Hydrolagus Colliei Research Articles

Mortality Related to Spotted Ratfish (Hydrolagus colliei) in Pacific Harbor Seals (Phoca vitulina) in Washington State

Tissue perforation and penetration by dorsal fin spines of spotted ratfish (Hydrolagus colliei) were responsible for the death of seven harbor seals (Phoca vitulina) in Washington State (USA) between 2006 and 2011. In six animals, necropsy revealed spines or spine parts that had perforated the esophagus or stomach and migrated into vital tissues, resulting in hemothorax, pneumothorax, pleuritis, and peritonitis. In a seventh case, a ratfish spine was recovered from the mouth of a harbor seal euthanized due to clinical symptoms of encephalitis. Gross examination revealed an abscess within the left cerebrum, which was attributed to direct extension of inflammatory infiltrate associated with the ratfish spine. Between 2009 and 2011, spotted ratfish spines were also recovered from the head or neck region of three Steller sea lions (Eumetopias jubatus) and one California sea lion (Zalophus californianus). Ratfish-related trauma appears to be a novel mortality factor for harbor seals in Washington State and could be related to increased ratfish abundance and a shifting prey base for harbor seals.

Evidence of stability in a chondrichthyan population: case study of the spotted ratfish Hydrolagus colliei (Chondrichthyes: Chimaeridae)

Results presented here provide evidence of an exception to the generalization that all chondrichthyan populations are especially vulnerable to exploitation to the extent that they remain at low abundance for a protracted or indefinite duration even after exploitation rates are reduced. Delta log-normal generalized linear models (GLM) and cluster analysis of fishery-independent catch-per-unit-effort (CPUE) data from 1977 to 2006 indicated the presence of at least two distinct stocks of spotted ratfish Hydrolagus colliei off the U.S. West Coast. CPUE of the continental slope and northern continental shelf and upper slope populations did not vary between 1977 and 1995 and increased from 1995 to 2006. On the basis of the timing of these changes, it is likely that both fishing and climate influenced these trends. Sex and size-specific differences in bathymetric distribution, along with the identification of nursery sites, indicate that fishery by-catch could have a significant effect on population growth. These aggregative behaviours, combined with low fecundity, indicate that H. colliei may be vulnerable to irreversible population depletion by fisheries mortality. Temporal abundance trends indicated, however, that their population size has increased significantly within the last decade, a demonstration of population stability. A literature review indicated that there is also evidence for population stability in other chondrichthyans. The paradigm that all chondrichthyan populations fail to rebuild in response to exploitation, therefore, may not be as broadly applicable as previously thought. Thus, it is not necessarily sufficient to make generalizations regarding the vulnerability of chondrichthyans across higher taxonomic scales.

Combining fishing and acoustic monitoring data to evaluate the distribution and movements of spotted ratfish Hydrolagus colliei

Direct and indirect methods have been used to describe patterns of movement of fishes, but few studies have compared these methods simultaneously. We used 20 years of trawl survey data and 1 year of acoustic telemetry data to evaluate the vertical and horizontal movement patterns of spotted ratfish Hydrolagus colliei in Puget Sound, WA, USA. Densities of large ratfish (≥30 cm) were higher at the deepest depths trawled (70 m) during daylight hours, whereas densities were similar across depth zones (to 10 m) at night. Acoustic tracking of ratfish showed distinct diel patterns of movement and activity level; ratfish moved into shallow, nearshore habitats at night from deeper, offshore habitats during the day and made ~3 times more moves at night than day in shallow habitats. Broader spatial patterns depended on where ratfish were tagged: one tag group remained in one general location with few excursions, whereas a second tag group moved within a 20-km band with some individuals moving >90 km. These data will help inform food web models’ abilities to quantify interspecific interactions between ratfish and other components of their community.

