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There is considerable interest in improving hatchery production of the mud crab, Scylla serrata. Although some progress has been made toward identifying appropriate feeding protocols for live-foods, the density at which food is first provided to larvae varies greatly in practice. This study examined relationships between rotifer density and activity patterns of enzymes critical to digestion in S. serrata to evaluate feeding protocols from a nutrient utilization perspective. Activities of trypsin-like proteases, nonspecific esterases, and [alpha]-amylase were quantified to determine the response of newly hatched (Zoea I) larvae of S. serrata to rotifers provided at four different densities (i.e., 10, 20,40, and [80mL.sup.-1]) from first-feeding. Results showed that rotifer density significantly (P < 0.01) influenced total activity (mU [larva.sup.-1]) patterns within 24h of first-feeding for all the enzymes assayed. Based on these patterns, utilization of the associated macronutrients (i.e., protein, lipid, and carbohydrate) was presumably similar when larvae were provided with rotifers at densities of 10, 20, or 40 [mL.sup.-1] and increased when larvae were provided with rotifers at a density of 80 [mL.sup.-1]. An optimal density at which to provide rotifers to S. serrata for first-feeding is likely to be >[40mL.sup.-1]. The comparative analyses of enzyme activities presented in this study represent an innovative approach to quickly (within 24 h) identify optimal food densities for larval crustaceans at first-feeding. KEY WORDS: Portunidae, Scylla serrata, mud crab, hatchery production, first-feeding, rotifers, enzyme activity patterns, INTRODUCTION Crabs of the genus Scylla, commonly referred to as mud crabs, have a complex life cycle, where larvae progress through five to six zoeal stages (3-5 days each) and [...]

As the global human population grows, it remains a top priority for communities, managers, policymakers, and stakeholders to maintain healthy, sustainable, and productive fisheries under continued global change. Here we used a dataset consisting of fish and lake characteristics for 536 lakes across Ontario, Canada, to test whether multiple climate, human, and biological factors differentially affect fish production (i.e., population biomass per hectare per year). We tested the hypothesis that temperature is the key driver of fisheries production by testing for the effects of multiple factors on the production of three top predatory fish species: cold-water lake trout (Salvelinus namaycush), cool-water walleye (Sander vitreus), and warm-water smallmouth bass (Micropterus dolomieu). Using boosted regression tree analyses, we found that lake trout production was most influenced by the volume of hypolimnetic habitat, walleye production was related to other climatic variables, and smallmouth bass production was most influenced by sampling day of the year followed by Secchi depth. Our results suggest that current fish production models--that only include temperature and body size--may oversimplify important ecological complexities and thus misinform management decisions because species respond differently to environmental drivers. Pour faire face a la croissance demographique mondiale, les communautes, gestionnaires, decideurs et parties prenantes doivent continuer de prioriser le maintien de ressources halieutiques saines, durables et productives dans un contexte de changements climatiques. Nous avons utilise un ensemble de donnees constitue de caracteristiques de poissons et de lacs pour 536 lacs en Ontario (Canada) pour verifier si divers facteurs climatiques, humains et biologiques exercent differents effets sur la production de poissons (c.-a-d. la biomasse de la population par hectare par annee). Nous avons verifie l'hypothese voulant que la temperature soit le principal facteur qui module la production des peches en examinant les effets de differents facteurs sur la production de trois especes de predateurs de niveau trophique superieur, a savoir le touladi (Salvelinus namaycush), une espece d'eau froide, le dore jaune (Sander vitreus), une espece d'eau fraiche, et l'achigan a petite bouche (Micropterus dolomieu), une espece d'eau chaude. En utilisant des analyses par arbre de regression augmente, nous constatons que le volume des habitats hypolimnetiques exerce la plus forte influence sur la production des touladis, que la production de dores jaunes est associee a d'autres variables climatiques et que la date d'echantillonnage, suivie de la profondeur mesuree par le disque de Secchi, influencent le plus la production d'achigans a petite bouche. Nos resultats donnent a penser que les modeles de production de poissons actuels, qui n'integrent que la temperature et la taille du corps, pourraient trop simplifier d'importantes complexites ecologiques et ainsi produire des decisions de gestion non optimales decoulant du fait que les especes ne repondent pas toutes de la meme maniere a differents facteurs environnementaux. [Traduit par la Redaction], Introduction The global human population is expected to reach 9.7 billion by the year 2050 (United Nations 2019), which will put continued stress on our freshwater ecosystems and the services [...]

