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The goal of this study was to test a commercial scale larval rearing tank with a self-cleaning mechanism to improve larval rearing success for marine fish. Four trials were conducted to compare the performance of a self-cleaning tank (SCT) to a control (CON) larval rearing tank. Two trials were conducted using California yellowtail (CYT; Seriola dorsalis) and two were conducted using white seabass (WSB; Atractoscion nobilis). Metrics collected for each trial included, larval growth, survival, bacterial colony counts (Vibrio spp.), total suspended solids concentrations, and labor (time spent siphoning the tanks). There were no differences in growth between tanks for either species. CYT survival in Trial 1 resulted in better survival in the CON tank (56.8%) than in the SCT (32.8%). WSB survival in both Trial 1 and 2 was higher in the SCT than in the CON tank (35.5% versus 26.9% and 15.8% versus 10.1%, respectively). We suspected that the cleaning arm was likely causing early mortality in both species (between 0 and 16 days post hatch; dph), therefore, Trial 2 involved only cycling the arm twice per day for one hour until the larvae were 16 dph. This modification yielded improved survival in the SCT (60.5%) than CON tank (47.1) but only for the CYT. Total suspended solids were higher in the CON tank for both species (up to 8.0 mg/L). Bacteriology results showed higher CFU counts for CYT in the CON tanks from 8 to 24 dph, and at 24 dph counts were higher in SCT. CFU counts were higher for WSB in the CON tank at 9 and 13 dph but otherwise there were no differences over time. Perhaps most notable was that the SCT tanks yielded a fourfold reduction in labor when compared to CON tanks due to more efficient siphoning.

Abstract Patella candei d'Orbigny, 1840 is a valuable resource from the European Macaronesia. Limpet aquaculture is a recent research field that could contribute to reducing anthropogenic impact and developing appropriate restocking technologies. This study presents the results of 14 assays performed under laboratory culture conditions aimed at: (1) improving the larval production methodologies for limpets through the optimization of the artificial maturation of the oocytes and the sperm density required for fertilization and incubation, (2) validating a larviculture protocol for P. candei, and (3) evaluating rearing density effect on larvae performance until the pediveliger stage. Results obtained in the present study indicate that NH4OH is more efficient than KOH and NaOH to enhance the artificial maturation of the oocytes. The optimal combination was NH4OH at pH 9.0 for a duration of 20–30 min. The optimal sperm density was approximately 105 sperm cells mL−1 as in other limpet species. The larviculture method described hereby demonstrated to be efficient to obtain viable pediveligers, that is, the larval survival was high, and the artificial maturation did not influence negatively the posterior larval development. The rearing density, within a range from 2.5 to 30 larvae mL−1, showed minimal influence on survival and development.

T. molitor larvae were fed with wheat bran (W) and supplemented (1:1) with cucumber (C + W) or tomato (T + W) agricultural wastes, from conventional or ecological farming, for 6 weeks. Weekly and fortnightly measurements of larvae weight/tray and length were taken, respectively. At the end of the study, the fatty acid composition of the larvae was analyzed using GC-MS. On day 43, the weight of larvae supplemented with wastes almost doubled that reached by the control larvae (647–720 vs. 370 g/tray), which were 15% smaller. Supplementation decreased the larval fat content and increased the polyunsaturated fatty acids between 22–37%, with linoleic acid being the most abundant. [ABSTRACT FROM AUTHOR]

Patella candei d'Orbigny, 1840 is a valuable resource from the European Macaronesia. Limpet aquaculture is a recent research field that could contribute to reducing anthropogenic impact and developing appropriate restocking technologies. This study presents the results of 14 assays performed under laboratory culture conditions aimed at: (1) improving the larval production methodologies for limpets through the optimization of the artificial maturation of the oocytes and the sperm density required for fertilization and incubation, (2) validating a larviculture protocol for P. candei, and (3) evaluating rearing density effect on larvae performance until the pediveliger stage. Results obtained in the present study indicate that NH4OH is more efficient than KOH and NaOH to enhance the artificial maturation of the oocytes. The optimal combination was NH4OH at pH 9.0 for a duration of 20–30 min. The optimal sperm density was approximately 105 sperm cells mL−1 as in other limpet species. The larviculture method described hereby demonstrated to be efficient to obtain viable pediveligers, that is, the larval survival was high, and the artificial maturation did not influence negatively the posterior larval development. The rearing density, within a range from 2.5 to 30 larvae mL−1, showed minimal influence on survival and development. [ABSTRACT FROM AUTHOR]

T. molitor larvae were fed with wheat bran (W) and supplemented (1:1) with cucumber (C + W) or tomato (T + W) agricultural wastes, from conventional or ecological farming, for 6 weeks. Weekly and fortnightly measurements of larvae weight/tray and length were taken, respectively. At the end of the study, the fatty acid composition of the larvae was analyzed using GC-MS. On day 43, the weight of larvae supplemented with wastes almost doubled that reached by the control larvae (647–720 vs. 370 g/tray), which were 15% smaller. Supplementation decreased the larval fat content and increased the polyunsaturated fatty acids between 22–37%, with linoleic acid being the most abundant.

