Aquaculture, Fish and Fisheries最新文献

A major expense in the operation of bivalve nurseries is the culture of high-quality live microalgae feeds, and efforts to develop effective alternative feeds have had limited success. Juvenile bivalves are known to be able to absorb dissolved nutrients, but this ability has received minimal attention as a route for supplementary feeding. This study assessed the capacity of juvenile green-lipped mussels (GLMs) (Perna canaliculus) to uptake and assimilate dissolved glucose at five experimental concentrations (i.e. 10 µg mL⁻¹, 100 µg mL⁻¹, 1 mg mL⁻¹, 10 mg mL⁻¹ and 30 mg mL⁻¹) as a supplement to cultured microalgae. Growth and survival of the mussels were measured over 3 weeks. Although all glucose concentrations improved the performance of mussel spat compared to the control, the best performing was a concentration of 1 mg mL⁻¹ of dissolved glucose which enhanced daily spat growth 2.7 times that of the control live microalgal diet without glucose. Survival was high (i.e. >95%) for all treatments except for the highest experimental concentration of glucose, for which a concentration of 30 mg mL⁻¹ resulted in mean mortality of 24%. Mussel spat supplemented with dissolved glucose accumulated up to 30% greater lipid and improved the carbohydrate content per mg g⁻¹ of ash-free dry weight as much as 3.5 times compared to those in the control treatment, indicating that they were in greater nutritional condition. This demonstration that dissolved glucose can be used to fuel growth by GLM spat at concentrations as low as 10 µg mL⁻¹ suggests that other soluble nutrients may also act as a supplemental feed for cultured juvenile molluscs. Dissolved nutrients have the potential to improve the performance of spat in nursery systems while simultaneously reducing the reliance of cultured microalgae as a sole feed input.

To evaluate the success of a stocking program in Fox Lake, Minnesota, adult (≥76 cm total length) Muskellunge were captured with large nearshore trap nets and individually marked with passive integrated transponder tags during the 2011–2013 and 2015–2017 spawning seasons; then, capture–recapture data were analyzed at two different time scales. Despite substantial sampling effort, daily capture histories within a single season only supported closed-population abundance estimates for both sexes in half the years; estimates were imprecise, and there was evidence of trap shyness or violation of the short-term closure assumption in some years. Jolly–Seber models over all years supported relatively precise abundance estimates for both sexes every year, as well as estimates of annual survival, recruitment, and population growth rate. Link–Barker Jolly–Seber models provided estimates of population growth rate λ ≈ 1 indicating that per-capita annual recruitment rates of only about 0.15–0.20 were adequate to maintain the adult population given the high annual apparent survival rates of 0.80 for adult females and 0.89 for adult males. POPAN Jolly–Seber models revealed that about 80 adult females and 90–126 adult males were vulnerable to capture each year in the 385 ha lake, and about 16–18 fish of each sex recruited to the adult population annually. This study illustrates the importance of open-population models with multiple years of data to evaluate the abundance and population dynamics of a low-density, long-lived species.

Fish feed production is fraught with high costs due to the inclusion of expensive fishmeal and animal proteins that can be sourced from aquatic macrophytes. Limited attempts have been made on use of the latter for fish feed production. Further, the quality of feed given to fish is known to affect its growth and reproductive performance. Role of feeds containing duckweed (Lemna minor) at 0%-control feed, 10%, 15%, 20% and 25% inclusion levels on growth and reproductive performance of Oreochromis niloticus of size 18 ± 1 g were evaluated for 12 weeks. The fish were fed twice daily at 10% body weight at 9.00 a.m. and 4.00 p.m. Length–weight measurements were done fortnightly using a measuring board and a weighing balance, respectively. Female mouth-brooding fish were used to evaluate reproductive performance indicators, namely %: fertilization, hatchability and survivability. Data were subjected to one-way analysis of variance followed by post hoc and polynomial orthogonal analysis to identify L. minor diets with significant differences (p < 0.05). Fish fed on a diet containing 10% L. minor inclusion showed significantly better growth performance and feed conversion ratio than those fed on the control diet. All L. minor diets gave good fish condition factors above 1.0. Fish fed on a diet containing 10% L. minor and those fed on the control gave reasonably high survival rates of 85.55% and 83.33%, respectively, whereas those fed on 20% L. minor produced the same growth performance as control. Orthogonal polynomial analysis for the final weights across the L. minor diets – 0%–25% – showed a cubic polynomial model (p = 0.000), whereas final lengths portrayed a linear inverse significant relationship (p < 0.05). Inclusion of L. minor in the diets resulted to slightly better fertilization, hatchability and survivability rates at 10%, 20% and 15%, respectively. In conclusion, inclusion of L. minor from 10% to 20% in fish feeds is recommended for enhancing growth and reproductive performance of O. niloticus.

