Reproduction of Perna picta (Mollusca: Bivalvia) from the Atlantic coast of Morocco

Abstract

The reproductive cycle of the mussel Perna picta (Born) on the Moroccan Atlantic coast near Rabat was studied by perio&c observations of gonadal sections, dry tissue weights, b~ochemical composition and spatfall in a natural population. The sex ratio was 55:45 in favour of males; n~ussels attained sexual maturity at 22 mm shell length in both sexes. The general pattern of gametogenic activity of P. picta was comparable with that of Mytilus spp. reported from temperate regions. Gonad development began in October and the gonads were ripe in January or February. Spawnings and reconstitution of gametes took place several times between February and May, and the gonads entered the resting stage or showed reduced activity in summer (June to September). Recruitment occurred between May and September. As in Mytilus spp. from temperate regions, there was an inverse relationship between carbohydrate and protein in the storage and utilisation cycles of these 2 components. While carbohydrate reserves accumulated in the tissues during periods of gonadal inactivity (summer and autumn), protein was stored during periods of gonad development (winter). Energy values calculated per g ash free dry tissue weight fluctuated between 22.3 and 24.4 kJ and energy content (kJ ind.-') was maximal in winter and minimal in summer

Population dynamics of the nonindigenous brown mussel Perna perna in the Gulf of Mexico compared to other world-wide populations

“…Spawning ceases below the lower spawning limit of 18°C (Shafee 1989), accounting for the winter cessation of spawning at FP and MP at water temperatures <18 to 20°C, as has also been reported for Moroccan (Shafee 1989) and Algerian (Abada-Boudjema & Dauvin 1995) P. perna populations. In contrast, tropical and subtropical P. perna populations inhabiting waters which do not fall below 18°C tend to spawn sporadically throughout the year (Vélez & Martinez 1967, Carvajal 1969, Lunetta 1969, Benítez & Okuda 1971, Vélez 1971, Acuña 1977, Berry 1978, Lasiak 1986, van Erkom Schurink & Griffiths 1991, with spawning suppressed during summer (Carvajal 1969, Lunetta 1969, Vélez 1971) when water temperatures exceed this species' 28°C upper limit for gametogensis (Vélez & Epifanio 1981).…”

“…This result suggests that organic energy stores accounted for a greater proportion of mean individual tissue AFDW biomass in the 1993 FP cohort which spawned within its first year than in the 1993 MP cohort which did not spawn within its first year of life. Reduction in individual tissue AFDW as a marker for spawning periods has been documented for a number of mytilid species, including Perna perna, by microscopic examination of gonad sections (Baird 1966, Griffiths 1977, Dix & Ferguson 1984, Shafee 1989, van Erkom Schurink & Griffiths 1991 and weight loss in pre-versus post-spawned individuals (Griffiths 1977, Thompson 1979). Spawning, marked by decline in individual tissue AFDW, was initiated in the 1993 FP and 1992 MP cohorts in early spring 1994 as average ambient water temperatures rose to 18-20°C from mid-winter lows of 12-15°C (Fig.…”

“…Population and reproductive dynamics have been described for Perna perna in South Africa (Berry 1978, Crawford & Bower 1983, Lasiak 1986, Lasiak & Dye 1989, van Erkom Schurink & Griffiths 1991, Lasiak & Barnard 1995, Tomalin 1995, northern Africa (AbadaBoudjema et al 1984, Shafee 1989, 1992, Abada-Boudjema & Dauvin 1995, India and Sri Lanka (Appukuttan et al 1989, Indrasena & Wanninayake 1994, Brazil (Lunetta 1969, Marques et al 1991 and Venezuela (Vélez & Martinez 1967, Carvajal 1969, Vélez 1971, Acuña 1977. The highly variable growth rates, life spans and spawning periodicities among different populations of P. perna (Vélez 1971, Berry 1978, Lasiak & Dye 1989, Indrasena & Wanninayake 1994, Tomalin 1995 makes the potential invasive success of this species in North America difficult to assess.…”

Cellular development of the germinal epithelium during the gametogenic cycle of the golden mussel Limnoperna fortunei (Bivalvia: Mytilidae)

“…Other reproductive characteristics of bivalves, including L. fortunei, are that in the female the oocytes protrude toward the ovarian lumen, are not surrounded by a layer of somatic cells and remain connected to the germinal epithelium throughout their development. This connection, referred to as a stalk, is broken when the mature oocytes are released into the luminal compartment of the ovary (Pipe, 1987;Shafee, 1989;Garton & Haag, 1993;Darrigran & Damborenea, 2006;Saucedo & Southgate, 2008). Therefore, it is reasonable to assume that the nutrition of the oocytes occurs through the stalk.…”

“…Thus, various scales (i.e. inactive, developing, maturing, mature, and spent) categorizing gonadal alterations throughout the reproductive cycle are reported in the bivalve literature (see Lubert, 1959;Shafee, 1989;Saucedo & Southgate, 2008;Franco et al, 2011;Boltovskoy et al, 2015 for review). Despite reporting the same event, reproductive cycle scales vary depending The ovarian tubules present a reduced lumen.…”