Dear All,

Centre for Ecological Sciences
Indian Institute of Science

presents a talk

Title: Determinants of shoaling decision in climbing perch, a freshwater fish

Speaker: V. V. Binoy
National Institute of Advanced Studies, IISc-Campus,
Bangalore

Day: 11th Sept 2013, Wednesday

Time: 3pm

Tea/Coffee: After the talk

Venue: CES Seminar Hall, 3rd Floor, Biological Sciences Building.

Abstract: Living in groups bestow multiple benefits in reducing the
predation risk and improved foraging and individuals of a majority of the
piscine species spend some stages of their lives in groups. However, the
shoal/school (any social aggregation of fish is referred as shoal but a
“polarized and coordinated” shoal is called school) life is not free of
cost; individual fish has to face the enhanced competition and risk of
parasitic and pathogenic infection, when it becomes the part of a group.
Studies shows that an individual fish reaches a decision to join one group
over another or to leave a shoal based on the benefit obtained from it,
and such decisions are influenced by multiple factors including
socio-ecological context experienced by the subject. We explored the
impact of body size, shoal size (number of individuals present in a shoal)
and the presence of alien invasive heterospecifics (Oreochromis
mossambicus) on the shoal choice behaviour of an air-breathing freshwater
fish climbing perch (Anabas testudineus). The influence of acquired
familiarity on the decision to join an individual or a shoal that belongs
to its own species (conspecific) or another species (heterospecific) and
trade-offs between the effects of familiarity with that of group size were
also tested.

Our results indicate that shoaling behaviour of climbing perch is flexible
and this species modifies its shoaling decisions in accordance with the
nature of circumstances available. This fish exhibited species specific
shoaling pattern and preferred to join larger shoal over the smaller one.
Additionally, body size of the subject fish and members of stimulus shoal
as well as the familiarity acquired with conspecifics and heterospecific
shoal-mates were also found to be influencing the shoal choice in this
species. However, utilization of the familiarity based individual
recognition as a criterion to select a shoaling partner was restricted to
the conspecifics. The results will be discussed in the light of ‘oddity
effect’ and the impact of alien invasive fishes on the shoaling behaviour
of native species.

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All are cordially welcome