As a predatory fish that migrates between freshwater and marine environments, the sea trout (Salmo trutta) is important in linking these systems. This study investigated movement patterns of sea trout in a coastal fjord at the Swedish Skagerrak region from August 2018 to January 2019, using acoustic telemetry, while assessing these against environmental variables across different spatial and temporal scales. Six acoustic receivers were deployed in the fjord and a river, which flows into the upper reaches of the fjord, with the aim of detecting 20 sea trout that had been tagged with acoustic transmitters. Sea surface temperature and winds (east–west) affected movement patterns of the sea trout the most, while changes in atmospheric pressure were also important, but to a lesser extent. Sea surface temperature and atmospheric pressure both had a positive relationship with the number of detections, whereas stronger winds from the east (i.e. from land) resulted in more detections than stronger winds from the west (i.e. from the ocean). In addition, interesting diel (day–night) movement patterns were observed for some fish. A significant positive correlation was also discovered between the weight of the fish and the number of detections. This study offers insight in movements of sea trout that use coastal habitats and how environmental conditions can affect movement patterns in a fjord system. To further our understanding of sea trout movement patterns and connectivity, tracking from river, through fjord, out to sea and at a longer time scale with more variation in fish size would be valuable to understand more about the complex movement dynamics of this important species.

Sentiment analysis, a form of data analytics, utilises information from online discussions, reviews, and social media posts to assess consumer sentiments. This study utilised data collected from social media using online listening procedures to assess online sentiments on oysters from January 2019 through December 2022. The analysis utilises machine learning algorithms to extract consumer sentiments, opinions, and demands from online chatter from different online domains. The online sentiments are determined as positive, negative, or neutral based on their word choice, tone, and context. The information provided gives insights into perception, which is valuable information for oyster producers, seafood industry stakeholders, and marketers to identify consumer preferences and formulate appropriate strategies accordingly. The results suggest that while farmed oysters are gaining popularity, there are still some concerns and criticisms around the industry. Positive words associated with mentions of oysters in general include ‘great’, ‘love’, ‘delicious’, ‘enjoyed’, and ‘oyster bar’, while negative words associated with oysters include ‘water’, ‘raw oyster’, ‘bad’, and ‘not eat’. The overall percentage net sentiment associated with all oysters in the United States is positive at 63%. The net sentiment associated with wild oysters is positive, at 51%, and that of farmed oysters is 58%. The oyster industry could invest more in public education, sustainability, and water-cleaning initiatives to improve its image. Utilising social media to monitor and shape public perception can help the industry address concerns and enhance oyster-related sentiments, offering valuable insights for marketing and sales strategies.

Aquaculture, Fish and Fisheries recently celebrated its third anniversary and as part of our ongoing development, we aim to continue to be author-friendly, inclusive and collaborative within the research community and beyond. In our recent editorial to mark the occasion, we set out several ongoing activities at the journal which we hope will continue to improve the author experience (Bailey et al., 2024). As part of this process, we re-evaluated our initial article types, and taking this into account, we will soon be launching a new article type unique to Aquaculture, Fish and Fisheries: Underwater Notes.

Underwater Notes are distinct from our current roster of article types and will provide a platform for atypical/uncharted findings, or questions that may be seen in a new population, or associated with a new species in an unexpected way either relating to diverse themes in aquaculture and fisheries science or fish biology encompassing both marine and freshwater organisms. While we aim to keep an open-minded approach with Underwater Notes, we are not simply looking for validation studies or corroborative reports. They are to be in a shorter format than traditional research articles and include thought-provoking, significant, preliminary studies, experimental procedures, new technologies/systems, or applied activities within laboratories or in the field and opportunistic observations that may not adhere to our more traditional articles, that is hypothesis-driven research.

