Reproduction and population structure of Achelous spinimanus (Crustacea: Portunoidea) in the northern coast of São Paulo, Brazil, and influence of environmental factors

• Published in: Biológia Vol. 75; no. 9; pp. 1373 - 1383
• Main Authors: Bernardo, Camila Hipolito, Bernardes, Veronica Pereira, da Silva, Thiago Elias, de Sousa, Aline Nonato, Taddei, Fabiano Gazzi, Fransozo, Adilson
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-09-2020; Springer Nature B.V
• Subjects: Biomedical and Life Sciences; Cell Biology; Crustaceans; Environmental factors; Frequency distribution; Interspecific; Life Sciences; Microbiology; Original Article; Plant Sciences; Population; Population structure; Sexual maturity; Swimming; Trawling; Zoology; Brazil; Reproductive females; Bycatch; Siri-candeia; Ubatuba
• ISSN: 0006-3088; 1336-9563
• DOI: 10.2478/s11756-019-00399-5

We studied the reproduction and population structure of a population of
Achelous spinimanus
in the region of Ubatuba, Brazil. We collected them monthly, in 2000, in eight sites of different depths (5 to 40 m). The size at the onset of sexual maturity was estimated by the carapace width and the population structure was analyzed based on the size frequency distribution. In total, we collected 402 individuals: 28 juveniles, 105 males and 269 females. In 2000,
A. spinimanus
reproduced continuously and had a single peak in September–October. This timing contrasts with what has been observed in other populations and may be a local strategy to decrease the interspecific competition with other swimming crabs. The individuals of
A. spinimanus
from Ubatuba in 2000 were smaller (16.8–93.5 mm) than those from Fortaleza Bay (near Ubatuba) in 1988–1989 (19.0–97.3 mm). We suggest that intense trawling pressure may have contributed to a reduction in the size of individuals.