• O. O. Oyebola Department of Aquaculture and Fisheries Management, University of Ibadan, Ibadan, Nigeria
  • O. Onadokun Department of Aquaculture and Fisheries Management, University of Ibadan, Ibadan, Nigeria
  • S. O. Ogboye Department of Aquaculture and Fisheries Management, University of Ibadan, Ibadan, Nigeria


Phenotypic structure, Morphologic variability, Croaker fish, Lagoon ecosystems


The adaptive phenotypic flexibility, descriptive and discreteness characteristics of Pseudotolithus typus obtained from Epe and Lagos lagoons in southwestern Nigeria were investigated to ensure precise identification, management and conservation of the species. Six meristic counts and 15 morphometric measurements were collected from mature Pseudotolithus typus obtained from Epe and Lagos Lagoons. Data on phenotypic and heterogeneous attributes were analysed using descriptive statistics, linear regression, and Discriminant Factor Analysis (DFA).  Meristic values ranged from 2.00±0.00 (Eye) - 30.80±1.16 (Dorsal-Fin-Rays) and 2.00±0.00 (Eye) - 31.03±0.76 (Dorsal-Fin-Rays) in Epe and Lagos lagoons, respectively. Dorsal Spine Count had a higher variation at Epe (Coefficient of Variation, CV=5.58%) than Lagos lagoon (CV=4.65%). Morphometric values ranged from 4.25±0.51 (Orbital Length) - 28.77±1.54 (Head Length) in Epe Lagoon; and 3.52±0.22 (Pectoral Fin Width) - 28.35±1.75 (Body Depth) in Lagos Lagoon. Caudal Peduncle Length (CV=34.02%) and Mouth Height (CV= 12.44%) had the highest variation in Epe and Lagos Lagoons; respectively. Generally, 56.25% and 37.50% of the attributes had CV>10% in Epe and Lagos Lagoons. Cross-validation of group membership revealed 95.0% (entire), 93.3% (Epe) and 96.7% (Lagos) correctness of the apriori groupings. Pseudotolithus typus population demonstrated taxonomic sanctity, but differentially flexible phenotypes across Epe and Lagos lagoons. This indicates the adaptive potential and survivability of the species in multiple lagoon environments.


Adjigbe, G. R., Zacharie, S. and Diane, G. K. (2023). Study of the population structure, exploitation level and growth in relation to the otoliths weight of Pseudotolithus senegalensis (Valenciennes, 1833) and Pseudotolithus typus (Bleeker, 1863) in Benin coasts. Research Square. DOI 10.21203/

Anyanwu, A. O. and Kusemiju K. I. (1990). Food of the croakers Pseudotolithus senegalensis (C. & V.) and Pseudotolithus typus (Bleeker) off the coast of Lagos, Nigeria. Journal of Fish Biology 37 (5): 823-825.

Askari, G. H. and Shabani, A. (2013) Genetic diversity evaluation of Paraschistura bampurensis (Nikolskii, 1900) in Shapour and Berim rivers (Iran) using microsatellite markers. Journal of Cell Biology and Genetic 3: 29-34.

Avise, J. C., (1994). Molecular Markers, Natural History and Evolution. Chapman and Hall, New York, London.

Awotunde, O. M. (2021). Stomach and gut content of Long Neck Croacker–Pseudotolithus typus (Bleeker,1863) from Lagos Lagoon, Nigeria. Annals of Marine Science 5(1): 001-006. DOI:

Bachok, Z., Mansor, M. I. and Noordin, R. M. (2004). Diet composition and food habits of demersal and pelagic marine fishes from Terengganu waters, east coast of Peninsular, Malaysia. NAGA WorldFish Center Quarterly 27: 41-43.

Badejo, O. T., Olaleye, J. B., and Alademomi, A. S. (2014). Tidal characteristics and sounding datum variation in Lagos State. International Journal of Innovative Research and Studies. 3(7): 436-457.

Cadrin, S. X. and Friedland, K. D. (1999). The utility of image processing techniques for morphometric analysis and stock identification. Fisheries Research 43: 129 - 139.

DeWitt, T. J. and Scheiner, S. M. (2004). Phenotypic plasticity: functional and conceptual approaches. Oxford University Press, Oxford.

Elliott, N. G., Haskard, K. and Koslow, J. A. (1995). Morphometric analysis of orange roughy (Hoplostethus atlanticus) off the continental slope of southern Australia. Fish Biology 46, (2): 202-220.

Espinosa-Lemus V., Arredondo-Figueroa J. L. and Barriga-Sosa, I. D. L. A. (2009). Caracterización morfometrica y genética de stocks de tilapias (Cichildae:Tilapiini) para un efectivo manejo de sus pesquerías en dos presas mexicanas. Hidrobiológica 19 (2): 95-107.

Forsman, A. (2015). Rethinking phenotypic plasticity and its consequences for individuals, populations and species. Heredity 115, 276–284. doi: 10.1038/hdy.2014.92

Gaffer, J. A. (1994). Fish production and the Nigerian environment, status, opportunities, threats. A keynote address presented at the 11th Annual Conference of Fisheries Society of Nigeria, Lagos 22-24 February 1994.

