Intensive Aquaculture Production Research Articles

Recovery of nutrients from fish sludge to enhance the growth of microalga Chlorella sorokiniana CMBB276

Intensive aquaculture production generates large amounts of sludge. This waste could be considered as a potential source of nutrients that can be recovered and utilized. Little attention has been paid to nutrient recovery from fish sludge. In this study, bioconversion of sludge was evaluated in lab scale under anaerobic (AN), facultative anaerobic (FA) and aerobic (AE) conditions. After 40 days of fermentation, AN recovered the highest values of dissolved total nitrogen (82.7 mg L−1), while AE showed the highest dissolved total phosphorus (11.8 mg L−1) and the highest reduction of total suspended solids (36.0 %). Microbial analysis showed that AN exhibited a distinct bacterial community than that of FA and AE. Furthermore, C. sorokiniana grown in AN effluents collected after 12 days of fermentation achieved the highest biomass production (1.96 g L−1). These results suggest that AN has the best potential to recover nutrients from sludge for production of C. sorokiniana.

Water quality change, growth performance, health status in response to dietary inclusion of black soldier fly larvae meal in the diet of Nile tilapia, Oreochromis niloticus

Abstract With increasing intensive aquaculture production, the search for nourishing, environmentally, and economically viable fishmeal (FM) alternative is an endless approach. Therefore, the present study examines the effect of the use of black soldier fly, Hermetia illucens, larvae meal (BSFM) as an alternative protein for FM in the diet of Nile tilapia, Oreochromis niloticus, on nitrogen wastes, zootechnical performance, body composition, and hematobiochemical parameters. A total of 315 Nile tilapia fingerlings (4.11±0.12 g/fish) were divided into seven treatments in triplicate. The fish were stocked in glass aquaria (50 × 40 × 30 cm; 60 L each) at a rate of 15 fish per aquarium. Experimental diets contained BSFM at increasing levels of 0, 5, 10, 15, 20, 25, and 30% as FM replacers were offered twice daily to apparent satiation for 84 days. The results revealed that BSFM replacements significantly (P = 0.001) enhance water quality and reduce the total ammonia, NH3, and NO2 levels compared to the control. The growth performance, feed conversion ratio, and survival were improved with increasing BSFM meal inclusion levels up to 25% (P = 0.001, 0.017, and 0.001, respectively). However, the zootechnical performance of the experimental fish started to decline with increasing replacement levels to 30%. Also, by an increase in BSFM level to 25%, hematobiochemical markers were considerably (P≤0.01) enhanced. The liver and kidney function indicators improved (P = 0.001) with dietary BSFM. The economic evaluation revealed that feed costs and fish weight gain were decreased by increasing BSFM levels in fish diets. The current study highlighted the potential environmentally beneficial use of BSFM as an FM replacer in terms of reducing water nitrogen waste levels and improving growth performance, health status, and enhancing the economic feasibility of the commercial tilapia diet.

The genetics and breeding of the Portuguese oyster, Crassostrea angulata: lessons, experiences, and challenges in Vietnam

Aquaculture mollusc production is predominantly from Asia, with more than 80% of the total biomass produced in China. Vietnam’s annual mollusc production is growing rapidly but is comparatively small given its coastal resources. A significant challenge for future mollusc production, and oysters in particular, is the supply of high-quality spat. Most mollusc spat in Vietnam comes from local wild sources or is imported from China. Particularly in the case of oysters, where wild collection is low and importation of oyster spat into Vietnam from other jurisdictions is not controlled, supply is unreliable and presents a biosecurity risk to the industry. Controlling the life cycle in hatcheries can increase the sustainability and reliability of spat supply with the advantages of genetic enhancement in the long term. Beyond well-established selection methods based on phenotypic data for pedigreed families, the rapid development of genomic technology has enabled innovation in hatchery production based on genetic programs. This technology allows greater insight into oyster genetics in intensive aquaculture production systems. Recent reviews of selection programs demonstrate that inbreeding control via mate selection is an effective strategy for oyster species. Genetic response through combinations of individual and family-based selection can enhance morphometric traits by 10% per generation and disease resistance by 15% per generation in many aquaculture species. Genomic techniques provide information for selecting candidates at an earlier stage and improve prediction accuracy. In this paper, we review the literature on popular genomic tools and breeding techniques used for molluscs, focusing on the Portuguese oyster, Crassostrea angulata. This is to better comprehend how modern quantitative and molecular genetic technologies are being applied in mollusc breeding programs. It considers opportunities for and the feasibility of using genomic-based selection as well as the challenges that are faced in breeding programs transitioning to these new methods.

