Ultraviolet-absorbing compounds in the mucus of temperate Pacific tidepool sculpins: variation over local and geographic scales

Abstract

Temperate tidepool fishes of the family Cottidae (Teleostei) display biogeographic distribution patterns that vary with latitude and elevation within the intertidal zone. Middle and high intertidal pool species show a pattern of 'species replacement', with southern species being replaced by northern species at discrete locations along the coast. Lower intertidal pools, on the other hand, are dominated by a single species, Oligocottus snyderi, that occurs over an extremely wide latitudinal range. As a consequence of both latitudinal and elevational patterns, these fish experience variable amounts of ultraviolet (UV, 280 to 400 nm) irradiation both between and within species. The mucus of tidepool sculpins was analyzed by absorbance spectrophotometry to compare concentrations of UV-absorbing compounds in the mucus of fish, with regard to geographic location or intertidal microhabitat. Mucus from northerly fishes absorbed significantly less UV than the mucus of southerly fishes. Overall, mucus from high intertidal pool fishes absorbed significantly more UV than mucus from middle or lower intertidal pool fishes, but differences were not detectable within a site. The mucus spectra of all fish surveyed contained a single UV absorption peak with maximum absorbance (λ max ) in the short-wavelength UVA (UVA = 320 to 400 nm, λ max range = 323 to 331 nm). Compounds with λ max in the UVB (280 to 320 nm) or longer-wavelength UVA (ca. 360 nm) were not found, although these compounds were present in 38 (UVB) and 59% (longer UVA) of tropical species' mucus (138 species surveyed). KEY WORDS: UV · Mycosporine-like amino acid · MAA · Mucus · Oligocottus · Clinocottus Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 263: [169][170][171][172][173][174][175] 2003 damaging effects of UV radiation, particularly shorter UVB (280 to 320 nm) wavelengths, on fishes include cataracts, corneal damage, and epithelial 'sunburn' damage (Bullock 1982, Ahmed & Setlow 1993, Cullen & Monteith-McMaster 1993, Cullen et al. 1994. For fishes, sunburn can be fatal, but different fish species (and even strains within a species) are differentially tolerant of UV exposure (Blazer et al. 1997, Armstrong et al. 2002. The epithelial mucus of coral reef fishes (n = 138 species) contains varying amounts of several 'sunscreen' compounds that absorb both UVB and UVA (320 to 400 nm) radiation (Zamzow & Losey 2002, J. P. Zamzow unpubl.). The UV-absorbing compounds of one species, Thalassoma duperrey, have been identified by high-performance liquid chromatography as the mycosporine-like amino acids (MAAs) palythine (λ max [maxiumum absorbance] = 320 nm), palythinol (λ max = 332 nm), and asterina-330 (λ max = 330 nm, J. P. Zamzow unpubl.). These compounds, along with palythene at λ max = 360 nm, occur in the ocular tissues of coral reef fishes (Dunlap et al. 1989). The UVBabsorbing peak in coral reef fish mucus is presumed to arise from gadusol or deoxygadusol (λ max = 294 to 296 nm at pH > 7), compounds wh...

Effect of UV radiation on habitat selection by Girella laevifrons and Graus nigra (Kyphosidae)

“…In aquatic systems, the direct deleterious effects of ultraviolet radiation (UV) on planktonic organisms, primary production of dissolved organic matter (Tadetti & Sempéré, ), photosynthetic capacity of algae (Helbling et al , ; Watkins et al , ) and the growth, abundance and survival of invertebrates and vertebrates (Jokiel & York, ; Bothwell et al , ; Kiffney et al , ; McNamara & Hill, ; Zamzow, ; Häder et al , ; Nava et al , ) have been well‐documented. Evidence shows that UV radiation affects all components of aquatic trophic webs from primary producers to consumers (Häder et al , ); however, the effects of UV radiation on intertidal organisms are largely unknown.…”

Ultraviolet-absorbing compounds in the mucus of shallow-dwelling tropical reef fishes correlate with environmental water clarity

“…Fishes were collected from 3 sites ( Fig. 1 A sample of mucus was acquired from each individual by gently scraping the dorsal flank surface over an area of approximately 2 cm 2 with a dulled scalpel blade (Zamzow & Losey 2002, Zamzow 2003, 2004, Zamzow & Siebeck 2006. The absorbance of mucus samples was measured following Zamzow & Losey (2002).…”

“…UV absorbance of the mucus of a Hawaiian wrasse decreased with increasing depth of seawater (Zamzow & Losey 2002), and the mucus of high-latitude tidepool sculpins absorbed less UV than that of conspecifics nearer the equator (Zamzow 2003). In laboratory experiments, the mucus of fish that were exposed to full solar UV radiation absorbed far more UV than that of freshly caught individuals, or that of experimental individuals exposed to photosynthetically active radiation (PAR, 400 to 700 nm) alone (Zamzow 2004).…”

“…Shallow-dwelling marine fishes possess UV-absorbing compounds in their mucus, presumably to protect them from harmful UV (Zamzow & Losey 2002, Zamzow 2003, 2004. These UV-absorbing compounds, called mycosporine-like amino acids (MAAs), cannot be synthesized by animals and are obtained by fish through their diet (Mason et al 1998, Shick & Dunlap 2002, Zamzow 2004.…”

Ultraviolet-B Wavelengths Regulate Changes in UV Absorption of Cleaner Fish Labroides dimidiatus Mucus

“…The UV absorbing compounds in fish epithelial mucus have recently been identified as mycosporine-like amino acids (MAAs; [18]), which are acquired from the diet [19,20]. The ability of fish epithelial mucus to absorb UV radiation varies considerably among species [17,18], and correlates with latitude [18,21], water clarity [22] and depth of capture [17,23]. …”