Aquaculture is the world's fastest‐growing food‐producing sector, making it a significant contributor to food and nutrition security for the globally growing human population. Nevertheless, its long‐term growth is limited by the effects of climate change. Aquaculture in Sub‐Saharan Africa (SSA), which is dominated by small‐scale fish farming, is increasingly threatened by climate change, which has a substantial influence on its productivity and scalability. In this context, the present research looks at the socio‐economic consequences of climate change on small‐scale fish producers in SSA, as well as potential adaptation techniques to the effects of climate change. A clear understanding of these socio‐economic repercussions of climate change is critical for developing effective strategies to reduce future impacts and safeguard aquaculture‐based livelihoods. Furthermore, understanding the socio‐economic consequences of climate change on communities dependent on aquaculture is important for advising policymakers and decision‐makers on formulating and implementing policies that sustain aquaculture production amidst the climate change crisis. This article suggests various adaptation strategies to increase resilience to climate change, including diversification of livelihoods and species, use and incorporation of local and indigenous knowledge, shifting to aquaculture species less vulnerable to changing climatic conditions, capacity building through aquaculture insurance schemes, continued fish supply from capture fisheries, and consolidation of equity and human rights concerns. These adaptive methods, when combined, have the potential to enhance outcomes for populations who are more susceptible owing to their unstable socio‐economic conditions.
Bycatch, the unintentional capture of non-target species, poses a significant challenge in fisheries management worldwide. Underutilized bycatch species often lack biological information, hindering the assessment of their stock status and the implementation of appropriate management strategies. This study investigated the length–weight relations (LWRs) of 9 of 14 underutilized bycatch fish species collected from set-net fisheries in Nishiki, Mie Prefecture, Japan, during the 2018–2020 fishing seasons. The following fish species were studied: Hyperoglyphe japonica (Döderlein, 1884); Labracoglossa argenteiventris Peters, 1866; Macroramphosus sagifue Jordan et Starks, 1902; Microcanthus strigatus (Cuvier, 1831); Ostorhinchus semilineatus (Temminck et Schlegel, 1843); Parapriacanthus ransonneti Steindachner, 1870; Rexea prometheoides (Bleeker, 1856); Siganus fuscescens (Houttuyn, 1782); Upeneus japonicus (Houttuyn, 1782). A total of 251 fishing operations were conducted, and the collected fish specimens were measured for length (fork length) and wet weight. Simple regression analysis was performed on the logarithm of length and weight data to estimate the LWR parameters (a, b, and R2) for each species. The estimated values of the relative growth coefficient (b) ranged from 2.862 to 3.311, and the coefficients of determination (R2) were above 0.8 for all species, indicating robust LWR estimations. Notably, five species were not previously listed or credibly described in FishBase, and four were new records for the Japanese coast. This study provides new biological information on LWRs for underutilized bycatch fish species, contributing to our understanding of their population dynamics and supporting future management efforts for sustainable fisheries and biodiversity conservation.
Hoang Do‐Huu, Sang Minh Huynh, Hue Thi Nguyet Nguyen
et al.
Abstract The efficacy of dietary β‐glucan supplementation in golden trevally (Gnathanodon speciosus) was evaluated. The fish were fed five different diets supplemented with 0%, 0.05%, 0.10%, 0.20%, and 0.40% β‐glucan for 56 days. After 56 days of culture, survival was the highest when the fish were fed a 0.10% β‐glucan diet. Growth rates were higher in fish fed diets supplemented with all β‐glucan levels. Lymphocytes increased when the fish were fed a diet supplemented with 0.05% β‐glucan, and thrombocytes increased when the fish were fed 0.2% and 0.4% β‐glucan‐supplemented diets. The total aerobic bacteria count in the gut of golden trevally was higher (p < 0.05) and the total Vibrio counts in the gut of golden trevally were lower (p < 0.05) when the fish were fed any level of β‐glucan. Flesh protein content was higher and flesh lipid content was lower when fish were fed β‐glucan‐supplemented diets at levels greater than 0.1%. When challenged with Streptococcus iniae, fish fed diets containing 0.10% or 0.20% β‐glucan exhibited the highest survival rates. The current results suggest that supplementation with 0.05 to 0.2% β‐glucan in the diet would be beneficial for the culture of the golden trevally.
