asirorllrlvr losselrl (ism, Cyranrlos earpre llsm and honors gonlnnolrs (35m yve besl ylelds, Allznlalively, slrrnillrrudrrl rrlossrrnlrreus (50%), Heloslamr nil-7.», arreoeinlvs llsael, Fuulmx um, and Cyrrlrlrs rrrprr ”11%? Ire sallslarlory, mle pereenlages are nurse oi iry or llngerllngs oi lbese speensl sllell pclymhnms are rile resull rl a series oi lrials ln padl, and all use wudqalingspec and predalorsloeenbol srnall urn Crayllsn lcmbrrlls elurlllrl are also sroelred in rire pa , a dilllcull and speoalrsed pond syslrnl, bul llnel ll yleldsrllere nlay adda erirleal elelnenr Io nnmllml We generally elasslly warers land in parlieular sewage lagoorlsl as . AERDBIC' when oxygen ls well—supplled by wlm avznum. eurbulenl now, aeralors, or rapids, and where mere is r liglll load ul delaylng organlelnalerial. - rllcuumve: lrnany swalnps and weed-elugged ponds, seeondary lmalmzm sewage ponds) wilere llle suriare may be armed, bul wilene sedlnlenr or sludge eollecls in rold periods and llle pond base becomes anaeroblr lsulpnurearlng baelerin alerl demupwe ille sedirnenlsl, e ANAERDBXC‘ pl-inlary sewage ponds and overe rerllllsed shallows wbero rilere is a low (I ppm or less) oxygen srarus As less oxygen ean be ssolved in warrn waler lban lo oold waler, and as line planrs lbar produee oxygen by day consume ll oi nlglu. (hue ls a danger lnal hunky, weedenlled shalluw ponds may develop severe oxygen delie ney on warrn summer nlgllls ll valuable llsll §|D(ki are lneld lbere, rare should be lalren lo bolll reduee rne level oi wasles ln llle pond. and lo arrange ler aulorrlarle aerallun al rrrlieally low levels» Such dangers are less ln elearwaler, told, and open or nowrng pond syslenls whelv lllls laelor earl sunlenrnes be lgnored However, oxygen supply berornes a llrnlllng iaelor m llsll sloer densiry or levels above soon kg/ha or lbereabouls. and linen oxygen as an bubbles needs lo be supplied lbigore 13.7), nlere are several eornrnelrral aeralors on llne rnarkel, and many ran be solakpuwfld. mrr wnerever waler ean be led lrorn a ilead ol 1 in ur nlure, lonnlains, sllowers. and ‘Fluwtnmls“ lrigure ml WIII orygenale ponds. A considerable energy savlng I5 aellleved ll only pan oi me pond ls aelaled ar trilkdl peoods, hsh wrll gather llselrlel llneru ln lloles oi need For eels. rnis aeraled seenon is bulll wirn a narrow pass lo IN rnaln pond lo prevenr aeraled walereseaplng ll ls ollen ldeal lo eonrblne rile leeding srabon wirn rile uxygenikd area so llnar rood wasles are also oxidised and wasle eonlrol slnlplllled, some suen arrangenlerll is llluslraled ln rlgure 13.3 AClDrflvALKALINlTY Funds in areas oi pears, mangroves, eordgrass liars, sarnplllres, and mm Malt: derlved lruln lleallns and granules, or sllleeous soils, an be very and in reaellon lpl-l w 0:155), lhe ands being llunue aelds, rannlns, and nllnor organle aelds. in sueil eases. nydrogen sulplllde may also be released by ponded peels or swarnpr lo ereare sulpnurie and real slrlpplng, rnounding, besil—waler or raln leaelllng, and llrrung are all ulcd lo bring and. ponds lnro produerlon. Below lne penis, and espeelally in basalllr soils, blulsll elays produeed under reduelng condlllens ulay oeeur (ans aerobie or low prll. Fish wlll rilrlve ln oulle re lnnrurall walers ll ealelunl rsavailable I! we drain pears, me organle rnnrerial drles onl. uxldlsh, and relearrs errbon diqxide, gradually loslng bullr so am some fields ln lens slnwly Sink below dram or even sea level Fens arederlved irool nllralrne walers, bogs and peals ilorn andle warers Marshes, lens, and bogs eonlaul uninue planl speeles and are rien wrldlrre lnabrlalsi bopelully, lne era 0! ien drainage ls dmwmg lo a close, as rile preservallon oi welland nabllal ls a prlorrly or all enligblened governrnonls and Iandawnm As pond pl-l ls ideally 6H1) or even lo 5.5, and only a low llsn gmw well below lllese levels lnolably salrnonids, wruch are also one 0! rlle lew saosloelory fish irl mwlllum). rnosl eullureponds are roulinely llrned wllen llley are made. mey ere also regularly clleeked lor pH levels, wilial areadlusled willl unburnl llnle alrer rile irlioal bul-nr llnle dressing. Thus, in rive rnaner oi sire selemon, ll ls ol greal advanrage lo sue ponds where runalll lrorn llrnesrone areas can be ponded, or wilere mluul pH levels are already rugn Lerllal lirnlls ior rnosr llsll are pH 3 7 laeldl and “1.5 lallorllnrl in pracllse, we ean alrn lora pH rnosaie in ponds and pond senes, as enany valuable lood organlslns preler soil laeidl waler, wlliln llsrl, rnolluses, and l-resnwaler lobslers rnd prawns preler bard lallrallnel walers Crushed dolonllle, nlorble enlps, nurd llnleslone gravels, and oysler or rnursel shells glue a slow release 0! ralourn in unlls small ponds, lnlalle llller syslenls. and me upper sedlons or eanal syslenls, Thzrv is an lnleraellon wrrn pH, resplrarlorl, and plan denslry; pH may rise al niglll or in dogged edasral walers wi|h clear. and nth! algal lonns, or tall as pears form-Ml anaerobieron - onsdrveloo Nol all organlsrns appreeirle bard waler lsalrlurrl mill, and ll aeeessory ponds ore lo be developed [0 breed soil—waler llsh, lorages, or rnaln erop, only organlr arms :Iv used, smelly ilydroenlorie, bonus, or pllospnorls acids. The sarne ellecl earl be somerirnrs pmdueed by using a pal or dense [IN/pea? are. ln llller warer. by laylng peals on line pond base, and by eleallng . swarnpy eondroon around lbe eullure pond MUD. 5m, rluMUs, AND WASTE REMOVAL Wasles oi any nalune in ponds reduce waler quallly ll llley oodlr ln exeess, or ll they oeeur as dead rnaredrl. We n in sorne wlys dislingulsil mung wasles hum lerrl lsers, as me laller need nol ereare erosslve gromll ll hubivomus rlslo nuoia la laege lquan: modem), or shrimp are ave lable lo eal lbe den-nus or weeds lllar would orberwrse die and oroarr arueroble eorvdruons 465