Environmentally driven forecasts of northern rock sole (Lepidopsetta polyxystra) recruitment in the eastern Bering Sea

Northern rock sole recruitment in the eastern Bering Sea has been hypothesized to (a) depend on wind‐driven surface currents linking spawning and nursery areas, (b) be density‐dependent, and (c) be negatively impacted by cold bottom temperatures over a large nursery area during the first summer of life. A suite of models was developed to test these hypotheses. Data included 32 years of recruitment and spawning biomass estimates derived from a stock assessment model and wind and temperature indices customized to the environmental exposure of age‐0 northern rock sole in the eastern Bering Sea. The predictive ability of the models was evaluated, and the models were used to forecast recruitment to age‐4 for recent year classes which are poorly retained by the standard multi‐species bottom trawl survey gear. Models which included wind and temperature indices performed better than a naïve forecast based on the running mean. The best‐performing model was a categorical model with wind and temperature thresholds, which explained 49% of the variation in recruitment. Ricker models performed more poorly than models without a spawning biomass term, providing no evidence that recruitment is related to stock size. The models forecast higher recruitment for the most recent year classes (2015–2018) than for prior year classes with observed poor recruitment (2006–2013). These environment‐based recruitment forecasts may improve recruitment estimates for the most recent year classes and facilitate study of the effects of future climate change on northern rock sole population dynamics.     

Tropical storm and environmental forcing on regional blue crab (Callinectes sapidus) settlement

Global climate change is predicted to increase the frequency and magnitude of hurricanes, typhoons and other extreme cyclonic disturbance events, with little known consequences for recruitment dynamics of marine species that rely on wind‐driven larval transport to coastal settlement and nursery habitats. We conducted a large‐scale settlement study of the blue crab (Callinectes sapidus) in the Croatan‐Albemarle‐Pamlico Estuarine System (CAPES) in North Carolina, the second largest estuary in the US, during a 10‐yr period that encompassed 35 tropical storms of varying magnitudes and tracks, to determine the effects of hurricane track, wind speed and direction as well as lunar‐associated explanatory variables on spatiotemporal variation in settlement. The results suggest that much of the spatiotemporal variation in blue crab settlement within the CAPES is due to a combination of: (i) stochastic, meteorological events such as the number of tropical storm days during the fall recruitment season (～28% of the monthly variation explained), (ii) the frequency and duration of wind events blowing toward the southwest and, to a lesser degree, (iii) periodic events such as hours of dark flood tide. Tropical storms and hurricanes expand the blue crab nursery capacity of the CAPES. The benefits of hurricane‐forcing to megalopal settlement was dependent upon the storm track, with highest settlement events generally associated with ‘onshore’ storm tracks that made landfall from the ocean and moved inland along a southeasterly/northwesterly path, or ‘coastal’ storms that followed a path roughly parallel to the coastline and were located <300 km offshore of the coast.     

Morphological development and allometric growth of yellowtail kingfish Seriola lalandi V. larvae under culture conditions

Morphological development and allometric growth patterns of Seriola lalandi larvae were assessed to characterize normal growth patterns under culture conditions. Early ontogenetic stages of yellowtail kingfish exhibited an exponential growth in terms of standard length as a function of age. Five development stages were characterized from hatching to the juvenile stage: larval stage I (0–2 days post hatch, dph) with endogenous feeding, characterized by a small yolk sac, unpigmented eyes, primordial finfold surrounding the body and a closed mouth; larval stage II (2–15 dph) characterized by mouth opening, complete pigmentation of eyes and the beginning of the exogenous feeding; subsequently, in the larval stage III (15–25 dph) the posterior tip of notochord of the larvae bended upward and the first rays appeared in fins, concomitant with a change in swimming behaviour; thereafter, larval stage IV (post‐flexion stage; 25–30 dph) began when larvae resembled in morphology to a juvenile organism; however, caudal and dorsal fins were not completely development. Lastly, the juvenile stage was reached 30 dph characterized by a morphology and fin structures similar to those of the adults. Growth and development of structures and organs associated with vital functions such as feeding, sensorial and breathing systems seemed to be more critical previous to 23 dph, which was reflected with a positive allometric growth of head and eyes during this period. The results from this study can be used as a tool‐guide to assess normal development in larval research with S. lalandi to improve existing rearing protocols in hatchery production.     

