Evaluation of modified Sphyrion tags for marking Caribbean spiny lobsters, Panulirus argus
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- The results of monitoring hard corals restored following the installation of telecommunication cables off Hollywood, Florida
- Food-web structure in introduced and native mangrove communities; a Hawaii-Puerto Rico comparison
- Linking habitat change and nutrient dynamics: comparison of food webs and nitrogen fluxes in burrowing shrimp- and oyster-dominated habitats
- Impact of iceberg scouring on benthic assemblages in the Southeastern Weddell Sea, Antarctica
| Evaluation of modified Sphyrion tags for marking Caribbean spiny lobsters, Panulirus argus
Meaghan C. Darcy1,2* and Carrollyn Cox.1 1Florida Fish and Wildlife Conservation Commission, Marathon, FL, USA; 2Marine, Earth, and Atmospheric Sciences Department, North Carolina State University, Raleigh, NC, USA. Mark-recapture studies have been traditionally employed in ecological and fisheries research to provide quantitative estimates on growth, movement, and mortality. Major assumptions of tagging studies are that the tags are permanent and do not effect the physiology and behavior of the animal. External tags have been used in long-term tagging studies and have been studied extensively, but have produced varying results for a variety of crustaceans. We conducted a laboratory study to investigate the suitability of modified Sphyrion tags by examining tag retention and comparing survival and growth rates of tagged and untagged P. argus. Male and female lobsters from two size classes, adults (76-90 mm CL) and large juveniles (61-75 mm CL), were used in the experiment. The lobsters were checked daily for evidence of mortality and ecdysis, and weekly for tag retention. The results show that 73 percent of all tagged individuals, experienced tag loss at the end of 24 weeks. No effect of sex or size is apparent. A three-percent difference in mortality was observed between tagged and untagged individuals. However tagged females of both size classes experienced higher rates of mortality than their untagged female conspecifics. The difference between mean total growth of tagged and untagged lobsters was 0.86mm, with untagged being larger. Females grew substantially less than males for both tagging treatments and grew less than their untagged female conspecifics. This study was conducted during mating season for lobsters, which may have affected mortality and growth of female lobsters. The data indicates that the modified Sphyrion tag may not be suitable for long-term tagging studies or studies being conducted during reproductive periods for large juvenile and adult lobsters.
Donald R. Deis.* 7785 Baymeadows Way, Suite 202, Jacksonville, FL 32256; telelphone (904) 367-8683; facsimile (904) 733-6621; e-mail drdeis@pbsj.com. The installation of five telecommunication cables at a cable station off Hollywood, Florida, caused the dislocation of 160 coral colonies, which were repaired. Monitoring of the repaired coral colonies, as required by the state and local environmental permits, has focused on survivorship. Survivorship has been taken to mean both successfully reattachment to the bottom and the effect of detachment and repair on the overall health of the colony, particularly in light of the decline of overall health of corals worldwide. A factorial experimental design was used to examine the effects of repair on the incidence of disease and mortality in the coral colonies. The experimental design also examined the potential differences between the reef systems, which occurred at different depths, and the five cables. Thirty repaired coral colonies and thirty reference coral colonies were examined at six months (February 2000), one year (August 2000) after repair, and two years (August 2001). ANOVA was used to understand the significance of any differences between the observations. All of the monitored, repaired corals have been found to be secured to the hard bottom reef surface by the repair process. Slightly more bleaching occurred in the one-year monitoring period; however, bleaching was not prevalent in the monitored corals during either period. No significant difference was found in the incidence of bleaching between the restored and the reference corals and between the second and third reefs. A significant difference was noted in the incidence of bleaching between the cables. Documented sources of recent mortality included serpulid (tube) worms, algae, and sponges. No significant difference in the percentage of recent damage was found between the restored and reference corals, between the second and third