Diel variation in abundance and size of the seabob shrimp Xiphopenaeus kroyeri (Crustacea, Penaeoidea) in the Ubatuba region, Southeastern Brazil

Sabrina M Simões,Rogerio C Costa,Antonio L Castilho,Adilson Fransozo

doi:10.1590/s0001-37652010000200013

Sabrina M Simões, Rogerio C Costa + Show 2 more

Open Access

https://doi.org/10.1590/s0001-37652010000200013

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Abstract

The objective of the present study was to analyze diel variation in the abundance and size of the seabob shrimp Xiphopenaeus kroyeri in the Ubatuba region, state of São Paulo, during the year 2000. In each season of the year, collections were made in the day and at night on 9 transects at depths ranging from 2 to 40 m. The estimated shrimp amount was of 28,878 individuals. Although the catch rate was higher during the day (15,853 shrimp), this did not differ significantly from the catch at night (13,025). The catch rate was higher in daytime on most transects, but was higher at night at locations where fine and very fine sand predominated. The majority of juveniles were caught during the day. The mean size (CL) was 14.43 +/- 4.02 mm for day and 14.82 +/- 4.28 mm for night samples, and the difference was significant (Student's t-test, df = 2, 429, t = 2.27, p = 0.02). The largest individuals were caught during the night. None of the three models that have been proposed in the literature to account for differences in the diurnal catch pattern of penaeid species can be applied to X. kroyeri. Our results provide evidence that sediment type not only influenced the catch rate in the analyzed periods, but also determined which models might fit the behavior of this species.

Highlights

The tropical marine shrimp fishery, mainly for penaeid shrimps, is a very old activity
Located along the northern coastline of the state of São Paulo, the Ubatuba region is an important area for crustacean research (Mantelatto and Fransozo 2000)
The catch rate of individuals of X. kroyeri was slightly higher in daytime

Summary

Introduction

The tropical marine shrimp fishery, mainly for penaeid shrimps, is a very old activity. Sediment type and depth have been emphasized as major variables affecting the distribution of the penaeid shrimps (Dall et al 1990). The majority of species remains buried during the day and emerge at dusk, i.e., are most active in the period when they are least vulnerable to potential predators (Minello et al 1987, Laprise and Blader 1992, Sogard and Able 1994, Dall et al 1990, Negreiros-Fransozo et al 1999). Penn (1984) noted that the type of substrat can affect burying behavior: in locations with silt and clay sediments, the turbidity of the water may be higher, and here the catch does not differ among the periods. Turbidity is lower and the shrimps are more abundant at night

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