Characterization and finding the origin of off-flavor compounds in Nile tilapia cultured in net cages in hydroelectric reservoirs, São Paulo State, Brazil

An increasing demand for fish products has led to an intensive aquaculture production in Brazil, and cultivation of fish constituted 860 × 103 tons in 2022, contributing to the 87% of total fish consumption. Nile tilapia constitutes almost half of the aquaculture production, and most tilapia farms use floating net cages. One of the major constraints of intensive fish production is production of off-flavors. Release of nutrients by the fish leads to deterioration of the water quality and stimulates growth of microorganisms, also including off-flavor producing species. The objective of this study was to determine levels of taste and odor compounds (geosmin, 2-MIB and a selection of volatile compounds) and their impact on the flavor quality of Nile tilapia produced in net cages in reservoirs in São Paulo State, Brazil. GC-MS analysis of fish and water from six different farms showed concentrations of geosmin in the water from 1 to 8 ng/L, while geosmin in fish flesh ranged from 40 to 750 ng/kg. The level of 2-MIB in water was 2 to 25 ng/L, and 0 to 800 ng/kg fish. The GC-MS analysis also revealed presence of more than 100 volatile organic compounds in the fish flesh, consisting of aldehydes, alcohols, benzene derivatives, hydrocarbons, ketones and few other compounds. Geosmin and 2-MIB related flavor notes were detected in all fish by a sensory panel, and a high correlation between the chemical and sensory analyses was found. The potential impact of the volatile organic compounds on the fish flavor is discussed. Analysis of the water quality in the reservoirs indicated that levels of geosmin and 2-MIB levels were highly influenced by the nutrient levels in the water.

Study of ammonia removal in aquaponic system with Chinese flowering cabbage (Brassica chinensis (var. parachinensis)) and mechanical filter for tilapia cultivation

Water quality is one of the important factors to increase the success of fish farming production apart from disease factors and fish seed quality. Oreochromis niloticus or commonly called tilapia is one of the fish that is widely cultivated in Indonesia. The challenges of increasing intensive aquaculture production are stocking density and high protein feed while maintaining good water quality. High stocking densities and high protein feed can increase ammonia in the water which can cause death in fish, for that some quality control of aquaculture can be done, namely using mechanical filters (Granular activated carbon and biofoam) and aquaponic. The difference between these two methods was in the media used, mechanical filters used granular activated carbon and biofoam, while aquaponics used Chinese flowering cabbage (caisin) (Brassica chinensis var. parachinensis). To determine the effectiveness of reducing ammonia from the two methods, this study will compare water quality parameters with mechanical filters and aquaponic filter methods by using plant medi, namely (Brassica chinensis var. parachinensis). This research was conducted for 30 days to measure several water quality parameters including temperature, DO, pH, TDS and total ammonia nitrogen (TAN). The results during the study showed that the recirculating aquaponic system was better than the recirculating system with a mechanical filter (Granular activated carbon and biofoam) for SR, FCR and TDS parameters while the temperature, pH, DO and TAN parameters for 30 days were not much different between the recirculating aquaponic system and the recirculating system using a mechanical filter (Granular activated carbon and biofoam).

