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

Abstract

SUMMARY: This paper estimates the age and growth of the alfonsino Beryx splendens in the waters around the Izu Islands off the Pacific side of Japan. The samples consist of 250 fish of the landings of the offshore longliners from December 1995 to November 1996 and 10 fish of the coastal longliners in February of 1995. By the surface method using a microscope, a reader counted the number of hyaline and opaque zones on the sagittal otoliths, judged whether the edge was hyaline, and measured the radii from the focus to the outer edge of each hyaline zone. In order to estimate the parameters of the von Bertalanffy’s growth equation representing the overall ages, the age and fork length data and the mean length at 1 year old. In a previous study were used for the maximum likelihood approach. From the results, the rate of readability of the otolith from the offshore samples was 97.6% and that from the coastal samples was 100%. The monthly changes in the frequency of the opaque edge showed that the hyaline and opaque zones were laid down once a year. The hyaline zone began to form from May to July (peaking in August). The ages of the offshore samples for both the sexes ranged from 2 to 23 years, and those of the coastal samples 2 to 5, respectively. The estimated growth curves were expressed by l(t) = 44.4[1–exp{–0.132(t + 3.45)}] for males and l(t) = 45.0[1–exp{–0.150(t + 2.08)}] for females, where l(t) and t denote the fork length (cm) and the age in years, respectively. The issues to be resolved in the future were discussed.

Global and New Caledonian patterns of population genetic variation in the deep-sea splendid alfonsino, Beryx splendens, inferred from mtDNA

“…Some studies made in recent years have helped to improve our understanding of the general biological features of the species, such as reproductive or feeding habits (Lehodey and Granperrin 1996;Adachi et al 2000;Dürr and González 2002;Gonzalez et al 2003). Without genetics data, however, an important part of the necessary information is still lacking, precluding controlled fisheries management.…”

“…Sexual maturity is reached at 2-8 years, however, resulting in low resilience to fishing (Lehodey et al 1997). Catches of splendid alfonsinos are made in the Atlantic (Large et al 2003), Indian and Pacific Oceans (Massey and Horn 1990;Lehodey et al 1997;Adachi et al 2000) since the late-1970s. Beryx spp.…”

Identification of alfonsino and related fish species belonging to the genus Beryx with mitochondrial 16S rRNA gene and its application on their pelagic eggs

“…Several biological features of B. splendens have been documented, including maturity, 2–4 growth, 5–8 distribution of adult fish 9 and spawning grounds 10 . However, other information has not been satisfactorily determined, such as the abundancy, distribution and translocation of pelagic eggs and larvae, and the developmental stage where larvae start moving to the bottom.…”

Microsatellite DNA-based genetic traceability of two populations of splendid alfonsino, Beryx splendens (Actinopterygii: Beryciformes: Berycidae)—Project CELFISH—Part 2

“…Extensive information on the beryciforms has been supplied by Kotlâr (1996) who reported the order to consist of 7 families with 29 genera and 144 species. The alfonsino life span is assessed to average several years, the oldest reported specimen being 23 years old (Adachi et al 2000).…”

“…Extensive information on the beryciforms has been supplied by Kotlâr (1996) who reported the order to consist of 7 families with 29 genera and 144 species. The alfonsino life span is assessed to average several years, the oldest reported specimen being 23 years old (Adachi et al 2000).The nature of alfonsino's migrations (unrestricted or spatially constrained) is not known, nor has the gene fl ow between stocks from various fi shing grounds been followed. According to Lévy-Hartmann et al (2011), the alfonsino shows an extremely high intraspecifi c diversity, which suggests the presence of genetically separate stocks or even populations.…”