Browsing by Author "Rumisha, Cyrus"

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DNA barcoding reveals endangered and protected elasmobranchs in Tanzanian fish markets
(Western Indian Ocean Journal of Marine Science, 2023) Rumisha, Cyrus; Simwanza, Rehema J.; Nehemia, Alex; Mdegela, Robinson H.; Kochzius, Marc
Western Indian Ocean countries have banned elasmobranch finning and enacted legislation to of Marine Science 22(1): 57-65protect endangered elasmobranchs, however finned and morphologically deformed specimens [doi: 10.4314/wiojms.v22i1.6]are still landed and traded on Tanzanian fish markets. Such specimens are difficult to identify Received:morphologically, and it is possible that protected elasmobranchs are among these. This study September 19, 2022used DNA barcoding to uncover protected elasmobranchs in 102 specimens traded on Tan- Accepted:zanian fish markets. The sampled specimens revealed 23 elasmobranch species, 12 of which April 04, 2023(52.1 %) were classified as endangered (EN) or critically endangered (CR) on the IUCN Red List. Published:Three of the identified species (great hammerhead Sphyrna mokarran, oceanic whitetip shark June 16, 2023Carcharhinus longimanus, and pelagic thresher Alopias pelagicus) are protected by Tanzanian laws. Copyright:Hence, it is advised that steps be taken to strengthen law enforcement at landing sites and fish Owned by the journal.markets in the country. Furthermore, the Third Schedule of Fisheries (Amendment) Regula- The articles are open accesstions of 2009 should be updated to include 11 EN and CR elasmobranchs that are not on the list. articles distributed underAdditionally, national and regional elasmobranch conservation plans should be developed to the terms and conditions of the Creative Commons Attribution (CC BY 4.0) licence. prevent the exploitation of endangered elasmobranchs.
Effect of soybean and seaweed-based diets on growth performance, feed utilization, and gut microbiota of tilapia: a systematic review and meta-analysis
(PLOS ONE, 2024-07-24) Viagem, Leonildo dos Anjo; Hakizimana, Jean Nepomuscene; Rumisha, Cyrus; Cerozi, Brunno da Silva; Misinzo, Gerald
Tilapia, a significant aquaculture species globally, relies heavily on feed for its production. While numerous studies have investigated the impact of soybean and seaweed-based diets on tilapia, a comprehensive understanding remains elusive. This review aimed at evaluating and synthesizing the existing literature on these diets’ effects, focusing on growth perfor- mance, feed utilization, and gut microbiota. A systematic search of databases was con- ducted using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and a total of 57 studies were included in the qualitative analysis and 24 in the meta-analysis. The results indicated that soybean-based diets, at a 59.4% inclu- sion level improved the Specific Growth Rate (SGR) of tilapia with an effect size of -2.14 (95% CI: -2.92, -1.37; p < 0.00001; I 2 = 99%) and did not improve the feed conversion rate (FCR), as the effect size was 1.80 (95% CI: 0.72, 2.89; p = 0.001; I 2 = 100%). For seaweed- based diets, at a 15,9% inclusion level did not improve SGR, with an effect size of -0.74 (95% CI: -1.70, 0.22; p = 0.13; I 2 = 99%), and the FCR with an effect size of -0.70 (95% CI: -1.94, 0.54; p = 0.27; I 2 = 100%). Regarding the gut microbiota, was noted a lack of studies meeting the inclusion criteria for tilapia. However, findings from studies on other farmed fishes suggested that soybean and seaweed-based diets could have diverse effects on gut microbiota composition and promote the growth of beneficial microbiota. This study sug- gests that incorporating soybean-based diets at 59.4% inclusion can improve the SGR of tilapia. Seaweed-based diets, while not demonstrating improvement in the analyzed param- eters with an inclusion level of 15.9%, have the potential to contribute to the sustainability of the aquaculture industry when incorporated at lower levels.
Field and DNA-barcode based surveys reveal evidence of rare endemic fishes in the Rufiji River Basin
(PLOS ONE, 2024-09-19) Saiperaki, Jackson L.; Materu, Silvia F.; Mkenda, Prisila A.; Ligate, Elly J.; Rumisha, Cyrus
Endemic fish species have long supported the livelihoods of local communities in the Rufiji River Basin (RRB). However, destructive fishing practices have led to a concerning decline in endemic fish stocks. To assess these changes, this study employed key informant inter- views, focus group discussions (FGDs), and fishery surveys to assess the historical and contemporary distribution of endemic fishes within the RRB. DNA barcoding was also used to verify species identities. Out of 37 reported fish species, 33 species (54.55% endemic and 45.45% exotic to RRB) were confirmed through DNA barcoding and morphological characteristics. About 5 species including, Heterobranchus longifilis, Citharinus congicus, Labeo congoro, Mormyrus longirostris, and Labeobarbus leleupanus were rarely found in the field, despite being classified as Least Concern by IUCN. Additionally, five species that were reported to be present in the RRB by experienced fishers were not captured during sampling. This highlights the need for validation of the existence of such species through eDNA metabarcoding. Moreover, due to the rarity of some species in the area, their IUCN assessment should be revisited.
