ESTIMATING THE CARRYING-CAPACITY OF A COASTAL INLET FOR MUSSEL CULTURE

Carrying capacity, in the context of mussel culture, may be defined as the stock density at which production levels are maximized without negatively affecting growth rates. This study provides preliminary estimates of carrying capacity for a small (0.5 km2) semi-enclosed coastal inlet located on the eastern shore of Nova Scotia, Canada. The food supply to the system was determined from measurements of tidal exchange and particulate organic matter over the period of May to October 1986. The food demand, or the mussels' ration, was estimated from grazing experiments conducted in the field. Filtration rates were obtained for mussels feeding on the natural particle spectrum, without subjecting the inflowing water to disruptive pump action. Estimates of the mussels' daily ration (11 to 41 mg POM/mussel per day) were lower than those from other field studies, but comparable to laboratory-derived values. Food supply (g POM/week) was divided by food demand (g POM/kg mussels per week) to obtain weekly estimates of carrying capacity for the system. These values ranged from 2.0 to 6.0×105 kg of market-size mussels (>50 mm) depending on temporal variations in the food supply. © 1990.