The production of cultured limpets is a recent research field contributing to aquaculture diversification, focusing on low trophic species while reducing the carbon footprint. Limpets are gastropods that colonize rocky substrates and are mostly present on tidal and subtidal shores. This animal group is in high commercial demand and is endangered in several regions. The aquaculture production of limpets has been traditionally challenging. The most successful reproduction method has been gonadal dissection, as artificial spawning induction has shown limited success to date. Moreover, methods for larval culture, settlement, and juvenile growth have been poorly developed and remain largely unknown. In recent years, advances in this field have led to the optimization of methods to enhance larval production, larval culture, settlement induction of competent larvae, and management of post-larvae and juveniles. The present manuscript reviews these advances, obtained within the framework of AQUAINVERT project, focusing on broodstock management, gametes release, larval production, larviculture, settlement, and grow-out of post-larvae, and providing an update on the actual state of the art in limpets’ aquaculture.

Empirical evidence for increases in the reproductive potential (egg output per unit area) of coral reef fish in no‐take marine reserves (NTMRs) is sparse. Here, we inferred the development of reproductive potential in two species of protogynous reef fishes, Chlorurus bleekeri (Labridae: Scarinae) and Cephalopholis argus (Epinephelidae), inside and outside of Philippine NTMRs. We estimated key reproductive parameters and applied these to species‐specific density and length data from 17 NTMRs (durations of protection 0–11 years) and paired fished sites (controls) in a space‐for‐time substitution approach. For C. argus, we also used density and length data collected almost annually over 29 years from a NTMR and an adjacent control at Apo Island. The results suggest that C. bleekeri can develop 6.0 times greater reproductive potential in NTMRs than controls after 11 years of protection, equivalent to approximately 582,000 more eggs produced 500 m−2 inside NTMRs. Enhancement of reproductive potential in C. argus was not evident after 11 years in the space‐for‐time substitution. At Apo Island NTMR, reproductive potential of C. argus increased approximately 6‐fold over 29 years but NTMR/control ratios in reproductive potential decreased through time (from 3.2 to 2.4), probably due to spillover of C. argus from the NTMR to the control. C. argus was estimated to produce approximately 113,000 more eggs 500 m−2 inside Apo Island NTMR at the 29th year of protection. Ratios of reproductive potential between NTMR and controls in C. bleekeri and C. argus were often greater than corresponding ratios in density or biomass. The study underscores the importance of species‐specific reproductive life history traits that drive variation in the development of larval fish subsidies that originate from NTMRs. [ABSTRACT FROM AUTHOR]

Limpet species are subjected to pressures of high exploitation. In the Madeira Archipelago (Portugal), the limpes are an economic and traditional fishing resource whose exploitation is regulated, to reduce the impact over the native populations. The effectiveness of the NaOH-alkalinized seawater baths to enhance the artificial maturation of Patella candei (D′orbigny, 1840) oocytes and fertilisation success in laboratory has been studied. First, the optimal combinations of pH and activation time to obtain the active oocytes were tested. Then, the viability of those oocytes was studied in a three factorial assay (pH x activation time x fertilisation time). Finally, the results obtained in the previous assays were cross tested to find a relationship between both. The viability of the oocytes over time were tested for methodology improvement. Results showed that the optimal conditions for the production of larvae was a pH of 9.5, activation time between 2 and 3 h and fertilisation time of 24:00 h, obtained a ratio of development between 0.65 and 0.75. The refrigeration could help to maintain the oocyte viability over time, but further research is required. This study establishes a foundational step towards the study the larval biology of Patella candei in laboratory, which is required to understand the ecological requirements for the early life stages of this species and promote aquaculture production.

