Artificial Spawning Research Articles

Применение искусственных нерестилищ тихоокеанской сельди (Сlupea pallasii) в Тауйской губе Охотского моря, в качестве компенсационных мероприятий для возмещения ущерба водным биоресурсам

An experience on the creation of artificial spawning grounds for Pacific herring
 in Tauyskaya Bay of Sea of Okhotsk in 2014 is presented. A necessary area of
 artificial spawning grounds is calculated based on the volume of the substituted
 damage. It is shown that it is possible to compensate the damage to aquatic living
 resources, caused by economic activity with the suggested method.

PENGARUH EKSTRAK DAUN KERSEN (Muntingia calabura) DENGAN DOSIS BERBEDA TERHADAP LAMA INKUBASI, DAYA TETAS DAN KELULUSHIDUPAN LARVA IKAN LELE DUMBO (Clarias gariepinus)

ABSTRACT
 This study aims to determine the effect of the optimal dose of cherry leaf extract solution on incubation time, hatchability, and survival of larvae of catfish (Clarias gariepinus). The research used an experimental method using a Completely Randomized Design (CRD) with 5 treatments and 3 replications, namely: (P1) 2,0 gr/l, (P2) 2,5 gr/l, (P3) 3,0 gr/l , (P4) 3,5 gr/l and (P5) 4,0 gr/l. The test eggs used came from artificial spawning at the Fish Seed Center (BBI), Riau Islamic University. The container used is a jar with a capacity of 10 liters of 15 pieces. This research was conducted for 21 days on October 2019 at the Laboratory of Fish Seed Center (BBI), Faculty of Agriculture, Riau Islamic University, Pekanbaru. The results showed that the best adhesion was found on (P5) 4,0 gr/l of 98,89%. The incubation time and hatchability of the best treatment at (P3) 3,0 gr / l, the incubation time is 17 hours 27 minutes with a hatchability of 83,33%. Furthermore, the best treatment life was on (P2) 2,5 gr/l was 42,08%. The results of measurements of water quality parameters in this study had temperatures ranging from 290 C - 340 C, pH 6,0-6,5, ammonia between 0,28-0,97 and DO range between 3,14-3,81.
 Keywords: Dumbo catfish, Long incubation, Hair power, Graduation, Cherry leaves, Hatchability

Comparison of artificial spawning effectiveness of hCG, CPH and GnRHa in combination with dopamine inhibitors in a wild strain of ide Leuciscus idus (L.) in hatchery conditions

Optimization of artificial reproduction, by increasing the survival rate of embryos and hatching rate, is of major importance for reducing genetic diversity, especially in fish captured from their natural habitat that subsequently spawn in hatcheries. The artificial reproduction of ide, Leuciscus idus (L.) was conducted in controlled conditions. The spawning agents included: different doses of human chorionic gonadotropin (hCG) that was compared with common carp pituitary homogenate (CPH), Ovopel – a commercial agent for induction of spawning that contains mammalian gonadotropin releasing hormone analogue (mGnRHa) with dopamine antagonists (DA): metoclopramide (MET) and Ovaprim – a commercial agent containing salmon gonadotropin releasing hormone analogue (sGnRHa) and a dopamine antagonists (DA): domperidone (DOM). There were no ovulations in females from control groups. There were no differences between the ovulation rates (90 %) or embryo survival (> 92 %) and hatching rates (> 91 %) when there was administration of hCG doses between 500 and 1000 IU/kg. When there was comparison of different spawning agents, the ovulation rate was 100 % for all treated groups. There were the shortest and longest latency times to the time of ovulation after administration of CPH (26 h) and hCG (79 h), respectively. The greatest embryo survival (> 93 %) and hatching (> 91 %) rates occurred as a result of hCG administration with these values being slightly greater than when there was treatment with Ovaprim. The association between latency time and hatching rate indicated that when there was a slower final oocyte maturation (FOM) there were greater hatching rates.