A Study on the Metabolic Rate Change Pattern in F2 Hybrid Sturgeon, the Bester (Huso huso × Acipenser ruthenus), during the Early Developmental Stage

The primary goal in aquaculture is to maximize the growth and survival of farmed fishes at a minimal cost, which requires an understanding of the changes in metabolism undergone by different fish breeds during development. In particular, highly intensive aquaculture production systems, such as recirculating aquaculture systems, require a better understanding of oxygen consumption. Ontogenetic phase shifts (i.e., sudden changes) in metabolism have been observed in several aquaculture species during early development, and such metabolic phase shifts may help to predict the oxygen consumption of aquaculture species during different stages of their development. Here, I analyzed the pattern of metabolic changes in the F2 hybrid sturgeon, the bester (Huso huso × Acipenser ruthenus; hereafter, referred to as the F2 bester), during its early development. I observed ontogenetic phase shifts in metabolism in the F2 bester at body mass values of about 0.2 and 0.8 g. Thus, the F2 bester undergoes ontogenetic phase shifts in metabolism during early development, which can help to characterize oxygen consumption at a specific developmental period. Therefore, oxygen can be appropriately adjusted and replenished during breeding.

Water quality image classification for aquaculture using deep transfer learning

With the development of high-density and intensive aquaculture production and the increasing frequency of water quality changes in aquaculture water bodies, the number of pollution sources in aquaculture ponds is also increasing. As the water quality of aquaculture ponds is a crucial factor affecting the production and quality of pond aquaculture products, water quality assessment and management are more important than in the past. Water quality analysis is a crucial way to evaluate the water quality of fish farming water bodies. Traditional water quality analysis is usually obtained by practitioners through experience and visual observation. There is an observability deviation caused by subjectivity. Deep transfer learning-based water quality monitoring system is easier to deploy and can avoid unnecessary duplication of efforts to save costs for aquaculture industry. This paper uses the transfer learning model of artificial intelligence to analyze the water color image automatically. 5203 water quality images are collected to create a water quality image dataset, which contains five classes based on water color. Based on the dataset, a deep transfer learning-based classification model is proposed to identify water quality images. The experimental results show that the deep learning model based on transfer learning achieves 99% accuracy and has excellent performance.

Effects of open water availability on productivity and efficiency of tilapia fish farming

Intensive pond aquaculture production is increasing and playing a major role in global aquaculture production, especially in developing countries. Empirical evidence shows that the access to and exchange of fresh water in tilapia pond aquaculture is important for making pond production ecologically more sound, efficient and productive. This study investigates productivity and efficiency differences between farms with access to open water resources and farms without access using data obtained from 311 interviews with tilapia farmers in Bangladesh. Propensity Score Matching (PSM) and meta-frontier DEA have been employed to estimate productivity and efficiency differences between the groups. Results show that farms located in areas with access to open water resources are significantly more efficient, but a bit surprisingly less productive than farms located in areas with deficit access to water resources. Furthermore, output could be increased by 29% and 40% without increasing input in areas with good access and limited access to water, respectively. Thus, promoting intensive aquaculture pond production in areas with access to water resources should focus on how to increase productivity, while areas with limited access should focus on optimal use of input in order to improve water quality and efficiency.

Spatial Analysis for Mariculture Site Selection: A Case Study of Kukup Aquaculture Zones in the Peninsula of Malaysia