This trial was conducted to assess the effects of different levels of dietary fish oil on growth performance, hepatic health, nonspecific immune responses, and intestinal microbial community of Amur grayling (Thymallus grubii). Five isonitrogenous diets containing 60 (6FO), 90 (9FO), 120 (12FO), 150 (15FO), and 180 g/kg (18FO) fish oil were fed to triplicate groups of 60 fish per tank for 8 weeks, respectively. The results revealed that specific growth rate (SGR) and weight gain (WG) of fish in the 15FO group were significantly greater than those in the 6FO group (p<0.05). Somatic indices and whole-body lipid levels were positively correlated with increases in dietary fish oil levels. Trypsin and lipase activities in 15FO and 18FO groups were significantly higher than those in the 6FO and 9FO groups (p<0.05). The activities of intestinal catalase (CAT) and liver superoxide dismutase (SOD), CAT, lysozyme (LZM), alkaline phosphatase (AKP), and acid phosphatase (ACP) improved significantly as the dietary lipid content increased to 185.3 g/kg and decreased thereafter (p<0.05). The lipid metabolism-related genes peroxisome proliferator-activated receptor gamma (PPARγ) and carnitine palmitoyltransferase 1A (CPT1A) were significantly downregulated and upregulated (p<0.05), respectively, in the 15FO group. Immune-related genes in the liver and intestine, such as interleukin (IL-8), were significantly upregulated in the 15FO group (p<0.05). The liver sections from 18FO group presented more numerous and larger lipid vacuoles. Both low- (6FO) and high-lipid (18FO) diets reduced the relative abundance of intestinal Lactococcus. The relative abundances of intestinal Staphylococcus and Bacillus (mainly Bacillus anthracis) increased in the low-lipid diet group and that of Pedobacter increased in the high-lipid diet group. Second-order polynomial analysis of WG and the feed conversion ratio (FCR) for varying levels of dietary lipid revealed that a range of 194.76–198.90 g/kg dietary lipid was optimal for the growth and health of Amur grayling.
Arie Antasari Kushadiwijayanto, Shifa Helena, Warsidah
et al.
Kabung Island is an island located in Bengkayang Regency, West Kalimantan, Indonesia. The characteristics of these waters are sandy, muddy and muddy sand. This type of water is compatible with the life of Gastropods and Bivalves. Both of them play an important role in an ecosystem because of their ability as a filter feeder that filters dissolved substances in the water, for a source of food for their survival. The abundance and diversity of molluscs are highly dependent on the conditions of the aquatic environment, such as substrate type, pH, turbidity, temperature, salinity and dissolved oxygen, availability of food, pollutants, predators and competitors. This study was aims to assess the diversity and abundance of molluscs on the Kabung island. The results on this research show that the highest diversity index is 1.94 which means that it is in moderate condition. The evenness index and dominance index values found to show a value of 0.88 which means high evenness so that a dominance value of 0.45 means that there are no molluscs that dominate on the Kabung island.
Keywords: Abundance, Bivalves, Diversity, Gastropods, Mollusca.
AbstractAtlantic salmon,SalmosalarL., stocks worldwide have dwindled, and stricter recreational fishing regulations have been implemented. This study estimates the recreational value of salmon fishing under different regulatory schemes and identifies factors explaining changes in net economic value of sport fishing. A Contingent Valuation mail survey in the Verdal River, Norway, asked anglers their willingness‐to‐pay for increased fishing expenditures or willingness‐to‐accept compensation in reduced fishing expenditures, to estimate recreational value. The average annual recreational value per angler decreased under stricter regulations from about €420 (in 2007–2009) to €280 (2010–2012) to €180 for the future scenario (2013–2015). Although an overall net decline in recreational value was found with stricter regulations, anglers have heterogeneous preferences. Anglers with non‐catch motives or high place attachment have higher recreational value with stricter regulations than others. If stricter regulations remain over time, younger, less consumptive‐oriented anglers would probably dominate the fishery.
Korea’s fisheries science research began in 1921 at the Fisheries Experiment Station established during the Japanese colonial periods. Japan launched the station to plunder Korea’s fisheries resources (NFRDI, 2001). After the liberation, the nation had to start rebuilding the country based on the poor infrastructure with heart-breaking history. But since then, nation’s only fisheries research institute, the National Institute of Fisheries Science (NIFS), has been established and has promoted the development of fisheries technology and industry, Korea’s fisheries industry has been on par with advanced countries. As we look back over the past century of the Korean fisheries science research, the initial stage of research started with basic oceanographic observations and fishery surveys in the 1920’s. From 1930’s up until the end of the Japanese colonial periods, Japan investigated fisheries resources on the coasts of Korea for the purpose of procuring war supplies. From the late 1940’s to the 1950’s, after the liberation, the dissemination of agar manufacturing technology has promoted the Korean export industry, accounting for 20 percent of the nation’s total exports (NIFS, 2019). In the 1960’s, the emergence of Korean distant-water fisheries such as tuna fishing (MSIT, 2015) and the development and dissemination of shellfish and seaweed farming technologies, including oyster, clams, laver, and sea mustard, increased the seafood production and export, building a solid basis for the Korean economy (Bae, 1985). Fisheries science research has further advanced since the 1970’s, where the development of hygiene management and processing technologies of fisheries products have accelerate the shellfish export, and researches on stow net and anchovy tow net fisheries enabled a significant cost reduction (NIFS, 2019). Since the 1980’s, starting with the development of flounder farming technology, hard efforts have been made to develop aquaculture technologies for a variety of aquatic organisms, such as olive flounder and abalone (Park & Kim, 2013), according to the government’s fish farming development policy. In particular, in the 1990’s, our research capability has expanded to address marine environmental issues, developing monitoring technologies and preventive measures in response to a mass occurrence of harmful aquatic organisms such as red algae. In the 2000’s, NIFS has led the development of high-tech aquaculture technologies by developing
In mammals, the transcription factors paired box-5 (Pax-5) and B-lymphocyte-induced maturation protein-1 (Blimp-1) maintain strict command of B-cell differentiation from hematopoietic stem cells to plasma cells. Here, we identified the Pax-5 and Blimp-1 genes and their predicted proteins in the orange-spotted grouper (Epinephelus coioides). Grouper Pax-5 was predicted to contain a paired box domain and a positive regulator domain, and five zinc fingers were predicted in grouper Blimp-1. Sequence alignment revealed that grouper Pax-5 and Blimp-1 shared a high sequence identity with that of other teleosts, particularly in the functional motifs. Tissue distribution analysis demonstrated that all tissues studied from healthy grouper expressed Pax-5 and Blimp-1. Pax-5 had the highest expression in vital lymphoid tissues (p < 0.05), whereas Blimp-1 expression was relatively equal among tissues (p> 0.05). In view of the conserved functions of Pax-5 and Blimp-1, we studied the progression of B cell differentiation in mucosal and systematic immunity by detecting the expression of these genes after infection with the parasite Cryptocaryon irritans and following vaccination with Vibrio harveyi. The expression level of grouper Blimp-1, IgM and IgT were significantly upregulated (p < 0.05), and the response occurred earlier in the systemic immune than the mucosal immune.