The study was designed to investigate the rate of larval (maggot) production from different culture enclosures, as well as to compare the cost effectiveness and utilization of the maggot in the diet of African mud catfish, Clarias gariepinus. Musca domestica larvae were cultured from poultry dung for five week, where upon they were utilized as a replacement for fish meal in the diet of fingerlings of African mud catfish. The maggots were cultured in four different enclosures: aluminium mobile maggotry, aluminium, plastic and wooden boxes. The harvested maggots were processed by oven drying and powdered as maggot meal. The maggot meal was used to substitute fish meal in eight diets with different inclusion levels of 0% (control), 20%, 30%, 40%, 50%, 60%, 70% and 80%. The formulated diets were fed to C. gariepinus fingerlings in triplicates for 10 weeks. The growth, nutrient utilization and survival of fish were monitored during the experimental period. The cost effectiveness of different culture enclosure was studied. Results indicate that aluminium box was the best option, giving the highest weight of maggot production, and was the most cost effective of all the culture enclosures studied. Significant differences (p < 0.05) were recorded in weight gain of fish between the control and the maggot meal-based diets, while the highest weight gain was observed in fish fed 70% maggot meal-based diet. Specific and relative growth rates were found to be high in fish fed 60% maggot meal diet, while they were lowest in fish fed 20% maggot meal diet and the control diet. The best protein intake was recorded in fish fed the 70% maggot meal-based diet and lowest in fish fed the control diet. Survival of fish was generally high (78.3%-93.30%) and was significantly (p < 0.05) different between the fish fed as the control and the maggot meal-based diets. The study confirms that maggots of Musca domestica are suitable as partial replacement of fishmeal at 60-70% inclusion level for optimal growth performance and nutrient utilization in Clarias gariepinus fingerlings.

Climate change has led to major shifts in the timing of biological events, with many studies demonstrating earlier phenology in response to warming. However, few of these studies have investigated the effects of climate change on the phenology of larvae in marine species. Phenological shifts can result in mismatches between consumers and prey and hence affect growth and survival of individuals, and ultimately population demography. We investigated the temporal changes in phenology and abundance of the larvae of dominant brachyuran crabs in the southern Gulf of St. Lawrence (eastern Canada) based on plankton collections spanning 1982–2012. The Gulf of St. Lawrence has warmed since the early 1990s, and our analyses revealed that larvae of snow crab (Chionoecetes opilio) and toad crabs (Hyas spp.) exhibited a significant trend towards earlier phenology over the 30‐year study period. This shift in phenology appeared to be a consequence of the effect of climate warming on both the timing of hatching and larval development rate. Larval abundance responded differently by crab taxon to climate warming, likely due to differences in thermal tolerance. The warming trend was unfavourable to snow crab, which is the most cold‐adapted and stenothermic of the taxa examined in this study. The abundance of snow crab larvae was lower when sea ice retreat occurred earlier than day 110 of the year and sea surface temperature was higher than 8.5°C. On the other hand, larval abundance of rock crab (Cancer irroratus), which prefers higher temperatures, was positively related to surface temperature. [ABSTRACT FROM AUTHOR]

The processes influencing recruitment in sea urchins are poorly understood. To examine the depensatory density-dependent reproduction of broadcast spawning invertebrates, I created a simulation model of fertilization dynamics. The model described decreased fertilization success as density decreased, and increased fertilization as the aggregation of adult spawners increased. Highest fertilization success resulted from simulations with wide gamete dispersal distributions with an extended tail, representing low flow conditions. Surprisingly, the model did not predict a deterministic Allee effect or minimum threshold density of spawners for successful fertilization. but instead produced a gradual non-linear decline in larval production at low densities. A stochastic Allee effect was observed, as the variability in larval production increased substantially at low density.To estimate current larval production of the red sea urchin Strongylocentrotus franciscanus, I applied this fertilization model to observed spatial distributions. Adult sea urchins were censused at eleven sites to determine density and local spatial distribution. Reserve sites generally had higher densities than fished sites. All sites were significantly aggregated, and aggregation increased as density decreased. Fertilization success was strongly influenced by both density and aggregation. Estimated current larval production was approximately one-third of estimated pre-fishery larval production, with 75% of the decline attributable to declines in mean density, and the fertilization Allee effect responsible for the remainder of the decline.To evaluate density-independent influences on recruitment, I examined settlement patterns of juvenile sea urchins and crabs in northern California Prior research had determined an intra-annual pattern of settlement during local wind relaxation events. This pattern was present during the 1998 El Niño, resulting in high settlement of cancrid crabs and sea urchins. The 1999 La Niña lacked the typical upwelling/relaxation pattern, and low settlement was observed.These results illustrate several aspects of population dynamics that should be considered in fisheries management and reserve design. Decreased adult density can have long-lasting effects if reproductive potential is affected. Local oceanographic transport of planktonic larvae can result in spatial and temporal variability in juvenile settlement. Researchers will need to consider both reproductive potential and settlement variability when designing reserve networks.