Warming waters are changing marine pathogen dispersal patterns and infectivity worldwide. Coupled biological--physical modelling has been used in many systems to determine the connectivity of metapopulations via infectious disease particles. Here we model the connectivity of sea lice larvae (Lepeophtheirus salmonis) among salmon farms in the Broughton Archipelago, British Columbia, Canada, using a coupled biological-physical model. The physical model simulated pathogen dispersal, while the biological component influenced the survival and developmental rates of the sea lice. Model results predicted high temporal variability in connectivity strength among farms, an emergent effect from the interacting parts of the simulation (dispersion versus survival and development). Drivers of temporal variability were disentangled using generalized additive modeling, which revealed the variability was most strongly impacted by the spring freshet, which can act as a natural aid for sea lice control in the Broughton Archipelago. Our results suggest that farm management strategies can benefit by accounting for short-term spikes in regional pathogen connectivity among farms. Additionally, future scenarios of a warming climate with reduced snowpack can make sea lice control more challenging. Le rechauffement des eaux modifie les motifs de dispersion et l'infectiosite des pathogenes marins a l'echelle planetaire. La modelisation couplee biologique-physique a ete utilisee dans de nombreux systemes pour determiner la connectivite de metapopulations par le biais de particules de maladie infectieuse. Nous modelisons la connectivite des larves de pou du poisson (Lepeophtheirus salmonis) entre des fermes salmonicoles de l'archipel Broughton (Colombie-Britannique, Canada), en utilisant un modele couple biologique-physique. Le modele physique simule la dispersion du pathogene, alors que la composante biologique influence les taux de survie et de developpement des poux du poisson. Les resultats du modele predisent une forte variabilite temporelle de la force de la connectivite entre les fermes, un effet emergent decoulant des aspects interdependants de la simulation (dispersion et survie et developpement). Les facteurs de variabilite temporelle sont demeles en utilisant un modele additif generalise, qui revele que la crue printaniere exerce la plus forte influence sur la variabilite et peut servir de mecanisme naturel pour lutter contre les poux du poisson dans l'archipel Broughton. Nos resultats donnent a penser que la prise en compte de pointes de courte duree de la connectivite regionale de pathogenes entre les fermes peut ameliorer les strategies de gestion des fermes. Les scenarios de rechauffement climatique futur et de reduction associee du manteau neigeux pourraient en outre rendre la lutte contre les poux du poisson plus difficile. [Traduit par la Redaction], Introduction Transmission of water-borne pathogens (parasites, viruses, bacteria) in marine environments depends on factors influencing the movement and viability of the pathogen. Passive dispersal depends on local hydrodynamics, as dictated [...]

Size selectivity curves were estimated for two commercial dredge configurations used in the United States Atlantic sea scallop (Placopectcn magellanicus) fishery. Traditionally, the New Bedford Style dredge (New Bedford dredge) has been used by the commercial fleet; however, since 2013, the Coonamessett Farm Turtle Deflector Dredge (turtle dredge) has been required seasonally in the Mid-Atlantic region to minimize the capture of sea turtles. This analysis provides estimates of selectivity and relative efficiency for the turtle dredge and the New Bedford dredge. Selectivity information for the turtle dredge is currently unknown, and selectivity for the New Bedford dredge was originally assessed in 2008. The Share Each Length's Catch Total method was used to model scallop catch-at-length data for each commercial dredge with data collected during the Virginia Institute of Marine Science fishery-independent surveys in 2015 to 2017, conducted onboard commercial fishing vessels. The surveys were conducted in the Mid-Atlantic and Georges Bank regions of the resource in three distinct areas. A paired study design was used, where a nonselective National Marine Fisheries Service sea scallop survey dredge and either the turtle dredge or New Bedford dredge were towed simultaneously at each survey station. To assess for time-varying changes in selectivity, results were compared with the 2008 New Bedford dredge analysis. Results indicated the 50% retention length was 98.2 mm, with a selection range of 28.2 mm and a relative efficiency of 0.83 for the turtle dredge. New Bedford dredge results estimated a 50% retention length of 107.4 mm, selection range of 50.5 mm and relative efficiency of 0.81. Comparing selectivity profiles for the turtle dredge and New Bedford dredge with the 2008 results indicated a shift toward increased retention probability for smaller size classes of scallops. KEY WORDS: selectivity, Placopecten magellanicus, sea scallop dredge fishery. New Bedford style dredge, Coonamessett Turtle Deflector Dredge, SELECT, INTRODUCTION Understanding the selective profile of fishing gear is a critical aspect of fisheries management and stock assessments. Selectivity is defined as the proportion of a population that is captured [...]

Background Intensive aquaculture farming has caused significant degradation of coastal wetlands and has been proposed as a reservoir for pathogenic Vibrio spp. Results Gut pathogens including Vibrio spp., Salmonella spp., and Klebsiella spp. were isolated from bird feces, shrimp and wetland water in two typical coastal regions of China in 2015 and 2017 and were subsequently subjected to whole-genome sequencing. Meanwhile, local patient isolates were also selected to confirm the epidemiological links. Bacterial community composition analyses of the sediments that were sampled in 2015 and 2017 were conducted by the hypervariable region 4 of the 16S rRNA gene. Together with the local clinical isolates, we observed highly related Vibrio isolates from waterbirds, wetlands and shrimp. Phylogenetic genome comparisons also demonstrated that sequence types ST3 and ST2414 Vibrio parahaemolyticus isolates obtained from aquatic animals were clonally related to patient isolates. Likewise, three Salmonella typhimurium isolates were also genomically related to one clinical strain. The results showed that farming activities significantly altered the community composition and resulted in the emergence of several pathogens, including Acinetobacter, Mycobacterium and Legionella. Conclusions In conclusion, our results demonstrated that intensive shrimp farming in wetlands has two devastating impacts: pathogen dissemination from aquatic animals into migratory birds and transmission of foodborne pathogens into local communities. Keywords: Vibrio parahaemolyticus, Vibrio vulnificus, Wetlands, One health, Shrimp farming, Author(s): Qingyao Wang[sup.1,2], Yixiang Zhang[sup.3,4], Qian Yang[sup.5], Songzhe Fu[sup.1,2], Baocheng Qu[sup.1,2] and Tom Defoirdt[sup.5] Background Destruction of animal habitats has been associated with infectious disease emergence [1-3]. For instance, the [...]