Ghalambor, C. K., McKay, J. K., Carroll, S. P. and Reznick, D. N., (2007). Adaptive versus non-adaptive phenotypic plasticity and the potential for contemporary adaptation in new environments. Functional Ecology 21 (3); 394-407.

Gunawickrama, K. B. S. (2007). Morphological heterogeneity in some estuarine populations of the Catfish Arius jella (Ariidae) in Sri lanka, Cey Journal of Science (Biological Science) 36(2); 100-107

Jang, Y., Kim, A., Amin, M. H. F., Sapto, A. A., Zuweh Jr. A. and Kim, H. (2021). The complete mitochondrial genome of the longneck croaker, Pseudotolithus typus Bleeker, 1863 from Sierra Leone, Mitochondrial DNA Part B, 6: 5, 1640-1641. DOI: 10.1080/23802359.2021.1927218

Lind, M. I., Yarlett, K., Reger, J., Carter, M. J. and Beckerman, A. P. (2015). The alignment between phenotypic plasticity, the major axis of genetic variation and the response to selection. Proceedings of the Royal Society. B- Biological Sciences 282:20151651

Martín, A. G., Jorge, M. R., Elena, A., Andrés, M., Antón, G., and Francisco, P. (2016). Characterization of morphological and meristic traits and their variations between two different populations (wild and cultured) of Cichlasoma festae, a species native to tropical Ecuadorian rivers. Archives Animal Breeding 59: 435–444.

Mayr, E., (1969). Principles of systematic zoology. New York: McGraw Hill Book Company, 428 pp.

McHenry, M. J. and Lauder, G. V. (2006). Ontogeny of form and function: locomotor morphology and drag in zebrafish (Danio rerio). Journal of Morphology 267: 1099–1109. doi:10.1002/jmor.10462

Njinkoue, J. M. Gouado, I. Tchoumbougnang, F. Yanga Ngueguim, J. H. Ndinteh, D. T. Fomogne-Fodjo, C. Y. and Schweigert, F. J. (2016). Proximate composition, mineral content and fatty acid profile of two marine fishes from Cameroonian coast: Pseudotolithus typus (Bleeker, 1863) and Pseudotolithus elongatus (Bowdich, 1825), Nutrition and Food Science Journal 4: 27-31

Nonaka, E., Svanbäck, R., Thibert-Plante X., Englund, G., and Brännström, A. (2015). Mechanisms by which phenotypic plasticity affects adaptive divergence and ecological speciation. The American Naturalist 186 (5).

Nta, A. I. Akpan, A. W. Okon, A. O. and Esenowo, I. K. (2020). Aspects of the reproductive biology of Pseudotolithus typus (Bleeker, 1863) from qua Iboe River Estuary, Nigeria. Journal of Aquatic Sciences, 35: 1. DOI: 10.4314/jas.v35i1.7

Olopade, O. A. and Dienye, H. E. (2023). Health status of sciaenid species following mass fish kills in coastal waters of Niger Delta, Nigeria. World Journal of Advanced Research and Reviews, 18 (02): 807–813. DOI:

Ossoukpe, E., Nunoo, F. and Dankwa, H. (2013). Population structure and reproductive parameters of the Longneck croaker, Pseudotolithus typus (Pisces, Bleeker, 1863) in nearshore waters of Benin (West Africa) and their implications for management. Agricultural Sciences 4: 9-18. DOI: 10.4236/as.2013.46A002.

Oyebola, O. O. (2015). Phenotypic variability revealed discriminate pectoral spine variants in small population of Clarias gariepinus (Burchell, 1822) of hydrodynamic environment. Nature Science, 13 (3): 96-108.

Peck, M. A., Reglero, P., Takahashi, M. and Catalán, I. A. (2013). Life cycle ecophysiology of small pelagic fish and climate-driven changes in populations. Progress in Oceanography 116, 220–245. DOI: 10.1016/j.pocean.2013.05.012

Robinson, B. W. and Parsons, K. J. (2002). Changing times, spaces, and faces: tests and implications of adaptive morphological plasticity in the fishes of northern postglacial lakes. Canadian Journal of Fisheries and Aquatic Sciences, 59: 1819-1833.

Robinson, B. W. and Dukas, R. (1999). The influence of phenotypic modifications on evolution: the Baldwin effect and modern perspectives. Oikos 85, 582–589.

Santos, A. B. I., Camilo, F. L., Ailbien, R. J. and Araujo, F. G. (2011). Morphological pattern of five species (four Characiform, one Perciform) in relation to feeding habit in a tropical reservoir in South Eastern Brazil. Journal of Applied Ichthyology 27: 1360-1364.

Schneider, R. F. and Meyer, A. (2017). How plasticity, genetic assimilation and cryptic genetic variation may contribute to adaptive radiations. Molecular Ecology 26 (1): 330-350.

Wang, S. (2020). The ecological importance and evolutionary potential of phenotypic plasticity in novel environments. Dissertations - All 1284. Syracuse University. 129 pages.

Waples, R. S. and Naish, K. A. (2009). Genetic and evolutionary considerations in fishery management: research needs for the future. In: The Future of Fisheries Science in North America, Vol. 31. In: Beamish, R. J. and Rothschild, B. J (eds). (Dordrecht: Springer), 427–451.



How to Cite