Seasonal variation in the reproductive activity, physiological condition and biochemical components of the brown musselPerna pernafrom the coastal waters of Yemen (Gulf of Aden)

Abstract

-Gametogenic cycle, gross biochemical composition, condition indices and soft tissue caloric value of the brown mussel Perna perna were investigated in the coastal waters of the Gulf of Aden over ten months, to delineate ecophysiological performance of the bivalve. The timing of reproductive activity and seasonal variations of physiological features appear to depend on interaction of environmental (exogenous) and internal (endogenous) factors. Two major spawning events occurred during seasonal monsoons i.e. in late summer (SW monsoon, August-September) and early spring (NW monsoon, February-March), although these differed considerably in relative intensity and the extent of the resulting changes in physiology and body weight. The summer breeding, which was correlated with low water temperature and abundant food, exerted little effect on biochemical constituents, indicating protracted and portioned spawning. Reserve stores (lipids, carbohydrates and proteins) accumulated gradually in the cooler inter-monsoon period of gametogenic quiescence, to provide energy for periods of natural nutritional stress when water temperature increased and primary production diminished. The second spawning in spring was accompanied by a substantial decrease in lipids, carbohydrates and condition indices of the mussels probably due to the release of nutrient-rich gametes in adaptive response to lower food availability in the environment. High reproductive effort presumably induced increased mortality of females, which were strongly outnumbered by males at a ratio of 1.8:1.0. Caloric value of this mussel falls within a range typical for mussel species in other subtropical areas, highlighting the importance of Perna perna as a local food resource and its potential suitability for aquaculture.Key words: Ecological physiology / Gametogenesis / Biochemical composition / Condition / Reproduction / Mollusca / Perna perna Résumé -Nous avons étudié le cycle gamétogénétique, la composition biochimique, les indices de condition et la valeur calorique des tissus mous de la moule, Perna perna (Mytilidae), de la zone côtière du golfe d'Aden et durant 10 mois, afin d'estimer le comportement écophysiologique de ce bivalve. La période d'activité reproductrice et les variations saisonnières des caractéristiques physiologiques semblent dépendre de l'intéraction des facteurs environnementaux (exogènes) et internes (endogènes). Deux périodes principales de ponte se déroulent durant les moussons saisonnières, en fin d'été (mousson de sud-ouest, en août-septembre) et au début du printemps (mousson de nord-ouest, en février-mars), bien que celles-ci soient très différentes en intensité relative et en conséquences sur les changements physiologiques et sur le poids des mollusques. La ponte estivale, qui est corrélée avec une faible température de l'eau et une nourriture abondante, exerce peu d'effet sur les constituants biochimiques, montrant une ponte prolongée et fractionnée. L'accumulation de réserves (lipides, glucides et protéines) est effectuée...

Reproductive Biology and Ecology of the Green Mussel Perna viridis: A Multidisciplinary Approach

“…During the summer and monsoon seasons (May to September), the coastal waters of Bangladesh had very high temperatures together with a faster current speed, low salinity, depleted nutrient concentration, and lower availability of plankton due to heavy rainfall and surface runoff. Although P. viridis showed a positive shift to tolerate higher temperatures [49], the rising temperature had a proven negative impact on reproduction in mussels, as a low concentration of nutrients was observed in the Gulf of Aden due to this high temperature [50]. Extremes of temperature and desiccation lead to the gametes' degeneration and resorption in mollusks [51].…”

Larval and post-larval growth, spat production and off-bottom cultivation of the smooth venus clam Chionista fluctifraga

“…Performance of farmed bivalves can be monitored by determining condition indices. Indices show long‐term changes in the state of nourishment and indicate the effect of environmental changes (Sokolowski, Bawazir, Sokolowska & Wolowicz ). The CI of C. fluctifraga has been verified in adult clams from natural populations (Castillo‐Durán et al .…”

Age, growth, population dynamics and stock status of Perna perna in Omani waters

“…This species is considered endemic to Yemen, southern India, Sri Lanka, Madagascar, the southwestern Indian Oceans along the east coast of Africa, north of Luderiz Bay, the Mediterranean from Gibraltar to the Gulf of Tunis, the central and southwestern Atlantic Ocean along the coasts of Brazil, Uruguay, Venezuela, the West Indies, and recently colonized much of the Texan coast of the Gulf of Mexico (Hicks and Tunnell, 1995;Hicks ., 2001;Sokolowski 2010). The brown mussel in Oman has little economic value due to limited demands by the local people, and is only consumed by local coastal communities where it is prolific.…”

“…This could be due to the fact that shell growth rate in tropical pernids is greater than that found in temperate mytilids (Vakily, 1989;Hicks ., 2001). The species in its native geographical distribution is known for its rapid growth rate which enables the animal to reach a size of 50 -70 mm in 6 -7 months (Chung and Acuna, 1981;Sokolowski , 2010 …”