Table 2.

Lionfish population density (fish per 100 m²) on Okaloosa artificial reefs (ARs), Escambia ARs, and northern Gulf of Mexico (nGOM) natural reefs (NRs) during 2016–2018 estimated via remotely operated vehicle surveys. Changes in mean lionfish population density over time were assessed with generalized linear mixed models (GLMMs) with site incorporated as a random effect. Okaloosa AR and Escambia AR GLMMs were fit with a negative binomial error distribution and the nGOM NR model was fit with a Poisson distribution. GLMM outputs show log-linked parameter estimates for mean lionfish population density, 95% confidence intervals (CI) around mean lionfish density, z-score (z), and p-values (P). Hypothesis testing (z- and p-values) were conducted for each model (Okaloosa ARs, Escambia ARs, and nGOM NRs) to evaluate differences in population density on high-density sites (>25 lionfish per 100 m² and with no prior lionfish removals) relative to the intercept (initial sampling date) and low-density sites (<15 lionfish per 100 m² with prior lionfish removals) relative to high-density sites within the same area and sampling date.

Lionfish density model		Sampling date	Density group	Reef sties	Mean density (100 m−2)	95% CI	z	P
Okaloosa ARs	2016	Oct (Intercept)	High	10	27.22	17.69–41.88	15.03	<0.001
	2016	Dec	High	10	23.41	16.88–32.94	−0.87	0.383
	2016	Feb	High	10	24.23	17.42–34.03	−0.67	0.500
	2017	Apr	High	10	25.86	18.51–36.20	−0.28	0.779
	2017	May	High	10	24.77	17.69–34.57	−0.56	0.575
	2017	Oct	High	10	21.78	15.52–30.76	−1.26	0.209
	2018	Mar	High	10	13.88	09.80–19.87	−3.78	<0.001
	2018	Jun	High	10	7.35	05.17–10.34	−7.17	<0.001
	2018	Oct	High	8	5.72	03.81–08.71	−7.61	<0.001
	2016	Dec	Low	8	5.17	02.72–10.34	−4.80	<0.001
	2017	Feb	Low	8	3.98	02.11–07.96	−5.07	<0.001
	2017	Apr	Low	8	6.30	03.15–12.11	−4.02	<0.001
	2017	May	Low	8	7.50	03.88–14.74	−3.63	<0.001
	2017	Oct	Low	8	15.61	08.17–29.97	−1.40	0.161
	2018	Mar	Low	8	18.29	09.36–35.28	−0.53	0.599
	2018	Jun	Low	8	11.94	06.11–23.60	−0.42	0.671
	2018	Oct	Low	8	10.44	05.22–20.87	0.99	0.324
Escambia ARs	2016	June (Intercept)	High	18	18.65	12.41–28.04	14.06	<0.001
	2017	Nov	High	9	31.71	17.90–56.32	1.81	0.070
	2018	May	High	18	8.39	05.22–13.43	−3.32	0.001
	2018	Aug	High	18	6.34	03.92–10.26	−4.42	<0.001
	2018	Dec	High	18	7.27	04.48–11.56	−3.92	<0.001
	2016	Jun	Low	9	8.02	03.92–16.41	−2.30	0.022
	2017	Nov	Low	9	8.56	03.80–19.34	−3.16	0.002
	2018	May	Low	9	5.87	02.85–12.34	−0.94	0.348
	2018	Aug	Low	9	3.04	01.46–06.53	−1.89	0.058
	2018	Dec	Low	9	4.51	02.18–09.46	−1.26	0.208
nGOM NRs	2016	Jul (Intercept)	High	15	0.24	0.15–0.38	−6.06	<0.001
	2017	Oct	High	15	0.35	0.24–0.52	1.98	0.048
	2018	May	High	7	0.29	0.15–0.57	0.54	0.592
	2018	Aug	High	15	0.20	0.13–0.30	−0.88	0.380
	2018	Oct	High	8	0.07	0.03–0.15	−3.11	0.002