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This study investigates the ovarian development, spawning patterns, maturity size and fecundity of the goby Glossogobius giuris–a commercial fish in the Vietnamese Mekong Delta–based on the data analysis of 659 individuals. Specimens were caught using trawl nets from four sites representing freshwater (Cai Rang, Can Tho) to salinized regions in the dry season (Long Phu, Soc Trang), and brackish water regions (Hoa Binh, Bac Lieu and Dam Doi, Ca Mau) over the 12 months of 2020. Histological analysis showed that it was a multi-spawner as different stages of oocytes appeared in mature ovaries. The fish could spawn throughout the year, with a peak in April at the freshwater region and in September at salinized and brackish areas as mature ovaries appeared monthly during the studied period and gonadosomatic index displayed the highest value in April and in September, respectively. This goby’s primary egg releasing time tended to be regulated by salinity changes over the four sampling sites. Likewise, size at first maturity of this species could be related to the salinity variation as this value was the longest in freshwater (6.14 ± 0.17) and the shortest in the salinization region (4.82 ± 0.66). Batch fecundity is measured at 5,118–100,003 eggs/female and related to fish length and weight (r2 > 0.76). Findings can be useful for the development of fish conservation strategies and artificial reproducing studies.

Spawning in marine bivalves is a great energy-demanding process, and it often results in lethal and sublethal stresses during the post-spawning period, including depressed immune capacity. The blood cockle Tegillarca granosa (Linnaeus, 1758) distributes widely in silty-mud tidal flats on the south coast of Korea, and they spawn in late summer. To understand the impacts of spawning on immune parameters, we analyzed the total hemocyte count (THC), hemocyte mortality, phagocytosis capacity, and reactive oxygen species (ROS) production of T. granosa in pre-, and post-spawning condition using a flow cytometer. Histology indicated that the blood cockles occurring on the south coast of Korea ripe and ready to spawn in July, and they spawned in August and September. The THC in the blood cockle hemolymph declined from pre-spawning (1.2 × 108 cell mL−1) to post-spawning (0.9 × 108 cell mL−1), possibly due to the spawning stress and the massive infiltration of hemocytes in the gonad to phagocytose and resorb the residual gametes during the post-spawning period. The hemocyte mortality increased linearly from August (4.1%) to November (9.1%), as the histology revealed that the blood cockle completed spawning, and they resorbed the relict gametes. The granulocyte phagocytosis capacity declined dramatically from July (12.7%) to September (6.0%), when the cockles were engaged in active spawning. The flow cytometry revealed that the production of reactive oxygen species (ROS) from the granulocytes and the erythrocytes type II increased linearly from August (0.8–0.9 × 105 A U.) to December (2.1–2.8 × 105 A U.), which may cause stresses at a cellular level during this period. As the data indicated, spawning is a stressful activity inducing depressed immunological capacities in the blood cockles.

La Trobe University Faculty of Science, Technology and Engineering Murray Darling Freshwater Research CentreMDFRC item.Knowledge of the biology of native fishes of the Murray-Darling Basin is based largely on studies conducted under hatchery conditions and on a limited number of recreationally important species. From observations that increases in water level in aquaculture ponds initiate spawning in some species, and from limited studies of wild fishes and studies in overseas floodplain river systems, a perception has emerged of the importance of flooding and the flood plain in the life cycles of Murray-Darling fishes in general. However, there is little confirmatory evidence of the use of temporary floodplain habitats by larvae, juveniles or adults. The significance of in-channel habitats, especially for rearing, has received little attention. Murray-Darling fish species can be placed into three life history modes, based mainly on spawning style and time and developmental intervals of larvae at first feeding. Fish in each group may be able to take advantage of floods if the timing is right and prey are plentiful, however, the larvae of some species are able to recruit under non-flood conditions within the main river channel. This forms the basis of the low flow recruitment hypothesis, which attempts to explain why some species spawn during the warmest months and lowest flows and how they are able to recruit under these conditions. This hypothesis is then placed in the context of the current state of knowledge of the relationships between flow and the biology of Murray-Darling fishes, specifically cues for spawning, movement and recruitment. The lack of widespread evidence for floodplain use by any life history interval of fish may be due to a paucity of study, however, there are some fundamental factors, such as the predictability of timing and duration of high flow events as well as the lack of coincidence of high flows and high temperatures in some regions of the Basin, which may be important in determining the use of floodplain habitats by fish.

Lamprey are living representatives of the basal vertebrate agnathan lineage. Many lamprey species are anadromous with a complex life cycle that includes metamorphosis from a freshwater (FW) benthic filter-feeding larva into a parasitic juvenile which migrates to seawater (SW) or (in landlocked populations) large bodies of FW. After a juvenile/adult trophic period that can last up to two years, adults return to rivers and migrate upstream to spawn in FW. Therefore, the osmoregulatory challenges anadromous lamprey face during migrations are similar to those of derived diadromous jawed fishes because lamprey osmoregulate to maintain plasma osmolality at approximately one third SW as well. While in FW, lamprey gills actively take up ions and their kidneys excrete excess water to compensate for passive ion loss and water gain. When in SW, lamprey drink SW and their gills actively secrete excess ions (to compensate for salt loading and dehydration). Nevertheless, lampreys diverged from the rest of the vertebrate lineage more than 500 million years ago, which is reflected in similarities and differences in ionocyte (ion transport cell) ultrastructure and distribution as well as tight junctions in epithelia. The current review discusses recent advances in our understanding of ion transport mechanisms of lamprey with a focus on sea lamprey (Petromyzon marinus) due to the large literature on this species. We emphasize key molecular and cellular mechanisms in osmoregulatory organs (i.e., gill, kidney and gut) and provide insight relative to what is known in other fishes and identify areas where more research is needed.

The Cheboygan River, Michigan, is the only tributary to the upper Great Lakes where sea lamprey (Petromyzon marinus) are known to complete their entire life cycle. The Upper and Lower reaches are separated by the Cheboygan Lock and Dam located about 2 km from Lake Huron. In the Upper River, the Pigeon, Sturgeon, and Maple Rivers provide nursery habitat for larval sea lamprey. Burt and Mullett Lakes provide feeding grounds for juvenile sea lamprey. Low levels of immigration from Lake Huron occur when adult sea lamprey bypass the lock and dam. Lampricide treatment in the Pigeon, Sturgeon, and Maple Rivers began in 1966 and 15 treatments have been conducted to date at a combined cost of $435,000 USD per treatment. Treatments may become more difficult due to recent dam removals in the Pigeon (2016) and Maple Rivers (2018) that expanded habitat available to valued fishes and sea lamprey. At present, the landlocked population is less than 200 spawning adults, and those adults are generally smaller and may spawn earlier in the spring than adult sea lamprey from Lake Huron. Frequency of sea lamprey-induced wounding on steelhead (Oncorhynchus mykiss) and northern pike (Esox lucius) in Mullett Lake is less than 5%. Given increasing challenges of lampricide treatment, efforts to test other means of control such as sterile male release technique is on-going. The Cheboygan River represents a microcosm of the Great Lakes and is useful for learning about sea lamprey ecology and testing controls that supplement lampricides and barriers.

