵石底质23.89%(P<0.05),表明长江鲟显著喜好停留在光滑底质,其次为砂底质,在卵石底质栖息时间最短,且偏好性无雌雄差异(P>0.05)和昼夜差异(P>0.05)。行为活跃性分析表明,不同底质环境中长江鲟的行为活跃度明显不同,在有卵石底质存在的情况下,其急速游动平均时间要显著高于砂质和光滑底质。结合人工模拟产卵环境中观测到长江...     

葛洲坝下中华鲟产卵场卵苗输移过程的数值模拟

基于水动力学计算的基本原理,采用三维水动力模型及粒子跟踪技术,模拟了中华鲟(Acipenser sinensis)卵苗输移过程。将目前葛洲坝下中华鲟产卵场区域划分为9个子区域,将粒子赋予中华鲟卵粒特征,反演了中华鲟2009年自然繁殖卵苗沿河道输移路线和扩散过程。在划分的9个区域中,区域1、2、5为极有可能的产卵位置。模拟得到的产卵位置、卵输移路径及输移时间与实际监测情况基本一致。模拟结果显示,卵苗输移受天然河道地形和水流流场变化的影响较大。