Download albino ratfish

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NORTHWESTERN NATURALIST
HAZLITT SL, GASTON AJ. 2003. Black Oystercatcher
natal philopatry in the Queen Charlotte Islands,
British Columbia. Wilson Bulletin 114:520–522.
NYSEWANDER D. 1977. Reproductive success of the
Black Oystercatcher in Washington state [thesis].
Seattle, WA: University of Washington. 71 p.
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Larus glaucescens, in the southern Strait of Georgia, British Columbia. Canadian Field-Naturalist
116:564–567.
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K and Butler RW, editors. The ecology and status
of marine and shoreline birds in the Strait of
Georgia, British Columbia. Ottawa, ON: Occasional Paper Number 75, Canadian Wildlife Service. p 118–122.
NORTHWESTERN NATURALIST
89(1)
VERMEER K, EWINS P J, M ORGAN KH, S MITH GEJ.
1992. Population and nesting habitat of American
Black Oystercatchers on the west coast of Vancouver Island. In: Vermeer K, Butler RW, editors. The
ecology and status of marine and shoreline birds
on the west coast of Vancouver Island. Ottawa,
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WOOTTON JT 1992. Indirect effects, prey susceptibility, and habitat selection: impacts of birds on limpets and algae. Ecology 73:981–991.
Pacific WildLife Foundation, Reed Point Marina,
850 Barnet Highway, Port Moody, British Columbia, V3H 1V6 Canada; [email protected]
(RWB); Parks Canada, 2220 Harbour Road, Sidney,
British Columbia V8L 2P6 Canada (TEG). Submitted 8 March 2007, accepted 27 August 2007.
Corresponding Editor: RL Hoffman.
SPRING 2008
89:60–62
FIRST RECORD OF AN ALBINO CHIMAERIFORM FISH,
HYDROLAGUS COLLIEI
JONATHAN CP REUM, CAROLINE E PAULSEN, THEODORE W PIETSCH,
SANDRA L PARKER-STETTER
Key words: Spotted Ratfish, Hydrolagus colliei, Chondrichthyes, albino, Puget Sound, marine fish
Albinism is a genetically inherited condition
in which the pigment protein melanin is either
absent or nonfunctional. Mutations that affect
enzymes involved in the metabolism of melanin can inhibit production, resulting in either
partial or complete loss of coloration. Among
teleost fishes, albino individuals have been reported in numerous species. In a few notable
populations that have evolved in subterranean
environments, relaxation of selective pressures
against albinism has led to the propagation and
fixation of genes associated with the condition
(Wilkens and Strecker 2003; Protas and others
2006). Talent (1973) noted a greater number of
albinos among teleosts than in chondrichthyans and suggested that this difference
might be the result of a lower propensity for al-
AND
binism in chondrichthyans. Or if the frequency
of albinism is the same between fish groups,
the lower abundance of chondrichthyans relative to teleosts may decrease the probability of
observing an albino (Bottaro and others 2005).
Of the chondrichthyan albinos observed, reports have been restricted to rays (Joseph 1961;
Schwartz and Safrit 1977; Brahim and others
1998; Souissi and others 2007) and sharks
(McKenzie 1970; Talent 1973; Smale and Heemstra 1997; Teixeira and de Araujo 2002), and until now no record of an albino chimaeriform has
been reported.
The order Chimaeriformes is composed of 33
extant species and may include as many as 8
additional species that are known but have not
yet been formally described (Didier 2004). Ratfish are distinguished primarily in having hypermineralized non-replaceable tooth plates
and a single gill opening on each side of the
SPRING 2008
GENERAL NOTES
61
FIGURE 1. Spotted Ratfish, Hydrolagus colliei, female, 33 cm total length captured off Whidbey Island, Puget
Sound (specimen ID: UW 115754). Left: Moments after capture (photo by CE Paulsen). Right: Just prior to
fixation (photo by TW Pietsch).
head (Hart 1973; Didier 2004). In Puget Sound,
Spotted Ratfish (Hydrolagus colliei) are the most
abundant bottomfish, constituting approximately half of the bottomfish biomass (Palsson
and others 2005). Individuals are typically dark
brown to grey along the dorsal surface and
have a variable number of white spots.
On 17 June 2007 we captured 1 female albino
Spotted Ratfish measuring 33 cm total length
(Fig. 1), 0.8 km east of Whidbey Island, Washington (UTM coordinates E 459 506 m, N 5306
754 m), using a 400-mesh Eastern otter trawl
lined with 3.2-cm mesh in the codend. The
trawl was deployed from the University of
Washington R/V Centennial. The net had a
headrope length of 21.4 m and a footrope
length of 28.7 m and was towed for approximately 400 m along the 100-m isobath. Upon
capture the female was placed in a container
with flowing seawater. Despite these efforts,
the specimen expired 5 h later and was subsequently frozen at ⫺30⬚C. In September, the
specimen was thawed and fixed using 10% formalin and preserved in 70% ethyl alcohol. The
specimen was archived in the University of
Washington Fish Collection (UW 115754). Because coastal waters of Washington, Oregon,
and British Columbia possess only 1 species of
chimaeriform (Hart 1973), identification of the
specimen as H. colliei was unambiguous. However, to verify that the specimen was not a vagrant Harriotta raleighana (Narrownose Chimaera), which typically occupies deep waters
south of Southern California, we confirmed the
specimen’s identity using the taxonomic key of
Didier (2004).
The albino form of H. colliei differs from pigmented conspecifics in striking ways. Typical-
ly, H. colliei has light green eyes, a dark dorsal
surface with prominent white spots, and dark
grey to brown pectoral and dorsal fins. In the
albino, pectoral and dorsal fins are translucent
along the edge and become increasingly
opaque towards the body. The dorsal surface is
white, with faint textural differences in the skin
demarcating a spot pattern, and the eyes are
red (Fig. 1).
This specimen was captured in a bottomtrawl survey of marine fish distributions in Puget Sound. Over a period of 4 mo from June to
September 2007, the catch from 72 hauls in the
region included 19,938 Spotted Ratfish (CEP,
unpubl. data). In addition, bottom-trawl surveys performed in fall of 2004, and spring and
summer 2005 resulted in the capture of an additional 12,188 Spotted Ratfish (JCPR, unpubl.
data), suggesting that albinism in ratfish is at
least 1 in 33,000 but likely much more rare. The
lack of coloration in albinos has been suggested
to increase susceptibility to predation (Dawson
1967), and it is probable that known predators
of ratfish such as the Spiny Dogfish (Squalus
acanthias) and Six-gill Shark (Hexanchus griseus;
Hart 1973) detect albino ratfish with greater
ease.
Acknowledgments.—Field work was performed by
TE Essington, D Barbee, M Anderson, B Grubb, A
Galloway, B Lee, and D Duggins.
LITERATURE CITED
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NORTHWESTERN NATURALIST
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School of Aquatic and Fishery Sciences, Box
355020, University of Washington, Seattle, Washington 98195 USA. Submitted 23 October 2007,
accepted 26 October 2007. Corresponding Editor:
James Orr.