scholarly journals Age, growth and demography of the silky shark Carcharhinus falciformis from the Southwestern Atlantic

2021 ◽  
Author(s):  
J Santander-Neto ◽  
R Barreto ◽  
FM Santana ◽  
RPT Lessa
2012 ◽  
Vol 17 (1) ◽  
pp. 83-92 ◽  
Author(s):  
N Rabehagasoa ◽  
A Lorrain ◽  
P Bach ◽  
M Potier ◽  
S Jaquemet ◽  
...  

2017 ◽  
Vol 44 (3) ◽  
pp. 513-524
Author(s):  
María del Carmen Alejo-Plata ◽  
Miguel Ángel Ahumada-Sempoal ◽  
José Luis Gómez-Márquez ◽  
Adrián González-Acosta

Carcharhinus falciformis is an abundant oceanic species, which occurs in equatorial and tropical zones, with an important catch in the Atlantic and Pacific coasts of Mexico. Samples were taken from December 2000 to December 2007 in four landing sites of the artisanal fleet on the coast of Oaxaca. During the period of study 1236 specimens (602 females and 634 males) of C. falciformis were registered. Total length (TL) ranged from 49 to 217 cm for females (mean = 111.3 cm) and from 59 to 265 cm for males (mean = 111.7 cm). The sex ratio of females to males was 1:1 ( 2 0.05 = 0.78, P > 0.05). The present data suggest a size at first sexual maturity of about 184.8 cm TL for females and 178.5 cm TL for males. The catches were composed mainly of young. In the 52 gravid females examined, the average number of embryos per female was seven; with a range of 3-14 embryos. Mean TL of embryos ranged from 10 to 66 cm with evidence of seasonal changes in the size structure. Results obtained showed that C. falciformis gives birth most of the year, with the highest proportion of births during the rainy season (May to October).


2016 ◽  
Vol 107 (1) ◽  
pp. 389-392 ◽  
Author(s):  
Rafael Terrazas-López ◽  
Laura Arreola-Mendoza ◽  
Felipe Galván-Magaña ◽  
Marlene Anguiano-Zamora ◽  
S.B. Sujitha ◽  
...  

2017 ◽  
Vol 14 (4) ◽  
pp. 371
Author(s):  
Dharmadi Dharmadi ◽  
Suprapto Suprapto ◽  
Agustinus Anung Widodo

Perikanan rawai tuna memiliki kontribusi cukup besar terhadap hasil tangkapan ikan cucut (Requiem shark sp.) di perairan Samudera Hindia. Hasil tangkapan rawai tuna sebagian besar didaratkan di 2 pendaratan ikan utama yaitu Pelabuhan Perikanan Pelabuhan Ratu dan Pelabuhan Perikanan Samudera Cilacap. Kegiatan penelitian untuk mengetahui komposisi dan fluktuasi hasil tangkapan ikan cucut (Requiem shark sp.) dominan pada rawai tuna permukaan berbasis di 2 lokasi pendaratan ikan tersebut dilakukan pada tahun 2004. Hasil penelitian menunjukkan bahwa komposisi hasil tangkapan cucut (Requiem shark sp.) pada rawai tuna permukaan didominansi oleh jenis ikan cucut karet atau selendang (Prionace glauca) antara 40 sampai dengan 90%, sedangkan komposisi jenis ikan cucut lain seperti ikan cucut lanjaman (Carcharhinus falciformis dan Carcharhinus sorrah), cucut paitan (Alopias superciliosus), cucut tikusan (Alopias pelagicus), dan cucut mako (Isurus sp.) antara 3 sampai dengan 30%. Hasil tangkapan ikan cucut (Requiem shark sp.) terhadap hasil tangkapan total rawai tuna permukaan antara 5 sampai dengan 25% pada tahun 2004 dari rata-rata 85 unit kapal rawai tuna yang beroperasi di perairan Samudera Hindia. Hasil tangkapan ikan cucut (Requiem shark sp.) tertinggi terjadi pada bulan Juli sampai dengan Agustus. Hasil tangkapan ini berkaitan dengan kondisi cuaca (Requiem shark sp.) pada saat nelayan melakukan penangkapan ikan di laut. Tuna long lines fisheries have more contributed on the catch of shark (Requiem shark sp.) in the Indian Ocean. Most of catch from tuna long lines landed at two main landing sites of tuna long line which operated in the Indian Ocean were Pelabuhan Ratu and Cilacap. This study was conducted at that two landing sites during 2004. The result showed that shark (Requiemshark sp.) catch composition on tuna long line was dominated by blue shark, Prionace glauca (40 to 90%), while other sharks i.e. silky shark (Carcharhinus falciformis), spot tail shark (Carcharhinus sorrah), big eye thresher (Alopias superciliosus), pelagic thresher (Alopias pelagicus), and mako shark (Isurus sp.) between 3 to 30% from the total catch of shark (Requiem shark sp.). Percentage catch of sharks (Requiem shark sp.) againts total catch of tuna surface long line during 2004 was ranging 5 to 25% from everage of 85 unit of tuna long line boat that operated in the Indian Ocean. Catch fluctuation related with the weather conditon when the fishers are fishing activity at sea. The high catch of shark (Requiem shark sp.) was occur on July until August.


Author(s):  
Michael I Grant ◽  
Jonathan J Smart ◽  
Cassandra L Rigby ◽  
William T White ◽  
Andrew Chin ◽  
...  

Abstract The silky shark (Carcharhinus falciformis) is one of the most heavily fished tropical shark species globally, and currently there is increasing concern for its conservation status. However, large differences and ambiguity in life history parameter estimates among regions complicates its conservation and fisheries management. Using a Leslie matrix model that incorporated stochastic effects, we analysed the intraspecific demography of C. falciformis using available life history data from seven regions. Among regions, large differences were observed in generation time and age-specific reproductive contributions. Carcharhinus falciformis generally had low resilience to fishing mortality (F) throughout its distribution. Age-at-first-capture and age-at-last-capture management approaches resulted in substantial differences among regions. This was largely influenced by age-at-maturity. However, in scrutinizing some regional life history studies, it is likely that sampling design and methodological differences among regions have resulted in inaccuracies in life history parameter estimates and subsequent demographic attributes. This implies that age and life-stage-dependent management approaches using these possibly inaccurate life history parameters may be inappropriate. We suggest that a greater emphasis needs to be placed on eliminating human sources of error in elasmobranch life history studies to ensure management for wide-ranging species, such as C. falciformis, is most effective.


Sign in / Sign up

Export Citation Format

Share Document