TY - JOUR
T1 - Gut characteristics and assimilation efficiencies in two species of herbivorous damselfishes (Pomacentridae: Stegastes dorsopunicans and S. planifrons)
AU - Cleveland, A.
AU - Montgomery, W. L.
N1 - Funding Information:
Acknowledgements Thanks go to K. Clifton, D.R. Robertson, R. Tapia, and A. Verde for field assistance and logistical support. We thank M. Horn and two anonymous reviewers for substantial improvements to this manuscript. The government of the Republic of Panama and the Kuna people of the Comarca de San Blas permitted field work in San Blas. Animals were collected and studied under Ministerio de Comercio e Industrias permit nos. 0282 and 0292 granted by the Republic of Panama. Use of fishes for this study follows the guidelines of the Northern Arizona University Institutional Animal Care and Use Committee. This research was supported by a Smithsonian Tropical Research Institute Short-Term Fellowship, a Lerner-Gray Grant-in-Aid of Research, a Raney Award from the American Society of Ichthyologists and Herpetologists, and grants from the Houston Underwater Club and P.E.O.
PY - 2003/1/1
Y1 - 2003/1/1
N2 - The morphological and physiological mechanisms by which marine herbivores assimilate energy and nutrients from primary producers and transfer them to higher trophic levels of reef ecosystems are poorly understood. Two wide-ranging Caribbean fishes, the dusky damselfish, Stegastes dorsopunicans, and the threespot damselfish, S. planifrons, defend territories on patch reefs in the Archipelago de San Blas, Republic of Panama. We examined how relative intestine length and retention time influence digestion and absorption of energy and nutrients in these fishes. The dusky damselfish has a relative intestine length (RIL=intestine length/standard length) of 1.2 and a Zihler index {ZI = intestine length (mm)/10[mass(g)1/3]} of 3.4. These values are significantly lower (PRIL = PZI < 0.0001) than those for the threespot damselfish (3.0 and 8.2, respectively). Both RIL and ZI for both species fall well below previously published values for other herbivorous pomacentrids, and may reflect their primary food resource at San Blas (diatoms). Energy-rich diatoms may be easier to digest than refractory macroalgae characteristic of diets of many herbivorous fishes (RIL range: 2-20). Despite differences in RIL and ZI between these two species, gut retention time is the same (P > 0.05) for both dusky (6.6 h) and threespot damselfish (6.5 h). Thus, food travels the length of the threespot damselfish intestine ∼2.5 times faster than it does in the dusky damselfish intestine. Levels of protein, carbohydrate, and lipid are significantly (0.003 < P < 0.030) higher in the feces of dusky damselfish than in the feces of three-spot damselfish, when both species were fed a natural diet of benthic diatoms collected from damselfish territories. This indicates threespot damselfish have a greater nutrient-specific and total assimilation efficiency than do dusky damselfish. Furthermore, when fed an artificial pellet diet, protein absorption efficiency differed significantly (P = 0.014) between species; threespot damselfish absorbed 98.3% of dietary protein, whereas dusky damselfish absorbed 96.4% of dietary protein.
AB - The morphological and physiological mechanisms by which marine herbivores assimilate energy and nutrients from primary producers and transfer them to higher trophic levels of reef ecosystems are poorly understood. Two wide-ranging Caribbean fishes, the dusky damselfish, Stegastes dorsopunicans, and the threespot damselfish, S. planifrons, defend territories on patch reefs in the Archipelago de San Blas, Republic of Panama. We examined how relative intestine length and retention time influence digestion and absorption of energy and nutrients in these fishes. The dusky damselfish has a relative intestine length (RIL=intestine length/standard length) of 1.2 and a Zihler index {ZI = intestine length (mm)/10[mass(g)1/3]} of 3.4. These values are significantly lower (PRIL = PZI < 0.0001) than those for the threespot damselfish (3.0 and 8.2, respectively). Both RIL and ZI for both species fall well below previously published values for other herbivorous pomacentrids, and may reflect their primary food resource at San Blas (diatoms). Energy-rich diatoms may be easier to digest than refractory macroalgae characteristic of diets of many herbivorous fishes (RIL range: 2-20). Despite differences in RIL and ZI between these two species, gut retention time is the same (P > 0.05) for both dusky (6.6 h) and threespot damselfish (6.5 h). Thus, food travels the length of the threespot damselfish intestine ∼2.5 times faster than it does in the dusky damselfish intestine. Levels of protein, carbohydrate, and lipid are significantly (0.003 < P < 0.030) higher in the feces of dusky damselfish than in the feces of three-spot damselfish, when both species were fed a natural diet of benthic diatoms collected from damselfish territories. This indicates threespot damselfish have a greater nutrient-specific and total assimilation efficiency than do dusky damselfish. Furthermore, when fed an artificial pellet diet, protein absorption efficiency differed significantly (P = 0.014) between species; threespot damselfish absorbed 98.3% of dietary protein, whereas dusky damselfish absorbed 96.4% of dietary protein.
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U2 - 10.1007/s00227-002-0916-4
DO - 10.1007/s00227-002-0916-4
M3 - Article
AN - SCOPUS:0038793697
SN - 0025-3162
VL - 142
SP - 35
EP - 44
JO - Marine Biology
JF - Marine Biology
IS - 1
ER -