Marine aquaculture sites at Kukup Strait in the peninsula of Malaysia are experiencing a decline in water quality in the last five years, resulting in high mortality rates (50 - 80%), seasonal massive fish mortalities and poor profitability. Currently, Kukup farmers are involved in intensive aquaculture within the existing aquaculture zone. This study explores the sustainability of a modern mariculture method, where fish farms are relocated to deeper waters with higher flushing rates, and high-density polyethylene (HDPE) are used to improve water quality. Several site selection criteria are utilised in identifying the proposed aquaculture industrial zone: 1) bathymetry depth (operational requirement: 10 m to 30 m), 2) located within the Kukup Port Limit, 3) does not interfere with the Kukup ferry navigation route, and 4) distance from Kukup mainland. Site feasibility analysis, including hydrodynamics, meteorology, water quality, sediment quality and macrobenthos assessment, was conducted to compare the proposed and existing aquaculture sites. It was found that the water quality at the existing site contained higher concentrations of fecal coliform and nutrients and salinity fluctuations. Tropical finfish can survive under these conditions with poorer fish health and higher fish mortality. Apart from that, the flushing capacity is higher in the proposed site, indicating the capacity to handle moderate-intensity aquaculture. Moderate-intensity aquaculture using HDPE cages could be profitable for the local fish farmers. Therefore, it is suggested that other locations within Kukup Straits with deeper waters (> 25 m) with possibly improved water quality and the ability for intensive aquaculture production should be explored for a larger depth and economics of scale.

Economic Viability of Cassava Residues in the Nile Tilapia Diet

Fish feed represents between 50% and 70% of intensive aquaculture production costs. In this context, the present study aimed to evaluate the economic viability of the production of Nile tilapia under a diet with cassava residues in it. To evaluate the economic efficiency in relation to the inclusion of residues in the tilapia feed, the approximate cost of feed per kilogram of live weight (CMR) gained during the experimental period was determined, and later the cash flow of the production was raised for analysis of indicators: NPV (Net Present Value), CBI (Cost Benefit Rate), and IRR (Internal Rate of Return) submitted to different discount rates from existing financing sources in the region. It was found that tilapia under the diet with the inclusion of tapioca sweep in the diet, showed greater economic efficiency, and consequently higher NPV (R $ 4,583.33), IRR (15%) and CBR (1.17). In this sense, the viability analysis showed that cassava residues in diets of tilapia diets, indicate to be a viable strategy to better develop aquaculture production, in a more sustainable way, enhancing the technical and economic viability and minimizing the environmental impacts.

Total replacement of dietary fish oil with vegetable lipid sources influenced growth performance, whole body composition, and protein retention in Nile tilapia (Oreochromis niloticus) fingerlings

ABSTRACT Several reports show that aquaculture is the fastest food-producing sector globally, contributing nearly half of global fish production from all sectors. However, there has been a steady decline in production of fish oil (FO), which supports intensive aquaculture production. This has resulted in variable but generally increasing prices of FO. Finding suitable alternatives to scarce FO is essential for aquaculture sustainability. Therefore an experiment was carried out to investigate the influence of complete FO substitution with vegetable oil (VO) in the diet of Oreochromis niloticus fingerlings on growth performance, whole-body composition, and protein retention. Four isonitrogenous (30% crude protein), isolipidic (8% crude lipid), and isocalorific (17 MJ kg−1gross energy) basal diets were formulated as follows: a control diet was formulated to contain 5% FO and labeled FOD (fish oil diet), and three other diets were formulated and labeled SOD (soya oil diet), GOD (groundnut oil diet), and POD (palm oil diet); they contained soya oil (SO), groundnut oil (GO), and palm oil (PO) respectively as total replacements for FO. Triplicate O. niloticus fingerlings (N = 120, n = 10, 1.20 ± 0.03 g, mean weight ± SD) were randomly allocated to one of four experimental diets. Fish were hand-fed to apparent satiation twice daily for 63 days. The result obtained from the experiment revealed that dietary lipids significantly influenced growth performance and nutrient utilization of O. niloticus (P < 0.05). The fish fed POD had the least weight gain (WG) and highest feed conversion ratio (FCR) compared with fish fed FOD, SOD, and GOD from days 7–28 (P < 0.05). At day 35 the fish fed SOD had the highest WG (P < 0.05); fish fed GOD had the least WG. The best weekly overall growth at the end of day 56 was observed in fish fed FOD; fish fed POD had the least WG. At day 63, WG of fish fed FOD declined significantly compared to fish fed GOD, POD, and SOD, which had the best growth. At the end of the trial, the best cumulative growth in fish was observed for fish fed FO; however, there were no significant differences (P < 0.05) in WG and FCR between fish fed FOD and SOD. Survival was 100% for all treatments. Fish fed POD exhibited significantly lower levels of whole-body protein compared to fish fed FOD, SOD, and GOD. Fish fed a diet containing FO had the highest (P < 0.05) whole protein compared to diets with VO. However, no significant difference (P < 0.05) between whole-body protein of fish fed FOD and SOD was observed. Fish fed SOD had the highest (P < 0.5) body lipid compared with fish fed the FO, GO, and PO diets. In conclusion, the study has demonstrated that VO can completely replace FO in Nile tilapia diet without affecting growth performance of O. niloticus and that tilapia diet containing SO is a better alternative to FO compared to GO and PO. These findings are useful in dietary formulation to reduce feed costs without compromising tilapia fish growth.