Arctic grayling (Thymallus arcticus) is an iconic fish species that is present across the remote subarctic Barrenlands, yet our lack of understanding of their distributional patterns constrains predictions of anthropogenic effects on Barrenland populations. These adfluvial fish rely on seasonal lake-stream connections to migrate, spawn, and rear. We address knowledge gaps on what Barrenland stream attributes are suitable for rearing young-of-year Arctic grayling. Visual surveys of young-of-year Arctic grayling were conducted in 48 streams near Baker Lake, Nunavut, Canada. Occupancy modeling was used to relate stream habitat and landscape variables to fish presence/absence. The best predictors of occupancy were total area of contributing upstream lakes and landcover (upland/lowland); stream basins with larger contributing upstream lake area and more lowland cover were more likely to be occupied. Results suggest that occupancy reflects reliability of stream connectivity throughout the open water season and across years. The occupancy model developed here can adequately predict stream suitability for young-of-year Arctic grayling using lake area and land classification data that are remotely accessed. This may lessen the considerable financial and logistical constraints of conducting field research on Arctic grayling in the vast Barrenlands and facilitate more directed field programs to inform conservation and mitigation plans.

Anadromous river herring have declined in many parts of their range, leading to fisheries management efforts to help repopulate this species by improving connectivity of rivers and restoring populations by fish transfers. With data lacking on parasites in these species, this study sought to better understand myxozoans across various life stages and habitats in river herring populations in New Jersey, USA. We compared fish from riverine habitats during early-life growth and adults returning to spawn, marine-phase fish, and landlocked Alewife populations. Three myxozoan species were identified in young-of-the-year (YOY) anadromous river herring, including Kudoa clupeidae in the skeletal musculature, Myxobolus mauriensis in the rib cartilage, and an uncharacterized coelozoic myxozoan within the lumen of mesonephric tubules. In YOY river herring, Blueback Herring were 2 times more likely to be infected by K. clupeidae than Alewife (p = 0.019) and in the Maurice River, fish were 4 times more likely to be infected with M. mauriensis than fish from Great Egg Harbor River (p = 0.000) and 11 times more likely than the Delaware River (p = 0.001). Spawning adult river herring were infected with a previously undescribed myxozoan parasite infecting the kidney. Sequencing the 18S rDNA indicated this species is closely related to Ortholinea species. Myxobolus mauriensis and the Ortholinea-like species were absent from marine-phase river herring indicating that infections were linked to river environments occurring during early-life growth and spawning, respectively. No myxozoans were present in landlocked Alewife, showing that similar infections occurring in rivers were absent in lake environments in the region.

Climate change and its associated symptoms, such as warming air temperatures, glacier retreat, reduced snowpack, and increased variability in precipitation, are warming rivers and lakes. Such warming water temperatures threaten cold-water fishes in some regions. For instance, warm water temperatures can kill or harm anadromous Pacific salmon as they migrate upstream to spawning grounds. In this study, we assessed how tributaries, and their relative watershed properties, shape temporal and spatial dynamics of temperatures during the summer months in a salmon migratory river. We focused on the mainstem of the Babine River of British Columbia, an important migratory corridor for steelhead and the five eastern Pacific salmon species, but particularly for sockeye salmon that spawn in stream reaches above the Babine Lake, at the river’s headwaters. We discovered that large glacier- and snowpack-fed tributaries cooled the Babine River by approximately 2 °C over its 96 km length. Different tributaries played different temperature functions. Cooler and more glacierized rivers were associated with a bigger change in temperature between upstream and downstream sites. Understanding how water temperatures change during adult salmon migration, especially within riverscapes on the edge of potentially harmful temperatures, can help inform proactive management options in a warming world.

Salmonids have emerged as important study systems for investigating molecular processes underlying parallel evolution given their tremendous life history variation. Kokanee, the resident form of anadromous sockeye salmon (Oncorhynchus nerka), have evolved multiple times across the species’ pan-Pacific distribution, exhibiting multiple reproductive ecotypes including those that spawn in streams, on lake-shores, and at lake depths >50 m. The latter has only been detected in 5 locations in Japan and British Columbia, Canada. Here, we investigated the multiple origins hypothesis for deep-spawning kokanee, using 9721 single nucleotide polymorphisms distributed across the genome analyzed for the vast majority of known populations in Japan (Saiko Lake) and Canada (Anderson, Seton, East Barrière Lakes) relative to stream-spawning populations in both regions. We detected 397 outlier loci, none of which were robustly identified in paired-ecotype comparisons in Japan and Canada independently. Bayesian clustering and principal components analyses based on neutral loci revealed 6 distinct clusters, largely associated with geography or translocation history, rather than ecotype. Moreover, a high level of divergence between Canadian and Japanese populations, and between deep- and stream-spawning populations regionally, suggests the deep-spawning ecotype independently evolved on the 2 continents. On a finer level, Japanese kokanee populations exhibited low estimates of heterozygosity, significant levels of inbreeding, and reduced effective population sizes relative to Canadian populations, likely associated with transplantation history. Along with preliminary evidence for hybridization between deep- and stream-spawning ecotypes in Saiko Lake, these findings should be considered within the context of on-going kokanee fisheries management in Japan.

Lake sturgeon (Acipenser fulvescens) can migrate long distances to spawn, but many populations currently spawn in systems where the length of accessible riverine migratory habitat has been greatly reduced by dam construction. With the increased prevalence of shortened rivers, focusing on migratory dynamics in short rivers (

Sea-run brown trout (Salmo trutta) have a highly phenotypically plastic life history that allows them to be effective colonizers and competitors in freshwater. This paper documents a previously unknown spawning behaviour in a brackish, tidally influenced estuary 14 km from the mouth of the Vosso River, a major Atlantic salmon- and sea-run brown trout–producing river in western Norway. Putative spawning gravel was observed, and sea-run brown trout deposited eggs that hatched in April. Survival of recruits was high (> 95%) in the tidal spawning gravel. These areas are strongly tidally influenced with a peak of 23.17 psu recorded at the lowest spawning ground. The observation of spawning so far from the river mouth may be unique in such a system with a long estuary but provides important insight into the biology of sea trout. Invasion of pink salmon, also known to spawn in estuaries, may negatively affect the competitive balance of sea trout with other salmonids in rivers where sea trout populations rely on recruitment from these relatively extreme spawning areas. Restoration of estuaries that have been modified by dredging or channelization may be important to ensure quality and heterogenous habitat for sea trout spawning given that haline spawning grounds could contribute to population resilience.

Lake sturgeon Acipenser fulvescens spawn at the base of Kakabeka Falls, a 39 m waterfall on the Kaministiquia River, a tributary to Lake Superior. Access to this historical spawning site can be restricted or delayed due to hydroelectric flow fluctuations that coincide with the A. fulvescens spawning season. The objectives of this study were to determine (a) the necessary flow conditions that facilitate spawning site access; (b) quantity and duration of flow required for successful spawning and dispersal of larvae; and (c) evaluate recruitment of juvenile A. fulvescens in relation to flow. A. fulvescens spawning migrations were tracked using a stationary telemetry receiver that logged the movements of 166 A. fulvescens fitted with radio-transmitters. Unrestricted access to the spawning site was facilitated when spawning flow was controlled at 23 m3 s-1 in 2004 and 17 m3 s-1 in 2006. Fluctuating (0.5-8.5 m3 s-1 ) and delayed spawning flows resulted in restricted and delayed access to the spawning site. Flow duration for successful egg incubation, hatch and larval dispersal was determined by sampling larvae using drift nets and quantified using cumulative temperature units (CTU). Over 10 years, 10,083 larvae were captured between 31 May and 20 July with 97% of the drift occurring prior to 30 June. From the date of first spawning to the end of larval dispersal took an average of 38.6 days, and the mean CTU value was 398.6. In general, a minimum flow of approximately 14.5 m3 s-1 from the date of initial spawning to the accumulation of c. 400 CTU ensured successful hatch and larval dispersal. During the timeframe of this study, recruitment was variable. This study described the complex and variable reproductive life history of A. fulvescens and defined spawning flow requirements ecologically, which can be used to develop operational provisions at hydropower facilities to ensure successful reproduction.

