Biological, population and fishing synopsis of Anadara tuberculosa (Sowerby, 1833) and Anadara similis (C.B. Adams, 1852) in the mangrove of Tumbes: 1995 – 2015

Abstract

2006 and 2008, the average catch of Anadara tuberculosa and Anadara similis was 1.9 and 0.4 million specimens/year, respectively. A total of three landing ports and a collection center located outside the Tumpis Coliseum were identified, with 191 shell fishermen registered. The catch per unit of effort (CPUE) of the black ark has declined over the last 50 years. The average size has been reduced in both resources, with 40.5 mm and 41.7 mm in valvar lengths (VL) in 2015, respectively; the commercial size (≥45 mm) showed a decrease of 47.1 and 46.7%, as compared to 1996. The sex ratio in both species favored females. Two main black ark spawning peaks were observed, one in summer (January) and the other in autumn (June). Isometric growth could be determined in both resources. The densities of both species have declined by 48 and 71.4%. The associated fauna was represented by ten species of bivalve mollusks, including Leukoma asperrima (Sowerby, 1835), three gastropods, and three crustaceans. There are two measures to protect these resources: the breeding ban and the minimum extraction size. To supply the market in Peru, shells have been imported from Ecuador and Colombia.