Avaliação do crescimento, reprodução e explotação do estoque das lagostas espinhosas no Nordeste do Brasil

Abstract

The spiny lobsters Panulirus argus (Latreille, 1804) and Panulirus laevicauda (Latreille, 1817), have been an important economic marine fishery resource in the Northeast Brazil region since 1960. In the mention region the last biological research of the spiny lobster parameters growth and length-at-first maturity was performed several years ago. Due to the importance of these information in the current sustainable fisheries management an updated of the state of the art of the growth and length-at-first maturity is needed and becoming the statements of this work. With this scenario, and due to the importance of the spiny lobster in the Northeast Brazil region the specific objectives of this thesis are: 1) To describe the age and growth of the spiny lobster stock; 2) to test if the current minimum legal landing size protects the spiny lobster female first reproduction; and 3) implement a length-based stock assessment. To achieve these objectives

this thesis describes and chronologically compare biological information of growth and length- at first maturity, employing length frequency distribution as its main analysis tool. The results

indicate the growth parameters for P. argus as fallows: a) males, L∞ = 176.1 and K = 0.277; b) females, L∞ = 139.4 and K = 0.282. In the same way for P. laevicauda: a) males, L∞ = 136.7 and K = 0.460; b) females, L∞ = 118.2 and K = 0.490. On the other side the results of the

logistic regression indicate that the female of P. argus and P. laevicauda reach the length-at- first maturity in the years 1966 with 87,8 mm and 66,2 mm of cephalothorax (CL) length

respectively. Also, the 2018 sampling shows that the P. argus females reach the length-at-first maturity with 96,2 mm and P. laevicauda with 75,2 mm of cephalothorax length (CL). Moreover, the length-based stock assessment displays a high percentage of immature organisms during the years 1966 (59,9%) and 2014 (94,7%) that were harvested before participating in the reproduction season and sampled in the landings. Equally, the results show low percentage of large spiny lobster (≥ 140 mm CL) in the landing sampled in the studied years. As a consequence, the age and growth parameters previously calculated during the 1990s did not include cephalothorax length observation of small (< 25 mm CL) and large spiny lobster (> 125 mm CL) and due this fact a new assessment is needed. In summary both species of spiny lobster reached the length-at-first maturity with larger size during 2018 than in 1966, therefore the current minimum legal landing size does not protect the reproductive female. Consequently, there is evidence of a high percentage of immature P. argus spiny lobsters on landings in the years 1966 and 2018 possibly indicating growth overfishing for the years studied. Besides, in counterpart there is no evidence of recruitment overfishing in those analysed years.