Attraction of age-0 red snapper, Lutjanus campechanus, to
areas of reduced bycatch mortality
Stephen T. Szedlmayer
Marine Fish Laboratory, Department of Fisheries and Allied
Aquacultures, Auburn University, 8300 State Highway 104, Fairhope, AL
36532 USA; Phone: 334-990-4858 Fax: 334-990-4840; E-MAIL: sszedlma@acesag.auburn.edu
In 1998, we built 30 4m2 reefs of shell
and 30 4m2 reefs of shell/concrete blocks/bricks, at depths of 17 to
21 m, in the Gulf of Mexico, 14 to 25 km south of Dauphin Island,
Alabama. There were 3 sites, 20 reefs each, placed at 20 m intervals
and alternated from shell to block type. Total mean counts for all red
snapper, Lutjanus campechanus, were significantly different
between reef types, with 14 fish/block reef and 19 fish/shell reef (P
< 0.05). Separated into age-0 and age-1 year classes, few age-0 red
snapper were observed in July, while age-1 were common. In August,
age-0 red snapper reached counts up to 113 fish/reef. There was a
significant interaction effect with age-0 more abundant on shell reefs
at site 1 (mean = 47 fish/reef), and age-1 significantly more abundant
on block reefs at site 3 (mean = 13 fish/reef; p < 0.05). Due to a
hurricane in September 1998, all 1998 reefs were destroyed. In 1999,
we rebuilt all 60 reefs. Counts up to 216 age-0 red snapper were
observed on individual reefs. It appears that these low profile (10
cm) oyster shell reefs can attract very high numbers of age-0 red
snapper, suggesting that shell planting could attract age-0 red
snapper away from areas of intensive trawl fishing, thus enhancing
survival.
|