Measures of consumption and supply sources of seafood can provide valuable input to research and policy planning of a viable food system. This article fills a gap in the existing literature by mapping the existing seafood supply flows from various sources (local, domestic U.S., and foreign) in Hawaii. The authors trace the seafood transshipment of foreign origin via the continental United States to Hawaii and update total and per capita consumption of seafood more accurately by including noncommercial catches into the analysis. Per capita seafood consumption in Hawaii from all commercial sources is estimated at an annual average of 29 edible pounds during the 10-year period from 2000 to 2009. This is significantly more than the 16 edible pounds for all U.S consumption in 2009. Including noncommercial catch, the same measure increases to 37 edible pounds. The eight-pound differential suggests that noncommercial fishing is an important source of seafood supply in Hawaii. Overall, fresh tuna (Thunnus spp.) is the single largest species group consumed, followed by Pacific and Atlantic salmon (Salmonidae). By edible weight, the majority of Hawaii's commercial seafood supply comes from foreign sources (57%) vs. local sources (37%), and U.S. domestic sources (6%). The leading sources for Hawaii's direct seafood imports from 2000 to 2009, were Taiwan, Japan, New Zealand, the Philippines, and the Marshall Islands. Local supply becomes the majority source once noncommercial catch is included with 51% of the total supply., Introduction As an isolated chain of islands in the central Pacific Ocean, Hawaii is striving to redevelop a viable regional food system in the face of rising fuel prices and [...]

Byline: Kriton Grigorakis (1) Keywords: Ethics; Ethical Matrix; Seafood; Fish; Aquaculture; Sustainability Abstract: The ethical issues raised by aquaculture were analyzed. A modification of the Ethical Matrix of the Food Ethics Council for the evaluation of novel foods was used the Ethical Matrix was changed in order to include the various aquaculture production stages separately. The following stages were distinguished: the breeding stage, the growth/feeding stage, the 'other-handling' stage (that includes disease and treatment, transportation of organisms, killing procedure, and DNA vaccinations), and the commercialization stage. The ethical issues concerning the producers, the consumers, the environment, and the aquacultured organisms, are discussed. This scheme was fitted to the intensive cage-culture of carnivorous fish. The differences with other forms of aquaculture are discussed, and how the scheme extrapolates to them. The ethical evaluation of aquaculture, in practice, will be rather a utilitarian balancing of cost and benefits of the respective actions. The desired characteristics of an ethical evaluation have been also outlined. Ethical evaluation should not be limited to a purely scientific analysis it should be holistic, comparable to available alternatives, and should have the flexibility to incorporate new data generated in the fast growing/continuous changing aquaculture sector. Author Affiliation: (1) Hellenic Centre for Marine Research (HCMR), Institute of Aquaculture, Agios Kosmas, Hellinikon, 16777, Athens, Greece Article History: Registration Date: 10/09/2009 Accepted Date: 04/09/2009 Online Date: 18/09/2009

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2009.02.013 Byline: P. Vassallo (a), I. Beiso (a)(b), S. Bastianoni (c), M. Fabiano (a) Abstract: The environmental sustainability of a fish farm rearing process was examined by means of emergy analysis. Many emergy analyses integrate data for a whole year smoothing short term variations and sometimes losing meaningful information (aliasing). For this reason we developed a model for an instantaneous emergy evaluation in an aquacultural system so that transformities, efficiency and effort spent at each moment during the fish rearing activity could be calculated. By means of the model and dynamic emergy calculations it is possible to recognize step by step the importance of the various emergy contributions and verify where and when to modify the system to move toward optimum production of a sustainable product. By the application of the model we confirmed that the emergy trends in a fish farm installation follow wide oscillations during a year due to variations in both internal and external emergy contributions. Among the fluxes considered, those due to the introduction of fingerlings represented the highest contributions to the total emergy budget. Thus, to improve the sustainability of the analyzed system the amount, frequency and timing of these fluxes must be carefully considered. For this purpose, a comparison between two different fry introduction schedules was performed to evaluate differences in the efficiency of the rearing process. Author Affiliation: (a) Department for the Study of Territory and its Resources, University of Genoa, Corso Europa 26, 16132 Genoa, Italy (b) Ca' Foscari University of Venice, Island of San Servolo, 30100 Venice, Italy (c) Department of Chemical and Biosystems Sciences, University of Siena, Via A. Moro 2, Siena, Italy Article History: Received 14 April 2008; Revised 26 January 2009; Accepted 21 February 2009