Longterm data on the liver weight, hepatosomatic (HSI) and gonadosomatic (GSI) indices of walleye pollock, Pacific cod and saffron cod are analyzed on Eastern Kamchatka in seasonal aspect and in the course of gonad maturation. Individual values of the indices extensively vary and depend on the fish body length, season and stage of gonad maturity. The dynamics of the HSI is agree to the dynamics of the GSI during the year and depending on gonad maturity. The maximum values of the HSI are typical for walleye pollock and Pacific cod individuals with the gonads of the III stage of maturity. The maximum values of the index in saffron cod are found in mature individuals with immature gonads. The minimum values are demonstrated by the fish with the gonads at the stage of final spawning or of post-spawning recovery. During the annual reproduction cycle males and females of walleye pollock and cod realize different scenarios of spending and accumulating liver fat. Whereas the maximum HSI is observed in the fish with the gonads at the III maturity stage, the minimum values in males are typical for individuals with smelting gonads, and in females – on finishing the spawn. That can be connected to possible feeding for the individual. Liver weight and liver index can increase in males just shortly after finishing spawning, in females that is found only at the stage of post-spawning recovery.

River herring (Alosa spp.) are anadromous fish that enter North American Atlantic coastal rivers and lakes each spring to spawn. Anthropogenic structures such as dams and tide gates serve as physical obstacles that limit river herring access to spawning habitat. This study examined the physical and ecological components affecting herring passage through a tide gate by applying a time-to-event analysis framework to multiple movement behaviors derived from telemetry data. Herring had higher passage success early in the season (78%) than later (16%). Key behaviors that govern passage varied with diel period, tide, and flow direction through the gates. Furthermore, these behaviors shifted as the season progressed, consistent with the hypothesis that predator avoidance may be driving passage failure late in the spawning season.

The present study was conducted to evaluate the effects of dissolved oxygen concentrations on growth, survival and gonadal development of freshwater pearl mussel (Lamellidens marginalis). Twenty adult L. marginalis were exposed to each of the five different concentrations of dissolved oxygen (DO) i.e (T0, no aeration), and T1, T2, T3 and T4 with one, two, three and four air stone aerators, respectively in fifteen glass aquaria each containing 10L of pond water. DO concentrations were significantly higher in all the treatments compared to the control but there were no significant differences among the treatments. There were significant differences in the growth and survival rates between control and treatments. The relative growth rates (%) were significantly higher in the highest oxygen concentration (T4) compared to other treatments. The survival rate was zero in control (T0), whereas it was 66.67%, 70.00%, 71.67% and 73.33%, respectively for T1, T2, T3 and T4. On day-30, oocytes in T0 were found to be smaller in size, with developing acini and no previtellogenic oocytes; whereas in T1, T2, T3 and T4, previtellogenic oocytes and larger acini were evident. On day-60, vitellogenic oocytes along with few under-developed oocytes started to detach from the acini walls, as well as some already started migration to germinal duct on day-90. This indicates that ovaries of all the treatments were ripe and were ready to spawn between day-60 and -90. On day-30, secondary spermatocytes were observed in testicular acini in case of T0, whereas more developed and dense spermatids were evident in T1, T2, T3 and T4. These results indicate that testes were in late development stages in T0, whereas they were ripe in all the treatments. The current findings indicate that hypoxia slows down growth, reduces survival rate and retards development of reproductive organs in L. marginalis.

Population level biodiversity is critical for preventing extinction in endangered populations. Oncorhynchus nerka in the Snake River Basin have exhibited diversity losses as populations have become extirpated and federally listed as endangered. Efforts to restore O. nerka in the Snake River Basin have focused on preserving local populations, however, there has been no detection of native O. nerka in Pettit Lake. Pettit Lake O. nerka were reintroduced from a non-native kokanee stock originating from Lake Whatcom, WA, and a Sockeye Salmon population was established from Redfish Lake captive broodstock releases. However, recent genetic analyses detected an unexpected signal in Pettit Lake. This study examines genetic variation of Pettit Lake O. nerka in comparison to possible source populations. We used a single nucleotide polymorphism panel developed for Columbia River Basin O. nerka stock identification to determine the origin of Pettit Lake O. nerka. We found that Pettit Lake supports a population resulting from introgression between non-native kokanee and Redfish Lake Sockeye Salmon. Overlap of spawn timing has allowed mixing of these two shoal spawning populations and led to a gradual decrease of the previously predominant non-native kokanee genetic signature. While propensity and timing of emigration seems to remain unaffected by hybridization, the introgressed population displayed longer travel times and later arrival to dams when compared to native Sockeye Salmon in the region. The long-term survival of this Evolutionary Significant Unit is dependent on native diversity thus, O. nerka conservation management must monitor out-of-basin genetics and introgression in the recovery area.

For oviparous animals such as amphibians, the presence or absence of conspecifics can influence site selection, with each life history stage potentially influencing the decision-making process in a different manner. In the present study, we tested the effect of conspecific life history stage on oviposition site selection in the sandpaper frog, Lechriodus fletcheri. We quantified preferences for spawning in pools that were unused by conspecifics, as well as pools with conspecific spawn or tadpoles present, or both. The study included two ecological contexts: a system of naturally occurring breeding pools and a field experiment with 40 artificial pools that controlled for habitat variation. Mothers preferred to oviposit in pools that already contained conspecific spawn, despite the likelihood of intense resource competition upon offspring hatching. This could be due to the potential benefits obtained by providing offspring access to a significant nutrient supply upon hatching via cannibalism of conspecific tadpoles and might be an important adaptation for completing tadpole development in highly ephemeral and resource-limited pools prior to desiccation. In contrast, mothers avoided ovipositing in pools with conspecific tadpoles, a probable adaptation to avoid their own offspring from becoming victims of cannibalism themselves prior to hatching. Such nuances in the effect of conspecific presence on offspring survival highlight the often complex decision-making process that amphibians need to make when selecting oviposition sites, as well as the influence cannibalism can have on the evolution of reproductive behaviour.