Very low pressures drive ventilatory flow in chimaeroid fishes

Chimaera (Holocephali) are cartilaginous fishes with flexible operculi rather than external gill slits, suggesting ventilation occurs in a manner different from other fishes. We examined holocephalan ventilation morphology, behavior, and performance by anatomical investigations, high-speed video, and in vivo pressure measurements from the buccal and parabranchial cranial cavities in Hydrolagus colliei and Callorhinchus callorynchus. Ventilatory modes ranged from quiet resting breathing to rapid "active" breathing, yet external cranial movements-excepting the passive movement of the opercular flap-were always extremely subtle, and pressures generated were one to two orders of magnitude lower than those of other fishes. To explain ventilation with such minimal pressure generation and cranial motion, we propose an "accordion" model, whereby rostrocaudal movement of the visceral arches drives pressure differentials, albeit with little lateral or ventral movement. Chimaeroids have comparatively large oropharyngeal cavities, which can move fluid with a smaller linear dimension change than the comparatively smaller cavities of other fishes. Orobranchial pressures are often less than parabranchial pressures, suggesting flow in the "wrong" direction; however, the long gill curtains of chimaeroids may passively restrict backflow. We suggest that constraints on holocephalan jaw and hyoid movements were compensated for evolutionarily by novel visceral arch mechanics and kinematics.

Body fluid osmolytes and urea and ammonia flux in the colon of two chondrichthyan fishes, the ratfish, Hydrolagus colliei, and spiny dogfish, Squalus acanthias

The present study has examined the role of the colon in regulating ammonia and urea nitrogen balance in two species of chondrichthyans, the ratfish, Hydrolagus colliei (a holocephalan) and the spiny dogfish, Squalus acanthias (an elasmobranch). Stripped colonic tissue from both the dogfish and ratfish was mounted in an Ussing chamber and in both species bi-directional urea flux was found to be negligible. Urea uptake by the mucosa and serosa of the isolated colonic epithelium through accumulation of 14C-urea was determined to be 2.8 and 6.2 fold greater in the mucosa of the dogfish compared to the serosa of the dogfish and the mucosa of the ratfish respectively. Furthermore, there was no difference between serosal and mucosal accumulation of 14C-urea in the ratfish. Through the addition of 2 mM NH 4Cl to the mucosal side of each preparation the potential for ammonia flux was also examined. This was again found to be negligible in both species suggesting that the colon is an extremely tight epithelium to the movement of both urea and ammonia. Plasma, chyme and bile fluid samples were also taken from the agastric ratfish and were compared with solute concentrations of equivalent body fluids in the dogfish. Finally molecular analysis revealed expression of 3 isoforms of the urea transport protein (UT) and an ammonia transport protein (Rhbg) in the gill, intestine, kidney and colon of the ratfish. Partial nucleotide sequences of the UT-1, 2 and 3 isoforms in the ratfish had 95, 95 and 92% identity to the equivalent UT isoforms recently identified in another holocephalan, the elephantfish, Callorhinchus milii. Finally, the nucleotide sequence of the Rhbg identified in the ratfish had 73% identity to the Rhbg protein recently identified in the little skate, Leucoraja erinacea.

How to build a pectoral fin: functional morphology and steady swimming kinematics of the spotted ratfish (Hydrolagus colliei)

Aquatic flight is the primary locomotor mode for many animals, including penguins and other diving birds, turtles, and fishes, where labriform and rajiform swimming have been the focus of much interest. However, despite its interesting phylogenetic placement, little is known about the aquatic flight of the sister lineage to the elasmobranchs, the chimaerids. This study investigates the pectoral fin morphology of the spotted ratfish ( Hydrolagus colliei (Lay and Bennett, 1839)) as a possible factor underlying the kinematics of their steady swimming by comparing muscle mass, distribution, and abductor to adductor ratio with those of a closely related shark ( Squalus acanthias L., 1758). Despite fundamental differences in swimming mode, abductor to adductor muscle ratio did not differ between species (P = 0.49). However, the muscle ratio in the spotted ratfish was similar to the range determined in other flapping labriform swimmers. Ratfish had larger, distally placed pectoral fin muscles relative to body size than dogfish (P < 0.0001) possibly aiding in fine control. Stroke amplitude remained constant across body size (P = 0.26) and relative swimming speed (P = 0.23) in the ratfish, whereas the downstroke was significantly faster than the upstroke (P = 0.006). The similar muscle ratio, despite differences in stroke phases, may be explained by physiological or in vivo recruitment differences between abductors and adductors in the ratfish.

