Toritseju Begho, Arnold Ebuka Irabor, Ajibola Abeni Olaniyi
ABSTRACT This study examines how smallholder fish farmers perceive and respond to the environmental impacts of aquaculture, since their awareness, motivations and attitudes shape adoption of sustainable practices. Surveying 125 Nigerian fish farmers as a case example, the results show high environmental consciousness, with 93.7% recognizing the importance of sustainability. Water pollution, excessive chemical use and resource overexploitation are viewed as the main risks of unsustainable farming. Most farmers (78.6%) adopt one or more practices, particularly wastewater treatment and improved feed management. Adoption intensity varied substantially among regular adopters, with nearly half implementing three environmental practices and approximately one quarter adopting four or more practices. Adoption is motivated by sustainability beliefs, cost savings and market demand. Three farmer types emerge: sustainability‐oriented, economically motivated and reputation‐conscious. Farmers with broader environmental risk awareness adopt significantly more sustainable practices than those with limited perception ( p < 0.001). The number of motivational factors does not influence adoption intensity (F(5, 119) = 0.70, p = 0.629). To promote sustainable fish farming, multi‐dimensional support programs that integrate economic incentives with environmental values are most effective.
ABSTRACT Water hyacinth (hereafter, WH) is known as ‘the green devil' and becomes a threat to the fishing community whose livelihood solely relies on fishing activities. Although there are immense assessment studies related to WH, the real causal impact of this invasive weed on the fishing community has not yet been properly quantified. In filling this gap, the present study aimed to estimate the causal effect of WH on the net fishing income, technical efficiency level, income poverty and poverty gap around Lake Tana, Ethiopia. In addressing these, the study used about 593 randomly drawn fishers from both infested and non‐infested areas. Propensity score matching (PSM) and the ‘doubly robust' inverse probability‐weighted regression adjustment (IPWRA) methods were employed to estimate the average treatment effects of WH. In addition, heterogeneous treatment effect analysis was conducted to identify fishers who are most impacted by WH, given observable characteristics. The study provides adequate evidence that WH has a significant and negative impact on the welfare of fishers. However, the degree of causal effects on the outcomes of interest is not homogenous among fishers from infested areas. The results from the treatment heterogeneity reveal that the impact of WH is higher for artisanal and less experienced fishers than for their counterparts. These findings suggest that eradication (if possible) or control of WH in the study area could significantly contribute to the poverty reduction endeavours within the fishing community.
The archeospores produced from the blades of Pyropia yezoensis could develop into new blades, which is of significant both in cultivation and research. Nevertheless, the molecular mechanisms behind the formation and release of archeospores remained unclear. In this study, two strains of P. yezoensis with similar genetic backgrounds and opposite abilities for archeospores formation were used for genomic and transcriptomic analysis. Based on whole-genome resequencing, a total of 54,439 SNPs and 12,922 InDels were detected. Specifically, 211 SNPs and 8 InDels in coding regions could introduce codon change or frameshift mutation, resulted in sequence variations of corresponding encoded proteins. Furthermore, a total of 2888 differentially expressed genes (DEGs) between two strains were identified based on transcriptomic analysis, and 68 DEGs shared SNPs or InDels according to resequencing analysis, which may be associated with the processes related to the formation of archeospores. This study integrates genomic approaches to identify candidate genes and loci related to archeospores formation in P. yezoensis, laying a foundation for elucidating the regulatory mechanisms of archeospores formation and release.
Juan F. Alvarado, Belinda Vega, Claudia B. Cárcamo
et al.