The idea for this article type stems from collaborative conversations with scientists and editors from multiple disciplines, in which a need was identified for a bridge between full research articles and other streamlined approaches such as short communications, but at the same time convey wider versatility. For instance, ecologists and evolutionary biologists were increasingly looking to reinvigorate the traditional, but neglected over time, discipline of natural history research. In addressing this, Ecology and Evolution developed Nature Notes (Jenkins et al., 2022; Moore et al., 2020), which have seen many new descriptions of species, previously undocumented behaviours and species occurrence reports in areas where they were previously unrecorded. Similar approaches have been taken by journals such as Biotropica (Powers et al. 2021). While this approach draws from other disciplines, we seek to address a need specific to this journal's community, and we feel that Aquaculture, Fish and Fisheries must look to provide its authors with an outlet for their work in the format they wish to present it in. This factors in the broad scope of the journal and applies to studies of all farmed and wild aquatic organisms, encompassing both conservation, production and cultural insights.

We seek, as always, to be author-friendly, and as such we are not setting any limits on words or figur

2024 marks the third anniversary of Aquaculture, Fish and Fisheries, a multidisciplinary journal centering on the biological, socioeconomic, and cultural impacts of aquaculture, fisheries science, and fish biology, covering a broad range of topics addressing both farmed and wild aquatic plants and animals. As part of this journey, AFF has established a record of sound editorial practices that resulted in the journal being listed on the Directory of Open Access Journals and achieving our first impact factor. Here, we look back at the journey that got us this far and provide a perspective moving forward.

In our inaugural editorial ‘Aquaculture, Fish and Fisheries: A New Home for the Blue Revolution’, we highlighted our overarching objective was to provide researchers working within all areas of aquaculture, fisheries science, and fish biology a platform to publish their findings, and by doing this, we sought to build a collaborative relationship with the research community (Becker & Calado, 2021). Our approach was not to place a value on novelty or global relevance but rather to consider scientifically sound research from a wide range of topics covering all areas and populations around the globe, aiming to attract research from underrepresented areas that needed attention the most (Becker & Calado, 2021). Studies of regional scope can be of significant relevance for populations that rely on aquatic ecosystems and their biological resources for their livelihood. Through this process, we have covered a multitude of themes, such as nutrition, sustainability, disease, immunology, conservation, cultural impacts, reproduction, ecology, climate change, pollution, oceanography, management, economics, and policy amongst others. With publications originating from 47 countries and spanning from all the major regions of the globe, we highlight multiple articles from African and Asian countries that have contributed to raising awareness in areas where targeted boosts to sustainable fisheries and aquaculture practices are most needed (FAO, 2024). Moreover, a number of authors based in low-income countries were able to benefit from waiver policies to support article processing charges, making their research available to all those who may benefit from it through open access.

Some of the editorial highlights published thus far have included a review of Nile Tilapia culture in Kenya that explores production technologies and socioeconomic impacts on local livelihoods (Munguti et al., 2022); an investigation into the restoration potential of offshore mussel farming on a degraded seabed habitat in the United Kingdom (Bridger et al., 2022); an assessment of predatory fish diets in invasive fish species in a traditional Hawaiian aquaculture system (Akiona et al., 2022); the evaluation of alternative protein sources in aquaculture in Tanzania (Limbu et al., 20

Marine coastal resources are crucial to Tanzania's socio-economic development and are a lifeline for the livelihoods and incomes of coastal communities. This study provides an overview of the coastal development of mariculture in mainland Tanzania and suggests future development strategies. The review article covers extensive reports available through field interviews, government policy documents, library literature searches and field work carried out by the authors. Despite the immense potential of mariculture to improve food security for localcommunities, its development has been uneven. Specifically only seaweed farming has advanced to commercial-scale production. Other mariculture activities, such as finfish farming (e.g. milkfish, silver pompano), shellfish farming (e.g. prawn, mud crab and half-pearl) and sea cucumber farming, are underdeveloped and confined to small-scale operations. Locally consumed finfish, such as milkfish and pompano, have not attracted investors out of fear that the recovery of investment may not be achieved due to the low prices offered in the market. In this context, the sustainable use of coastal resources through mariculture becomes paramount to alleviating poverty and facilitating controlled migration from rural to urban. This comprehensive review explores the historical evolution and current status of mariculture initiatives in the coastal waters of mainland Tanzania, which presents a crucial aspect of the socio-economic development of the nation. With declining global capture fisheries production and a growing demand for fish protein, Tanzania has strategically embraced mariculture as a viable alternative. The article traced the development of mariculture since the 1970s, highlighting past and current initiatives managed by government agencies, non-government organizations and the private sector. Notable successes, such as seaweed culture, are highlighted along with the challenges that hinder the growth of marine farming activities. The review integrates insights from a comprehensive survey in coastal Tanzania, focusing on mariculture activities and collecting information on people who have stopped such practices, elucidating reasons for quitting. By consolidating experiences from past and present mariculture initiatives, this review provides valuable guidance for decision-making towards promoting sustainable mariculture that supports coastal communities while preserving marine biodiversity.

