Marine aquaculture is growing quickly and has substantial effects on people and the environment. Existing research has demonstrated that marine aquaculture can contribute to ecosystem service ...provisioning that extends beyond production of a resource; however, the extent and significance of these goods and services are not well understood. Here we review existing knowledge of ecosystem service provision by marine aquaculture by systematically examining 129 peer reviewed papers that describe the provision of nine distinct ecosystem services by operational or experimental marine aquaculture farms. We quantify service provision and classify services by type and by farm characteristics. We show that while certain services, such as nutrient absorption by kelp aquaculture, are well understood and have been documented across multiple species, scales and environments, the evidence for other services, such as the cultural service of tourism, is currently minimal. Importantly, we identify ecosystem services associated with a diversity of farm types (including fish, bivalve, algae and polyculture farms) but find that certain services were most often delivered by specific farm types (e.g. habitat services were most often associated with fish farms). Incorporating acknowledgement of ecosystem services into farm design and planning has the potential to improve environmental performance and sustainable management of aquaculture. However, outstanding questions, including how spatial expansion of marine aquaculture will affect the provisioning of these services, are important challenges facing sustainable development.
In intensive farming systems, fish are held at high densities, which may increase stress, leading to susceptibility to diseases that result in economic losses. Therefore, effective feeding practices ...incorporating health‐promoting compounds such as proteins, hydrolysates and bioactive peptides that can stimulate the defence mechanisms of fish and achieve better growth are some of the priorities for sustainable aquaculture development. Globally, the fish processing industries generate and discard a large volume of waste every year, estimated at up to 60% of the harvested biomass. This waste can be converted to value‐added products such as fish protein hydrolysate (FPH) with the addition of various proteolytic enzymes. FPH from fish processing waste including skin, heads, muscle, viscera, liver and bones is a good source of protein, amino acids, peptides and antioxidants and has been found to possess desirable functional and bioactive peptides. A moderate inclusion of FPH in aquafeeds has the potential to improve growth, feed utilization, immune functions and disease resistance of fish. Production of FPH, targeted to more precise molecular weight ranges, has superior functionalities that are in high demand. With interest in FPH as an aquafeed supplement, this review aimed to summarize the source, production processes and functional properties of FPH and the reported impact of FPH in aquafeed supplement on fish growth, survival, feed utilization, immune response and disease resistance. Possible limitations of using FPH and future research potential as an opportunity for the use of processing fish waste are also discussed.
Mariculture is an important part of aquaculture, and it is important to address global food security and nutrition issues. However, seawater environmental conditions are complex and variable, which ...causes large uncertainties in the remote sensing spectral features. At the same time, mariculture types are distinct because of the different types of aquaculture (cage aquaculture and raft aquaculture). These factors bring great challenges for mariculture extraction and mapping using remote sensing. In order to solve these problems, an optical remote sensing aquaculture index named the marine aquaculture index (MAI) is proposed. Based on this spectral index, using time series Sentinel-1 and Sentinel-2 satellite data, a random forest classification scheme is proposed for mapping mariculture by combining spectral, textural, geometric, and synthetic aperture radar (SAR) backscattering. The results revealed that (1) MAI can emphasize the difference between mariculture and seawater; (2) the overall accuracy of mariculture in the Bohai Rim is 94.10%, and the kappa coefficient is 0.91; and (3) the area of cage aquaculture and raft aquaculture in the Bohai Rim is 16.89 km2 and 1206.71 km2, respectively. This study details an effective method for carrying out mariculture monitoring and ensuring the sustainable development of aquaculture.
Abstract
Climate change is an inevitable event that obstructs the output of aquaculture farms and culture-based fisheries in open waters. It poses a serious threat to global food security, altering ...biodiversity, ecosystems, and global fish output by displacing fish stocks from their natural habitats. When compared to freshwater aquaculture, marine/coastal aquaculture is more affected. To combat the effects of climate change, several mitigation methods and adaptations are being implemented, emphasizing future demands of affordable protein. Selective breeding, species diversification, and aquaculture systems like integrated multi-trophic aquaculture, aquaponics, and recirculating aquaculture system are some of the most widely accepted and adapted solutions. Further research on intervention in seed and feed in terms of quality improvement, bioresource utilization, and technological and genetic improvement is required. Climate change policies from the government are also essential. The present study differs from previous reviews by portraying the various abiotic stress factors contributing to the drastic climate change, encompassing adaptation strategies followed in distinct aquaculture sources such as freshwater, inland saline water, brackish water, coastal waters, and culture-based capture fisheries with its future implications.
Global increase in aquaculture production has created a need to reduce its environmental impacts. Nutrients could be recycled especially at land-based recirculating aquaculture systems (RAS) by ...cultivating green microalgae in aquaculture effluent. However, microalgae are difficult to harvest. As a multi-trophic solution, mussels could be used in harvesting microalgae. We tested three European freshwater mussels (duck mussel
Anodonta anatina
, swan mussel
A. cygnea
, and swollen river mussel
Unio tumidus
) for filtering two common green microalgae (
Monoraphidium griffithii
and
Selenastrum
sp.) grown in RAS effluent. Mussels decreased microalgal concentrations in the tanks 42–83% over three consecutive trials. Algal concentrations at the end of each trial were lowest for both microalgae in tanks containing
Anodonta
mussels. Clearance rates were higher for
Anodonta
mussels than for
U. tumidus
. Mussels biodeposited more microalgae to tank bottoms when
M. griffithii
was filtered. Ammonium concentration decreased or did not change in tanks with
M. griffithii
, but increased in tanks containing
Selenastrum
sp. These results suggest that of the tested species
Anodonta
mussels and
M. griffithii
show best potential for RAS effluent bioremediation application. We conclude that a co-culture of microalgae and unionid mussels could be used for recycling nutrients in aquaculture.