The effect of environment on puerulus settlement of the western rock lobster (PanuUrus cygnus) in Western Australia

The level of puerulus settlement has proven to be a reliable predictor of the recruitment to the western rock lobster (Panulirus cygnus) fishery three and four years later. It is generally accepted that the early larval stages are moved offshore by wind-driven surface currents. Previous studies have shown that coastal sea level, used as an indicator of the strength of the Leeuwin Current flowing down the west coast of Australia, was positively related to the level of puerulus settling on the inshore reefs after a 9- to 11-month larval life. In this paper a significant relationship is also demonstrated between winter/spring storms, which are usually associated with onshore westerly winds, and the level of puerulus settlement (multiple correlation of 0.83, R¹= 0.68, n = 22). Rainfall from coastal localities was used as an index of the storms. The residuals from this relationship showed a significant positive autocorrelation. The autocorrelation was incorporated into the relationship by using time series analysis with a transfer function model and a first-order autocorrelation (R²= 0.76). The possible relationship between storms and the Leeuwin Current and their effect on the puerulus settlement are considered, and the potential for the environmental variables to bias or obscure the spawning stock recruitment relationship is discussed.     

Growth,settlement and survival of Dicathais orbita (Neogastropoda,Mollusca) larvae in response to temperature,diet and settlement cues

The southern Australian whelk, Dicathais orbita, is a potential candidate for aquaculture, as both seafood and for bioactive compound production. Larval rearing experiments to determine the effects of temperature and diet on the growth and survival of D. orbita larvae under laboratory conditions comprised five different unicellular algal diets of two brown algal species; Isochysis galbana and Chaetoceros muelleri, two green algae; Tetraselmis seucica and Nannochloropsis oculata, and a mixture of all four strains for larvae maintained at 16 and 22°C. Absolute growth, specific growth rate (SGR) and survival were determined regularly. Larvae reared at 22°C on a mixed diet, or brown algae, performed significantly better than those reared on green algal diets alone. Preliminary trials with settlement cues were undertaken on different aged larvae to determine when larvae become competent. An array of natural cues (carrion, Xenostrobus pulex, adult mucus and Ulvella lens), as well as concentrations of KCl was tested. KCl(concentration of 20 mM) induced the greatest settlement, however, no larvae metamorphosed under the conditions provided. This study confirms long‐lived planktotrophic larval development for Dicathais orbita with higher development rates at the higher water temperatures. Further studies will optimize culture conditions and cues for settlement and metamorphosis.     

GABA受体拮抗剂荷包牡丹碱和CGP52432对厚壳贻贝幼虫附着变态的影响

为研究GABA及其受体拮抗剂荷包牡丹碱（GABA_A受体）和CGP52432 （GABA_B受体）在厚壳贻贝幼虫附着变态中的调控作用,实验通过分析厚壳贻贝不同发育阶段幼虫转录组数据获得GABA受体相关蛋白基因（GABARAP）和GABA_B2受体基因(GABA_B2R),发现GABA_B2R在变态前期的眼点幼虫阶段相较于其他阶段幼体显著高表达。通过实时荧光定量PCR验证也得到相似的表达模式,显示GABA_B2R可能参与调控厚壳贻贝幼虫变态发育。药理学实验结果显示,10^-4 mol/L GABA对厚壳贻贝幼虫的变态具有诱导活性（27.2%±3.0%）。在拮抗剂实验中,10^-6～10^-4 mol/L荷包牡丹碱和CGP52432均显著抑制了厚壳贻贝幼虫变态,且抑制作用随浓度升高而增强。实验还发现GABA及其受体拮抗剂都抑制了厚壳贻贝幼虫的游泳行为。研究表明,GABA_A或GABA_...     