Plant-Produced Vaccines: Future Applications in Aquaculture.

Aquaculture has undergone rapid development in the past decades. It provides a large part of high-quality protein food for humans, and thus, a sustainable aquaculture industry is of great importance for the worldwide food supply and economy. Along with the quick expansion of aquaculture, the high fish densities employed in fish farming increase the risks of outbreaks of a variety of aquatic diseases. Such diseases not only cause huge economic losses, but also lead to ecological hazards in terms of pathogen spread to marine ecosystems causing infection of wild fish and polluting the environment. Thus, fish health is essential for the aquaculture industry to be environmentally sustainable and a prerequisite for intensive aquaculture production globally. The wide use of antibiotics and drug residues has caused intensive pollution along with risks for food safety and increasing antimicrobial resistance. Vaccination is the most effective and environmentally friendly approach to battle infectious diseases in aquaculture with minimal ecological impact and is applicable to most species of farmed fish. However, there are only 34 fish vaccines commercially available globally to date, showing the urgent need for further development of fish vaccines to manage fish health and ensure food safety. Plant genetic engineering has been utilized to produce genetically modified crops with desirable characteristics and has also been used for vaccine production, with several advantages including cost-effectiveness, safety when compared with live virus vaccines, and plants being capable of carrying out posttranslational modifications that are similar to naturally occurring systems. So far, plant-derived vaccines, antibodies, and therapeutic proteins have been produced for human and animal health. However, the development of plant-made vaccines for animals, especially fish, is still lagging behind the development of human vaccines. The present review summarizes the development of fish vaccines currently utilized and the suitability of the plant-production platform for fish vaccine and then addresses considerations regarding fish vaccine production in plants. Developing fish vaccines by way of plant biotechnology are significant for the aquaculture industry, fish health management, food safety, and human health.

Design of an Intelligent Variable-Flow Recirculating Aquaculture System Based on Machine Learning Methods

A recirculating aquaculture system (RAS) can reduce water and land requirements for intensive aquaculture production. However, a traditional RAS uses a fixed circulation flow rate for water treatment. In general, the water in an RAS is highly turbid only when the animals are fed and when they excrete. Therefore, RAS water quality regulation technology based on process control is proposed in this paper. The intelligent variable-flow RAS was designed based on the circulating pump-drum filter linkage working model. Machine learning methods were introduced to develop the intelligent regulation model to maintain a clean and stable water environment. Results showed that the long short-term memory network performed with the highest accuracy (training set 100%, test set 96.84%) and F1-score (training 100%, test 93.83%) among artificial neural networks. Optimization methods including grid search, cuckoo search, linear squares, and gene algorithm were proposed to improve the classification ability of support vector machine models. Results showed that all support vector machine models passed cross-validation and could meet accuracy standards. In summary, the gene algorithm support vector machine model (accuracy: training 100%, test 98.95%; F1-score: training 100%, test 99.17%) is suitable as an optimal variable-flow regulation model for an intelligent variable-flow RAS.