Biofloc technology (BFT) has gained increased interest as a potential low-cost and environmentally friendly method for sustainable aquaculture development. However, the addition of external organic ...carbon source and the increased aeration needed to promote biofloc formation could be a limitation of this technology. The integration of microalgae on the BFT has the potential to improve the overall efficiency of the method, since microalgae can photosynthetically assimilate nitrogen (ammonia, nitrate, and nitrite) without the requirement of external organic carbon addition. In this work, BFT was supplemented with microalgae
Nannochloris
sp. isolated and adapted in BFT, while four different C/N ratios (0:1, 5:1, 10:1, and 15:1) were applied in artificial aquaculture wastewater to investigate the nitrogen removal efficiency under reduced external organic carbon addition and to assess the nutritional value of the produced biomass. The present study demonstrated that microalgal integration into a biofloc system led to an efficient ammonia removal and repression of nitrite formation at a lower C/N ratio of 5:1 compared to optimum 15:1 of the series consisting of biofloc only. At the optimum levels of C/N, protein content was not changed (around 37%); however, the incorporation of microalgae into the biofloc resulted in a significant decrease of protein digestibility. Lipid content was also decreased (from approx. 16 to 11%) in the series with incorporated microalgae with less unsaturated fatty acids composition. Microbial diversity was altered in the different series examined, while bacterial and eukaryotic communities participating in the nitrogen cycle and degradation of complex organic compounds were discussed.
Biofouling in marine aquaculture is a specific problem where both the target culture species and/or infrastructure are exposed to a diverse array of fouling organisms, with significant production ...impacts. In shellfish aquaculture the key impact is the direct fouling of stock causing physical damage, mechanical interference, biological competition and environmental modification, while infrastructure is also impacted. In contrast, the key impact in finfish aquaculture is the fouling of infrastructure which restricts water exchange, increases disease risk and causes deformation of cages and structures. Consequently, the economic costs associated with biofouling control are substantial. Conservative estimates are consistently between 5-10% of production costs (equivalent to US$ 1.5 to 3 billion yr
−1
), illustrating the need for effective mitigation methods and technologies. The control of biofouling in aquaculture is achieved through the avoidance of natural recruitment, physical removal and the use of antifoulants. However, the continued rise and expansion of the aquaculture industry and the increasingly stringent legislation for biocides in food production necessitates the development of innovative antifouling strategies. These must meet environmental, societal, and economic benchmarks while effectively preventing the settlement and growth of resilient multi-species consortia of biofouling organisms.
This study reviews the development and conventional qualitative analysis of aquaculture in Africa, specifically by reviewing the aquaculture sector of key players (Egypt, Nigeria and Uganda) as a ...reference for South Africa; an aspiring key aquaculture player in Africa based on the launch of Operation Phakisa-South African version of the blue economy initiative. The key players were identified based on current annual production output and critical success factors, thus used as a benchmark for South Africa. Qualitative factors reviewed are critical success factors of the aquaculture sector of the selected countries that are widely germane to aquaculture development. These factors include production outputs (tons) and value ($); cultured species; prevalent aquaculture production systems; types of aquaculture, i.e., freshwater and mariculture; aquaculture development challenges related to fish seed, fish feed, land and water availability; aquaculture market and trade and provision of enabling environment through policies and frameworks. These factors were qualitatively reviewed and analyzed in ranking the aquaculture operations of the key players and South Africa to elucidate the critical success factors and challenges.
Diseases are one of the most critical limiting factors in aquaculture. Recirculating aquaculture systems (RAS) are one of the most functionally viable sustainable aquaculture production systems ...adopted world over. In the event of any eventuality caused by bacterial pathogens, antibiotics or other antibacterial agents cannot be applied due to the vulnerability of biological filters which form an integral part of the RAS. Because of this, newer drugs are required for the effective control of diseases in RAS which would not interfere with the activity of nitrifying bacteria used in the biological filters. The antagonistic activity of pyocyanin, a bioactive compound produced by
Pseudomonas aeruginosa
, against vibrios is well established. The purpose of this study was to prove the effectiveness of pyocyanin as an aquaculture drug for application in RAS by employing a pilot-scale shrimp culture under RAS. It was noted that at the concentration of 5 mg L
−1
, pyocyanin could significantly bring down the population of
Vibrio
spp. in RAS without affecting noticeably the other natural heterotrophic bacteria. Also, pyocyanin at this concentration did not inhibit the activity of nitrifying bacterial consortia used in the SBSBR (stringed bed suspended bioreactor) of RAS. The reared shrimp (
Penaeus monodon
) showed 100% survival after the application of pyocyanin, besides exhibiting normal health signs. Pyocyanin was non-toxic to the shrimp hybrid cell line (
Pm
LyO-
Sf
9) at the concentration required for its application in disease management (IC
50
= 419.26 mg L
−1
). The present study has demonstrated that pyocyanin is effective as an environment-friendly and safe aquaculture drug for the application in RAS-based shrimp culture to control
Vibrio
spp. without impeding nitrification established through the deployment of nitrifying bioreactors.
PDF
