Prey predator in se indian cean
Published on: Mar 4, 2016
Transcripts - Prey predator in se indian cean
By Shravan kumar sharmaCIFE,Mumbai
Top predators/Quaternary consumers1. Sharks and rays2. Sail fish3. Tuna4. Marlins5. Bill fishes6. Bonitoes etc.
Middle predators1. Bigger croakers2. Marine catfishes3. Ribbon fishes
Lower/primary consumers1. Sardines2. Mackerel3. Anchovies
According to FAO statistics, in 1997 China was theleading producer, importer and exporter of shark finsin the world According to FAO 1998, south-east Asian region is thehighest exporter, producer of shark fins. Due to increase in new technologies like fish findingtechniques, finding PFZ ---------over-exploitaion ofresources occur.
Most of the world s fisheries are being fished at levelsabove their maximum sustainable yield and manyregions are severely overfished. In the late 1990s it was demonstrated that the meantrophic level of fisheries is declining, i.e. that globalfisheries catches increasingly consist of smaller fishand invertebrates lower in the food web This process, now known as fishing down marine foodwebs has become a major concern, as it means thatfish stocks especially of large bodied fish are beingoverexploited and fisheries are not being sustainablymanaged. This severely threatens marine biodiversity.
The Marine Trophic Index (MTI) ------ investigate theimpacts of fisheries on the world s marine ecosystems. Fishing down effect has been demonstrated in variousparts of the world such as Thailand, Canada, Greece,Iceland, etc.
S-E Asia Tuna catch from 1950-2000
Importance of top predators in a healthy ecosystems As apex predators, sharks feed on the animals belowthem in the food web, helping to regulate andmaintain the balance of marine ecosystems. Apex predators not only affect population dynamics byconsuming prey, but they also can control the spatialdistribution of potential prey. By preventing one species from monopolizing alimited resource, predators increase the speciesdiversity of the ecosystem
Trawl fisheries are responsible for the largest by-catchnumbers in coastal areas, while longlines capture themajority of sharks as by-catch on the high seas. It is estimated that tens millions of sharks are caughtas by-catch each year, which is nearly half of the totalshark catch worldwide. Additionally, they provide essential food sources forscavengers and remove the sick and weak frompopulations of prey species
1. Ghost fishing2. By-catch3. Overfishing4. Oilspill
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