The effect Calotropis gigantea leaf extract on eggs hatchability and survival of Barbonymus gonionotus larvae

This study aims to determine the Calotropis gigantea extract against hatchability of Barbonymus gonionotus eggs infected with pathogenic fungi. The research was conducted at Fish Seeds Center Krueng Batee, Aceh Barat Daya district, from July to August 2020. Statistical analysis used a completely randomized design (CRD) method with 6 treatment and 3 replications for each treatment. The treatments were carried out by immersing the Barbonymus gonionotus eggs into C. gigantea leaf extrcact. Namely Control (without extract), A (400 ppm extract), B (800 ppm extract), C (1200 ppm extract), D (1600 ppm extract), and E (2000 ppm extract). ANOVA test results showed that the addition of C. gigantea leaf extract had asignificant effect (P<0.05) on hatchability and survival of B. gonionotus larvae. The best treatment was achieved at the C treatment (800 ppm extract) with 88 % hatching rate and 92,54 % survival rate. From the results of this study, it is known that using C. gigantea leaf extract can increase the hatchability of B. gonionotus fish eggs infected with the Saprolegnia sp. pathogen, which means it can also increase the production of fish seeds.

Embryogenesis of climbing perch fish Anabas testudineus Bloch 1792 at incubation temperature of 28°C

Information on the embryonic development of fish is important to understand the early life history of fish, this information is useful for fish breeding, especially in crossbreeding and genetic engineering. Therefore, this study aimed to observe the process of embryonic development and the incubation time of climbing perch eggs which were incubated at a temperature of 28 °C. The results showed that the embryonic development of betok fish was divided into six phases, namely the cleavage phase (3 hours and 5 minutes), morula (4 hours and 30 minutes), blastula (5 hours, and 40 minutes), gastrula (8 hours, and 47 minutes), organogenesis (15 hours, and 39 minutes) and hatched. At an incubation temperature of 28 °C, the climbing perch fish eggs hatched 18 hours and 38 minutes after fertilization.Introduction

Comparative Analysis The Effect of Iodine, Ozone, and Peracetic Acid as A Disinfectant of Cantang Grouper Egg

Problems in the fish hatchery sector often occur such as high egg mortality or low quality of fish eggs. Optimizing biosecurity is one of the efforts to improve the quality of fish eggs, for example by adding disinfectants such as iodine, ozone, and peracetic acid. The use of chemical disinfectants will produce good results if the right dose, time, and commodity are used. In this study. This research aims (1) to determine whether the use of chemicals including iodine, ozone, and peracetic acid had an effect as a disinfectant to increase the hatching rate of grouper fish, (2) to determine the level of effectiveness and efficiency of the use of chemicals as a disinfectant. This research is an experimental research type. The research subjects included in the study were cantang grouper fish eggs at PT. Pakarti Daksa Segara who used the exploratory sampling method. The conclusion of this study indicates that there is an influence on the growth rate of the use of iodine, ozone and, peracetic acid chemicals as disinfectants of cantang grouper eggs and there is a comparison of the effectiveness and efficiency of the use of the three chemicals which includes the percentage of the hatching rate, the cost of the disinfectant material and the time, which is needed in the use of the disinfectant. Iodine has the best level of effectiveness from the comparison of hatching eggs of cantang grouper and peracetic acid is the most efficient type of chemical.

Seasonal variation in the diet and the morphometric parameters of the genus Pseudo-phoxinus sp. (Cyprinidae) in Eastern Algeria

The diet and the morphometric parameters of the Pseudophoxinus sp. (Cyprinidae) in the El Mellah ravine (M’sila, Algeria) were studied by determining body measurements and analyzing the contents of digestive tracts of 320 fish from December 2018 to November 2019. The obtained results show marked diversity within the fish species diets, which can be grouped into three main fractions: (i) a plant fraction; (ii) an animal fraction composed mainly of invertebrate prey; and (iii) fraction consisting of fish eggs (digested by males during the breeding season). The plant fraction was present in all the analyzed digestive tracts, mainly being composed of phytoplankton (algae), namely, Spirogyra sp., Melosira sp. and Navicula sp. with the total relative abundances of 38.7%, 34.4% and 4.1%, respectively. On the other hand, the animal fraction was represented by the Chironomus sp., Austrosimulium sp., and Ecdyonurus sp. dipterans with a total relative abundance of 7.3%, 6.7% and 5.9%, respectively. Pseudophoxinus sp. eggs can also be considered as part of this fraction with the total relative abundance of 2.9%. The age of the fish seems to have an influence on their feeding behaviour. The juveniles of Pseudophoxinus sp. in the study area had a purely phytophagous diet, while adults showed a phytophagous behaviour with an omnivorous tendency. The present study shows that not only the age of the fish but also the seasonal changes (climatic conditions and entry into the breeding season) may have a significant influence on the diet and morphometric parameters of Pseudophoxinus sp. in El Mellah ravine.

Sexual dimorphism in size and shape of the head in the sea snake Emydocephalus annulatus (Hydrophiinae, Elapidae)

In snakes, divergence in head size between the sexes has been interpreted as an adaptation to intersexual niche divergence. By overcoming gape-limitation, a larger head enables snakes of one sex to ingest larger prey items. Under this hypothesis, we do not expect a species that consumes only tiny prey items to exhibit sex differences in relative head size, or to show empirical links between relative head size and fitness-relevant traits such as growth and fecundity. Our field studies on the sea snake Emydocephalus annulatus falsify these predictions. Although these snakes feed exclusively on fish eggs, the heads of female snakes are longer and wider than those of males at the same body length. Individuals with wider heads grew more rapidly, reproduced more often, and produced larger litters. Thus, head shape can affect fitness and can diverge between the sexes even without gape-limitation. Head size and shape may facilitate other aspects of feeding (such as the ability to scrape eggs off coral) and locomotion (hydrodynamics); and a smaller head may advantage the sex that is more mobile, and that obtains its prey in narrow crevices rather than in more exposed situations (i.e., males).

