Weijerman et al. Trends in biomass of coral reef fishes, derived from creel surveys in Guam 
245 
Table 3 
Relative contributions of functional groups to the total catch per year, based on data collected during shore-based creel 
surveys conducted by the Guam Division of Aquatic and Wildlife Resources and expanded by the Western Pacific Fisheries 
Information Network of the NOAA Pacific Islands Fisheries Science Center. All values are percentages. Numbers in italic 
type indicate a contribution >15% to the annual total catch. The functional groups are described in Table 1. 
Functional group 
1985 
1986 
1987 
1988 
1989 
1990 
1991 
1992 
1993 
1994 
1995 
1996 
1997 
1998 
1999 
2000 
Bait fishes 
16.4 
6.8 
7.2 
9.1 
9.8 
15.8 
42.2 
12.0 
9.9 
10.1 
13.9 
10.7 
23.6 
3.7 
6.5 
16.5 
Invertebrates 
22.0 
4.4 
3.1 
3.6 
6.8 
5.1 
12.2 
6.0 
8.9 
9.2 
4.8 
2.8 
12.8 
15.4 
9.2 
6.1 
Nonreef-associated fishes 
1.8 
5.2 
7.9 
2.1 
0.8 
1.8 
0.5 
1.8 
2.8 
2.5 
1.6 
0.8 
2.5 
5.3 
2.4 
2.0 
Macroalgae 
3.2 
3.2 
0.1 
0.1 
0.0 
0.0 
0.5 
0.1 
0.3 
0.8 
0.3 
0.0 
11.6 
3.4 
6.6 
0.1 
Invertebrate-consuming fishes 
15.1 
20.3 
19.7 
24.1 
27.4 
19.0 
9.5 
21.8 
23.8 
18.4 
19.8 
22.6 
13.8 
18.9 
12.5 
19.5 
Planktivorous fishes 
1.9 
0.7 
1.1 
0.7 
2.2 
1.5 
0.6 
1.2 
5.2 
1.8 
2.2 
2.5 
1.4 
3.0 
1.1 
2.0 
Coral-consuming fishes 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.1 
0.6 
Detritivorous fishes 
0.1 
0.2 
0.0 
0.0 
0.0 
0.0 
0.0 
0.1 
0.2 
0.4 
0.3 
0.1 
0.1 
0.2 
0.1 
0.3 
Browsers 
22.4 
30.8 
39.0 
40.4 
34.5 
26.3 
16.0 
35.8 
17.0 
29.4 
35.0 
36.2 
19.6 
30.7 
29.0 
30.5 
Grazers 
3.9 
3.9 
9.3 
8.8 
7.7 
12.3 
3.9 
9.6 
7.4 
6.3 
7.6 
10.6 
4.4 
4.4 
4.4 
7.8 
Scrapers 
1.3 
1.2 
0.5 
1.1 
0.2 
0.5 
2.5 
1.7 
2.2 
2.2 
1.7 
1.7 
1.6 
1.5 
4.3 
1.6 
Excavators 
1.8 
0.0 
0.0 
0.2 
0.0 
0.5 
0.9 
0.9 
0.8 
0.7 
1.6 
1.0 
0.4 
2.7 
1.2 
0.8 
Humphead parrotfish 
0.2 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
Humphead wrasse 
0.3 
0.1 
0.2 
0.6 
1.1 
0.1 
0.0 
0.0 
0.0 
0.0 
0.0 
0.5 
0.0 
0.0 
0.0 
0.1 
Benthic piscivores 
1.7 
2.5 
5.2 
2.2 
1.1 
5.4 
2.6 
3.2 
8.1 
4.5 
4.5 
2.3 
2.4 
4.0 
4.4 
5.4 
Mid-water piscivores 
3.0 
3.0 
0.0 
1.6 
3.0 
2.8 
1.6 
1.1 
2.2 
3.2 
2.1 
2.2 
0.2 
0.5 
3.4 
1.3 
Roving piscivores 
4.7 
3.3 
6.8 
5.2 
4.8 
8.9 
7.1 
4.3 
9.6 
3.6 
3.3 
5.9 
5.4 
6.0 
10.5 
5.4 
Rays 
0.0 
0.1 
0.0 
0.2 
0.4 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.1 
0.0 
0.0 
Sharks 
0.0 
14.2 
0.0 
0.0 
0.0 
0.0 
0.0 
0.4 
1.6 
7.0 
1.4 
0.1 
0.4 
0.2 
4.2 
0.1 
2001 
2002 
2003 
2004 
2005 
2006 
2007 
2008 
2009 
2010 
2011 
2012 
Bait fishes 
8.3 
5.5 
5.9 
6.0 
