The physiological ecology of UV-absorbing compounds from the mucus of marine fishes

x, 113 leavesThis dissertation details my investigation into the physiological ecology of UV-absorbing compounds found in the mucus of marine fishes. In a survey of over 200 species of fishes from around the Pacific, I found that approximately 90% of fishes possess mucus that absorbs strongly in the UV. High-performance liquid chromatography of selected mucus confirmed that the UV-absorbing compounds in the mucus are mycosporine-like amino acids, or MAAs. I determined that the mucus of experimentally UV-exposed Thalassoma duperrey absorbs more strongly in the UV than the mucus of those protected from UV by UV-opaque (but visible light transparent) plastic. However, this difference in mucus absorbance only occurs if fish are provided a dietary source of MAAs. Furthermore, I found that males have higher mucus absorbance than females, and females exposed to UV suffer high rates of skin damage. Females also sequester MAAs in their eggs, and may suffer a conflict of interest between providing sunscreen protection for their eggs vs. their own skin. Three coral reef fish species (Canthigaster jactator, Chaetodon multicinctus, and Thalassoma duperrey) were sampled over a depth gradient, and shallow water fish generally had superior sunscreen, both in terms of magnitude and - spectral shifting, as compared with deeper water individuals of the same species. Temperate tidepool sculpins (Family: Cottidae) showed a significant loss of UV-absorbing compounds with increasing north latitude, and overall, fishes from higher tidepools had more sunscreen than fishes from low tidepools. Behavioral experiments with Thalassoma duperrey showed no dietary or UVinduced differences in weight loss or swimming behavior, and the results on shadeseeking behavior were equivocal. Thus, sunscreening compounds seem to be ubiquitous among marine fishes. The correlations I have found between the UV absorbance of mucus and the depth, latitude, or UV exposure of the sampled individual lead me to believe that mucus UV absorbance is an adaptive defense against UV for fishes

Radiant energy distribution of the three treatments used in the spectral experiments.

<p>PAR = photosynthetically active radiation, UVA = ultraviolet-A, and UVB = ultraviolet-B. </p

Correlation between field-measured integrated UV absorbance of cleaner fish <i>Labroides dimidiatus</i> mucus and laboratory-based mucus dry weight-standardized HPLC measurement of mycosporine-like amino acid (MAA) absorbance.

<p>Correlation between field-measured integrated UV absorbance of cleaner fish <i>Labroides dimidiatus</i> mucus and laboratory-based mucus dry weight-standardized HPLC measurement of mycosporine-like amino acid (MAA) absorbance.</p

Mean (± SE) Fulton’s body condition index (K) for freshly caught cleaner fish <i>Labroides dimidiatus</i> and experimental cleaner fish after three weeks of spectral treatment.

<p>None = newly captured cleaners from 3 m depth. PAR only, UVA+PAR, and UVB+UVA+PAR are experimental treatments, which correspond with spectra in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078527#pone-0078527-g001" target="_blank">Figure 1</a>. </p

Mean (± SE) integrated UV absorbance of cleaner fish <i>Labroides dimidiatus</i> mucus in three spectral experiments over three weeks.

<p>Spectral treatments (and lines) correspond with those in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078527#pone-0078527-g001" target="_blank">Figure 1</a>. </p

Mean (± SD) field absorbance of mucus of freshly caught cleaner fish <i>Labroides dimidiatus</i> (n = 36) from 3 m depth, according to wavelength.

<p>Mean (± SD) field absorbance of mucus of freshly caught cleaner fish <i>Labroides dimidiatus</i> (n = 36) from 3 m depth, according to wavelength.</p

Woodwardia harlandii Hook. var. takeoi Masamune

原著和名: ホソバオホカグマ科名: シシガシラ科 = Blechnaceae採集地: 鹿児島県 屋久島 屋久町 安房 (大隅 屋久島 屋久町 安房)採集日: 1964/8/25採集者: 萩庭丈壽整理番号: JH029520国立科学博物館整理番号: TNS-VS-979520備考: 科名変更(瀬戸先生

Net change between ‘before’ (2008–9) and ‘after’ (2014–15) by taxa for herbivores (protected from fishing) and other families (without fishery restriction).

<p>Data points represents the net proportional change in biomass from ‘before’ to ‘after’, and lines present the 95% quantile range (95%QR) of that change. 95%QR not overlapping zero is evidence of a significant difference between time periods, shown as a green square (biomass increase) or red square (biomass decrease). Taxa shown are all those with mean biomass across before and after periods of at least 0.5 g/m², plus a large bodied parrotfish species, <i>Scarus rubroviolaceus</i>, with mean biomass slightly below that level. Within groupings (surgeonfishes, parrotfishes, unprotected families), taxa are ordered by mean biomass from highest to lowest.</p

Trends in benthic cover at KHFMA.

<p>Data shown are annual mean and standard error.</p

Map of Kahekili HFMA, with reef area classified into 6 habitat-strata.

<p>Strata: Deep Aggregate Reef (DAG); Deep Spur and Groove (DSG); Mixed Mid-Depth (MMX); Shallow Aggregate Reef (SAG); and Shallow Spur and Groove (SSG). Further detail on habitat types is given in the Methods section. Numbers 1–12 in the inset of Maui Island represent the location of monitoring comparison sites, where fish (F) and benthic (B) data are available from 2008 to 2015. 1 = Honolua MLCD (F+B); 2 = Kapalua Bay (F); 3 = Mahinahina (B); 4 = Papaula Point (B); 5 = Puamana (B); 6 = Olowalu (B); 7 = Maalaea (B); 8 = Makena/Keawekapu (F); 9 = Molokini MLCD (F+B); 10 = Ahihi-Kinau Natural Areas Reserve System (NARS) (F); 11 = Kanahena Point (B); 12 = La Perouse (F).</p