Sustainable Aquatic Research

Dietary available phosphorus restriction and skeletal integrity in stomachless fish Gnathopogon caerulescens and Carassius auratus: the effects of ferric chloride supplementation

Shozo Sugiura — Sat, 31 Aug 2024 00:00:00 +0300

Phosphorus is abundant in most feed ingredients and classified into two forms: available phosphorus and unavailable phosphorus. Available phosphorus is absorbed in the intestines of fish and used for various physiological needs. Any excess available phosphorus is excreted in urine, which is water-soluble and directly stimulates the growth of algae and macrophytes in surrounding water bodies. Therefore, minimizing the available phosphorus content in feeds to match the exact requirement level of fish is necessary to reduce the environmental impacts of aquaculture and promote its sustainable development. This study aimed to develop a technology to minimize the available phosphorus content in aquaculture feeds using ferric chloride as a phosphorus-binder. In a soybean meal-based diet devoid of inorganic phosphorus, the dietary addition of ferric chloride had no measurable effect on bone ash content or bone formation in experimental fish: Gnathopogon caerulescens and Carassius auratus, both stomachless fish belonging to the cyprinid family. However, in a purified diet containing a normal concentration of inorganic phosphorus, the dietary addition of ferric chloride significantly decreased the bone ash content of the fish. Similarly, in a commercial diet containing inorganic phosphorus, dietary ferric chloride decreased the bone ash content of the fish. In conclusion, for diets containing soluble inorganic phosphorus, supplementing with ferric chloride can reduce the available phosphorus content, thereby decreasing the phosphorus burden on surrounding water bodies. However, when reducing the dietary available phosphorus content, it is advisable to occasionally monitor the bone ash content or check for bone deformities in cultured fish to prevent clinical deficiencies.

Empowering Hilsa Heroines: Unveiling Gender, Socioeconomic Dynamics, and Environmental Influence in Bangladesh's Fisherwoman Community

ABM Hossain, Ayesha Siddiqua — Sat, 31 Aug 2024 00:00:00 +0300

This study provides a detailed insight into the socioeconomic challenges faced by fisherwomen households in the Shugondha riverbank Hilsa fishing community of Bangladesh. Despite their active involvement in hilsa fishery, these households grapple with various economic and social hurdles. The research methodology, employing a mix of questionnaire interviews, focus group discussions, cross-check interviews, and secondary data collection, ensures a comprehensive understanding of the subject. Conducted over 12 months in Chandkathi Jelepara, Jhalokathi Sadar Upazila, Jhalokathi district, the analysis included 42 households with 100 active fishers, sustaining 240 people. They are predominantly Hindu and illiterate (52%), socio economically poor households (57%), and lacking land ownership (90.5%) and basic amenities. Food shortages during fishing bans were managed through reduced meals and cheaper goods. Limited control over household income (2%) and low awareness of rights (95%) were observed among fisherwomen. Income generation efforts were hindered by resource scarcity and lack of skills. However, 10% recognized the need for diversifying income sources and active participation in community initiatives. Vulnerability was high, emphasizing the need for support from government, NGOs, and other organizations to improve livelihoods, particularly through alternative income options.

Finfish harvest trends in the Chalakudy River within the Western Ghats biodiversity hotspot in the Southwest of India

Renjithkumar Chelapurath Radhakrishnan, Kuttanelloor Roshni — Sat, 31 Aug 2024 00:00:00 +0300

Quantifying the fish harvest from a riverine aquatic ecosystem is a major pre-requisite for fisheries management. In this direction, the present study estimated the fin fish harvest of Chalakudy River, flowing through the Western Ghat biodiversity hotspot in the Southwest coast of India from June 2019 to May 2020 covering major fish landing centres. The fishery yield from the Chalakudy River was estimated at 68.53 tonnes, comprising 68 fin fish species under 37 families and 57 genera. Family Cyprinidae dominated with 19 species, followed by Cichlidae (5 species), Channidae, and Bagridae (three species each). Cyprinids (48.42%), cichlids (14.56%), catfishes (12.66%), and murrels (8.79%) constituted the major fish groups that contributed to the fishery. The landings were represented by one critically endangered (CR) (Hypselobarbus thomassi), two endangered (EN) (Osteochilichthys longidorsalis, and Tor malabaricus) and five vulnerable (VU) (H. kolus, Hyporhamphus xanthopterus, Wallago attu, Channa diplogramma and Horabagrus brachysoma) fish species. The dominant fish species in the fishery were Cyprinus carpio (6.36 t), H. kolus (5.23 t), Barbodes carnaticus (4.85 t), Etroplus suratensis (4.07 t), and T, khudree (3.46 t). The exploited fishery comprised 15 alien species, encompassing 12 exotic species and three transplanted species from Northeast India. Gill nets (91.77%) was the most dominant gear used in the riverine fishery followed by seine nets (4.99%), hooks and lines (2.02%), cast nets (0.98%) and fish traps (0.23%). Our research reveals that the fish population in the Chalakudy river faces intense exploitation, with substantial catches of exotic fish species posing challenges to both the sustainability of the fishery and the survival of native fish. This highlights the urgency of conserving the river's unique and threatened biodiversity.