Сравнительная оценка гормональных индукторов искусственного нереста самок африканского клариевого сома

Сравнительная оценка гормональных индукторов искусственного нереста самок африканского клариевого сома

Spermatozoa morphology and reproductive potential in F1 hybrids of common carp (Cyprinus carpio) and gibel carp (Carassius gibelio)

Sterility and semi-sterility often occur as a result of interspecific hybridization; however, the exact cause of sterility varies across the all animal kingdom; therefore, it is in the interest of scientists to examine every hybrid species separately. In the present study, the morphology of the spermatozoa of diploid F1 hybrids of Cyprinus carpio and Carassius gibelio was examined and compared with their parents. Hybrid spermatozoa showed great variability in head and flagellum lengths. These spermatozoa were diploid and triploid often with morphological abnormalities such as multiple flagella and nuclei. They were motile within two minutes after water activation which was almost two times longer than their parental species. We also analysed the reproductive output of F1 hybrids together with parental species in both parent positions via artificial spawning. Overall, the reproductive output of the hybrid × hybrid combination was the lowest; however, the hybrids were able to produce a small number of offspring documenting the viability of the F2 generation.

The effect of concrete tanks for the breeding technique of the sand sea cucumber (Holothuria scabra)

Sea cucumber are one of the Echinodermata type that have nutritional value in high protein content and as the sea of commodities with high economical value. The attempts to Obtain sea cucumber are Increasingly declining. Based on the review above, it is noticed that the cultivation of sea cucumber are needed to fulfill the needs of the market and restore the wild population. Sand sea cucumber breeding begins with the preparation of the broodstock rearing media, the availability preparation of the broodstock, water quality management, the broodstock feeding, the broodstock selection for high quality broodstock, conducting the artificial spawning using the method of temperature shock, egg incubation, hatching egg, and the larval rearing. The larvae were fed using the phytoplankton Chaetoceros sp. with a feeding frequency of once per day. The water quality parameters measured include temperature, DO, pH and salinity. The obstacles that were found on the sand sea cucumber breeding is the difficulty of getting the high quality of the broodstock, so the egg produced from spawning process are limited.

Evolution of artificial spawning sites for Atlantic salmon (Salmo salar) and sea trout (Salmo trutta): field studies and numerical modelling in Aurland, Norway

The presented study investigates the evolution of artificial gravel placements for Atlantic salmon and sea trout in Aurlandselva in Western Norway. Various monitoring methods have been applied including (i) quantifying the spatial extent and dynamics of spawning sites over the monitoring period, (ii) grain size distributions as well as (iii) applying numerical hydraulic and sediment transport modelling with the aim to test the predictability of such numerical tools. The spawning sites were not clogged by fine sediments, but were reshaped due to scouring and sediment transport. The scouring resulted in a volume loss of the gravel banks between 32 and 95% in the monitoring period of 5 years. The application of hydrodynamic-numerical modelling, however, showed that the modelling methods were not sufficient to predict erosion of the gravel or the site. The study showed that the areas are sensitive especially to local scale micro-topographical roughness elements. The complex three-dimensional hydraulic processes and the coarse substrate in the non-fluvial river environment makes it impracticable for multi-dimensional modelling to predict dynamics of gravel. A novel sediment criterion was introduced to estimate the near-bottom turbulence by relating the dm of introduced gravel compared to the d90 of the bed surface substrate composition.