The Chilean meagre, Cilus gilberti, emerges as a novel species to South American aquaculture. Nevertheless, the successful establishment of its cultivation necessitates careful consideration of productive parameters and tolerance to abiotic stressors. To address these challenges, the identifications of biomarkers emerges as a promising approach. Indeed, leptin stands out as a potential biomarker, given its multifaceted role. This study focuses on characterizing leptin in C. gilberti (cgLep) and assessing its gene expression in juveniles exposed to different culture and feeding conditions. The results indicated that cgLep coding sequence yields a 137-amino acid prohormone, preserving high relevant cysteine residues for maintaining its structural integrity. Basal cgLep gene expression profiles reveal its expression mainly in the liver, followed by white muscle. Conversely, its receptor (cgLepR) exhibits higher levels in white muscle. Additionally, it was observed that juveniles in a postprandial state exhibited an upregulation of hepatic cgLep. Simultaneously, the cgLepR showed a significant increase at brain level during the preprandial stage. The exposure to acute hypoxia revealed a notable upregulation of cgLep after two hours of low oxygen availability and returned to normoxia baseline after six hours post-hypoxia. Notably, when subjected to a prolonged daily hypoxia regimen, no significant differences in leptin mRNA expression were observed. This suggests a dynamic adaptive response of the C. gilberti leptin system to hypoxia. Finally, juvenile Chilean meagre cultivated at 15 Kg/m3 showcase significant individual variability in hepatic leptin expression levels when compared to those cultured at 25 or 35 kg/m3. These observations highlight that leptin primarily expresses in the liver and its expression is notably influenced by fasting periods and chronic stress induced by low stock density. This variability in leptin expression could potentially impact food intake, emphasizing the importance of considering these factors in the design and implementation of aquaculture practices for Chilean meagre.
Theresia Dwi Suryaningrum, Suryanti Suryanti, Rodiah Nurbaya Sari
et al.
Abstrak
Industri filet ikan patin menghasilkan hasil samping berupa kulit sebesar 7-8%. Untuk meningkatkan nilai ekonominya, kulit ikan patin dapat diolah menjadi camilan berupa keripik kulit. Penelitian ini bertujuan untuk melihat pengaruh perendaman kulit ikan dalam larutan asam cuka dan sodium bikarbonat (NaHCO3) serta kombinasinya dengan blansing dalam air panas terhadap karakteristik keripik kulit ikan patin yang dihasilkan. Sebelum dilumuri tepung dan digoreng menjadi keripik, kulit ikan patin direndam dalam larutan asam cuka 3% (v/v) atau larutan NaHCO3 1% (b/v) selama 15 menit serta kombinasi perendaman asam cuka, NaHCO3, dan blansing dengan air panas pada suhu 70-80°C selama 2 menit. Sebagai kontrol digunakan kulit patin yang hanya diblansing dan tanpa perlakuan. Hasil penelitian menunjukkan bahwa kombinasi perlakuan perendaman dalam larutan NaHCO3 1% (b/v) selama 15 menit dan blansing dalam air panas suhu 70-80°C selama 2 menit menghasilkan keripik kulit yang mempunyai kenampakan, aroma, kerenyahan, dan secara keseluruhan paling disukai panelis. Keripik kulit tersebut mempunyai kandungan protein 28,93±0,71%, dengan lemak 31,89±1,52%, abu 3,31±0,19%, air 2,40±0,38%, serta nilai TBA 0,14±0,02 mg MDA/kg. Keripik kulit dengan perlakuan ini mempunyai tingkat kecerahan dengan nilai L* paling tinggi, nilai +a* (derajat kemerahan) dan +b*(derajat kekuningan) yang rendah, serta tekstur yang lebih renyah (p<0,05) dibandingkan dengan keripik kulit yang diberi perlakuan perendaman dalam larutan asam cuka dan kontrol.
