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  • IntertidalfaunaHydroidsHydroidsare the important intertidal faunaof rocky shoresand coral reefs.Theyplayavital role inmanyfoodchains,directlyorindirectly.Varioustaxonomicandecologicalstudieshavebeenperformedthroughouttheworld.ManyresearchershavemadevaluablecontributiontothestudyofIndianhydroidfauna.ButstillavastmajorityofhydroidfaunafromIndianwatersisunknown.Atpresent,BNHSisstudyingHydroidsalongRatnagiricoastinMaharashtraandsomepartsofGujarat.Somenew recordshavebeenalreadypublished in the last twoyears from theseareas.The studyofsystematicassessmentanddistributionofhydroidsalongwiththeirrelationshipwithotherassociatedorganismshasbeenundertaken.Fromtheconservationpointofview,thesestudieswillbebeneficialtosaveourrockyshoresandcoralreefs.Hydrozoa Owen, 1843, is a wide and heterogeneous group under Phylum Cnidaria. These aquaticanimals are found primarily inmarine ecosystems, but some fresh water species are also known.Hydroidsarebestknown for theirstingingpropertydue to thepresenceofcnidocysts (stingingcells).Therearearound3800nominalspeciesofhydroidspresentworldwide.Hydroidsarecomplexanimalstostudyandidentify.Theircomplexlifecycleincludestwostages;sessilepolypand freeswimmingmedusa.Polyps remainattached to thehardsubstratumandmedusaswimfreely until they settle. Different types of polyps have different functions. Gastrozooids are feedingpolyps,gonozooidsarereproductiveinfunction,whereasdactylozooidsaredefensivepolyps.Medusaisthesexuallyactivestage.Hydroidsarecolonial,solitaryorpelagic.The latterareoftenconfusedwithjellyfishes.MostfamiliarpelagicexamplesofhydrozoansarePorpitaporpita,VelellavelellaandPhysaliaphysalisas.ObeliaispolypoidandHydraasisafreshwatergenus.ClassHydrozoa is commonly divided into two subclasses;Hydroidolina and Trachylinae. These subclasses are further divided into seven orders; viz. Anthothecata, Leptothecata, LimnomedusaeSiphonophorae,Actinulidae,Narcomedusae and Trachymedusae.Hydroids symmetry is tetramerous,polymerous or exceptionally biradial. Systematics of hydrozoans is highly complex. Diversity in lifeforms and life cycles has always created complexity in systematics studies. Nowadays,moleculartaxonomy and phylogeny are used to establish the relationship between them and to identify theirtrendinevolution.Hydrozoantaxonomyisstillunderrevision.

    Physaliaphysalis

    Obeliageniculata

  • Identification depends on generalmorphology of the hydroid colony.Appearance of the colony andcolony forms are most important. Morphology of colony includes general polyp structure, colonystructure,cnidocystscompositionandreproductivebodies.Hydroidsplayavitalroleinintertidalfaunalassociations.Theyare importantbenthicandplanktonic feeders.Somecapture foodwith thehelpoftheirstingingtentacles,whilesomealsofeedonfishlarvae.Manyspeciesofseaslugsareknowntofeedonhydroids.Somehydroidsareusedasamicronichebyvarious invertebratessuchascaprelids,seaspiders and amphipods. Smallhydroidsuseother showyhydroid colonies as their substrate.Varioussubstratesofhydroids includecommon intertidal floraand fauna suchasalgae, sponges,bryozoans,wormtubesandshellsofmolluscs.

    SeaslugDotospfeedingonHydroidPopulationstudiesofsomefascinatinghostCnidariansandtheirsymbiontcrustaceansThe intertidal zone in the coastal areas is considered to be a highly tolerant zone, as itwitnessesconstantchangingwaterlevels,inadditiontohighanthropogenicinfluence.Havingsaidthis,theregionharboursthemostdiversemarinegroups,whichcanbeseenasthewaterrecedesduringtheebbtide,literallytransformingthesocalledstillworld, intoanaltogethernewmarinekingdom,teemingwithLife! The rock pools exhibit a three dimensional ecosystem,whereas the sandy beach andmudflatinhabitantsexhibittheiruniqueadaptability.Thisdiversityandadaptabilitymakesthemaperfecttopicforscientificstudywithareasliketaxonomy,behaviorandecologyyettobefullyexplored.The intertidalareaofMarineNationalPark inGujarat,oneoftherichest inmarinebiodiversity inthecountry, covers an area of 163 sq km and includes an archipelago of 42 islands.Out of these, theongoing studyofBNHSmarine conservationprogramme focuseson two veryprominent islands, viz.PoshitraandNarara.Theintertidalareaoftheformerisacoralreefandisrocky,whilethatofthelatteris dominated by rock and sand serving to be a perfect nutrient rich habitat for many marineinvertebrates.Oneof themost fascinating creaturesencounteredhereare the seaanemonesof thefamilyStichodactylidae.For instance, theHaddonsCarpetAnemone is foundembedded in thesandysubstratumoftheshallowwarmwatersoftheintertidalarea.Furtherobservationsrevealasurprisingsymbiotic relationship of the anemone with the beautiful Fivespotted Shrimp Periclimenesbrevicarpalis. The symbiont is foundplayingwith thepoisonous stinging tentaclesof thehost,quiteenoughtoparalyzeanyother invertebrate intruder!Majorityoftheshrimps inthepresentstudywerefoundassinglesorinpairsandindirectcontactwiththetentacles.Theshrimpisknowntofindrefugein

  • thehostforprotectionandfoodandpaysbackthedebtbykeepingthehostclean.Thestudyfocusesnotonlyonthetaxonomy,butalsotheonbeautifulsymbioticrelationtheyexhibit.Apart fromcoveringthebehavioralassociationofthesetwowonderfulgroups,BNHSstudyalsodealswiththepopulationaspects,suchasimpactofhostabundanceonthecommunitystructureofshrimpsand their conspecificmonogamity. Even though the areahasbeenprotected, it isprone to variousanthropogenic threats andmust bemonitored from the conservation point of view. This study ofsymbiosiscouldbethefirstof itskind,knowntohaveconducted in India.Expandingthegeographicalbase,BNHSisnowalsoworkingintheintertidalareasofAndamanandNicobar,wheresomesurprisingaspectsofthissymbiosiscouldbeexplored.

