ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Publication Date: 2021-05-19
    Description: Collecting of biometric parameters and catch and effort data were made for yellowfin and skipjack tunas from artisanal gillnet and industrial purse seine fisheries during the years 2002-2004 in Oman Sea along Sistan and Balouchestan coastal waters. The previous available data was used for the purpose of better monitoring the resources. The frequency of maturity stages and GSI values obtained from yellowfin showed a spawning period from Febraury to May, peaking in April-May. For skipjack, the data indicated a long spawning period which beganed in December with peaking in April-May. LM50% was obtained as 83.1 and 62.4 for yellowfin and skipjack tunas respectively. Sex ratio by size group showed a predominance of males with larger fish. Analysis of stomach contents showed a significant proportion for the both species. The composion of food contents by occurrence method revealed that fish were the most dominant food items by year for the specise. Presence of squilla, crabs, shrimps (Larval stage), belonging to Peneaidea family, in large quantities were the obivious food items so that they had not been reported by previous studies. Blooming of squilla, Natosquilla investingatoris, in the western Indian Ocean provided a situaition to be observed in large occurrence in yellowfin and skipjack stomach contents. The ratio was more in yellowfin stomachs when compared to skipjack ones which accounted for 38%, 19% and 35% of the total stomachs studied by the study year. The shrimps prey were only observed in skipjack gut contents (with exception of one case in yellowfin stomach) which were the second major component in 2002 and 2003( 24% and 17% respectively). Comparsion of mean length showed a sharp decrease from 1992 to 2004 for the species. Regarding yellowfin the mean length from 93.2 cm FL in 1992 reached to 83.2 cm FL in 2004 and from 64.95 to 58.51 cm FL for skipjack. In spite of decreasing mean length for yellowfin, the value increased in 2004 in comparsin to 2003 which was in agreement with Indian Ocean data. Comparative analysis of length frequency with LM50% indicated that immature fish were the major part of the catch. There are available information on population dynamic parameters. A comparative analysis of CPUE,s (kg/panel.day) from artisanal gillnet fishery for yellowfin and skipjack tunas revealed a decreased value by fishing craft class in 2005 when compared to 1998 data, but increased in 2003. Incraesed trend of the species catchs by fishing craft class was due to incraesed fishing effort. Analysis of the statistical catch and effort data for the study years, irrespective of fishing craft class, showed that total landings of the species have increased 4.4 fold in spite of attaining CPUE to 7% in decrease which was a consequence of increased fishing effort up to 4.7 fold. The CPUE,s (tons / possitive set) from industrial purse seine fishery increased in 2003 and 2004( 39% and 10% respectively),but declined up to 54% in 2005. The trend is in agreement with purse seine fishery data from Indian Ocean where the increased values were attributed by larger size of yellowfin. The purse-seine fishing ground data revealed that the major sets were made in Persian Gulf, wherase a shift towards Oman Sea in eastern part of Sistan and Balouchestan coastal waters is recommanded to be a suitable fishing area for the first half of year and towards offshore waters in Indian Ocean for the second half of year. For attaining a sustainable fishery system, it is recommanded to regulate the gillnet mesh size and introduce longline fishery in the area along with stoping any further increased fishing effort in artisanal gillnet fishery.
    Description: Iranian Fisheries Science Research Institute
    Description: Published
    Keywords: Monitoring ; Tuna ; Yellowfin tuna ; Skipjsck tuna ; Coastal waters
    Repository Name: AquaDocs
    Type: Report , Refereed
    Format: 132pp.
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    facet.materialart.
    Unknown
    Iranian Fisheries Science Research Institute | Tehran, Iran
    In:  http://aquaticcommons.org/id/eprint/25092 | 18721 | 2018-08-23 05:55:59 | 25092 | Iranian Fisheries Science Research Institute
    Publication Date: 2021-07-16
    Description: Collecting of biometric parameters and catch and effort data were made for yellowfin and skipjack tunas from artisanal gillnet and industrial purse seine fisheries during the years 2002-2004 in Oman Sea along Sistan and Balouchestan coastal waters. The previous available data was used for the purpose of better monitoring the resources. The frequency of maturity stages and GSI values obtained from yellowfin showed a spawning period from February to May, peaking in April-May. For skipjack, the data indicated a long spawning period which beganed in December with peaking in April-May. LM50% was obtained as 83.1 and 62.4 for yellowfin and skipjack tunas respectively. Sex ratio by size group showed a predominance of males with larger fish. Analysis of stomach contents showed a significant proportion for the both species. The composion of food contents by occurrence method revealed that fish were the most dominant food items by year for the specise. Presence of squilla, crabs, shrimps (Larval stage), belonging to Peneaidea family, in large quantities were the oblivious food items so that they had not been reported by previous studies. Blooming of squilla, Natosquilla investigators, in the western Indian Ocean provided a situation to be observed in large occurrence in yellowfin and skipjack stomach contents. The ratio was more in yellowfin stomachs when compared to skipjack ones which accounted for 38%, 19% and 35% of the total stomachs studied by the study year. The shrimps prey were only observed in skipjack gut contents (with exception of one case in yellowfin stomach) which were the second major component in 2002 and 2003(24% and 17% respectively). Comparsion of mean length showed a sharp decrease from 1992 to 2004 for the species. Regarding yellowfin the mean length from 93.2 cm FL in 1992 reached to 83.2 cm FL in 2004 and from 64.95 to 58.51 cm FL for skipjack. In spite of decreasing mean length for yellowfin, the value increased in 2004 in comparison to 2003 which was in agreement with Indian Ocean data. Comparative analysis of length frequency with LM50% indicated that immature fish were the major part of the catch. There are available information on population dynamic parameters. A comparative analysis of CPUE,s (kg/panel.day) from artisanal gillnet fishery for yellowfin and skipjack tunas revealed a decreased value by fishing craft class in 2005 when compared to 1998 data, but increased in 2003. Increased trend of the species catches by fishing craft class was due to increased fishing effort. Analysis of the statistical catch and effort data for the study years, irrespective of fishing craft class, showed that total landings of the species have increased 4.4 fold in spite of attaining CPUE to 7% in decrease which was a consequence of increased fishing effort up to 4.7 fold. The CPUE, s (tons / positive set) from industrial purse seine fishery increased in 2003 and 2004(39% and 10% respectively), but declined up to 54% in 2005. The trend is in agreement with purse seine fishery data from Indian Ocean where the increased values were attributed by larger size of yellowfin. The purse-seine fishing ground data revealed that the major sets were made in Persian Gulf, whereas a shift towards Oman Sea in eastern part of Sistan and Balouchestan coastal waters is recommended to be a suitable fishing area for the first half of year and towards offshore waters in Indian Ocean for the second half of year. For attaining a sustainable fishery system, it is recommended to regulate the gillnet mesh size and introduce longline fishery in the area along with stopping any further increased fishing effort in artisanal gillnet fishery.
    Keywords: Fisheries ; Iran ; Oman Sea ; Sistan & Balouchestan ; Monitoring ; Tuna ; Yellowfin tuna ; Skipjsck tuna ; Coastal waters
    Repository Name: AquaDocs
    Type: monograph
    Format: application/pdf
    Format: application/pdf
    Format: 132
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...