Effect of temperature on the development, growth, survival and settlement of green mussel Perna viridis (Linnaeus, 1758)

The effect of temperature on the development, growth, survival and settlement of Perna viridis was studied under controlled conditions to provide information needed for the development of commercial hatchery technology for green mussel P. viridis. Total mortality of the larvae occurred after 24 h at temperatures of 33°C and 35°C. At 24°C, larvae took longer to settle than at temperatures of 27°C, 29°C and 31°C. For optimum larval development (8–13 h), growth (17.2±0.84 μm day^–1) and survival (55.2±0.84%), a hatchery rearing temperature of 31°C is required. For settlement no significant difference was seen between the percentage settlement at 29°C (49.3±3.34%) and 31°C (45.8±1.76%). However, the process of settlement began and ended earlier at 29°C (from 15 to 18 days) than at 31°C (from 18 to 20 days). Thus for larval settlement a temperature of 29°C is recommended.     

Simulation of the impact of climate change on the egg and larval transport of Japanese anchovy (Engraulis japonicus) off Kyushu Island,the western coast of Japan

In order to investigate the impact of climate change on egg and larval transport of Japanese anchovy (Engraulis japonicus) off Kyushu Island western Japan, we conducted particle‐tracking simulations on transport success/failure to fishing grounds from 1960 to 2007. The modeled transport success since the mid‐1990s increased and decreased in the offshore and coastal zones, respectively, compared with the 1960s and 1970s. The estimated northward shift of the spawning ground and weakened Tsushima Warm Current contributed to increase in modeled transport success to the offshore zone. Conversely, the weakening trend of the modeled onshore current in the Goto‐Nada Sea combined with the northward shift of the spawning ground resulted in unsuccessful larval transport. These results suggest that fluctuations in juvenile and subadult anchovy catches in this area may be attributable to changes in the physical environment. The present study showed that changes in transport success induced by oceanographic fluctuations related to climate change, have the potential to affect anchovy recruitment off the western coast of Japan.     

诱导皱纹盘鲍浮游幼虫附着和变态的物质

根据鲍育苗中常用的6种底栖硅藻氨基酸的组成分析结果,选择15种人工合成氨基酸作为诱导物质,进行鲍浮游幼虫附着、变态的影响实验,发现天冬氨酸组附着率最高,谷氨酸组次之,但均略低于底栖硅藻组,明显高于对照组。变态率实验,天冬氨酸和谷氨酸组结果基本一致,均略高于底栖硅藻组,明显高于对照组。不同氨基酸浓度对附着、变态的影响实验结果表明:无论是天冬氨酸还是谷氨酸,实验浓度为10-5mol·L-1组的附着率和变态率最高。     

养殖密度对毛蚶幼虫生长及存活的影响

为探讨毛蚶(Scapharca subcrenata)幼虫养殖的最佳密度,本研究设定了5个不同的放养密度(2、5、8、14、20 ind/m L),养殖实验从D型幼虫阶段一直持续到幼虫完成附着变态。实验结果表明,随着放养密度的增加,水体氨氮浓度、亚硝酸盐浓度显著升高(P0.05);幼虫密度为20 ind/m L时,分别达到最大值0.089 mg/L和0.008 mg/L。溶解氧浓度则随幼虫密度的增大呈现下降的趋势,幼虫密度达到14、20 ind/m L时,显著低于其他密度组(P0.05)。幼虫的生长速率随放养密度的增加显著下降,5~8 ind/m L为幼虫最佳生长密度。幼虫的存活率也随着放养密度的增加显著下降(P0.05),当幼虫的放养密度为20 ind/m L时,存活率仅为35%。放养密度为8 ind/m L时,幼虫的附着密度最大,且在附着基下层的附着密度显著高于中层和上层(P0.05)。同时,随着放养密度的增加,幼虫附着变态的时间被延长,附着变态规格也显著减小(P0.05)。因此,综合考虑各种要素,规模化苗种生产中幼虫的培育密度控制在5~8 ind/m L较为适宜。     

