Journal of Fisheries

Ichthyofauna of Gibe Sheleko National Park and some morphometric relationships of fish of the tributary rivers, Southern Ethiopia

2021-04-26T19:26:41+00:00

Understanding of Ichthyofaunal diversity is a major gateway for the conservation of waterbodies in the world. Ethiopia has a rich Ichthyofaunal diversity, although they are poorly known. This study was carried out in two tributary rivers (Gibe and Wabe) of Gibe Sheleko National Park to investigate Ichthyofaunal diversity and morphometric characteristics of fish. By using monofilament gill-nets, fish were collected, identified and measured their morphometric. A total of 10 species were identified, dominated by Synodontis schall, followed by Labeobarbus nedgia and Labeobarbus intermedius. According to the Index of Relative Importance, S. schall was also first (49.13%), followed by L. intermedius (15.49%). Gibe River had a higher number of species than Wabe River. The Shannon Diversity Index in Gibe River was also higher (2.09) than Wabe (1.84) during the dry season, but lowest in the wet season (1.52 and 1.57 respectively). Synodontis schall had the largest girth, but Clarias gariepinus had the largest eye diameter and body weight. Heterobranchus longifilis was first in total, fork and standard body length. Generally, differences in sampling habitats and fishing effort might have contributed to discovered variants findings. Fishery development should be implemented in the Park to use the fish resource sustainably.

Population structure and shell dimension of the invasive veined whelk (Rapana venosa)

2021-04-26T19:19:23+00:00

The veined whelk (Rapana venosa) is a widely known invasive species in the Black Sea. This species exerts negative impacts on the Black Sea ecosystem including destruction of bivalve, mussel and oyster populations. This study aimed to examine population structure using the length-frequency distribution and shell dimensions of R. venosa, collected from the Black Sea. A total of 506 specimens were collected from the Trabzon Coast and classified into 6 age groups using the Bhattacharya method. The Von-Bertalanffy growth parameters were calculated as L_∞= 10.29 cm, k = 0.09, t₀ = 1.25 yr^–1. The mortality and exploitation rates were estimated as total mortality Z = 0.51 yr^–1, fishing mortality F = 0.31 yr^–1, annual mortality M = 0.20 yr^–1 and exploitation rate E = 0.60 yr^–1. This study will help understanding the growth of R. venosa and its management.

Investigation on the effects of Inula viscosa L. on rainbow trout gonad cells induced by lipopolysaccharide

2021-04-13T00:42:18+00:00

Fish cells have been accepted as an alternative to in vivo assay for inflammatory effects of therapeutic experimental systems. To reveal the anti-inflammatory effects of Inula viscosa (IV) fish cell line RTG-2, derived from the gonadal tissue of rainbow trout, was infected with lipopolysaccharide (LPS). Effective concentrations for different concentrations of LPS (1, 5, 10, 20 µM) and IN (1, 5, 10, 20 µg ml^–1) were determined. While the 20 µM concentration of LPS, which was effectively selected from preliminary tests, caused 27% cell loss, the effective 1 µg ml^–1 concentration of IN caused 1.1% proliferation in the cells when compared to the control group. All pro-inflammatory parameters investigated in LPS-induced RTG-2 cells showed up-regulation, with the highest increase in TNF-α gene expression level (11.3 fold changes). Down-regulation was determined in the IN together with LPS administered group and IL-1β had the highest effect with 96%. IL-6 protein level decreased by LPS at a rate of 4% and IN together with LPS increased by 9%. The IN exhibited significant efficacy against inflammation caused by LPS. However, further studies are needed to determine pharmacological activity of I. viscosa in details.

Quality changes in sea grape, Caulerpa lentillifera at different brine concentrations

2021-04-14T00:45:14+00:00

Sea grapes are among the seaweeds being commercialized in the Philippines. They are sold in fresh state, and are highly perishable. It is necessary to develop preservation techniques in order to lengthen its shelf life. This study aims to assess the physico-chemical, microbial and sensorial quality of sea grape Caulerpa lentillifera preserved in 0%, 5%, 10% and 15% brine concentrations. Results revealed that brining effectively extended the shelf life of C. lentillifera by inhibiting the growth of bacteria and maintaining the osmotic pressure between the product and the solution. Within the 10 days storage period, 10% and 15% were bacteriologically stable and more acceptable upon rehydration. Treatments 0% and 5% were not acceptable because it exceeded the bacterial limit set for fresh vegetables. The sensorial attributes were compromised and became less acceptable due to degradation through bacterial action. In terms of physico-chemical analysis, high salt concentration (15%) decreased chlorophyll and carotenoid content significantly due to shrinkage and water loss. Overall, this study proved that sea grapes in 10% brine solution can extend its shelf life.

Potential use of mud clam (Geloina coaxans) in producing sauce with papaya crude extraction as a protein hydrolysing agent

2021-03-17T22:51:52+00:00

Mud clam (Geloina coaxans) are underutilised food source due to the lack of consumer preference in Sri Lanka. Hence, this study was conducted to produce clam sauce as a value added product using the muscle of mud clams by means of accelerated fermentation method. Specimens were collected from Tambalagam Bay, Sri Lanka. Shell length, height, inflation, total weight with shell and without shell were 6.3 ± 0.4 cm, 5.3 ± 0.3 cm, 3.5 ± 0.3 cm, 83.1 ± 13.4 g and 14.9 ± 1.3 g respectively. The extracted mean meat yield was 14.9 ± 1.3% per mud clam. Moisture, crude protein, crude lipid and ash (dry weight) content of raw meat were 80.45 ± 0.89%, 64.14 ± 0.96%, 3.55 ± 0.39% and 7.54 ± 0.61% respectively. Final sauce product shows liquid yield, energy value, ⁰Brix value, pH, % NaCl, total nitrogen, moisture and ash content as 98.3 ± 5.5 ml 100g^–1, 2124 ± 133 J g^–1, 24.3 ± 0.9%, 5.02 ± 0.04, 14.53 ± 0.27%, 0.27 ± 0.01%, 74.06 ± 0.56% and 19.66 ± 1.99% respectively. The study concluded that the mud clam meat is a possible candidate as a raw material for the production of clam sauce.