Understanding the population structure and reproductive behavior of hatchery-produced yellowtail kingfish (Seriola lalandi)

The yellowtail kingfish (Seriola lalandi) is a marine endemic fish, and a key species in the national programme for the diversification of Chilean aquaculture. Since it has been recently developed from wild fish, the biology of this species under production is to a large extent unknown. For example, the structure of the different populations used to create the national breeding programme is not well characterised. Moreover, due to the fact that it is not possible to perform stripping of broodstock in yellowtail kingfish, the genetic contributions of individuals are affected by the reproductive behaviour of this species. To increase our knowledge of the biology of this species under aquaculture conditions, the objectives of this study were: (i) to identify the population structures of wild and commercial populations of yellowtail kingfish obtained from different fisheries off the Chilean coast, and compare these to those of Mexican and Australian specimens and (ii) to study the reproductive behaviour of commercial yellowtail kingfish broodstock through paternity testing, to estimate the genetic contributions of individuals throughout the artificial spawning season in captivity. We used a set of 12 highly informative microsatellite markers optimised for paternity testing. The analysis of the population structure showed at least two clusters of yellowtail kingfish, including a single metapopulation from Chile and Australia (possibly explained by the migratory behaviour of this species in the Pacific Ocean), and the other from Mexico (which is most likely composed of California yellowtail, S. dorsalis). Some degree of admixture, albeit small, was observed between the populations from Mexico and Australia. Paternity analysis showed that the average ratio (male/female) contributing in a spawning event was 2.6, confirming the spawning behaviour observed in other species in this genus. Additionally, we observed that males participated in matings regularly during the whole spawning season. Using the results of this research, we recommend modifying the current implementation of yellowtail kingfish breeding programmes to reduce the effects of random genetic drift. This can be achieved by managing the genetic contributions of broodstock in a two-step breeding programme. This study provides useful genetic information for the long-term development and management of the Chilean yellowtail kingfish industry, which involves a species of high importance for the diversification of Chilean aquaculture.

Effect of Activated Milt Residence Time on Landlocked Fall Chinook Salmon Egg Survival

During artificial spawning of salmonids, activated sperm is allowed to remain in contact with eggs for variable durations. This study examined multiple residence times (20, 40, 60, 90, or 120 seconds) for activated sperm on landlocked fall Chinook salmon (Oncorhynchus tshawytscha) eggs during spawning. There was no significant difference in egg survival to the eyed-stage of development or to hatch among any of the treatments, with a mean (SE) percent survival to the eyed stage of 63.9 (5.8). These results indicate that only relatively short residence times of activated milt on eggs during landlocked fall Chinook salmon spawning are needed to ensure egg survival, resulting in potentially substantial reductions in production-level spawning times and associated labor costs.

Landlocked Fall Chinook Salmon Egg Storage for Delayed Fertilization

Delayed fertilization of salmonid eggs can be a useful option to enhance the efficiency of artificial spawning operations. This experiment examined the fertility of landlocked fall Chinook salmon (Oncorhynchus tshawytscha) eggs stored for various times after removal from female broodstock. Fertilization occurred either immediately after spawning or the eggs were stored with oxygen at 11°C and fertilized at 4, 6, 8, 12, or 20 hours post-spawn. Survival to the eyed stage of egg development was significantly greater in the eggs fertilized immediately or after four, six, or eight hours of storage compared to those eggs stored for 12 or 20 hours prior to fertilization (P = 0.024). Survival to hatch was also significantly different (P = 0.018) and followed the same pattern. This study is the first to document the successful fertilization of landlocked fall Chinook salmon eggs after eight hours of storage.

Features of puberty in female African Clary catfish in high-tech industrial aquaculture

There is a growing interest in African Clary catfish as a perspective object of industrial fishery in the Russian aquaculture in the last decade. This interest is due to the high growth rate of Clary catfish, its delicious meat and valuable caviar. This species has multiport spawning, so it is possible to get caviar from catfish several times a year. However, in high-tech industrial system of fish breeding, biology of fishes is modified, so that the African Clary catfish loses the ability to reproduce and produce full roe. For reproduction and production of full roe in industrial aquaculture, artificial spawning technologies are used with the use of hormonal drugs that induce the maturation of reproductive cells. The study is devoted to the dynamics of puberty in female African Clary catfish to identify the starting age of its possible use in the reproductive process and in the production of caviar. The results showed that at the age of 8 months, the reproductive system of females reached maturity, females were able to reproduce posterity. However, its reproductive performance in this period, in particular caviar productivity, was very low. The age of 12 months can be considered the starting age for caviar production. Caviar productivity continued to grow, reaching a maximum at the age of 18-24 months, and depended on the weight of females. Working fertility of females and gonadosomatic index at the age of 12-24 months were characterized by increasing dynamics. The size and weight of oocytes during this period reached definitive sizes.

