Patterns of growth, mortality, and size of the tropical damselfish Acanthochromis polyacanthus across the continental shelf of the Great Barrier Reef
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Date
2005
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Show full item recordAbstract
Age-based analyses were used to demonstrate consistent differences in growth between populations of Acanthochromis polyacanthus (Pomacentridae) collected at three distancestrata across the continental shelf (inner, mid-, and outer shelf) of the central Great Barrier Reef (three reefs per distance stratum). Fish had significantly greater maximumlengths with increasing distance from shore, but fish from all distances reached approximately the same maximum age, indicating that growth is more rapid for fish found on outer-shelf reefs. Only one fish collected from inner-shelf reefs reached >100 mm SL, whereas 38−67% of fish collected from the outer shelf were >100 mm SL. The largest age class of adult-size fish collected from inner and mid-shelf locations comprised 3−4 year-olds, but shifted to 2-year-olds on outer-shelf reefs. Mortality schedules (Z and S) were similar irrespective of shelf position (inner shelf:0.51 and 60.0%; mid-shelf: 0.48 and 61.8%; outer shelf: 0.43 and 65.1%, respectively). Age validation of captivefish indicated that growth increments are deposited annually, between the end of winter and early spring. Theobserved cross-shelf patterns in adult sizes and growth were unlikely to be a result of genetic differences betweensample populations because all fish collected showed the same color pattern. It is likely that cross-shelfvariation in quality and quantity of food, as well as in turbidity, are factors that contribute to the observedpatterns of growth. Similar patterns of cross-shelf mortality indicate that predation rates varied little acrossthe shelf. Our study cautions against pooling demographic parameters on broad spatial scales without considerationof the potential for cross-shelf variabilJournal
Fishery BulletinVolume
103Issue/Article Nr
4Page Range
561-573Resource/Dataset Location
http://fishbull.noaa.gov/1034/king.pdfCollections