Age and growth of the alfonsino Beryx splendens from the waters around Izu Islands

Transcription

1 2007 Age and growth of the alfonsino Beryx splendens from the waters around Izu Islands Seiji Akimoto* Age and growth of the alfonsino Beryx splendens from the waters around Izu Islands were determined by examination of whole otoliths The samples consist of fish were collected in the fishing ground around Izu Islands from September to January The study indicated that one opaque and one hyaline zone were formed annually in sagittal otoliths Growth of B splendens was expressed by the von Bertalanffy asymptotic growth function as Lt = expt + for males and Lt = expt + for females where t is age year and Lt is Fork length mm at age t These two equations were significantly defferent p The results of the present study were compared with those of other researchers who had studied alfonsino Beryx splendens - cm - Adachi et al Adachi et al FL - mm FL - mmtable Fig mm g *

2 Samples collected for growth estimation of alfonsino, Beryx splendens Fishing ground Date Number of fish (length range in mm) Males Females Total Off Boso Pen.(Okinoyama, Tomidashi) 3 Sep Jan ( ) 36 ( ) 48 Off Miyakejima (Sanbon) 6 Jul Sep ( ) 16 ( ) 34 Off Mikurajima (Inanba) 15 Jul Aug ( ) 24 ( ) 51 West of Hachijojima (Nishinose, Nanseise) 27 Jul Jun ( ) 43 ( ) 72 West of Torishima 26 Apr Nov ( ) 30 ( ) 43 Total Sampling locations for Beryx splendens in the fishing grounds around Izu Islands Middle of Japan off Boso Peninsula Okinoyama Tomidashi ; off Miyakejima Sanbon ; off Mikurajima Inanba ; west of Hachijojima Nishinose Nanseise ; west of Torishima VHX- KEYENCE Focus r marginal index Lehodey and Diagram of sagittal otolith showing method used to measure radii r of annuli Wm width of margin; Wa width of last complete annulus Readability categories used for interpretation of sagittal otoliths and weighting coefficients Level of readability Categories Weighting coefficients Clear and unambiguous 1 4 Little or doubt 2 3 Slight dout 3 2 Considerable doubt 4 1 Unreadable 5 0 Grandperrin Fig Marginal index Table

3 Radius of otolith R (mm) R=0.172 FL r 2 =0.722 Marginal index Fork length FL Relationship between otolith radius and fork length of the alfonsino The points and curve show the data and the estimated curve Calendar month Seasonal changes in mean marginal index of sagittal otoliths; both sexes combined Data are represented by means black circle standard deviations Frequencies and percentages of otoliths as a function of readability category, Fork length and sex Fork length Categories in level of readability (mm) No Male % % % % % Total Female Total von Bertalanffy Excel Microsoft ver F FL:mm R:mmR= FL r = Fig Nucleus Table Table mm mm Table marginal index FigMarginal Index Lephodey and Grandperrin Massey and Horn von Bertalanffy Fig Lt = expt + Lt = expt + F mmmmmm mm Table Fig

4 Von Bertalanffy growth curves for males and females Comparison of von Bertalanffy growth parameters for present study with those from other studies in different geographic zones Area L K t 0 Males Females Males Females Males Females Source Japan Around Izu Islands Present study Around Izu Islands Adachi et al. (2000) 14) Off Muroto Promontory Myojin and Ura (2003) 15) New Caledonia Norfolk-Loyalty ridges Lehodey and Grandperrin (1996) 16) New Zealand Palliser Bank Massey and Horn (1990) 17) L asymptotic length; K rate at which L is approached; t 0 age at length = 0 according to von Bertalanffy growth function cm Adachi et al cm Adachi et al

5 Fork length (cm) Fork length (cm) New Zealand (Massey and Horn 1990) Around Izu Islands (Present study) New Caledonia (Lehodey and Grandperrin 1996) Around Izu Islands (Adachi et al. 2000) Off Muroto Promontory (Myojin and Ura 2003) Age (years) New Zealand (Massey and Horn 1990) Around Izu Islands (Present study) New Caledonia (Lehodey and Grandperrin 1996) Off Muroto Promontory (Myojin and Ura 2003) Around Izu Islands (Adachi et al. 2000) Age (years) Comparison of the von Bertalanffy growth curves for B splendens cm cm cm cmf cm cm cm Adachi et al cm cm Fig Adachi et al cm cm Adachi et al mm mm Table Lephodey and Grandperrin

6 Crustacea CephalopodsSalps m cm Adachi et al Busakhin SVSystematics and distribution of the family Berycidae Osteichthyes in the world ocean J Ichthyol Beryx splendens Ikenoue HAge determination by otolith of Japanese alfonsin Beryx splendens with special reference of growth J Tokyo Univ Fish - Beryx splendens Taniuchi T Kanaya T Uwabe S Kojima T Akimoto S and Mitani IAge and growth of alfonsino Beryx splendens from the Kanto District central Japan based on growth increments on otoliths Fish Sci Adachi K Takagi K Tanaka E Yamada S and Kitakado TAge and growth of alfonsino Beryx splendens in the waters around the Izu Islands Fish Sci Lehodey P Grandperrin RAge and growth of alfonsino Beryx splendens over the seamounts off New Caledonia Mar Biol Massey BR and Horn PLGrowth and age structure of alfonsino Beryx splendens from the lower east coast North Island New Zealand NZ J Mar Freshwat Res - -

7 Gonzalez J A Rico V Lorenzo J M Reis S Pajuelo J G Dias M A Mendonca A Krug H M and Phinho M RSex and reproduction of the alfonsino Beryx splendens Pisces Berycidae form the Macaronesian archipelagos J Appl Ichithyol Lehodey P Marchal P and Grandperrin R Modelling the distribution of alfonsino Beryx splendens over the seamounts of New Caledonia Fish Bull Durr J and Gonzalez J AFeeding habits of Beryx splendens and Beryx decadactylus Berycidae off the Canary Islands Fish Res Lalli C M and Parsons T R Vinnichenko VI Vertical Diurnal Migrations of the Slender Alfonsino Beryx splendens Berycidae at the Underwater Rises of the Open North Atlantic J Ichthyol t Beryx splendens