Biochemical Changes in Blood of African Catfish (Clarias Gariepinus Burchell, 1822) during Artificial Spawning Using Different Doses of Human Chorionic Gonadotropin (HCG) Hormone

Biochemical Changes in Blood of African Catfish (Clarias Gariepinus Burchell, 1822) during Artificial Spawning Using Different Doses of Human Chorionic Gonadotropin (HCG) Hormone

Performance of Pregnant Mare Serum Gonadotropin and Vitamin Mix in Inducing Striped Catfish Pangasianodon hypophthalmus Rematuration

The research aimed to assess the performance of Pregnant Mare Serum Gonadotropin (PMSG) and Human Chorionic Gonadotropin (HCG) hormone injection combined with vitamin mix to induce the rematuration of Striped catfish Pangasianodon hypophthalmus broodstock. Three PMSG and HCG treatments of 5 and 2,5 IU; 10 and 5 IU;also 20 and 10 IU/kg of broodstock body weight dosage combined with vitamin mix addition to fish feed and one control was used with four replications. The broodstock was reared for four weeks and weekly sampling for GR and SGR as well as hormone injection were performed. For the following two weeks, the broodstock was observed for maturation. Artificial spawning was conducted for broodstock reaching gonadal maturity. Statistic analysis of observed variables showed insignificant differences among the three treatments in rematuration parameters. The rematuration rate resulted in a 100% pregnancy. Broodstock treated with 10 IU PMSG and 5 IU HCG/kg of spawner body weight was able to reach maturity and spawned with the larval survival rate on the fourth day at 84,81%, thus it can be concluded that 10 IU PMSG and 5 IU HCG/kg of body weight as the best dosage.

Distinctive reproductive tactics between sympatric specimens of Astyanax aff. fasciatus in the wild and in captivity

Astyanax fasciatus is a group of neotropical fish with two different diploid chromosome numbers, and in the wild, these individuals are found in sympatry. The annual reproductive cycles of adult females of species with different numbers of chromosomes (G1: 46 chromosomes, low responsiveness to induced spawning; G2: 48 chromosomes, responsive to induced spawning) were investigated in the wild and in captivity. Plasma estradiol (E2) levels, relative fecundity (RF), oocyte diameter, gonadosomatic index, and ovarian morpho-histology were evaluated to identify the ovarian maturation stage. The G1 females in both environments began the vitellogenic phase during winter, concurrent with increased plasma E2 levels. In wild G1 females, large numbers of vitellogenic oocytes were observed during spring and summer, when plasma E2 levels remained high. In contrast, captive G1 females showed higher E2 levels during the winter. They also retained significantly higher RF and vitellogenic oocyte numbers than wild females, but showed no spawning and slow yolk reabsorption. Wild G2 females began the vitellogenic phase in autumn and had progressively increasing E2 levels that peaked in the spring, with spawning occurring during the summer. In captive G2 females, the E2 levels and RF remained high throughout the year. These data suggest that A. aff. fasciatus with different numbers of chromosomes differ in their reproductive performance in the wild and show altered sensitivity to environmental cues in captivity. Our results indicate that G1 females likely respond best to artificial spawning just after winter, whereas G2 females should respond year-round.

A novel attempt at artificial spawning of captive bonefish ( Albula spp.)

