BIOTIC Species Information for Osilinus lineatus
|Researched by||Nova Mieszkowska||Data supplied by||MarLIN|
|Refereed by||This information is not refereed.|
|Reproductive Season||May to August||Reproductive Location||Water column|
|Reproductive frequency||Annual protracted||Regeneration potential||No|
|Life span||11-20 years||Age at reproductive maturity||1-2 years|
|Generation time||3-5 years||Fecundity||Insufficient information|
|Egg/propagule size||165-250 µm eggs||Fertilization type||External|
|Reproduction Preferences Additional Information||Reproductive Cycle
Sexes are separate but the two sexes cannot be differentiated between by external examination (Fretter & Graham, 1977; Hickman, 1992).
Osilinus lineatus has five stages to its reproductive cycle (Ortonet al., 1956; Desai, 1966). Onset of gonad maturation has been correlated with rising sea temperatures.
Stage I Late summer the gonad is inactive. Both male and female gonads are brown in colour and appear as loose, sac-like structures. Any oocytes present are smaller than 25 µm in diameter.
Stage II. In October the ovaries and testis both take on a greenish hue. Oocytes of up to 50 micrometres are present in females and spermatogonia are present in males.
Stage III. In early January, ovaries and testis are green, oocytes have grown to diameters greater than 50 µm. Spermatocytes and spermatids are present in males.
Stage IV. In February to May, ovaries are deep green in pigment and contain a mixture of mature and immature oocytes. Testis become pink in colour and contain spermatozoa.
Stage V. In May, ovaries are deep green and distended, oocytes are mostly mature. Testis are pink/cream and contain fully active spermatozoa.
Adult Osilinus lineatusmigrate upshore to the high eulittoral zone in early summer prior to spawning. It is thought that this migration brings the animals into a region of higher temperature required for spawning. Desai (1966) found that adults that had migrated furthest upshore were the first to spawn, supporting this idea.
Osilinus lineatus is a broadcast spawner (Underwood, 1972; Hickman, 1992). Males release clouds of white spermatozoa into the water column and females undergo repeated spasms, releasing a few eggs at a time from the mantle cavity into the water (Fretter & Graham 1977). Fertilization occurs externally.
The breeding season is shorter near to northern range limits, with a single spawning period. Towards the centre of the range the breeding season is longer and multiple spawning events occur (Garwood & Kendall, 1985, Bode et al,1986).
Eggs of diameters between 165-250 µm are released individually (Desai, 1966; Fretter & Graham, 1994). The external jelly coating swells on contact with water, making the egg initially buoyant. After 20 minutes the jelly coating disintegrates and the egg sinks. The eggs are lecithotrophic (contain yolk) and provide food for larval development until the larvae hatch as free swimming veligers after 29-30 hours. Six days after fertilization the larva has grown to approximately 1mm in diameter and has fully developed its crawling ability (Desai 1966, Fretter & Graham 1977). Larvae settle on the shore in the low eulittoral zone under boulders and in cracks and crevices.
|Reproduction References||Garwood & Kendall, 1985, Fish & Fish, 1996, Desai, 1966, Hickman, 1992, Bodeet al., 1986, Fretter & Graham, 1994, Orton et al., 1956, Underwood, 1972, Lewis, 1986,|