Abstract
The pangasius (catfish) fillet industry produces fish skin as a by-product by 7-8%. To increase its value-added, catfish skin can be processed into a snack of skin chips. This study aimed to examine the effects of soaking fish skin in a solution of vinegar and sodium bicarbonate (NaHCO3) and its combination with blanching in hot water on the characteristics of the catfish skin chips produced. The skin of the catfish before being coated with flour and fried was soaked in a solution of 3% (v/v) vinegar or 1% (w/v) NaHCO3 solution for 15 minutes, and a combination of soaking vinegar by blanching and NaHCO3 by blanching with hot water at a temperature of 70-80°C for 2 minutes. As a control, skin that was only blanched and without treatment was also observed. The experiment was carried out with 3 replications. The results showed that the combination of soaking in 1% (w/v) NaHCO3 solution and blanching in hot water at 70-80°C for 2 minutes resulted in catfish skin chips that had the most favorable appearance, aroma, crispness, and overall acceptance by the panelists. The catfish skin chips contained protein of 28.93±0.71%, a fat content of 31.89±1.52%, ash of 3.31±0.19%, the water of 2.40±0.38%, and a TBA value of 0.14±0.02 mg MDA/kg. Catfish skin chips with this treatment had a brightness level with the highest L* value, a low +a* value (degree of redness), and +b*(yellowish), and a crispier texture, which were significantly different (p<0.05) from the catfish skin chips treated with soaking in an acid solution and control.
AbstractRecreational fishing is a commonplace leisure activity within the developed world but can generate tension when activities conflict with conservation agendas. A potential conflict arises over the use of European river lamprey, Lampetra fluviatilis (L.), a protected species, by UK coarse (freshwater non‐salmonid) predator anglers. This study used geographically stratified interviews with 69 predator anglers to explore attitudes towards the use of lamprey as bait, their conservation status and knowledge of biosecurity regulations. Most participants used lamprey as bait to some degree and agreed that, if threatened by exploitation, a ban on their use as angling bait should be implemented. Ordinal regression analysis indicated the presence of a subset of anglers who value lamprey as bait more than others and may oppose conservation efforts. The benefits of the potential establishment of bait certification schemes are also considered.
The need for gouramy (Osphronemus gouramy) continues to increase, this can be seen from the gouramy trade which has begun at the egg stage, so research is needed that affects the number of eggs (fecundity) of the gouramy parent. In this study aims to determine the relationship between age and fecundity of gouramy. The research method used is comparative descriptive. Main gouramy fish is divided into 3 based on their age, pond A is 2.5 years old, pond B is 4 years old and pond C is 8 years old. Observations were made by taking eggs from the nest in each pond then counted manually. The observations showed that the parent who was 4 years old had the highest level of fecundity.
Keyword : Age, Fecundity, Osphoronemus gourami
Ali Khosravanizadeh, Abdolali Rahdari, hossien moradian
Exogenous multi-enzyme supplementations can eliminate the effects of antinutritional factors and improve the growth performance of aquatic animals. The purpose of this study was to investigate utilizing Kemin multi-enzyme supplementation in the diet and its effects on growth factors, body composition, and some blood biochemical parameters in Carassius auratus gibelio. The experiment was conducted in a completely randomized experimental design with 5 treatments and 3 replications. The Kemin at 4 levels of 0, 250, 500, 750, and 1000 mg/kg was added to the diet and given the experimental diets to fishes for 8 weeks and growth factors, Weight growth percent (WGP), specific growth rate (SGR), feed conversion ratio (FCR), Condition factor (CF), Protein efficiency ratio (PER) were studied. Body composition and blood biochemical factors (glucose, total protein, albumin, cholesterol, and triglyceride) were measured and evaluated. Different treatments of CF were not significantly different from each other (P> 0.05). But WGP, SGR, FCR and PER, the enzyme levels of 500, 750, and 1000 mg/kg were significantly different from the control group (P <0.05). Body composition and blood biochemical parameters were not significantly different between enzyme levels (P> 0.05). Based on the results of this study, it seems that Kemin multi-enzyme supplementation diets can improve the growth and FCR in Carassius auratus gibelio.