BACKGROUND Hypothenemus hampei Ferrari (Coleoptera: Curculionidae) is the main pest of coffee due to the damage caused to coffee berries. Effective management methods and prevention of insecticide resistance are urgently needed against this insect. Bioassays were conducted to assess the effects of the diamide insecticide cyantraniliprole on H. hampei. Cyantraniliprole is the most recent compound registered against this species after the phasing out of endosulfan, the main insecticide historically used against the coffee borer for the past 30 years. Toxicity, survival, progeny production, respiration rate, and behavioral responses to cyantraniliprole were evaluated. RESULTS: Cyantraniliprole was toxic to adult H. hampei (LC50 = 0.67 mg mL−1 and LC90 = 1.71 mg mL−1). Adult survival was 95% without exposure to cyantraniliprole, decreasing to 52% in insects exposed to LC50 cyantraniliprole and 27% in insects treated with LC90 cyantraniliprole. Furthermore, H. hampei showed reduced mobility on insecticide‐treated surfaces. The insecticide also led to a decrease in the respiration rate of H. hampei for up to 3 h after exposure, altering behavioral responses and locomotor activity. CONCLUSION: Cyantraniliprole exhibits lethal and sublethal effects on H. hampei and can be used in rotation in integrated pest management programs for control of this species in coffee cultivation systems. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Abstract Hypothenemus hampei Ferrari (Coleoptera: Curculionidae) is the main pest of coffee crops, and effective methods for pest management are needed urgently. Bioassays were conducted to assess the effects of the insecticide chlorantraniliprole on H. hampei adults. Toxicity, survivorship, larval production, respiration rate, and behavioral responses to six concentrations of chlorantraniliprole were evaluated. Chlorantraniliprole was toxic to H. hampei (LD 50 = 0.49 mg mL−1 and LD 90 = 1.21 mg mL−1). Survivorship was 98% in adults not exposed to chlorantraniliprole, decreasing to 52% in insects exposed to LD 50 and 2% in insects treated with LD 90. H. hampei showed reduced mobility on insecticide-treated surfaces. The insecticide promoted a decrease in the respiration rate of H. hampei for up to 3 h after exposure, altering behavioral responses and locomotor activity. Chlorantraniliprole was shown to have lethal and sublethal effects on H. hampei and, thus, can be used rotationally in integrated pest management programs to control of this pest in coffee crops and retard of insect resistance. Highlights • The control of coffee berry borer is carried out through conventional insecticides as endosulfan. • The insecticidal effects of the anthranilic diamide chlorantraniliprole were tested on H. hampei. • Chlorantraniliprole was toxic and reduced the survivorship of H. hampei at different lethal and sublethal concentrations. • Chlorantraniliprole exhibited significant activity to effectively disrupt the larval stage, altering the locomotor activity and reducing the respiration rate. • Lethal and sublethal effects of chlorantraniliprole in H. hampei can be an alternative control to endosulfan. [ABSTRACT FROM AUTHOR]

Abstract Antibiotics have been used massively for aquatic organism production. However, their use should be limited given the problems of increased antibiotic resistance, and new alternatives should be attempted, such as the use of plants extracts with antibacterial properties. The effect of the essential oil of oregano (Origanum vulgare) compared with three antibiotics (enrofloxacin, florfenicol, and oxytetracycline) on embryogenesis and early larval stages were evaluated to obtain mixotrophic larvae of the scallop Nodipecten subnudosus. Incubation densities of 20 and 100 fertilized oocytes mL−1 were used. The highest yield of normal larvae (calcified D-larvae) occurred at high densities in an order of 300% (36–45 D-larvae mL−1), with the highest values being obtained when the fertilized oocytes were treated with the oregano essential oil and with the antibiotic florfenicol, 44.8 ± 5.16 and 40.9 ± 12.06 D-larvae mL−1, respectively. Nevertheless, the use of florfenicol produced larvae with shorter anteroposterior length, which strengthens the advantage of using oregano essential oil over the antibiotics for spat production of N. subnudosus. Highlights • The potential of the oregano oil was examined in the production of scallop Nodipecten subnodosus larvae. • LD 50 of N. subnodosus embryos allowed to record the tolerance of up to 5 ppm of oregano oil. • The embryos of N. subnodosus at high densities (100 embryos mL-1) causes survival of mixotrophic larvae greater than 50%. • To produce mixotrophic larvae of the scallop N. subnodosus , the use of oregano oil provides advantages over antibiotics. [ABSTRACT FROM AUTHOR]

The study was designed to investigate the rate of larval (maggot) production from different culture enclosures, as well as to compare the cost effectiveness and utilization of the maggot in the diet of African mud catfish, Clarias gariepinus. Musca domestica larvae were cultured from poultry dung for five week, where upon they were utilized as a replacement for fish meal in the diet of fingerlings of African mud catfish. The maggots were cultured in four different enclosures: aluminium mobile maggotry, aluminium, plastic and wooden boxes. The harvested maggots were processed by oven drying and powdered as maggot meal. The maggot meal was used to substitute fish meal in eight diets with different inclusion levels of 0% (control), 20%, 30%, 40%, 50%, 60%, 70% and 80%. The formulated diets were fed to C. gariepinus fingerlings in triplicates for 10 weeks. The growth, nutrient utilization and survival of fish were monitored during the experimental period. The cost effectiveness of different culture enclosure was studied. Results indicate that aluminium box was the best option, giving the highest weight of maggot production, and was the most cost effective of all the culture enclosures studied. Significant differences (p < 0.05) were recorded in weight gain of fish between the control and the maggot meal-based diets, while the highest weight gain was observed in fish fed 70% maggot meal-based diet. Specific and relative growth rates were found to be high in fish fed 60% maggot meal diet, while they were lowest in fish fed 20% maggot meal diet and the control diet. The best protein intake was recorded in fish fed the 70% maggot meal-based diet and lowest in fish fed the control diet. Survival of fish was generally high (78.3%-93.30%) and was significantly (p < 0.05) different between the fish fed as the control and the maggot meal-based diets. The study confirms that maggots of Musca domestica are suitable as partial replacement of fishmeal at 60-70% inclusion level for optimal growth performance and nutrient utilization in Clarias gariepinus fingerlings. [ABSTRACT FROM AUTHOR]