Black Amur bream (Megalobrama terminalis), a dominant species, resides in the Pearl River basin, known for its high plasticity in digestive ability. During spawning season, M. terminalis individuals with large body size and high fertility undergo a spawn migratory phase, while other smaller individuals prefer to settlement over migration. It is well known that gut microbial community often underpins the metabolic capability and regulates a wide variety of important functions in fish. However, little was known about how the gut microbiomes affect fish breeding migration. To investigate the variations in the gut microbiome of M. terminalis during the migration, we used high‐throughput 16S rRNA gene sequencing to reveal the distinct composition and diversity of the whole gut microbiome of migrated and nonmigrated population during period of peak reproduction, respectively. Our results indicated that nonmigrated population in estuary had a higher alpha diversity than that of migrated population in main stem. Additionally, an obvious abundant taxa shift between the gut microbiota community of nonmigrated and migrated M. terminalis was also observed. Change of dominant gut taxa from nonmigrated to migrated population was thought to be closely related to their degradation enzymes. Our results suggested that amino acid metabolism and lipid metabolism in migrated population were higher than that in nonmigrated population, providing a line of evidence for that M. terminalis change from partial herbivorous to partial carnivorous diet during breeding migration. We further concluded that, in order to digest foods of higher nutrition to supply energy to spawning migration, M. terminalis regulate activities of the gut microbiome and degradation enzymes, considered to be a key physiological strategy for reproduction., Current study is the first demonstration of gut microbiome in Megalobrama terminalis during the breeding migration. Significant differences of gut microbiota communities of M. terminalis between non‐migration and migration group have been found in our research. Gut microbiota of M. terminalis was found not only to aid in digestion, but also to play an important role in its metabolic capacity and endocrine system during the breeding migration.

The article deals with the reproduction of fish. Fish reproduce at different ages. Reproduction occurs at different times in the life of fish. Most fish reproduce by spawning. The spawning conditions of fish are very different. The eggs are fermented in water. Depending on the choice of spawning substrate, fish are divided into 5 ecological groups. Key words: Kura, ecology, caviar, Acipenseriformes, Clupeonella

The economic evaluation of three hormonal preparations: ovaprim, ovulin and carp pituitary extract (C.P.E) in artificial propagation of Heterobranchus longifilis was investigated. A total of twelve brood fishes (nine females and three males) of eighteen months old were used for the experiment. The females were divided into three groups. Each group was induced to spawn with each of the hormones. Pooled sperm from the three males were used to fertilize the eggs obtained from the females. Effects of the hormones on the fecundity was investigated to help address the economic values. The results showed that the cost of inducing 1.20kg female to yield 42.83g, 57.60g, and 35.10g of eggs were ₦480.39, ₦225.00 and ₦175.00, for C.P.E, ovaprim and ovulin respectively. Profitability index for ovaprim, ovulin, and C.P.E was 5.58, 3.44, and 3.92, respectively. Indicating that, cost of production accounted

Many fish spawn in aggregations, but little is understood about the dynamics governing the success of spawning interactions. Here, we evaluate the influence that location of lek-like mating territories has on spawning interactions of Gomphosus varius. We used direct observations of spawning and egg predation events as well as local population counts to compare the rates of spawning, spawning interruptions, and predation on the eggs of G. varius at Finger Reef, Apra Harbor, Guam. We hypothesized that spawning rates would be highest among seaward locations that facilitate transport of pelagic larvae from reefs and that those territories would subsequently experience higher densities of egg predators, egg predation rates, and spawning interruptions. Male spawning success was highly skewed by mating territory location, with holders of the outer, seaward mating territories being more successful than those males holding territories in the middle and inner areas of the aggregation site. Within the outer territories, male mating success was also skewed by location. Egg predation was observed occasionally and increased linearly with bird wrasse spawning frequency. The population densities of egg predators were distributed equally across the study area. Spawning interruptions occurred most frequently within the inner zone of the spawning aggregation due to greater male-male aggression in intraspecific competition for females and territories. This study provides evidence that reef location influences the spawning success, egg predation rates, and spawning interruption rates of fishes that reproduce using lek-like mating territories.

Sockeye salmon that spawn downstream of rearing lakes are an important example of the challenges faced by organisms with complex life histories requiring connectivity in aquatic habitat complexes. Specifically, newly emerged juvenile sockeye salmon must migrate upstream, against the flow of water, if they are to reach lake rearing habitat. Here, we examine the spatial and temporal dynamics of the water velocity landscape and juvenile sockeye salmon movement and condition at increasing distances downstream from the lake outlet of an important sockeye salmon system, the Babine Lake of British Columbia, one of Canada’s largest and most important sockeye salmon rearing lakes. The results of this study indicate that (i) there were seasonal and spatial patterns of water velocities that exceed the ability of juveniles to swim upstream to lake rearing habitat, (ii) higher water discharge was associated with more velocity barriers and potentially with less upstream movement of juveniles, and (iii) juveniles rearing in the lake obtained larger sizes (30% longer and 150% heavier) than those in downstream river habitats. Multiple processes that may be influencing these patterns could include more abundant food resources, lower metabolic demands, or size-selective immigration, emigration, or mortality among habitats. Years and seasons with high discharge may temporarily create one-way, downstream transport routes at lake outlets. Long-term changes in hydrology, perhaps driven by climate variability or land-use change, may control the degree to which lake outlets function as bidirectional travel corridors or one-way travel routes for young sockeye salmon.

Introduction: Embryonic and larval development in sea urchins is highly dependent on maternal nutritional status and on the environmental conditions of the seawater. Objective: To compare the development of Arbacia dufresnii in two different water temperatures and in progeny with varying maternal origins. Methods: We induced A. dufresnii females and males from Nuevo Gulf to spawn, collected the eggs of each female individually (progeny), separated them into two seawater temperatures (12 and 17 °C), and fertilized them. We recorded the percentage of fertilized eggs and embryos per developmental stage according to time, temperature and progeny. We measured larval growth by total length (TL) and midline body length (M) according to time post fecundation (DPF), temperature, and progeny. Results: Temperature did not affect fertilization, but embryo development was faster and more synchronized in the high temperature treatment. The generalized linear models indicate that embryo development depends on a quadruple interaction between the embryonic stage, time (h), seawater temperature and progeny. Larval growth was faster, producing larger larvae at the highest temperature. Larval growth depends on a triple interaction between time (DPF), seawater temperature and progeny. Conclusions: We found a temperature and progeny impact during embryonic and larval development and, in both cases, these factors generate a synergistic effect on developmental timing and larval size. This probably provides a survival advantage as a more rapid speed of development implies a decrease in the time spent in the water column, where the sea urchins are vulnerable to biotic and abiotic stressors. Resumen Introducción: El desarrollo embrionario y larvario de los erizos de mar depende en gran medida del estado nutricional materno y de las condiciones ambientales del agua de mar. Objetivo: Comparar el desarrollo de Arbacia dufresnii en dos temperaturas de agua diferentes y en progenies con diferentes orígenes maternos. Métodos: Indujimos a las hembras y machos de A. dufresnii del Golfo Nuevo a desovar, recolectamos los huevos de cada hembra individualmente (progenie), los separamos en dos temperaturas de agua de mar (12 y 17 ° C) y los fertilizamos. Registramos el porcentaje de óvulos fecundados y el porcentaje de embriones por etapa de desarrollo según tiempo, temperatura y descendencia. Medimos el crecimiento larvario según la longitud total (TL) y la longitud corporal de la línea media (M) de acuerdo con el tiempo en días post fecundación, la temperatura y la progenie. Resultados: La temperatura no afectó la fertilización, pero el desarrollo del embrión fue más rápido y más sincronizado en el tratamiento de alta temperatura. Los modelos lineales generalizados indican que el desarrollo del embrión depende una interacción cuádruple entre el estadio embrionario, el tiempo (h), la temperatura del agua de mar y la progenie. El crecimiento larvario fue más rápido, produciendo larvas más grandes a la temperatura más alta. El crecimiento de las larvas depende de una triple interacción entre el tiempo (DPF), la temperatura del agua de mar y la progenie. Conclusiones: Encontramos un impacto en la temperatura y en la progenie durante el desarrollo embrionario y larvario y, en ambos casos, estos factores generaron un efecto sinérgico sobre el tiempo de desarrollo y el tamaño de las larvas. Esto probablemente proporciona una ventaja de supervivencia, ya que una velocidad de desarrollo más rápida implica una disminución en el tiempo que pasan en la columna de agua, donde los erizos de mar son vulnerables a los factores estresantes bióticos y abióticos.