10.7 
11.2 
10.4 
21.1 
47.5 
3.4 
30.1 
72.6 
Invertebrates 
17.4 
3.8 
14.4 
6.9 
20.1 
5.5 
7.8 
2.2 
13.7 
2.9 
1.0 
4.8 
Nonreef-associated fishes 
1.9 
1.2 
5.5 
13.1 
3.5 
2.2 
0.4 
2.3 
2.6 
5.0 
0.6 
2.8 
Macroalgae 
10.3 
0.3 
0.2 
0.1 
0.0 
0.1 
0.1 
0.1 
0.1 
0.3 
0.1 
0.0 
Invertebrate-consuming fishes 
19.7 
20.8 
17.8 
10.0 
20.5 
10.8 
16.2 
7.9 
6.5 
10.2 
15.3 
6.1 
Planktivorous fishes 
0.8 
1.0 
0.9 
3.2 
0.5 
0.7 
0.3 
0.6 
1.4 
1.0 
0.2 
0.2 
Coral-consuming fishes 
0.2 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.1 
0.0 
0.0 
0.0 
3.9 
Detritivores 
2.2 
0.0 
0.0 
0.0 
0.1 
0.3 
2.7 
0.0 
0.0 
0.0 
0.0 
0.0 
Browsers 
16.8 
35.0 
26.1 
22.4 
12.1 
35.9 
25.7 
21.1 
7.4 
46.1 
10.3 
2.9 
Grazers 
5.1 
5.6 
10.3 
9.8 
8.2 
8.4 
5.5 
8.7 
6.9 
20.3 
6.8 
0.3 
Scrapers 
0.6 
1.1 
3.4 
0.9 
2.1 
2.6 
0.9 
4.8 
0.6 
1.3 
1.7 
0.5 
Excavators 
0.7 
1.0 
3.5 
1.4 
0.5 
0.3 
0.1 
0.4 
0.2 
0.1 
0.6 
0.0 
Humphead parrotfish 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
Humphead wrasse 
0.0 
0.0 
0.2 
0.0 
0.0 
0.1 
0.4 
0.0 
0.0 
0.0 
0.0 
0.1 
Benthic piscivores 
2.3 
6.1 
3.1 
4.0 
3.5 
5.4 
6.4 
2.2 
1.2 
0.5 
0.8 
0.5 
Mid-water piscivores 
2.9 
1.3 
1.0 
2.8 
0.8 
0.9 
0.2 
1.8 
0.6 
0.9 
1.6 
0.0 
Roving piscivores 
10.1 
13.6 
6.0 
19.4 
17.2 
9.2 
22.9 
24.2 
11.3 
8.1 
30.9 
5.2 
Rays 
0.0 
0.0 
0.0 
0.0 
0.0 
2.0 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 
Sharks 
0.7 
3.5 
1.8 
0.0 
0.3 
4.3 
0.1 
2.4 
0.0 
0.0 
0.0 
0.0 
hand, increased on average from 5.6% to 17.1% of the 
catch over the same time periods. The available data do 
not include information on fish size; therefore, it is not 
clear whether this increase was a result of increases 
in the seasonal fishery for juvenile jacks or in catches 
of mature jacks. However, because the gear types that 
target juveniles — hook-and-line and cast net — had in- 
creased catches and because catches by gill net, which 
does not target juvenile jacks, dropped by half, it ap- 
pears that the increase in catch of roving piscivores 
was likely due to an increased catch of juveniles. 
Reconstruction of fish biomass by functional group 
Results from initial analysis of unexpanded data, from 
the interviews as part of the shore-based surveys, indi- 
cate that only for the CPUE for hook-and-line fishing 
in regions 1 and 2 on the eastern coast of Guam (for a 
map of the regions used in creel surveys, see Appendix 
2 Figure) was there a difference (P<0.05) between day 
types (weekdays and weekend days), and there was no 
significant difference in CPUE between regions (Ap- 
pendix 5). Therefore, to simplify analysis, we pooled 
