Multivariate analysis of abundance and distribution of fish species in coast of Ghana, West Africa

Abstract

Marine fishes are currently experiencing population decline which has severe repercussions on food security, especially in fishing households. However, without assessing the distribution and abundance of these marine fishes, ensuring sustainable management will become impossible. Therefore, the study aimed at applying multivariate techniques to determine the biodiversity of fishes along the coast of Ahanta West, Ghana. Fish samples were collected daily through experimental fishing from November-December, 2011. Data obtained from the study were analyzed for ecological indices, species diversity, and community structure using PAST and PRIMER v6 software. From the results, Pteroscion peli (19.2%), Galeoides decadactylus (11.7%), and Brachydeuterus auritus (9.0%) were the dominant fishes. Multivariate analysis identified three main assemblages of fishes, at 18%. For the ecological indices, the species dominance index (SDI) ranged from 0.89 to 0.93, which indicated that the fish species were highly dominated by a few species. The Shannon Weiner index (SWI) and Species Richness index (SRI) spanned between 2.64 – 2.92 and 4.43 – 648 respectively, showing high diversity of fish species. It is concluded that the marine environment along the Ahanta West, Ghana is rich in fish species diversity, and hence, there is the need to regulate existing fishing operations for sustainable utilization and conservation of these commercially important fish species.
 Res. Agric., Livest. Fish.9(1): 57-59, April 2022

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“…The mean of the 'D' reported by [33] was 0.04 which was lower than the mean of the 'D' obtained from the current study. Habitats with more interference, tend to have high 'D' (> 0.6), consisting of only one or a few species, and relatively large populations [22]. In this survey, the mean of the 'D' from the current study was 0.4 indicating a relatively stable habitat with less interference hence the composition of dominant species is relatively balanced and not dominated by only one (1) or two (2) particular species.…”

“…Based on the aforementioned studies findings from the current study were similar to that reported in other works. The reasons for the variation in findings in comparison to other studies could be a result of the following factors, environmental factors, time of sampling, sampling duration, depth and type of fishing gear, biological activities of fish species, geographical location, the possibility of tear of fishing gears and the intensity of fishing activities [22]. Concerning the environmental factors, [23] stated that human impact, however, has become a driving force in shaping the spatiotemporal patterns of species abundance and distribution through direct and indirect effects of fishing exploitation, climate change.…”

“…The Species diversity index (D) refers to its relative importance in its habitat which determines the degree of influence of the species on the ecosystem [22]. The 'D' obtained from the current study ranged from 0.3 to 0.7. and with a mean of 0.4.…”

“…The reason for the monthly variation among the various diversity composition could be both the major and minor upwelling season and the aftermath of the close season that was in July and August. Also, migrating pattern of fishes, the difference in sampling period, type of fishing gear could serve as potential factors [22,35]. Amponsah et al [22] noted that the variation in species diversity resides in the level of nutrients influx from the coastal lagoon linking each of these marine environments and can be attributed to the linkage of the marine environment and coastal lagoon systems which ensures the exchanges between fresh and marine waters.…”

“…Also, migrating pattern of fishes, the difference in sampling period, type of fishing gear could serve as potential factors [22,35]. Amponsah et al [22] noted that the variation in species diversity resides in the level of nutrients influx from the coastal lagoon linking each of these marine environments and can be attributed to the linkage of the marine environment and coastal lagoon systems which ensures the exchanges between fresh and marine waters. Tavares and Arocha [30] observed that the highest diversity levels are likely related to the oceanographic factors associated with high marine productivity and the most important factors are the seasonal upwelling.…”