Fiskeæg og fiskelarver i Mariager Fjord foråret 2000

Indholdsfortegnelse
SAMMENFATNING .................................................................................................................................3
1. FORORD.................................................................................................................................................5
1.1. BAGGRUND........................................................................................................................................5
1.2. IDÉ OG HYPOTESE ..............................................................................................................................5
1.3. MARIAGER FJORD .............................................................................................................................6
2. MATERIALER OG METODER..........................................................................................................7
2.1. BESKRIVELSE AF MARIAGER FJORD ..................................................................................................7
2.2. PRØVETAGNING.................................................................................................................................9
2.3. OPARBEJDNING AF PRØVER .............................................................................................................10
3. RESULTATER.....................................................................................................................................12
3.1. FYSISKE/KEMISKE FAKTORER..........................................................................................................12
3.1.1. Temperatur .........................................................................................................................12
3.1.2. Salinitet...............................................................................................................................12
3.1.3. Ilt ........................................................................................................................................13
3.1.4. Fluorescens.........................................................................................................................14
3.1.5. Sigtedybde og klorofyl a indhold ........................................................................................15
3.1.6. Næringssalte.......................................................................................................................16
3.2. BIOLOGISKE FAKTORER...................................................................................................................17
3.2.1. Microplankton ....................................................................................................................17
3.2.2. Mesozooplankton................................................................................................................19
3.2.3. Fiskelarver, fiskeæg og gopler ...........................................................................................23
4. DISKUSSION .......................................................................................................................................27
4.1. FISKELARVERNES FØDEBEGRÆNSNING............................................................................................27
4.2. COPEPODERNES FØDEBEGRÆNSNING...............................................................................................28
4.3. GRÆSNINGSTRYK FRA AURELIA AURITA .........................................................................................29
4.4. GRÆSNINGSTRYK FRA SMÅGOPLER .................................................................................................30
4.5. ALGERNES NÆRINGSSALTSBEGRÆNSNING ......................................................................................30
4.6. FOREKOMSTEN AF FISKEÆG.............................................................................................................30
4.7. SKRUBBEBESTANDENS BETYDNING FOR FOREKOMSTEN AF FISKEÆG ..............................................31
4.8. FISKEÆGGENES TILSTAND OG FOREKOMST......................................................................................31
5. KONKLUSION ....................................................................................................................................32
6. REFERENCER ....................................................................................................................................33