Growth parameters and mortality rate of the Scomber japonicus peruanus (Jordán & Hubb, 1925) along the Peruvian coast, South Pacific

The growth parameters and the mortality rates of the Scomber japonicus peruanus (Chub mackerel) were studied based on monthly data of frequency of fork length classes obtained from commercial landings off the Peruvian coast from 1996 to 1998. The asymptotic body length and growth rate values obtained by the ELEFAN I (Electronic Length Frequency Analysis) ranged from 40.20 cm to 42.20 cm and from 0.38 to 0.39, respectively. The oscillation amplitude was 0.60; the Winter point values varied from 0.50 to 0.60 and the performance index from 2.79 to 2.84. The total mortality rate of the Chub mackerel obtained by the linearized catch curve oscillated between 1.68 and 3.35. The rate of fishing mortality varied from 1.16 to 2.78 and the exploitation rate from 0.68 to 0.84. The annual rate of natural mortality estimated by the Pauly's method ranged from 0.52 to 0.53. The results obtained allow us to conclude that the longevity of the Chub mackerel was slightly over seven years.

Revisão do gênero Polyrhaphis Audinet-Serville (Coleoptera, Cerambycidae, Lamiinae)

Polyrhaphis Audinet-Serville, 1835, gênero de Lamiinae distribuído entre o México e América do Sul (excluindo o Chile e abaixo da latitude 35°S), é revisado. Três espécies novas são descritas: P. baloupae, procedente da Guiana Francesa; P. lanei, proveniente do Brasil (Amazonas e Pará); e P. peruana, do Peru. Duas espécies são sinonimizadas: P. testacea Lane, 1965 (= P. gracilis Bates, 1862) e P. paraensis [= P. papulosa (Olivier, 1795)]. É designado neótipo para P. papulosa. A autoria de P. horrida [= P. spinosa (Drury, 1773)] é discutida. Cerambyx armatus Voet (1778?) é considerado um nome inválido e Lamia armiger Schöenherr, 1817 (= Polyrhaphis armiger) o nome válido dessa espécie. Polyrhaphis spinipennis Laporte, 1840, é excluída da fauna da Colômbia. Novos registros de distribuição: P. argentina Lane, 1978, para o estado de São Paulo (Brasil); P. batesi Hovore & McCarty, 1998, para o Equador; P. belti Hovore & McCarty, 1998 para o Equador e Colômbia; P. gracilis Bates, 1862, para a guiana Francesa; e P. turnbowi Hovore & McCarty, 1998, em dúvida, para o Peru. É apresentada chave para as espécies do gênero.

Evaluation of the efficacy of hydrated sodium aluminosilicate in the prevention of aflatoxin-induced hepatic cancer in rainbow trout

The use of aluminum silicates for decontaminating animal feed containing aflatoxins has yielded encouraging results in chicken and turkey poults. In contrast, very few studies have tested these substances in aquaculture. In this work, we investigated the efficacy of a trout diet containing 0.5% hydrated sodium aluminosilicate (HSAS) in protecting against contamination with aflatoxin B1. Trout were reared on these diets for one year and the experimental groups were examined monthly for hepatic presumptive preneoplastic and neoplastic lesions. Regardless of the presence of HSAS, all of the fish that received aflatoxin in their diet have shown hepatic lesions indicative of a carcinogenic process, presenting also the development of cancer in some fish. The concentration of HSAS used in this study was ineffective in preventing the onset of hepatic lesions induced by aflatoxin B1 in rainbow trout.

Taxonomic notes on Borgmeiermyia Townsend (Diptera,Tachinidae) with the first host record for the genus

Borgmeiermyia Townsend, 1935 is a small Neotropical genus of Tachinidae (Diptera) with four described species. Brief descriptions are given to the previously unknown females of B. brasiliana Townsend, 1935 and B. paraguayana Sehnal, 1998, and the male of B. peruana Arnaud, 1963. An identification key to the four known species is given, as well as comments on characters with intraspecific variation. Change of depository of the holotype of B. brasiliana from one institution to another is discussed and its current location is given. Also, the first host is recorded for the genus with the occurrence of B. paraguayana para-sitizing Phylloptera aff. ovalifolia Burmeister, 1839 (Orthoptera: Tettigoniidae: Phaneropterinae).