Sustainable Aquatic Research

Best practices for fish biosecurity, well-being and sustainable aquaculture

Erkan Can — 2023-12-30

Since its inception ~6000 years ago, aquaculture has evolved to enable its survival and growth to become a major contributor of protein of high nutritional value for human consumption, thereby improving food security and reducing poverty. Best practices have been established and updated to reflect developments as they occurred. Currently, best practices reflect all aspects of production from site selection and especially location in terms of proximity to other farms, construction and maintenance of the facilities, management practices, stock selection and acquisition, nutrition, biosecurity, disease control, and processing. Concerns about aquaculture continue to be addressed, and include the effects of pollution, such as from uneaten food and feces on the aquatic environment, and the needs of other users of waterways, such as for recreation/tourism. Best practices have been formalized into accredited standards, such as ISO 9000, and form the basis of Certification by the Global Seafood Alliance. With the intensification of aquaculture, the provision of total food requirements became necessary for the farmed stock. This has led the development of feeds capable of providing all the nutritional needs of the farmed species. Concerns about the sustainability of some feed components, such as protein from trash fish, are ongoing. Disease management has progressed from a curative approach (= therapy) with chemicals/antibiotics to prophylaxis with vaccines, probiotics and plant products. Best practices encompass the most up to date technology, including engineering, life sciences and nanotechnology. For the future, aquaculture is likely to remain at the forefront of ingenuity with the goal of increasing the contribution to human nutrition.

Current Status, Problems, Solution Suggestions and Future Focuses of Aquaculture in Türkiye

Orhan Kılıç — 2023-12-30

Türkiye is a peninsula covered by the Black, Marmara, Aegean and Mediterranean Sea. Also, it has large lakes and rivers. Therefore, its geographical advantage has enabled it to have a significant potential in the aquaculture sector.In Türkiye, a significant amount of production is carried out by both fishing (sea and freshwater fisheries) and aquaculture. Aquaculture, especially in recent years, offers great potential for sustainable fish production and economic gain. Gilt-head bream (Sparus aurata) and European seabass (Dicentrarchus labrax) are popular fish especially in the Mediterranean region (Llorente et al., 2020), and are extensively farmed in Türkiye. Since the 2000s, Türkiye has achieved a great increase in gilt-head bream and seabass farming, and has become one of the world leaders in this field. By 2020, Türkiye's total sea bream and sea bass production reached over 200,000 tonnes (FEAP, 2022). The aquaculture sector contains many ecological, economic and social challenges. To overcome these challenges, all stakeholders should meet and discuss regularly. The views and suggestions of various stakeholders, such as local communities, fishermen, growers, researchers and government officials, are vital for the future of the sector. In this context, the impact of some sectors that are indirectly related to the aquaculture sector may also make significant contributions to the process.

Freshwater Snails (Mollusca, Gastropoda) of the Kızılırmak Delta (Samsun, Türkiye)

Şaban Kabak — 2023-12-30

The Kızılırmak Delta was declared as a Ramsar Site because of its location on the birds migration routes and high exposure to anthropogenic pressures on the delta. There are recent comprehensive studies conducted to determine the trophic levels of the lakes in the delta, together with faunal studies to assess its biodiversity. However, there are limited preliminary studies on the freshwater snail fauna. In this study, we determined 15 species, including two from Neritimorpha, three from Caenogastropoda, and ten from Heterobranchia, at 25 stations in the research area. Gyraulus piscinarum (N: 462) was abundant at most stations, while Acroloxus lacustris (N: 1) was determined at one station. We recorded Armiger crista, G. piscinarum, and A.lacustris for the first time from the study area and in the Black Sea Region. Theodoxus major and Ecrobia maritima, which arePonto-Caspian species, are classified as "Data Deficient" (DD)according to the International Union for the Conservation of Nature(IUCN) Red List of Threatened Species Data (2022). In addition, the populations of Valvata macrostoma (LC-Decreasing) aredeclining, and there is no information about the population status of Ecrobia ventrosa (LC), Planorbis planorbis (LC), and G.piscinarum (LC). Detailed fauna studies should be completed in our country urgently to determine the factors that threaten freshwater snails and to take the necessary protective measures. This is the first comprehensive study to determine the freshwater snail fauna of the Kızılırmak Delta to close the malacofaunal gap in the region.

