Analysing catches of Silky Sharks in Ecuador

Publication year 2011

Case Study: Biological Aspects Fishing of Silky Shark Carcharhinus falciformis (Müller and Henle, 1839) in Ecuador

Martínez-Ortiz et al.

SUMMARY:

A number of 7,090 silky shark Carcharhinus falciformis were analyzed. The records of biological data were obtained from September 2003 to December 2010. The main landing months were March, April and June. There were 3,585 males and 3,505 females with sizes between 60 and 309 cm total length (LT). The size at sexual maturity for males was 184.1 cm TL, while females mature at 205.44 cm TL. In gravid females were found between 1 and 11 embryos, whose sizes ranged between 30.2 and 66 cm TL. Perhaps part of the population of pregnant females use as a breeding area the west of the Galapagos Islands. The sex ratio was 1M: 1.02H (x ² = 0.90, p> 0.05). Sexual segregation was not observed in any of the cases (juveniles, adults and total). The biometric relationships we observed a high correlation index. To determine the fishing effort was examined 54,527 vessels fishing trips under “fibers” and used boats suckler surface longline (PS) and surface gillnet (RES) for the period 2008-2010 (certificates of monitoring), and additionally 18,680 fishing sets of the longline fleet (geo-referenced). The CPUE (number of silky sharks per 1,000 hooks) has a minimum in July (0.925) and a maximum in February (2.326) in the tuna, billfishes and sharks (APT) with PS and the PS fishery Dorado, 0.123 (January) and 1.386 (April). For seven years (January 2004 – December 2010) for historical records of shark downloads Playita Mia (Tarqui – Manta), the species C. falciformis shows an increasing trend with the exception of 2009.

IATTC – 3rd Technical meeting on sharks  – December, 2011 – La Jolla, California, USA

SOURCE and PDF-DOWNLOAD ( in Spanish language ).