WATER QUALITY AND ALGAL DIVERSITY OF FISH PONDS AND DAM RESERVOIR IN GESEDADDO FARMS YOLA ADAMAWA STATE NIGERIA

ABSTRACT

The water  quality  and  algal diversity of the  stocked  and  unstocked  ponds and  the  dam reservoir at Gesedaddo farms, Yola, Adamawa State, Nigeria, were assessed for ten months. Meteorological data were accessed from Modibbo Adama University of Technology, Yola. Physico-chemical parameters such as temperature, pH, transparency, conductivity dissolved oxygen,  total  dissolved  solids  (TDS),biochemical   oxygen  demand  (BOD),  magnesium, potassium, sodium, nitrates, sulphates, phosphates,and some trace elements (iron, copper, and zinc) were determined using standard methods.Thedrop count method was employed in algal microscopy.  Algal  diversityand  species  richness  were  determined  using  Margarlef  and Shannon-Wiener indices. A total of forty algal taxa belonging to four divisions were found. They  are  Cyanophyta   (26.47%),  Chlorophyta  (44.53%),  Bacillariophyta   (24.80%)  and Euglenophyta  (4.20%).  All  data  were  subjected  to  statistical  analysis  using  Analysis  of variance ANOVA, Duncan Multiple Range Test DMRT and Correlation coefficient. Tests of significance  were done at P < 0.05  and P < 0.01  confidence  levels. Water  temperatures correlated  positively  with  air  temperatures,  PO4,  NO3,  Fe,  Na  and  Cu.  Total  hardness correlated  negatively  with  pH,  K,  Mn  and  Zn.  Air  and  water  temperatures  correlated positively  with  Navicula  and  Nitzschia  spp.  and  negatively  with  Eudorina  elegans  and Trachelomonas spp.Seasonal variation of algal population revealed that Microcystis species a toxin producing blue-green alga was not recorded  in wet season but were recorded in dry season. However, Micrasterias anindicator of clean water was recorded in the un-stocked fish pond. Phacus, Euglena, and Trachelomonas, indicators of organically polluted environment were recorded in dry season in the fish ponds but absent in dry season in the dam reservoir. The seasonal presence and absence of algal species in particular locations with the ambient physico-chemical parameters make them potential bioindicators for biomonitoring of the fish ponds.  Anthropogenic   activities  in  the  catchment  area  affected  the  concentrations  of chemicals  in the  dam  reservoir  and stocked  fish pond. Chlorophycean  indices were 0.96,

0.873  and  1.57  for  the  stocked  fish  pond,  unstocked  fish  pond  and  the  dam  reservoir respectively, while the Myxophycean indices were 1.0, 0.839 and 1.80for the three locations respectively.These  values suggest that fish ponds were oligotrophic and  the dam reservoir eutrophic.  The study recommends  qualitative  and quantitative  studies  of water quality forearly signals of pollution for timely intervention

CHAPTER ONE

INTRODUCTION

Pond  water  is  considered  as  one  of  the  major  sources  of  water  for  fisheries (Ekpenyong and Adeniyi, 1996; Mustapha, 2006; Chowdhury and Almamun,  2006). Pond fishery  is  practiced  in  the  north-eastern  part  of  Nigeria  on  a  large  scale  for  better augmentation of fish products and hence makes an interesting biotope for physico-chemical and biological studies.

The anthropogenic  inputs of complex mixtures from neighboring communities  and agricultural wastes, such as runoff of manures and fertilizers could lead to alteration of water quality  (Mustapha,  2006;  Garget  al.,  2009).  Of  primary  concern  of  these  anthropogenic activities is their effects on the water quality and aquatic life, hence water quality monitoring is  of  immense  importance  in  the  use  of  water  bodies  for  the  management  of  fisheries (Mustapha, 2006; Nweze, 2009a).

The practice of using cow dungand inorganic fertilizers to encourage algal growth in fish ponds is wide spread in pisciculture in Nigeria (Nweze, 2009b). The algae serve as food for zooplankton, fish fry, benthic vertebrate and other primary consumers that serve as food for fish (Ezenwaji,  2004). Excess  nutrients cause the water body to  become choked  with organic substances exceeding the capacity of micro-organisms that recycle them. It ultimately leads  to  eutrophication  and  encourages  rapid  growth  or  blooms  of  algae  (Chukwu  and Odunze, 2006; Okebukola and Akpan, 2008; Akanet al., 2010).

Phytoplankton  are of great  ecological  significance,  since they comprise  the  major portion of primary producers in the aquatic environment (Nweze,2003;Barinova  et al.,2008, Bellinger and Sigee, 2010). Human activities such as pond fertilization, fertilizers, pesticides and  herbicides  application  as  cultural  practices  of  farm  management;obnoxious  fishing practices, effluent discharges, washing and bathing with detergent and soda soaps stimulate growth of algae.Some of these are thecommonest sources of human-induced water pollution

that bring about eutrophication, hypoxia, fish kill, disruption of food web and changes in the community ecosystem  (Mustapha,  2002, 2006; Krantz and Kifferstein,  2005; Garg  et al.,

2006a, Chia et al., 2011a).

Algae can equally be harmful as some species aretoxins producing, in particular the genera   Microcystis,Oscillatoria,Aphanizomenon   and   Anabaena    which   cause    serious problemsin aquaculture (Nweze 2009b). Some harmful algae in Nigerian waters  had been discussed byKadiri (2000).

Man is currently harnessing phytoplankton forms for augmentation of food supply in fish  ponds,  nitrogen  fixation  in  rice  growing,  pharmaceuticals,  direct  in  food  and  food supplement,  bioremediation  and biomonitoring  (USEPA, 1976;  Borowitzka,  1995; Nweze,

2009a,  andb;  Kadiri,  2010).  Knowledge  of  the  algal  diversity  of  the  Nigerian  aquatic environment is pertinent to meeting up of such demands.

Phycological  information  on Nigerian  lotic and lentic  systems  is still scarce.  The study  of  phytoplankton  distribution  in  the  Nigerian  environmenthas  been  hindered  by taxonomic difficulties,  and more importantly,  inadequate  facilities for the  relevant  studies (Ekpenyong and Adeniyi, 1996; Opute, 2003; Kadiri, 2007).Despite these challenges, there is the need to track the trends that threaten our aquatic ecosystems, specifically pond habitats, and assess the influence  of physico-chemical  parameters  on  the algal diversity for stable aquatic ecosystem.

1.1      AIM AND OBJECTIVES OF THE STUDY

The aims and objectives of the study are to access and determine the water quality and algal diversity of fish ponds and Dam reservoir in Gesedaddo farms, Yola, Nigeria.

The specific objectives are to:

      Assess  the water  quality (physico-chemical  parameters)  of Gesedaddo  farm’s  fish ponds (stocked and unstocked) and dam reservoir;

    Identify the algae present in the ponds and dam reservoir;

    Determine the influence of season on algal diversity in the ponds and dam reservoir.

    Identify indicators for monitoring the water quality of the ponds and dam reservoir;

      Correlate the physico-chemical parameters with algal population of the various ponds and dam reservoir;

    Determine the trophic status of the ponds and the dam reservoir.     Compare flora and physico-chemical (water quality) of the three locations.

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