Reproduction of cutlassfishes Trichiurus spp. from the South China Sea

Abstract

Cutlassfishes, Trichiurus Linnaeus, 1758, are the most important commercial marine fish species of China in terms of weight and they are found in all Chinese waters. However, no study has been conducted on the populations of Trichiurus in the South China Sea. The aim of this study was to investigate the reproduction of the populations of Trichiurus spp. in the South China Sea. In a 12 mo sampling period between December 1996 and November 1997, 1495 specimens of T. lepturus and I.nanhaiensis were collected from Hong Kong coastal waters. Spawning period and reproductive cycle were studied by checking the temporal profile of the Relative Gonadal Index/Gonosomatic Index, and by examining ovaries macroscopically and whole oocytes microscopically. All 3 methods provided sim~lar results: the spawning periods of T, lepturus and T. nanha~ensis were March to June and April to August, respectively. Both species were found to practice group-synchronous spawning and mature females are capable of spawning more than once each spawning season. The mean preanal lengths at sexual maturity of T. lepturus and T. nanhaiensis females were 255 and 282 mm respectively. The sex ratios of both species were significantly different from 1:l among different sampling months, and different age and size ranges.

BIOLOGI REPRODUKSI DAN KEBIASAAN MAKAN IKAN LAYUR (Trichiurus lepturus, Linnaeus) DI SEKITAR PERAIRAN BINUANGEUN, BANTEN

“…Oleh karena jumlah periode pengamatan hanya dilakukan selama 5 bulan sehingga tidak dapat menduga puncak musim pemijahan ikan layur namun dapat menduga pemijahan terjadi beberapa kali dalam setahun. Menurut Kwok & Ni (1999), ikan layur memijah lebih dari sekali dalam musim reproduksi dan menurut Setiawan (2006), musim pemijahan ikan layur (T. lepturus) di selatan Jepang terjadi saat suhu berangsur hangat yaitu sekitar bulan April-Mei dan menurut Wojciechowski (1972) di Mauritania, spesies ikan layur melakukan proses pemijahan pada bulan Mei sampai Oktober.…”

Fecundity and Gonado-somatic Index of Trichiurus lepturus (Linnaeus, 1758) Along the Zamboanga del Norte Coast

“…Comprehensive study on reproductive biology of trichiurus has been studied by Kwok and Ni (1999) in China Seas, Martins and Haimovici (2000) in the South-West Atlantic and Al-Nahdi et al,(2009) in the Arabian sea coast of Oman. Spawning and reproductive cycle were studied by checking the temporal profile of the gonado-somatic index and by examining ovaries macroscopically and whole oocytes microscopically.…”

“…On the other hand gonado-somatic index quantifies the gonad weight and the fish somatic weight (Watton, 1991). The variation in GSI throughout an annual cycle usually indicates the beginning and end of the fish reproductive period, an important component of the fish's life history (Estrada, J. et al, 2000).Comprehensive study on reproductive biology of trichiurus has been studied by Kwok and Ni (1999) in China Seas, Martins and Haimovici (2000) in the South-West Atlantic and Al-Nahdi et al,(2009) in the Arabian sea coast of Oman. Spawning and reproductive cycle were studied by checking the temporal profile of the gonado-somatic index and by examining ovaries macroscopically and whole oocytes microscopically.…”

"Aspectos da pesca e dinâmica de populações do espada, Trichiurus lepturus (Trichiuridae, Teleostei), da costa sudeste-Sul do Brasil"

“…Estudos sobre sua reprodução indicam que T. lepturus apresenta desova prolongada, da primavera ao outono, principalmente no verão, sendo encontrados ovos e larvas principalmente no outono (Munekiyo & Kuwahara, 1984;Sheridan et al, 1984;Haimovici et al, 1994Haimovici et al, , 1996Martins & Haimovici, 1997;Kwok & Ni, 1999;Martins & Haimovici, 2000).…”

“…Munekiyo & Kuwahara (1988) verificaram no Japão, 220mm de comprimento anal para fêmeas e 210mm para machos (1 ano). Kwok & Ni (1999) Os comprimentos retrocalculados são freqüentemente utilizados para estimar os comprimentos em idades raramente observadas (Francis, 1990) comprimento total e peso 380 g, até 102.000 ovócitos para um exemplar de 1373 mm e peso 1595 g, com ovócitos maduros apresentando diâmetros superiores a 2,1mm.…”