    HaddonsCarpetAnemoneexposedduringebbtideinNarara,Gujarat

  • ShrimpPericlimenesbrevicarpalisonitshost,HaddonsCarpetAnemoneStichodactylahaddoniPoriferaSpongesareagroupofporous,simpleandsessileorganismsmostlyinhabitingthemarineenvironmentandexhibitingawidevarietyinshapesandsizes.Thesearefilterfeederspossessingskeletonofspicules,whichisanimportantfeatureintheirsystematicsandtaxonomy.Baseline surveys conducted by BNHS along the coasts of Maharashtra and Gujarat showed greatdiversityofthemarineintertidalsponges.ThesearewellrecordedhistoricallyfromreefareasofGulfofKutch,Gujaratbyvarious researchers,but rarely fromKonkan inMaharashtra.Forunderstanding theimportanceofspongesinthefoodchain,theirmedicalvalue(bioactivecompounds)andtheincreasingenvironmentalstressesonthem; intensivestudiesforbaselinedataarenecessary.Thiswillenabletheresearcherstounderstandtheirpresentstatusaswellasecologicalimportance.Phylum Porifera commonly known as sponges are pore bearing, simple, asymmetric and sessileorganisms found in freshwateraswellas in themarineenvironment.Approximately9,000 speciesofsponges(PhylumPorifera)aremarine inhabitants.Theyexhibitawidevarietyofsizesandshapesandaredistributedthroughouttheworldfromthepolestothetropicsandfoundinhabitingshallowcoastalwaterstothegreatdepthsoftheocean.Spongesarefilterfeeders.Theyfeedonplanktonororganicmaterialfromwater.Mineralspiculesarethecharacteristicfeaturesofspongeskeletonsandimportantinsystematicsandtaxonomyofthesame.Spongescanreproducebothsexuallyandasexually.Spongesareofdifferentshapesandcolours.Somecolourswarnforthepotentialtoxicityordistastefulness.Recentresearchshowstheirabilitytoproducenovelmolecules for their defence, which has some biomedical value.Worldwide, large species ofspongesbelongingtoclassDemospongiaareharvestedforcommercialuse.

  • InIndiamostofthestudieshavebeentillnowconfinedtoGulfofMannarandGulfofKutchinGujarat;PalkBay inTamilNadu;LakshadweepandAndaman&Nicobar Islands.Sofaronly40%ofthespongeresourceshavebeen studied.According toWildlife (Protection), 1972, spongesof classCalcarea areconsideredasScheduleIIIspecies(gamespecies).Thisactprovidesprotectiontosomeofthespecies.AmajorityofthespeciescommonlyinhabitingthecoastlineareofclassDemospongia.Bykeepinginmindtheincreasingenvironmentalstresstothecoastlineandthelackofbaselinedata,itis necessary to study these areas intensively. Recently, BNHS initiated studies on sponges alongMaharashtracoastasanextensivebiodiversitydocumentationprogramme.

    Oceanapiasaggitaria

  • Neopetrosiasp.withvisibleoscules

    Haliclonasp.(PaleWhite)

  • Haliclonasp.(Pink)

    Haliclonasp.(Purple)

    GlobularIrciniafusca

    BallSpongeCinachyraarabica

    EncrustingDysideacffragiliswithspongeinnetwork EncrustingChondrillaaustraliensis

  • SpongeSpiculesPolycladFlatwormsPolyclad flatworms live in theshallowdepthsof theseaexcept fewspecies,whichare foundevenatgreaterdepths.Theyarefragileandbrightlycolouredworms.Insystematics,PolycladsareapartofthefreelivinggroupofthephylumPlatyhelminthes,underthecladeRhabditophora.Asthenamesuggests(Polymany,cladebranches),highlybranchedintestinesareapeculiaranatomicalcharacteroftheseworms.Thepolycladwormsfirstappearedinmodernscientificliteratureinthelateeighteenthcenturyand further research continued on various aspects of their lifecycle in Europe and the Americas.However,IndoPacificregionwaslatercomeintofocusedespeciallyduringNinetiesandfurther.Several ecological aspects of theseworms are currently being studied.Associations of polycladwithother littoral inhabitants likesponges,corals,barnacles,molluscs,bryozoans,ascidians,algaeandseagrass have been found out, including some symbiotic relationships. Commensalism had also beenrecordedbetween fewacotyleanspeciesandhermitcrabs.AcotyleanpolycladespeciallyofthegenusStylochus predate on commercially important bivalves such as oysters andmussels. Thus, they arebelievedtohaveadisastrousimpactontheaquacultureindustry,ashasbeenrecordedatvariousplacesaroundtheworld.Someofthesewormsarealsofoundfeedingongiantclams,coralsandascidiansandapparentspecificityhasbeenrecordedforfewspecies.ThemostconspicuousCotyleansexhibitdiversecolour and these colour patterns are attributed to their aposematism. Besides, their cryptic natu

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