G-蛋白偶联受体与信号通路对紫贻贝幼体附着变态的调控作用

为了阐明紫贻贝Mytilus galloprovincialis幼体附着变态的内在机理,在天然诱导物-微生物膜的诱导参照下,通过使用G蛋白偶联受体（GPCRs）与信号通路的活化剂与抑制剂初步研究了其对该种幼体附着变态过程中调控作用。结果显示,GPCRs活化剂Gpp[NH]p与抑制剂GDP-β-S没有诱导和抑制活性,表明可能非GPCRs的其他细胞反应/过程参与了M. galloprovincialis幼体的附着变态。腺苷酸环化酶/环腺苷酸（AC/cAMP）信号通路相关、理论上具有诱导活性的6种神经性试剂,除了磷酸二脂酶抑制剂（IBMX）外,其它的在10-8-10-3 M浓度下48 h、72 h后都没有活性,并且高浓度下表现出较高的神经性药物毒性。IBMX仅在10-4 M 浓度72 h后呈现出一定的诱导活性,但是与微生物膜48 h就具有非常高的活性相比显著性较低且时间滞后。磷脂酰肌醇/二酰基甘油/蛋白激酶（PI/DAG/PKC）信号通路相关的2种活化剂48 h、72 h均无诱导活性,但是其抑制剂H-7在10-6 M的低浓度下48 h后表现出显著性的抑制效果,72 h后效果丧失,抑制浓度上升到10-5 M。以上活性浓度与作用时间两个方面的结果明确表明了PI/DAG/PKC信号通路可能参与调控M. galloprovincialis幼体的附着变态,而AC/cAMP信号通路可能作为次要通路,或者由于所用神经性试剂的毒性造成的一种实验假象。本研究有助于推进该品种的发育生物学研究以及通过切断信号通路实现生物污损防治技术的开发。     

Optimum temperature and food-limited growth of larval Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) on Georges Bank

We estimated recent growth of Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) larvae collected on the southern flank of Georges Bank in May 1992–94 from the ratio of RNA to DNA (R/D) and water temperature. Growth of both species increased with water temperature to about 7°C and then decreased. The highest growth rates were observed in May 1993 at water temperatures around 7°C. These data confirm an earlier observation of comparable temperature optima for growth of Atlantic cod and haddock larvae in the north‐west Atlantic. Comparisons of field growth rates and temperature optima with data for larvae cultured at high temperatures and prey densities in the laboratory suggest that growth may have been food‐limited at higher temperatures on Georges Bank. Given that 7°C is the long‐term mean water temperature on the southern flank in May and that climate models predict a possible 2–4°C rise in water temperatures for the western North Atlantic, our findings point to a possible adverse effect of global warming on Atlantic cod and haddock.     

Effects of temperature and salinity on the survival and development of mud crab, Scylla serrata (Forsskål), larvae

The combined effects of temperature and salinity on larval survival and development of the mud crab, Scylla serrata, were investigated in the laboratory. Newly hatched larvae were reared under 20 °C temperature and salinity combinations (i.e. combinations of four temperatures 25, 28, 31, 34 °C with five salinities 15, 20, 25, 30, 35 g L⁻¹). The results showed that temperature and salinity as well as the interaction of the two parameters significantly affected the survival of zoeal larvae. Salinity at 15 g L⁻¹ resulted in no larval survival to the first crab stage, suggesting that the lower salinity tolerance limit for mud crab larvae lies somewhere between salinity 15 and 20 g L⁻¹. However, within the salinity range of 20–35 g L⁻¹, no significant effects on survival of zoeal larvae were detected (P>0.05). The combined effects of temperature and salinity on larval survival were also evident as at low salinities, both high and low temperature led to mass mortality of newly hatched larvae (e.g. 34 °C/15 g L⁻¹, 34 °C/20 g L⁻¹ and 25 °C/15 g L⁻¹ combinations). In contrast, the low temperature and high salinity combination of 25 °C/35 g L⁻¹ resulted in one of the highest survival to the megalopal stage. It was also shown that at optimal 28 °C, larvae could withstand broader salinity conditions. Temperature, salinity and their interaction also significantly affected larval development. At 34 °C, the mean larval development time to megalopa under different salinity conditions ranged from 13.5 to 18.5 days. It increased to between 20.6 and 22.6 days at 25 °C. The effects of salinity on larval development were demonstrated by the fact that for all the temperatures tested, the fastest mean development to megalopa was always recorded at the salinity of 25 g L⁻¹. However, a different trend of salinity effects was shown for megalopae as their duration consistently increased with an increase in salinity from 20 to 35 g L⁻¹. In summary, S. serrata larvae tolerate a broad range of salinity and temperature conditions. Rearing temperature 25–30 °C and salinity 20–35 g L⁻¹ generally result in reasonable survival. However, from an aquaculture point of view, a higher temperature range of 28–30 °C and a salinity range of 20–30 g L⁻¹ are recommended as it shortens the culture cycle.     

