Publication Date:
2020-07-29
Description:
Feeding and growth rates of tagged individuals and of a captive school of I. illecebrosus , were monitored over a 2-month period on a live fish diet. The daily feeding rate for maintenance is estimated at about 1% of body weight. Average daily feeding rates ranged from 3.6 to 6.7% and average daily growth rates from 1.0 to 1.9% of body weight, both increasing with temperature. Food conversion rates (wet food weight to wet squid weight) ranged from 25 to 36% and conversion efficiency, after allowing for maintenance, ranged from 35 to 51%. These feeding and growth rates are higher than those reported for Octopus vulgaris at comparable temperatures. The maintenance requirement was slightly higher for I. illecebrosus but the conversion efficiency was much lower. Growth rates of I. illecebrosus from field data are well below those for captive animals, indicating that the food supply of the natural population becomes increasingly limiting as the season progresses. Estimates of food consumption by the natural population are higher before July than in the remaining months of the year, and most of the squid biomass results from early season feeding when crustaceans are the principal prey. Cannibalism may be a major food source for the breeding stock late in the season and during migration from coastal waters.
Type:
Article
,
PeerReviewed
Format:
text
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