• Korean Journal of Ichthyology
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• v.20 no.3
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• pp.173-178
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• 2008

The substrate preferences of juvenile black sea bass Centropristis striata (Linnaeus) was tested in a circular tank (1.5 m diameter${\times}$0.4 m deep) divided into two equal areas of oyster-related (oyster reef and whole oyster shell) and sand substrates. All trials were video taped for 20 min. Tapes were viewed on a monitor and locations of all fish recorded and timed with respect to substrate. $Mean{\pm}SE$ times on oyster shell were $18.1{\pm}2.0min$ (1-fish trial-1) and $17.5{\pm}1.7min$ (5-fish trial-1). $Mean{\pm}SE$ times on sand were $2.0{\pm}1.0min$ (1-fish trial-1) and $2.5{\pm}1.7min$ (5-fish trial-1). Black sea bass juveniles showed a significant preference for oyster reef and shell over sand substrate in single-fish trials (paired t-test, P<0.05) and also in five-fish trials (paired t-test, P<0.05). $Mean{\pm}SE$ times under oyster reefs were $16.6{\pm}2.0min$ in single-fish trials and $10.7{\pm}2.3min$ in five-fish trials. Mean numbers of movements among oyster reefs were $1.1{\pm}1.0$ in single-fish trials and $11.5{\pm}3.1$ in fivefish trials. Fish spent significantly less time under oyster reefs in five-fish trials, compared to single-fish trials (paired t-test, P<0.05) and they moved more frequently in five-fish trials than in single-fish trials (paired t-test, P<0.05). Significantly higher competition for a refuge in five-fish trials may induce less time under oyster reefs as well as frequent movement of black sea bass juveniles on shell substrate.

• Journal of Integrative Natural Science
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• v.4 no.4
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• pp.278-281
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• 2011

We discuss an application of 'restrictions on the entries of the maps in the minimal free resolution' and '$SC_r$-condition of modules', and give an alternative proof of the following result of Foxby: Let M be a finitely generated module of dimension over a Noetherian local ring (A,m). Suppose that $\hat{A}$ has no embedded primes. If A is not Gorenstein, then ${\mu}_i(m,A){\geq}2$ for all i ${\geq}$ dimA.