Aquaculture ResearchVolume 50, Issue 9 p. 2718-2723 SHORT COMMUNICATION A novel attempt at artificial spawning of captive bonefish (Albula spp.) Sahar Mejri, Corresponding Author Sahar Mejri smejri@fau.edu orcid.org/0000-0002-3346-5934 Harbor Branch Oceanographic Institute, Florida Atlantic University, Boca Raton, Florida Correspondence Sahar Mejri, Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 US1-N, Fort Pierce 34946, FL. Email: smejri@fau.eduSearch for more papers by this authorWilliam R. Halstead, William R. Halstead Harbor Branch Oceanographic Institute, Florida Atlantic University, Boca Raton, FloridaSearch for more papers by this authorCameron A. Luck, Cameron A. Luck Harbor Branch Oceanographic Institute, Florida Atlantic University, Boca Raton, FloridaSearch for more papers by this authorChristopher Robinson, Christopher Robinson Harbor Branch Oceanographic Institute, Florida Atlantic University, Boca Raton, FloridaSearch for more papers by this authorTravis E. Van Leeuwen, Travis E. Van Leeuwen Cape Eleuthera Institute, Rock Sound, Eleuthera, The Bahamas Fisheries and Oceans Canada, St. John’s, Newfoundland, CanadaSearch for more papers by this authorAaron J. Adams, Aaron J. Adams Harbor Branch Oceanographic Institute, Florida Atlantic University, Boca Raton, Florida Bonefish and Tarpon Trust, Coral Gables, FloridaSearch for more papers by this authorJon Shenker, Jon Shenker Florida Institute of Technology, Melbourne, FloridaSearch for more papers by this authorMatthew J. Ajemian, Matthew J. Ajemian Harbor Branch Oceanographic Institute, Florida Atlantic University, Boca Raton, FloridaSearch for more papers by this authorPaul S. Wills, Paul S. Wills Harbor Branch Oceanographic Institute, Florida Atlantic University, Boca Raton, FloridaSearch for more papers by this author Sahar Mejri, Corresponding Author Sahar Mejri smejri@fau.edu orcid.org/0000-0002-3346-5934 Harbor Branch Oceanographic Institute, Florida Atlantic University, Boca Raton, Florida Correspondence Sahar Mejri, Harbor Branch Oceanographic Institute, Florida Atlantic University, 5600 US1-N, Fort Pierce 34946, FL. Email: smejri@fau.eduSearch for more papers by this authorWilliam R. Halstead, William R. Halstead Harbor Branch Oceanographic Institute, Florida Atlantic University, Boca Raton, FloridaSearch for more papers by this authorCameron A. Luck, Cameron A. Luck Harbor Branch Oceanographic Institute, Florida Atlantic University, Boca Raton, FloridaSearch for more papers by this authorChristopher Robinson, Christopher Robinson Harbor Branch Oceanographic Institute, Florida Atlantic University, Boca Raton, FloridaSearch for more papers by this authorTravis E. Van Leeuwen, Travis E. Van Leeuwen Cape Eleuthera Institute, Rock Sound, Eleuthera, The Bahamas Fisheries and Oceans Canada, St. John’s, Newfoundland, CanadaSearch for more papers by this authorAaron J. Adams, Aaron J. Adams Harbor Branch Oceanographic Institute, Florida Atlantic University, Boca Raton, Florida Bonefish and Tarpon Trust, Coral Gables, FloridaSearch for more papers by this authorJon Shenker, Jon Shenker Florida Institute of Technology, Melbourne, FloridaSearch for more papers by this authorMatthew J. Ajemian, Matthew J. Ajemian Harbor Branch Oceanographic Institute, Florida Atlantic University, Boca Raton, FloridaSearch for more papers by this authorPaul S. Wills, Paul S. Wills Harbor Branch Oceanographic Institute, Florida Atlantic University, Boca Raton, FloridaSearch for more papers by this author First published: 12 June 2019 https://doi.org/10.1111/are.14207Citations: 5 William R. Halstead and Cameron Luck contributed equally to the manuscript. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume50, Issue9September 2019Pages 2718-2723 RelatedInformation

Genetic variability of an orange-shell line of the Pacific oyster Crassostrea gigas during artificial selection inferred from microsatellites and mitochondrial COI sequences

