Estimation of saithe Pollachius virens growth rates around the Beryl oil platforms in the North Sea: a comparison of methods

Abstract

Six biochemical indicators of protein synthesis rate and of metabolic rate in white muscle (RNA concentration expressed as mg RNA g-l muscle, pg RNA mg-' protein and mg RNA mg-' DNA; and the activities of the enzymes citrate synthase, cytochrome oxidase and lactate dehydrogenase) were measured in individual saithe Pollachus virens caught withln the Beryl Oilfield in the North Sea on 4 different occasions over a period of 1 yr. These biochemical parameters were compared with values obtained from laboratory growth experiments in order to estimate growth rates of the offshore fish. Seasonal patterns of growth rate were observed for all of these parameters and all indicated higher growth rates in the summer. Mean estimates of growth rate from RNA concentration, RNA:protein, RNA:DNA and citrate synthase activities for each group (i.e. fish caught at the same location and at the same time) were not significantly different. In addition, condition factor (K), caecal-somatic index (CSI) and gall-bladder-liver index (GLI) indicated that feeding/growth rates were highest in summer and lowest in winter. Comparisons between fish caught in the Beryl Oilfield in August 1988 and a sample caught in open sea water above a submerged wreck during the same period, suggested that the fish found around the oil platforms had similar growth rates to those in the open sea.

Ecological Role of an Offshore Industry Artificial Structure

“…It is most likely that the fish biomass recorded here was not produced on the structure but rather the commercially important fishes were attracted to it. Gadus morhua of 0.6 m in length are likely around 3-4 years old (Palakovich Carr and Kaufman, 2009) and Pollachius virens of 1 kg are likely 5-6 years old (Mathers et al, 1992). Pollachius virens is reported to aggregate around offshore oil infrastructure (Mathers et al, 1992;Fujii and Jamieson, 2016) and other structures such as fish farms (Otterå and Skilbrei, 2016) where they typically carry out diurnal vertical migrations.…”

A comparison of RNA concentrations and ornithine decarboxylase activity in Atlantic salmon (Salmo salar) muscle tissue, with respect to specific growth rates and diel variations

“…Mathers et al (1993) found no correlation to either RNA concentration or growth rate for the activities of citrate synthase and lactate dehydrogenase in a laboratory experiment with rainbow trout fry. Significant relationships between RNA concentrations and the activities of the aerobic enzymes cytochrome oxidase and citrate synthase have been found in most cases for field studies with pollock (Mathers et al 1992a;Houlihan et al 1993), but in a laboratory experiment (Mathers et al 1992b) aerobic enzyme activities did not correlate with RNA concentrations, although they were significantly correlated with specific growth rate. In cod, cytochrome c oxidase activity in muscle tissue was linearly related to growth, but a delayed response to refeeding argued against its use as a more sensitive growth index than RNA .…”

“…White muscle is regarded as the best tissue for indicating growth rate of the whole fish, since rates of protein synthesis in that tissue are the closest to that of the whole animal . RNA concentrations in muscle have been compared with the activity of lactate dehydrogenase (LDH), citrate synthase (CS), and cytochrome oxidase with respect to growth rates in pollock (Pollachius virens) (Mathers et al 1992a;Houlihan et al 1993) and rainbow trout (LDH and CS only) . RNA and cytochrome c oxidase activity have also been measured together in white muscle of Atlantic cod (Gadus morhua) .…”

North sea fish and higher trophic levels: a review

“…(4) Biochemical methods MATHERS et al (1992) comparatively applied six biochemical methods (RNA/DNA ratios and 3 enzymatic activities) of growth rate measurements to saithe in the vicinity of oil rigs in the North Sea. They compared experimental results with field values to estimate growth in the field.…”