Temporal variations in biomass and size of seabob shrimp Xiphopenaeus kroyeri (Heller, 1862) (Decapoda: Penaeoidea) on the southern coast of São Paulo state, Brazil

Abstract

Xiphopenaeus kroyeri (Heller, 1862) is the third most common species caught by fishing boats in the state of Sao Paulo, Brazil and production of this shrimp in the Cananeia region located on the southern coast of this state ranks second in the nation. The aim of this study was to investigate the temporal variation of the total biomass and size of X. kroyeri and analyze this variation against environmental factors in order to suggest some information about the best periods to fish this species. Samples were caught monthly from four sampling stations in Cananeia between July 2012 and June 2014 using a fishing boat equipped with otter-trawl nets. Temperature and salinity were monitored using a multiparameter probe, and sediment samples were also taken using a Van Veen-type gripper for particle size analysis. The shrimp were weighed, quantified, and carapace length was measured (mm). In general, the highest total biomass values were recorded when the fishery was closed in the southeast and south regions, and the highest catch of smaller individuals was also observed during this period. In contrast, in November 2013 the fishing is permitted and high biomass composed of large individuals was observed. The monthly biomass showed a positive relationship with sediment texture, because this species prefers very fine sediments to burrow as a defense against predators. FU - FAPESPFundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [Tematico Biota 2010/50188-8, 12/14874-0, 15/15210-6, 15/20382-0]; Brazilian National Council for Scientific and Technological Development (CNPq)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ) [406006/2012-1, 305919/2014-8]; Instituto Chico Mendes de Biodiversidade (ICMBio), SISBIO [23012-1] FX - This paper is part of the Thematic BIOTA-FAPESP (Sao Paulo Research Foundation) multidisciplinary research project, which is intended to produce a fine-scale assessment of the marine decapod biodiversity of the state of Sao Paulo. Financial support for this project was provided by research grants from FAPESP (Tematico Biota 2010/50188-8) and scholarship funding (nos. 12/14874-0 to APFS, 15/20382-0 to LFM and 15/15210-6 to DSS), and from the Brazilian National Council for Scientific and Technological Development (CNPq) (Regular Research 406006/2012-1 and Scholarship PQ No. 305919/2014-8 awarded to RCC). We are also thankful to the LABCAM and NEBECC for their help during fieldwork, especially Dr. Antonio Leao Castilho (Department of Zoology, IBB, UNESP/Botucatu). All the sampling in this study was conducted in compliance with current applicable state and federal laws (authorization from the Instituto Chico Mendes de Biodiversidade (ICMBio), SISBIO No. 23012-1) NR - 33 PU - SOC BRASILEIRA CARCINOLOGIA PI - RIO GRANDE RS PA - LAB CRUSTACEA DOC FURG, AV ITALIA KM 8, CAIXA POSTAL 474, RIO GRANDE RS, CARREIROS 96201-900, BRAZIL