Journal of Fisheries Science

Fillet Quality and Gut Content Analysis of Parachanna obscura and Clarias agboyiensis

Igejongbo Toyosi Fadekemi — 2022-04-28

Nigeria waters are rich with a variety of fish species but only very few are cultured and available for consumption. This study was conducted to know the fillet quality, gut content and condition of Parachanna obscura and Clarias agboyiensis in Nigeria using Igbokoda river as a reference because it is a the major fishing site in the nation. Studies were conducted on the viscera somatic index based on the organ weight and the body weight of the fish and the food item consumed by Parachanna obscura and Clarias agboyiensis between May to October, 2019 to infer on the fillet quality and gut content of P. obscura and C. agboyiensis in the water body respectively. A summary of food items that constituted the diet of Clarias agboyiensis are Baccillariophyta, fish, fat droplets, dinoflagellate, insect and Chlorophyta which constituted the most important food items both occurring in all stomachs containing food. The fishes has more muscle than the viscera organs which indicate that the weight of the fish before dressing out is higher than the weight of the fish after dressing out. This is suggestive of a good quality of food fish. There was a significant correlation between body weight and total length of specimens found in this study. Increases in total length resulted in corresponding increases in body weight. The result for the condition factor showed was below the expected or standard value (K = 1) which shows this species was not in favorable environmental condition. It is therefore necessary to allow phytoplanktons grow well in water body to increase availability of food items to Parachanna obscura and Clarias agboyiensis. P. obscura and C. agboyiensis are also good food fishes of a high fillet quality. They are omnivorous feeders therefore having potentials for aquaculture.

Isolation and Identification of Bacteria found in the milt of cultured Clarias gariepinus

Gabriel Olarinde Mekuleyi — 2022-05-18

Bacteria identification in fish is important; hence it provides update information on emerging and existing organisms thereby enriching the gene bank on fish disease. This study investigated bacteria associated with milt in cultured samples of African catfish- Clarias gariepinus. Catfish broodstock were collected from private Fish Farm in Ogun State, Nigeria. Fish samples were taken to the Microbiology laboratory, Federal University of Agriculture, Abeokuta Ogun State for milt microbial analyses, and amplicon were taken to International Institute of Tropical Agriculture, Ibadan for molecular characterization. Bio-edit was use for importing and mining nucleotide sequences into gene bank. The results revealed that the following bacterial organisms were present in the milt of Clarias gariepinus: Aeromonas caviae, Proteus mirabilis, Serratia rubidaea, Pseudomonas mosselii, Acinetobacter soli and Klebsiella variicola. The Basic Local Alignment Search Tools revealed the percentage similarity ranging from 86- 97.04% and their accession numbers. These bacteria indicated high levels of faecal contamination in the environment. In conclusion, bacteria were found in the milt of cultured catfish and are capable of being pathogenic to humans and may increase the vertical transfer to fry during breeding and rearing stage.

Effects of Dietary Replacement of Maize with Sweet Potato Peel in the Diet of African Catfish Clarias gariepinus (Burchell, 1822)

Abdurrazzaq Ibrahim Abdullahi — 2022-06-28

This study was carried out to evaluate the effects of dietary replacement of maize with sweet potato peel in the diet of Clarias gariepinus juveniles. The levels of the SPP inclusion in the experimental diets were 0%, 25%, 50%, 75% and 100%. All the diets were iso-nitrogenous. One hundred and fifty (150) C. gariepinus juveniles (33 g ~ 35 g) were randomly distributed to five treatments with three replicates each and 5% of their body weight for 12 weeks. Fish carcass proximate compositions analyzed before and after feeding with the experimental diets shows that CP and EE differed significantly (p<0.05) among the experimental fish and the control, except the percentage CP of the fish fed SPP0% and SPP50% in which there was no significant difference (p>0.05). Highest MWG of 207.70±25.95 g was obtained in the fish fed SPP100% followed by 191.30±16.15 g obtained in the fish fed SPP75%. The least MWG of 149.83±16.01 g was recorded in fish fed SPP25%. The highest FCR of 3.61±0.45 g was recorded in the fish fed SPP100%. A steady decrease in FCR was observed with decreasing inclusion levels of SPP meal. However, higher FW, FL, SGR and PER were observed in the experimental fish as from 50% inclusion levels of the SPP. The cost of feed per kg was reduced and the NP and WG increased with increasing levels of SPP and the profitability was enhanced at 100% SPP inclusion level. The results revealed that C. gariepinus juvenile could tolerate up to 50%, 75% and 100% inclusion levels of SPP. The best growth performance was recorded in the fish fed SPP100%, therefore, sweet potato peel can replace maize in the diet of C. gariepinus without any inauspicious effect on the growth performance and nutrient utilization.

Aspects of Impacts of Proposed Badagry Deep Sea Port on the Ecosystem and Livelihood of Fishing Communities in Badagry, Lagos State, Nigeria

Martins A. Anetekhai — 2022-08-11

Federal government of Nigeria, in collaboration with Lagos State Government proposed development of a seaport in Badagry. This research examined and documented the current state of the ecosystem and livelihood of thirteen communities that will be impacted by the proposed deep-sea port. Qualitative and quantitative approaches were used for the study. Review of secondary data was used to investigate the demographic data of the community while Participatory Rural Appraisal was conducted for 300 households in the communities. Majority of the sampled respondents were in the age range of 45 years and above with females (60%) more than males (40%) in the entire population sampled. Educational levels of the respondents are relatively low. The majority of the sampled households have multiple livelihood systems that keep them engaged throughout all seasons of the year. Capture fisheries is the major occupation in the study area and it is complemented with aquaculture. Existing groups are not strong enough to operate as a pressure group to influence policies and regulate market prices, which has been identified as a major limitation in the study area. There was no regular training or capacity building. Hence the groups were not operating as a business enterprise and could not expand or increase capacity. Consequently not able to contribute significantly to poverty alleviation and increase employment opportunities in their localities. This document will serve as one of the guides to the government for decision-making and compensation to the communities.

Ecosystem Restoration: Enhancing Ecosystem Services with Floating Aquaculture

Daniel Rittschof — 2022-09-23

Restoration ecologists recognize the need for restoring ecosystem services in sustainable ways that meet societal needs. In the UK, Ireland, Australia, and some US states the goal is restoring native oyster reefs. In other states, failures at restoration due to poor water quality and predation have focused restoration activities on techniques that work, restoring intertidal reefs and generating living shorelines that reduce or reverse erosion. In the United States, restoring water quality and reducing or reversing erosion are societally accepted entry points for repairing estuarine ecosystems. This study is an overview of the current status of oyster reef restoration and provide a novel approach called “oyster reef in a bag”. Combining oyster reef restoration efforts with existing floating oyster aquaculture technology generates novel ecosystems that are a combination of biofouling and oyster reef communities. These novel ecosystems could be a practical beginning to improve water quality, mitigate erosion and restore higher trophic level ecosystem services.