Advances in Aquaculture and Fisheries Management

Advances in Aquaculture and Fisheries Management ISSN 2756-3278 Vol. 12 (4), pp. 001-011, April, 2024. Available online at www.internationalscholarsjournals.org © International Scholars Journals

Full Length Research Paper

Effects of improved water flow on the aquatic environment and wastewater composition in sewage-fed fisheries of India

Pankaj Kumar Roy*, Arunabha Majumder, Asis Mazumdar, Mrinmoy Majumder and Malabika Biswas Roy

School of Water Resources Engineering, Jadavpur University, Kolkata-700 032, India.

Accepted 30 May, 2023

Abstract

In this study, we estimated the impact of enhanced flow on shallow wetlands that receive major effluent discharge from an adjoining metropolitan city. The local people use the shallow wetlands for pisciculture. Beginning in 1998, the population of the city began to rise and the amount of effluent discharge increased. The excess load is now a problem for the city engineers, and they plan to manage the sewage by increasing the area of the sewage network. The depth of the wetlands is also decreasing due to an increase in suspended solids. The quantity of the toxic load suspended in the discharge has increased the silt content, which has consequently further reduced the depth of the wetlands. The excess flow on low depth wetlands may cause overflows and destroy both the ecosystem and the livelihood of the local people. In this study, the pattern identification capability of neuro-genetic models was used to estimate the impact of the excess flow on sewage-fed wetlands. Two neural network models were created to estimate whether fisheries can accommodate the enhanced flow. According to the results of this study, the East Kolkata Wetlands, India can accommodate 1450 million litres per day (MLD) of sewage, if the average depth of water is increased to 1.18 m.

Keywords: Dry weather flow, East Kolkata wetlands, neural network, sewage-fed fisheries.

Advances in Aquaculture and Fisheries Management ISSN 2756-3278 Vol. 12 (3), pp. 001-012, March, 2024. Available online at www.internationalscholarsjournals.org © International Scholars Journals

Full Length Research Paper

Age, growth, and management of tilapia zilli (Gerv, 1848) in Lake Timsah: A comprehensive study

Waheed Farg-Alla Mahomoud¹, Amal Mohamed Mahmoud Amin², Kamal Fathey Elboray¹ Amal Mohamed Ramadan and Magdy Mostafa Kamal Osman EL-Halfawy¹*

¹Fish Reproduction and Induced spawning Laboratory, Aquaculture Division, National Institute of Oceanography and
Fisheries, Suez, Egypt.
²Stock Assessment Laboratory, Fisheries Division, National Institute of Oceanography and Fisheries, Suez, Egypt.

Accepted 2 December, 2023

Abstract

In the present investigation, some biological aspects of Tilapia zillii from Lake Timsah were studied. This was carried out on 700 fish samples collected during the period from October, 2002 to September, 2003. Total length of females ranged from 7 to 16 cm and males from 8 to 21cm. Age determination based on length frequency distributions showed that the life span are two and four years for females and males, respectively. Estimates of growth parameters are widely used for detailed assessment and modeling of fish species and fisheries. The length-weight relationship, age at length zero (to), growth coefficient (K), asymptotic length (L∞) and rates of natural (M) and total mortality (Z) were estimated for T. zillii from Lake Timsah. Length-weight relationships were calculated from individual fish length and weight records collected from sampling using gill nets. Analyses were obtained by sampling direct from the fisher’s catches. Data were analyzed using the FISAT software. T. zillii, the estimate of K was 0.320 and 0.680 year-1 for males and females, respectively, whilst L∞ was approximately 22.05 and 17.85 cm, for males and females, respectively. T. zillii (males) had the lowest value of K and the largest L∞ than females. Natural mortality was the lowest for T. zillii (females) (M=0.464 and 0.38 year-1) and fishing mortality was highest for T. zillii (males) (F=2.656, 1.88 year-1). In addition, exploitation rate was estimated at E=0.83 and length at first capture (Lc) was calculated at 11.30 cm for males while E=0.78 and (Lc) was estimated as 6.68 cm for females. The majority of fish caught of the main commercial species in the Lake Timsah fishery were from the first age group, at a size far below the optimal length at capture. This suggests growth overfishing for T. zillii in Lake Timsah.

Key words: Lake Timsah, Tilapia zillii, age and growth, mortality, gonadosomatic index, length at first maturity, population structure.