reefs, or between the five cables during this monitoring period. Year two results are being analyzed. Food-web structure in introduced and native mangrove communities; a Hawaii-Puerto Rico comparisonA. W. J. Demopoulos,* L. A. Crawford, and C. R. Smith. Department of Oceanography, University of Hawaii, Honolulu, Hawaii, USA.Seven species of mangroves were introduced to the Hawaiian Islands from Florida in 1902 to reduce coastal erosion. At present, large portions of low-energy coastlines and stream banks are fringed by the red mangrove, Rhizophora mangle. This species has high dispersal capabilities, broad tolerance, and few natural enemies in Hawaii; as a consequence, the mangrove habitat appears to be expanding rapidly. Prior to the very recent invasion of mangroves, the intertidal zone of Hawaii essentially lacked vascular plants. The introduction of mangroves to intertidal habitats can dramatically alter a variety of ecologically important characteristics, e.g., rates of water flow, sedimentation, and detrital input. Mangroves produce large amounts of tannin-rich, nitrogen-poor detritus that may require special adaptations to digest. In Hawaii, animals are unlikely to have had time to adapt to this unique food source. Therefore, we hypothesized that mangrove detritus would be underutilized by detritivores in Hawaiian mangroves compared to native Puerto Rican mangrove habitats. We collected material from a variety of primary producers and consumers in Hawaii and Puerto Rico mangrove habitats and used stable carbon and nitrogen isotope analyses to evaluate potential carbon sources and trophic levels. Our results indicated that detrivores living within Hawaiian mangroves do not substantially utilize mangrove-derived material as a food source. Instead, a majority of the animals appeared to be a part of a particulate organic matter and benthic-green-algae based food web that included approximately 2 to 3 trophic levels. In contrast, several species from native Puerto Rican mangroves exhibited carbon isotopic values that overlapped with mangrove leaf material, indicating that mangrove detritus supports a small, but distinct detritivore community. Thus, in contrast to native mangrove habitats, Hawaiian mangroves do not appear to be supporting a productive, detritus-based community. Linking habitat change and nutrient dynamics: comparison of food webs and nitrogen fluxes in burrowing shrimp- and oyster-dominated habitats Theodore H. DeWitt* and Peter M. Eldridge. U.S. Environmental Protection Agency, Newport, OR 97365, USA. Endemic thalassinid burrowing shrimps are simultaneously dominant ecosystem engineering species and economic pests within Pacific estuaries. Dense populations of two shrimps (Neotrypaea californiensis and Upogebia pugettensis) commonly occupy >75% of intertidal and shallow subtidal tideflats. As a result of their burrowing, feeding, and burrow-irrigation, the shrimps modify the physical, chemical, and biotic structure of benthic habitats and aspects of overlying waters. These activities bring burrowing shrimp into conflict with oyster culture (Crassostrea gigas) because sediment excavated by the shrimps buries or smothers the oysters, and U. pugettensis may compete with C. gigas for food. Pesticide used to control burrowing shrimp on commercial oyster beds in Washington state creates a patchwork of shrimp-dominated and oyster-dominated habitats. Many impacts of pesticide and oyster culture on estuarine fauna have been characterized, but impacts to ecosystem functions have not been investigated. We used inverse-analysis-based food web models to examine how Upogebia- or oyster-dominated tideflats affect the flux of nitrogen between the tideflat and overlying water column. The food web models were parameterized using new and existing data on community structure, physiology, and feeding ecology of species found on un-farmed tideflats dominated by U. pugettensis and on commercial oyster beds. Separate food web models were constructed for four scenarios: Upogebia-dominated tideflats, and oyster beds sprayed with pesticide 1, 12, and 36-48 months before sampling. Two predictions generated by these models are that 1) Upogebia-dominated tideflats may have greater fluxes of nitrogen between the benthos and water column than oyster-dominated tideflats, and 2) Upogebia-dominated tideflats may sustain greater rates of in-situ primary production than oyster-dominated tideflats because of greater nutrient recycling. Impact of iceberg scouring on benthic assemblages in the Southeastern Weddell Sea, Antarctica Download 184.93 Kb. Share with your friends:
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