Nutrition. Foods and food supply, Aquaculture. Fisheries. Angling
Nurus Samsiyah, Anita Dewi Moelyaningrum, Prehatin Trirahayu Ningrum
Abstrak
Kualitas garam sangat ditentukan oleh perlakuan dan penanganan yang diberikan pada saat pra produksi, proses produksi maupun pasca produksi. Kontaminan Pb dalam garam dapat bersumber dari lingkungan perairan laut sebagai bahan baku, tanah sebagai media / tempat produksi garam dan lingkungan udara dimana proses produksi garam berlangsung di lahan terbuka. Tujuan penelitian ini adalah untuk menganalisis kadar logam berat timbal (Pb) dalam garam di Kabupaten Pamekasan. Jenis penelitian ini adalah jenis deskriptif. Teknik pengumpulan data penelitian melalui observasi dan wawancara. Hasil observasi menunjukkan bahwa rata-rata kadar logam berat timbal (Pb) di Kabupaten Pamekasan masih di bawah batas maksimum yang telah ditentukan dalam SNI 3556-2010 dan SNI 7387-2009 yaitu <10 ppm dengan kadar Pb terendah 0,066 ppm dan tertinggi 0,162 ppm. Proses produksi garam kurang sesuai dengan standar yang telah ditetapkan. Oleh karena itu, perlunya penangangan yang baik pada pra produksi, proses produksi hingga pasca produksi pembuatan garam agar kadar Pb tidak meningkat.
Abstract
The quality of salt is very determined by the treatment and handling given during the pre-production, production and post-production processes. Pb contamination in salt can be sourced from the marine environment as raw material in the process of making salt, the soil environment as a medium / place of salt production and the air environment where the salt production process takes place in an open area. The aim of research was to analyze levels of lead heavy metals (Pb) of salt in Pamekasan Regency. This research is a descriptive analysis. The techniques of data collecting of this research are observation and interview. Observations indicate that the average level of heavy metal lead (Pb) in Pamekasan regency is still below the maximum limit specified in SNI 3556-2010 and SNI 7387-2009 is <10 ppm which is the lowest grade of 0.066 ppm and grade the highest is 0.162 ppm. The salt production process is not in accordance with established standards The Therefore, the need for good handling in pre-production, production processes to post-production of salt production so that Pb levels do not increase.
To determine the age and growth of Uroteuthis chinensis and U. edulis, growth increments of the lateral dome of the statolith were used in the present study. Specimens of the two species caught in the South China Sea (SCS) and East China Sea (ECS) were used to compare the age and growth differences between sexes. In the present study, we found the two species have similar lifespans of less than 200 days. We also found that there were significant differences in the relationships between mantle length and body weight for two species and for both sexes in the same species. The back-calculated hatching date for the two species was similar, i.e. October to January for specimens caught in spring, and March to June for specimens caught in summer (U. edulis) or autumn (U. chinensis). Exponential and logistic growth curves were fitted to build the age and mantle length relationship. Both growth curves showed that U. chinensis has a larger mantle length than U. edulis at the same age. The results of the growth rates also showed that U. chinensis grows faster than U. edulis. However, there are discrepancies between previous studies and the present study on the lifespan of the two species. Also, the sample size of the present study is small especially for U. edulis. Hence, future studies should be conducted to validate the daily periodicity of growth increment in the regions of statolith (except for the lateral dome which has been validated) and the sample size should be increased for age and growth studies. Keywords: Uroteuthis chinensis, Uroteuthis edulis, Age, Hatching date, Growth
Selecionaram-se sementes de ostra Crassostrea brasiliana (Lamarck, 1819) utilizando dois métodos de "castigo" na região entremarés no complexo estuarino-Iagunar de Cananéia: sementes colocadas sobre estrado, a 25 cm do solo, e sementes dispostas diretamente sobre o solo previamente tratado com cascalho. Os períodos dos testes de "castigo" iniciaram-se em duas épocas do ano: verão, prolongando-se de dezembro/1979 a agosto/1980, e outono, de abril/1980 a dezembro/1980. Após oito meses de "castigo", as sementes sobre estrado apresentaram taxas de sobrevivência de 12,8% e 17,2%, enquanto as sementes "castigadas" sobre o solo, taxas de 9,3% e 7,1%, para os períodos de teste com início no verão e outono, respectivamente. As alturas médias finais das ostras foram 18,9 mm e 23,3 mm no estrado e 23,5 mm e 25,8 mm no solo, para os períodos com início do "castigo" no verão e outono, respectivamente. Assim, observou-se que o "castigo†de sementes sobre estrado, tanto numa época (com início no verão) como noutra (com início no outono), apresentou, em comparação com o tratamento sobre o solo, maior taxa de sobrevivência.
