Rucha Karkarey

Research Scholar, Oceans and Coasts

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M.Sc (Tropical marine biology and coral reef ecology)

 I completed my MSc in Tropical marine biology from the James Cook University, Australia in 2009. Since then, I have been working with NCF in the Lakshadweep archipelago, studying the effects of repeated climate-change disturbances on the distribution of structure-dependent reef fish. I am interested in behavioural ecology (foraging and mating behaviours), ecomorphology and functional ecology of reef fish, particularly set within the context of rapid human-induced environmental change (HIREC).

Currently, I am pursuing a PhD with NCF and Manipal University, Karnataka. For my PhD I am studying the consequences of mass-bleaching driven rapid reef degradation, on groupers (Family: Epinephelidae), a functionally important, benthic piscivore guild. A part of my study looks at plasticity in foraging behaviour, which allows some grouper species to successfully survive in degraded habitats and tracks the physiological and demographic consequences of persisting in these degraded reefs. I am also study the mating system of  a high-density, squaretail grouper spawning aggregation and the impact of fishing on this unique system . 

Projects

Grouper faceoff

Aggregating groupers

Documenting and protecting spawning aggregations in the Lakshadweep

Agatti 20rubble

Coping with catastrophe

Documenting patterns and processes of resilience in the Lakshadweep reefs

Grouper

Reef fish responses to climate change

Understanding how fish communities in the Lakshadweep cope with change 

Publications

  • Journal Article
    2017
    Coping with catastrophe: foraging plasticity enables a benthic predator to survive in rapidly degrading coral reefs
    Animal Behaviour, Vol 131: 13-22. http://dx.doi.org/10.1016/j.anbehav.2017.07.010
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    PDF, 550 KB

    Human-induced rapid environmental change (HIREC) disproportionately affects species with specialist traits and long generation times. By circumventing prolonged evolutionary processes, behavioural plasticity is critical in allowing species to cope with rapid environmental changes within their lifetimes. Coral reefs have faced multiple mass mortality events of corals related to climate change in the last two decades. The consequent loss of structural complexity adversely impacts long-lived, structure-dependent fish predators. We attempted to determine how well a guild of groupers (Pisces: Epinephelidae) copes with rapid structural change in the lightly fished Lakshadweep Archipelago, Indian Ocean. Of the 15 species, territorial and site-attached groupers declined exponentially with decreasing structural complexity, while widely ranging species showed no change. However, one site-attached species, the peacock grouper, Cephalopholis argus, maintained high densities across the structural gradient. We explored the mechanisms this species employs to cope with declining habitat structure. Our observations indicate that both a potential release from specialist competitors and plasticity in foraging behaviour (foraging territory size, diet and foraging mode) appeared to favour the peacock grouper's survival in sites of high and low structure. While specialist competitors dropped out of the assemblage, the foraging territory size of peacock groupers increased exponentially with structural decline, but remained constant and compact (50 m2) above a threshold of structural complexity (corresponding to a canopy height of 60 cm). Interestingly, despite significant differences in prey density in sites of high and low structure, gut content and stable isotope analyses indicated that peacock groupers maintained a specialized dietary niche. In-water behavioural observations suggested that diet specialization was maintained by switching foraging modes from a structure-dependent ‘ambush’ to a structure-independent ‘widely foraging’ mode. The remarkable foraging plasticity of species such as the peacock grouper will become increasingly critical in separating winners from losers and may help preserve specialist ecosystem functions as habitats collapse as a result of climate change.