Mushroom cultivation is an economical biotechnological process for the conversion of various unused lignocellulosic wastes into protein rich food. The present study was conducted to assess the suitability of three different cereal grains viz., bajra (Pennisetum glaucum L.), wheat (Triticum aestivum L.) and maize (Zea mays L.) for spawn production of Macrocybe gigantea (Massee) Pegler & Lod. and further its cultivation on two agrowastes (wheat straw and paddy straw) for assessing biological efficacy. It was observed that among the three cereal grains tested, bajra grains took significantly (P?0.05) less time for spawn development. Moreover, a minimum period of spawn run (16.3 days), highest sporophore yield (343.6g/500g of dry substrate) and biological efficiency (68.7%) were also recorded from substrate bags inoculated with bajra grain spawn. These results suggest the use of bajra grain spawn for quick and successful cultivation of M. gigantea.

In order to explore the change rule of physiological indexes during the aging process of the liquid spawn of Auricularia auricula, this test chooses three species of Auricularia auricula(Hei29, Heiweibanjin and Heiweidanpian), which treasured the activities of antioxidant enzymes, antioxidant substances, membrane peroxidation degree and reactive oxygen concentration during different mycelia age. The conclusion showed that: at the same mycelial age, the vitality of Heiweidanpian was the strongest, Hei29 followed, and Heiweibanjin was the weakest; with the increase of mycelia age, Catalase (CAT) activity, Ascorbic Acid(ASA) content, Malondialdehyde (MDA) content and O2- production rate of the three kinds of Auricularia auricula increased continuously. Among them, ASA content, MDA content and O2- production rate increased significantly, while Superoxide Dismutase (SOD) activity decreased significantly; although the Proline (Pro) content and electrical conductivity of the three kinds of Auricularia auricula showed different trends, which decreased significantly at 14 to 16d and increased significantly at 8 to 10d, respectively, and H2O2 content increased significantly at 12 to 16d. It can be seen that SOD activity, CAT activity, ASA content, MDA content and O2- production rate have significant regular changes during the aging process of the liquid spawn of Auricularia auricula. The quantitative analysis found that when the MDA content is 1.42~1.72 μmol·g-1, the H2O2 content is 3.4~4.3 μmol·g-1 or the O2- production rate is 9.5~12.1 μmol·g-1·min-1, it can be considered Auricularia auricula just started to age or the aging degree is relatively low.

The residence and movement patterns of the marbled flounder Pseudopleuronectes yokohamae were investigated around a spawning ground located off the coast of Nagasaki point, southern Suo Nada, Seto Inland Sea, Japan. Twenty marbled flounder (9 females and 11 males) tagged with ultrasonic transmitters were released on November 29, 2017, before the peak spawning season (peak spawning season: mid–late December), and their distributions were recorded by 15 acoustic receivers until January 21, 2018. Eighteen fish roamed around in the study site or disappeared from the study site but appeared again. The 18 fish then emigrated from the study site by mid-December. The remaining two (1 female and 1 male) of the 20 tagged fish resided until mid-January and continuously roamed around areas of silt–clay to very coarse sand bottom sediments both day and night during the peak spawning season. Movement patterns of marbled flounder may be related to spawning site selection or reproductive behaviors. The fish that emigrated may have roamed around the study site or surrounding areas in order to judge whether to spawn there, but most of them may not have in the study site. In contrast, the remaining two fish may have reproduced within the study site.

Keystone predators can impact many prey species, including those that are endangered. A requisite to assess the impact predators have on different prey populations is to identify the species being consumed in different types of communities, while accounting for possible seasonal variation in consumption. Here we used analysis of North American river otter (Lontra canadensis) scat to assess the impact river otters have on their prey populations, particularly endangered salmonids and migrating birds. We analyzed the prey composition of 1,411 river otter scats collected from 10 sites in Humboldt County, California, between 2011 and 2012. Analysis of prey items in scat placed study sites into four distinct clusters based on diet. Fish, mostly from the families Gasterosteidae, Cottidae, and Pholidae, formed the primary prey component, and crustaceans, birds, amphibians, and insects, also were important components of river otter diet. Salmonids constituted < 5% of overall diet, but river otters consumed the largest percentage of salmon during salmon spawning season at the inland cluster where salmonids spawn. Scat marking intensity varied between clusters and seasons, with the most scats collected in the autumn and the fewest in the winter/spring, except at the inland cluster where the pattern of marking activity was reversed. River otters may be responding to seasonal migrations of endangered and threatened salmonids. Diet surveys of this type are useful for monitoring resource use by top predators in aquatic ecosystems.

Endangerment of fish habitats worldwide is a global problem. Breeding fish in restocking hatcheries is important for bioconservation of many fishes. Analysis of biochemical and hematological parame...

Median timing of reproduction in salmonid populations is generally consistent among years, reflecting long-term patterns of natural selection from characteristics of the local environment. However, altered selection from factors related to climate change or human intervention might shift timing over generations, with implications for the population’s persistence. To study these processes, we modeled median timing of redd (nest) counts as an index of spawning timing by natural-origin Chinook salmon (Oncorhynchus tshawytscha) in the Skagit River system in Washington State, USA. Over the last 2–6 decades, natural-origin salmon have been spawning later by 0.03–0.52 days·year–1, while a naturally spawning group that is influenced by strays from a hatchery has been spawning earlier by 0.19 days·year–1. Trends in the spawning timing of hatchery-origin strays may reflect opposing selection from the hatchery, where egg take for propagation has become earlier by 0.58 days·year–1. As mean August river temperatures have risen over the period of record, hatchery timing trends may be moving in the opposite direction from the plastic or adaptive patterns expressed by natural-origin fish.

Lentinus tigrinus is a wood-decaying species of macrofungi that belongs to family Polyporaceae. This mushroom is known to be edible and with medicinal attributes. In this study, cultivation of different strains of Lentinus tigrinus using rice straw-sawdust based substrate is reported. Results showed that the shortest incubation period was observed in strain 10 (16.60 days), and the longest was noted in strain 1 (40.50 days). However, strain 10 showed the earliest appearance of fruiting initials (20.70 days), and strain 1 had the longest period (44 days). In terms of fruiting body size, strain 6 recorded the widest mean pileus diameter (72.2 mm), and strain 10 had the longest mean stipe length (41.22 mm). Moreover, strain 6 produced the highest yield of 81.83 g and biological efficiency of 16.37%. Interestingly, although they belong to the same species, cultivation phase and fruiting body performance of different strains of L. tigrinus may also vary depending on geographical origin, which is very important to consider in strain selection.