Animal Welfare Issues in Capture-Based Aquaculture.

Simple SummaryAquaculture is about farming aquatic animals in certain facilities, in order to meet the global demand for aquatic animal products. However, reproduction and raising of all commercially important aquatic animals under farming conditions are not always feasible or cost-effective. Thus, for some fish and shellfish species, a system that relies on the collection of wild individuals, at various life stages and rearing in controlled facilities, has been employed. These animals, however, are not products of a lengthy domestication process and thus are not used to the artificial environment of the fish farms. The way they respond to the various stressful conditions might be different, compared to the domesticated fish. Therefore, we have to make sure that we use the appropriate rearing methods, for the entire time, so that their impact on the fish welfare is minimized. Apart from the moral obligations, this will also increase the profitability of the activity.Capture-based aquaculture (CBA) represents a type of intensive aquaculture production system for some economically valuable fish species, such as bluefin tuna (Thunnus thynnus), eel (Anguilla spp.) and Atlantic cod (Gadus morhua). In CBA, fish are captured from the wild in certain periods of the year, and following a recovery phase, they are kept in rearing facilities for a period of time, until they reach the market size. In this case, the fish are wild and have not gone through domestication like other fish species that are reproduced and farmed under the established farming systems. Therefore, these fish are not genetically adapted to live under the intensive farming conditions, and thus their welfare may be compromised in different manners compared to their domesticated counterparts. This review presents an overview of the current situation of CBA, while focusing on the assessment of fish welfare in CBA. The most commonly used fish welfare indicators will be discussed in relation to the different stages of CBA.

Digital transformation model based on the digital twin concept for intensive aquaculture production using closed water circulation technology

The article discusses the complex digital transformation problem for the functioning aqua-biotechnological industrial company. The structure of the information model and digital twin for such objects is identified and described. The results of a comprehensive engineering and economic inspection of the state of the biotechnological, engineering, and economic system from the point of view of digital transformation are described. A conceptual scheme of the enterprise functioning based on the results of digital transformation is presented. The target effects of modernization and reconstruction of the existing biotechnological enterprise based on the end-to-end digital technologies of the fourth industrial revolution are formulated.

Determination of Opportunistic Pathogens and Antimicrobial Resistance Characterization Isolated From Rainbow Trout in Turkey

Modern aquaculture enables effective means for intensive aquaculture production under “controllable” conditions. This rapidly growing industry, however, has experienced relatively severe disease problems owing to a lack of control of the microbiota in rearing systems. In the present study, we identified the opportunistic pathogens and some members of natural microbiota, which were obtained from our culture collection by culturable methods and characterized biochemically in addition to molecular analysis. All isolates were identified by gene sequence analysis and confirmed taxonomically in the bacterio.net database. The isolates were characterized by means of antimicrobial susceptibilities by broth microdilution method analysis, and the resistance gene determinants were screened by PCR analysis. A total of 14 species were identified with high genetic similarity in the GenBank database. MIC results showed that bacteria have heterogeneous characteristics for the susceptibility of an agent into the genus, and species have high MIC values for sulfamethoxazole, trimethoprim, and ampicillin comparing to other agents. A total of 13 different resistance genes were determined in the bacteria, and some of them have multiple resistance genes up to five genes.

Achieving sustainable aquaculture: Historical and current perspectives and future needs and challenges

AbstractImportant operational changes that have gradually been assimilated and new approaches that are developing as part of the movement toward sustainable intensive aquaculture production systems are presented via historical, current, and future perspectives. Improved environmental and economic sustainability based on increased efficiency of production continues to be realized. As a result, aquaculture continues to reduce its carbon footprint through reduced greenhouse gas emissions. Reduced use of freshwater and land resources per unit of production, improved feed management practices as well as increased knowledge of nutrient requirements, effective feed ingredients and additives, domestication of species, and new farming practices are now being applied or evaluated. Successful expansion into culture of marine species, both off and on shore, offers the potential of substantial increases in sustainable intensive aquaculture production combined with integrative efforts to increase efficiency will principally contribute to satisfying the increasing global demand for protein and food security needs.

