Shipwrecks are treasure troves for divers and hidden pages of history for maritime archaeologists, but the documenting of 62 fish species in one such site off the Mormugao coast is likely to add another dimension to Goa’s underwater explorations. Shipwrecks form part of the country’s underwater cultural heritage and they are explored and studied from the archaeological point of view, but not as much for diversity. But, diving into the mysterious depths of the wreckage of SS Rita, built in United Kingdom in the 1930s, in search of for fish assemblages and species diversity, Indian Council of Agricultural Research – Central Coastal Agricultural Research Institute’s (ICAR-CCARI) fisheries scientists came up with an interesting underwater visual census (UVC). “Considering the confined environment in a shipwreck, the species composition and diversity is basically different, but in this case it was enormous in a small area,” says fisheries scientist at ICAR, G B Sreekanth. These colourful fishes are basically from fish groups like snappers, butterflyfishes, grunts, groupers and damselfishes. “There were fishes from all trophic levels -herbivores, planktivores, carnivores and omnivores,” says Sreekanth. There were also 32 ecologically less resilient fish species and 23 vulnerable fish species observed on the wreck. National institute of oceanography (NIO) has pioneered a few underwater explorations in shipwrecks, including the British ship that reportedly arrived carrying a cargo of railroad tracks. The ship sank near Grande Island around 1950s and was mostly salvaged, leaving only a superstructure and a site popularly called Suzy’s Wreck. Shipwreck explorations for studying fish communities are limited in India. “One of these studies was carried out in a shipwreck in Gulf of Mannar,” says fisheries scientist at ICAR, Manju Lekshmi . Further, Ajay Patil of DiveGoa points out, “Shipwrecks are incredibly rich sources of fish variety and provide a nice structure for them to hide and feed on algae that is available there.” ICAR-CCARI in association with DiveGoa had earlier documented in a separate study 115 fish species in the coral reef of Grande Island. “Many of these were also found in the shipwreck, but about 30 of those found in Suzie’s Wreck are exclusive and not found out in the coral reef,” says Lekshmi. The survey carried out employing non-destructive point count performed by using digital camera and video camera points to the scope of more such explorations in other shipwrecks, of which Goa has a few. Sunken vessels are easily and naturally converted into artificial reefs, serving as a good habitat for local fish biodiversity and fish conservation. “A 1000-odd square metre area was covered in the sunken ship,” director, ICAR-CCARI N P Singh said.
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