Significant enhancement of survival, intestinal digestive enzymes, vitellogenin content, immune response, and antioxidant defense system of Artemia urmiana fed with garlic (Allium sativum) powder

Hamidreza Ahmadniaye Motlagh — 2023-12-30

Garlic is widely known for its antimicrobial, antioxidant, and immunostimulant properties. The present study aimed to assess the effects of garlic (Allium sativum) powder on the survival, growth, immunological response, antioxidant activities, and reproductive performance of Artemia urmiana. Three diets containing 5%, 10%, and 20% garlic powder feed, and a control diet (C) without garlic were used through a completely randomized design (treatments with triplicates). Twelve 60-L plastic tanks with a density of 20 nauplii per milliliter were used. Artemia were fed with Baker's yeast (1.25 mg yeast per one thousand nauplii) during the 30-day experiment. The study showed that 10% garlic treatment resulted in the highest survival rate (P < 0.05). The growth factor (dry weight) remained unchanged throughout the experiment. The activities of digestive enzymes (protease, amylase, lipase, and alkaline phosphatase), immune response (lysozyme and phenoloxidase activities), and antioxidants (superoxide dismutase and catalase) considerably increased in the treated groups (P < 0.05). Supplementation of A. urmiana diet with varying concentrations of garlic powder significantly increased the level of vitellogenin. However, no significant difference was found in nauplii and cyst production across all the groups. The study suggested that garlic, especially at 10% added feed, might effectively enhance the survival rate, immune response, digestive enzyme activity, antioxidant status, and vitellogenin content in A. urmiana.

Characterization of benthic macrofauna in Iloilo river

Patrick Andre Fernandez — 2023-12-30

Iloilo River is a vital area for fishing, tourism, and various economic activities. It has experienced rapid changes with developments along the area that may influence its ecological processes.This study is an assessment of the abundance and diversity of benthic macrofauna in Iloilo River through the identification of the major taxonomic groups found along the area. Bivalvia dominated all the sampling stations with a count of 115-4935 individuals contributing to 71.70% of all the identified individuals. Overall diversity (H’) was poor with a range of 0.45-1.12. The taxon richness (S) indicated that there were only 3-4 taxa present at each sampling station. Taxon evenness (J’) was also relatively low with a range of 0.32-0.84. The biological indices suggest poor taxon diversity and low population uniformity. Although redox potential showed that the sediment habitat of these macrofauna are under oxic conditions, low D.O. may suggest influence on the distribution of the benthos.

Microbiological study of Sciaenid species collected from coastal waters of Niger Delta, Nigeria

Olaniyi Olopade — 2023-12-30

This study was carried out to determine and compare the microbial load in Sciaenid species (Pseudotholithus. typus, P. senegalensis and P. elongtatus) collected from the coastal waters in Rivers State, Nigeria. Fish samples were purchased from the local fishermen and transported in ice packs to the Microbiology Laboratory. The mean bacterial counts on the skin of the three fish species using Nutrient Agar for general purpose showed that P. typus had the highest loads (2.560 x 10³ CFU g^-1)followed by P. elongtatus with 1.360 x 10³ CFU g^-1 and P. senegalensis (8.00 x 10² CFU g^-1) respectively. Mannitol Salt Agar (MSA) used for the isolation and identification of Staphylococcus aureus revealed that P. senegalensis had 3.0 X 10^-1 CFU g-1, and Staphylococcus aureus was detected on the skin of P. typus and P. elongtatus. On SSA agar, the bacterial counts for the species were highest in P. senegalensis (6.326 x 10² CFU g^-1) followed by P. elongtatus and P. typus with mean values of 5.90 x 10²CFU g^-1 and 5.350 x 10²CFU g-¹respectively. Bacterial counts on TCBS were highest in P. senegalensis with a mean value of 3.15 x 10²10¹ CFU g^-1_, P. typus had 2.925 x 10²CFU g^-1and P. elongtatus had 2.26 x 10² CFU g^-1. Fungi isolated on TCBS were low in all three fish species, with the highest mean value of 1.60 x 10¹ CFU g^-1 recorded on P. typus followed by P. elongtatus (1.50 x 10¹ CFU g^-1) and P. senegalensis (1.25 x 10¹ CFU g^-1). The prevalent bacteria in this study were Shigella species, Aeromonas species, Pseudomonas flourescens, Vibrio species, Staphylococcus species, Salmonella species, Bacillus species, and Micrococcus species. While fungal counts found on the skin of the three fish species include Aspergillus flavus, Aspergillus niger, and Rhizopus stolonifera, Rhizopus stolonifera. The organisms isolated in this study are of public health significance, and their presence suggests that foodborne illness could arise if these fish are consumed in an undercooked state.