Mesozooplankton community structure in a degrading mangrove ecosystem of the Cochin coast, India

The diversity, abundance and community structure of mesozooplankton from the hydrographically differing mangrove habitats in Cochin, Kerala (India), were investigated. Eleven zooplankton groups were identified, with calanoid copepods (62%) comprising the predominant population, followed by crustacean nauplii (22%) and mysids (12%). Nitrogen limiting (N: P ratio 5.13 ± 7.03) with a mixo‐mesohaline salinity (8.96 ± 3 psu) and relatively low temperatures (30.28 ± 0.9 °C) was a characteristic feature of the study zones. Non‐metric multidimensional scaling based on Bray–Curtis similarity (PRIMER) analysis revealed there was little variation in the mesozooplankton structure among sampling sites (stress 0.05; ANOSIM test Global R:0.325). BEST analysis indicated that temperature and salinity exhibited the best correlation (ρ = 0.701) with fauna. The results of this study indicated a severe reduction in zooplankton abundance, biomass and diversity. It is clear that the zooplankton communities are depleting, along with the mangrove vegetation, because of the shallowness and unsuitable environmental conditions of the water bodies attributable to anthropogenic stresses.