Length-Weight relationship and condition factor of tilapia species grown in marine and fresh water ponds
(Agriculture and Biology Journal of North America, 2012) Nehemia, Alex; Maganira, Justin D.; Rumisha, Cyrus
The aim of this study was to describe the differences in Length-Weight relationship and condition factor of Tilapia zillii and Oreochromis urolepis urolepis reared in full strength sea water (FSSW) and fresh water (FW) ponds. The environmental condition in FSSW and FW ponds were also analyzed to determine their impacts on Length-Weight relationship and condition factor on both species. The regression coefficient "b" exhibit negative allometric growth in FW and positive allometric growth in FSSW for both species. The value of exponent "b" and condition factor (K) for T. zillii in FW and FSSW (in the bracket) were found to be 2.94 (3.3) and 2.07 (0.74) respectively. On the other hand the value of exponent "b" and condition factor (K) for O. urolepis urolepis in FW and FSSW (in the bracket) were found to be 2.81 (3.46) and 0.86 (0.53) respectively. Though both species performed well in FW, the study also revelead that farming of these tilapia species in FSSW can be feasible if water quality parameters are properly monitored.
Low genetic diversity and lack of genetic structure among populations of the sandfish holothuria (metriatyla) scabra on the Tanzanian coast
(Taylor & Francis Group, 2023-02-27) Bugota, Valeli J.; Rumisha, Cyrus
The tropical sandfish Holothuria (Metriatyla) scabra Jaeger, 1833 has been severely depleted in the Western Indian Ocean because it is easy to catch and in high demand. In response, Mainland Tanzania closed the fishery; however, the fishery remains open in the semi- autonomous islands of Zanzibar. Yet, it is unknown whether the aforementioned contrasting management measures are consistent with the genetic stock structure of the fishery. Therefore, this study analysed partial sequences (706 base pairs) of the cytochrome oxidase subunit I gene (COI) from four sandfish populations from Tanzania to assess the extent of genetic diversity and population structure. The populations showed low haplotype (0.17– 0.44) and nucleotide diversities (0.025–0.084%), as well as small mutation-scaled effective size (9 × 10 −4 −17 × 10 −4 ) compared to other marine macroinvertebrates from Tanzania, suggesting that the fishery has not recovered despite the ban that was imposed 16 years ago. Furthermore, Analysis of Molecular Variance (AMOVA) revealed a low and non- significant genetic differentiation index (F ST = 0.0047, p > 0.05), indicating a lack of population structure. The lack of population structure was further supported by phylogenetic analysis, which grouped together all COI haplotypes of sandfishes from both Zanzibar and Mainland Tanzania. This suggests that populations in Mainland Tanzania and Zanzibar are genetically homogeneous and that Zanzibari fishers may be targeting the same stock that is protected in Mainland Tanzania. Therefore, the fishery should be managed as a single unit and management measures between Mainland Tanzania and Zanzibar should be harmonized.
Status of trace metals and arsenic in sediments and catfish muscles (Clarias gariepinus) from the Eastern Tanzanian basin
(PLOS ONE, 2024-08-29) Mayila, Edward; Mzula, Alexanda; Rumisha, Cyrus; Leermakers, Martine; Huyghe, Filip; Kochzius, Marc
Trace metals and metalloids are groups of chemical elements that naturally occur in low concentrations and cycle in the environment driven by natural processes and human activi- ties. They have a persistent and bio-accumulative tendency in the environment, and certain trace metals and metalloids have become a public health concern. This study assesses the concentration of eleven trace metals and a metalloid in sediments and catfish muscle from five study sites in the Eastern Tanzanian River basin. Forty catfish tissues and fifteen sedi- ment samples were collected and analyzed using ICP-MS. Concentrations of As, Cd, Co, Pb, and Zn did not exceed the United States Environmental Protection Agency (USEPA) guideline for pollution of sediments, while Al Cr, Al, Mn, and V with values ranging from (118.54 to 70154.55) indicating moderately polluted. The stations Java-Sadaani and Matandu showed the highest Cr, Ni, and Cu concentrations, but the potential ecological risk index (RI) was low (RI < 95). In the catfish muscle tissue, the levels of Cd, Pb, Cu, and Zn did not surpass the EU and FAO/WHO limits and results ranged from 2.22 to 35.22mg/kg. Low levels of accumulation of Cd, Pb, and As were found in this study compared to catfish muscles from other studies, whereas the concentrations of other trace metals and metal- loids analyzed had comparable results. Biota/sediment accumulation factors (BSAF) were all < 1. The weekly metal intake (MWI) results ranged from 6.89E-04 to 2.43E+01 μg/know- 1week-1, indicating a low risk as the value did not exceed the FAO/WHO established Per- missible Tolerable Weekly Intake (PTWI). The non-carcinogenic health risk result THQ was 4.43E-02 and the carcinogenic health risks result HI was 4.42E-05 which indicated tolerable levels of risks as both the values of the Target Hazard Quotient (THQ) and the Hazard Index (HI) was < 1, and the carcinogenic target risk (TR) is < 0.0001. The highest TR values were observed for Cr and Ni. We recommend a continued monitoring of the changes in trace metal levels in the environment and biota together with continuous public health education on the dangers of high levels of trace metals.