The dynamics of physiological and biochemical parameters of blood and urine in the process of gonad maturation in females of the sterlet × beluga hybrid (Acipenser ruthenus L., 1758 × Huso huso L., 1758) grown using CWSI technology is studied. It is shown that, when this technology is applied, features in functional changes that accompany the gonadogenesis of female hybrids appear, distinguishing them from those of fish from natural populations. At the same time, the direction of the generative exchange aimed at the formation of gametes is generally the same as in females from natural populations. However, the evidence of this process, reflecting its intensity at different stages of gonad development, is not as distinct as in females migrating to spawn. Possible reasons for high levels of the studied physiological and biochemical parameters in blood of females of the hybrid after the end of their artificial wintering are discussed.

This study was carried out to investigate the effects of different substrates and spawn doses on the yield of Pleurotus cornucopiae. In the experiment different spawn doses (1, 2, 3, 4 and 5 %) and five agro-forestry waste viz., wheat straw, paddy straw, sugarcane bagasses, maize straw and saw dust were evaluated for the cultivation of P. cornucopiae. The trial was conducted using completely randomized plot design with three replications. Days to spawn run, average number of basidioma and yield as well as biological efficiency of mushroom were observed. The result of this study indicates that maximum yield (517.33 g/2kg substrate) with a biological efficiency of 86.22 per cent was recorded in wheat straw substrate spawned at the rate of 5 per cent spawn. It was found that minimum (14.00 days) time to spawn run and maximum (7.33) number of basidioma was harvested from wheat straw spawned at the rate of 5 per cent.

The reproductive characteristics of crabs play an important role in their fisheries management. The blue swimming crab Portunus pelagicus is one of the most commercially important crustaceans distributed along the Egyptian Coast; it has a great demand for their esteemed food. The spawning season of P. pelagicus was estimated based on three parameters: the monthly variation in both the maturity stages and in the gonado-somatic index (GSI) beside the histological examination of the ovarian structure. P. pelagicus was capable of continuous spawning throughout the year, where the mature stage was found to be distributed along the whole year indicating that crabs may be spawn at different times. P. pelagicus spawning mainly takes place twice, January-February (winter period) and June- August (summer period). As the monthly variation in GSI exhibit two distinct peaks in winter and summer. The mean size at which P. pelagicus became potentially reproductive (Lm50) was estimated to be 9.32 cm CW for males and 8.45 cm CW for females. To achieve the sustainable utilization, it is recommended to increase the minimum fishing size of this crab to at least 11.0 cm CW to protect the stock biomass and allow young individuals to reach the suitable marketable size.

In response to perceived, but unknown variation among the size selection of narrow-barred Spanish mackerel (Scomberomorus commerson) by artisanal gillnetters off Iran, and the need for such data to control exploitation as a precursor to balanced harvesting, the effects of two common mesh sizes (130 and 140 mm stretched mesh opening made from multifilament twine) on catches were investigated over one fishing year (nine months encompassing autumn to spring). Both mesh sizes mostly caught S. commerson at fork lengths (FL) larger than mean sizes at maturity (>67 cm), with the mean size selection incrementally increasing in the 130-mm mesh gillnet from autumn, and especially during spring. The greater selection occurred concurrent with an increasing condition factor (CF) among S. commerson, which typically spawn in late spring/early summer. Conversely, the relative size-selection of the 140-mm mesh gillnet decreased in spring, attributed to increasing CF precluding the capture of larger fish. Such seasonal variation in size selection might be countered by increasing mesh size to ~145 or 150 mm in spring. However, the existing 140-mm mesh might positively affect stock biomass by allowing larger, more fecund fish to avoid capture during spawning. The data support the strong influence of biological and environmental factors on gillnet size selection, which might also extend to other migratory, pelagic species.

Understanding the extent and distribution of population structure and genetic connectivity of fisheries targets are crucial for informing management. This study uses population genomics to examine patterns of genetic structure of the market squid (Doryteuthis opalescens), one of the most important commercially harvested species in California. Data from 662 single nucleotide polymorphism (SNP) loci from a total of 149 individuals representing five monthly sampling groups (May–September 2014) in the Northern (Monterey) and Southern (Southern California) regions of the fishery (n = 8) revealed no significant genetic differentiation between regions (FST = 0.008, p > 0.05, FCT = − 0.006, p > 0.05). However, discriminant analysis of principal components and pairwise comparisons of genetic differentiation revealed unexpected complex patterns of fine-scale population structure over time. These results suggest the existence of smaller potentially genetically varied micro-cohorts that continually spawn in California, as opposed to the prevailing notion that spawning occurs in two asynchronous peaks in the Northern and Southern regions of the fishery, with important implications for fisheries management.

Anadromous salmonid fishes frequently exhibit strong geographic population structuring. However, population genetic differentiation of Atlantic salmon (Salmo salar) at fine geographic scales differs across equivalent spatial extents in different regions. So far, fine-scale genetic differentiation has not been assessed in rivers of the Baltic Sea, a region that contains an evolutionarily distinct Atlantic salmon lineage. Thus, Baltic salmon are currently managed on the river level, without focus on potential genetic structure and diversity within rivers. Here, we used microsatellites to characterize the genetic structure of wild juvenile salmon sampled throughout the interconnected, northern Baltic Tornio and Kalix Rivers. We found genetic differentiation within the two rivers, but not between them: salmon in the upper reaches differed from individuals in the lower reaches, regardless of river system. Further, examining smolts migrating from the river to the sea and adults returning from the sea to spawn, we found an association between the genetic structure and seasonal migration timing. Out-migrating smolts genetically assigned to upper river reaches were older and tended to reach the sea later in the season than smolts from the lower reaches. In contrast, mature adults originating from the upper reaches returned to the river early in the season. Our observation of genetic population structuring between downstream and upstream reaches of the large Tornio and Kalix rivers, and its association with migration timing, implies that careful temporal management of the northern Baltic fisheries would help to preserve the diversity and sustainability of the wild salmon stocks of these rivers.

The movement patterns of native migratory fishes may reflect different selection pressures in different environments that are associated with predictable patterns of temperature and discharge. Spatial and temporal variability in the movement patterns of adult Coho Salmon Oncorhynchus kisutch were explored with data that were collected from the Umpqua River basin, Oregon, focusing on two points in their return migration: (1) main-stem midriver migration timing of adult Coho Salmon as they pass Winchester Dam, Oregon, and (2) adult spawn timing in tributary streams of the Smith River. Main-stem migration of Coho Salmon as they pass Winchester Dam began 7 to 15 d after peak annual water temperature, when mean daily temperatures cooled to 18°C, but before the increases in discharge that are associated with autumn rains. Although migration timing appeared to be strongly related to river temperature, spawn timing of Coho Salmon in tributaries of the Smith River subbasin appeared to respond to a combination of both discharge and temperature thresholds. Spawning occurred after initial annual peak discharge events and when stream temperatures fell below a threshold of 12°C. These results directly inform water conservation and protection planning for environmental flow criteria and thermal ranges during migration and spawn timing of imperiled Coho Salmon in the Oregon Coast Range.