Sevi Sawestri, Ni Komang Suryati, Dina Muthmainnah
Situ Gede is one of the artificial lakes/reservoirs in Tasikmalaya, West Java. The lake has functioned as a source of household water needs, fisheries, and tourism. According to determine the development of water management requires information on the trophic status and water quality. This study aimed to obtain information on the trophic status and water quality of Situ Gede. The research was conducted in Situ Gede, Tasikmalaya, West Java, in 2018. Measurement and analysis of water quality parameters used the SNI and APHA methods, while the measurement of trophic status used the Carlson Trophic State Index (TSI). The relationship between water quality parameters and TSI scores was analyzed using Statistica version 8. Based on the analysis, the trophic status of Situ Gede ranged from 69.06-79.04, with an average of 74.61. This value indicated that Situ Gede's trophic status was on a eutrophic level. The physical and chemical parameters that affect the trophic status of Situ Gede are TP, pH, conductivity, TDS, and temperature. The TP values, conductivity, pH, and temperature at Situ Gede were still categorized as normal. The trophic of Situ Gede can be a source of fish growth. Moreover, in general, Situ Gede waters still have sufficient water quality for fish life. Therefore, Situ Gede has the potential to capture fisheries, recreational fisheries, and aquaculture.
Keywords:
Trophic status
Situ Gede
Fishery
Chlorophyll-a
Fish Reserve
Penaeid trawls often have poor ecological efficiencies measured as unwanted bycatches (with high discard mortality) and <100% effectiveness for all penaeids interacting with the ground gear (with some escape mortality). This study investigated the utility of varying ground-chain size (8- vs 10-mm diameter (Ø) stainless-steel chain) and the present or absence of a tickler chain (4-mm Ø) for improving efficiencies an Australian fishery diurnally targeting school, Metapenaeus macleayi and eastern king prawns, Penaeus plebejus. There were no treatment effects on wing-end spread and therefore areas trawled. Irrespective of the tickler chain, increasing the ground-chain Ø reduced catches of total penaeids (by 14%) and jellyfish, Catostylus mosaicus (by 39%)—results speculatively attributed to variation in ground contact and/or a slightly higher footrope in trawls with the 10-mm Ø chain. By comparison, installing the tickler chain had no effect on eastern king prawns, but increased catches of school prawns (by 1.13×) and bycatches of blue swimmer crabs, Portunus armatus (1.52×; a species with a low discard mortality) and jellyfish (1.23×), while reducing bycatches of two species with high discard mortalities: southern herring, Herklotsichthys castelnaui (by 38%) and squid, Uroteuthis sp. (37%). The results were attributed to the tickler chain producing (1) mechanical stimuli that augmented the capture of benthic-orientated school prawns (but not eastern king prawns owing to diel variations in emergence from the substrata), blue swimmer crabs and jellyfish; and (2) visual stimuli that possibly enabled some southern herring and squid to detect the trawl and escape. The data show tickler chains can improve trawl efficiency for penaeids with at least some positive effects on bycatch that should be rationalised in terms of species-specific vulnerabilities to unaccounted fishing mortality.
This study examines the distribution of the red scorpionfish, Scorpaena scrofa Linnaeus, 1758, in the Red Sea, in order to get a better picture of the distribution and dispersal of this species. The species is recorded for the first time from the Gulf of Aqaba, based on a specimen collected off Eilat, Israel at a depth of 400 m. This finding also confirms the occurrence of the species in the Red Sea and links up with a recent record from Saya de Malha Bank, western Indian Ocean.