File:American malacological bulletin (1986) (18157346801).jpg

Title: American malacological bulletin
Identifier: americanmal4519861987amer (find matches)
Year: 1983 (1980s)
Authors: American Malacological Union
Subjects: Mollusks; Mollusks
Publisher: (Hattiesburg, Miss. ?) : (American Malacological Union)
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Biodiversity Heritage Library

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O'DOR ET AL: LOCOMOTION AND ENERGETICS OF HATCHLING SQUID 57 4-i
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1n—i—i—i—i—i—i—i—i—i—i—i—i—i—i—i—r200 10 14 18 22 26 Temperature (C) Fig. 1. Temperature effects on development and metabolic rates in newly-hatched squid. Development rates (filled circles) are for /. illecebrosus and are given in stages per day (20 stages divided by the number of days to hatching; staging and some data from O'Dor ef a/., 1982). Oxygen consumptions (open circles) are for L. opalescens from Hurley (1976). Lines are regressions of the form R = B(A)"'". For development, A is 1.0782 (equal to a Q10 of 2.12), B is 0.460 and r is 0.9995. For metabolic rate, A is 1.0879 (equal to a Qi0 of 2.32), B is 123.7 and r is 0.995. they appear to do better at these higher temperatures. The number of viable hatchlings from the egg mass at 26°C was higher than from any mass observed to date, and they ap- peared to be more fully developed at hatching. The buccal mass was fully formed and operational, for example, which was typically seen only several days post-hatch in earlier ex- periments. Records of earlier hatchlings are not precise enough to be sure whether there is really a better coordina- tion of development of all systems at the higher temperatures or whether there was simply a higher proportion of premature hatching at the lower temperatures. In most egg masses at lower temperatures, a fungus develops in the gel after about a week, and as the gel collapses the expanded chorions of the later stages (O'Dor ef a/., 1982) are more easily ruptured causing premature hatching. Whether high temperatures ultimately produce more viable squid depends upon several factors. Premature hatch- ing is one, but if the metabolic rate increases faster than the development rate, high temperatures could produce well- formed, fully developed hatchlings which would, however, lack the yolk reserves to sustain them until they begin to feed. Figure 1 shows the development rate (R,j) over the entire range of temperatures (T), and compares this effect to the change in metabolic rate (Rm) seen in hatchling L. opalescens (Hurley, 1976). R<j is calculated in stages per day based on the day the first swimming stage XX hatchlings appeared: 6, 9, 13 and 16 days at 26, 21, 16 and 13°C, respectively (O'Dor ef a/., 1982). A regression of rate against log temperature gives the following relation when back- transformed: R = B(A)T For development, back-transformed regression coefficients A and B are 1.0782 and 0.46, respectively; this means the time to hatch is approximately halved by a 10°C rise in temperature and that the development rate has a Q10 of 2.1 (1.078210). For metabolic rate, A is 1.0879 and B is 123.7 giv- ing a Q10 of 2.3. Thus, both development and metabolic rates increase similarly with temperature, and there is no major

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