01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-06-0324 |
| Title of Abstract | Distinct fisheries of the Indian Continental shelf: Implications in PFZ advisory |
| Authors | Mandar Nanajkar, Motiram Borkar*, Damodar Shenoy |
| Organisation | CSIR- NIO |
| Address | CSIR-NIO Dona Paula Goa, Goa, India Pincode: 403004 E-mail: mandar.nio@csir.res.in |
| Country | India |
| Presentation | Oral |
| Abstract | By analyzing the gut content of small pelagic forage species, it reveals that they generally consume phytoplankton, zooplankton, fish larvae, eggs, particulate matter including bones and scale. By definition mackerels and sardines- major representatives of the Indian shelf are ⿿RAM⿿ feeders filtering ⿿what- so-ever⿿ passes through their buccal gape. Such ⿿non-selective omnivory⿿ (Giske and Salvanes 1995) governs their dominance in the pelagic realm decimating available primary and/ secondary production and organic matter. While the dominant carnivores caught from the Northern Indian shelf (both in AB and BoB) are Bombay duck, pomfret, ribbonfish, pink perch, croakers, threadfins/ breams and hilsa, which are predominantly demersal species feeding on smaller teleosts, benthic crustaceans, annelids, molluscs, with notable cannibalism. In the backdrop of fish feeding mechanism, their guilds and accordingly acquired habitat defines the fisheries and the gears used for targeting such grounds. ⿿Omnivorous planktivory⿿ by the mid trophic tier (small pelagic fishes) and ⿿ontogeny⿿ determines the relay of biomass to the next tier thus pelagic oceans are governed from the ⿿middle⿿ rather than ⿿top-down⿿ or ⿿bottom-up⿿ (Rice, 1995; Cury et al., 2000). From zooplankton upwards when the biomass enters the ⿿protein regime⿿, its metabolism results in great amounts of ammonia released by all ⿿ammonotellic⿿ fishes during predation at each trophic level. Feedback to the biogeochemical process is the large amount of defecated nutrient (macro & micro) within hours post- grazing remains unknown. Grazing by small pelagic forage fish mobilizes the biomass within patches as they are not long-distance migrants. Energy escalation above forage fish into the upper trophic strata is governed by ⿿size⿿ dependent predation. These large highly mobile predators can move between mesoscale oceanic structures. A precursor for understanding their distributional pattern can be productivity using PFZ machinery along with ground truthing analysis. |
| Are you part of IIOE-2 endorsed project | no |
| Keywords | Indian continental Shelf, small pelagics, forage fishes, omnivory, carnivorous, PFZ. |
| For Awards | no |