Trace metals and nutrients in lake sediments in the Province of Bali, Indonesia: a baseline assessment linking potential sources

Bali, Indonesia, receives over 6 million tourists annually, placing demand on resources and infrastructure that competes with expectations of natural beauty. Strongly linked to tourism are highly productive small-scale crafts industries and intensive small-scale agriculture and aquaculture production. Concentrations of nutrients, trace metals and metalloids were determined in soils from various land uses and solid-waste containment areas associated with small-scale industries, along with sediments from Lake Beratan, Lake Tamblingan, Lake Buyan, Lake Batur and the Badung River estuary. Soil associated with laboratory waste storage, and some sediments, exceeded guideline values for mercury or copper. Concentrations of other metals in soils and sediments were consistently below guidelines values, except zinc in solid waste collected from batik production (i.e. fabric-dyeing operations). Waste from batik production contained elevated concentrations of trace metals and nutrients (phosphorus and potassium), but replicates were highly variable. Lake sediments were enriched with phosphorus and nitrogen, likely from agricultural runoff. This important baseline information highlights the value of lake-protection measures in place, identifies risks to environmental health and provides focus for improving the management of contaminant sources to prevent further impacts.

Machine learning analyses of bacterial oligonucleotide frequencies to assess the benthic impact of aquaculture

Aquaculture is a rapidly expanding industry and is now one of the primary sources of all consumed seafood. Intensive aquaculture production is associated with organic enrichment, which occurs as organic material settles onto the seafloor, creating anoxic conditions which disrupt ecological processes. Bacteria are sensitive bioindicators of organic enrichment, and supervised classifiers using features derived from 16s rRNA gene sequences have shown potential to become useful in aquaculture environmental monitoring. Current taxonomy-based approaches, however, are time intensive and built upon emergent features which cannot easily be condensed into a monitoring pipeline. Here, we used a taxonomy-free approach to examine 16s rRNA gene sequences derived from flocculent matter underneath and in proximity to hard-bottom salmon aquaculture sites in Newfoundland, Canada. Tetranucleotide frequencies (k = 4) were tabulated from sample sequences and included as features in a machine learning pipeline using the random forest algorithm to predict 4 levels of benthic disturbance; resulting classifications were compared to those obtained using a published taxonomy-based approach. Our results show that k-mer count features can effectively be used to create highly accurate predictions of benthic disturbance and can resolve intermediate changes in seafloor condition. In addition, we present a robust assessment of model performance which accounts for the effect of randomness in model creation. This work outlines a flexible framework for environmental assessments at aquaculture sites that is highly reproducible and free of taxonomy-assignment bias.

A Definition of Aquaculture Intensity Based on Production Functions—The Aquaculture Production Intensity Scale (APIS)

Aquaculture intensity has been used for years as a means to gauge how much production a site makes using three terms: extensive, semi-intensive and intensive aquaculture production systems. The industry has a relatively coordinated understanding of these terms, but an explicit general definition does not seem to exist. This paper aims to use three kinds of production function groups; the input, treatment and output functions to describe and define the terms extensive, semi-intensive and intensive explicitly. This is done with extensive literature review to find the meaning of the terms. The terms are then mapped onto the three production function groups. The resulting framework accomplishes two things. Firstly, it defines extensive, semi-intensive and intensive aquaculture in terms of production functions. Secondly, it creates an eight level scale, the aquaculture production intensity scale (APIS), that provides three levels of extensive systems, two level of semi-intensive systems and three level of intensive systems. APIS allows mapping of all uses of the terms in current literature to an APIS score, though some results might differ from current usage.