Nuevos ejemplares y nuevos registros de peces cartilaginosos (Vertebrata: Chondrichthyes) de la costa del Pacífico mexicano

New specimens and new records of occurrence for 10 species of chondrichthyan (elasmobranch and chimaeroid) fishes previously unknown or little documented for the continental shelf of the Mexican Pacific are reported. This contribution provides the first record of Centroscyllium nigrum, Isurus paucus, and Bathyraja trachura for the Mexican Pacific, as well as new specimens of Hydrolagus colliei, Hexanchus griseus, Echinorhinus cookei, Pseudocarcharias kamoharai, and Raja velezi for the western coast of the Baja California Peninsula, including the intermediate record within the known distribution range for Apristurus kampae, and the southernmost record for Raja inornata.

Assessment of the dorsal fin spine for chimaeroid (Holocephali: Chimaeriformes) age estimation

Previous attempts to age chimaeroids have not rigorously tested assumptions of dorsal fin spine growth dynamics. Here, novel imaging and data-analysis techniques revealed that the dorsal fin spine of the spotted ratfish Hydrolagus colliei is an unreliable structure for age estimation. Variation among individuals in the relationship between spine width and distance from the spine tip indicated that the technique of transverse sectioning may impart imprecision and bias to age estimates. The number of growth-band pairs observed by light microscopy in the inner dentine layer was not a good predictor of body size. Mineral density gradients, indicative of growth zones, were absent in the dorsal fin spine of H. colliei, decreasing the likelihood that the bands observed by light microscopy represent a record of growth with consistent periodicity. These results indicate that the hypothesis of aseasonal growth remains plausible and it should not be assumed that chimaeroid age is quantifiable by standard techniques.

Maturity, fecundity, and reproductive cycle of the spotted ratfish, Hydrolagus colliei

Size at maturity, fecundity, and reproductive periodicity were estimated for the spotted ratfish, Hydrolagus colliei (Lay and Bennett, 1839), off the coast of California, Oregon, and Washington. Maximum body size and size at median maturity were greater for females than males. Skeletal muscle concentrations of the steroid hormones testosterone (T) and estradiol (E2) predicted similar, but slightly smaller sizes at maturity than the morphological criterion. Stage of maturity for males was estimated identically using internal organs or external secondary sexual characters, thus allowing non-lethal maturity assessments. Size at median maturity was greater north of Point Conception for females, and north of Cape Mendocino for males. Peak parturition occurred from May to October, with increased concentrations of E2 in skeletal muscle of females correlating with ovarian recrudescence during November to February. No significant seasonal trends in female T were apparent, but mean female 11-ketotestosterone (11KT) was 300% greater in April than any other month during the parturition season. There was a marginal evidence for increased number and size of ova with maternal size. Extrapolation of the hypothesized 6 to 8-month egg-laying season to observed mean parturition rates of captive specimens yielded an estimated annual fecundity of 19.5–28.9 egg cases. Differences in fecundity among higher taxonomic classifications of chondrichthyans were detected with chimaeriform fishes more fecund than lamniform, myliobatiform, squaliform, and rhinobatiform fishes, and less fecund than rajiform fishes.

Correction for Huber et al. , Hard prey, soft jaws and the ontogeny of feeding mechanics in the spotted ratfish Hydrolagus colliei

Correction for ‘Hard prey, soft jaws and the ontogeny of feeding mechanics in the spotted ratfish Hydrolagus colliei ’ by Daniel R. Huber, Mason N. Dean and Adam P. Summers (J. R. Soc. Interface 5 , 941–952. (doi: 10.1098/rsif.2007.1325 )). On page 948, figure 7( b ) was printed incorrectly. The correct version of figure 7 is printed below.

Cranial muscle homology across modern gnathostomes

Imprecise usage of terminology can lead to confusion when trying to compare cranial musculature between taxa from different higher-order groups. The present study aimed to present hypotheses of muscle homology between taxa from four modern gnathostome groups: Actinopterygii (Amia calva), Sarcopterygii (Latimeria chalumnae), Elasmobranchii (Squalus acanthias, Chlamydoselachus anguineus), and Holocephali (Hydrolagus colliei). Muscle homologies are hypothesized based on topological data taken from the anatomical literature and supplemented by new observations of Hydrolagus colliei. Hypothesized muscle groups are tested for congruence against accepted gnathostome phylogeny. From these data, eight muscle groups are identified that are unambiguously homologous across all taxa examined. Four more muscle groups are found to be homologous across a majority of the taxa. Twelve muscle groups are hypothesized to be basal across all gnathostomes. A muscle in Hydrolagus previously called both a geniohyoideus and interhyoideus is here renamed ‘mandibulohyoideus’ to reflect its apomorphic condition. The presence of coracomandibular muscles in all groups supports the hypothesis that basal jaw depression systems in gnathostomes were not linked to hyoid movement, but independently operated by this muscle. The study also offers new insight into muscle reconstruction in fossil groups (Placodermi).