Rare breeds represent a valuable resource for current or future market demands, but their low census compromises the genetic variability and future utilization of these breeds. Whether genetic variability of rare breeds with low initial genetic variation can be maintained during an intense mass selection becomes the key to applying mass selection to the genetic improvement of these breeds. The genetic variability among three generations of successive mass selection of the orange-shell line of Crassostrea gigas (MS1–MS3) were evaluated by both 20 nuclear microsatellite loci and mitochondrial cytochrome oxidase I sequences (mtCOI) compared to four wild populations. In this study, the orange-shell line exhibited very low genetic variability. Only one mtCOI haplotype was detected in all individuals of MS1–MS3. Significant reductions in average number of alleles (Na: 69.55–76.92%), allelic richness (Ar: 68.17–74.91%) and expected heterozygosity (He: 34.21–39.24%) as well as increased mean pairwise genetic relatedness (R: 6.87–25.79 times) were observed in MS1–MS3 when compared to wild populations. However, the genetic variability of orange-shell line with very low initial variation successfully maintained during three generations of mass selection. No significant difference in Na (3.60–4.40), Ar (3.51–4.08) and He (0.48–0.50) occurred among MS1–MS3. Pedigree reconstructions (no full-sib group from MS1–MS3 was larger than 16% of the whole group) revealed artificial spawning used in this study has a better control over contribution of gametes than traditional mass spawning. In addition, effective population size of MS1–MS3 calculated by linkage disequilibrium methods increased from 29.3 to 67.0 indicating the linkage disequilibrium decays over time. This study provides important insights in the genetic consequences of a rare variant line of C. gigas with very low genetic variation over generations of mass selection. This will provide a reference for carrying out genetic improvement programs on rare breeds where small populations are inevitable.

The influence of difference temperature against the rate of embryonic development and larval abnormality of Cantik Grouper (Epinephelus sp.)

Cantikgrouper is the hybridization results grouper or cross-breeding between Epinephelus fuscoguttatus as a female and Epinephelus microdon as a male. The main barriers faced in the development of this commodity is still low levels of spawning up to seeding grouper. Based on the background, this study aimed to investigate optimum temperature observations against the rate of embryonic development Epinephelus sp.larvae. This study used the results of artificial spawning eggs.The fertilized eggs were incubated on six pieces of the container temperature treatment;each treatment there was repeated three times.The incubation temperature was kept on (A) 21-22°C; (B) 23-24°C; (C) 25-26°C; (D) 27-28°C; (E) 29-30°C; (F) 31-32°C. Results showed that eggswere incubated at a temperature of 21-22 ℃ embryonic development to a halt in the blastula, and temperature 23-24°C stalled on phasemyomere embryos. The low-temperature incubation period lasts a long time. Temperature 25-26°C needed 18 hours 6 minutes by 8.33% abnormality rate. Temperature 27-28°C needed 16 hours to hatch witha degree of abnormality of 7.6%. Temperature 29-30°C needed 15 hours 1 minute for the hatch tothe degree of abnormality of 5.33%. The 31-32°C temperature needed 14 hours 6 minutes to hatch witha degree of abnormality of 17.3%. The limits of tolerance for the incubation of the eggs ofcantik grouper (Epinephelusspp.) were 26-32°C.The best temperature of each treatment were obtained at a temperature of 29-30°C. Based on our results, it concluded that the changing temperature affected how long eggs could hatch.

