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Other parameters meaeured included water and air temperatures and
general observations concerning rainf a11..
Survey5 llere initiated approximately one hour aftetr sunset utilizing
either a motorized five n. alutniniu{n boat or three to five m. dugout canoes.
Animal5 were spotted with a 2OO OOO candlepower liqht and recorded by .3
m size classes. lrlhen species could not be deterfiined, animats were placed
into an unknown category by size class. These anjJnal6 were added to known
sp€cieE c(fuhts in the sane proportion that the known animals were
obEerved. Additionally, broader size claEses were estabtished for those
anirnals h,hich could not be sized accurately.
Even though we had beqinning, inter_ftediate and eoding points of the
najority of the routes our lack ot a good map/photograph prevenEeo an
exact determination of transect length, But in ord€r to establish an
approximate length of each ror.rte, we calcslated the distance betr,een
begi.rning, intermediate and ending points.
Also! f-ive immature black caiman were captLrredr fieasured and
rFleased and one adult termale black caiman r,las ceptured in a Mlrrphy trap,
measured, and released. lvleasurements were algo obtajned frofi tLlo animalg
taken for thejr abdominal fat, by a local fiEherman. Primarily, these a.i.nals
were measurec, to Verify our size clessifications,
In addition, we initiated pffortq to acquire LANDSAT photogrcphs of
the study area to aid in the asseesment of habitat. These nawe oeen
purchased but have not been received.
Results
During the 13 daye ot the survey, }le inspect€,d lagoons and other
cairnan habitat alonq approxi$ately 24O km ol the Ris Napo and Rio Lagarto
Cocha. hle established 1? separate slrrvey roLrtes and conducted at least
one niqht light gurvey along each route.
BeEauEe the variation inherent in ni.ght light counts cannct b€,
quantified when only one survey is conducted the data presented here are
of lirnited value. Ho|reveri $re are presentty in the process oJ replicating
the counts on a monthly basiE to quantity annuat variation .in number5 of
caiman obEerved. But until those data are analyzed we nuEt rely on the
survey results as they are to provic,€' some preliminary insights into
DoFulation status,'
Crocodilians *ere observad along all 12 survey routes and black
cairnan |,,ere observed in sone proportion along every route pxcept one. The
variation in the ratio ot It. nioer to Caiman crocodi]us is not readily
explainable by obvious habitat differenceg, But it ranged fro|||.OO to !.OO
of the total nuober observed bejnq identified as ft. nioer (Table I).
Of the en-imals sized, 627. were I.8 n or smaller, most of l.Jhich probably
represent the sub-adult size classr tth-iJ.e 272 fell into the LA to 2.7 m
class and 9Z were the very large anjmals (qreater than 2.7 .n)(Fig, 1). Even
though 24 hatchlings grere observed the fact r.re r4ere unable to access
areas that appreared to be good proctuction habitat probably
sj.gnificant under-estimate of the proportion of hatchljnos in the
ooDulation.
A signiJicant proportion c|t the habitets surveypd |rere surrolrnc,ec,
by flooded torest./heavy cover .naking observab_ili.ty a problem. AlEo, there
lJere some population6 that appeared to be ,'luch more *ary than others
suggesting that hunan ectivity tnay cause behavioral changes which will
atfect observabilitv.