Abundance Trends for <em>Hexanchus griseus</em>, Bluntnose Sixgill Shark, and <em>Hydrolagus colliei</em>, Spotted Ratfish, Counted at an Automated Underwater Observation Station in the Strait of Georgia, British Columbia

Recordings from a time lapse video monitoring station on a shallow rocky reef in the Strait of Georgia, British Columbia, revealed a steep and continuous decline in the occurrence of Hexanchus griseus (Bluntnose Sixgill Shark) between 2001 and 2007, with relative abundance in 2006 and 2007 less than 1% of that in 2001. The relative abundance of another chondrichthyan, Hydrolagus colliei (Spotted Ratfish), decreased to 15% of 2004 levels in 2005 and 2006 and remained below 25% in 2007. There is no compelling explanation for these decreases. Over the past 25 years water temperatures have increased in the Strait of Georgia and there have been a number of El Niño warm water events, but diver observations of H. griseus at this site over the same time period give no indication of prior changes in abundance. Neither species is targeted by a fishery, but injuries, possibly related to hooking and entanglement, observed in 28% of individually identified H. griseus suggests this species may be taken locally as bycatch.

Uniform strain in broad muscles: active and passive effects of the twisted tendon of the spotted ratfish Hydrolagus colliei

A muscle's force output depends on the range of lengths over which its fibers operate. Regional variation in fiber shortening during muscle contraction may translate into suboptimal force production if a subset of muscle fibers operates outside the plateau of the length-tension curve. Muscles with broad insertions and substantial shortening are particularly prone to heterogeneous strain patterns since fibers from different regions of the muscle vary in their moment arms, with fibers further from the joint exhibiting greater strains. In the present study, we describe a musculotendon morphology that serves to counteract the variation in moment arm and fiber strains that are inherent in broad muscles. The tendon of the anterior jaw adductor of the spotted ratfish Hydrolagus colliei is twisted such that the distal face of the muscle inserts more proximally than the proximal face. Using quantitative geometric models based on this natural morphology, we show that this inversion of insertion points serves to equalize strains across the muscle such that at any gape angle all fibers in the muscle are operating at similar positions on their length-tension curves. Manipulations of this geometric model show that the natural morphology is ;ideal' compared to other hypothetical morphologies for limiting fiber strain heterogeneity. The uniform strain patterns predicted for this morphology could increase active force production during jaw closing and also decrease passive resistance to jaw opening. This divergence from ;typical' tendon morphology in the jaw adductors of H. colliei may be particularly important given the demands for high force production in durophagy.

Hydrolagus mccoskeri sp. nov., a new species of chimaeroid fish from the Galápagos Islands (Holocephali: Chimaeriformes: Chimaeridae)

A new species of chimaeroid, Hyd rolagus mccosker i sp. nov., is described from the Galápag os Islands. This species represents the second member of the family Chimaeridae known from the eastern equatorial Pacific. It can b e distinguis hed from its congeners by a combination of the following characters: small head with short, blunt snout; preopercu lar and oral lateral line canals branching from the same node off the infraorbital canal and sharing a short common b ranch; dorsum medium brown with numerous narrow, shar ply delineated circular and elongate white blotches; ventrum white to tan with extremely fine brown mottl ing. The species is compared to Hyd rolagus n ovaezealandiae and Hyd rolagus colliei , the most similar congeners in color pattern and morphology.

Errata for 120(2): table of contents and 235-236; and 120(3): table of contents

Errata: The Canadian Field-Naturalist 120(2)Table of contents outside back cover:Conservation evaluation of Dwarf Wolly-heads, Psilocarphus brevissimus var. brevissimus, in CanadaGEORGE W. DOUGLAS, JENIFER L. PENNY, and KSENIA BARTON“Wolly-heads” should read Woolly-heads.Article page 235:First record of a River Otter, Lontra canadensis, captured on the northern coast of AlaskaSHAWN P. HASKELLIn abstract and citation “Lutra“ should be Lontra.Errata: The Canadian Field-Naturalist 120(3)Table of contents outside back cover:Recent invasion, current status, and invasion pathway of European Common Reed, Phragnites australis subspecies australis, in the southern Ottawa DistrictPAUL M. CATLING and SUSAN CARBYN“Phragnites“ should read Phragmites.Pacific Hagfish, Eppptatretus stoutii, Spotted Ratfish, Hydrolagus colliei, and scavenger activity on tethered carrion in subtidal benthic communities off western Vancouver IslandSARAH DAVIES, ALI GRIFFITHS, and T. E. REIMCHEN“Eppptatretus“ should read Eptatretus.

