Date of Award
M.S. in Biological Science
Tamar L. Goulet
Brice P. Noonan
Anemonefishes' obligatory mutualism with sea anemones dictates their occurrence on coral reefs. I examined spatial distribution, settlement, habitat usage, and survival patterns of the two-band anemonefish, Amphiprion bicinctus. In a 300 X 30 m study site off the coast of Israel in the Gulf of Eilat, fish and anemone populations were monitored for 13 censuses from October 1996 to August 1997. Based on size, anemonefish were categorized as adults, juveniles, or settlers. Settlers tended to cluster together but displayed significantly dispersed distributions in relation to adult individual fish and breeding pairs. Adult and juvenile anemonefish associated more with, and exhibited higher survival in, Entacmaea quadricolor. Settlers primarily inhabited Heteractis crispa and exhibited similar survival rates in the two anemone species. From 1997 to 2015, anemone and anemonefish numbers plummeted by 86% and 73%, respectively. In 2015, all 27 remaining anemones were occupied, with most E. quadricolor inhabited by adults. This saturated habitat could hinder new anemonefish individuals from settling. These results indicate that if the anemone population does not recover, the anemonefish could face local extinction. Additionally, due to the sedentary nature of adult anemonefishes, pelagic larval phases represent the only life stage during which dispersal among reef areas may be possible. In order to examine potential dispersal and population genetic patterns of A. bicinctus within the Gulf of Eilat, fin clips were collected from anemonefish near Eilat, Israel and Aqaba, Jordan. DNA sequence data was obtained through restriction-site associated DNA (RAD) sequencing to allow for the identification of single-nucleotide polymorphisms (SNPs). I did not observe any self-recruitment in the Gulf of Eilat based on parentage and relatedness analyses. The Israeli and Jordanian sites were panmictic and also shosignatures of elevated inbreeding levels. While no recent bottleneck was detected, Tajima’s Neutrality Test suggested a population expansion. Such an expansion could be the result of expansion from refugia in the southern Red Sea after the last glacial maximum. The results from both of these studies have management implications for the continued survival of A. bicinctus in the Gulf of Eilat.
Howell, Jacob Seth, "Nemo no more? Spatial demographic and population genetic analyses of the two-band anemonefish, Amphiprion bicinctus, in the Gulf of Eilat, Red Sea" (2016). Electronic Theses and Dissertations. 1272.