Advances in Aquaculture and Fisheries Management ISSN 2756-3278 Vol. 12 (2), pp. 001-008, February, 2024. Available online at www.internationalscholarsjournals.org © International Scholars Journals

Full Length Research Paper

Ecological insights into the Frillfin Goby in Badagry Creek, Lagos, Nigeria

O. Lawson Emmanuel* and E. Thomas Ajibola

Department of Fisheries, Faculty of Science, Lagos State University, Ojo P. O. Box 0001, LASU Post Office, Lagos, Nigeria.

Accepted 25 October, 2023

Abstract

A study was conducted in Badagry Creek in Lagos, Nigeria on food and feeding habits and reproduction of Frillfin goby (Bathygobius soporator). Data collected from the study intend to serve as a baseline for carrying out further study on the fishes and fisheries of this water body. B. soporator is one of the numerous and diverse fishes of the family Gobiidae which share certain similarities in their life histories. Gobies are among the most successful fishes. They are resident intertidal species which could be found in pools, rocky pools, lagoons, creeks and estuaries. Specimens were collected from the Badagry Creek via Oto-Awori Fish Jetty between January, 2008 and January, 2009. Foods and feeding habits and reproduction were studied in this creek. Seven groups of food items were encountered in the stomachs of the fish, viz; Crustaceans, Pisces, Insects, Detritus, Bivalves, unidentified food materials and Gastropods. The most eaten of these were the crustaceans contributing 34% by number and 38.30% by frequency of occurrence. The presence of other fish species in the stomachs explained the piscivorous habit while the unidentified food materials demonstrate its herbivorous character. Its predatory and carnivorous tendency was exhibited by the presence of insects, bivalves, crustaceans, and gastropods. Presence of sand grains was an indicator of its benthic nature. The specimens were classified as either male or female. Four hundred and seventy and five specimens representing 98.95 and 1.05% of total catch were classified as males and females, respectively giving 1 (male): 0.01 (female) sex ratio. This is significantly different (P>0.05) from the expected or theoretical one male:one female ratio and not in conformity with sex ratios that were reported for some fishes in the adjacent Ologe, Lagos, Lekki and Epe lagoons which favoured more females. The Gonadosomatic index (GSI) of this species varied from 0.00 to 2.89%, meaning less than 2.89% of the fish’s body mass was converted to gonads for reproduction. The pre-spawning and spawning stages of this species contributed 86.75 and 13.25% of the specimens, respectively. Post spawning stages were absent.

Key words: Gonadosomatic index, spawning, Ologe, Badagry, Lekki, Epe.

Advances in Aquaculture and Fisheries Management ISSN 2756-3278 Vol. 12 (1), pp. 001-013, January, 2024. © International Scholars Journals

Review

Exploring the Integration of Coastal and Marine Areas into Sustainable Development Strategies: Lessons from Africa

Eric O. Odada

Department of Earth Sciences, Marine Geology and Oceanography Unit, University of Nairob, P. O. Box 30197-00100 Nairobi, Kenya. E-mail: [email protected].

Accepted 17 August, 2023

Abstract

The coastal and marine environments of the African region are uniquely situated to support a variety of activities and to serve diverse human needs for food, transport, and recreation. The pressures from growing populations in coastal zones of Africa, expanding coastal tourism, intensified fisheries, and a large number of other economic activities pose an increasing threat, which jeopardize the quality of these coastal and marine environments. Large-scale destruction of some of Africa’s most valuable resources, the coastal forests and mangroves, the lagoons and coral reefs has caused serious degradation of the environment, thus affecting the life of the coastal inhabitants and the economic development of the countries of the African region. The Seychelles Island in the western Indian Ocean for example, was famous for its luxuriant forests and an incredible abundance of wildlife. But many reefs have been mined for coral for the purpose of construction. Mangrove forests on the granitic islands have been raised to the ground or drained and reclaimed. Severe erosion is as a result of this destruction. Many African countries are confronted with serious manpower problems, which are proving to be great impediments in the economic development, especially of their coastal and marine areas. In many cases, the most important cause underlying these problems is the lack of adequate training facilities for the type of manpower required. The teaching of marine science and marine technology in universities of the region is a recent development and in many of the universities, there are as yet no comprehensive study programmes covering the whole spectrum of marine science and technology at the undergraduate or postgraduate level. The situation in regard to research in marine science and technology is equally unsatisfactory. To implement sustainable development of coastal and marine resources of the African region, there is an urgent need to: (1) build human resources by undertaking short-term academic training to strengthen existing capabilities; (2) promote public awareness by producing educational materials on the ecological and socio-conomic contributions of the marine resources and the consequences of unsustainable exploitation (3) organise policy workshops, seminar and/or conferences involving relevant policy and law-makers to increase their understanding of and commitment to the sustainable use of the resources in their coastal and marine areas, and (4) implement integrated coastal zone management programmes by establishing case studies in pilot sites in selected countries of the African region. The object of this paper is to review background information on the present status and trends of coastal and ocean development in Africa, and on the existing capabilities in the region to implement sustainable development strategies. It is intended to lay out the framework and strategy to be used in the design of an integrated management of coastal and marine areas in the region.