Pacific Hagfish, <em>Eptatretus stoutii</em>, Spotted Ratfish, <em>Hydrolagus colliei</em>, and Scavenger Activity on Tethered Carrion in Subtidal Benthic Communities off Western Vancouver Island

The influence of pelagic carrion food falls on marine benthic scavenging communities was investigated at two depths (10 m, 50 m) in Barkley Sound, west Vancouver Island, British Columbia from 12 May to 4 June, 2003. A remotely operated vehicle (ROV) equipped with video cameras was used to monitor anchored carrion (15 kg pig leg) during daylight and darkness. The videos were subsequently analyzed for species diversity, abundance and the intensity of scavenging. At 10 m, Redrock Crab (Cancer productus) and Kelp Greenling (Hexagrammos decagrammus) dominated, while at 50 m, Spot Shrimp (Pandalus platyceros), Spotted Ratfish (Hydrolagus colliei) and Pacific Hagfish (Eptatretus stoutii) were the dominant species, most of which were nocturnal. Hagfish were the major consumers of the carrion and after 23 days, no soft tissues remained at 50 m while 40% remained at 10 m. Within 24 hours of the carrion deployment, two of eleven ratfish succumbed, probably due to the direct clogging effects of hagfish mucus on the respiratory apparatus of the ratfish. These field observations are consistent with laboratory results suggesting high efficacy of hagfish mucus in competitive interactions.

Metabolic organization of the spotted ratfish,Hydrolagus colliei (Holocephali: Chimaeriformes): insight into the evolution of energy metabolism in the chondrichthyan fishes

The metabolic organization of a holocephalan, the spotted ratfish (Hydrolagus colliei), was assessed using measurements of key enzymes of several metabolic pathways in four tissues and plasma concentrations of free amino acids (FAA) and non-esterified fatty acids (NEFA) to ascertain if the Holocephali differ metabolically from the Elasmobranchii since these groups diverged ca. 400 Mya. Activities of carnitine palmitoyl transferase indicate that fatty acid oxidation occurs in liver and kidney but not in heart or white muscle. This result mirrors the well-established absence of lipid oxidation in elasmobranch muscle, and more recent studies showing that elasmobranch kidney possesses a capacity for lipid oxidation. High activities in oxidative tissues of enzymes of ketone body metabolism, including D-beta-hydroxybutyrate dehydrogenase, indicate that, like elasmobranchs, ketone bodies are of central importance in spotted ratfish. Like many carnivorous fishes, enzyme activities demonstrate that amino acids are metabolically important, although the concentration of plasma FAA was relatively low. NEFA concentrations are lower than in teleosts, but higher than in most elasmobranchs and similar to that in some "primitive" ray-finned fishes. NEFA composition is comparable to other marine temperate fishes, including high levels of n-6 and especially n-3 polyunsaturated fatty acids. The metabolic organization of the spotted ratfish is similar to that of elasmobranchs: a reduced capacity for lipid oxidation in muscle, lower plasma NEFA levels, and an emphasis on ketone bodies as oxidative fuel. This metabolic strategy was likely present in the common chondrichthyan ancestor, and may be similar to the ancestral metabolic state of fishes.