Keystone reef-building corals in the Caribbean are predominantly self-incompatible broadcast spawners and a majority are threatened due to both acute adult mortality and poor recruitment. As population densities decline, concerns about fertilization limitation and effective population size in these species increase and would be further exacerbated by either high clonality or gametic incompatibility of parental genotypes. This study begins to address these concerns for two Caribbean broadcasting species by characterizing clonal structure and quantifying experimental pairwise fertilization success. Orbicella faveolata showed surprisingly high and contrasting levels of clonality between two sampled sites; Acropora palmata was previously known to be highly clonal. Individual pairwise crosses of synchronously spawning genotypes of each species were conducted by combining aliquots of gamete bundles immediately after spawning, and showed high and significant variability in fertilization success. Over half of the individual crosses of O. faveolata and about one-third of A. palmata crosses yielded ≤ 40% fertilization. Total sperm concentration was quantified in only a subset of O. faveolata crosses (range of 1–6 × 107 mL−1), but showed no correlation with fertilization success. We interpret that both parental incompatibility and individual genotypes with low-quality gametes are likely to have contributed to the variable fertilization observed with important implications for conservation. Differential fertilization success implies effective population size may be considerably smaller than hoped and population enhancement efforts need to incorporate many more parental genotypes at the patch scale to ensure successful larval production than indicated by estimates based simply on preserving levels of standing genetic diversity. [ABSTRACT FROM AUTHOR]

Coral reefs in Moorea, French Polynesia, suffered catastrophic coral mortality through predation by Acanthaster planci from 2006 to 2010, and Cyclone Oli in 2010, yet by 2015 some coral populations were approaching pre-disturbance sizes. Using long-term study plots, we quantified population dynamics of spawning Pocillopora spp. along the north shore of Moorea between 2010 and 2014, and considered evidence that population recovery could be supported by self-seeding. Results scaled up from study plots and settlement tiles suggest that the number of Pocillopora spp. colonies on the outer reef increased 1,890-fold between 2010 and 2014/2015, and in the back reef, 8-fold between 2010 and 2014/2015. Assuming that spawning Pocillopora spp. in Moorea release similar numbers of eggs as con-generics in Hawaii, and fertilization success is similar to other spawning corals, the capacity of Pocillopora spp. to produce larvae was estimated. These estimates suggest that Pocillopora spp. in Moorea produced a large excess of larvae in 2010 and 2014 relative to the number required to produce the recruits found in the back reef and outer reef in 2010 and 2014, even assuming that ∼99.9% of the larvae do not recruit in Moorea. Less than a third of the recruits in one year would have to survive to produce the juvenile Pocillopora spp. found in the back and outer reefs in 2010 and 2014/2015. Our first order approximations reveal the potential for Pocillopora spp. on the north shore of Moorea to produce enough larvae to support local recruitment and population recovery following a catastrophic disturbance.

Sampling mobile zooplankton on reefs is a major challenge, mainly due to the problems faced when towing plankton nets inside complex reef mosaics. This study presents two new systems that permit precise point sampling of micro- and mesozooplankton and larvae of invertebrates and fish: the Channel Midwater Neuston Net (CMNN) and the Reef Edge Net (REN). Both are moored systems that are equipped with 64- and 300-μm mesh nets. The CMNN system was designed for continuous sampling in tidal channels between reef patches. It samples at three precise depth layers (epineuston: 0 m to 0.075 m, hyponeuston: 0.075 m to 0.225 m, 1 m layer: 0.925 m to 1.075 m depth). The REN system allows sampling at precise, adjustable depths at given distances from the reef edge. The objective of the REN is to collect organisms that are washed from reef tops and reef edges with the ebb flow. The performance of these two new systems was evaluated and compared with results obtained by using common Ring nets in horizontal subsurface tows. Fieldwork was performed at two reef patches of the Tamandaré reef system (Brazil) in November 2015. The CMNN and REN showed similar performance in comparison with Ring net tows, capturing microzooplankton communities as well as veliger, polychaete, decapod and barnacle larvae in similar abundances. For the mesozooplankton, the REN presented a similar performance to the Ring net tows, efficiently capturing decapod crustacean and fish larvae as well as fish eggs. The CMNN showed lower abundance of decapod larvae and fish eggs but showed a good performance for the quantification of fish larvae. The two new passive nets showed a high effectiveness in collecting larvae and advantages over tows with Ring nets since they stay for several hours continuously capturing larval aggregations during spawning events. This high capturing efficiency is probably related to the avoidance of sample reflux in the long nets that sink and close at slack tide for the CMNN, and due to the long, trap-like design with funnel-shaped internal “anti-reflux” nets, for the REN. Navigation safety and easy handling are further advantages of these moored systems, as compared to towing plankton nets at nighttime between reefs. CMNN and REN may become useful tools for the study of zooplankton and larval ecology and for integrated long-term studies in marine protected areas and reefs under multiple human impacts. [ABSTRACT FROM AUTHOR]

