"Dinâmica populacional de Scomber japonicus peruanus (Jordán &Hubb, 1925) (Teleostomi: Scombridae) no litoral peruano, no período de 1990 a 2003" / The population dynamics of the scomber japonicus peruanus (Jordan &Hubb, 1925) (Teleostomi: Scombridae) off the Peru Coast, fram 1990 to 2003

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The population dynamics of the Scomber japonicus peruanus (Chub mackerel) was studied based on commercial fishing data obtained monthly from January 1999 to December 2003 off the Peru coast (3°23’S-18°20’S e 72°W-84°W), within the “Tracking of pelagic resources off the Peru coast” project which is being carried out at the Instituto del Mar del Peru – IMARPE. During this period, Sea Surface Temperature data was obtained monthly I n each one of the sampling areas. The analysis of the growth parameters, mortality rates, as well as the recruitment pattern of the Chub mackerel was obtained from commercial fishing data from 1996 to 2003. For stock assessment the time range was from 1993 to 2003. Sea Surface Temperature varied from 13.60°C (2001) to 29.34°C (1998) with minimum values being found in 1996 and 1999-2001 and maximum values in 1992-1993 and 1997-1998. The landing of the Scomber japonicus peruanus species between 1990 and 2003 varied from 8.119 t to 387.659 t, with an average of 122.513 t. The average of the monthly landings varied between 3.274 t and 16.853 t, with higher values registered on November and December 1998 as well as January and March 1999. The maximum positive anomalies of the landings, which varied from 134.985 to 345.137 t, were obtained in 1997 -1999 and in 2001. On the other hand, high negative anomalies were obtained in 1992 (-34.402 t) and 1993 (-32.894 t). The results show that from 1993 to 2003 the mean fork length of the Chub mackerel decreased from 30,50 cm to 26,70 cm, the fork length of the first catch (Cf50) was 26,40 and that recruitment occurred all year, especially during the summer. Between 1996 and 2003, the growth and mortality study of the Chub mackerel showed that the asymptotic body length (Cf∞) and the growth rate values (K) obtained by ELEFAN I and the ones xv registered by the Ford-Walford method were 42.40 cm and 0.40 cm year–1, respectively. The t-zero (length is 0) was –0.37 year–1 and the amplitude (C) 0.40. The Winter Point (Wp) value was 0.60 and the performance index (φ) 2.86. The mean total mortality rate (Z), obtained by analyzing the linearized catch curve and by the Beverton and Holt method, was 2.30 year–1. The rate of fishing mortality (F) was 1.97 year–1 and the exploitation rate 0.86 year–1. The annual rate of natural mortality (M) estimated by the Rikter and Efanov method and by the Pauly equation was 0.50 year–1. The longevity of the Chub mackerel was 7.60 years. The length based cohort analysis and the application of Beverton and Holt s yield per recruit models as well as Thompson and Bell s predictive model, revealed that the Scomber japonicus peruanus is over exploited and nearing it s maximum capacity.

ASSUNTO(S)

stock taxas de mortalidade crescimento scomber japonicus peruanus mortality rates growth el niño e la niña scomber japonicus peruanus el niño and la niña estoque

ACESSO AO ARTIGO

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