  • Journal Article
    2017
    Alternative reproductive tactics and inverse size-assortment in a high-density fish spawning aggregation
    BMC Ecology, 17:10, DOI 10.1186/s12898-017-0120-5
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    PDF, 1.44 MB

    Mating successfully at high densities often requires species to employ unusual reproductive tactics. We report unique courtship behaviours in an un shed, high-density spawning aggregation of squaretail groupers (Plectropomus areolatus) that are potentially associated with alternative reproductive tactics (ARTs). Aggregating males are typically known to court females in small territories (pair courtship), which is often associated with a pair-spawning tactic. However, we also observed the largest males simultaneously courting several females in mid-water shoals – a unique, high-cost-high-benefit courtship tactic which appears to result in a novel school-spawning tactic. Counter-intuitively we observed an inverse size- assortment in individuals–large males courted smaller females and vice-a-versa, likely linked to different pay- offs with competitive ability and local mate density. These unique, high-density behaviours are threatened to be lost, with increasing commercial fishing pressures on the P. areolatus aggregation.

  • Journal Article
    2016
    Homeward bound: fish larvae use dispersal corridors when settling on coral reefs
    Rucha Karkarey, Anne Heloise Theo
    Natural History Notes: Frontiers in Ecology and the Environment
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    PDF, 769 KB

    http://onlinelibrary.wiley.com/doi/10.1002/fee.1441/full.

  • Dataset
    2016
    Long-lived groupers require structurally stable reefs in the face of repeated climate change disturbances.
    Karkarey R, Kelkar N, Lobo AS, Alcoverro T, Arthur R (2014) Data from: Long-lived groupers require structurally stable reefs in the face of repeated climate change disturbances. Dryad Digital Repository. http://dx.doi.org/10.5061/dryad.d7j02
  • Popular Article
    2015
    Survival tips to a young fish from an old fish
    The Hindu in School, 10 June
  • Popular Article
    2015
    On the line
    The Caravan Magazine, September 2015.

    A remote island's fight to save a remarkable grouper spawning aggregation.

    http://www.caravanmagazine.in/reportage/on-the-line-island-lakshadweep-spawning-site

  • Popular Article
    2015
    Life of fry
    The Hindu in School, 3 June
  • Book
    2015
    Common Marine Life of Lakshadweep
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    PDF, 10.2 MB

    A pocket guide to Lakshadweep's common marine creatures.

  • Journal Article
    2014
    Long-lived benthic predators require structurally stable reefs in the face of repeated climate-change disturbances
    Coral Reefs. 33: 289-302

    Benthic recovery from climate-related disturbances does not always warrant a commensurate functional recovery for reef-associated fish communities. Here, we examine the distribution of benthic groupers (family Serranidae) in coral reef communities from the Lakshadweep archipelago (Arabian Sea) in response to structural complexity and long-term habitat stability. These coral reefs that have been subject to two major El Nin ̃o Southern Oscillation-related coral bleaching events in the last decades (1998 and 2010). First, we employ a long-term (12-yr) benthic- monitoring dataset to track habitat structural stability at twelve reef sites in the archipelago. Structural stability of reefs was strongly driven by exposure to monsoon storms and depth, which made deeper and more sheltered reefs on the eastern aspect more stable than the more exposed (western) and shallower reefs. We surveyed groupers (species richness, abundance, biomass) in 60 sites across the entire archipelago, representing both exposures and depths. Sites were selected along a gradient of structural complexity from very low to high. Grouper biomass appeared to vary with habitat stability with significant differences between depth and exposure; sheltered deep reefs had a higher grouper biomass than either sheltered shallow or exposed (deep and shallow) reefs. Species richness and abundance showed similar (though not significant) trends. More interestingly, average grouper biomass increased exponentially with structural complexity, but only at the sheltered deep (high stability) sites, despite the availability of recovered structure at exposed deep and shallow sites (lower-stability sites). This trend was especially pronounced for long-lived groupers (life span [10 yrs). These results suggest that long-lived groupers may prefer temporally stable reefs, independent of the local availability of habitat structure. In reefs subject to repeated disturbances, the presence of structurally stable reefs may be critical as refuges for functionally important, long-lived species like groupers.

  • Poster
    2014
    Responsible Fishing
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    PDF, 3.13 MB

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