Exploration of Nitzschia from the Coastal Water of Suak Ribee, West Aceh Regency, Indonesia

Sat, 31 Aug 2024 00:00:00 +0300

Indonesia, a critical biodiversity hotspot, harbors diverse ecosystems. Diatoms, siliceous microalgae, are crucial in primary production and oxygen generation globally. With over 100,000 identified species, diatoms exhibit vast morphological diversity influenced by their unique cell division and life cycle. They are significant food sources for zooplankton, contributing to silica sequestration in aquatic environments and vital biological indicators of water quality, responding to environmental changes. The genus Nitzschia, a diverse group comprising nearly 3,000 names classified within the Sigmoideae group, has been found valuable in aquaculture due to its fatty acid content. This study isolates and identifies Nitzschia, a diatom from Suak Ribee Beach, West Aceh Regency, Indonesia, utilizing morphological characteristics for species identification. The research aims to contribute to understanding diatom diversity and ecological roles in this coastal environment.

Fish diseases and fish health investment needs for aquaculture sector in Kenya

Sat, 31 Aug 2024 00:00:00 +0300

Aquaculture plays an important role in provision of food, livelihood and source of income in Kenya. There is a rapid shift from extensive methods to semi-intensive and intensive culture methods with the potential of producing higher output. However, intensification in aquaculture comes with risks of diseases. In recent years, there has been an increase of emerging and re-emerging diseases in aquaculture. Increased occurrence of diseases in aquaculture production systems leads to reduced profits, affecting the social and economic sustainability of aquaculture. To mitigate the negative impact of fish diseases in aquaculture, rapid discovery, characterization, and diagnosis of causative agents and risk factors are crucial for the development of effective control measures. Furthermore, investment in skilled personnel/researchers, development of relevant prophylactics, biopesticides and chemo-therapeutants, well-equipped and dedicated laboratories, institutional capacity governing aquatic animal health issues, routine surveillance, quarantine facilities and improving the linkages between various stakeholders in the aquatic animal health issues nationally and beyond will be critical in improving fish health and disease control in the aquaculture sector in Kenya.

The Publication Game in the Aquatic Sciences– an Editor in Chief’s Perspective

Brian Austin, Erkan Can — Sat, 31 Aug 2024 00:00:00 +0300

The editorial in the last issue was evocative and thought provoking (Steinberg, 2024). Consequently, it is appropriate to include an Editor in Chief’s perspective on the manuscripts that are received and considered for publication. It is realized that the publication process is stressful for the authors, but success is euphoric. Authors strive to publish in top class refereed international journals with success contributing to career security and advancement. The utopian desire of editors is to publish well-written manuscripts describing excellent work that will be well received by the readership and contribute to the all-important journal metrics. In short, we live in a period dominated by impact factors, and the number of citations, article downloads and reads. There may be contractual obligations with the publisher regarding the number of articles to be accepted and published within a defined period. In short, there is pressure on editors and authors. So, what is the reality of the situation. To dispel one myth, not all submissions lead to publications. It is not unusual that only a small minority of the submissions are actually published.

The developments in the publication process have been met with a veritable explosion in the number of manuscripts submitted to journals posing tremendous pressure on the editors to deal with them in a timely manner for the benefit of authors and journals alike. Many submissions will be culled during the initial quality checks. The rest need to be assessed in terms of the content. This is the principle role of the editors and referees. However, for the system to work effectively, referees need to provide fair, impartial comment. We do not need false praise from “friends” or antagonistic comments from competitors. The reports guide the editor to make informed judgements. Could the process by improved? Well, we are certainly open to suggestions! There are clearly interesting times ahead.