Effect of Bacillus subtilis on growth development and survival of larvae Macrobrachium rosenbergii (de Man)

A feeding experiment was conducted to investigate the effect of Bacillus subtilis bacterium, on larval growth and development rate of Macrobrachium rosenbergii (de Man) during February 28 to April 8, 2005 in University Putra Malaysia hatchery. Newly hatched larvae of M. rosenbergii were reared with two dietary treatments consisting of newly hatched Artemia salina nauplii with B. subtilis (10⁸ cells ml⁻¹), and newly hatched A. salina nauplii without B. subtilis carried out in triplicate in 60‐L aquarium (50 L⁻¹). After trial, the larvae that fed B. subtilis‐treated Artemia naupli were found to have higher survival and a faster rate of metamorphosis than larvae that were fed with nontreated Artemia naupli. There were significant differences between B. subtilis‐treated Artemia naupli and nontreated Artemia diet in larval growth and development rate of metamorphosis (P < 0.05). Larval survival after 40 days was significantly greater (P < 0.05) in the B. subtilis‐treated groups (55.3 ± 1.02) compared with the nontreated groups (36.2 ± 5.02%).     

First studies of embryonic and larval development of Coilia nasus (Engraulidae) under controlled conditions

Herein, we describe the embryonic and larval development stages of Coilia nasus, an anadromous fish that is indigenous to the Yangtze River and the northwest region of the Pacific Ocean. The success of artificial breeding programmes and modern methods of reproduction allowed us to accurately describe the development stages of C. nasus. These stages were recorded using a binocular microscope and a digital camera‐equipped microscope, and histological and scanning electron microscopy observations were also conducted. Development can be divided into four periods: embryonic, prelarval, larval and juvenile. The fertilized eggs were spherical, transparent, non‐adhesives and buoyant, with an average diameter of 0.80±0.10 mm. Complete early embryonic development took place within 40–43 h post hatching, and the new hatchlings were 2.85±0.20 mm long. The mouth openings (0.25–0.35 mm) appeared at day 6 post hatching. Complete metamorphosis took place by day 60, at which time the larvae transformed into juveniles (65±5.8 mm) and attained skin coloration.     

Influence of feeding regime and temperature on development and settlement of oyster Ostrea edulis (Linnaeus, 1758) larvae

Under controlled conditions of food density and temperature, larval performances (ingestion, growth, survival and settlement success) of the flat oyster, Ostrea edulis, were investigated using a flow‐through rearing system. In the first experiment, oyster larvae were reared at five different phytoplankton densities (70, 500, 1500, 2500 and 3500 μm³ μL^?1: ≈1, 8, 25, 42 and 58 cells μL^?1 equivalent TCg), and in the second, larvae were grown at four different temperatures (15, 20, 25 and 30°C). Overall, larvae survived a wide range of food density and temperature, with high survival recorded at the end of the experiments. Microalgae concentration and temperature both impacted significantly larval development and settlement success. A mixed diet of Chaetoceros neogracile and Tisochrysis lutea (1:1 cell volume) maintained throughout the whole larval life at a concentration of 1500 μm³ μL^?1 allowed the best larval development of O. edulis at 25°C with high survival (98%), good growth (16 μm day^?1) and high settlement success (68%). In addition, optimum larval development (survival ≥97%; growth ≥17 μm day^?1) and settlement (≥78%) were achieved at 25 and 30°C, at microalgae concentrations of 1500 μm³ μL^?1. In contrast, temperature of 20°C led to lower development (≤10 μm day^?1) and weaker settlement (≤27%), whereas at 15°C, no settlement occurred. The design experiments allowed the estimation of the maximum surface‐area‐specific ingestion rate  = 120 ± 4 μm³ day^?1 μm^?2, the half saturation coefficient {X_K} = 537 ± 142 μm³ μL^?1 and the Arrhenius temperature T_A = 8355 K. This contribution put a tangible basis for a future O. edulis Dynamic Energy Budget (DEB) larval growth model.     