Kasus kematian massal ikan Gurami di Sentra Budidaya Ikan Gurami, Desa Beji, Kecamatan Kedung Banteng, Kabupaten Banyumas, Jawa Tengah berdampak pada menurunnya produksi telur dan benih ikan Gurami. Penelitian ini bertujuan untuk mengidentifikasi patogen penyebab kematian pada ikan Gurami. Metode yang digunakan metode survei dengan pengambilan sampel secara acak, kemudian diidentifikasi keberadaan patogen pada sampel ikan Gurami. Hasil identifikasi patogen pada ikan Gurami menunjukkan adanya infeksi Bakteri (Aeromonas hydrophila, Aeromonas sobria), Parasit (Henneguya sp., Trichodina sp., Vorticella sp.) dan Jamur (Aspergillus sp.). Penelitian ini menunjukkan bahwa kematian massal pada ikan Gurami disebabkan oleh serangan bakteri, parasit, dan jamur.
Kata Kunci: ikan Gurami, kematian massal, bakteri, parasit, jamur.
Suhas Kumar Dan, Goutam Banerjee, Ankita Nandi
et al.
Twelve isonitrogenous (35 % crude protein) and isocaloric (18.0 kJ/g) diets were formulated incorporating raw and fermented soybean meal (SBM) at 15%, 30%, 45% and 60% levels by weight. Two phytase-producing bacterial strains, Bacillus cereus LRF5 and Staphylococcus caprae CCF2 isolated from the gut of adult Labeo rohita and Catla catla, respectively were used for fermentation of SBM. Fermentation of SBM was effective in reducing the anti-nutritional factors, trypsin inhibitor and phytic acid and enhancing protein, lipid and mineral concentration. The response of L. rohita, fingerlings (initial weight 3.33±0.07 g) fed the experimental diets for 100 days was compared with fish fed a fish meal based diet. In terms of growth, feed conversion ratio and protein efficiency ratio, diet S7 containing 45% SBM fermented with B. cereus LRF5 resulted in a significantly (P<0.05) better performance of fish. The overall performance of L. rohita fed fermented SBM incorporated diets was better in comparison to those fed raw SBM incorporated diets. The apparent digestibility of nutrients and minerals was significantly (P<0.05) higher in fish fed diet S7. The maximum deposition of protein in the carcass was recorded in fish fed diet S7. Diets containing fermented SBM reduced fecal P levels.
Javier Porobic, Carolina Parada, Billy Ernst
et al.
El archipiélago de Juan Fernández y el de las islas Desventuradas, corresponden a dos pequenos grupos de islas oceánicas, separadas entre sí 460 mn y ubicadas aproximadamente a 360 mn frente a la costa chilena. La economía local de estas islas se basa casi exclusivamente en la extracción y comercialización de recursos marinos, focalizados principalmente en la explotación de la langosta (Jasusfrontalis). Esta especie endémica se encuentra distribuída en ambos archipiélagos conformando una metapoblación, donde su dinámica y estructura poblacional sería modulada por forzantes oceanográficos, especialmente durante su prolongada fase larval planctónica. Se evaluó la estructura poblacional y el grado de conectividad-retención dentro y entre las diferentes islas mediante el uso de modelos biofísicos acoplados (modelos hidrodinámicos provenientes del modelo OFES y un modelo individuo basado de J. frontalis). El análisis de los resultados del modelo hidrodinámico indica la presencia de estructuras de mesoescala asociadas al sistema de islas. Índices provenientes del modelo biofísico muestran niveles importantes de conectividad-retención dentro y entre los sistemas de islas y una fuerte variación interanual de estos. Los resultados de la modelación biofísica indican que la varibilidad en el reclutamiento asociado al archipiélago de Juan Fernández depende mayoritariamente de larvas originadas en este mismo sistema, con un aporte importante de reclutas hacia el archipiélago de las Desventuradas. Se realizaron estudios de sensibilidad del modelo biofísico para identificar forzantes potenciales de las variables dependientes del modelo (e.g. índices de conectividad-retención), resultando en que los patrones temporales y espaciales reproductivos, la duración del estadio larval y la temporada (ano) son altamente significativos. Finalmente, se propone que J. frontalis presenta una estructura metapoblacional con un alto nivel de conectividad en el archipiélago de Juan Fernández y un fuerte aporte de larvas hacia las islas Desventuradas. Estos flujos se ven determinados principalmente por el acoplamiento entre los factores biológicos y los factores oceanográficos imperantes.