Penerapan teknik pembenihan dan budidaya ikan baung di Desa Batu Belah, Kecamatan Kampar, Riau

Tujuan dari kegiatan program ini adalah untuk memberikan ilmu dan teknologi tentang teknik pembenihan dan budidaya ikan baung di Desa Batu Belah, Kecamatan Kampar khususnya pada Kelompok Pembenihan Rakyat (KPR) Lele Sejahtera dan Kelompok Budidaya Ikan (Pokdakan) Mina Karya. Metode yang digunakan dalam kegiatan PKM ini adalah metode ceramah, diskusi dan demonstrasi langsung ke lapangan. Hasil evaluasi perubahan pengetahuan dari 10 orang peserta anggota Kelompok Pembenihan Rakyat (KPR) Lele Sejahtera diperoleh 7 orang (70,00%) telah dapat menyerap materi yang diberikan dengan predikat sangat baik selebihnya predikat baik dan cukup. Selanjutnya dari 11 orang peserta anggota Kelompok Budidaya Ikan (Pokdakan) Mina Karya diperoleh 8 orang (72,23%) telah dapat menyerap materi yang diberikan dengan predikat sangat baik, selebihnya predikat baik dan cukup. Hasil evaluasi keterampilan menunjukkan bahwa peserta kegiatan telah dapat mempraktekkan materi tentang pembenihan ikan baung melalui pemijahan buatan dan teknologi budidaya budidaya ikan baung. Selanjutnya dari hasil evaluasi dampak menunjukkan dampak kegiatan ini telah dirasakan menfaatnya oleh anggota kedua kelompok tani yang ada, sehingga akan dapat meningkatkan pendapatan anggota kedua kelompok tani tersebut, sekaligus dapat meningkatkan kesejahteraannya.

Growth hormone on ovarian morphology of lambaris (Astyanax bimaculatus) after induced spawning

ABSTRACT: Lambari, Astyanax bimaculatus, is an oviparous, multiple-spawning fish that is reproductively active throughout the year, which makes it promising for cultivation and research. This research histologically evaluates the ovaries of lambari that have undergone artificial spawning induced with pituitary extract (control group), and the effect of growth hormone at a dose of 2 mg/g body weight (treatment group) on the subsequent process of ovarian recovery. Ovaries of fish in both the control and treatments groups were collected at 120 hours after spawning and analyzed using optical microscopy to characterize the average quantities of: follicles in different stages of development, post-ovulatory follicles, follicular atresia and granulocytes. Quantity and morphology of early and advanced primary follicles did not differ between the treatment and control groups; an important and necessary factor for ovarian recovery for subsequent spawning. There was a greater amount of granulocytes in initial atresia in the group treated with growth hormone. These results demonstrated that the administration of growth hormone may potentiate the process of ovarian recovery after induced spawning.

An Assessment of an Unsuccessful Restoration Project for Lake Sturgeon Using Three‐Dimensional Numerical Modelling

AbstractDespite a widespread acknowledgment that river restoration projects sometimes fail due to a poor understanding of geomorphology and hydrology, there are relatively few published case studies reporting failures, particularly for nonsalmonid species such as Lake Sturgeon Acipencer fulvescens. We used a three‐dimensional hydrodynamic model to retroactively assess a restoration project in the 80‐m‐wide Ouareau River, Quebec which did not meet its objective of providing additional spawning habitat for Lake Sturgeon. Virtual modifications of the bathymetry allowed for the flow field to be simulated with and without instream structures (boulder weirs) constructed in 2007 for four discharges representing flow conditions during spawning. Simulated velocities and flow depths were used to determine the suitability of the site and to assess the impact of the instream structures. Results revealed that instream structures did not meet the expectation of raising water levels and had no significant impact on river velocity. Furthermore, there was sufficient good quality habitat within the study area before restoration, and artificial spawning sites were placed in locations with nonoptimal velocities for spawning Lake Sturgeon. A comparison with a successful Lake Sturgeon restoration project in the St. Clair–Detroit River system revealed marked differences in restoration strategies, which likely explain the different outcomes of these two projects. These results point to the need for (1) adaptive management protocols that include an iterative decision‐making process to allow for adjustments in hypotheses and strategies to improve the management process, (2) multidisciplinary input, including hydrogeomorphology, and (3) a more systematic use of two‐dimensional or three‐dimensional numerical models prior to the implementation of instream structures in river restoration projects.