Effects of Parasitism on the Production and Productivity of caged Oreochromis niloticus in Winam Gulf of L. Victoria

The general objective of this study was to assess the effects of parasitism on the production and productivity of caged Oreochromis niloticus in Winam Gulf of L. Victoria. With the need to increase food production through fish products amid overfishing and pollution stress in the lake, cage farming is seen to have the potential to bridge the fish supply and demand gap continues to widen. Cage culture is a new technology in the offing that needs to be explored to justify its potential. Fish parasites are always a threat in an enclosed culture system and because of this, it is necessary to assess their effects on fish condition factors before recommendation. It is because of this reason that a total of 480 caged Oreochromis niloticus were purchased and examined for parasites using the recommended procedures for parasitological analysis. The class Trematoda which included seven taxa were found to be the most common and prevalent parasites in cages of the Winam Gulf. This was attributed to the presence of piscivorous birds which are definitive hosts seen more often around the culture systems and also overstocking observed and reported during the study period which increases the spread and transmission of parasites from one fish to another. Despite the prevalence, infestation did not affect the fish condition factor in all the study areas as the majority of infected fish recorded between good and excellent body condition factors. This was due to low mean intensities recorded and a shorter period of exposure to parasitic infestation as most farmers were barely 3 years into the system. In conclusion, for the government to explore the blue economy and achieve the Vision 2030 and SDGs on food security and poverty reduction by 2030, efforts to promote commercial cage culture enterprises in the Winam Gulf must be bolstered, provided that cages are located in deep waters with low concentrations in specific areas and low stocking densities to avoid compromising the environment.

Synchronicity of Condition Factor with Reproductive Development in Rainbow Snakehead (Channa bleheri Vierke, 1991)

Background: Condition factor is an important factor to determine the general well being of any species. It is influenced by different factors like feeding, age of the fish, season, development of gonads etc. Reproductive development on other hand is a crucial factor in determining the condition of fish as gonad weight has certain impact on increasing the weight of fish as well as the condition of the fish. The experiment was thus to determine whether there is any synchronicity of reproductive development in the near threatened snakehead Channa bleheri with respect to its condition factor value.Methods: The condition of C. bleheri was closely monitored based on lenth-weight data round the year. The gonadal development of the species was determined calculating the Gonado-Somatic Ratio (GSR) as well as histological observation of the gonads.Result: It was found that the value of condition factor was directly proportional to the gonadal development which signifies the importance of gonad development in determining the fish condition. As there are many established factors that determine a fish condition, the inputs drawn out from the reproductive development can help to determine the condition of the fish.

Plasticity in Reproductive Traits, Condition and Energy Allocation of the Non-Native Pyrenean Gudgeon Gobio lozanoi in a Highly Regulated Mediterranean River Basin

The invasion success of non-native fish, such as Pyrenean gudgeon Gobio lozanoi in several Iberian rivers, is often explained by the expression of its life history traits. This study provides the first insights into the reproductive traits, fish condition, and energy allocation (protein and lipid contents of tissues) of this species, along a longitudinal gradient in one of the most regulated river basins in the Iberian Peninsula, the Segura river. Larger sizes of first maturity, higher fecundity and larger oocytes were found in fluvial sectors with the most natural flow regimes, characterised by a low base flow with high flow peaks in spring and autumn. A delay in the reproductive period, lower fish condition and no differences in sex-ratio were observed in fluvial sectors with a high increase in base flow and notable inversion in the seasonal pattern of flow regime. Lipid contents in the liver and gonads were stable during the reproductive cycle and decreases in muscle were noted, whereas ovarian and liver proteins increased. In relation to energy allocation for G. lozanoi, an intermediate energy strategy was observed between income and capital breeding. Our results support the hypothesis that the high plasticity of G. lozanoi population traits plays a significant role in its success in a highly regulated Mediterranean river basin. Understanding the mechanisms by which flow regulation shapes fish populations in Mediterranean type-rivers could inform management actions.