Assemblage Structure of Eastern Pacific Groundfishes on the U.S. Continental Slope in Relation to Physical and Environmental Variables

AbstractWe analyzed data from the National Marine Fisheries Service continental slope trawl surveys (1999–2002) to examine patterns in eastern Pacific groundfish assemblage structure in relation to longitude, latitude, depth, temperature, and interannual variation. The slope surveys spanned approximately 32–48°N and 200–1,200‐m depths. We focused on the 26 most abundant species, which made up more than 95% of the catch in terms of biomass. Assemblage structure was strongly correlated with depth and latitude. For the most part, changes in assemblage structure appeared to be fairly continuous, although there were more‐abrupt changes at approximately 500–600 m and in the vicinity of Point Conception and Cape Mendocino, California, and Cape Blanco, Oregon. There was also an interaction between depth and latitude; more northerly sites had deeper scores on the canonical axes than did more southerly sites of comparable depth. Shallower sites also showed more variation in assemblage structure with latitude than did deeper sites. We were able to identify five assemblages on the continental slope. Pacific grenadiers Coryphaenoides acrolepis, giant grenadiers Albatrossia pectoralis, deepsea soles Embassichthys bathybius, longspine thornyheads Sebastolobus altivelis, California slickheads Alepocephalus tenebrosus, and roughtail skate Bathyraja trachura formed a deepwater assemblage with a broad latitudinal range. Southern species that inhabited very shallow waters included splitnose rockfish Sebastes diploproa, spotted ratfish Hydrolagus colliei, English soles Parophrys vetulus, stripetail rockfish Sebastes saxicola, chilipeppers Sebastes goodei, and shortbelly rockfish Sebastes jordani. Shallow‐water, midlatitude species included spiny dogfish Squalus acanthias, longnose skate Raja rhina, Pacific hakes Merluccius productus, rex soles Glyptocephalus zachirus, bigfin eelpout Lycodes cortezianus, and sandpaper skate Bathyraja interrupta. Darkblotched rockfish Sebastes crameri, arrowtooth flounder Atheresthes stomias, and Pacific Ocean perch Sebastes alutus were identified as a shallow, northerly assemblage. The final group—sablefish Anoplopoma fimbria, brown cat sharks Apristurus brunneus, aurora rockfish Sebastes aurora, Dover soles Microstomus pacificus, and shortspine thornyheads Sebastolobus alascanus—occurred at different depths over a range of latitudes and might be best described as a shallow–middepth and midlatitude–southern grouping.

Shape, flapping and flexion: wing and fin design for forward flight.

Both kinematics and morphology are critical determinants of performance in flapping flight. However, the functional consequences of changes in these traits are not yet well understood. Traditional aerodynamic studies of planform wing shape have suggested that high-aspect-ratio wings generate more force per area and perform more efficiently than low-aspect-ratio wings, but these analyses may neglect critical components of flapping flight such as unsteady fluid dynamics and wing or fin flexion. In this paper, we use an unsteady potential flow analysis that incorporates wing flexion to test predictions of optimal wing shape under varying degrees of unsteady motion and wing flexion. We focus on forward flapping flight and examine the effects of wing/fin morphology and movements on thrust generation and efficiency. We test the model by comparing our predictions with kinematic data derived from the aquatic flight of the ratfish Hydrolagus colliei. Our analyses show that aspect ratio and the proportion of area in the outer one-fifth of the wing can characterize wing shape in terms of aero- or hydrodynamic performance. By comparing the performance of wings that vary in these two parameters, we find that traditional predictions of optimal wing shape are valid only under limited circumstances (when flapping frequency is low, wings are stiff or wings are tapered at the tips). This indicates a complex relationship between locomotor traits and performance and helps explain the diversity of wing kinematics and morphologies observed in nature.

Long‐term transportation of ratfish, Hydrolagus colliei, and tiger rockfish, Sebastes nigrocinctus

AbstractOn December 10, 2000, five tiger rockfish, Sebastes nigrocinctus, and 10 ratfish, Hydrolagus colliei, were transported from Vancouver, Canada, to Lisbon, Portugal, for 51 and 44 hours, respectively. The transport vessels consisted of large circular tanks (1.0‐m diameter × 0.6 m high) and filtration was added to the rockfish tank only. Filtration consisted of a combination of cartridge and activated carbon, powered by a 12‐V bilge pump placed on the middle of the transport vessel. Water quality parameters (ammonia, temperature, and oxygen saturation) were tested during the transport, and an ammonia detoxifier was added to some of the transport vessels when ammonia concentration reached 0.25 mg/L. Sodium bicarbonate was also added for pH buffering. All animals survived the trip and the subsequent 4 weeks. The water quality monitoring and treatment regimen therefore seemed appropriate for this type of long‐term transportation. Zoo Biol 20:435–441, 2001. © 2001 Wiley‐Liss, Inc.