<br>Located approximately 360 nm off the coast of Chile there is a disjoint realm of two small oceanic islands systems, the Juan Fernández and the Desventuradas archipelago. Currently the local economy of the islands is almost exclusively supported by the harvest and trade of marine resources, focusing mainly on the exploitation of the rock lobster (Jasus frontalis). This endemic species is distributed in both archipelagos, forming a metapopulation, whose population structure and dynamic is modulated by oceanographic forcing, especially during its extended planktonic larval phase. The population structure and the conection-retention within and between islands was assessed, based on the use of coupled biophysical model (the hidrodynamics model OFES and an individual-based model of J. frontalis). The analysis of the hydrodynamic model predictions showed the presence of mesoscale structures associated with the islands systems. The simulation results indicated significant levels of connectivity-retention within and between island systems showing also a strong interannual variation of these. Biophysical modeling results indicated that recruitment varibility associated with the Juan Fernández archipelago depends mainly on larvae originated within this system, which as well will contribute with recruits to the Desventuradas archipelago. The sensitivity analysis of the biophysical model to identify the potential biophysical forcing of the dependent variables of the model (e.g. connectivity-retention index), resulted in that temporal and spatial patterns reproductive larval stage duration and season (year) are highly significant factors. Finally, a metapopulation structure for J.frontalis, with a high level of connectivity in the archipelago of Juan Fernandez and a considerable amount of larvae in the Desventuradas islands is proposed. These fluxes are determined mainly by the coupling between prevailing biological and oceanographic factors.
Laboratory experiments with natural zooplankton communities were carried out to study the effects of two contrasting temperature regimes: constant temperature (15, 20, and 25 °C) and graded changes in temperature. The graded regime consisted of repeated sustained (three weeks) controlled stepwise temperature changes of 5 or 10 °C within 15–25 °C on the population dynamics of four dominant species of lake littoral zooplankton, Daphnia longispina (Müller, 1785), Diaphanosoma brachyurum (Lievin, 1848), Simocephalus vetulus (Müller, 1776) and Chydorus sphaericus (Müller, 1785). The results show that controlled stepwise changes (positive or negative) in temperature within the ranges of 15–20, 20–25, and 15–25 °C can exert either stimulating or inhibitory effect (direct or delayed) on the development of D. longispina and S. vetulus populations. The development of D. brachyurum and Ch. sphaericus, both more steno-thermophile, was only stimulated by a stable elevated temperature (25 °C). These results support the previously formulated hypothesis that, in determining the ecological temperature optimum of a species within a natural community, it is not enough to define its optimum from constant, cyclic or random temperature fluctuations, but also from unidirectional stepwise changes in temperature. These stepwise changes may also induce prolonged or delayed effects.
The coastal demersal fish assemblage exploited commercially by the Viareggio fleet was assessed in order to define its exploitation status and sustainability. A production model was used provided management benchmarks for the species for which available data are limited. The ASPIC Surplus production model was used. The results showed a depleted population for most of the species involved (B2008/B0 between 0.05 and 0.35) with high relative fishing mortality (F2008/FMSY between 1.18 and 1.64). Population projections using ASPIC-P allowed the exploitation strategies to be evaluated for a 10-year period. None of the populations are predicted to recover to BMSY if fishing effort remains at the 2008 levels. A reduction in effort of about 40% should increase the biomass in the medium-term of most of the species to BMSY or over, with a fairly good increase in yields of the most valuable species.