Temporal changes in the gut microbiota in farmed Atlantic cod (Gadus morhua) outweigh the response to diet supplementation with macroalgae

Background Aquaculture successfully meets global food demands for many fish species. However, aquaculture production of Atlantic cod (Gadus morhua) is just 2.5% of total market production. For cod farming to be a viable economic venture specific challenges on how to increase growth, health and farming productivity need to be addressed. Feed ingredients play a key role here. Macroalgae (seaweeds) have been suggested as a functional feed supplement with both health and economic benefits for terrestrial farmed animals and fish. The impact of such dietary supplements to cod gut integrity and microbiota, which contribute to overall fish robustness is unknown. The objective of this study was to supplement the diet of juvenile Atlantic cod with macroalgae and determine the impacts on fish condition and growth, gut morphology and hindgut microbiota composition (16S rRNA amplicon sequencing). Fish were fed one of three diets: control (no macroalgal inclusion), 10% inclusion of either egg wrack (Ascophyllum nodosum) or sea lettuce (Ulva rigida) macroalgae in a 12-week trial. Results The results demonstrated there was no significant difference in fish condition, gut morphology or hindgut microbiota between the U. rigida supplemented fish group and the control group at any time-point. This trend was not observed with the A. nodosum treatment. Fish within this group were further categorised as either ‘Normal’ or ‘Lower Growth’. ‘Lower Growth’ individuals found the diet unpalatable resulting in reduced weight and condition factor combined with an altered gut morphology and microbiome relative to the other treatments. Excluding this group, our results show that the hindgut microbiota was largely driven by temporal pressures with the microbial communities becoming more similar over time irrespective of dietary treatment. The core microbiome at the final time-point consisted of the orders Vibrionales (Vibrio and Photobacterium), Bacteroidales (Bacteroidetes and Macellibacteroides) and Clostridiales (Lachnoclostridium). Conclusions Our study indicates that U. rigida macroalgae can be supplemented at 10% inclusion levels in the diet of juvenile farmed Atlantic cod without any impact on fish condition or hindgut microbial community structure. We also conclude that 10% dietary inclusion of A. nodosum is not a suitable feed supplement in a farmed cod diet.

Pola pertumbuhan dan faktor kondisi ikan sembilang (Potosus canius) di Teluk Bintan Kepulauan Riau

One of the economically important fish included in the Plotosidae family is the Sembilang Fish. This study aims to determine the growth patterns and condition factors of the Sembilang fish. The research was conducted in July 2018. The locations of the Sembilang Fish sampling station include Dompak Island Bay, Bugis Village Bay, Madong Bay, Pengujan Bay and Tanjung Uban. The total sample of Sembilang Fish that has been obtained is 150, consisting of 80 males and 70 females. Total length ranges from 19.7-66 cm, with weights ranging from 33.68-960 g. The mode of distribution of the frequency of the fish caught during the study was in the second class interval, namely 25.7-30.7. The relationship between the length and weight of male Sembilang fish is W = 0, 0268L2,5378 and the female is W = 0, 00542L2,3347. The growth pattern of Sembilang fish, both male and female, is negative allometric which shows the length growth is faster than the weight. Fish condition factors obtained during the study ranged from 0.723 to 1.166.Keywords:BintanCondition FactorLength-weight-relationshipPlotosus caniusSembilang fish ABSTRAKSalah satu ikan ekonomis penting yang termasuk dalam famili Plotosidae adalah Ikan Sembilang. Penelitian ini bertujuan untuk mengetahui pola pertumbuhan dan faktor kondisi ikan sembilang. Penelitian dilaksanakan pada bulan Juli 2018. Lokasi stasiun pengambilan sampel Ikan Sembilang diantaranya Teluk Pulau Dompak, Teluk Kampung Bugis, Teluk Madong, Teluk Pengujan dan Tanjung Uban. Total sampel Ikan Sembilang berjumlah 150 ekor, terdiri dari 80 ekor jantan dan 70 ekor betina. Ukuran panjang total berkisar antara 19,7-66 cm, dengan berat berkisar antara 33,68-960 g. Modus distribusi frekuensi ikan sembilang yang tertangkap selama penelitian ada pada selang kelas kedua yaitu 25,7-30,7. Hubungan panjang dan bobot Ikan Sembilang jantan adalah W = 0, 0268L2,5378 dan betina adalah W = 0, 00542L2,3347. Pola pertumbuhan Ikan Sembilang baik jantan maupun betina adalah alometrik negatif yang memperlihatkan pertumbuhan panjang lebih cepat daripada bobotnya. Faktor kondisi ikan selama penelitian nilainya berkisar antara 0,723 hingga 1,166.Kata kunci: BintanFaktor kondisiHubungan panjang-bobotPlotosus caniusIkan Sembilang