This experiment aims to study the effect of different levels of salinity (5, 15 and 25 ppt) using artificial sea water on the embryonic development and hatching percentage of the eggs of unripe berried female giant freshwater prawns (Macrobrachium rosenbergii) with an average size of 14.3+0.6 cm TL. After incubation through the heart beating stage (grayish black eggs), the brooders in each salinity were separately transferred to the hatching tank with 15 ppt saline water for the second part of the study. After hatching, the healthy larvae from the brooders which were previously incubated in 3 levels of salinity were collected for the larviculture experiment. The closed recirculating water system with trickling filter unit packed with fiberglass and bioballs was used as incubation and larviculture units. The metamorphosis period and survival rate were examined. The rearing water from each larviculture aquarium was collected for determination of sodium, magnesium, potassium, calcium and chloride ions. The result showed that the percentage of ripe berried females (with heart beating stage embryos) were not significantly different (p>0.05) between 5 and 15 ppt salinity but their values were significantly higher (p0.05) in the survival rate of post larvae and metamorphosis period among the treatments. The first post larvae stage occurred on the 26th day. During 30 days of larviculture, the survival rate of all treatments was 100% until the 19th day, after which it suddenly decreased. When the concentrations of the ions in the rearing water were determined in all treatments, it was found that the concentration of magnesium ions rapidly declined (p0.05). The low survival rate during the final stage of larviculture might be due to the depletion of the previously mentioned ions especially that of magnesium.

We examined the effect of dietary arachidonic acid (ARA) and eicosapentaenoic acid (EPA) on the production of embryos and hatched larvae in the European eel, Anguilla anguilla. Two diets with high and intermediate levels of ARA and low and intermediate levels of EPA (Feed 1: ARA 1.9%, EPA 4.2%; Feed 2: ARA 1.2%, EPA 5.1% of total fatty acids) were tested against a commercial diet (DE: ARA: 0.5%, EPA: 8.2% of total fatty acids). After 24 weeks of feeding, ARA levels in the muscles and ovaries increased to 0.9% and 1.3% of total fatty acids, respectively, in Feed 1 and were significantly higher than in Feed 2 and DE. Female broodstock was not fed during hormonal treatment to induce vitellogenesis and ovulation. EPA levels in females fed the test diets decreased in the both muscle and ovary and were significantly lower in eggs from females fed Feed 1. The highest percentage of stripped females, producing viable eggs and larvae, were those females fed the highest dietary ARA levels (Feed 1). The level of lipid peroxidation products in eggs was similar among treatment, indicating that the lowest dietary levels of vitamin C and vitamin E were sufficient. In the unfertilized eggs, ARA levels were also highest (1.1% of total fatty acids) in the diet with highest ARA levels (Feed 1). [ABSTRACT FROM AUTHOR]

Adaptive Trials for Intensive Clarias gariepinus fingerling to Rural Conditions. Artificial reproduction and fingerling production of the African catfish Clarias gariepinus (Burchell 1822) have been tested under less controlled conditions to adapt the intensive technology used by Aquafarm (Tihange, Belgium) to rural conditions present in developing countries. The main aim was to compare the efficiency of ovaprim a synthesised hormone with catfish pituitary extracts. Fecundity and quality of eggs (egg weight) were not significantly different. Incubation results on water hyacinth and on mosquito mesh frames were compared to those obtained in Zoug jars; the latter showed a higher hatching rate (67%) than water hyacinth (39%) and mosquito mesh frames (44%). Larvae were stocked at different stocking rates in ponds (T1: 800 larvae.m-3 and T2: 1600 larvae. m-3 ) and in tanks (T3: 3200 larvae.m-3 et T4: 6400 larvae.m-3). After a 50-day nursing period, no significant difference (P> 0.05) was observed for specific growth rate (SGR) and survival rate, but better SGR were observed in ponds (18.34%.d-1) than in tanks (16.81%.d-1). In general, production was slightly higher in tanks than in ponds being related to a higher stocking density. Significantly higher harvests were obtained from tanks with higher stocking densities but the sizes of the larvae were very heterogeneous. In such case, it is recommended to grade the larvae at 6 or 7 days intervals using different mesh sizes (from 3 to 5 mm). These less intensive rearing conditions gave nevertheless good fingerling productions.