Key words: Coastal ecosystems, marine environments, sustainable development, population pressure, environmental degradation, sea level rise, capacity building, management planning.

Advances in Aquaculture and Fisheries Management ISSN 2756-3278 Vol. 12 (1), pp. 001-007, January, 2024. © International Scholars Journals

Full Length Research Paper

An In-depth Study on the Impact of Inland Fisheries Decree on Sustainable Exploitation of Inland Fisheries in Lagos State, Nigeria

Enaikele M. D.¹* and Olutayo A. O²

¹Department of General Studies, Federal College of Fisheries and Marine Technology, Lagos, Nigeria.

²Department of Sociology, University of Ibadan, Ibadan, Nigeria.

Accepted 13 August, 2023

Abstract

To achieve sustainable and socially beneficial exploitation of the fishery resources led to the promulgation of the Inland Fisheries Decree 108 of 1992. The objective of this study was focused on whether the inland fisheries decree has significantly curbed the various threats to inland fishery stocks and the development of artisanal fishery Four communities (Ibeshe, Iyagbe, Agbowa-Ikosi and Ebute-Afuye) in Lagos State were purposively selected. With the aid of simple random sampling, 309 fisher folks were interviewed. Thirty (30) fisher folks were arranged for FGDs in each of the communities and group discussants were stratified into adult men, women and youths. The key informants interviewed were traditional rulers and the head of fisher folks. Data was analysed using descriptive statistic and Pearson Chi-square. The results reveal that with the level of significant (0.05) the null hypothesis was rejected. The study concludes that the fisher folks’ perception of the fisheries decree is significantly related to conformity with the decree. The provisions of the decree did not exhaust the register of threats to artisanal fishery. The decree did not address the problem of pollution and open access regime in artisanal fishery. The decree is grossly violated by the artisanal fisher folks. They use small mesh nets and unorthodox (plant derived poison) fishing methods. The reasons for the violation of the decree were: penalties for violation are too cheap to have any impact; and poor monitoring and enforcement of the decree. The study recommends that government should invest the authority to manage and control the exploitation of fishery resources on the artisanal fisher folks. The decree should be reviewed and be well enforced. Such review should accommodate wider consultation of fishery experts, as well as participatory in-puts, mobilization and sensitization of artisanal fisher folks.

Key words: Explorative analysis, inland fisheries decree, artisanal fishery sector.

Advances in Aquaculture and Fisheries Management ISSN 2756-3278 Vol. 11 (3), pp. 001-005, March, 2023. © International Scholars Journals

Full Length Research Paper

Length-weight relationships for 13 fish species from the Gulf of Gabes (Southern Tunisia, Central Mediterranean)

Hajjej Ghailen¹, Hattour Abdallah¹, Allaya Hassan², Cherif Mourad¹, Bouain Abderrahmen³ and Jarboui Othman¹

¹National Institute of Marine Sciences and Technologies (I.N.S.T.M), 3018 Sfax, Tunisia.

²Faculty of Sciences of Tunis, University Campus, 2092 El Manar Tunis, Tunisia.

³Faculty of Sciences of Sfax, Soukra Road km 4 - BP n ° 802 - 3038 Sfax, Tunisia.

Accepted 5 November, 2022

Abstract

Length-weight relationships (LWR) were estimated for 13 fish species which are of economic relevance in the commercial fisheries of the Gulf of Gabes (southern Tunisia). A total of 2403 fish specimens were sampled with several fishing gears from October 2008 to September 2009. The sample size ranged from 65 individuals for Coryphaena hippurus to 346 for Euthynnus alletteratus. The b values in the LWR, W = aL^b ranged from 2.807 to 3.284, with a mean of 3.015 ± 0.102 and intercepts between 0.0011 and 0.0432 with a mean of 0.0139. The condition factor (c.f.) values significantly (p < 0.05) ranged from 0.64 to 1.55.

Key words: Gulf of Gabes, length-weight, fish species, condition factor.