Biochemical Effects of Temperature and Nutritive Stress on Mytilus Edulis L.

Abstract

In four experiments mussels were subjected to low food levels (mean 5-3 mg dry weight of cells animal" 1 day" 1 ) and constant temperature (15 °C) for prolonged periods. In the autumn, metabolic rate was low and the energy absorbed was equal to the energy demand: i.e. the animals were in 'energy balance'. In the spring, stress resulted in rapid decline of oxygen consumption, also leading to ' energy balance'. In contrast, in the winter, animals were out of 'energy balance' resulting in utilization of stored reserves.During stress the rate of amino-N efflux formed an important component of the energy budget.At temperatures above ambient in the winter the rate of gametogenesis was increased, which resulted in increased energy demand and high oxygen consumption. If food is scarce, part of this demand is met from stored reserves, primarily protein and carbohydrate. This ensures normal development of gametes in the winter. Later, when vitellogenesis is complete and reserves are depleted, stress results in rapid fall in oxygen consumption.There is a marked seasonal shift from a reliance on carbohydrate as the main energy reserve in the summer to a greater reliance on protein as the main reserve in the winter. I N T R O D U C T I O NIn a previous paper Bayne & Thompson (1970) showed that temperature and nutritive stress resulted in a decline in body condition of mussels, Mytilus edulis, when kept in the laboratory. Both carbohydrate and protein were lost from the body tissues but the losses (as a percentage of the initial values) were greater from the germinal (mantle) than from the somatic (non-mantle) tissues. In spite of the loss of body reserves, M. edulis was able to continue maturation of the gonad during the autumn to spring period. In the early summer, however, when the gametes were fully ripe, stress resulted in a recession of the gonad and a rapid loss of protein from the mantle tissues. A similar decline in condition index and loss of glycogen and protein has been reported for adult oysters, Ostrea edulis, when maintained under hatchery conditions (Gabbott & Walker, 1971).Recently, Widdows & Bayne (1971) have discussed the temperature acclimation of oxygen consumption rate, nitration rate and assimilation efficiency for Mytilus edulis in terms of an energy budget for the whole animal. Mussels were fed in excess of the * Present address: NERC Institute for Marine Environmental Research, Citadel Rd, Plymouth PLi 3AX. 270 P. A. GABBOTT AND B. L. BAYNE maintenance requirement (for acclimated animals) but were kept at temperatures 5°C above ambient. During the acclimation period (14 days) the energy assimilated did not meet the metabolic energy demand and body reserves must, therefore, have been utilized to maintain the energy balance until a new equilibrium was established. Animals maintained at low food concentrations were stressed both during and after temperature acclimation. It is evident that high temperatures and low food levels represent a severe physiological stress for M. edults.In a preceding paper Bay...

Variation in biochemical composition during gonad maturation of the tropical abaloneHaliotis variaLinnaeus 1758 (Vetigastropoda: Haliotidae)

“…In Crassostrea gigas (Hatanaka 1940) and Pinctada martensi (Ashikaga 1948), it was reported that carbohydrate was converted to lipid during gametogenesis. A similar synchrony of glycogen breakdown and vitellogenesis has been recorded for Mytilus edulis by Gabbott & Bayne (1973).…”

Annual variation in condition, respiration and remineralisation ofMytilus edulis L. in the Sound, Denmark

“…As the reproductive effort increases with age and size (Bayne et al, 1983;Thompson, 1984}, it is likely that the mussels in this study were probably too small and/or in a condition which was too poor for any noticeable spawning. Gabbot & Bayne (1973) found in laboratory experiments that Mytilus edulls reabsorbed mature gametes, if the mussels were exposed to nutritive and temperature stress at the time of spawning. Whether the poor condition of the mussels in the present study induced a reabsorption and subsequent catabohsm of mature gamete tissue is questionable, but it is a possibility.…”

“…6). Mussels hving under favourable conditions accumulate carbon, i.e, glycogen, through summer to autumn (Seed, 1969;De Zwaan & Zandee, 1972;Gabbot & Bayne, 1973), and attain a high content of glycogen relative to protein in autumn. The glycogen is catabohzed when food becomes scarce during late autumn and winter (Dare & Edwards, 1975;Bayne & Scullard, 1977;Zandee et al, 1980;Hawkins & Bayne, 1985).…”

“…Instead the condition dechnes during autumn, as do the oxygen uptake and ammonium release, both as a consequence of a decline in food concentration and temperature. The absence of the accumulation of glycogen reserves is detrimental, since the initiation and development of gonads are relying on glycogen reserves (Gabbot & Bayne, 1973;Bayne et al, 1982), which also indicates that gamete production is inhibited in this population. Hence, the population must be recruited from subtidal populations.…”

Histological study of the gonadal development of <i>Ruditapes decussates</i> (L.) (Mollusca: Bivalvia) and its relationship with available food

“…A few studies, such as those for Chlamys septemradiata (Ansell, 1974) and Ostrea edulis (Ruíz et al, 1992), have described the influence of feeding on the development and duration of the reproductive cycle. However, some authors have reported the disadvantageous effects of food shortage on the reproductive activity of certain species (Mytilus edulis and Aequipecten irradians), which may cause the suppression of gonadal development (Sastry, 1968;Gabbott and Bayne, 1973;Bayne et al, 1978).…”