Exploring the decline of oyster beds in Atlantic Canada shorelines: potential effects of crab predation on American oysters (Crassostrea virginica)

Table 5 Mixed effects logistic regression model for the field experiments conducted in Boughton River

Outcome (dead or alive)	Coef.	SE	z	P > \|z\|
Fixed effects
Trial
2	1.64	0.27	6.04	<0.001
Treatment
2	3.15	0.93	3.37	0.001
3	−1.76	0.99	−1.78	0.075
Trial and treatment interaction*				<0.001

Random effect	Estimate	SE
Experimental unit	2.16	0.95
Probability ≥ chibar² ≥ 0.001

Two trials of 18 experimental units with three treatment groups (6 units per treatment). Treatment groups were: Group 1: Oysters in the open environment (reference), Group 2: Oysters in cage with crabs (positive control), and Group 3: Oysters in cage with no crabs (negative control). Trial 1 (reference)—29 July to 12 August, Trial 2—14 August to 28 August 2015
* Overall interaction P value obtained with a Likelihood ratio test (chi² = 97.89)

ISSN: 1438-3888