The spider crab Maja brachydactyla is an important fisheries species in Europe. Adults were sampled in Ría de A Coruña ( NW Spain) and transported to IRTA rearing facilities. Salinity and photoperiod changes and their effect on reproduction were tested in the laboratory. The number of newly hatched larvae per batch (presence of actively swimming newly hatched larvae in a broodstock tank) was counted and sampled to estimate dry weight and proximal composition. Keeping spider crab broodstock in a high salinity environment (38 ppt) significantly reduced the number of newly hatched larvae, reaching up to fivefold difference in winter. The number of newly hatched larvae produced under a natural photoperiod was 10-fold higher than those produced using a fixed photoperiod at 34 ppt salinity during winter. No clear pattern of changes in larval dry weight, protein, lipid or carbohydrate composition was observed under the environmental conditions tested. The results show that the salinity used for broodstock maintenance, especially during the embryonic development, is an important factor causing changes in larval production of M. brachydactyla and with potential implications for recruitment success. [ABSTRACT FROM AUTHOR]

Many snow crab fisheries have fluctuated widely over time in a quasi-cyclic way due to highly variable recruitment. The causes of this variability are still debated. Bottom-up processes related to climate variability may strongly affect growth and survival during early life, whereas top-down predator effects may be a major source of juvenile mortality. Moreover, intrinsic density-dependent processes, which have received much less attention, are hypothetically responsible for the cycles in recruitment. This study explored how climate, larval production, intercohort cannibalism and groundfish predation may have affected recruitment of early juvenile snow crab in the northwest Gulf of St Lawrence (eastern Canada) over a period of 23 years. Abundance of early juvenile snow crabs (2.5-22.9 mm in carapace width), representing the first 3 years of benthic life, came from an annual trawl survey and was used to determine cohort strength. Analyses revealed a cyclic pattern in abundance of 0+ crabs that may arise from cohort resonant effects. This pattern consisted of three recruitment pulses but was reduced to two pulses by age 2+, while the interannual variability of cohort strength was dampened. This reconfiguration of the earliest recruitment pattern was dictated primarily by bottom water temperature and cannibalism, which progressively overruled the pre-settlement factors of larval production and surface water temperature that best explained abundance of 0+ crabs. The results strongly suggest that bottom-up and density-dependent processes prevail over top-down control in setting the long-term trends and higher-frequency oscillations of snow crab early recruitment patterns. [ABSTRACT FROM AUTHOR]

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Copyright of Universidad & Ciencia is the property of Universidad Juarez Autonoma de Tabasco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article reports on the result of a study which explores the larval connectivity patterns in the Southern California Bight through the use of two quantities, such as potential and realized larval connectivity. Result of the study founds that connectivity patterns are both heterogeneous, with locations having different source and destination strengths, and asymmetric, with directionality in larval transport. Moreover, it shows that the length and timing of the spawning season as well as planktonic larval duration influences both potential and realized connectivity.

The present work evaluates the influence of broodstock diets [Marine Cuisine®– MC, MC supplemented with highly unsaturated fatty acid- (HUFA) enriched Artemia biomass – MC + AB, and MC supplemented with squid – MC + S] on larval production, newly hatched and early zoeal stage survival and fatty acid profile of newly hatched larvae of Lysmata amboinensis. These parameters are compared with those from larvae hatched from embryos spawned in the wild. The number (±SE) of larvae produced with MC and MC + S (1077 ± 219 and 1103 ± 184, respectively) was similar to that in broodstock carrying embryos spawned in the wild (1224 ± 111), while those fed MC + AB displayed significantly lower values (1044 ± 161). Larvae produced with MC + AB displayed lower survival for all starvation periods, while larvae spawned in the wild displayed the highest survival. No larvae resisted 144 h of starvation and none moulted to zoea II. The fatty acid comparison revealed that larvae from embryos spawned in the wild displayed the highest levels of DHA, as well as higher DHA/EPA and n-3/ n-6 ratios. These results suggest that broodstock diets commonly used to promote ornamental shrimp’s maturation (based on mixed frozen components) are far from being optimal. [ABSTRACT FROM AUTHOR]