Tenualosa Ilisha (Clupeidae) is the most important single species and national fish of Bangladesh. It accounts for more than half of the total marine catches and about 12-13% of total fish production and about 1.0 percent of GDP. Absence of small females and large males and transitional gonads of the histological data proved Tenualosa toli and T. macrura (Clupeidae) changes their sexes at the end of the first year and spawn as females in the second year. T. toli Spawn in the middle reaches of estuaries and females deposit all their eggs at once while T. macrura spawn throughout the year in Sumatra but in Sarawak have a seasonal peak in the NE monsoon (December). The smaller sized T. ilisha are almost all males, a few small functionally female fish are present in Bangladesh water body. Male sex ratio of T. ilisha is less than female sex ratio (1:5.09).

The aim of this study was to evaluate the reproductive traits of the non-inbred and inbred AquaAmérica, GIFT and AquaAmérica × GIFTgenetic groups. Six fish from each genetic group were used (2 females:1 male). Females were examined for the presence of eggs in their mouth at every four days, for 12 weeks. Reproduction occurred in all genetic groups (GIFT: 100%; non-inbred AquaAmérica and AquaAmérica ×GIFT: 75%; inbred AquaAmérica: 50%). Female weight, female standard length, total spawning weight, absolute fecundity, relative fecundity, spawn index and hatching rate did not differ significantly between the genetic groups. However, the non-inbred AquaAmérica variety showed lower values (P

Seasonal aggregations at specific sites are common among some fish species. Experienced fishermen know where and when these aggregations happen, often targeting these spawning sites to increase their catch. This strategy can further contribute to endangering the survival of these species, especially for those already threatened by other forms of pressure. This study contributes knowledge to the spawning aggregation of fish in the north of Mozambique following survey work conducted around Cabo Delgado Province in six coastal villages in 2016, 2017 and 2018. The objectives of the study were 1) to identify the species and sites of spawning aggregation and 2) to determine the timing of spawning aggregations. Data collection consisted of interviews targeting the most experienced fishermen to obtain information on these subjects. The results indicate that out of 124 fishermen interviewed, 59% had knowledge of spawning aggregations. The information collected from fisher interviews revealed that there are at least six spawning locations and at least eight species aggregate to spawn (Leptoscarus vaigensis, Lethrinus harak, Lethrinus nebulosus, Lethrinus obsoletus, Lethrinus olivaceus, Plectorhinchus gaterinus, Plectorhinchus schotaf, Siganus sutor). Only Siganus sutor was reported to spawn in at least one of the fishing areas used by every village. The timing of spawning aggregations most reported by fishermen was during the Kusi (South) monsoon period.

Two of the remaining coregonine species in Lake Ontario, cisco (Coregonus artedi) and lake whitefish (C. clupeaformis), spawn in Chaumont Bay, New York. Larvae co-occur in the spring but are difficult to distinguish morphologically. We applied genetic species identification using microsatellite DNA loci of 268 larvae from known locations in nearshore and offshore habitats in Chaumont Bay to determine the extent of mixing of these species in each habitat. Cisco dominated the larvae (95%) in offshore habitats and lake whitefish dominated (84%) in nearshore habitats, where seven of eight putative hybrids occurred. Habitat segregation between these two species at the larval stage has implications for productivity estimates, as changing environmental conditions may differentially affect shallow and deep waters, larval survival, and possibly subsequent recruitment. Discrimination between cisco and lake whitefish larvae will help to characterize habitat and basic life history needs and to focus research collections. Genetic species identification should be applied to larger samples of larvae to evaluate changes in larval distributions and associations with environmental conditions.

The St. Marys River connects Lake Superior to Lake Huron, comprising the international border between Michigan, United States, and Ontario, Canada. This Great Lakes connecting channel naturally encompasses various habitats including lakes, wetlands, islands, tributaries, side channels, and main channels. The St. Marys River Rapids are shallow rock areas with high flow velocities (>1 m/s) in the upper river adjacent to the navigation locks and electric power generating stations, while the Little Rapids are shallow, recently restored rocky areas with lower velocities located about 7 km downstream. The St. Marys River Rapids provide important spawning habitat for several native and introduced fishes, but spawning by lake sturgeon (Acipenser fulvescens) was not previously documented. We sampled for lake sturgeon eggs and larvae in both locations during June and July 2018–2019 using weekly benthic egg mat lifts and overnight D-frame larval fish drift nets. Viable lake sturgeon eggs (11 in 2018, 45 in 2019) were collected in the tailrace of a hydroelectric power facility adjacent to the St. Marys River Rapids. Larval lake sturgeon (21 in 2018, 1 in 2019) were collected in the same area as the eggs. Neither lake sturgeon eggs nor larvae were collected at Little Rapids in either year. Our results are the first documentation of successful lake sturgeon spawning and larval drift in the upper St. Marys River. While our observations showed spawning in a human-made tailrace area, the fate of larvae produced here is unknown and warrants further research.

Synthetic hormones are widely used for induced breeding with significant successes. This study compared spawning successes in paradise fish (Macropodus opercularis) using synthetic hormone (Ovaprim) and natural simulation in glass tanks (0.3m x 0.6m). The experiment was conducted in two parts using two males and two females brood fish. The weights of the fish were between 4.0 and 5.0g for the males and 5.0 and 6.0g for the females. For the induced spawning, Ovaprim was injected intramuscularly according to the fish body weight after which they were left to spawn. The group on natural spawning were not induced by any hormone. Hatching of the eggs occurred within 48 hours at a temperature of 28.80C. Total number of eggs obtained by artificial and natural breeding were 430 and 322eggs respectively. Percentage fertilization in artificial breeding was 63.26% while 41.93% was recorded in natural breeding. Fry were raised on compounded diet for 6 weeks. Results showed that artificially bred fish had a higher mean weight gain (2.31 g) and survival rate (48.17%) than those from natural breeding having 2.10 g and 44.26% respectively. The results suggest that artificial breeding using synthetic hormone (Ovaprim) yielded better spawning success and survival rate than natural process. Keywords: Paradise fish, natural breeding, hormone, fertilization, survival

A variety of data needs challenge the successful restoration and management of alosine populations, including information on the migration, mortality, behavior, demographic rates, and distribution of fish, both in riverine and marine environments. Radiotelemetry with gastric‐implanted transmitters has typically been used to answer some of these questions; however, observing alosines over extended periods and in the marine environment has remained beyond the limitations of this technology and implantation technique. To address these issues, we conducted an acoustic telemetry study on American Shad Alosa sapidissima by using surgical implantation methods. We tagged fish during 2015 (n = 46) and 2016 (n = 52) in the Charles River, Massachusetts, an urbanized watershed where American Shad were believed to be extirpated prior to restoration efforts beginning in 2006. Surgical implantation produced rates of in‐river mortality (40% overall) and posttagging fallback (39% overall) that were comparable to those from traditionally used gastric implantation methods. Data from American Shad that were retained for statistical analyses (n = 59) demonstrated that Watertown Dam (at river kilometer 14.3) impeded upstream migration and that New Boston Dam and Locks (at the mouth of the river) delayed postspawn emigration from the river. In total, 49 American Shad were detected outside of the Charles River. The distribution and low number of total detections, despite a large number of nearshore arrays, suggest that American Shad occupy waters farther offshore during their marine phase. American Shad were detected as overwintering on the Scotian Shelf (n = 5) and the Mid‐Atlantic Bight (n = 1). In 2017, 10 of the individuals that were tagged in 2016 returned to spawn, providing the first reported data on total migration timing and migratory behavior free of handling effects. Surgical implantation of acoustic telemetry tags is an effective method that can provide necessary and previously unattainable data on a species of conservation need.

