An assessment of chemical contaminants, toxicity and benthic infauna in sediments from the St. Thomas East End Reserves (STEER)

This report contains a chemical and biological characterization of sediments from the St. Thomas East End Reserves (STEER) in St. Thomas, U.S. Virgin Islands (USVI). The STEER Management Plan (published in 2011) identified chemical contaminants and habitat loss as high or very high threats and called for a characterization of chemical contaminants as well as an assessment of their effects on natural resources. The baseline information contained in this report on chemical contaminants, toxicity and benthic infaunal community composition can be used to assess current conditions, as well as the efficacy of future restoration activities. In this phase of the project, 185 chemical contaminants, including a number of organic (e.g., hydrocarbons and pesticides) and inorganic (e.g., metals) compounds, were analyzed from 24 sites in the STEER. Sediments were also analyzed using a series of toxicity bioassays, including amphipod mortality, sea urchin fertilization impairment, and the cytochrome P450 Human Reporter Gene System (HRGS), along with a characterization of the benthic infaunal community. Higher levels of chemical contaminants were found in Mangrove Lagoon and Benner Bay in the western portion of the study area than in the eastern area. The concentrations of polychlorinated biphenyls (PCBs), DDT (dichlorodiphenyltrichloroethane), chlordane, zinc, copper, lead and mercury were above a NOAA sediment quality guideline at one or more sites, indicating impacts may be present in more sensitive species or life stages in the benthic environment. Copper at one site in Benner Bay, however, was above a NOAA guideline indicating that effects on benthic organisms were likely. The antifoulant boat hull ingredient tributyltin, or TBT, was found at the third highest concentration in the history of NOAA’s National Status and Trends (NS&T) Program, which monitors the Nation’s coastal and estuarine waters for chemical contaminants and bioeffects. Unfortunately, there do not appear to be any established sediment quality guidelines for TBT. Results of the bioassays indicated significant sediment toxicity in Mangrove Lagoon and Benner Bay using multiple tests. The benthic infaunal communities in Mangrove Lagoon and Benner Bay appeared severely diminished.

Study of the rocky intertidal communities of central and northern California: Years III and IV

The study objectives are to describe seasonal and successional variation in rocky intertidal community structure; determine the response of rocky intertidal communities to natural and human-induced disturbances and correlate these responses with successional, seasonal, and latitudinal variation; and correlate life history information and oil toxicity data with data from this and other relevant studies. The Year III and IV report is for the third (1987) and fourth (1988) years of a five-year field experimental study investigating two biological assemblages, the Mytilus assemblage and the Endocladia/Mastocarpus papillatus assemblage, that are being studied at six sites along the California coast. Volume I includes the report, Appendix A, and Appendix B. Volume II includes Appendix C. Volume III includes Appendix D. Volume IV includes Appendix E and Appendix F. Volume V includes Appendix G, Appendix H, and Appendix I.

Identification and culture of common diatoms as possible feed for Penaeus monodon

Diatoms were collected from Buyuan Bay, and from the hatchery tanks at Tigbauan, to determine the commonly occurring species, the feasibility of culturing these species, and the potential of these selected species as food for larval P. monodon. The commonly occurring diatoms were identified as Chaetoceros calcitrans, Navicula grimmei, Nitzchia seriata, Nitzchia closterium and Amphiprora sp. These diatoms were isolated and unialgal cultures prepared. Protein content analysis using the micro-Kjildahl method gave the following result: C. calcitrans, 11 . 78%; Nitzchia seriata, 25%; Nitzchia closterium, 30 . 5%; Navicula grimmei, 9 . 06% and Amphiprora sp. 8 . 96%. Feeding experiments were conducted to determine acceptability of the different diatom species and percentage survival of larval stages Z SUB-1 -M SUB-2 . Larvae were placed in 4-l capacity plastic containers with a stocking density of 10/l. The results of several feeding trials using the different mass-produced diatoms are summarized. From the data gathered, C. calcitrans appears to be the most promising candidate as feed for zoea and mysis stages of P. monodon. The average percentage survival of C. calcitrans was 63 . 76% for the 3 trials, and as high as 82 . 22% in the third trial. Comparatively high percentage survival of larvae was also recorded when Nitzchia seriata (48 . 17%) and Nitzchia closterium (67 . 6%) were given as feed, while both Amphiprora sp. and Navicula grimmei gave 0% survival. The poor results with Amphiprora sp. and Navicula grimmei may be due to their low protein content (8 . 96% and 9 . 06%, respectively) and the inability of the larvae to ingest them. Navicula and Amphiprora were observed to cling to the appendages of the larvae and to settle down in the medium making them unavailable to the larvae. Low survival was also noted when frozen C. calcitrans was used (14 . 25%). This may be due partly to the effect of the floculating agent (ALSO SUB-4 . 25 g/l) used in concentrating the diatoms. When protein contents of C. calcitrans, N. seriata and N. closterium are compared, the 2 Nitzchia species have relatively higher protein contents than C. calcitrans and, therefore, could be the more desirable feed candidates. However, few feeding trials were made using Nitzchia so that additional investigations will have to be done on this aspect.