Abstract: To better understand the role of the German Bight (GB) as a nursery area for juvenile North Sea sprat Sprattus sprattus we sought to determine whether the area may receive only locally or also externally produced offspring. We sampled juveniles during 3 trawl surveys in the GB in August, September, and October 2004 and applied otolith microstructure analysis in order to reconstruct their distributions of the day-of-first-increment-formation (dif). These were contrasted with spatial and seasonal patterns of sprat egg abundance in the GB and its adjacent areas, observed during 6 monthly plankton surveys. It was found that the majority of juveniles originated mainly from April/May 2004, coinciding with high spawning activity west of the GB, whereas spawning and larval production inside the GB peaked notably later, in May/June. This indicated that a large proportion of juveniles was produced outside the GB and transported subsequently into it through passive and/or active migration. Shifts to later mean difs from one survey to the next and length distributions indicative of the simultaneous presence of multiple cohorts, supported the notion that the GB is a complex retention and nursery area for sprat offspring from different North Sea spawning grounds and times. Later born juveniles had significantly faster initial growth rates than earlier born conspecifics, which was likely temperature-mediated, given the strong correlation between back-calculated growth histories and sea surface temperature as a proxy for thermal histories of juveniles (r 2 =0.52). [Copyright &y& Elsevier]

To predict changes in species’ distributions due to climate change we must understand populations at the poleward edge of species’ ranges. Ecologists generally expect range shifts under climate change caused by the expansion of edge populations as peripheral conditions increasingly resemble the range core. We tested whether peripheral populations of two contrasting butterflies, a small-bodied specialist ( Erynnis propertius) and a large-bodied generalist ( Papilio zelicaon), respond favorably to warmer conditions. Performance of populations related to climate was evaluated in seven peripheral populations spanning 1.2° latitude (160 km) using: (1) population density surveys, an indirect measure of site suitability; and (2) organismal fitness in translocation experiments. There was evidence that population density increased with temperature for P. zelicaon whose population density declined with latitude in 1 of 3 sample years. On the other hand, E. propertius showed a positive relationship of population density with latitude, apparently unrelated to climate or measured habitat variables. Translocation experiments showed increased larval production at increased temperatures for both species, and in P. zelicaon, larval production also increased under drier conditions. These findings suggest that both species may increase at their range edge with warming but the preference for core-like conditions may be stronger in P. zelicaon. Further, populations of E. propertius at the range boundary may be large enough to act as sources of colonists for range expansions, but range expansion in this species may be prevented by a lack of available host plants further north. In total, the species appear to respond differently to climate and other factors that vary latitudinally, factors that will likely affect poleward expansion. [ABSTRACT FROM AUTHOR]

Recruitment at age 2 plotted against spawning stock biomass (SSB) for the Blackwater herring stock shows a dome-shaped pattern. This has been apparent in recent years (1991–1995) when, despite high spawning stock biomass, resulting year classes have been poor. In 1994, 1996 and 1997 plankton surveys were undertaken in the Blackwater Estuary to estimate the production of yolk-sac larvae. The results of production, average cohort growth and mortality were compared with the results from surveys carried out in 1979 when spawning stock biomass (SSB) was close to the minimum historically recorded. In each year of the present study, estimated levels of larval production were higher than in 1979. Following hatching, average cohort growth rates appeared to be similar to those in 1979 but mortality rates appeared to be greater. Levels of larval production increased linearly with spawning stock biomass but there was an inverse relationship between estimated survival from hatching to recruitment at age 2 and the level of larval production. The results suggest that, in the years studied, year-class strength was determined by density dependent and/or environmental processes operating after hatching as opposed to processes operating at the egg stage. [ABSTRACT FROM PUBLISHER]

Coral reefs in Moorea, French Polynesia, suffered catastrophic coral mortality through predation by Acanthaster planci from 2006 to 2010, and Cyclone Oli in 2010, yet by 2015 some coral populations were approaching pre-disturbance sizes. Using long-term study plots, we quantified population dynamics of spawning Pocillopora spp. along the north shore of Moorea between 2010 and 2014, and considered evidence that population recovery could be supported by self-seeding. Results scaled up from study plots and settlement tiles suggest that the number of Pocillopora spp. colonies on the outer reef increased 1,890-fold between 2010 and 2014/2015, and in the back reef, 8-fold between 2010 and 2014/2015. Assuming that spawning Pocillopora spp. in Moorea release similar numbers of eggs as con-generics in Hawaii, and fertilization success is similar to other spawning corals, the capacity of Pocillopora spp. to produce larvae was estimated. These estimates suggest that Pocillopora spp. in Moorea produced a large excess of larvae in 2010 and 2014 relative to the number required to produce the recruits found in the back reef and outer reef in 2010 and 2014, even assuming that ∼99.9% of the larvae do not recruit in Moorea. Less than a third of the recruits in one year would have to survive to produce the juvenile Pocillopora spp. found in the back and outer reefs in 2010 and 2014/2015. Our first order approximations reveal the potential for Pocillopora spp. on the north shore of Moorea to produce enough larvae to support local recruitment and population recovery following a catastrophic disturbance., Competing Interests: The authors declare there are no competing interests.