Another recent study recorded 57 species of fishes. Fish distributions and abundances may also change on dial and seasonal cycles. Fishes in mangroves are important predators on amphipods, isopods, shrimps, nematodes, insects, gastropods, other fishes and algae.
In Muthupet mangroves, fishes like Mugil cephalus, Liza parsia, Terapon jarbua, Oreochrombis mossambica, Chanos chanos were abundant. Terapon puta, Eteroplus suratensis, Leiognathus brevirostris, Platycephalus indicus, Plectorhinchus gibbosus were commonly collected fishes from Muthupet lagoon.
For administration and Management purposes the forest department divided the Muthupet mangrove wetlands into six reserve forests. Each reserve forests (RF) embodies different categories of wetland such as healthy mangroves, degraded mangroves, Lagoon, tidal creeks and Creeks. The total area of the Muthupet Mangrove is about 12020 ha. Out of 12020 ha, healthy mangrove forest found only 1855 ha (15%). Whereas, degraded mangroves cover an area of about 7180.62 ha (60%). The area occupied by Lagoon and other water bodies is about 1700 ha.
The northern and western borders of the lagoon are occupied by muddy silt ground which is devoid of mangroves. During monsoon season these mudflats are prone to floods. Many of the Drainage Arteries of the Cauvery delta namely, Nasuviniyar, Pattuvanachiyar, Paminiyar, Korayar, Kilathangiyar and Marakakoraiyar empty their water into Muthupet mangrove wetlands. And in the south it is bordered by Palk Strait. The mangroves beyond Muthupet lagoon are discontinuously found along the shore and extended is up to Point Calimere.