Reconstructing reciprocal M vectors from length cohort analysis (LCA) of commercial size frequencies of hake, and fine mesh trawl surveys over the same grounds

• Published in: Fisheries research Vol. 41; no. 2; pp. 169 - 175
• Main Authors: Caddy, John F., Abella, Alvaro J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.1999; Elsevier
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; BODY MEASUREMENTS; CHALUTAGE; Commercial size frequencies; Exploitation and management of natural biological resources (hunting, fishing and exploited populations survey, etc.); FILET DE PECHE; FISHING NETS; Fundamental and applied biological sciences. Psychology; Hake; HAKES; Length cohort analysis; M-at-age; MAR MEDITERRANEO; Marine; MEDICION DEL CUERPO; MEDITERRANEAN SEA; MENSURATION CORPORELLE; MER MEDITERRANEE; MERLU; Merluccius; MERLUZA; PESCA A LA RASTRA; REDES DE PESCA; Stock assessment; Surveys; TRAWLING; Italy; Mediterranean Sea; West Mediterranean; Europe; MED, Ligurian Sea; Surveys; Hake; Stock assessment; Length cohort analysis; M-at-age; Commercial size frequencies; Methodology; Estimation; Population structure; Fishing; Trawl; Marine environment; Vertebrata; Population survey; Analysis method; Pisces; Natural biological resources; Body size; Resource management; Merluccius merluccius; Stock
• ISSN: 0165-7836; 1872-6763
• DOI: 10.1016/S0165-7836(99)00015-6

Results of length cohort analysis of commercial landings with fine mesh trawls of small hake from Viareggio, Ligurian Sea, are compared with the size frequency of contemporaneous randomized trawl surveys on the fishing grounds of the same port under two assumptions: (1) constant M; (2) M as a reciprocal function of age obtained from an earlier analysis. The second comparison showed a closer relationship between predicted and actual numbers of individuals on the grounds. A third approach used the same two data sets to find a “best fit” for a reciprocal M-at-age relationship of the type previously described by Caddy. This M vector, and the F-at-age values lead to, appear to be more reasonable than those obtained under “constant M” assumptions.