盐度对紫海胆受精、胚胎发育、幼体生长、摄食和变态的影响

为研究盐度对紫海胆受精、孵化、胚胎发育、浮游幼体生长发育、摄食和变态的影响,本研究采用实验室培养幼体的方法,设置了不同盐度(15、20、25、30、35和40)的水体,对紫海胆的胚胎和浮游幼体进行实验。结果显示,紫海胆在盐度20～35范围内的受精率超过95%,但在盐度15和40下无法受精;盐度30下胚胎发育最快,孵化率显著高于其他盐度,为89.8%;浮游幼体期适宜盐度为25～35,最适盐度为30,盐度20和40下幼体仅能发育至八腕幼体Ⅰ期,而盐度15下幼体发育受抑制,一直停留在四腕幼体阶段,7 d后死亡;盐度为15～40时的八腕Ⅳ期幼体在72 h的变态率超过21.4%,其中盐度30下幼体变态率最高,为54.7%,且变态速率最快,能在24 h时出现稚胆。浮游幼体在盐度35时前侧腕和口后腕生长最快,胃面积在盐度30时最大,摄食率在盐度30时最大。研究表明,盐度对紫海胆的早期发育有较显著的影响。本研究能够为紫海胆人工育苗培育提供基础资料。     

Variation in the distribution of ocean shrimp (Pandalus jordani) recruits: links with coastal upwelling and climate change

In this analysis, an atypical northward shift in the distribution of age‐1 ocean shrimp (Pandalus jordani) recruits off Oregon in 2000 and 2002–2004 was linked to anomolously strong coastal upwelling winds off southern Oregon (42°N latitude) in April–July of the year of larval release (t?1). This is the first clear evidence that strong upwelling winds can depress local recruitment of ocean shrimp. Regression analysis confirmed a long‐term negative correlation between log_e of ocean shrimp recruitment and April sea level height (SLH) at Crescent City, California, in the year of larval release, for both northern and southern Oregon waters. The regional pattern of ocean shrimp catches and seasonal upwelling winds showed that, although the timing of the spring transition as reflected in April SLH drives ocean shrimp recruitment success off Oregon generally, the strength and consistency of spring upwelling limits the distribution of large concentrations of ocean shrimp at the southern end of the northern California/Oregon/Washington area. A northward shift in 1999 and 2001–03 in the northern edge of this ‘zone of maximum upwelling’ is the likely cause of the weak southern Oregon recruitment and resulting atypical distribution of ocean shrimp observed off Oregon in 2000 and 2002–04, with a return to a more typical catch distribution as spring upwelling moderated in subsequent years. It is noted that a northward shift in the conditions that produce strong and steady spring upwelling winds is consistent with many predictions of global climate models under conditions of global warming.     

Differing environmental drivers of settlement across the range of southern rock lobster (Jasus edwardsii) suggest resilience of the fishery to climate change

Temporal and spatial trends in settlement of the southern rock lobster, Jasus edwardsii, were examined to identify the influence of environmental variables over different spatial scales. Settlement data were collected from 1994 to 2011 along the Southern Australian and New Zealand coasts. We identified common settlement trends at a regional scale (100–500 km): the magnitude of settlement at sites from South Australia (SA) and Victoria (VIC) were similar, but different to sites in Tasmania (TAS). In New Zealand, three spatial regions were identified: northern (NNZ), middle (MNZ) and southern regions (SNZ). Higher settlement in SA, VIC and MNZ occurred in years with higher rainfall and storms in spring and El Niño conditions. In TAS and SNZ, higher settlement occurred during La Niña conditions. These results suggest that settlement over regional scales is modulated by oceanic processes, but outcomes vary between regions. At a local scale, a higher wave period and wind relaxation were relatively more important than the sea surface temperature (SST) in SA and VIC. In TAS, the current velocity also influenced the strength of settlement. However, much of the local settlement variability was not explained by the models suggesting that settlement in J. edwardsii is a complex process where larval behaviour, biological factors and oceanographic processes interact over different scales. The apparently complex processes affecting settlement showed that environmental conditions that reduced settlement strength in one region of the fishery often increased settlement strength in other regions. This could provide resilience to climate change at the stock level.