Aspects of the biology of Lutraria lutraria (L.) (bivalvia : Mactracea)

Kerr, Alison Kirsty (1981) Aspects of the biology of Lutraria lutraria (L.) (bivalvia : Mactracea). PhD thesis, University of Glasgow.

Abstract

The life history of a population of Lutraria lutraria in a depth
of 7m at Hunterston, Ayrshire is discussed. Much of the present
population Is thought to have settled in 1967.
The functional morphology of Lutraria is described and related to
its life as a large, deep-burrowing bivalve. Lutraria spawned in late spring and continued to do so through the
summer in 1979 and 1980. Animals became spent in August and
September. Unsuccessful attempts were made to induce spawning in the laboratory.
Artificial fertilization was successful but development did not
proceed beyond the ciliated gastrula stage. Larvae of Lutraria were not identified in plankton samples and
young stages were not encountered in sieved sediment samples. The biochemical cycle of the total animal and five component
parts (gonad and visceral mass, digestive gland, adductor muscle,
siphon and 'other' tissue) is investigated. A marked increase in weight, reflected in an increase in weight
of the component parts, was recorded in Autumn 1979. This is
thought to be related to an exceptional increase in the phytoplankton
at this time. Although a relationship between the biochemical cycle and reproductive
cycle remains uncertain, definite seasonal changes were recorded in
the respiration rate of Lutraria. At 10°C, the maximum rate of a
standard 20g animal was 0.1283m1s 02/g. dry wt./hr. in May 1980
and the minimum rate was 0.O59mls 02/g. dry wt./hr. in October 1980. The effect of temperature on respiration rate was also investigated.
Significant differences were recorded for five experimental
temperatures (10°C, 15°C, 20°C, 25°C and 30 °C) in August and
October but only between two temperatures (10 C and 30 C) in
April. There was a decrease in respiration rate at 30 C in
August and October, but an increase in April. Respiration rate is affected by a reduction in oxygen tension. A
variety of responses were recorded with a small degree of
regulation shown. Individuals of Lutraria were able to survive 48 hours under
anaerobic conditions. In fully oxygenated conditions heart rate ranged from 4-15 beats per
minute with an average of 8 beats per minute. Heart beat was
markedly affected by changes in temperature and oxygen tension,
increasing to a maximum 22 beats per minute at 25 C, and decreasing
to a minimum 2 beats per minute in anaerobic conditions. Heart rate is reduced (12 beats per minute to 5 beats per minute)
on exposure to air. Lutraria exhibits an intermittent pattern of pumping activity.
Under normal conditions 35% of the time is spent pumping and
this Increases as oxygen is reduced (3.00mls 02/litre) to
65% of the time spent pumping.
15. Under normal conditions the respiratory flow varies between
0.382 litres per hour and 1.023 litres per hxir. Adult Lutraria maintain their ability to burrow, albeit slowly.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: Q Science > QH Natural history > QH301 Biology; Q Science > QL Zoology
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Life Sciences > Life Sciences Animal Biology
• Supervisor's Name: Allen, Professor J.A.
• Date of Award: 1981
• Depositing User: Adam Swann
• Unique ID: glathesis:1981-7448
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 22 Jun 2016 07:53
• Last Modified: 22 Jun 2016 07:53
• URI: https://theses.gla.ac.uk/id/eprint/7448