Saprolegniosis, also called water mould, induces a cotton or wool-like white growth on fish skin. It can kill fish at all stages of life, from eggs to adults. It is caused by oomycetes from the genus Saprolegnia and causes fish mortality and huge financial losses to fish farms and hatcheries. Saprolegnia species are endemic and ubiquitous in all freshwater habitats around the world. The exposing factors for saprolegniosis are still largely unknown, but stressors such as temperature shocks, poor water quality, handling and high fish density have been associated with outbreaks. For decades, malachite green was the most effective treatment against Saprolegnia infection, but it has been banned due to its carcinogenic and toxic effects. This has forced farmers to use alternative disinfection methods against Saprolegnia infection, such as hydrogen peroxide, formalin, Bronopol, NaCl, acetic acid and ozone, although many may have safety concerns or are impractical to use. This has led to the investigation of plant-based compounds with antifungal and antibacterial properties against saprolegniosis. These include extracts of certain herbs, onion, garlic, extracts of the plant Chrysanthemum, essential oils of Eryngium campestre, Mentha piperita, Cuminum cyminum and Thymus linearis, which include a variety of phenolic compounds and fatty acids with antifungal properties. This review combines the current knowledge regarding the predisposing factors to Saprolegnia infections and current methods to prevent and treat them, including those under further research. Thus far, many compounds have been tested and studied, but an effective, suitable and safe compound to treat Saprolegnia infection remains to be found.

The early stages of mussel farming are often inefficient with a large proportion of seed (spat) typically lost early in the production cycle. An effective approach for decreasing such losses is to grow spat to larger sizes in nursery systems prior to seeding. However, for such an approach to be commercially viable, spat must first be separated from their settlement substrates into a single seed format, that is, singulated. This study investigated the efficacy of three commercial protease enzymes (Enzidase PAP, PXT and BAP) and chlorine (NaOCl) in singulating Greenshell mussel (Perna canaliculus) spat from spat-collector ropes. Two distinct experiments involved immersing segments of spat collector rope in seawater solutions with varying concentrations (2.5% or 5%) of each enzyme or chlorine (NaOCl) for different exposure times (10, 30 and 60 min for enzymes; 2 and 5 min for chlorine). After the singulation experiments, all spat were recovered with sieves and reintroduced into the tanks with renewed seawater. After 24 h of rearing, the recovery of alive spat was measured. Results indicate that in Experiment 1, involving spat ∼5 mm in size, the singulation rate was up to 65% for protease enzymes (i.e., in the case of 5% PAP at 30 min) and 61% for chlorine (i.e., at 5% for 2 min). In Experiment 2, involving spat ∼1.5 mm in size, the singulation rate was up to 85% for protease enzymes (i.e., in the case of 5% PXT for 60 min) and 78% for chlorine (i.e., of 2.5% for 5 min). However, these treatments generally resulted in elevated spat mortality, which was exacerbated by increasing concentrations and exposure times, resulting in recovery rates of up to 35% (i.e., for 2.5% PAP for 30 min) in Experiment 1 and 26.0% (i.e., for 5% chlorine for 2 min) in Experiment 2. These findings emphasise the necessity for consideration of chemical concentrations and exposure times to optimise the singulation process while highlighting challenges in achieving high post-singulation survival rates. These insights contribute to ongoing efforts aimed at improving the efficiency and sustainability of mussel farming practices, demonstrating the potential utility of protease enzymes and chlorination in singulating spat from settlement substrate prior to their transfer to nursery systems for further ongrowing.