PROTOTYPE MONITORING SUHU BERBASIS MIKROKONTROLER PADA COOL BOX IKAN MENGGUNAKAN SENSOR DS18B20 DENGAN METODE FUZZY

<p><em>Often fish supply in to the consumers need long relatives distance and much time. Meanwhile the consumers always want fresh fish. The problem occurred was broken stock of fresh fish in every shipping and happened almost all the time. It made fish became stale and made supplier got lose. The study was took place in Batulicin Simpang Empat in a harbor (Pelelangan Pembongkaran Ikan) until now the handling of fish catches generally used ice block in the usual cool box. Using ice block is one of easiest method. Although, using ice block only could maintain low temperature in short time whereas the ideal temperature of cool box should be 10 Celsius measured by usual temperature’s device room. In shipping process, the driver unpack the cool box to checked temperaturemanually. This matter waste time and cost because the driver should provide extra ice block to maintain low temperature of cool box. In order to resolve the problem, monitoring could be done automatically by using a microcontroller chip in the cool box with DS18B20 censor and fuzzy methodbase microcontroller. The purpose was supplier could be helped to monitoring the stabilities of cool box temperature used website. This system is made by computerization. It would make supplier job easier because driver able to check fish condition without unpack the cool box and made time, energy and cost more efficient.</em></p><p><em><strong>Keywords</strong></em><em>: Temperature Censor, Fish cool box microcontroller, Fuzzy method, and website</em></p><p><em>Seringkali d</em><em>alam </em><em>p</em><em>enyuplaian </em><em>i</em><em>kan kepada konsumen membutuhkan jarak dan waktu yang relatif panjang, sedangkan konsumen selalu mengharapkan ikan segar. </em><em>P</em><em>ermasalahan </em><em>besar </em><em>yang dihadapi dalam produk</em><em>si</em><em> ikan segar, yaitu persediaan yang rusak (broken stock) </em><em>dalam jumlah yang banyak</em><em>, sehingga </em><em>jumlah</em><em> ikan yang membusuk </em><em>menjadi berlebihan </em><em>dan akhirnya mengalami kerugian.</em><em> </em><em>Di </em><em>Batulicin Simpang Empat</em><em>,</em><em> tempat dilakukanya penelitian, </em><em>tepatnya di </em><em>pelabuhan PPI (Pelelangan Pembongkaran Ikan)</em><em>,</em><em> penanganan hasil tangkapan ikan </em><em>saat ini masih</em><em> menggunakan pendinginan es batu di dalam cool box biasa. Penggunaan es merupakan salah satu cara yang paling mudah dilakukan. Akan tetapi, pendinginan dengan menggunakan es batu hanya dapat mempertahankan suhu rendah dalam waktu yang singkat sedangkan suhu ideal dari dalam cool box adalah 10 C yang diukur dengan menggunakan alat suhu ruangan biasa. Jadi, saat perjalanan driver akan membongkar muatan dan mengecek apakah suhu turun atau tidak secara manual. Hal ini sangat memakan waktu dan biaya karena supplier selalu membawa cadangan es untuk berjaga-jaga jika suhu turun didalam cool box tersebut.</em><em> </em><em>Untuk mengatasi permasalahan di atas, monitoring dapat dilakukan secara otomatis dengan memanfaatkan sebuah chip mikrokontroler pada cool box dengan sensor DS18B20 bersama metode fuzzy berbasis mikrokontroler. Tujuannya agar supplier dapat terbantu untuk memonitoring kestabilan suhu cool box dengan menggunakan website. Karena sistem dibuat terkomputerisasi maka akan memudahkan kinerja dari supplier atau driver sehingga driver dapat memonitor kondisi ikan di dalam cool box tanpa harus membongkar muatan dan hal ini dapan mengefisiensikan waktu, tenaga, dan biaya karena suhu cool box tetap terjaga dengan baik dan mudah.</em></p><p><em><strong>Kata kunci</strong></em><em>: Sensor Suhu, Mikrokontroler Cool Box Ikan, Metode Fuzzy, dan website</em></p>