The Evolution of Alternative Buoyancy Mechanisms in Freshwater Fish Eggs

Alternative reproductive tactics (ARTs) are behavioural, morphological, and physiological traits associated with alternative reproductive phenotypes within a population or species. ARTs are widespread in nature, and are a particular feature of teleost fishes. However, few studies have examined egg buoyancy mechanisms in the context of the evolution of ARTs in freshwater fishes. In marine fishes, egg buoyancy is achieved chiefly through hydration. While the buoyancy of freshwater fish eggs has been suggested to be determined primarily through the presence of oil droplets, the majority (60%) of freshwater pelagic eggs do not possess an oil droplet. We applied a physical model of buoyancy to understand the contributions of oil droplets and hydration to the buoyancy of pelagic freshwater fish eggs. We further used phylogenetic regression to estimate the effect of the relative size of the perivitelline space, habitat and parental care on the occurrence of oil droplets, while controlling for non-independence among species due to phylogenetic relatedness. Our analysis demonstrates that the probability of oil droplets in freshwater pelagic eggs exhibits a significant negative relationship with the size of perivitelline space, which may reflect a trade-off relating to energy allocation in contrasting habitats. We also demonstrate a positive association between the probability of oil droplets and the provision of parental care and occupancy of lentic habitats. These findings indicates the evolution of contrasting buoyancy mechanisms as novel ARTs in freshwater fishes. A theoretical model in combination with empirical analysis indicate the evolution of novel ARTs in freshwater fishes as adaptive responses to flow conditions.

Association between the Socioeconomic Status of Households and a More Sustainable Diet

Objective: A sustainable diet is an affordable diet with low environmental impact, high food security, and sufficient healthiness. The present study aimed to assess the correlation between the socioeconomic status of households and a sustainable diet. Design: The food basket and socioeconomic data of Iranian households were evaluated during 2016-2018. The households were classified based on the sustainability of their diet by determining the dietary carbon footprint, dietary water footprint, lower dietary costs of the household than the median, and a higher dietary quality index than the median. Logistic regression was used with four models to calculate the odds ratio (OR) of a more sustainable diet as the dependent variable regarding the different quartiles of socioeconomic status (SES) as the independent variable. Setting: Iran. Participants: Iranian households (n 102,303), nationally representative, were studied. Results: Lower SES was associated with the higher OR of a sustainable diet (OR: 0.90; CI: 0.87-0.91). Higher quartiles of SES compared to the lower SES group indicated the higher energy intake and consumption of more dairies, meat, poultry, fish, eggs, legumes, nuts, and fruits, as well as the lower intake of bread, cereal, rice, and pasta. Conclusion: In countries such as Iran, where nutrition transition occurs rapidly, better economic and social levels in the populations with a higher SES are associated with increased energy intake and higher consumption of animal-based foods, which decreases sustainable diets compared to the groups with a lower SES.

Köyceğiz-Dalyan Lagün Ekosistemi Kefal Populasyonlarının Büyüme Performans İndeksleri

As it is common in tropical and temperate zones, mullet species constitute the most important fish species caught along the coast and estuaries of Turkey. In terms of ecology, tourism and and fish productivity (52 kg/ha), Koycegiz-Dalyan Lagoon Ecosystem (KDLES) is the most important lagoon, with a 5500 ha surface area, is the Mediterranean Coast of Turkey. In the dalyan (barrier fish trap) systems; approximately 225 tons (80-405 tons) of mullets are caught to obtain 5 tons of dried fish eggs per year. Seventy percent of fish production in the lagoon is composed of mullets. The mullet samples were collected monthly between October 1992 and September 1994 from eight stations (one of them is a marine station) by trammel nets. The ages were determined using by scales anda ge composition varied form 0 to 6 ages. Species composition of 1159 sampled individuals were proportionally determined as Mugil cephalus 45%, Liza aurata 35%, Liza saliens 14%, Liza ramada 12%, Chelon labrasus 6%. The growth performance indices calculated from von Bertalanffy growth parameters using by all individuals for the M. cephalus, L. aurata, L. saliens, L. ramada and C. labrasus were determined as 2.957, 2.866, 2.692 and 2.719, respectively. The highest growth performance index was calculated for M. cephalus. The growth performance indeces of mullet species in Köyceğiz-Dalyan Lagoon Ecosystem were found around the world averages.

Cryopreservation and Its Application in Aquaculture

Aquaculture is the major aquatic animal production segment. Problems like inbreeding depression, genetic drift, introgressive hybridization, etc. have been influencing the production of quality seeds negatively. Cryopreservation serves as a way-out for these problems and a possible answer to produce quality seeds and genetically improved varieties. It has been considered as a major strategy for conservation of fish genetic resources. Cryopreservation of fish gametes has been in vogue since 1953 and the technology is well studied and validated for many species. So far the milt of 200 fish species has been cryopreserved successfully. In this chapter, the importance of aquaculture in overcoming malnutrition, genetic issues affecting quality seed production, cryopreservation protocol employed for various fish species, problems faced in cryopreserving fish eggs and embryos and future of cryopreservation in aquaculture have been discussed.