To understand how environmental conditions and reproductive events affect coral energetic status, seasonal variations in lipid and fatty acid profiles of the common scleractinian coral, Acropora millepora, were studied from pre-spawning in November 2009 until post-spawning in November 2010 at Halfway Island (in the Keppel Island Group, Southern Great Barrier Reef, Australia). Seasonal chlorophyll levels, photosynthetically active radiation (PAR), rainfall and water temperature were major drivers of the overall coral lipid profile, and this was particularly pronounced in correlations with the important, high-energy lipid, triacylglycerol. This likely reflected changing food sources and feeding modes (i.e. phototrophy vs heterotrophy), which corresponds to the opportunistic feeding behaviour of corals. Water temperature was also a major influencer of the coral fatty acid profile. In particular, saturated fatty acids correlated positively with water temperature, while polyunsaturated fatty acids correlated negatively, reflecting cell membrane fluidity regulation, which is necessary for coral to tolerate changing temperatures. Spawning and maternal provisioning also proved to be a major driver of change in the coral lipid profile. The mass spawning events in spring for both 2009 and 2010 caused reductions in the important coral egg constituents: wax ester, triacylglycerol, phosphatidylcholine and fatty acid 10:0. Interestingly, lipid accumulation was significantly lower in the 2010 spawn compared to 2009, possibly due to lower PAR and chlorophyll levels, reflecting reduced photosynthetic activity and phytoplankton availability. Regardless, in 2010, resource provisioning to egg production was greater than in 2009, suggesting increased reproductive effort in the face of environmental stress. This study demonstrates the strong influence of opportunistic heterotrophy and autotrophy and maternal provisioning on the coral lipid profile. Such information is fundamental to understanding the environmental and biochemical processes underlying coral health and predicting how anomalous events and climate-driven changes will affect coral reef assemblages.

The spawning and well-being of fish in an ecosystem are closely linked to climatic cues, viz., temperature and rainfall. Reduced fitness can affect the reproductive performance and lead to skipped spawning. Benchmarking the threshold fitness required for a fish population to achieve readiness for spawning, and understanding how climatic parameters influence the fitness will aid in predicting the fate of its reproductive success in future climatic conditions. This study determined the threshold condition factor pre-spawning fitness (Kspawn50) at which 50% of the female Channa punctata population can be deemed fit for spawning. The optimal climate within which pre-spawning fitness is attained by this species under Indian climatic conditions was also identified. The study was conducted from June 2015 to September 2016, covering two spawning seasons (June–August) in a Gangetic floodplain wetland of West Bengal, India. The non-parametric Kaplan–Meier method (survival fit) was used for estimation of pre-spawning fitness. “Ready to spawn” females were classified based on binary coding of the gonadal maturity stages. The thermal and precipitation range within which spawning fitness is achieved was identified by using the locally weighted smoothing technique. Female C. punctata pre-spawning fitness (Kspawn50) ranged from 1.26 to 1.39 with an estimated median of 1.29 units. Temperatures between 29 and 32 °C and rainfall above 100 mm were conducive to attaining the requisite pre-spawning fitness in C. punctata. This is the first study benchmarking the pre-spawning fitness and optimal climate for C. punctata. Understanding spawning requirements can inform the climate change–induced impacts on reproductive plasticity and evolutionary adaptations of snakeheads in the Ganga river basin.

Pinfish, Lagodon rhomboides, and pigfish, Orthopristis chrysoptera, are popular marine baitifsh used throughout the southeastern United States. Well‐defined methods exist for closing their life cycles in captivity and are being used for commercial aquaculture efforts for each species. Multiple spawning hormones have been effective for spawning induction for both species. Evaluations of a type II gonadotropin‐releasing hormone (cGnRH IIa) have proven it effective for induced spawning in channel catfish, and it has been proposed to be an effective hormone for induced spawning in other species. Four dosages (25, 50, 100 and 200 μg/kg) of cGnRH IIa for spawning induction along with a negative (saline at 0.5 ml/kg) and positive control (Ovaprim® at 0.5 ml/kg) treatment were evaluated for both species. Pinfish and pigfish responded to every cGnRH IIa tested, with up to nine viable spawns collected from pigfish at 100 μg/kg and up to five viable spawns collected from pinfish at 200 μg/kg. The amount of sinking eggs spawned, egg and larval size, and hatching success and survival to first feeding differed significantly for pigfish. Total egg production, fecundity, egg and larval size, and hatching success and survival to first feeding were significantly different for pinfish. While effective for spawning induction in both species, there may be some decrease in spawn quality associated with cGnRH IIa, at least for pigfish. Future research directed towards understanding the potency and physiological reactions caused by cGnRH IIa will help corroborate findings of higher egg output and reduced egg and larval quality.

Octopus fisheries have prospered in many areas of the world ocean over the last six decades. Despite degradation and overexploitation of Chinese coastal ecosystems, octopus has become a stable Chinese domestic fishery species. Among the octopus species in the Bohai and Yellow, East and South China Seas, Amphioctopus fangsiao (d’Orbigny [in Ferussac & d’Orbigny], 1839–1841) plays an increasingly important role both economically and ecologically. However, no systematic research has been conducted on its biology and population dynamics in the China Seas. In this study, we characterized the growth and distribution of A. fangsiao in Haizhou Bay, Yellow Sea based on four years of trawl survey data. As the results, A. fangsiao is characterized by allometric growth and an overall sex ratio of 0.97 with a slight male bias. Small octopus can be observed through a whole year, suggesting that A. fangsiao may have an extended or continuous spawning season. A. fangsiao may migrate short distances along with seasonal changes and coastal currents, considering they overwinter in the offshore water and spawn in the inshore water. In addition to fishing pressure, annual variations in the population structure and biomass appeared to be influenced by ambient water temperature. These results provide basic biological information for a better understanding of the population dynamics and the ecological importance of A. fangsiao.

Medicinal mushrooms have bioactive compounds with therapeutic properties. Lion’s Mane Mushroom is found throughout the northern hemisphere in Europe, Asia, and North America. The present investigation was conducted with the aim to determine the effect of organic and inorganic additiveon mycelium growth (spawn) of Lion’s mane mushroom (Hericium Spp.). In the present study organic additive viz. pulses flour (Pigeon pea) and cereal flour (Rice flour) @2% and inorganic additive (MgSo4) were mixed @1% as a supplement with wheat grains for spawn production of six different strains of Hericium. The results obtained during the present investigation, in the spawn production maximum mycelial growth (90.00 mm) was found in strain He-02 in the organic additive Pigeon pea flour and also in cereal flour (Rice flour) on 20th days, while maximum mycelial growth (90.00 mm) was also found in strain He-02 when Mgso4 was mix in wheat grains for spawn production of six strains of Hericium as inorganic supplements. Based on the results obtained, for spawn production of Lion’s mane mushroom (Hericium Spp.) strains He-02, by organic and inorganic supplementation, Pigeon pea flour and rice flour while in case of inorganic additive Mgso4 would be recommended most effective supplement in wheat grains for strain He-02.